Patran 2008 R1 Interface To Marc Preference Guide

Patran 2008 r1 Interface To Marc Preference Guide

Main Index

Corporate

Europe

Asia Pacific

MSC.Software Corporation 2 MacArthur Place Santa Ana, CA 92707 USA Telephone: (800) 345-2078 Fax: (714) 784-4056

MSC.Software GmbH Am Moosfeld 13 81829 Munich, Germany Telephone: (49) (89) 43 19 87 0 Fax: (49) (89) 43 61 71 6

MSC.Software Japan Ltd. Shinjuku First West 8F 23-7 Nishi Shinjuku 1-Chome, Shinjuku-Ku Tokyo 160-0023, JAPAN Telephone: (81) (3)-6911-1200 Fax: (81) (3)-6911-1201

Worldwide Web www.mscsoftware.com

Disclaimer This documentation, as well as the software described in it, is furnished under license and may be used only in accordance with the terms of such license. MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice. The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein. User Documentation: Copyright ©2008 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved. This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the prior written consent of MSC.Software Corporation is prohibited. The software described herein may contain certain third-party software that is protected by copyright and licensed from MSC.Software suppliers. Contains IBM XL Fortran for AIX V8.1, Runtime Modules, (c) Copyright IBM Corporation 1990-2002, All Rights Reserved. MSC, MSC/, MSC Nastran, MD Nastran, MSC Fatigue, Marc, Patran, Dytran, and Laminate Modeler are trademarks or registered trademarks of MSC.Software Corporation in the United States and/or other countries. NASTRAN is a registered trademark of NASA. PAM-CRASH is a trademark or registered trademark of ESI Group. SAMCEF is a trademark or registered trademark of Samtech SA. LS-DYNA is a trademark or registered trademark of Livermore Software Technology Corporation. ANSYS is a registered trademark of SAS IP, Inc., a wholly owned subsidiary of ANSYS Inc. ACIS is a registered trademark of Spatial Technology, Inc. ABAQUS, and CATIA are registered trademark of Dassault Systemes, SA. EUCLID is a registered trademark of Matra Datavision Corporation. FLEXlm is a registered trademark of Macrovision Corporation. HPGL is a trademark of Hewlett Packard. PostScript is a registered trademark of Adobe Systems, Inc. PTC, CADDS and Pro/ENGINEER are trademarks or registered trademarks of Parametric Technology Corporation or its subsidiaries in the United States and/or other countries. Unigraphics, Parasolid and I-DEAS are registered trademarks of UGS Corp. a Siemens Group Company. All other brand names, product names or trademarks belong to their respective owners.

P3*2008R1*Z*MA*Z* DC-USR

Main Index

Contents Marc Preferance Guide

1

Overview Purpose

2

Preference Components 3 Forward Translation and Analysis Execution Reverse Translation 5 Input File Import 6 File Descriptions 6 Template Databases 9 Analysis Submission Configuration 10

4

Getting Started 16 Building a Model 17 Analysis Processing 18 How this Manual is Organized

2

27

Building A Model Overview

30

Geometry - Coordinate Frames

31

Finite Elements - Multi-Point Constraints Nodes 32 Elements 33 Multi-Point Constraints 33 Loads and Boundary Conditions - Contact Static Load Case Input 46 Time Dependent Load Case Input 47 Object Tables 48 Material Library 74 Material Input Properties Constitutive Model Status Experimental Data Fitting

Main Index

79 110 111

32

44

iv Marc Preferance Guide

Element Properties 119 Element Input Properties 134 0D Elements 135 1D Elements 135 1D Shell/Membrane Elements 145 2D Elements 149 2D Solid Elements 150 3D Elements 153 Material Orientation 154 Elements in Coupled Analysis 155 Rebar Definition Tool 157 Load Cases

164

Fields - Tables 166 Fields Overview 167 Material Fields 169 Spatial Fields 178 Non-Spatial Fields 178

3

Running an Analysis Overview

182

Job Parameters 184 Loads on Geometry 187 Solvers / Options 190 Contact Parameters 192 Direct Text Input 200 Groups to Sets 202 Restart Parameters 204 Adaptive Meshing 206 User Subroutine File 220 Rebar Selection 226 Radiation Viewfactors 226 Cyclic Symmetry 229 Load Step Creation 232 Structural, Thermal, and Coupled Solution Types Solution Parameters 235 Common Solution Parameters 265 Select Load Case 313 Output Requests 314 Direct Text Input 331

Main Index

233

CONTENTS v

Load Step Selection Multiphysics Selection

333 334

Domain Decomposition DDM Interface 335 DDM Submittal 339 DDM Configuration 340

335

Resolving Convergence Problems

4

342

Read Results Read Results Form

348

Select Results File

349

Translation Parameters 350 Result Attachment Translation Parameters 350 Result Import Translation Parameters 351 Results Created in Patran Direct Results Access Rigid Body Animation

5

353

362 362

Exercises Overview

366

Exercise 1 - Build a Cantilever Beam Exercise 2 - A Simple Static Load

370 378

Exercise 3 - Buckling of a Fixed Pinned Beam Exercise 4 - Cumulative Loading

398

Exercise 5 - A Simple Contact Problem Exercise 6 - Nonlinear Material Plasticity Exercise 7 - Contact with Velocity Control Exercise 8 - Creep Analysis

411 420 430

436

Exercise 9 - Natural Frequency Analysis Exercise 10 - Transient Dynamic Analysis

Main Index

388

445 454

vi Marc Preferance Guide

Exercise 11 - Frequency Response Analysis Exercise 12 - Heat Transfer Analysis

481

Exercise 13 - Thermal-Mechanical Analysis

A

Supported Keywords Parameter Cards

500

Model Definition

502

History Definition

B

508

Transition Guide Overview 512 Capabilities and Features 512 Model Conversion 513 Defaults 514 Nomenclature 514 Material Properties 515 Element Properties 515 Load/Boundry Conditions (LBC's) 516 Reference Section 517 Frequently Asked Questions 519 520

Main Index

472

490

Chapter 1: Overview Marc Preference Guide

1

Main Index

Overview



Purpose



Preference Components



Getting Started



How this Manual is Organized

2 3

16 27

2 Marc Preference Guide Purpose

Purpose The Marc Preference provides a communication link between Patran and Marc. It customizes certain features of Patran by selecting Marc as the analysis code preference. Specifically these customized features are: multi-point constraints, materials, element properties, loads and boundary conditions (including contact), and analysis setup parameters. MSC.AFEA is a special product package consisting of Marc, Patran, and the Marc Preference offered by the MSC.Software Corporation at a reduced price relative to purchasing all the components separately. Marc is a general-purpose finite element computer program for engineering analyses specializing in product simulation and manufacturing processes. It is developed, supported, and maintained by the MSC.Software Corporation. See the Marc documentation for a description of specific capabilities. Patran is the name of a suite of products also written and maintained by the MSC.Software Corporation (MSC). The core of the system is Patran, a finite element analysis pre- and postprocessor. The Patran system also includes several optional products such as advanced postprocessing, other tightly coupled solvers, and interfaces to third party solvers. The difference between the product package, MSC.AFEA, and simply purchasing the individual components (Marc, Patran, and the Marc Preference) separately is the licensing scheme or mechanism. With MSC.AFEA licensing, Marc and Patran are interlocked. This means that an analysis can only be run on the machine from which it is submitted. It also means that only those features accessible through the graphical interface are supported. Purchasing the components separately gives you much more flexibility in that you can run the analysis on any machine and edit the input deck to access advanced analysis features that may not be available directly through Patran and the Marc Preference. However, MSC.AFEA provides a very cost effective solution. In either case, most access to Marc functionality is seamlessly integrated into Patran via the Marc Preference. The casual user will never need to be aware that separate programs are being used. However, for a full understanding of the mechanisms and processes there are a number of components to the Marc Preference explained in the next section, Preference Components.

Main Index

Chapter 1: Overview 3 Preference Components

Preference Components The Marc Preference includes all of the following items: 1. A PCL function contained in the p3patran.plb PCL library which will add Marc specific definitions to any Patran database (not already containing such definitions) at any time. 2. The PCL library called mscmarc.plb contained in the , also referred to as P3_HOME which can be set and referred to as an environment variable ($P3_HOME). This library is used by Patran to display analysis code specific job parameters, solution parameters, etc. It is automatically accessed when the Analysis Preference is set to Marc. 3. Three executable programs call marcp3, marpat3 and pat3mar contained in the $P3_HOME/bin/exe directory. These programs translate information from Marc files into Patran databases or translate information from Patran into Marc input files. These programs can be run independent of Patran but typically run transparently to the user. 4. Script files, executables and/or shared libraries contained in the $P3_HOME/bin/exe or $P3_HOME/lib directory. These control the execution of the executable programs mentioned above plus the submittal of Marc analyses. 5. This MSC.Marc Preference Guide. An online version is also provided to allow the direct access to this information from within Patran. The diagrams shown below indicate how the functions, scripts, programs, and files which constitute the Marc Preference affect the Patran environment. Site customization, in some cases, is indicated. MSC.AFEA also includes Marc and Patran in addition to the Marc Preference and its components as described above. An example of an for separately installed components of Patran and Marc might be: c:\msc\patran200x c:\msc\marc200x and example of an MSC.AFEA installation might be: c:\msc\afea\patran200x c:\msc\afea\marc200x The P3_HOME variable refers to the Patran portion of the installation, e.g., c:\msc\patran200x or c:\msc\afea\patran200x in the above examples.

Main Index

4 Marc Preference Guide Preference Components

Forward Translation and Analysis Execution Figure 1-1 shows the process of running an analysis. The mscmarc.plb library defines the necessary input required by the Analysis application in Patran. When a job is submitted for analysis, the forward translator, pat3mar, is invoked and Patran operation is suspended as data is read from the database and the Marc input file, named jobname.dat, is created. (A message file, named jobname.msg, is also created to record the translation messages, but these messages also appear in the Patran command window.) If pat3mar finishes successfully and the user has requested it, the shared library marcmonitor.dll prepares the job and starts the MarcSubmit program, which then controls the submittal of the analysis. Through MarcSubmit and the marcmonitor.dll shared library, the job can be monitored and controlled directly from the Marc Preference in Patran.

Figure 1-1 Note:

Main Index

Forward Translation and Analysis Execution

The MarcSubmit program is not used when the Patran Analysis Manager is used to submit and manage analysis jobs. The Patran Analysis Manager replaces the function of MarcSubmit and the marcmonitor.dll shared library. See the Patran Analysis Manager User’s Guide.

Chapter 1: Overview 5 Preference Components

Reverse Translation Figure 1-2 shows the process of accessing data from an Marc analysis results file back into Patran for postprocessing. When results are accessed, a job control file, named jobname.jbr, is created. The results are then either directly imported into the Patran database or attached, in which case they remain in the results (POST) file. Results are imported via the ResultsSubmit script and the marpat3 executable where Patran is suspended while this conversion occurs. However, results are attached via routines in the marcdra.dll dynamically linked library. This is called direct results access or DRA. While the POST file is attached, data is retrieved from it on an as-needed basis when postprocessing plots are made. If the POST file is deleted, detached, or renamed, the results will no longer be accessible in Patran. A message file is created to record the translation messages.

Figure 1-2

Main Index

Results Translation

6 Marc Preference Guide Preference Components

Input File Import Figure 1-3 shows the process of reading model data from an Marc input file. When the file is imported, Patran is suspended while this conversion occurs by running a program called marcp3. Two files are created to record the translation messages. marcp3 reads the data from the Marc input file and loads the Patran database directly. Any errors that occur are reported in the jobnmane.err file and any Marc keywords and data not recognized or supported are dumped to the reject file, jobname.rej. Information from the input file that ends up in the reject file can be included with a subsequent job setup via the Preference using the direct text input capability. This text will then be saved with the job directly in the Patran database. See Job Parameters for more detail on this feature.

Figure 1-3

Input File Translation

File Descriptions The table below lists all files either used or created by MSC.AFEA or the Marc Preference. The occurrence of name or jobname in the definition should be replaced with the database name or jobname respectively, assigned by the user.

Main Index

Chapter 1: Overview 7 Preference Components

File Name name.db

This is the Patran database from which the model data is read during translation, and into which model and/or results data is written during a read operation.

name.db.jou patran.ses.xx

A journal file records all commands issued in Patran (or MSC.AFEA) associated to a particular database. Also a separate session file, which gets versioned (.xx), is created each session. All commands during that session are recorded in this session file. The session files can be played back (File | Session | Play) or the journal file relayed to reproduce the model (File | Utilities | Rebuild).

jobname.jba

These are small control files used to pass certain information between Patran and the Marc Preference executables during translation. The user should never have a need to do anything with these files, except delete them as necessary.

jobname.jbr

Main Index

Description

jobname.dat #jobname.dat

This is the Marc input file created by MSC.AFEA or the Marc Preference for an analysis (or read to import model data). When domain decomposition is used, multiple files are produced where # is the domain number.

jobname.t16 #jobname.t16

This is the Marc binary results (POST) file created by an Marc analysis the contents of which can be imported or attached for postprocessing. When domain decomposition is used, multiple files are produced where # is the domain number.

jobname.t19 #jobname.t19

This is the Marc ASCII results (POST) file created by an Marc analysis the contents of which can be imported or attached for postprocessing. When domain decomposition is used, multiple files are produced where # is the domain number.

jobname.log #jobname.log

This is the log file from the Marc execution. Check it for any possible errors in the job. When domain decomposition is used, multiple files are produced where # is the domain number.

jobname.sts

This is the Marc status file which is a tabular listing of step, increment, and iteration information. Check it during an analysis to monitor progress or completion.

jobname.out #jobname.out

This is the Marc output file. Most errors are reported in this file if a job is unsuccessful. When domain decomposition is used, multiple files are produced where # is the domain number.

jobname.t08

This is a restart file produced by Marc when a restart job is requested. To restart from a previous job, you must reference this file.

marcp3*.msg

This file contains any error or informational messages from the may have occurred when importing data from an Marc input file (jobname.dat).

jobname.rej

This file contains any keywords and data not recognized when importing data from an Marc input file (jobname.dat).

8 Marc Preference Guide Preference Components

File Name

Main Index

Description

jobname.msg

This message file contains any diagnostic output from the translation, either forward (when submitting an Marc analysis) or reverse (when accessing results). This is an important file to check if analysis execution is not successful.

sgmps.log nurbtrans.log

Check the contents of these files, If errors occur on translation of rigid bodies to the Marc input deck.

metis*

These are various diagnostic files created when automatic domain decomposition is used (MARC_DEBUG environment variable set to YES).

Chapter 1: Overview 9 Preference Components

Template Databases When you create a new model (or database) in Patran or with MSC.AFEA, you open a template database stored in the installation directory (referred to as P3_HOME). Three versions of the template Patran database are delivered as standard. They are located in P3_HOME and are named base.db, mscmarc_template.db, and template.db. The former (base.db) is an Patran database into which no analysis code specific definitions, such as element types and material models, have been stored. The latter (template.db) is a version which contains many analysis code specific definitions already defined, which is the default used when creating a new database for Patran. Because definitions of other analysis codes are contained in this default template database, it is larger than needs to be if only Marc (or MSC.AFEA) is to be used. If you wish to use a database that contains only Marc specific analysis code definitions, use the mscmarc_template.db template delivered in P3_HOME when creating a new database (or rename it to template.db such that it becomes the default). Note:

Typical installations on Windows platforms of MSC.AFEA will only have Marc available as the analysis code in the default template database.

In order to create a template database which contains only Marc specific definitions, follow these steps: 1. Open a new database under File|New in Patran but specify base.db as the template. This is done in the file browser that appears. 2. Enter load_mscmarc() into the command line. This command adds the Marc specific definitions into the database for Marc versions K7, 2000, 2001, and 2003. 3. Save this database under a name like marc.db to be your new Marc only template database or call it template.db and replace the original in P3_HOME. 4. From then on, if you have not replaced template.db, choose marc.db as your template when creating a new database. For more details about adding analysis code specific definitions to a database and/or creating unique template databases, refer to Modifying the Database Using PCL (Ch. 1) in the PCL and Customization or to the Patran Installation and Operations Guide.

Main Index

10 Marc Preference Guide Preference Components

Analysis Submission Configuration The MarcSubmit executable controls the execution of the Marc analysis code. It is located in the UNIX directory called: $P3_HOME/bin/exe/MarcSubmit or on Windows: $P3_HOME\bin\MarcSubmit.exe where P3_HOME is the installation directory (and the $ indicates its use as a variable). The information that MarcSubmit uses to perform its operations can be categorized as either specific to the job or the site. The job specific information is automatically supplied by Patran (or MSC.AFEA) at run time. The site specific information is set at the time of installation and should not have to be set or reset unless the physical location of Marc (or MSC.AFEA), is changed or possibly if the different components are installed separately. Site specific information is set up specific to the platform type. In most cases you should never have to modify them. However, if a change occurs, you simply edit the UNIX site setup file: $P3_HOME/site_setup or the Windows site file: $P3_HOME\P3_TRANS.INI Note:

The explanations in this section do not apply if you are using the Patran Analysis Manager to submit and manage analysis jobs from Patran (or MSC.AFEA). The Patran Analysis Manager must be separately configured and will override any settings here. If you have the Patran Analysis Manager installed but wish to use this method of submittal you can type analysis.manager.disable() in the Patran command line or include it in startup session file script. To re-enable Patran Analysis Manager, use analysis.manager.enable(). See the Patran Analysis Manager User’s Guide.

UNIX Site Setup The site_setup file contains the following environment variables corresponding to the parameters in the MarcSubmit program: setEnv setEnv setEnv setEnv setEnv setEnv setEnv setEnv setEnv

MSCP_MARC_HOST7 <machine name where MARC K7 resides> MSCP_MARC_HOST2000 <machine name where MSC.Marc 2000 resides> MSCP_MARC_HOST2001 <machine name where MSC.Marc 2001 resides> MSCP_MARC_HOST2003 <machine name where MSC.Marc 2003 resides> MSCP_MARC_SCRATCHDIR <path of scratch directory> MSCP_MARC_CMD7 MSCP_MARC_CMD2000 MSCP_MARC_CMD2001 MSCP_MARC_CMD2003

The MSCP_MARC_HOST# parameter defines the machine that is used to perform the Marc analysis. When this parameter is set to LOCAL, the analysis is performed on the same machine as the Patran (or MSC.AFEA) session. (pat3mar translations are always performed on the same machine as the session. This only affects where Marc is run.)

Main Index

Chapter 1: Overview 11 Preference Components

The SCRATCHDIR parameter defines the directory on the host machine that temporarily holds the analysis files as they are created. The advantage of having a scratch directory is that the contents of the analysis scratch files are never transferred across the network. This benefit is not achieved when the HOST parameter is set to LOCAL, so the SCRATCHDIR parameter is ignored for this condition. The MSCP_MARC_CMD#, parameter defines the path and file name of the scripts that run the K7, 2000, 2001, or 2003 versions of the Marc analysis code. MarcSubmit uses this parameter to point to MARC K7, Marc 2000, Marc 2001, or Marc 2003 installations, respectively. As an example, for a local installation of Marc 2001, you would need at a minimum, the following: setEnv MSCP_MARC_HOST2001 LOCAL setEnv MSCP_MARC_CMD2001 /msc/marc2001/tools/run_marc For a remote host you would need the following as an example: setEnv MSCP_MARC_HOST2001 baytown setEnv MSCP_MARC_SCRATCHDIR /tmp setEnv MSCP_MARC_CMD2001 /msc/marc2001/tools/run_marc Note:

All of the above parameters can also be set as environment variables. If the system detects that one of more of these environment variables has been set, they override the settings in site_setup. This way you can temporarily change settings without editing the site_setup file.

Windows The same information is needed on the Windows platform as for UNIX as described above. However, on the Windows platform, the site specific parameters are found in the $P3_HOME\P3_TRANS.INI file. The run_marc command on Windows must be specified by its full file name which is run_marc.bat. As an example, for a local installation of Marc 2001, you would need at a minimum, the following under the [MscMarc] section of the P3_TRANS.INI file: [MscMarc] Host=LOCAL Hosttype=Windows Acommand2001=c:\msc\marc2001\tools\run_marc.bat For a remote host (UNIX) submittal you would need the following as an example: [MscMarc] Host2001=dallas Hosttype=UNIX Scratchdir=/tmp/marctmp Acommand2001=/msc/marc2001/tools/run_marc Outputfiles=out,log,t16,t19,* OutputTypes= a, a, b, a,b The last two entries, determine which output files, by their suffix names, will be transferred back to the submitting host when the job is completed and the type of file it is (ASCII=a or binary=b). A wild card (*) can be used to specify all output files.

Main Index

12 Marc Preference Guide Preference Components

Note:

Patran versions prior to 2003 used a script or executable (on Windows) called MarcExecute(.exe). This has been obsoleted in this version, however, if you wish to continue to use it, set the environment variable MARCEXECUTE to YES. With this method of remote submittal from a Windows machine to any other machine requires a remote shell service running on your Windows machine(s). For more information on this see Module and Preference Setup (p. 14) in the Patran Installation and Operations Guide

Remote Submittal Program Remote submittal (not via the Patran Analysis Manager) is accomplished using a separately spawned program called MarcSubmit and can be executed independently of Patran, however this should never be necessary. This section is included for completeness. Only UNIX to UNIX or Windows to UNIX remote submittal is supported. (For more complex remote submittals use the Patran Analysis Manager.) Simply typing the name of the program at the command prompt will list all the necessary or acceptable input arguments. For example: $P3_HOME/bin/MarcSubmit will result in: MarcSubmit -j jobname -m marcversion [-h host] [-s scratchdir] [-v] [-l logfile] -c command_file Arguments: -j -job Required - job name -m -marcversion Required - Marc Version -v -verbose Have the program print out every command executed and its status at completion. -l logfile

Logfile to output results of commands to.

-c command_file File which contains the list of input files, the command to be issued, and the list of expected output files. This is an xml-like file of the form (in any order): input file names command output file names host computer host type - UNIX or windows <scratchdir>scratch directory.

Arguments with brackets around them are optional. An example might be: $P3_HOME/bin/MarcSubmit -j s4 -m 2001 -c s4.cmd At a minimum, the jobname, marcversion and command_file need to be supplied. The other arguments are optional and obtained from different sources such as UNIX environment variables or through the site_setup or P3_TRANS.IN files. If provided as command arguments, they take precedent over any other settings. The command_file is created by the marcsubmit.dll when the job is submitted and deleted at job completion. An example is shown here: /solvers/marc2001/tools/run_marc -j s4 -b yes -v no tavarua UNIX <scratchdir>/tmp/marctmp

Main Index

Chapter 1: Overview 13 Preference Components

s4.dat; s4.dat;s4.log;s4.sts;s4.out;s4.t16; 300

is the actual submittal command to execute on the remote called tavarua which of UNIX and should execute in <scratchdir> /tmp/marctmp. The input files to copy to the remote host and output file to copy back are listed, separated by semicolons. If a user subroutine is used, sets the compile and link time before checking for a time out. If the time is not sufficient, then the monitoring of the job (which is run by the MarcSubmit executable) starts looking for files and progress in the run. If it does not get any in 5 minutes, then it assumes that something is wrong and brings all the files back which essentially kills the job. So by default, the process allows for about 10 minutes to compile and run to the first job iteration (zeroth increment). If this is not sufficient there is a PCL command that can be issued at the command prompt or included in a startup file such as p3epilog.pcl or init.pcl, that will extend this: marc_set_compile_time( minutes ) Th e allowable ran ge is an in teger between 1 and 60 minutes.

Note:

MSC.AFEA only supports local submittals. The above documented command_file is only used for remote submittals. To manually submit an Marc job locally, just use the run_marc script directly as explained in the Marc documentation.

Submittal to LSF Queues There is some basic support for submittals of Marc to LSF queues. LSF (Load Sharing Facility) is a widely used, load management software utility available from Platform Computing, headquartered in Ontario, Canada. LSF is particularly useful in a network of computers for determining least loaded CPUs. From this information, domain decomposition (parallel) jobs can be run most efficiently since LSF automatically chooses the least loaded hosts. This also eliminates the need for the user to prepare and decide (ahead of time) which machines to submit to. In order to submit Marc jobs to an LSF queue via Patran, the following limitations and requirements exist: 1. Only submission to a cluster of UNIX machines is supported. The submittal machine must also be a UNIX machine. Windows is not supported at this time. 2. Both local and remote submittals are supported. That is, you may submit a job from a machine that is not configured with LSF to a machine that is configured with LSF. This is considered a remote submittal. A job submitted locally with LSF configured on the local machine is considered a local submittal. 3. The job must be submitted from a shared directory. In other words, all machines that will or could potentially run Marc parallel jobs, must be able to see the directory from which the job is submitted. (Files are not copied to local directories and then back to the submittal directory.)

Main Index

14 Marc Preference Guide Preference Components

4. Marc must be seen from all machines that potentially will run in parallel mode in exactly the same way. For example, if on machine A, the run_marc command is in /msc/marc2001/tools/run_marc, then it must be also on machine B. If this is not the case, then you must set up symbolic links to make it so. This could be done by putting symbolic links on all machines in the LSF network such that a link /usr/bin/run_marc points to whereever run_marc is located on each machine. You will need root access to do this. 5. The LSF command bsub is used to submit a job. It must be seen in the user’s path. The LSF environment is setup by sourcing the LSF C-shell script cshrc.lsf. See the LSF documentation for more details on the LSF operating environment. You may also create a symbolic link in /usr/bin to point to whereever the LSF bsub command is located since this is usually in the user’s path. You’ll need root access to do this. 6. Only homogeneous machines are supported. Example: if you submit to an HP machine, then only HP machines will be chosen as valid machines to run the parallel job. In the site_setup file (see UNIX Site Setup), you will need to define one additional variable. This can be done in the site_setup file and can also be done by defining the environment variable manually or via a startup script or other mechanism. The variables necessary in the site_setup file for LSF submittal are at a minimum one of: setEnv MSCP_MARC_HOST2001 LOCAL setEnv MSCP_MARC_HOST2003 LOCAL or for remote submittal: setEnv MSCP_MARC_HOST2001 <machine with LSF for 2001 submittals> setEnv MSCP_MARC_HOST2003 <machine with LSF for 2003 submittals> This variable should NOT be set as the shared directory must be used. Make sure you have enough disk space in the shared directory. setEnv MSCP_MARC_SCRATCHDIR <path of scratch directory> To enable the LSF submittal, this variable must be set to yes: setEnv MSCP_MARC_USE_LSF yes If you wish to change the queue name to which a job is submitted, you must define this variable, otherwise all jobs are submitted to the default queue, which is generally called normal. setEnv MSCP_MARC_LSF_QUEUE normal If you require additional or more advanced submittal access and you are proficient with LSF, you may include additional items onto the submittal line by defining them in this variable, which is used to build up the LSF resource string: setEnv MSCP_MARC_LSF_RESSTR For example if you wanted to only submit to machines with a certain amount of memory and swap available, you would define, say: setEnv MSCP_MARC_LSF_RESSTR (mem>15)&&(swp>50)

Main Index

Chapter 1: Overview 15 Preference Components

Any string that can legally be placed in the LSF resource string can be defined by this variable. The above would submit a local job with bsub -q normal -R "select[(mem>15)&&(swp>50)]" where is the run_marc command plus all of its necessary arguments.

Main Index

16 Marc Preference Guide Getting Started

Getting Started

Everything begins in Patran (or MSC.AFEA) by opening a new database from File | New. When a new database is opened, a form initially appears also, allowing you to set the analysis preference. In order to submit a model for analysis using Marc, the analysis preference must be set to Marc. The analysis preference may be changed from the Preferences | Analysis menu also. The analysis code may be changed at any time during the model creation. This is especially useful if the model is to be used for different analyses, in different analysis codes. As much data as possible will be converted if the analysis code is changed after the modeling process has begun. The analysis option defines what will be presented in several areas during the subsequent modeling steps. These areas include the material and element libraries, plus multi-point constraints, loads, boundary conditions, contact definitions, and the analysis setup forms. The selected analysis code may also affect the selections in these same areas. For more details, see Analysis Codes (p. 426) in the Patran Reference Manual.

Main Index

Chapter 1: Overview 17 Getting Started

Building a Model Patran (or MSC.AFEA) is a general purpose finite element pre- and postprocessor. Finite element models can be built for multiple purposes. It is not the intention of this manual to teach the finer points of model building, but rather, to document specifics about preparing a model for analysis using Marc. You are referred to the general Patran User’s Guide for specifics on geometry import and creation and finite element meshing.

In general however, you start by importing or creating geometry using the File | Import or the Geometry application. The geometry is then meshed using the FEM application. Or an existing mesh can be imported. The process of building and preparing a model for Marc analysis generally follows a left to right operation across the Patran application menu bar: Geometry, FEM, LBCs, Materials, Properties, Load Cases, etc. Building A Model and the table below outline the operations of each application involved in model building and analysis preparation: Application

Main Index

Description

Geometry

Creates the geometric representation of your model. You can also import geometry from CAD under the File | Import menu. CAD geometry can then be manipulated, repaired, or modified in the Geometry application. This is a generic operation independent of any Marc analysis. Coordinate frames are also created under this application. See Geometry - Coordinate Frames for supported coordinate definition keywords.

Finite Elements (FEM)

Allows you to create a finite element mesh of your geometric model. Or the mesh can be imported independent of any geometry under the File | Import menu or the Analysis application. This is a generic operation independent of any Marc analysis.(However you must be aware of the proper element topologies valid for a valid Marc analysis.) The exception to this are MPCs and rigid type elements which are specific to Marc. These are also defined in the FEM application. See Multi-Point Constraints for list of supported MPC and rigid elements.

18 Marc Preference Guide Getting Started

Application

Description

Loads and Boundary Conditions (LBCs) (Contact)

Allows you to apply boundary conditions (constraints) and loads to your model on either the geometry or the actual finite element mesh. Contact definitions are considered a type of boundary condition and are specified here. Only LBCs allowed in Marc are available in this application when Marc is the analysis preference. See Loads and Boundary Conditions - Contact for supported loads and boundary conditions.

Materials

Material properties are defined from the Marc material library in this application. See Material Library for the complete material library.

Properties

Element properties are defined in this application. The properties associated to a group of elements or mesh are specified including a reference to the appropriate material(s). This application defines which Marc element types will actually be used in an analysis. See Element Properties for supported element types and their corresponding properties.

Load Cases

Loads and boundary conditions can be grouped together into various load cases. Multiple load cases can be created with any combination of grouped LBCs. Contact tables are not part of these load cases, but are defined in the Analysis application. Static versus transient loading is defined in this application. Although the transient definition of a particular load is defined in the Fields application and associated to the load in the LBCs application. The LBCs with transient definitions must be associated to a transient load case or they will not be treated as transient. See Load Cases

Fields

Time and frequency dependent as well as spatial fields (tables) can be created in this application. Properties that vary spatially and/or loads that vary with time or frequency must reference a table definition created in the Fields application. See Fields - Tables

Building A Model explains, in detail, the process of building a model.

Analysis Processing After the model is created with all its appropriate materials, properties, loads, boundary conditions, etc., it is ready for submission to Marc for analysis. A job is then created in the Analysis application with all the pertinent parameters specified. The job is submitted and the results are read back into Patran for postprocessing in the Results, or XY Plot applications.

Main Index

Chapter 1: Overview 19 Getting Started

Application

Description

Analysis

The Analysis application is the culmination of the model building and preparation activity where an actual analysis job is set up and submitted. Various analysis specific (as opposed to model specific) parameters are set up including translation parameters, output requests, contact tables, solution types, etc. When the analysis is complete, the results are read back in with this application also. Result postprocessing is then performed in the Result application. See Running an Analysis for an explanation of all supported analysis options and parameters.

Results

These are result postprocessing applications. Fringe plots of various requested output quantities can be visually displayed. XY plots created under the Results application can be manipulated and modified in the XY Plot application. See Results Created in Patran for a list of supported results entities.

XY Plot

Running an Analysis explains, in detail, the process of setting up an analysis for submission while Read Results explains how to read results back into Patran for postprocessing.

There are seven (7) possible Actions in the Analysis application. These are Analyze, Read Results, Read Input File, Delete, Monitor, Abort, and Run Demo. Each of these is briefly explained below. Analysis Submission (Action: Analyze) When a job is ready for analysis, the Action is set to Analyze. A jobname is given (and description if desired) and the Apply button is pressed. See Running an Analysis.

Main Index

20 Marc Preference Guide Getting Started

Results Access (Action: Read Results) When a job is completed, the Action is set to Read Results to read the results (POST) file in and postprocess. See Read Results.

Data Import (Action: Read Input File) An existing Marc input file can be read into Patran. Set the Action to Read Input File, select the input file, and press the Apply button. A list of supported Marc keywords can be found in Supported Keywords.

Main Index

Chapter 1: Overview 21 Getting Started

Job or Result Deletion (Action: Delete) The Delete option under Action allows the user to delete jobs or results POST file attachments.

Main Index

22 Marc Preference Guide Getting Started

Monitor a Job (Action: Monitor) The Monitor option under Action allows the user to view various files created by the analysis, do keyword searches of the jobname.out file which contains analysis results, and view the progress of a currently running job.

Main Index

Chapter 1: Overview 23 Getting Started

Note:

Main Index

The editor of choice must be in the user’s search path. If the operation appears not to work, check that the editor can be accessed from a command prompt by simply typing the name with no path. The default editor is xterm -exec vi on UNIX and notepad on Windows.

24 Marc Preference Guide Getting Started

This form appears after pressing the Apply button when monitoring a job (if no Patran Analysis Manager installed):

Note:

Main Index

You can disable/enable the Analysis Manager with these command: analysis_manager.disable(), analysis_manager.enable().

Chapter 1: Overview 25 Getting Started

Aborting a Job (Action: Abort) The Abort option under Action allows the user kill an Marc analysis.

Example Problems (Action: Run Demo) The Run Demo option under Action allows the user to run an example problem.

Main Index

26 Marc Preference Guide Getting Started

Note:

Main Index

If this menu item does not appear it is because the $P3_HOME/md_demos directory does not exist. This is fully customizable. See the Readme file in the same directory for more details.

Chapter 1: Overview 27 How this Manual is Organized

How this Manual is Organized This guide is organized in such a fashion that it can be used both as a reference and as a tutorial. • Overview is a brief overview of MSC.AFEA and the Marc Preference and explains its operation

and some customization capabilities. It also gives a general view of the capabilities and where to locate some of the standard functionality. • Building A Model is meant to be mostly a model building reference containing explanations of

how to create meshes, coordinates, materials, element properties, loads, boundary conditions including contact bodies, table or field data, load cases and multi-point constrains as they pertain to creating a valid Marc input file. • Running an Analysis is also mostly a reference chapter but for analysis specific setup parameters.

The details of specifying analysis solutions, solution parameters, contact control, contact tables, output requests, translation parameters, etc., are given in this Chapter. • Read Results explains how to read results back into the Patran database (or to attach to a results

file) and what actual Marc results file POST codes (result types) are supported for postprocessing. • Exercises is a tutorial which covers many aspects of proper usage of the Preference. This is

where most new user’s to MSC.AFEA and the Marc Preference should start. • Supported Keywords is a reference that lists all the supported Marc input file keywords and

indicates the location in this guide for explanation on how to set up the input in the Preference to obtain these keywords in your input file. • Transition Guide is a reference helps users transition to the Marc Preference from other

analysis codes. Note:

Main Index

The best way to learn MSC.AFEA or the Marc Preference and become proficient right away, is to work through the example problems in Exercises.

28 Marc Preference Guide How this Manual is Organized

Main Index

Chapter 2: Building A Model Marc Preference Guide

2

Main Index

Building A Model



Overview



Geometry - Coordinate Frames



Finite Elements - Multi-Point Constraints



Loads and Boundary Conditions - Contact



Material Library



Element Properties



Load Cases



Fields - Tables

30

74

165 167

120

31 32 44

30 Marc Preference Guide Overview

Overview

This Chapter concerns itself with creating a model in Patran (or MSC.AFEA) for submission to an Marc analysis. It is meant to be used more as a reference than anything else. In general the operation of creating a model follows a left to right access of the main Patran applications as shown above: Geometry, Finite Elements, Loads and Boundary Conditions, Materials, Properties, Load Cases, Fields. Each application allows you to define certain aspects of your model starting with the geometric definition including coordinate frames. The geometry is then meshed including the definition of rigid (MPC) elements and other 0D/1D elements such as springs, dampers, and gaps. Loads and boundary conditions are applied and contact bodies defined if required. Materials and properties are then assigned, which define the types of elements to be used by Marc. If more than one load case is required, they can be defined in the Load Cases application. And if any input requires tabular data to define time, temperature, or other spatially or otherwise varying properties, this is done under the Fields application. Once the model is created, the analysis may be set up and submitted. This is the subject of Running an Analysis. This Chapter details which Marc keywords are written to the Marc input file as defined in each Patran application. A list of all Marc supported keywords are listed in Supported Keywords. Only aspects relating to the creation of these keyword via Patran’s graphical user interface are explained in this chapter. The user is referred to the Patran User’s Guides for general pre-processing details on model creation.

Main Index

Chapter 2: Building A Model 31 Geometry - Coordinate Frames

Geometry - Coordinate Frames Coordinate frames created in Patran/MSC.AFEA will place the Marc TRANSFORMATION and CYLINDRICAL keywords for nodes that are assigned analysis coordinate frames into the Marc input file. Analysis coordinate frames are specified when nodes or meshes are created or modified, and when assigning a displacement boundary condition with an analysis coordinate frame. All Marc nodes will be defined in the global analysis coordinate frame unless the analysis coordinate frame references a cylindrical system in which case all nodal input and output will be relative to the specified cylindrical system. Rectangular coordinate frames are used to create the TRANSFORMATION keyword and cylindrical coordinate frames are used to create the CYLINDRICAL keyword. Local rectangular coordinate frames are created by first calculating the nodes distance from the global coordinate frame. Then, the distance is used to locate points one and two along the axes of the node’s local coordinate frame.

Main Index

32 Marc Preference Guide Finite Elements - Multi-Point Constraints

Finite Elements - Multi-Point Constraints The Finite Elements application in Patran (or MSC.AFEA) is used to define the basic finite element mesh. Use this application to create Marc nodes, elements, and multi-point constraints.

Nodes Nodes in Patran (or MSC.AFEA) will generate the Marc COORDINATES keyword in the input file. Create nodes either directly by using the Node object, or indirectly by using the Mesh object. An Marc TRANSFORMATION or CYLINDRICAL keyword and set is generated for each node associated to a local (non-global) analysis coordinate frame.

Main Index

Chapter 2: Building A Model 33 Finite Elements - Multi-Point Constraints

To modify the analysis coordinate frame of an existing mesh, use the Create|Node|Edit options in this application. When creating a mesh, use the Node Coordinate Frames button when the options are set to Create|Mesh.

Elements The Finite Elements application in Patran (or MSC.AFEA) assigns element topology, such as Quad4, Hex8, Tri6, etc. The type of Marc elements created however, are not determined until the element properties are assigned. See Element Properties for more information on Marc element types. Either create elements directly, by using the Element object, or indirectly by using the Mesh object. Both elements and nodes can be created simultaneously using the Create|Mesh options in this application or individual elements can be created using the Create|Element options. The Marc element type or number is entered in the first field of the third card of the CONNECTIVITY option in the Marc input file.

Note:

Actual Marc element types are not assigned until element properties are associated with the elements of the mesh. Care should be taken to make sure the proper element topology is used before assigning properties. For grounded springs/dampers, create point elements.

Multi-Point Constraints Multi-point constraints (MPCs) are created in the Finite Elements application by setting the Object to MPC. MPCs are special element types which define a rigorous behavior between several specified nodes.

Main Index

34 Marc Preference Guide Finite Elements - Multi-Point Constraints

The full functionality is described in Create MPC Sliding Surface Form (p. 127) in the Reference Manual - Part III.

Main Index

Chapter 2: Building A Model 35 Finite Elements - Multi-Point Constraints

Define Terms In general, for all MPC types except Cyclic Symmetry and Sliding Surface, dependent and independent terms must be specified including any degrees-of-freedom and/or coefficients associated with those terms on the form shown below. The operation is as explained:

A list of MPC types and their expected dependent and independent term information is given in MPC Types below.

Main Index

36 Marc Preference Guide Finite Elements - Multi-Point Constraints

Degrees-of-Freedom When a list of degrees-of-freedom are expected for an MPC term, a listbox containing the valid degreesof-freedom is displayed on the form. A degree-of-freedom is valid if: 1. It is valid for the current Analysis Code Preference. 2. It is valid for the current Analysis Type (structural/thermal). 3. It is valid for the selected MPC type. In most cases, all degrees-of-freedom which are valid for the current Analysis Code and Analysis Type are valid for the MPC type. The following degrees-of-freedom are supported by Marc MPCs for the various analysis types: Degree-of-freedom

Note:

Analysis Type

UX

Structural

UY

Structural

UZ

Structural

RX

Structural

RY

Structural

RZ

Structural

Temperature

Thermal

Top Temperature

Thermal

Middle Temperature

Thermal

Bottom Temperature

Thermal

No MPC types are defined for Coupled analysis. To use MPCs is a Coupled analysis, set the Analysis Preference to Structural or Thermal to define the MPCs you want, then set the Analysis Preference back to Coupled. Make sure that the degree-of-freedom selected for an MPC actually exists at the nodes. For example, a node that is attached only to solid structural elements will not have any rotational degrees-of-freedom. However, Patran will allow you to select rotational degrees-offreedom at this node when defining an MPC. This may not be allowed by Marc. Marc axisymmetric have three DOFs, namely Z, R, and Theta which correspond to the X, Y, and RX DOF in the global Patran system (DOFs 1,2 and 4 respectively).

MPC Types The following table describes the MPC types which are supported for Marc. Either SERVO LINK or TYING keyword options are created in the Marc input file. For TYING keyword options, the dependent

Main Index

Chapter 2: Building A Model 37 Finite Elements - Multi-Point Constraints

node ID is entered in the 2nd field of the 3rd data block, referred to as the tied node. The independent node IDs are entered on the 3a data block, referred to as the retained nodes. MPC Type • Explicit

Analysis Type Structural Thermal Coupled

Creates a SERVO LINK explicit MPC between a dependent degree-of-freedom and one or more independent degrees-of-freedom. The dependent term consists of a node ID and a degree-of-freedom, while an independent term consists of a coefficient, a node ID, and a degree-of-freedom. An unlimited number of independent terms can be specified, while only one dependent term can be specified.

• Rigid (Fixed)

Structural Coupled

Creates TYING Type 100 MPCs which constrains all degrees-of-freedom at one or more dependent nodes to the corresponding degrees-of-freedom at one independent node. An unlimited number of dependent terms can be specified, while only one independent term can be specified. Each term consists of a single node.

• Linear Surf-Surf

Structural Coupled

Creates a TYING Type 31 MPC which constrains a dependent node on one linear 2D element to two independent nodes on another linear 2D element to model a continuum. One dependent term is specified, while two independent terms are specified. Each term consists of a single node.

• Linear Surf-Surf

Thermal

Creates a TYING Type 87 MPC which constrains one dependent node to one independent node, which ties temperatures between shell elements. One dependent and one independent term are specified. A second independent term must be supplied but is ignored (it can be the same node). Each term consists of a single node.

• Linear Surf-Vol

Thermal

Creates a TYING Type 85 MPC which constrains a dependent node on one linear 2D element to two independent nodes on another linear 2D element to tie temperatures. One dependent term is specified, while two independent terms are specified. Each term consists of a single node.

• Linear Vol-Vol

Structural

Creates a TYING Type 33 MPC which constrains a dependent node on one linear 3D solid element to four independent nodes on another linear 3D solid element to model a continuum. One dependent term is specified, while four (three for degenerate face) independent terms must be specified. Each term consists of a single node.

Thermal Coupled

Main Index

Description

38 Marc Preference Guide Finite Elements - Multi-Point Constraints

MPC Type • Quad Surf-Surf

Analysis Type Structural Coupled

Creates a TYING Type 32 MPC which constrains a dependent node on one quadratic 2D element to three independent nodes on another quadratic 2D element to model a continuum. One dependent term is specified, while three independent terms are specified. Each term consists of a single node.

• Quad Surf-Surf

Thermal

Identical to Linear Surf-Surf for Thermal analysis except a third independent term must be supplied but is also ignored.

• Quad. Surf-Vol

Thermal

Creates a TYING Type 86 MPC which constrains a dependent node on one quadratic 2D element to three independent nodes on another quadratic 2D element to tie temperatures. One dependent term is specified, while three independent terms are specified. Each term consists of a single node.

• Quad Vol-Vol

Structural

Creates a TYING Type 34 MPC which constrains a dependent node on one quadratic 3D solid to eight independent nodes on another quadratic 3D solid element to model a continuum. One dependent term is specified, while eight (six for degenerate face) independent terms are specified. Each term consists of a single node.

(quadratic)

Thermal Coupled

• Tie DOFs

Structural Thermal Coupled

Main Index

Description

Creates a TYING Types 1-6 or 102-506 MPC which constrains two nodes at a selected degree-of-freedom or at a range of degrees-of-freedom. One dependent term is specified which consists of a single node. One independent term is specified which consists of a single node and either one or two selected degrees-of-freedom. The Marc type number will be determined by the selected degrees-of-freedom. If one degree-of-freedom is specified, a Type 1-6 MPC is created. If two degrees-offreedom are selected, a Type 102-506 MPC is created.

• Axi Shell-Solid

Structural Coupled

Creates a TYING Type 26 MPC which connects an axisymmetric shell element to a solid element. One dependent term is specified which consists of a single node. One independent term is specified which also consists of a single node.

• Tri Plate-Plate

Structural Coupled

Creates a TYING Type 49 MPC which connects triangular flat plate elements. One dependent term is specified which consists of a single node. One independent term is specified which also consists of a single node.

Chapter 2: Building A Model 39 Finite Elements - Multi-Point Constraints

MPC Type

Main Index

Analysis Type

Description

• Quad Plate-Plate

Structural Coupled

Creates a TYING Type 50 MPC which connects rectangular flat plate elements. One dependent term is specified which consists of a single node. One independent term is specified which also consists of a single node.

• Pinned Joint

Structural Coupled

Creates a TYING Type 52 MPC which creates a pinned joint between beam elements. One dependent term is specified which consists of a single node. One independent term is specified which also consists of a single node.

• Full Moment Joint

Structural Coupled

Creates a TYING Type 53 MPC which is a full moment joint between beam elements. One dependent term is specified which consists of a single node. One independent term is specified which also consists of a single node.

• Rigid Link

Structural Coupled

Creates a TYING Type 80 MPC which creates a pinned rigid link between two nodes. One dependent term is specified, while two independent terms are specified. The dependent term and the first independent term are the nodes at the ends of the link, while the second independent term is an unattached node that provides the rotational information about the link.

• Cyclic Symmetry

Structural Coupled

Creates a TYING Type 100 MPC which ties all degreesof-freedom between matched nodes on opposite sides of the cyclic sector. Unlimited nodes may be entered in the dependent and independent regions; however, the same number of unique nodes must be specified in both regions.

• Sliding Surface

Structural Coupled

Creates a SERVO LINK explicit MPC which ties the normal to the surface degrees-of-freedom between matched nodes on opposite sides of the interface. Unlimited nodes may be entered in the dependent and independent regions; however, the same number of unique nodes must be specified in both regions.

40 Marc Preference Guide Finite Elements - Multi-Point Constraints

MPC Type • RBE2

Analysis Type Structural

Description Creates an MD Nastran style RBE2 element, which defines a rigid body between an arbitrary number of nodes. Although the user can only specify one dependent term, an arbitrary number of nodes can be associated to this term. The user is also prompted to associate a list of degrees of freedom to this term. A single independent term can be specified, which consists of a single node. There is no constant term for this MPC type. The RBE parameter is also written.

Main Index

Chapter 2: Building A Model 41 Finite Elements - Multi-Point Constraints

MPC Type • RBE3

Analysis Type Structural

Description Creates an MD Nastran style RBE3 element, which defines the motion of a reference node as the weighted average of the motions of a set of nodes. A finite number of dependent terms can be specified, each term consisting of a single node and a list of degrees of freedom. The first dependent (tied) term is used to define the reference node. Any (optional) dependent terms define additional nodes/degrees of freedom (dofs) that are added to the m-set. These additional dependent (tied) nodes/dofs MUST be a subset of the independent (retained) nodes/dofs as defined next. An arbitrary number of independent (retained) terms must also be specified. Each independent term consists of a constant coefficient (weighting factor), a node, and a list of degrees of freedom. All nodes with the same weighting factor and dof list should be grouped together. There is no constant term for this MPC type and at the present time, the Thermal Expansion coefficient is ignored. The RBE parameter is also written.

• Overclosure

Main Index

Structural Thermal Coupled

Creates a TYING Type 69 MPC which is used for creating gaps or overlaps between two parts of a model either by prescribing the total force on the nodes on either side of the gap/overlap or by prescribing the size of the gap/overlap. This is typically used for pretensioning of bolts or rivets. Dependent terms contain one node each and independent terms contain two nodes each. Each dependent (tied) term consists of a node on one side of the gap/overlap. The first node of the independent (retained) term consist of the corresponding node on the other side of the gap/overlap. The second node of the independent term is a control node to which LBCs may be applied. Each independent term must have the same control node otherwise an error is issued. There must be the same number of independent vs dependent terms also, otherwise an error is issued. The control node should not be associated to any elements. In non-mechanical passes, this MPC reduces to a Type 100 between the dependent and first independent term internally to MSC.Marc.

42 Marc Preference Guide Finite Elements - Multi-Point Constraints

Cyclic Symmetry

This form appears when Cyclic Symmetry is the selected Type. Use this form to create the TYING Type 100 keyword option. The dependent (or tied) node IDs are entered in the 2nd field of the 3rd data block, and the independent (or retained) node IDs are placed on the 3a datablock.

Main Index

Chapter 2: Building A Model 43 Finite Elements - Multi-Point Constraints

Cyclic symmetry in Marc is generally performed with the CYCLIC SYMMETRY option rather than through MPC definitions. See Cyclic Symmetry. Sliding Surface

This form appears when Sliding Surface is the selected Type. Use this form to create the SERVO LINK keyword option. This MPC ties the normal to the surface degrees-of-freedom between matched nodes on opposite sides of the interface. The dependent and independent node IDs are entered on the second card of the SERVO LINK option.

Main Index

44 Marc Preference Guide Loads and Boundary Conditions - Contact

Loads and Boundary Conditions - Contact The Loads and Boundary Conditions application controls which loads and boundaries and contact information will be created in the Marc input file. For more information, see Loads and Boundary Conditions Form (p. 27) in the Patran Reference Manual.

Main Index

Chapter 2: Building A Model 45 Loads and Boundary Conditions - Contact

The following table lists the supported loads and boundary condition types:

Object

Analysis Type

Type

• Acceleration

• Structural, Coupled

Nodal

• Displacement

• Structural, Coupled

Nodal

• Release

• Structural, Coupled

Nodal

• Force

• Structural, Coupled

Nodal

• Pressure

• Structural, Coupled

• 1D Pressure

• Structural, Coupled

• Temperature

• Structural, Thermal,

Coupled

• Element Uniform

• 2D 3D

• Element Variable

• 2D 3D

Element Uniform

• 1D

• Nodal • Element Uniform

• 1D 2D 3D

• Element Variable

• 2D

• Inertial Load

• Structural, Coupled

Element Uniform

• Initial Displacement

• Structural, Coupled

Nodal

• Initial Velocity

• Structural, Coupled

Nodal

• Initial Temperature

• Structural, Thermal,

• Nodal

Coupled

Element Dimension

• Element Variable

• 1D 2D 3D

• 2D

• CID Distributed Load

• Structural, Coupled

Element Uniform

1D 2D 3D

• Contact

• Structural, Thermal,

Element Uniform

1D 2D 3D

Coupled • Convection

• Thermal, Coupled

• Element Uniform

• 2D 3D

• Element Variable • 2D 3D • Heat Flux

• Thermal, Coupled

• Element Uniform

• 2D 3D

• Element Variable • 2D 3D • Volumetric Flux

• Thermal, Coupled

• Heat Source

• Thermal, Coupled

Element Uniform

• 1D 2D 3D

• Nodal • Element Uniform

• 2D 3D

• Element Variable • 2D

Main Index

• Radiation

• Thermal, Coupled

Element Uniform

• Convective Velocity

• Thermal, Coupled

Nodal

• 2D 3D

46 Marc Preference Guide Loads and Boundary Conditions - Contact

Object • Potential

Analysis Type • Coupled

Type • Nodal • Element Variable

• Charge

• Coupled

Element Dimension • 2D

• Nodal • Element Uniform

• 2D 3D

• Element Variable • 2D • Voltage

• Coupled

Nodal

• Current

• Coupled

• Nodal

• Magnetization

• Coupled

• Element Uniform

• 2D 3D

• Element Variable

• 2D

• Element Uniform

Loads and boundary conditions can be placed directly on geometric or finite element entities. In both cases the loads and boundary conditions are written to the Marc input file and associated with finite element entities, either nodes or elements. Geometric entities in Patran are evaluated to determine the associated finite element entities. However, in Marc 2003 and greater, geometric entities can be written to the input file and the loads and boundary conditions associated directly to them. This is advantageous for adaptive remeshing. See Loads on Geometry for more details. Note:

The load magnitudes specified for any of the above load types should always be given as total loads for any given step or load case. The Marc Preference always writes loads to the Marc input file as total loads (not incremental loads) by using the parameter FOLLOW FOR,,1 in the input file. This has nothing to do with follower forces even though the flag is on this parameter. If the Use Tables toggle is ON, then this parameter is NOT written to specify total loads as total loads are assumed in this case.

Static Load Case Input This subordinate form appears when the Input Data button is selected and Static is the load case type. The load case type is set under the Load Cases application. See Load Cases. The information contained on this form will vary according to the selected Object. However, defined below is information that remains standard to this form.

Main Index

Chapter 2: Building A Model 47 Loads and Boundary Conditions - Contact

Note:

It is not advisable to mix both static and time dependent load cases together in a single analysis. Use either all static or all time dependent loading.

Time Dependent Load Case Input This subordinate form appears when the Input Data button is selected in the Loads and Boundary Conditions application and the load case is Time Dependent. The load case type is set under the Load Cases application. See Load Cases. The information contained on this form will vary according to the selected Object. However, defined below is information that remains standard to this form.

Main Index

48 Marc Preference Guide Loads and Boundary Conditions - Contact

Object Tables On the Static and Transient Input Data forms, these are areas where the load data values are defined. The data fields presented depend on the selected Object and Type. In some cases, the data fields also depend on the selected target element type. These object tables list and define the various input data which pertain to a specific selected object.

Main Index

Chapter 2: Building A Model 49 Loads and Boundary Conditions - Contact

Note:

The Analysis Type set on the Loads and BCs application form will determine which Objects are available to you. You can switch between Analysis Types without affecting any analysis setup or recognition of already defined LBCs.

Acceleration This input data creates the FIXED ACCE and the ACC CHANGE keyword options. All non-blank entries will generate prescribed accelerations with the FIXED ACCE option. Time dependent fields create multiple ACC CHANGE options. Currently the TABLE parameter and option in conjunction with a LOADCASE option for Marc 2003 or greater is not supported with the LBC. Input Data

Type

Analysis

Description

Translations (A1,A2,A3)

Nodal

Structural Coupled

Defines the prescribed translational acceleration vector. Components of the vector are entered in model length units.

Rotations (R1,R2,R3)

Nodal

Structural Coupled

Defines the prescribed rotational acceleration vector.

Caution:

Read caution notes for Displacements below

Displacement This input data creates the FIXED DISP and the DISP CHANGE keyword options. All non-blank entries will generate prescribed displacements with the FIXED DISP option. Time dependent fields create multiple DISP CHANGE options, or a TABLE parameter and option in conjunction with a LOADCASE option for Marc 2003 or greater.

Main Index

50 Marc Preference Guide Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Translations (T1,T2,T3)

Nodal

Structural Coupled

Defines the prescribed translational displacement vector. Components of the vector are entered in model length units. This vector is not transformed. The analysis coordinate frames of the nodes in the application region are changed to the analysis coordinate frame specified on this form.

Rotations (R1,R2,R3)

Nodal

Structural Coupled

Defines the prescribed rotational displacement vector. Components of the vector are entered in radians. This vector is not transformed. The analysis coordinate frames of the nodes in the application region are changed to the analysis coordinate frame specified on this form.

Use Sub. FORCDT

Nodal

Structural Coupled

If this toggle is ON, the FORCDT option is written. The list of nodes supplied in the 2nd data block of this option comes from the application regions list of nodes or associated nodes. For displacements, the FIXED DISP keyword is still written but with zero magnitudes for the specified degrees-offreedom.

Caution:

Patran always assumes there are six (6) degrees-of-freedom per node regardless of the element type. You must be cognizant of the actual degrees-of-freedom valid for a particular Marc element you want to use. For example, an axisymmetric shell (1D element) has only three valid degrees-of-freedom (axial (Z), radial (R) and rotational) but in Patran these would map to degrees-of-freedom 1, 2, and 4 (T1, T2, and R1 respectively). Elements 49 and 72 have midside nodes with only a single rotational dof, which would be considered the 4th (R1) dof in Patran.

Release This input data creates the RELEASE NODE keyword option. All non-blank entries will generate prescribed releases of previously prescribed displacements specified using the FIXED DISP option in a previous Load Step. Time dependent fields are not applicable. Release will also be ignored if included in a loadcase associated to the first Load Step. Only subsequent Load Steps can release node constraints. This option is not available when using the TABLE parameter (Use Tables is ON in the Job Parameters form) and option in conjunction with a LOADCASE option for Marc 2003 or greater. RELEASE NODE will not be written in this case. Instead, any releases should be done using the Select Load Case selection form.

Main Index

Chapter 2: Building A Model 51 Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Translations (T1,T2,T3)

Nodal

Structural Coupled

Defines the prescribed translational displacement vector that should be released. Any non-null value entered here will be used to indicate that that translational degree-offreedom is to be released.

Rotations (R1,R2,R3)

Nodal

Structural Coupled

Defines the prescribed rotational displacement vector that should be released. Any non-null value entered here will be used to indicate that that rotational degree-of-freedom is to be released.

Caution:

The same caution as that for Displacement is applicable for Release also.

Force This input data creates the POINT LOAD keyword option. Multiple POINT LOAD options are generated for the time dependent fields, or a TABLE parameter and option in conjunction with a LOADCASE option for Marc 2003 or greater.

Main Index

Input Data

Type

Analysis

Description

Force (F1,F2,F3)

Nodal

Structural Coupled

Defines the applied translational force vector with respect to the specified analysis coordinate frame. This vector is transformed from the specified analysis coordinate frame to the analysis coordinate frames of the nodes in the application region before it is written to the third card of the POINT LOAD option.

Moment (M1,M2,M3)

Nodal

Structural Coupled

Defines the applied rotational force vector with respect to the specified analysis coordinate frame. This vector is transformed from the specified analysis coordinate frame to the analysis coordinate frames of the nodes in the application region before it is written to the third card of the POINT LOAD option.

Use Sub. FORCDT

Nodal

Structural Coupled

If this toggle is ON, the FORCDT option is written. The list of nodes supplied in the 2nd data block of this option comes from the application regions list of nodes or associated nodes. In this case, no POINT LOAD options are written, only the FORCDT option in the Model Definition section.

52 Marc Preference Guide Loads and Boundary Conditions - Contact

Caution:

Elements 49 and 72 have midside nodes with only a single rotational dof, which would be considered the 4th (M1) dof in Patran.

Pressure This input data creates the DIST LOADS keyword option. Multiple DIST LOADS options are generated for the time dependent fields, or a TABLE parameter and option in conjunction with a LOADCASE option for Marc 2003 or greater. An exception to this is when the Element Variable type is chosen as described in the table below

Main Index

Input Data

Type

Analysis

Description

Top Surface Pressure

Element Uniform

Structural/2D Coupled/2D

Defines the top surface pressure on shell and/or plate elements which is directed inward when positive. The IBODY data field of the DIST LOADS option is set to two.

Bot Surface Pressure

Element Uniform

Structural/2D Coupled/2D

Defines the bottom surface pressure on shell and/or plate elements which is directed inward when positive. This value is subtracted from the element’s top surface pressure and the difference is entered in the DIST LOADS option.

Edge Pressure

Element Uniform

Structural/2D Coupled/2D

Defines the edge pressure on 2D solid elements which is directed inward when positive. The IBODY data field of the DIST LOADS option varies based on the element edges chosen in the application region. Top and/or bottom surface pressures cannot be used in the same application region as edge pressure.

Pressure

Element Uniform / Variable

Structural/3D Coupled/3D

Defines the face pressure on solid elements which is directed inward when positive. The IBODY data field of the DIST LOADS option varies based on the element faces chosen in the application region.

Chapter 2: Building A Model 53 Loads and Boundary Conditions - Contact

Input Data

Analysis

Description

Element Top, Bottom Surface or Edge Variable Pressure or Pressure

Structural/2D Coupled/2D

This is used for superplastic forming. Putting a value in for Top or Bottom simply specifies the direction. The IBODY data field of the DIST LOADS option is set to the appropriate value for nonuniform loading in the normal direction for the given element type. The magnitude that you specify is arbitrary and should be used for visualization purposes only. The value written to the DIST LOADS option is zero.

Use Sub. FORCEM

Structural Coupled

If this toggle is ON, the FORCEM user subroutine is used by placing the appropriate nonuniform IBODY code in field 1 of the 3rd data block of the DIST LOADS option. The magnitude of the pressure will be written but may be ignored as the definition of the pressure load is the function of the FORCEM routine.

Note:

Type

Element Variable

If the Use Sub. toggle is ON, it will flag the use of the user subroutine unless a superplastic forming analysis is detected, in which case it will be ignored.

Temperature / Temp (Thermal) This input data creates the CHANGE STATE keyword option for element uniform conditions or the POINT TEMP for nodal conditions. Multiple CHANGE STATE or POINT TEMP options are generated for time dependent fields. Or this creates the FIXED TEMPERATURE and the TEMP CHANGE keyword options for thermal analysis.

Main Index

Input Data

Type

Analysis

Description

Temperature

Element Uniform

Structural/1D Coupled/1D

Defines the temperature state variable for the axisymmetric shell, beam and truss elements. (INITIAL STATE / CHANGE STATE)

Temperature

Element Uniform

Structural/2D Coupled/2D

Defines the temperature state variable for the shell, plate, and 2D solid elements. (INITIAL STATE / CHANGE STATE)

Temperature

Element Uniform

Structural/3D Coupled/3D

Defines the temperature state variables for the solid elements. (INITIAL STATE / CHANGE STATE)

54 Marc Preference Guide Loads and Boundary Conditions - Contact

Main Index

Input Data

Type

Analysis

Description

Temperature

Nodal

Structural

Defines the point temperature (POINT TEMP) values for nodes. The stress-free temperature value may be entered by using the Initial Temperature option. You may not define a reference temperature (in Material properties) if POINT TEMPs are defined.

Temperature

Nodal

Thermal Coupled

Defines the prescribed temperature value. Multiple TEMP CHANGE option are generated for the time dependent fields, or in Marc 2003 or greater, the TABLE and LOADCASE options are used instead. Note that a blank appication region will release all temperatures is subsequent Load Steps.

Top Bottom Middle Temperature

Element Variable

Thermal Coupled

Same as above except allows for definition of temperature for the various degrees of freedom in shell elements in 3D analysis.

Use Subs. Element INITSV/NEWS Uniform V

Structural

If this toggle is ON, the INITSV/NEWSV routines are flagged by placing a 2 in the 2nd field of the 2nd data block of the INITIAL STATE and CHANGE STATE keywords. Data blocks 3 and 4 are then not used.

Use Sub. FORCDT

Thermal Coupled

If this toggle is ON, the FORCDT option is written. The list of nodes supplied in the 2nd data block of this option comes from the application regions list of nodes or associated nodes. For temperatures, the FIXED TEMPERATURE keyword is still written.

Nodal

Chapter 2: Building A Model 55 Loads and Boundary Conditions - Contact

Inertial Load This input data creates the DIST LOADS and ROTATION A keyword option. Multiple DIST LOADS options are generated for the time dependent fields, or TABLE and LOADCASE options are used for Marc 2003 or greater. ROTATION A is written only if present in first Load Step for non-Table format.

Main Index

Input Data

Type

Analysis

Description

Translational Acceleration (A1,A2,A3)

Element Uniform

Structural Coupled

Defines the gravitational acceleration vector with respect to the specified analysis coordinate frame. This vector is transformed into the global coordinate frame before it is written to the third card of the DIST LOADS option. The load type (field 1) on the same card is set to 102.

Rotational Velocity (w1,w2,w3)

Element Uniform

Structural Coupled

Defines the angular velocity vector in radians per unit of time in the analysis coordinate frame for centrifugal loading. The magnitude of this vector is squared and entered on the third card of the DIST LOADS option. The load type (field 1) on the same card is set to 100. The direction of the angular velocity vector and the origin of the analysis coordinate frame are respectively entered as the direction of and point along the rotation axis on the second card of the ROTATION A option.

Rotational Acceleration (a1,a2,a3)

Element Uniform

Structural Coupled

Not supported.

56 Marc Preference Guide Loads and Boundary Conditions - Contact

Initial Displacement This input data creates the INITIAL DISP keyword option. Time dependent fields are ignored. Input Data

Type

Analysis

Description

Translations (T1,T2,T3)

Nodal

Structural Coupled

Defines the initial translational displacement vector with respect to the specified analysis coordinate frame. This vector is transformed from the specified analysis coordinate frame to the analysis coordinate frames of the nodes in the application region before it is written to the third card of the INITIAL DISP option.

Rotations (R1,R2,R3)

Nodal

Structural Coupled

Defines the initial rotational displacement vector with respect to the specified analysis coordinate frame. This vector is transformed from the specified analysis coordinate frame to the analysis coordinate frames of the nodes in the application region before it is written to the third card of the INITIAL DISP option.

Use Sub. USINC

Nodal

Structural Coupled

If this toggle is ON, the use of the USINC routine is flagged by placing a -1 in the 1st field of the 2nd data block of the INITIAL DISP option. Data blocks 3/4 are not required if this is the case.

Initial Velocity This input data creates the INITIAL VEL keyword option. Time dependent fields are ignored. Input Data Translational Velocity (v1,v2,v3)

Main Index

Type Nodal

Analysis Structural Coupled

Description Defines the initial translational velocity vector with respect to the specified analysis coordinate frame. This vector is transformed from the specified analysis coordinate frame to the analysis coordinate frames of the nodes in the application region before it is written to the third card of the INITIAL VEL option.

Chapter 2: Building A Model 57 Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Rotational Velocity (w1,w2,w3)

Nodal

Structural Coupled

Defines the initial rotational velocity vector with respect to the specified analysis coordinate frame. This vector is transformed from the specified analysis coordinate frame to the analysis coordinate frames of the nodes in the application region before it is written to the third card of the INITIAL VEL option.

Use Sub. USINC

Nodal

Structural Coupled

If this toggle is ON, the use of the USINC routine is flagged by placing a -1 in the 1st field of the 2nd data block of the INITIAL VEL option. Data blocks 3/4 are not required if this is the case.

1D Pressure This input data creates the DIST LOADS keyword option. Multiple DIST LOADS options are generated for the time dependent fields, or the TABLE and LOADCASE options are used for Marc 2003 or greater. Input Data

Type

Analysis

Description

Pressure

Element Uniform

Structural / 1D Coupled / 1D

Defines pressure loading on 1D planar and axisymmetric shell elements using the DIST LOADS option. Element Types

1, 15, 89, 90 (axisymmetric shell) 5, 16, 45 (planar beam) IBODY = 0: Uniform in XY plane.

Note:

Main Index

If the curves or elements on which this 1D (planar) Pressure is applied are not in the XY plane, an error will be issued. In order for the program to determine this, the orientation system must be supplied in the Element Properties application for the given entities. The element property must exist before the load is allowed.

58 Marc Preference Guide Loads and Boundary Conditions - Contact

CID Distributed Load This input data creates the DIST LOADS or equivalent POINT LOAD keyword option. Multiple options are generated for the time dependent fields, or the TABLE and LOADCASE options are used for Marc 2003 or greater. Input Data

Type

Analysis

Description

Distributed Force (F1,F2,F3)

Element Uniform

Structural / 1D Coupled / 1D

Defines the applied translational distributed force vector with respect to the specified analysis coordinate frame. In general this provides the magnitudes (for each component) of the uniform load per unit length for 1D elements on the DIST LOADS option. a) Types 15, 16, 45, 89, 90: IBODY = 1: Uniform in X. IBODY = 2: Uniform in Y. b) Types 9, 13, 14, 25, 52, 64, 76, 77, 78, 79, 98: IBODY = 0 or 1: Uniform in X. IBODY = 1 or 2: Uniform in Y. IBODY = 2 or 3: Uniform in Z.

Distributed Force (F1,F2,F3)

Element Uniform

Structural Coupled 1D/2D/3D

These types of loads are converted to equivalent POINT LOAD options along the line of application depending on the element type to which they are applied for 2D and 3D elements.

Patran converts the distributed loads to equivalent POINT LOADs distributed to the nodes of the geometric selection in the input file. This is accomplished in the following manner: Let q(x) be the distributed load applied between x0 and xf. The resultant force Q is given as Q Z

xf

∫x 0 q ( x ) dx

The centroid xc of the distributed load between x0 and xf is given as M x c Z ----Q

where M is the magnitude of the net moment around x0 given by M Z

xf

∫x 0 x q ( x ) dx

Consider the problem where there are n element edges. Treating each of the n element edges as separate beam problems, each resultant force is calculated and the centroid along each edge. Then each element edge is treated as a static beam problem with the nodes acting as pinned supports on each beam end. Sum

Main Index

Chapter 2: Building A Model 59 Loads and Boundary Conditions - Contact

the loads from each beam solution at all nodes except the 0th and nth nodes since each node is shared by two element edges (beams). As an example: Consider the problem of a uniform load q(x) of 200 pounds/inches applied along n element edges, each one inch long. Then Q=200 pounds, M = 100 inch pounds, and x0 = 0.5 inch for each element edge. The static solution for each element edge (as a beam) is 100 pounds applied on each end node. This gives the expected solution of 100 pounds applied at the end nodes and 200 pounds applied at all internal nodes. Similar calculations are done for two dimensional cases. Convection This input data creates the FILMS keyword options. Multiple FILMS options are generated for the time dependent fields. Input Data

Type

Analysis

Description

Top Surf Convection

Element Uniform/ Variable

Thermal/2D Coupled/2D

Defines the top surface film coefficient on shell elements. The entry in the IBODY data field is set to five on the third card of the FILMS option.

Bot Surf Convection

Element Uniform/ Variable

Thermal/2D Coupled/2D

Defines the bottom surface film coefficient on shell elements. The entry in the IBODY data field is set to six on the third card of the FILMS option.

Edge Convection

Element Uniform/ Variable

Thermal/2D Coupled/2D

Defines the edge film coefficient on 2D solid elements. The entry in the IBODY data field of the FILMS option varies based on the element edges chosen in the application region. Top and/or bottom surface convections cannot be used in the same application region as edge convection.

Convection

Element Uniform/ Variable

Thermal/3D Coupled/3D

Defines the film coefficient on faces of solid elements. The entry in the IBODY data field of the FILMS option varies based on the element faces chosen in the application region.

Ambient

Element Uniform/ Variable

Thermal/2D/3D Coupled/2D/3D

Defines the sink temperature for the shell or 2D solid and 3D elements. This produces an entry on the third card in the FILMS option.

Temperature

Main Index

60 Marc Preference Guide Loads and Boundary Conditions - Contact

Heat Flux / Volumetric Flux This input data creates the DIST FLUXES keyword options.

Main Index

Input Data

Type

Analysis

Description

Top Surface Heat Flux

Element Uniform

Thermal/2D

Defines the top surface heat flux on shell elements. The IBODY data field of the DIST FLUXES option is set to five.

Bot Surface Heat Flux

Element Uniform

Thermal/2D

Defines the bottom surface heat flux on shell elements. The IBODY data field of the DIST FLUXES option is set to six.

Edge Heat Flux

Element Uniform

Thermal/2D

Defines the edge heat flux on 2D solid elements. The entry in the IBODY data field of the DIST FLUXES option varies based on the element edges chosen in the application region. Top and/or bottom surface heat fluxes cannot be used in the same application region as an edge heat flux.

Heat Flux

Element Uniform

Thermal/3D

Defines the heat flux on faces of solid elements or entire elements in the case of Volumetric Flux. The entry in the IBODY data field of the DIST FLUXES option varies based on the element faces chosen in the application region.

Top/Bottom Surface/Edge Heat Flux

Element Variable

Coupled 2D/3D

When doing a Coupled analysis, Marc generates internal heat due to plastic work hardening that will effect the results. This is done by placing 101 (IBODY) in the 1st field of the 3rd data block of the DIST FLUXES option. Only the Element Variable Heat Flux LBC will request this. The magnitude is arbitrary and should be entered as zero, but will be ignored by the analysis if provided.

Use Sub. FLUX Element Variable

Thermal Coupled

If this toggle is ON, the FLUX user subroutine is used by placing the appropriate nonuniform IBODY code in field 1 of the 3rd data block of the DIST FLUXES option. The magnitude of the load will be written but may be ignored as the definition of the pressure load is the function of the FLUX routine.

Chapter 2: Building A Model 61 Loads and Boundary Conditions - Contact

Heat Source This input data creates the POINT FLUX keyword options. Input Data

Type

Analysis

Description

Heat Source

Nodal

Thermal Coupled

Defines the applied nodal heat source. Multiple POINT FLUX options are generated for the time dependent fields.

Top Bottom Middle Heat Source

Element Variable

Thermal Coupled

Same as above except allows for heat source definition at the various degrees of freedom for shell elements in 3D analysis.

Use Sub. FORCDT

Nodal

Thermal Coupled

If this toggle is ON, the FORCDT option is written. The list of nodes supplied in the 2nd data block of this option comes from the application regions list of nodes or associated nodes. In this case, no POINT FLUX options are written, only the FORCDT option in the Model Definition section.

Initial Temperature This input data creates the INITIAL TEMP keyword options. Input Data

Type

Analysis

Description

Temperature

Nodal

Structural Thermal Coupled

Defines the initial nodal temperature. Time dependent fields are ignored.

Top Bottom Middle Temperature

Element Variable

Structural Thermal Coupled

Same as previous except allows for temperature definition at the various degrees of freedom for shell elements in 3D analysis.

Use Sub. USINC

Nodal

Structural Thermal Coupled

If this toggle is ON, the use of the USINC routine is flagged by placing a -1 in the 1st field of the 2nd data block of the INITIAL TEMP option. Data blocks 3/4 are not required if this is the case.

Radiation This LBC type produces no options in the Marc input file. However, radiation LBCs must be present in order to do view factor calculations (see Radiation Viewfactors). Once a view factor calculation has been done and the view factor file has been created through this operation, a radiation analysis can be flagged

Main Index

62 Marc Preference Guide Loads and Boundary Conditions - Contact

by referencing this file and submitted. Only the VIEW FACTOR option is included in the input file with this operation. Input Data

Type

Analysis

Description

Temp. at Infinity (top)

Element Uniform

Thermal/2D Coupled/2D

Used as input to the view factor file only. Generally used on 3D shell elements. This is the ambient temperature at infinity.

Temp. at Infinity (bottom)

Element Uniform

Thermal/2D Coupled/2D

Used as input to the view factor file only. Generally used on 3D shell elements. This is the ambient temperature at infinity. For shell elements, you can have two different ambient temperatures as seen from the top or bottom.

Temp. at Infinity (edge)

Element Uniform

Thermal/2D Coupled/2D

Used as input to the view factor file only. Generally used on 2D solid elements such as axisymmetric or plane strain. This is the ambient temperature at infinity.

Temp. at Infinity

Element Uniform

Thermal/3D Coupled/3D

Used as input to the view factor file only on 3D solid elements. This is the ambient temperature at infinity.

Convective Velocity This input data creates the VELOCITY and VELOCITY CHANGE keyword options. Multiple VELOCITY CHANGE options are generated for the time dependent fields.

Main Index

Input Data

Type

Analysis

Description

Velocity (V1,V2,V3)

Nodal

Thermal Coupled

Defines the convective velocity on the specified nodes by writing the VELOCITY option.

Use Sub. UVELOC

Nodal

Structural Thermal Coupled

If this toggle is ON, the use of the UVELOC routine is flagged by placing a -1 in the 1st field of the 2nd data block of the VELOCITY or VELOCITY CHANGE options. Data blocks 35 are not required if this is the case.

Chapter 2: Building A Model 63 Loads and Boundary Conditions - Contact

Potential This input data creates the FIXED EL-POT or FIXED MG-POT keyword option for electrostatic or magnetostatic analysis. This LBC is ignored if not applicable to the selected analysis type. Input Data

Type

Analysis

Description

Potetnial

Nodal

Coupled

Defines the electrostatic potential.

Top Bottom Middle Potential

Element Variable

Coupled

Same as previous except allows for potential definition at the various degrees of freedom for shell elements in 3D analysis.

Charge This input data creates the POINT CHARGE or DIST CHARGES keyword options for electrostatic analysis. This LBC is ignored if not applicable to the selected analysis type. Input Data

Type

Analysis

Description

Charge

Nodal

Coupled

Defines the electrostatic charge. Nodal definitions write the POINT CHARGE and Element Uniform definitions write the DIST CHARGES option.

Coupled

Same as previous except allows for charge definition at the various degrees of freedom for shell elements in 3D analysis. Writes the POINT CHARGE option.

Element Uniform Top Bottom Middle Charge

Element Variable

Voltage This input data creates the FIXED VOLTAGE keyword option for thermal-electrodynamic (Joule heating) analysis. This LBC is ignored if not applicable to the selected analysis type. Input Data

Type

Analysis

Description

Voltage

Nodal

Coupled

Defines the applied voltage.

Top Bottom Middle Voltage

Element Variable

Coupled

Same as previous except allows for voltage definition at the various degrees of freedom for shell elements in 3D analysis.

Current This input data creates the POINT CURRENT or DIST CURRENT keyword options thermalelectrodynamic (Joule heating) and other applicable analyses. This LBC is ignored if not applicable to the selected analysis type.

Main Index

64 Marc Preference Guide Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Current

Nodal

Coupled

Defines the applied current.

Coupled

Same as previous except allows for current definition at the various degrees of freedom for shell elements in 3D analysis.

Element Uniform Top Bottom Middle Current

Element Variable

Magnetization Creates the PERMANENT option in magnetostatic analysis. Input Data

Type

Analysis

Description

Remenance

Element Uniform

Coupled

Defines a permanent magnet for magnetostatic analysis (vector input).

Contact Defines deformable and rigid contact bodies, and creates certain data entries in the CONTACT and MOTION CHANGE keyword options. Other data entries in the CONTACT option are defined under the Analysis application when setting up a job for nonlinear static or nonlinear transient dynamic analysis. A CONTACT TABLE option is also supported; by default, all contact bodies initially have the potential to interact with all other contact bodies and themselves. This default behavior can be modified under the Contact Table form, located on the Solution Parameters form in the Analysis application when creating a Load Step. See Contact Parameters and Contact Table. Note:

For pure heat transfer analysis, the THERMAL CONTACT options is used instead of CONTACT.

The Application Region form for contact is used to select the contact bodies whether they be deformable or rigid. Deformable contact bodies are always defined as a list of elements or a list of elements associated to a geometric entity, the boundary of which defines the contact surface. Rigid bodies are translated as ruled surfaces or 3-noded patches (2D) or straight line segments (1D) if a mesh or geometry with an associated mesh is selected. Otherwise, if no mesh is associated with the selected geometry, the contact definition will be written as geometric NURB surfaces during translation. 2D meshed surfaces can use 4 or 8 noded quads, or 3 or 6 noded tri elements, however the mid-side nodes are unnecessary and ignored for the higher order elements.

Main Index

Chapter 2: Building A Model 65 Loads and Boundary Conditions - Contact

Caution: The line segments of a meshed rigid body will be translated only if they form a continuous sequence of 1D elements (i.e. no branches, and common nodes between adjoining elements). And the sequence of nodes must be open (i.e., the first node should be distinct from the last one). Note that a mesh of a closed loop composed of a single curve should not be equivalenced so as to make an open sequence of nodes. However, if the mesh used two curves, only one pair of common nodes should be equivalenced. Deformable Body

These input properties are defined for each deformable body defined on the CONTACT keyword option. They can be overridden if defined with non-zero values in the CONTACT TABLE. Also the SPLINE option for representing a deformable body with an analytical surface to improve accuracy is defined here Input Data

Type

Analysis

Description

Structural Coupled

Coefficient of static friction for this contact body. For contact between two bodies with different friction coefficients, the average value is used. Only available for Structural and Coupled analysis.

Structural Properties: Friction Coefficient (MU)

Element Uniform

Thermal Properties:

Main Index

Heat Transfer Coefficient to Environment

Element Uniform

Thermal Coupled

Heat transfer coefficient (film) to environment. This is only allowed for thermal or coupled analysis.

Environment Sink Temperature

Element Uniform

Thermal Coupled

Environment sink temperature. This is only allowed for thermal or coupled analysis.

Contact Heat Transfer Coefficient

Element Uniform

Thermal Coupled

Contact heat transfer coefficient (film). This is only allowed for thermal or coupled analysis.

Near Contact Heat Transfer Coefficient

Element Uniform

Thermal Coupled

Near Contact heat transfer coefficient (film). This is only allowed for thermal or coupled analysis. Requires that a tolerance distance be defined in the Contact Table. Heat fluxes have components of convection and radiation which are defined in the next properties.

Natural Convection Coefficient

Element Uniform

Thermal Coupled

Natural convetion coefficient used with near thermal contact. This is only allowed for thermal or coupled analysis.

Natural Convection Exponent

Element Uniform

Thermal Coupled

Natural convetion exponent used with near thermal contact. This is only allowed for thermal or coupled analysis.

66 Marc Preference Guide Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Surface Emissivity

Element Uniform

Thermal Coupled

Surface emissivity used with near thermal contact radiation component. This is only allowed for thermal or coupled analysis.

Distance Dependent Heat Transfer Coefficient

Element Uniform

Thermal Coupled

Distance dependent heat transfer coefficient used with near thermal contact. This is only allowed for thermal or coupled analysis.

Electrical Properties (only written in TABLE format): Conductivity

Element Uniform

Coupled

Electrical transfer coefficient to environment. Only used in Coupled analysis (Joule Heating).

Sink Voltage

Element Uniform

Coupled

Environment sink voltage. Only used in Coupled analysis (Joule Heating).

Contact Conductivity

Element Uniform

Coupled

Electrical transfer coefficient to environment. Only used in Coupled analysis (Joule Heating).

Near Contact Conductivity

Element Uniform

Coupled

Electrical transfer coefficient for near field behavior. Only used in Coupled analysis (Joule Heating).

Distance Dependent Conductivity

Element Uniform

Coupled

Separation distance dependent electrical transfer coefficient. Only used in Coupled analysis (Joule Heating).

Structural

By default a deformable contact body boundary is defined by its elements (Discrete). However, you can use an Analytic surface to represent the deformable body. This improves the accuracy for deformable-deformable contact analysis by describing the outer surface of a contact body by a spline (2D) or Coons surface (3D) description. This writes a SPLINE option to the input file.

Analytical Contact Definition: Boundary Type

Element Uniform

Thermal Coupled

MFD Increment

Element Uniform

Structural Thermal Coupled

Main Index

This places the number specified in the 2nd field of the 2nd data block of the SPLINE option. An MFD file will be written every n increments as specified by this number. This file can be viewed my Marc Mentat to ensure the spline or coon surface data is being properly generated to define the proper discontinuities.

Chapter 2: Building A Model 67 Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Select Discontinuities

Element Uniform

Structural

This is an optional input. The Analytic surface of a deformable body can be described by a spline (2D) or Coons surface (3D) and by default the entire outer surface will be included unless an Exclusion Region is selected. The exclusion region is a region of discontinuity where you don’t want a spline or coons surface fit. You may select either Geometry or FEM entities of the contact body to define these regions. For 2D analysis, the exlusion region consists of nodes that describe vertices through which a spline should not be fit. You select either individual nodes or geometric entities from which the associated nodes are extracted. For 3D analysis, the exlusion region consists of element edges across which a coons surface should not be fit. You select individual element edges or geometric curves/edges of surfaces/solids from which the associated element edges are extracted. You can set the Detect Discontinuities and give a feature angle if you wish the program to automatically detect these exclusion regions. Once the entities are determined, you may edit them as necessary.

Thermal Coupled

Auto Detect Discontinuities Feature Angle

Element Uniform

Structural Coupled

You can indicate for the Marc analysis to automatically detect the discontinuities by turning this toggle on and using the specified Feature Angle. This Feature Angle is also used by Patran if you click on the Detect Discontinuities button if you wish to view the discontinuity selection manually before submitting the job.

Contact Area Definition: Select Contact Area

Element Uniform

Structural Coupled

Main Index

You may define the nodes that are most likely to come into contact to speed up the compute time of the analysis when using contact. This writes the CONTACT NODE option to the input deck. The nodes associated to the entities selected are written. A node not included in this list that is part of the contact body may penetrate other bodies.

68 Marc Preference Guide Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Structural

For certain contact problems, you might wish to influence the decision regarding the deformable segment a node contacts. You can specify element edges for 2D and surfaces for 3D analysis to be excluded from the contacted bodies. This writes the EXLUDE option to the input deck. The segments to be excluded are written by extracting the nodes that define the edge or surface.

Exclusion Region: Select Exclusion Region

Element Uniform

Coupled

Rigid Body Motion Properties: Treat as Rigid

Element Uniform

Coupled

A deformable body in Coupled analysis can be treated as a simple rigid heat transfer body. In this case, many of the rigid body attributes, such as motion control can also be applied. See the input properties for Rigid Bodies below.

Rigid Body

These input properties are defined for each rigid body defined on the CONTACT keyword option. The input data form differs for 1D and 2D rigid bodies. One dimensional rigid surfaces are defined as beam elements, or as curves (which may be meshed with beam elements prior to translation) and used in 2D problems. The lines or beams must be in the global X-Y plane. Two dimensional rigid surfaces must be defined as Quad/4 or Tri/3 elements, or as surfaces (which may be meshed with Quad/4 or Tri/3 elements prior to translation) and are used in 3D problems. The elements will be translated as ruled surfaces if meshed or as NURB surfaces if not meshed in the Marc input file

Main Index

Input Data

Type

Analysis

Description

Flip Contact Side

Element Uniform

Structural Coupled 1D/2D

Upon defining each rigid body, Patran displays normal vectors or tic marks. These should point inward to the rigid body. In other words, the side opposite the side with the vectors is the side of contact. Generally, the vector points away from the body in which it wants to contact. If it does not point inward, then UNDO the definition of the rigid surface, turn this toggle ON, and create the rigid surface again. The direction of the inward normal will be reversed.

Symmetry Plane

Element Uniform

Structural Coupled 1D/2D

This specifies that the surface or body is a symmetry plane. This places a one (1) in the 3rd field of the 4th data block of the CONTACT option. It is OFF by default.

Chapter 2: Building A Model 69 Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Null Initial Motion

Element Uniform

Structural Coupled 1D/2D

This toggle is enabled only for Velocity and Position type of Motion Control. If it is ON, the intitial velocity, position, and angular velocity/rotation are set to zero in the CONTACT option regardless of their settings here (for increment zero).

Motion Control

Element Uniform

Structural Coupled 1D/2D

Motion of rigid bodies can be controlled in a number of different ways: velocity, position (displacement), or forces/moments.

Velocity (vector)

Element Uniform

Structural Coupled 1D/2D

For velocity controlled rigid bodies, define the X and Y velocity components for 2D problems or X, Y, and Z for 3D problems. Data is placed on MOTION CHANGE option.

Angular Velocity (rad/time)

Element Uniform

Structural Coupled 1D/2D

For velocity controlled rigid bodies, if the rigid body rotates, give its angular velocity in radians per time (seconds usually) about the center of rotation (global Z axis for 2D problems) or axis of rotation (for 3D problems). Data is placed on MOTION CHANGE option.

Velocity vs Time Field

Element Uniform

Structural Coupled 1D/2D

If a rigid body velocity changes with time, its time definition may be defined through a nonspatial field, which can then be selected via this widget. It will be scaled by the vector definition of the velocity as defined in the Velocity widget. The Angular Velocity will also be scaled by this time field. See the explanation below in Rigid Body Motion.

Displacement (vector)

Element Uniform

Structural Coupled 1D/2D

For position controlled rigid bodies, define the final X and Y position in global coordinates for 2D problems or X, Y, and Z for 3D problems. Data is placed on MOTION CHANGE option.

Angular Position (radians)

Element Uniform

Structural Coupled 1D/2D

For position controlled rigid bodies, if the rigid body rotates, give its final angular position in radians about the center of rotation (global Z axis for 2D problems) or axis of rotation (for 3D problems). Data is placed on MOTION CHANGE option.

Motion Control:

Main Index

70 Marc Preference Guide Loads and Boundary Conditions - Contact

Main Index

Input Data

Type

Analysis

Description

Displacement vs Time Field

Element Uniform

Structural Coupled 1D/2D

If a rigid body position changes with time, its time definition may be defined through a nonspatial field, which can then be selected via this widget. It will be scaled by the vector definition of the position as defined in the Displacement widget. The Angular Position will also be scaled by this time field. See the explanation below in Rigid Body Motion.

Rotation Element Reference Point Uniform

Structural Coupled 1D/2D

This is a point or node that defines the center of rotation of the rigid body. If left blank the rotation reference point will default to the origin. This is placed on the 5th data block of the CONTACT option. For Force/Moment driven bodies, this is the First Control Node.

Axis of Rotation

Element Uniform

Structural/2D Coupled/2D

For 2D rigid surfaces in a 3D problem, aside from the rotation reference point, if you wish to define rotation you must also specify the axis in the form of a vector. This is placed in the 6th data block of the CONTACT option. (Z-axis is the default: <0., 0., 1.>)

First Control Node

Element Uniform

Structural Coupled 1D/2D

This is for Force controlled rigid motion. It is the node to which the force is applied. A separate LBC must be defined for the force, but the application node must also be specified here. If both force and moment are specified, they must use different control nodes even if they are coincident. The node number is placed in the 6th field of the 4th data block of the CONTACT option. This node also acts as the center of rotation (Rotation Reference Point).

Second Control Node

Element Uniform

Structural Coupled 1D/2D

This is for Moment controlled rigid motion. It is the node to which the moment is applied, sometimes called the auxiliary node. A separate LBC must be defined for the moment, but the application node must also be specified here. If both force and moment are specified, they must use different control nodes even if they are coincident. The node number is placed in the 7th field of the 4th data block of the CONTACT option. The moment acts around the Rotation Reference Point, which is the First Control Node.

Chapter 2: Building A Model 71 Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Approach Velocity

Element Uniform

Structural Coupled

This defines the approach velocity of rigid bodies to position them in contact before the analysis proceeds. This is useful mostly when using load controlled rigid bodies. This is generally written to the 6th data block of the CONTACT option for VERSION, 10 formated files and is only valid for MSC.Marc 2003 or greater.

Approach Angular Velocity

Element Uniform

Thermal Coupled

See Approach Velocity.

Number of Subdivision

Element Uniform

Structural Thermal Coupled

In the NURB definition portion of the CONTACT option, these data specify the number of subdivision in the U, V directions for surface data and the number of subdivisions for curves or trimming curves.

Structural Coupled 1D/2D

Coefficient of static friction for this contact body. For contact between two bodies with different friction coefficients the average value is used. This is placed in the 5th, 6th, or 7th data block of the CONTACT option depending on the dimensionality of the problem.

Structural Properties: Friction Coefficient (MU)

Element Uniform

Thermal Properties: Heat Transfer Coefficients, Convection, Emissivity

Element Uniform

Thermal/ Coupled 1D/2D

All of these heat transfer properties are the same as defined for deformable bodies above.

Body Temperature

Element Uniform

Thermal/ Coupled 1D/2D

Body temperature. Only necessary for coupled analysis. This is placed in the 5th, 6th, or 7th data block of the CONTACT option depending on the dimensionality of the problem.

Electrical Properties (only written in TABLE format):

Main Index

Body Voltage

Element Uniform

Coupled

Rigid body voltage. Only used in Coupled analysis (Joule Heating).

Contact Conductivity

Element Uniform

Coupled

Electrical transfer coefficient to environment. Only used in Coupled analysis (Joule Heating).

72 Marc Preference Guide Loads and Boundary Conditions - Contact

Input Data

Type

Analysis

Description

Near Contact Conductivity

Element Uniform

Coupled

Electrical transfer coefficient for near field behavior. Only used in Coupled analysis (Joule Heating).

Distance Dependent Conductivity

Element Uniform

Coupled

Separation distance dependent electrical transfer coefficient. Only used in Coupled analysis (Joule Heating).

Note:

Main Index

The order in which you see rigid and deformable bodies in the contact table and written to the Marc input file is by alphabetical order with deformable bodies listed first and not in the order in which they were created. If you need to reorder them, you can do so by renaming them under the Modify action in the Loads/BCs application.

Chapter 2: Building A Model 73 Loads and Boundary Conditions - Contact

Rigid Body Motion

The motion of rigid bodies is defined under this contact LBC. The motion can be specified as velocity driven, position driven, or force/moment driven. In the latter case, you must define your force and/or moment via the appropriate LBC and apply it to a node which is then referenced as the control node when defining the rigid body. The first control node is for force and the second is for moment. These nodes must be different. For velocity or position driven rigid bodies, you define a vector describing the velocity or position. Each rigid body can only reference a single vector to describe this motion plus another scalar value describing the angular velocity or position (in radians/sec. or radians, respectively). It is possible to describe the velocity or position via a time varying field. You may use two different field dimensionalities to describe this motion. A one dimensional nonspatial field may be selected in which case all components of the velocity or position vector are scaled by this time varying field, including the angular velocity/position. This does not allow separate control of each component and is limited in this respect. If you must have separate time varying control for all components of the velocity or position, then you must use a 2D nonspatial field where the independent variables are time(t) and velocity(v) or time(t) and displacement(u). This allows you to define time in the first column, the v1,v2,v3 or u1,u2,u3 in the 2nd through 3rd columns and the angular velocity/position in the 4th column. If a particular component does not move, you must leave that column of the field blank. The header values of the velocity or position columns must be input in increasing values, however these values are ignored. Please see Non-Spatial Fields for an example. Note:

You can preview the motion with the Preview Motion button on the main form. If this toggle is ON, the selected rigid body will move according to the motion definition. This is useful to determine that the motion control has been defined properly. This works with time dependent fields also.

The Preview Motion as mentioned in the note above issues this PCL command: lbc_animate_rb_motion( lbc_name, start_time, end_time, num_frames, time_delay)

where:

Main Index

lbc_name

Name of the contact body in double quotes, e.g., “rigid_body”

start_time

Time you wish motion to start. If not defined by a time dependent field, this should be set to zero.

end_time

Time you wish motion to end. If not defined by a time dependent field, this should get set to one.

num_frames

The number of frames you wish to see animated. The more you specify the smoother the animation will look but the longer it will take.

time_delay

The time delay between dispaly of individual frames in milliseconds.

74 Marc Preference Guide Material Library

Material Library The Materials application defines Marc materials which are later associated to the elements of the model in the Element Properties application described in the next section, Element Properties.

Main Index

Chapter 2: Building A Model 75 Material Library

The following tables outlines the available options that can be created for Structural, Thermal, and Coupled analyses. Isotropic/Orthotropic/Anisotropic Constitutive Model

2D Conditions

Method

• Elastic

• Plane Stress / Thin Shell

• Entered Values

• Plane Strain / Axisymmetric

• User Subs.

ANELAS ANEXP (Anisotropic Only)

• Thick Shell • Axisymmetric with Twist • Axisymmetric Shell • None (Isotropic and 3D cases)

Constitutive Model

Failure Criterion

Failure Option

• Failure

• Hill

• Default

• Failure 2

• Hoffman

• Progressive Failure

• Failure 3

• Tsai-Wu • Maximum Strain • Maximum Stress • User Sub. UFAIL

Constitutive Model • Hyperelastic (Isotropic

Only)

Model

Domain Type

• Neo-Hookean

• Time

• Mooney-Rivlin

• Frequency

Number of Terms • 1

• Full 3rd Order • Ogden

• Time

• 1-6

• Time

• 1

• Foam • Arruda-Boyce • Gent • User Sub.

(UELASTOMER)

• Ogden • Foam-Invariants • Foam-Principals • Foam-Invariants (Deviatoric Split) • Foam-Principals (Deviatoric Split)

Main Index

76 Marc Preference Guide Material Library

Isotropic/Orthotropic/Anisotropic Constitutive Model

Thermal Expansion

Stress-Strain Law

• Hypoelastic

• Entered Values

• User Sub.

(Isotropic Only)

• User Sub. ANEXP

HYPELA • User Sub.

HYPELA2 (Grad/Rot) • User Sub.

HYPELA2 (Grad/Str) • User Sub.

HYPELA2 (All Input) • User Sub. UBEAM

Constitutive Model

Shift Function

• Viscoelastic (Isotropic,

• No Function

Orthotropic only)

• Williams-Landel-Ferry • Power Series Expansion • Narayanaswamy Model • User Sub. TRSFAC

Constitutive Model

Method

• Creep

• Power Law - Piecewise • User Sub.CRPLAW

Constitutive Model • Dmping

Constitutive Model

Method

• Thermal

• Entered Values • User Subs. ANKOND ORIENT

Constitutive Model

Memory Model

• Shape Memory

• Mechanical (Auricchio)

(Isotropic only)

Main Index

• Thermal Mechanical

Chapter 2: Building A Model 77 Material Library

Isotropic/Orthotropic/Anisotropic Constitutive Model

Damage Type

Damage Model

• Damage

• Elastic/Plastic

• No Nucleation • Plastic Strain

Control Nucleation • Stress Control

Nucleation • User Sub.

UVOIDN • Elastomer (Rubber)

(Isotropic Only)

• Additive

Decomposition • Multiplicative

Decompostion • User Sub.

UELDAM • Simple

(Isotropic Only)

• Yield- User Sub.

UDAMAG • Yield/Youngs Mod.

(UDAMAG) Constitutive Model

Method

• Cracking (Isotropic

• Entered Values

only)

• User Subs. UCRACK...

Constitutive Model

Method

• Forming Limit

• Fitted • Predicted • Table

Constitutive Model

Method

• Grain Size (Isotropic

• Yada

only) Constitutive Model

Model

• Soil

• Linear

(Isotropic / Orthotropic only)

• Cam Clay • User Sub.HYPELA

Constitutive Model

Method

• Powder

• Entered Values

(Isotropic only)

Main Index

• User Sub. UGRAIN

• User Sub. UPOWDR

78 Marc Preference Guide Material Library

Isotropic/Orthotropic/Anisotropic Constitutive Model

Model

• Electrostatic

• Entered Values

(Isotropic / Orthotropic Only) • Electrodynamic

• Entered Values

(Isotropic / Orthotropic / Anisotropic) • Magnetostatic (p. 109)

• Entered Values • User Sub UMU

• Piezoelectric (p. 109)

• Stress Based • Strain Based

Main Index

Chapter 2: Building A Model 79 Material Library

Isotropic/Orthotopic/Anisotropic Constitutive Model • Plastic

Type • Elastic-

Plastic

Hardening Rule • Isotropic

Yield Criteria • von Mises

• Kinematic • Hill Yield • Combined • Barlat • Linear Mohr-Coulomb

Strain Rate Method • Piecewise

Linear • Cowper-

Symonds

(Isotropic Only) • Parabolic Mohr-Coulomb

(Isotropic Only) • Buyukozturk Concrete

(Isotropic Only) • Oak Ridge National Lab • 2-1/4 Cr-Mo ORNL • Reversed Plasticity

ORNL • Full Alpha Reset ORNL • Generalized Plasticity • Power Law (Isotropic only) • Rate Power Law (Isotropic only) • Johnson-Cook (Isotropic only) • Kumar (Isotropic only) • Chaboche (Isotropic only) • Viscoplastic (UVSCPL) (Isotropic, Orthotropic only)

Main Index

80 Marc Preference Guide Material Library

Isotropic/Orthotopic/Anisotropic Constitutive Model • Plastic

(Cont.)

Type • Perfectly

Hardening Rule • None

Plastic

Yield Criteria • von Mises • Linear Mohr-Coulomb • Hill Yield • Barlat

Strain Rate Method • Piecewise

Linear • Cowper-

Symonds

• Linear Mohr-Coulomb

(Isotropic Only) • Parabolic Mohr-Coulomb

(Isotropic Only) • Buyukozturk Concrete

(Isotropic Only) • Oak Ridge National Lab • 2-1/4 Cr-Mo ORNL • Reversed Plasticity

ORNL • Full Alpha Reset ORNL • Generalized Plasticity • Rigid-Plastic • Power Law

(Isotropic only)

• Rate Power Law • Johnson-Cook • Kumar • Piecewise • None

Linear

• Piecewise

Linear • Cowper-

Symonds

Material Input Properties This is an example of one of many Input Properties forms that can appear when defining material properties. There is a Constitutive Model plus other optional selections followed by places for input of specific property parameters.

Main Index

Chapter 2: Building A Model 81 Material Library

For each material type, see the following pages: Isotropic (p. 81), 2D Orthotropic (p. 101), 3D Orthotropic (p. 101), 2D Anisotropic (p. 81), 3D Anisotropic (p. 81), or Composite (p. 110). For thermal material property definitions see (p. 94). Note:

For Coupled analysis, the thermal properties are also presented along with the structural. The thermal properties are listed in Thermal - Isotropic / Orthotropic / Anisotropic.

Elastic - Isotropic / Orthotropic / Anisotropic This input data creates the ISOTROPIC and INITIAL STATE keyword options.

Main Index

82 Marc Preference Guide Material Library

Elastic - Isotropic Method (Coupled only)

User Subs. ANKOND ORIENT - writes a 1 to the 4th field of the 3rd datablock of the ISOTROPIC option. Entered Values allows for the properties in this table to be entered.

Elastic Modulus

Defines the elastic modulus. It is entered in the first data field on the fourth card of the ISOTROPIC option. This property is generally required. May vary with temperature via a defined material field and placed on 4b data block of the TEMPERATURE EFFECTS option.

Poisson’s Ratio

Defines the Poisson’s ratio. It is entered in the second data field on the fourth card of the ISOTROPIC option. This property is generally required. May vary with temperature via a defined material field and placed on 5b data block of the TEMPERATURE EFFECTS option.

Density

Defines the mass density. It is entered in the third data field on the fourth card of the ISOTROPIC option. This property is optional.

Coefficient of Thermal Expansion

Defines the instantaneous coefficient of thermal expansion. This is entered in the fourth data field on the fourth card of the ISOTROPIC option. This property is optional. May vary with temperature via a defined material field and placed on 6b data block of the TEMPERATURE EFFECTS option.

Reference Temperature

Defines the reference temperature for the thermal expansion coefficient. It is entered in the first data field on the fourth card of the INITIAL STATE option. This property is optional. When defining temperature dependent properties, this is the reference temperature from which values will be extracted or interpolated for the WORK HARD and STRAIN RATE options. See note below.

Cost per Unit Volume

For design optimization, entered on the 7th field of the 4th data block of the ISOTROPIC option.

Cost per Unit Mass

For design optimization, entered on the 8th field of the 4th data block of the ISOTROPIC option.

Latent Heat vs Solidus Temp.

Both of these should be present. If one is missing you must treat all the temperature values as zero for the missing one. When both are present, they must reference Temperature material fields and they must all have exactly the same number of latent heats in them (with the same values). For Coupled analysis, the TEMPERATURE EFFECTS option is written with the values in block 11b and the number of latent heats in field 9 of block 2b.

Latent Heat vs Liquidus Temp. (Coupled only)

Main Index

Description

Chapter 2: Building A Model 83 Material Library

This input data creates the ORTHOTROPIC and INITIAL STATE keyword options. The required properties vary based on dimension and element type which for a 2D Orthotropic option can be set to either Plane Stress/Thin Shell, Plane Strain/Axisymmetric, Thick Shell, Axisymmetric with Twist, or Axisymmetric Shell. Elastic - Orthotropic

Main Index

Description

Method (Coupled only)

User Subs. ANKOND ORIENT - writes a 1 to the 4th field of the 3rd datablock of the ORTHOTROPIC option. Entered Values allows for the properties in this table to be entered.

Elastic Modulus 11/22/33

Defines the elastic moduli in the element’s coordinate system. They are entered in the first through third data fields on the fourth card of the ORTHOTROPIC option. This is required data. May vary with temperature via a defined material field and placed on 5b, 6b, and 7b data blocks of the ORTHO TEMP option.

Poisson’s Ratio 12/23/31

Defines the Poisson’s ratios relative to the element’s coordinate system. They are entered in the fourth through sixth data fields on the fourth card of the ORTHOTROPIC option. This is required data. May vary with temperature via a defined material field and placed on 8b, 9b, and 10b data blocks of the ORTHO TEMP option.

Shear Modulus 12/23/31

Defines the shear moduli relative to the element’s coordinate system. They are entered in the first through third data fields on the fifth card of the ORTHOTROPIC option. This is required data. May vary with temperature via a defined material field and placed on 11b, 12b, and 13b data blocks of the ORTHO TEMP option.

Coefficient of Thermal Expansion 11/22/33

Defines the instantaneous coefficients of thermal expansion relative to the element’s coordinate system. They are entered in the fourth through sixth data fields on the fifth card of the ISOTROPIC option. These properties are optional. This is required data. May vary with temperature via a defined material field and placed on 14b, 15b, and 16b data block of the ORTHO TEMP option.

Reference Temperature

Defines the reference temperature for the thermal expansion coefficient. It is entered in the first data field on the fourth card of the INITIAL STATE option. When defining temperature dependent properties, this is the reference temperature from which values will be extracted or interpolated for the WORK HARD and STRAIN RATE options. See note below.

Density

Defines the mass density which is an optional property. It is entered in the seventh data field on the fourth card of the ORTHOTROPIC option.

84 Marc Preference Guide Material Library

Elastic - Orthotropic

Description

Cost per Unit Volume

For design optimization, entered on the 7th field of the 5th data block of the ORTHOTROPIC option.

Cost per Unit Mass

For design optimization, entered on the 8th field of the 5th data block of the ORTHOTROPIC option.

Latent Heat vs Solidus Temp.

Both of these should be present or none. If one is missing the temperature values are treated as zero for the missing one. When both are present, they must reference Temperature material fields and they must all have exactly the same number of latent heats in them (with the same values). For Coupled analysis, the TEMPERATURE EFFECTS option is written with the values in block 11b and the number of latent heats in field 9 of block 2b.

Latent Heat vs Liquidus Temp. (Coupled only)

This input data creates the ANISOTROPIC and INITIAL STATE keyword options. The required properties vary based on dimension and element type which for a 2D Anisotropic option can be set to either Plane Stress/Thin Shell, Plane Strain/Axisymmetric, Thick Shell, Axisymmetric with Twist, or Axisymmetric Shell. Elastic - Anisotropic

Main Index

Description

Method

User Subs. ANELAS ANEXP ...- writes a 1 to 4th field of 3rd datablock of the ANISOTROPIC option - datablocks 4a-f not written. Entered Values allows for the properties in this table to be entered.

Stress-Strain Matrix, Cij

Defines the upper right portion of the symmetric stress-strain matrix relative to the element’s coordinate system. They are entered on the 4a, 4b and 4c card of the ANISOTROPIC option.

Coefficient of Thermal Expansion 11/22/33/12/23/31

Defines the instantaneous coefficients of thermal expansion relative to the element’s coordinate system. They are entered on the 4d card of the ANISOTORPIC option, and are optional properties.

Reference Temperature

Defines the reference temperature for the thermal expansion coefficient. It is entered in the first data field on the fourth card of the INITIAL STATE option. When defining temperature dependent properties, this is the reference temperature from which values will be extracted or interpolated for the WORK HARD and STRAIN RATE options. See note below.

Density

Defines the mass density which is an optional property. It is entered in the fourth data field on the fourth card of the ANISOTROPIC option.

Chapter 2: Building A Model 85 Material Library

Elastic - Anisotropic

Description

Cost per Unit Volume

For design optimization, entered on the 7th field of the 4th data block of the ANISOTROPIC option.

Cost per Unit Mass

For design optimization, entered on the 8th field of the 4th data block of the ANISOTROPIC option.

Latent Heat vs Solidus Temp.

Both of these should be present. If one is missing you must treat all the temperature values as zero for the missing one. When both are present, they must reference Temperature material fields and they must all have exactly the same number of latent heats in them (with the same values). For Coupled analysis, the TEMPERATURE EFFECTS option is written with the values in block 11b and the number of latent heats in field 9 of block 2b.

Latent Heat vs Liquidus Temp. (Coupled only)

Note:

Note on reference temperature. If the reference temperature is left blank, zero is assumed. If the reference temperature does not fall between temperature values defined for work hardening or strain rate, the highest or lowest values will be used depending on whether the reference temperature is greater or lower than the given temperature range. If it falls inbetween, then values are interpolated. For Structural analysis, if Nodal LBC Temperatures (POINT TEMP) also exist then the INITIAL STATE will not be written since this is incompatible.

Failure - Isotropic / Orthotropic / Anisotropic This input data creates the FAIL DATA option. The first data field of the fourth card is set to either HILL, HOFFMAN, TSAI-WU, MX STRAIN (maximum strain), MX STRESS (maximum stress) or User Sub. UFAIL. A number of the following input properties will appear depending on the material type and options set. Note that there are three Failure constitutive models: Failure, Failure 2, and Failure 3. This means that you can have up to three failure criteria per material model

Main Index

86 Marc Preference Guide Material Library

.

Failure Criteria Hill, Hoffman, Tsai-Wu, Maximum Stress/Strain

Description

Failure Option

Progressive Failure - writes a one (1) in the 3rd field of the 3rd data block of the FAIL DATA option for each criterion defined with this option set.

Max Tensile Stress X, Y & Z

Defines the tension stress (or strain) limits in the element’s coordinate system. 2nd, 4th and 6th fields of 4th datablock of FAIL DATA option, respectively.

Max Compressive Stress X, Y & Z

Defines the compression stress (or strain) limits in the element’s coordinate system. 3rd, 5th, and 7th field of 4th datablock of FAIL DATA option. Absolute values are used.

Max Shear Stress XY, YZ, ZX

Defines the shear stress (or strain) limits. 1st, 2nd and 3rd fields of 5th datablock of FAIL DATA option, respectively.

Failure Index

4th field of 5th datablock of FAIL DATA option.

Interactive Term XY, YZ, & ZX

Defines the stress interaction parameters. 5th, 6th, and 7th fields of 5th datablock of FAIL DATA option.

Note:

When User Sub. UFAIL is used, no input data is necessary and the word UFAIL is written in the 4th data block of the FAIL DATA option.

Hyperelastic - Isotropic The following Hyperelastic models can be created. Caution:

Main Index

If one of these constitutive models exists and is active, the Elastic or Plastic constitutive models must be turned off (made inactive) otherwise ISOTROPIC, WORK HARD and MOONEY or some other hyperelastic option will be written to the input file which will cause an incompatibility in the analysis.

Chapter 2: Building A Model 87 Material Library

Neo-Hookean, Mooney-Rivlin, Full 3rd Order Invariant Time Domain

Description

Strain Energy Function, C10, C01, C11, C20, C30

Strain energy densities as a function of the strain invariants in the material. Creates MOONEY option; 1st, 2nd, 5th, 6th, and 7th fields of 4th data block, respectively. May vary with temperature via a defined material field and placed on 4b data block of the TEMPERATURE EFFECTS option.

Density

Defines the mass density which is an optional property. It is entered in the third data field on the fourth card of the MOONEY option.

Coefficient of Thermal Expansion

Defines the instantaneous coefficient of thermal expansion. This is entered in the fourth data field on the fourth card of the MOONEY option. This property is optional. May vary with temperature via a defined material field and placed on 6b data block of the TEMPERATURE EFFECTS option.

Bulk Modulus

8th field of 4th data block of MOONEY option.

Reference Temperature

Defines the reference temperature for the thermal expansion coefficient. It is entered in the first data field on the fourth card of the INITIAL STATE option.

For Neo-Hookean, Mooney-Rivlin and Full 3rd Order in the Frequency Domain the additional inputs are: Neo-Hookean Frequency Domain φ 0, φ 1, φ 2, φ 11, φ 12, φ 21, φ 22 ,

Imaginary

Ogden

Main Index

Real and

Description Creates PHI-COEFFICIENTS option. One PHICOEFFICIENTS option is created for each pair of real and imaginary PHIs that has input. Input is a material field of frequency versus value. This frequency, real and imaginary phi coefficients are entered into the 1st, 2nd, and 3rd fields of the 3rd data block respectively. Description

Bulk Modulus K

Creates OGDEN option; 1st field of 4th data block.

Density

2nd field of 4th data block of OGDEN option.

Coefficient of Thermal Expansion

3rd field of 4th data block of OGDEN option.

Reference Temperature

Creates INITIAL STATE option. Defines the reference temperature for the thermal expansion coefficient.

88 Marc Preference Guide Material Library

Ogden Modulus 1

1st field of 6th data block of OGDEN option.

Exponent 1

2nd field of 6th data block of OGDEN option.

Note:

Modulus 1 and Exponent 1 will repeat for the Number of Terms and will increment as such, e.g., Modulus 2, Exponent 2 - Modulus 3, Exponent 3, etc. Same comment applies to FOAM option for repeating terms.

Foam

Description

Density

Creates FOAM option; 2nd field of 4th data.

Coefficient of Thermal Expansion

3rd field of 4th data block of FOAM option.

Reference Temperature

Creates INITIAL STATE option. Defines the reference temperature for the thermal expansion coefficient.

Modulus 1

1st field of 6th data block of FOAM option.

Deviatoric Exponent 1

2nd field of 6th data block of FOAM option.

Volumetric Exponent 1

3rd field of 6th data block of FOAM option.

Arruda-Boyce

Main Index

Description

Description

NKT

Creates the ARRUDBOYCE option: 1st field of 4th data block. May vary with temperature via a defined material field and placed on 4b data block of the TEMPERATURE EFFECTS option.

Chain Length

2nd field of 4th data block of ARRUDBOYCE option. May vary with temperature via a defined material field and placed on 5b data block of the TEMPERATURE EFFECTS option.

Bulk Modulus

5th field of 4th data block of ARRUDBOYCE option.

Density

3rd field of 4th data block of ARRUDBOYCE option.

Coefficient of Thermal Expansion

4th field of 4th data block of ARRUDBOYCE option.

Reference Temperature

Creates INITIAL STATE option. Defines the reference temperature for the thermal expansion coefficient.

Chapter 2: Building A Model 89 Material Library

Gent

Description

Tensile Modulus

Creates the GENT option: 3rd field of 4th data block. May vary with temperature via a defined material field and placed on 4b data block of the TEMPERATURE EFFECTS option.

Maximum 1st Invariant

4th field of 4th data block of GENT option. May vary with temperature via a defined material field and placed on 5b data block of the TEMPERATURE EFFECTS option.

Bulk Modulus

5th field of 4th data block of GENT option.

Density

1st field of 4th data block of GENT option.

Coefficient of Thermal Expansion

2nd field of 4th data block of GENT option.

Reference Temperature

Creates INITIAL STATE option. Defines the reference temperature for the thermal expansion coefficient.

User Sub. UELASTOMER

Description

Domain Type

The User Sub. UELASTOMER can be used with the Ogden or Foam model. If Ogden is selected, this places a 3 in the 3rd field of the 3rd datablock of the OGDEN option. If a Foam model is selected, it places a 1, 2, 3, or 4, respectively, in the 4th field of the 3rd datablock of the FOAM option. No terms are required if this user subroutine is selected for either Ogden or Foam.

Bulk Modulus K

Creates OGDEN option; 1st field of 4th data block.

Density

2nd field of 4th data block of OGDEN option. OR Creates FOAM option; 2nd field of 4th data.

Coefficient of Thermal Expansion

3rd field of 4th data block of OGDEN option. OR 3rd field of 4th data block of FOAM option.

Reference Temperature

Creates INITIAL STATE option. Defines the reference temperature for the thermal expansion coefficient.

Note:

Marc may force you to use a Herrmann formulated element when using some Hyperelastic constitutive models.

Hypoelastic - Isotropic The following Hypoelastic models can be created. The HYPOELASTIC option is written to the input file. This constitutive model requires the use of user subroutines as explained below.

Main Index

90 Marc Preference Guide Material Library

Hypoelastic

Description

Thermal Expansion

User Sub. ANEXP: This places a 1 in 2nd field of the 3rd data block of the HYPOELASTIC option. Otherwise it is zero (default).

Stress-Strain Law

User Sub. HYPELA or UBEAM flags use of the HYPELA or UBEAM user subroutines which is default and a zero is placed in the 3rd field of the 3rd data block of the HYPOELASTIC option. If HYPELA2 is selected, the 3rd field is set according to Rotation (Grad/Rot), Stretch Ratio (Grad/Str) or Both (All Input) which puts a 1, 2, or 3, respectively in the 3rd field of the 3rd data block.

Density

Defines the mass density which is an optional property. It is entered in the 1st data field on the fourth card of the HYPOELASTIC option and in the 6th field for Coupled or Thermal analysis.

Coefficient of Thermal Expansion

Defines the instantaneous thermal expansion coefficient which is an optional property. It is entered in the 2nd data field on the fourth card of the HYPOELASTIC option.

Conductivity

Defines the thermal conductivity which is an optional property. It is entered in the 3rd data field on the fourth card of the HYPOELASTIC option.

Specific Heat

Defines the specific heat which is an optional property. It is entered in the 4th data field on the fourth card of the HYPOELASTIC option.

Reference Temperature

Defines the reference temperature for the thermal expansion coefficient. It is entered in the first data field on the fourth card of the INITIAL STATE option.

Emissivity

Defines the emissivity which is an optional property. It is entered in the 7th data field on the fourth card of the HYPOELASTIC option.

A TEMPERATURE EFFECTS option is written for items above that accept temperature dependent field references. Viscoelastic - Isotropic / Orthotropic This input data creates the VISCELPROP, VISCELMOON, VISCELOGDEN, or VISCELORTH options. The Prony series are defined in Fields - Tables as material properties with time (relaxation time) as their independent variable and then selected here as input properties. All inputs must have the same number of time points (at the same times) in the referenced fields. The following equations may be useful when creating the Prony series for the bulk and shear moduli: K Z E ⁄ ( 3 ( 1 Ó 2 v ) ) G Z E ⁄ (2(1 H v) ) This also supports the SHIFT FUNCTION option for Thermo-Rheologically simple viscoelastic

Main Index

Chapter 2: Building A Model 91 Material Library

materials. The SHIFT FUNCTION is written for ISOTROPIC, ORTHOTROPIC, MOONEY, OGDEN, ARRUDA-BOYCE, & GENT models if present in the defined material.

Main Index

Viscoelastic - Isotropic

Description

Shift Function

Enters a 1, 2, 3, or -1 in the 2nd field of the 3rd data block of SHIFT FUNCTION to specify the type of function: WilliamsLandel-Ferry, Power Serires, Narayanaswamy, User Sub. TRSFAC. If the latter, no other data blocks are required. Input properties for the different shift functions are listed in this table.

Shear Constant

If a material field of time vs. value is supplied, will create a VISCELPROP option. This is valid when an Elastic and/or Plastic constitutive model is present. Fills out 1st and 2nd fields of 4th data block for the number of terms present in the field.

Bulk Constant

Same as above. Fills out 3rd and 4th fields of 4th data block for the number of terms present in the field. (Field code 5)

Energy Function Multiplier

Defines the duration effect on the hyperelastic model as a multiplier to the strain energy density function. If a material field of time vs. value is supplied, will create a VISCELMOON option. This is valid when a Hyperelastic constitutive model for Neo-Hookean, Mooney-Rivlin, Full 3rd Order, Arruda-Boyce, or Gent is present. Fills out the 4th data block for the number of terms present in the field. (Field code 5)

Deviatoric Multiplier

If a material field of time vs. value is supplied, will create a VISCELOGDEN option. This is valid when a Hyperelastic constitutive model of Ogden is present. Fills out 1st and 2nd fields of 4th data block for the number of terms present in the field. (Field code 5)

Dilatational Multiplier

Same as above. Fills out 3rd and 4th fields of 4th data block for the number of terms present in the field. (Field code 5)

Solid Coeff of Thermal Exp

If input is supplied, will create a VISCEL EXP option; 2nd field of 3rd data block.

Liquid Coeff of Thermal Exp

3rd field of 3rd data block of VISCEL EXP option.

Reference Temperature

For all Shift Functions except None, 4th field of 3rd data block of SHIFT FUNCTION option.

Constant C1

For Shift Function 1 only - Field 1, 4th data block

Constant C2

For Shift Function 1 only - Field 2, 4th data block

92 Marc Preference Guide Material Library

Viscoelastic - Isotropic

Description

Constant Coefficients Co-Cm

For Shift Function 2 only - data block 4 - must be defined by a 1D material field where the independent value is arbitrary. The first value is Co and the number of field entries is placed in 3rd field of 3rd data block.

Activation Energ/ Gas Const.

For Shift Function 3 only - field 5, data block 3

Structural Relax. Ref. Temp.

For Shift Function 3 only - field 8, data block 3

Fraction Parameter

For Shift Function 3 only - field 6, data block 3

Abs Temperature Shift

For Shift Function 3 only - field 7, data block 3

Weighting Factors

For Shift Function 3 only - data blocks 4 & 5 where this is defined by a material time field. Weighing factor values are written to data block 4, and time values are written to datablock 5.

Note:

Main Index

Instantaneous values are entered for the elastic model, and the difference between the instantaneous value and the summation of the values in the series is the long-term property value.

Viscoelastic - Orthotropic

Description

Shift Function

Enters a 1, 2, 3, or -1 in the 2nd field of the 3rd data block of SHIFT FUNCTION to specify the type of function: WilliamsLandel-Ferry, Power Serires, Narayanaswamy, User Sub. TRSFAC. If the latter, no other data blocks are required. Input properties for the different shift functions are listed in the table above for Isotropic.

Youngs Modulus, E11/E22/E33

Defines the duration effects on the elastic moduli. This information is entered on the 2nd, 3rd, and 4th fields of the 4th datablock of the VISCELORTH option, and is optional. This is only valid when an Elastic and/or Plastic constitutive model is present.

Poissons Ratio 12/23/31

Defines the duration effects on the Poisson’s ratios. This information is entered on the 5th, 6th, and 7th fields of the 4th datablock of the VISCELORTH option, and is optional.

Shear Modulus G12/G23/G31

Defines the duration effects on the shear moduli. This information is entered on the fifth card of the VISCELORTH option, and is optional.

Solid Coeff of Thermal Exp

Same as for Isotropic

Liquid Coeff of Thermal Exp

Same as for Isotropic

Chapter 2: Building A Model 93 Material Library

Creep - Isotropic / Orthotropic / Anisotropic The following input is for the Creep constitutive model. This places a CREEP option in the input file. Creep

Description

Method

User Sub. CRPLAW - writes a zero in the 5th field of the 2nd data block of the CREEP option. No other data blocks beyond are written. User subroutine UCRPLW will automatically get called if it exists if Implicit creep is set. Power Law - Piecewise allows for input of the material properties in the table below.

Coefficient

Creates the CREEP option. It is compatible with all other constitutive models except Viscoelastic and Hyperelastic. This is 5th field in 2nd data block.

Exponent of Temperature

1st field of 3rd data block.

Temperature vs. Creep Strain

References a material field of temperature vs. value. Overrides Exponent of Temperature if present. Fills out 3rd data block.

Exponent of Stress

1st field of 4th data block.

Creep Strain vs. Stress

References a material field of stress vs. value. Overrides Exponent of Stress if present. Fills out 4th data block.

Exponent of Creep Strain

1st field of 5th data block.

Strain Rate vs. Creep Strain

References a material field of strain rate vs. value. Overrides Exponent of Creep Strain if present. Fills out 5th data block.

Exponent of Time

1st field of 6th data block.

Time vs. Creep Strain

References a material field of time vs. value. Overrides Exponent of Time if present. Fills out 6th data block.

Back Stress

For implicit creep - goes on 5th field of 4th data block of ISOTROPIC option and can vary with strain and/or temperature via a field definition in which case the WORK HARD and/or TEMPERATURE EFFECTS options may be written also.

Damping - Isotropic / Orthotropic / Anisotropic The following input is for Damping constitutive model. If any one of these values is present, they are placed on a DAMPING option and the element to which the material is associated are referenced. This option is used for harmonic analysis and direct transient dynamic integration only.

Main Index

94 Marc Preference Guide Material Library

Damping

Description

Raleigh Mass Matrix Multiplier

1st field of 4th data block of DAMPING option.

Raleigh Stiff Matrix Multiplier

2nd field of 4th data block of DAMPING option.

Numerical Damping Multiplier

3rd field of 4th data block of DAMPING option.

Thermal - Isotropic / Orthotropic / Anisotropic This input data creates the ISOTROPIC keyword option for heat transfer analysis. Thermal - Isotropic

Description

Method

User Subs. ANKOND ORIENT - writes a 1 to 2nd field of 3rd datablock of the ISOTROPIC option.

Conductivity

Defines the thermal conductivity. It is entered in the first data field on the fourth card of the ISOTROPIC option. This property is required. May vary with temperature via a defined material field and placed on 9b data block of the TEMPERATURE EFFECTS option.

Specific Heat

Defines the specific heat per unit mass which is an optional property. It is entered in the second data field on the fourth card of the ISOTROPIC option. May vary with temperature via a defined material field and placed on 10b data block of the TEMPERATURE EFFECTS option.

Density

Defines the mass density which is an optional property. It is entered in the third data field on the fourth card of the ISOTROPIC option.

Emissivity

Defines the emmisivity property (5th field of the 5a data block of the ISOTROPIC option). May vary with temperature via a defined material field and placed on 12b data block of the TEMPERATURE EFFECTS option.

Latent Heat vs Solidus Temp.

Both of these should be present or none. If one is missing the temperature values are treated as zero for the missing one. When both are present, they must reference Temperature material fields and they must all have exactly the same number of latent heats in them (with the same values). For Heat Transfer, the TEMPERATURE EFFECTS option is written with the values in the 5b data block. Field 3 of the 2b data block contains the number of latent heats in the fields.

Latent Heat vs Liquidus Temp.

This input data creates the ORTHOTROPIC keyword option for heat transfer analysis.

Main Index

Chapter 2: Building A Model 95 Material Library

Thermal - Orthotropic

Description

Method

User Subs. ANKOND ORIENT - writes a 1 to 2nd field of 3rd datablock of ORTHOTROPIC option.

Conductivity 11/22/33

Defines the thermal conductivity in the element’s coordinate system. These are entered in the 1st through 3rd data fields on the 4th datablock of the ORTHOTROPIC option, and are required properties.

Specific Heat

Defines the specific heat per unit mass which is an optional property. It is entered in the fifth data field on the fourth card of the ORTHOTROPIC option.

Density

Defines the mass density. It is entered in the fourth data field on the fourth card of the ORTHOTROPIC option. This property is optional.

Emissivity

Defines the emmisivity property (1st field of the 5th data block of the ORTHOTROPIC option). May vary with temperature via a defined material field and placed on 11b data block of the ORTHO TEMP option.

Latent Heat vs Solidus Temp.

Both of these should be present. If one is missing you must treat all the temperature values as zero for the missing one. When both are present, they must reference Temperature material fields and they must all have exactly the same number of latent heats in them (with the same values). For Heat Transfer, the TEMPERATURE EFFECTS option is written with the values in the 5b data block. Field 3 of the 2b data block contains the number of latent heats in the fields.

Latent Heat vs Liquidus Temp.

This input data creates the ANISOTROPIC keyword option for heat transfer analysis.

Main Index

96 Marc Preference Guide Material Library

Thermal - Anisotropic

Description

Method

User Subs. ANKOND ORIENT - writes a 1 to 2nd field of 3rd datablock of the ANISOTROPIC option - datablock 4a not written.

Conductivity 11/22/33

Defines the thermal conductivity in the element’s coordinate system. These are entered on the 4a datablock of the ANISOTROPIC option, and are required properties.

Specific Heat

Defines the specific heat per unit mass which is an optional property. It is entered in the 2nd data field on the 4th datablock of the ANISOTROPIC option.

Density

Defines the mass density which is an optional property. It is entered in the 1st data field on the 4th datablock of the ANISOTROPIC option.

Emissivity

Defines the emmisivity property (3rd field of the 4th data block of the ANISOTROPIC option). May vary with temperature via a defined material field and placed on 11b data block of the ORTHO TEMP option.

Latent Heat vs Solidus Temp.

Both of these should be present. If one is missing you must treat all the temperature values as zero for the missing one. When both are present, they must reference Temperature material fields and they must all have exactly the same number of latent heats in them (with the same values). For Heat Transfer, the TEMPERATURE EFFECTS option is written with the values in the 5b data block. Field 3 of the 2b data block contains the number of latent heats in the fields.

Latent Heat vs Liquidus Temp.

Plastic - Isotropic This input data can create the WORK HARD, TEMPERATURE EFFECTS, STRAIN RATE and the ISOTROPIC keyword options, with the 2nd data field of the 3rd data block of the latter set to VON MISES, LIN MOHRC, PBL MOHRC, BUY MOHRC, NORM ORNL, CRMO ORNL, REVP ORNL, ARST ORNL, GEN-PLAST, RIGID, or VISCO PLAS depending on the Yield Criteria set. One or more of the following input properties will appear depending on the options set:

Main Index

Chapter 2: Building A Model 97 Material Library

For Hardening Rules = Isotropic, Kinematic, and Combined, properties for each combination are: Von Mises Linear Mohr-Coulomb Parabolic Mohr-Coulomb Buyukozturk Concrete ORNL Models General Plasticity Stress vs. Plastic Strain or Yield Stress

Description Defines the uniaxial tensile stress versus plastic strain by reference to a tabular field. The field is selected from the Field Definition list. The field is created using the Fields application. See Fields - Tables. It is entered on the third card of the WORK HARD option. For Perfectly Plastic models, only a Yield Stress needs to be entered. See Caution on page 100 below. Extracts yield stress from first data point from field (zero plastic stain at the reference temperature) for the 5th field of 4th data block of ISOTROPIC option. Can also be temperature dependent which creates TEMPERATURE EFFECTS option. Can also be strain rate dependent if Strain Rate Method is Piecewise Linear. Accepts field of yield stress vs. strain rate and creates STRAIN RATE option with DATA in 2nd field. Data is input in data block 3 for Option B.

10th Cycle Yield Stress vs. Plastic Strain or 10th Cycle Yield Stress

Main Index

Accepts field of 10th cycle yield stress vs. plastic strain and creates WORK HARD option. Goes on same WORK HARD option as Stress vs. Plastic Strain. 7th field of 4th data block of ISOTROPIC option also extracted from first value of field. Can be temperature dependent also and reference temperature field which creates TEMPERATURE EFFECTS option (data block 7b). For Perfectly Plastic models, only a 10th Cycle Yield Stress needs to be entered.

or 10th Cycle Slope Data

Same as or Break Point Slope Data except for 10th Cycle Yield vs. Strain.

Coefficient C

Visible if Strain Rate Method is Cowper-Symonds. Creates STRAIN RATE option with COWPER in 2nd field. Data is placed in data block 3 for Option C.

Inverse Exponent P

Visible if Strain Rate Method is Cowper-Symonds. Creates STRAIN RATE option with COWPER in 2nd field. Data is placed in data block 3 for Option C.

98 Marc Preference Guide Material Library

Von Mises Linear Mohr-Coulomb Parabolic Mohr-Coulomb Buyukozturk Concrete ORNL Models General Plasticity

Description

Alpha

When set to Linear Mohr-Coulomb, defines the slope of the yield surface in square root J2 versus J1 space. It is entered in the sixth data field, on the fourth card of the ISOTROPIC option. This property is required.

Beta

When set to Parabolic Mohr-Coulomb, defines the beta parameter in the equation that defines the parabolic yield surface in square root J2 versus J1 space. It is entered in the sixth data field on the fourth card of the ISOTROPIC option. This property is required.

Note:

2 1/4 Cr-Mo ORNL, Reversed Plasticity ORNL, Full Alpha Reset ORNL are the same as Oak Ridge National Labs. Generalized Plasticity is the same as Von Mises.

Hill Yield Barlat

Description

Stress vs. Plastic Strain

Same as table above.

or Yield Stress Kinematic Ratio

This is only writen if the Hardening Rule is set to Combined and is written to the 6th field of the 4th data block for ISOTROPIC, the 2nd field of the 6th data block for ORTHOTROPIC, and 3rd field of the 4th data block for ANISOTROPIC.

Stress 11, 22, 33 Yield Ratio Stress 12, 23, 13 Yield Ratio

These are property words for Hill Yield criterion and are writen to fields 1-6 of the 5th datablock for ISOTROPIC, fields 3-8 of the 6th data block for ORTHOTROPIC, and fields 1-6 or the 4e data block for ANISOTROPIC.

M, C1, C2, C3, C6

These are property words for Barlat criterion and are writen to fields 1-5 of the 5th datablock for ISOTROPIC, fields 3-7 of the 6th data block for ORTHOTROPIC, and and fields 1-5 or the 4e data block for ANISOTROPIC.

For the rest of the Hardening Rules, the input properties are as shown. No WORK HARD or STRAIN RATE options are created with these.

Main Index

Chapter 2: Building A Model 99 Material Library

Power Law &

Description

Rate Power Law Coefficient A

1st field of 6th data block of ISOTROPIC option.

Coefficient B

3rd field of 6th data block of ISOTROPIC option.

Exponent M

2nd field of 6th data block of ISOTROPIC option.

Exponent N

4th field of 6th data block of ISOTROPIC option.

Initial Equivalent Strain

5th field of 6th data block of ISOTROPIC option (Power Law). Not used in pre Marc 2005.

Minimum Yield Stress

5th field of 6th data block of ISOTROPIC option (Rate Power Law). Not used in pre Marc 2005. All the above properties can be temperature dependent if Use Tables is ON and Marc 2005 or later.

Main Index

Johnson-Cook

Description

Coefficient A

1st field of 8th data block of ISOTROPIC option.

Coefficient B

2nd field of 8th data block of ISOTROPIC option.

Coefficient C

4th field of 8th data block of ISOTROPIC option.

Exponent M

5th field of 8th data block of ISOTROPIC option.

Exponent N

3rd field of 8th data block of ISOTROPIC option.

Initial Strain Rate

8th field of 8th data block of ISOTROPIC option.

Room Temperature

6th field of 8th data block of ISOTROPIC option.

Melt Temperature

7th field of 8th data block of ISOTROPIC option.

Kumar

Description

Coefficient B0

1st field of the 7a data block of ISOTROPIC option.

Coefficient A

2nd field of the 7a data block of ISOTROPIC option. Not necessary if B1-B3 is supplied.

Coefficient B1 - B3

3rd - 5th fields of the 7a data block of ISOTROPIC option. Not necessary if A is supplied.

Coefficient N

1st field of the 7b data block of ISOTROPIC option. Not necessary if B4-B6 is supplied.

Coefficient B4 - B5

2nd - 4th fields of the 7b data block of ISOTROPIC option. Not necessary if N is supplied.

100 Marc Preference Guide Material Library

Note:

Perfectly Plastic is identical to Elastic-Plastic except that no hardening rules apply. Thus no WORK HARD options are created; only ISOTROPIC and STRAIN RATE options with TEMPERATURE EFFECTS, if requested. Stress vs Plastic Strain is replaced with Yield Stress data only as is 10th Cycle Yield vs. Strain replaced with 10th Cycle Yield Stress data. Thus no tabular data is necessary.

Note:

Rigid-Plastic is identical to Elastic Plastic for Hardening Rules: Power Law, Rate Power Law, Johnson-Cook, and Kumar. Piecewise Linear is identical to Von Mises. The difference here is that the ISOTROPIC option is written and does not contain E or nu. If an Elastic constitutive model has been created it is ignored, or that is, those values are ignored (elasticity is ignored). A RIGID identifier is placed in the ISOTROPIC option.

Caution:

In general, you should use true stress vs natural log of plastic strain when defining plasticity curves. The first value of plastic strain in a stress-strain field must be zero. The corresponding yield stress for this zero plastic strain is placed in the ISOTROPIC option as the Tensile Yield Stress. If yield stress can vary with temperature, the first data point in the field must be the temperature at this yield stress, which will be placed in the TEMPERATURE EFFECTS option, unless you are using the TABLE format, in which the fully defined fields will be converted to equivalent TABLES. The stress-strain field causes the WORK HARD, DATA option to be written if the first pair of data points of the given field is: (zero, nonzero) This indicates that true stress vs natural log plastic strain data has been supplied. This is consistent with default functionality of Marc. However, if the first data point pair is detected to be (nonzero, nonzero), then this indicates that the engineering stress/strain curve has been given, where the strain is the total strain. Thus the data is converted from engineering stress/strain to true stress/strain before writing the data to the input file. In any case, stress/strain data must begin at the yield stress. In other words, the first pair of data points cannot both be zero. If conversion is necessary, the following formulation is used: s = Engineering Stress, e = Engineering Strain, s = True Stress, et = True Total Strain, ee = True Elastic Strain, ep = True Plastic Strain, E = Young’s Modulus σ Z s(1 H e) ε p Z ε t Ó ε e Z ln ( 1 H e ) Ó σ --E

Main Index

Chapter 2: Building A Model 101 Material Library

Plastic - Orthotropic / Anisotropic This input data can create the ORTHOTROPIC, or ANISOTROPIC, plus WORK HARD, ORTHO TEMP, and STRAIN RATE options. The second data field on the third card of the ORTHOTROPIC or ANISOTROPIC options is set to the corresponding yield criteria. Note:

All of the Yield Criteria / Hardening Rules have identical inputs as for Isotropic - Plastic materials. The input property values are placed in the equivalent location on the ORTHOTROPIC or ANISOTROPIC options. The only difference is noted here for von Mises yield criteria.

Plastic - von Mises

Description

Stress vs. Plastic Strain or Tensile Yield Stress

Same as description for Isotropic Elastic-Plastic - creates WORK HARD, ORTHO TEMP and STRAIN RATE options. Yield Stress is extracted from 1st data point - 1st field of 6th data block of ORTHOTROPIC option or 2nd field on the 4th data block of the ANISOTROPIC option. Temperature field reference creates ORTHO TEMP option. If Strain Rate Method is Piecewise Linear, accepts field of yield stress vs. strain rate and creates STRAIN RATE option with DATA in 2nd field. Data is input in data block 3 for Option B. Or defines an isotropic yield stress. It is entered in the first data field on the sixth card of the ORTHOTROPIC option and is a required property when the plasticity type is Perfectly Plastic.

Note:

Main Index

Perfectly Plastic is identical to Elastic-Plastic except that no hardening rules apply. Thus no WORK HARD options are created. Stress vs Plastic Strain is replaced with Yield Stress data only as is 10th Cycle Yield vs. Strain replaced with 10th Cycle Yield Stress data. Thus no tabular data is necessary.

102 Marc Preference Guide Material Library

Shape Memory - Isotropic This input data creates the SHAPE MEMORY keyword option. Shape Memory

Description

Memory Model

Either a Mechanical (Auricchio’s) model or a ThermalMechanical model is written. These are options to the constitutive model. Datablock 3, field 2. Note: Reference temperature values taken from the Elastic constitutive model.

Property Word

Description (Mechanical - Auricchio’s)

Young’s Modulus & Poisson’s Ratio

These must be defined in an Elastic constitutive model. Thus an Elastic constitutive model must exist in order to write a SHAPE MEMORY option for the Mechanical option. Block 4b, 1st and 2nd fields, respectively.

Sigma AS_s

Block 4b, field 3.

Sigma AS_f

Block 4b, field 4.

Sigma SA_s

Block 4b, field 5.

Sigma SA_f

Block 4b, field 6.

Epsilon L (0.0 ~ 1.0)

Block 5b, field 1.

Alpha (0.0 ~ 0.10)

Block 5b, field 2.

Martensite Slope

Block 5b, field 4.

Austenite Slope

Block 5b, field 5.

Property Word

Description (Thermal-Mechanical)

Young’s Modulus

Block 4a, fields 1-5, respectively

Poisson’s Ratio Coefficient of Thermal Expansion Initial Yield Stress Mass Density (Austenite) Young’s Modulus

Block 5a, fields 1-5, respectively

Poisson’s Ratio Coefficient of Thermal Expansion Initial Yield Stress Mass Density (Martensite) Martensite Start Temperature

Main Index

Block 6a, field 1.

Chapter 2: Building A Model 103 Material Library

Shape Memory

Description

Martensite Finish Temperature

Block 6a, field 2.

Martensite Slope

Block 6a, field 3.

Austenite Start Temperature

Block 6a, field 4.

Austenite Finish Temperature

Block 6a, field 5.

Austenite Slope

Block 6a, field 6.

Deviatoric Trans. Strain

Block 7a, field 1.

Volumetric Trans. Strain

Block 7a, field 2.

Twinning Stress

Block 7a, field 3.

Stress Dependency Coefficient g-A

Block 8a, field 1.

Exponent g-B

Block 8a, field 2.

Coefficient g-C

Block 8a, field 3.

Exponent g-D

Block 8a, field 4.

Coefficient g-E

Block 8a, field 5.

Exponent g-F

Block 8a, field 6.

Nondimensionalizign Stress g-O

Block 9a, field 1.

Cut Off Value g-max

Block 9a, field 2.

Stress at g-max

Block 9a, field 3.

Damage - Isotropic / Orthotropic / Anisotropic Below is the Damage constitutive model and writes the DAMAGE option. This is a constitutive model valid for the types listed above and can reference ISOTROPIC, ORTHOTROPIC, ANISOTROPIC options or one of the Hyperelastic options: MOONEY, OGDEN, GENT, ARRUDA-BOYCE, but not both. So if a Hyperelastic model is active, and the Damage model below is 4,5, or 6, it should reference the Hyperelastic model; if it is 0-3, 9 or 10 it should reference the Isotropic, Orthotropic, or Anisotropic materials.

Main Index

104 Marc Preference Guide Material Library

Damage

Description

Damage Type

For Isotropic, all models are valid. For Orthotropic and Anisotropic only models 0-3 and 9/10 are valid. The given model number is written to the 2nd datablock of the DAMAGE option (the valid property words are indicated):

Damage Model

0 - No Nucleation (1-5) 1 - Strain Controlled Nucleation (1-6,8,9) 2 - Stress Controlled Nucleation (1-5, 7-9) 3 - User Sub UVOIDN (1-5) 4 - Rubber - additive decomposition (10-17, 24) 5 - Rubber - multiplicative decomp. (18-24) 6 - User Sub UELDAM (none) 9 - Simplified Yield - User Sub UDAMAG (none) 10 - Simplified Yield/E - User Sub UDAMAG (none)

Main Index

1st Yield Surface Multiplier

(1) 1st field, 4a data block of DAMAGE option.

2nd Yield Surface Multiplier

(2) 2nd field, 4a data block

Initial Void Volume Fraction

(3 3rd field, 4a data block)

Critical Void Volume Fraction

(4) 4th field, 4a data block

Failure Void Volume Fraction

(5) 5th field, 4a data block

Mean Strain for Nucleation

(6) 7th field, 4a data block

Mean Stress for Nucleation

(7) 7th field, 4a data block

Standard Deviation

(8) 8th field, 4a data block

Volume Fraction of Void Nucleation

(9) 9th field, 4a data block

1st Scale Factor - Cont. Damage

(10) 1st field, 4b data block

1st Relax Factor - Cont. Damage

(11) 2nd field, 4b data block

2nd Scale Factor - Cont. Damage

(12) 3rd field, 4b data block

2nd Relax Factor - Cont. Damage

(13) 4th field, 4b data block

1st Scale Factor - Discont. Damage

(14) 5th field, 4b data block

1st Relax Factor - Discont. Damage

(15) 6th field, 4b data block

Chapter 2: Building A Model 105 Material Library

Damage

Description

2nd Scale Factor - Discont. Damage

(16) 7th field, 4a data block

2nd Relax Factor - Discont. Damage

(17) 8th field, 4a data block

1st Scale Factor

(18) 1st field, 4c data block

1st Proportional Term

(19) 2nd field, 4c data block

1st Relax Rate Constant

(20) 3rd field, 4c data block

2nd Scale Factor

(21) 4thfield, 4c data block

2nd Proportinal Term

(22) 5th field, 4c data block

2nd Relax Rate Constant

(23) 6th field, 4c data block

Scale Factor @ Infinity

(24) 3rd field, 3rd data block

Cracking - Isotropic Below is the Cracking constitutive model for concrete cracking and writes the CRACK DATA option. Cracking

Description

Method

Either Entered Values or User Sub. UCRACK... If user subroutine is specified, CRACK DATA may not have to be written - needs investigation.

Critical Stress

1st field, 3rd data block of CRACK DATA

Softening Modulus

2nd field, 3rd data block

Crushing Strain

3rd field, 3rd data block

Shear Retention

4th field, 3rd data block

Forming Limit - Isotropic / Orthotropic / Anisotropic Below is the Forming Limit constitutive model addition for Isotropic, Orthotropic, and Anisotropic material categories. This writes the FORMING LIMIT option.

Main Index

106 Marc Preference Guide Material Library

Forming Limit

Description

Method

Either Fitted, Predicted, or Table. A zero, 1, or 2 is written to the 1st field of the 2nd data block, respectively.

C0-C1 and D1-D4

Data block 3a and 4a for Option 0 (Method - Fitted)

Strain Hardening Exponent

Data block 3b for Option 1 (Method - Predicted)

Thickness Coefficient Forming Limit Diagram

Data block 3c of Option 2 (Method - Table). Reference value always 1.0. Must use a TABLE option for this as it must reference a Strain field.

Grain Size - Isotropic Below is the Grain Size constitutive model for Isotropic model only. This writes the GRAIN SIZE and MATERIAL DATA options. Grain Size

Description

Method

Either Yada or User Sub UGRAIN. A 1 or -1, respectively, in 2nd field of 3rd data block of GRAIN SIZE option.

Initial Grain Size

Data block 4, 1st field

C1-C5

Data block 4, fields 2-6.

Activation Energy (Q)

This is written to the MATERIAL DATA option (1st field, 4th data block) where the GRAIN SIZE material ID is referenced in the MATERIAL DATA option.

Soil - Isotropic Below is the Soil constitutive model addition for Isotropic and Orthotropic models only. This writes the SOIL option and if necessary, the INITIAL POROSITY, INITIAL VOID RATIO, INITIAL PC and SPECIFIC WEIGHT options.

Main Index

Soil

Description

Model

Either Linear, Cam Clay, or User Sub. HYPELA. This is indicated in the 2nd field of the 3rd data block by entering LINEAR, NON LINEAR (user sub. HYPELA) or CAMCLAY. If a Plastic model is also defined, this overrides this option and the Plastic model setting will write either VON MISES, LIN MOHRC, or PLB MOHRC for von Mises, Linear Mohr-Coulomb or Parabolic Mohr-Coulomb yield models. For orthotropic models, the ORTHOTROPIC keyword is written.

Dynamic Viscosity

Data block 4, 8th field

Chapter 2: Building A Model 107 Material Library

Soil

Description

Fluid Density

Data block 4, 7th field

Fluid Bulk Modulus

Data block 4, 7th field

Permeability

Data block 5, 1st field

Compression Ratio

Data block 5, 2nd field

Recompression Ratio

Data block 5, 3rd field

Critical State Curve Slope

Data block 5, 4th field

Young’s Modulus Poisson’s Ratio Mass Density Coefficient of Thermal Expansion

These values get placed in the 1st-4th fields of datablock 4. If any of these values reference a temperature field, the TEMPERATURE EFFECTS is written (or TABLES if Use Tables is ON). Or for Orthotropic properties, they are placed in the 4th, 5th, and 6th datablocks.

Yield Stress

This value comed from a Plastic constitutive model. If this model is not available, then zero is written for the Yield Stress. If a Perfectly Plastic model is available, the Yield Stress is placed in the 5th field of the 4th datablock. If a stress-strain field is available, then the WORK HARD option is written (or TABLE) with this value being the reference value at zero plastic strain.

Initial Porosity Initial Void Ratio

These properties are written to the INITIAL POROSITY, INITIAL VOID RATIO, INITIAL PC, and SPECIFIC WEIGHT options, respectively and are assigned to the same elements as this material.

Initial Preconsolidation Pressure Gravity Constants in 1st-3rd coordinate directions Powder - Isotropic

Below is the Powder constitutive model for Isotropic model only. This writes the POWDER, RELATIVE DENSITY, and DENSITY EFFECTS options. Powder

Main Index

Description

Method

Either Entered Values or User Sub. UPOWDR. If the latter is seletect, then no POWDER option (or RELATIVE DENSITY, DENSITY EFFECTS) options are written. Everything is taken care of in the UPOWDR routine supposedly.

Material Prop. Gama

Data block 4, 6th field

Material Prop. Beta

Data block 4, 7th field

Powder Viscosity

Data block 4, 8th field

Gamma Coef. 1-4

Data block 6

108 Marc Preference Guide Material Library

Powder

Description

Beta Coef. 1-4

Data block 7

Initial Relative Density

This goes on the RELATIVE DENSITY option. Note that for shell elements, the integration points have to be written also.

Young’s Modulus Poisson’s Ratio Mass Density Coefficient of Thermal Expansion

These come from an Elastic constitutive model, which must be defined also in addition to the Powder model. These values get placed in the 1st-4th fields of datablock 4. If any of these values reference a temperature field, the TEMPERATURE EFFECTS is written (or TABLES if Use Tables is ON). If the first two (or last two for Coupled analysis) reference a Strain field, then the DENSITY EFFECTS, DATA option is written with the density effects field written to the appropriate block of the option. This is written in an identical way to the TEMPERATURE EFFECTS, DATA option. We are using the Strain field to indicate a Density field in this case since Density fields are not yet supported in Patran Fields application. Of course if Use Tables is ON, then TABLES are used and not TEMP/DENSITY EFFECTS.

Yield Stress

This value comed from a Plastic constitutive model. If this model is not available, then zero is written for the Yield Stress. If a Perfectly Plastic model is available, the Yield Stress is placed in the 5th field of the 4th datablock. If a stress-strain field is available, then the WORK HARD option is written (or TABLE) with this value being the reference value at zero plastic strain.

Electrostatic - Isotropic/Orthotropic Below is the Electrostatic constitutive model for Isotropic and Orthotropic models only. This writes the ISOTROPIC, ELECTROSTA or ORTHOTROPIC, ELECTROSTA options, respectively. Powder

Description

Permittivity, Permittivity 11/22/33

Values written to the above mention options.

Electrodynamic - Isotropic/Orthotropic/Anisotropic Below is the Electrodynamic constitutive model for Isotropic, Orthotropic, and Anisotropic models. This writes the ISOTROPIC, THERMAL or ORTHOTROPIC, THERMAL options, respectively.

Main Index

Chapter 2: Building A Model 109 Material Library

Powder

Description

Resistivity, Resistivity 11/12/13/22/23/33

Values written to the above mention options.

Magnetostatic - Isotropic/Orthotropic Below is the Magnetostic constitutive model for Isotropic and Orthotropic models. This writes the ISOTROPIC or ORTHOTROPIC options, respectively for magnetostatics. Powder

Description

Permeability, Permeability 11/22/33 Inverse Permeability, Inverse Permeability 11/22/33

Values written to the above mention options.

Hn-Bn / Bn-Hn Curve

These curves are defined under the Field application using a Magnetic material field.

Piezoelectric - Isotropic/Orthotropic/Anisotropic Below is the Piezoelectric constitutive model for Isotropic, Orthotropic, and Anisotropic models. This writes the ISOTROPIC or ORTHOTROPIC or ANISOTROPIC options, respectively for piezoelectic

Main Index

Powder

Description

Piezoelectric Constants Electric Permitivity 11/22/33

Values written to the above mention options.

110 Marc Preference Guide Material Library

Composite - Homogeneous The following composite material types may also be defined as shown in this table.

The Composite forms are used to create new materials by combining existing materials. All of the composite materials, with the exception of the laminated composites, can be assigned to elements, as any homogeneous material, through the element property forms. For the laminated composites, the section thickness is entered indirectly through the definition of the stack, and the Homogeneous option, on the Element Properties for shells, plates and beam, must be changed to Laminate to avoid reentry of this information. For details on entering data on the Composite forms, refer to the Composite Materials Construction (p. 116) in the Patran Reference Manual. For all composite types except Composite - Laminate, an equivalent set of properties are entered in the ANISOTROPIC keyword option when an Marc input file is created. For Composite - Laminate the COMPOSITE option is used. Caution: It is extremely important that when you define a layup (in the form on the next page), that it be done from top to bottom. Think of the top layer of the layup as being the top row of the spreadsheet and you should have no problems. As an example of how important this is, consider a cantilevered flat plate subject to an axial load with two layers. The top layer is extremely flexible compared to the bottom layer, which is relatively much stiffer than the top. Due to the shear forces created between the layers, the vertical deflection should tend to favor the side of the stiffer layer, thus the plate should bend down. If the layer is defined from bottom to top instead of top to bottom, you will get what appears to be the opposite answer where the deflection bends up. The answers are correct in both cases. The problem is how you defined the layup.

Main Index

Chapter 2: Building A Model 111 Material Library

Composite - Laminate This form appears when Composite is the selected Object and Laminate is the selected Method in the Materials application. Use this form to create the COMPOSITE keyword option.

Caution: See the caution on the previous page. Layers must be defined from top to bottom.

Constitutive Model Status A single material may contain multiple constitutive models. The constitutive model used is determined by the Constitutive Model Status. Patran will use all constitutive models active when the analysis is submitted. Redundant or unneeded constitutive models should be rendered inactive.

Main Index

112 Marc Preference Guide Material Library

Note:

The modifications are not saved until Apply button is pressed.

Experimental Data Fitting This is a very useful tool available under the Tools pull-down menu from the main Patran form and is only available if the Analysis Preference is set to Marc.

The tool is used to curve fit experimentally derived raw elastomeric material data and fit a number of material models to the data. This data can then be saved as constitutive hyperelastic and/or viscoelastic models for use in an Marc analysis. The operation of curve fitting is done in three basic steps corresponding to the actions in the Action pull-down menu. 1. Import Raw Data - data is read from standard ASCII files and stored in Patran in the form of a field (table).

Main Index

Chapter 2: Building A Model 113 Material Library

2. Select Test Data - the fields from the raw data are associated to a test type. 3. Calculate Properties - the curve fit is done to the selected test data; coefficients are calculated based on the selected material model; curve fit is graphically displayed and the properties can be saved as a constitutive model for a later analysis. Note:

Strain input should be engineering strain to give reasonable results.

The Ogden Formulation was first given in the paper "Large Deformation Isotropic Elasticity - on the Correlation of Theory and Experiment for Incompressible Rubberlike Solids", R.W. Ogden, Proc.R.Soc.Lond.A., Vol. 326, 526-584 (1972). The curve fitting determines ( mu_n, alpha_n ) pairs. These constants are material constants and may not represent physical values for rubbers since during the curve fitting process, certain calculations are made with the assumption of imcompressibility. The most important issue during data fitting is to make sure that the data fit is sufficiently close. The Foam Model (see - Storåkers, B., On Material Representation and Constitutive Branching in Finite Compressible Elasticity, Journal of the Mechanics and Physics of Solids, vol.34, no.2, pp. 125-145, 1986.) is a compressible Ogden formulation and should be used for materials going through large volumetric deformations. The curve fitting calculates sets of ( mu_n, alpha_n, beta_n ) coefficients where the Beta coefficients represent to some extent a measure of foam compressibility. The Planar (Pure) Shear and Simple Shear responses are identical to the Ogden Formulation since the motion is isochoric; therefore, use of either Pure or Simple shear experiments to determine the Beta coefficients is pointless. The model works well in compression (densification). When using the foam model, note that like the Ogden formulation, it is acceptable to get different parameters for the fit as long as the fit is correct and the also yields a positive definite strain energy function for the range of the fit. (A positive definite strain energy function means that the material matrix derived from it will not have a negative Jacobian through the range of deformation). If a negative Jacobian occurs during the analyis, this may cause an exit 1005 or 1009 which signifies "inside-out elements". The beta coefficients (which represent some measure of compressibility) may vary since there are more than one way to handle the strain energy attributed to the volumetric deformation. For the foam model, compressibility (in the form of fictive poisson's ratio) is included and in the test data, the independent stretch and volume ratios would need to be considered. Finally, it is highly recommended that mathematical checks be used for all data fitting, especially for the Ogden and Foam formulations.

Main Index

114 Marc Preference Guide Material Library

Import Raw Data You can import the raw materials data by following these general steps:

Keep in mind the following points and considerations when importing raw data: 1. You can skip any number of header lines in the raw data file by setting the Header Lines to Skip data box. 2. You may edit the raw data file after selecting it by using the Edit File... button. The editor is Notepad on Windows platforms and vi on UNIX platforms unless you change the environment variable P3_EDITOR to reference a different editor. The editor must be in the user’s path or the entire pathname must be referenced. 3. Raw data files may have up to three columns of data. By default the first column of data is the independent variable value. The second column is the measured data, and the last column can be the area reduction or volumetric data. More than three columns is not accepted. If the third column is blank, the material is considered incompressible.

Main Index

Chapter 2: Building A Model 115 Material Library

4. If you have cross-sectional area reduction data in the third column, you can give it an optional field name also by turning ON the Area Data toggle and supplying an Area Field Name. If you have three columns of data and this toggle is OFF, the third column is still detected and read and two fields are created. This results in a _C1 and _C2 being appended to the New Field name. 5. The data may be space, tab, or comma delimited. 6. If for some reason the independent and dependent columns need to be interchanged, you can turn the Switch Ind./Dep. Columns toggle ON. Check your imported fields before proceeding to ensure they are correct. This is done in the Fields application. 7. When you press the Apply button, you will be taken to the second step. If you need to import more than one file, you will have to reset the Action pull-down.

Main Index

116 Marc Preference Guide Material Library

Select Test Data Once raw test data is imported, you must associate them with particular test types or modes by following these steps:

Keep in mind the following points and considerations when selecting test data: 1. Typical stress-strain data for Deformation Mode tests are referenced in the Primary column. If you have volumetric data, these are entered in the Secondary column databoxes and are optional. 2. For Viscoelastic (time relaxation data), you must turn ON the ViscoElastic toggle. Only viscoelastic curve fitting will be done in this case. To return to Deformation Mode, turn this toggle OFF. 3. Damage models are not yet supported. 4. When you press the Apply button, you will be taken to the third step.

Main Index

Chapter 2: Building A Model 117 Material Library

Calculate Properties Once test data has been associated to a test type or mode the curve fit function is performed by following these steps:

Keep in mind the following points and considerations when calculating properties: 1. The plots are appended to the existing XY Window until you press the Unpost Plot button. You can turn the Append function ON/OFF under the Plot Parameters... form.

Main Index

118 Marc Preference Guide Material Library

2. By default, all the deformation modes are plotted along with the raw data even if raw data has not been supplied for those modes. This is very important. These additional modes are predicted for you. You should always know your model’s response to each mode of deformation due to the different types of stress states. For example, a rule of thumb for natural rubber and some other elastomers is that the tensile tension biaxial response should be about 1.5 to 2.5 times the uniaxial tension response. 3. You can turn ON/OFF these additional modes or any of the curves under the Plot Parameters button as well as change the appearance of plot. More control and formatting of the plot can be done under the XY Plot application on the Patran application switch on the main form. 4. Viscoelastic constitutive models are useless without a Hyperelastic constitutive model also. Be sure your model has both defined under the same material name if you use viscoelastic properties. 5. You may actually change the coefficient values in the Coefficients spread sheet if you wish to see the effect they have on the curve fit. Select one of the cells with the coefficient you wish to change, then type in a new coefficient value in the Coefficient Value data box and press the Return or Enter key. Then press the Plot button again. If you press the Apply button, the new values will be saved in the supplied material name. 6. For viscoelastic relaxation data, the Number of Terms used in the data fit should, as a rule of thumb, be as many as there are decades of data. 7. A number of Optional and Plot Parameters are available to message the data and control the curve fitting. See the table below for more detailed descriptions.

Main Index

Chapter 2: Building A Model 119 Material Library

Optional Parameters

Description

Uniaxial Test Biaxial Test

Only available for Ogden and Foam models. Defines whether area or volumetric data was measured.

Planar Shear Test

Main Index

Mathematical Checks

OFF by default. Only available for Ogden and Foam models.

Positive Coefficients

OFF by default. Will force positive coefficients to be determined if ON. Available for all Model types.

Extrapolate Left/Right Bounds

OFF by default. If ON, the Left and Right Bounds databoxes will become available to enter data to extrapolate results to. Available for all Model types.

Error

Can be set to Relative (default) or Absolute. Good for all Model types.

Error Limit

Only available for Ogden, Foam, Arruda-Boyce, and Gent Models.

# of Iterations

Only available for Ogden, Foam, Arruda-Boyce, and Gent Models.

Convergence Tolerance

Only available for Ogden, Foam, Arruda-Boyce, and Gent Models. This can have a significant difference in the calculated coefficients and the plots.

Use Fictive Coefficient Fictive Coeff.

Only valid for Foam. Allows you to enter a fictive Poison’s ratio for use in the data fit.

Append Curves

Curves will be appended to existing plot. If OFF, plot will be cleared each time.

X/Y Axis Options

Plot data in linear or logarithmic fashion.

Modes

Turns ON/OFF each respective mode including the raw data plot.

120 Marc Preference Guide Element Properties

Element Properties The Element Properties application allows properties to be defined and assigned or associated to various groups of elements supported by the Marc Preference.

Main Index

Chapter 2: Building A Model 121 Element Properties

For more details on the Element Properties application, see Create Element Property Sets (p. 68) in the Patran Reference Manual.

The following table outlines the supported element types. For a list by Marc element number, see the next table.

Main Index

122 Marc Preference Guide Element Properties

Dimension • 0D

(structural) (coupled) • 0D

Type

Option 1

Option 2

• Mass • Spring/Damper • Spring/Damper

(thermal) • 1D

(structural) (coupled)

• General

• Straight

Beam

• Standard (Type varies) • General (Type varies)

• Curved (Type varies) • Elastic

Beam

• General

Section

• Euler-Bernoulli (Type 52) • Euler-Bernoulli w/Shear (Type 98) • Straight Beam(Type 31)

• Arbitrary

Section

• Standard Formulation (Type 31) • Euler-Bernoulli w/Shear (Type 98)

• Curved w/Arbitrary Section (Type 31) • Curved w/General Section (Type 31) • Curved w/Pipe Section (Type 31) • Pipe Section (Type 31) • Thin-

Walled Beam

• Closed

Section

• Standard Formulation (Type 14) • Linear Axial Strain (Type 25) • Shell Stiffener (Types 76, 78)

• Open Section

• Standard Formulation (Type 13) • Shell Stiffener (Types 77, 79)

• Pipe Section

• Standard Formulation (Type 14) • Linear Axial Strain (Type 25) • Shell Stiffener (Types 76, 78)

• Planar

Beam

• Homogeneous • Standard Formulation (Types 5, 45)

or Laminate

• Parabolic Shear Strain (Type 45) • Curved Isoparametric (Type 16)

• Spring/Damp • Nonlinear (Type SPRING)

er • Axisym

Shell

• Linear (Type SPRING) • Homogeneous • Standard Formulation (Types 1, 89)

or Laminate

• Fourier (Types 90) • Isoparametric (Types 15)

Main Index

Chapter 2: Building A Model 123 Element Properties

Dimension • 1D (cont.)

Type • Gap

(structural) (coupled)

Option 1

Option 2

• Fixed Direction (Type 12) • True Distance (Type 12) • Friction with Bending (Type 97)

• Cable

• Initial Stress Input (Type 51) • Length Input (Type 51)

• Truss (Types 9, 64) • Spring (Type SPRING) • Damper (Type SPRING) • Rebar

• Plane Strain (Types 165, 168) • Axisymmetric (Types 166, 169) • Axisymmetric w/Twist (Types 167, 170)

• 1D (thermal/

coupled)

• Axisym

Shell • Link

• Homogeneous • Linear Temp Distr (Types 87, 88)

or Laminate

• Quadratic Temp Distr (Types 87, 88)

• Magnetostatic (Type 183) • Conduction (Types 36, 65) • Convection/Radiation (Types 36, 65)

• Spring/Damper (Type SPRING) • 2D

(structural) (coupled)

• Thin Shell

• Homogeneous or Laminate (Types 49, 72, 138, 139)

• Thick Shell • Homogeneous • Standard Formulation (Types 22, 75)

or Laminate • Membrane

• Homogeneous (Types 18, 30)

• Shear

• Homogeneous (Type 68)

Panel • 2D Rebar (Types 147, 148)

Main Index

• Reduced Integration (Type 140)

124 Marc Preference Guide Element Properties

Dimension • 2D (cont.)

Type • 2D Solid

Option 1

Option 2

• Axisymmetric

• Standard Formulation(Types 2, 10, 28, 126)

(structural) (coupled)

• Hybrid(Herrmann)

(Types 82,156,33,129) • Hybrid(Herrmann) / Reduced Integration

(Types 59, 119, 156) • Hybrid(Herrmann) / Twist

(Types 66, 83) • Reduced Integration (Types 55, 116) • Twist (Type 20, 67) • Laminated Composite

(Types 152 / GASKET, 154) • Fourier (Type 62) • Hybrid(Herrmann) / Fourier (Type 63) • Reduced Integration / Fourier (Type 73) • Hybrid(Herrmann) / Reduced Integration /

Fourier (Type 74) • Bending (Types 95, 96) • Semi-Infinite (Types 92, 94) • Electromagnetic (Type 112) • Piezoelectric (Type 162) •

Main Index

•

• Plane Stress

• Piezoelectric (Type 160)

Chapter 2: Building A Model 125 Element Properties

Dimension •

Type •

Option 1 • Plane Strain

Option 2 • Standard Formulation

(Types 6, 11, 27, 125) • Hybrid(Herrmann)(Types 32, 80, 128, 155) • Hybrid(Herrmann) / Reduced Integration

(Types 58, 118, 155) • Reduced Integration (Types 54, 115) • Generalized (Types 19, 29) • Generalized / Reduced Integration (Type 56) • Generalized / Hybrid(Herrmann)

(Types 34, 81) • Generalized / Hybrid(Herrmann) / Reduced

Integration (Type 60) • Laminated Composite

(Type 151 / GASKET, 153) • Semi-Infinite (Type 91 93) • Electromagnetic (Type 111) • Piezoelectric (Type 161) •

•

• Plane Stress

• Standard Formulation(Types 3, 26, 124) • Reduced Integration (Types 53, 114)

• 2D

• Shell

(thermal • 2D Solid

• Homogeneous • Linear Temp Distr (Types 50 85, 86)

or Laminate

• Quadratic Temp Distr (Types 50, 85, 86)

• Axisymmetric

• Standard Formulation (Types 38, 40, 42,

132) • Reduced Integration (Types 70, 122) • Laminated Composite (Types 178, 180) • Semi-Infinite (Types 102, 104) • Planar

• Standard Formulation (Types 37, 39, 41,

131) • Reduced Integration (Types 69, 121) • Laminated Composite (Types 177, 179) • Semi-Infinite (Types 101, 103)

Main Index

126 Marc Preference Guide Element Properties

Dimension • 3D

Type • Solid

(structural) (coupled)

Option 1 • Standard

Geometry

Option 2 • Standard Formulation (Types 7, 21, 127,

134) • Hybrid(Herrmann) (Types 35, 84, 130, 157) • Hybrid(Herrmann) / Reduced Integration

(Types 61, 120, 130, 157) • Reduced Integration (Types 57, 117, 127,

134) • Electromagnetic (Type 113) • Piezoelectric (Types 163 164) • Magnetstatic (Types 109 181 182) • Auto Shell

Typing

• Standard Formulation (Types 7, 21) • Reduced Integration (Type 57)

• Laminated Composite (Types 149 / GASKET, 150) • Semi-Infinite (Types 107, 108) • 3D

• Solid

(thermal)

• Standard Formulation (Types 43, 44, 133, 135) • Reduced Integration (Types 71, 123, 135) • Semi-Infinite (Types 105, 106) • Semi-Infiite - Magnetostatic (Type 110)

• Laminated Composite (Types 175, 176)

Marc supported element types: Element #

Main Index

Description

Dimension

Topologies

• Element 1

Straight Axisymmetric Shell

1D

Bar/2

• Element 2

Axisymmetric Triangular Ring

2D

Tri/3

• Element 3

Plane Stress Quadrilateral

2D

Tri3/, Quad/4

• Element 4

Curved Quadrilateral, Thin Shell Element

2D

NOT SUPPORTED

• Element 5

Beam Column

1D

Bar/2

• Element 6

Two-Dimensional Plane Strain Triangle

2D

Tri/3

• Element 7

Three-Dimensional Arbitrary Distorted Brick 3D

Wedge/6, Hex/8

• Element 8

Curved Triangular Shell

2D

NOT SUPPORTED

• Element 9

Three-Dimensional Truss

1D

Bar/2

• Element 10

Arbitrary Quadrilateral Axisymmetric Ring

2D

Quad/4

• Element 11

Arbitrary Quadrilateral Plane-Strain

2D

Quad/4

Chapter 2: Building A Model 127 Element Properties

Element #

Main Index

Description

Dimension

Topologies

• Element 12

Friction and Gap Link Element

1D

Bar/2

• Element 13

Open Section Thin-Walled Beam

1D

Bar/2

• Element 14

Thin Walled Beam in Three Dimensions without Warping

1D

Bar/2

• Element 15

Axisymmetric Shell, Isoparametric Formulation

1D

Bar/2

• Element 16

Curved Beam in Two-dimensions, Isoparametric Formulation

1D

Bar/2

• Element 17

Constant Bending, Three-node Elbow Element

1D

NOT SUPPORTED

• Element 18

Four-Node, Isoparametric Membrane

2D

Tri/3, Quad/4

• Element 19

Generalized Plane Strain Quadrilateral

2D

Tri/3, Quad/4

• Element 20

Axisymmetric Torsional Quadrilateral

2D

Tri/3, Quad/4

• Element 21

Three-Dimensional 20-Node Brick

3D

Wedge/15, Hex/20

• Element 22

Quadratic Thick-Shell Element

2D

Tri/6, Quad/8

• Element 23

Three-dimensional 20-node Rebar Element

3D

NOT SUPPORTED

• Element 24

Curved Quadrilateral Shell Element

2D

NOT SUPPORTED

• Element 25

Thin Walled Beam in Three Dimensions

1D

Bar/2

• Element 26

Plane Stress, Eight-Node Distorted Quadrilateral

2D

Quad/8

• Element 27

Plane Strain, Eight-Node Distorted Quadrilateral

2D

Quad/8

• Element 28

Axisymmetric, Eight-Node Distorted Quadrilateral

2D

Quad/8

• Element 29

Generalized Plane Strain, Distorted Quadrilateral

2D

Tri/6, Quad/8

• Element 30

Membrane, Eight-Node Distorted Quadrilateral

2D

Quad/8

• Element 31

Elastic Curved Pipe (Elbow) / Straight Beam 1D

Bar/2

• Element 32

Plane Strain Eight-Node Distorted Quadrilateral, Herrmann Formulation

2D

Quad/8

• Element 33

Axisymmetric, Eight-Node Distorted Quadrilateral, Herrmann Formulation

2D

Quad/8

• Element 34

Generalized Plane Strain Distorted Quadrilateral, Herrmann Formulation

2D

Tri/6, Quad/8

128 Marc Preference Guide Element Properties

Element #

Main Index

Description

Dimension

Topologies

• Element 35

Three-Dimensional 20-Node Brick, Herrmann Formulation

3D

Wedge/15, Hex/20

• Element 36

Three-Dimensional Link (Heat Transfer Element)

1D

Bar/2

• Element 37

Arbitrary Planar Triangle (Heat Transfer Element)

2D

Tri/3

• Element 38

Arbitrary Axisymmetric Triangle (Heat Transfer Element)

2D

Tri/3

• Element 39

Planar Bilinear Quadrilateral (Heat Transfer Element)

2D

Quad/4

• Element 40

Axisymmetric Bilinear Quadrilateral Element (Heat Transfer Element)

2D

Quad/4

• Element 41

Eight-Node Planar Biquadratic Quadrilateral (Heat Transfer Element)

2D

Quad/8

• Element 42

Eight-Node Axisymmetric Biquadratic Quadrilateral (Heat Transfer Element)

2D

Quad/8

• Element 43

Three-Dimensional Eight-Node Brick (Heat Transfer Element)

3D

Wedge/6, Hex/8

• Element 44

Three-Dimensional 20-Node Brick (Heat Transfer Element)

3D

Wedge/15, Hex/20

• Element 45

Curved Timoshenko Beam in a Plane

1D

Bar/3

• Element 46

Eight-node Plane Strain Rebar Element

2D

NOT SUPPORTED

• Element 47

Generalized Plane Strain Rebar Element

2D

NOT SUPPORTED

• Element 48

Eight-node Axisymmetric Rebar Element

2D

NOT SUPPORTED

• Element 49

Finite Rotation Linear Thin Shell Element

2D

Tri/6

• Element 50

Three-Node Linear Heat Transfer Shell Element

2D

Tri/3

• Element 51

Cable Element

1D

Bar/2

• Element 52

Elastic Beam

1D

Bar/2

• Element 53

Plane Stress, Eight-Node Distorted Quadrilateral with Reduced Integration

2D

Tri/6, Quad/8

• Element 54

Plane Strain, Eight-Node Distorted Quadrilateral with Reduced Integration

2D

Tri/6, Quad/8

• Element 55

Axisymmetric, Eight-Node Distorted Quadrilateral with Reduced Integration

2D

Tri/6, Quad/8

• Element 56

Generalized Plane Strain, Distorted Quadrilateral with Reduced Integration

2D

Tri/6, Quad/8

Chapter 2: Building A Model 129 Element Properties

Element #

Main Index

Description

Dimension

Topologies

• Element 57

Three-Dimensional 20-Node Brick with Reduced Integration

3D

Wedge/15, Hex/20

• Element 58

Plane Strain Eight-Node Distorted Quadrilateral with Reduced Integration Herrmann Formulation

2D

Tri/6, Quad/8

• Element 59

Axisymmetric, Eight-Node Distorted Quadrilateral with Reduced Integration, Herrmann Formulation

2D

Tri/6, Quad/8

• Element 60

Generalized Plane Strain Distorted Quadrilateral with Reduced Integration, Herrmann Formulation

2D

Tri/6, Quad/8

• Element 61

Three-Dimensional, 20-Node Brick with 3D Reduced Integration - Herrmann Formulation

Tet/10, Wedge/15, Hex/20

• Element 62

Axisymmetric, Eight-node Quadrilateral for Arbitrary Loading (Fourier)

2D

Tri/6, Quad/8

• Element 63

Axisymmetric, Eight-node Distorted Quadrilateral for Arbitrary Loading, Herrmann Formulation (Fourier)

2D

Tri/6, Quad/8

• Element 64

Isoparametric, Three-Node Truss

1D

Bar/3

• Element 65

Heat Transfer Element, Three-Node Link

1D

Bar/3

• Element 66

Eight-Node Axisymmetric Herrmann Quadrilateral with Twist

2D

Tri/6, Quad/8

• Element 67

Eight-Node Axisymmetric Quadrilateral with Twist

2D

Tri/6,Quad/8

• Element 68

Elastic, Four-Node Shear Panel

2D

Quad/4

• Element 69

Eight-Node Planar Biquadratic Quadrilateral w/ Reduced Integration (Heat Transfer Element)

2D

Tri/6, Quad/8

• Element 70

Eight-Node Axisymmetric Biquadrilateral with Reduced Integration (Heat Transfer Element)

2D

Tri/6, Quad/8

• Element 71

Three-Dimensional 20-Node Brick with 3D Reduced Integration (Heat Transfer Element)

Wedge/15, Hex/20

• Element 72

Bilinear Constrained Shell Element

2D

Quad/8

• Element 73

Axisymmetric, Eight-node Quadrilateral for Arbitrary Loading with Reduced Integration (Fourier)

2D

Tri/6, Quad/8

130 Marc Preference Guide Element Properties

Element #

Main Index

Description

Dimension

Topologies

• Element 74

Axisymmetric, Eight-node Distorted Quadrilateral for Arbitrary Loading, Herrmann Formulation, with Reduced Integration (Fourier)

2D

Tri/6, Quad/8

• Element 75

Bilinear Thick-Shell Element

2D

Tri/3, Quad/4

• Element 76

Thin-Walled Beam in Three Dimensions without Warping

1D

Bar/3

• Element 77

Thin-Walled Beam in Three Dimensions including Warping

1D

Bar/3

• Element 78

Thin-Walled Beam in Three Dimensions without Warping

1D

Bar/2

• Element 79

Thin-Walled Beam in Three Dimensions including Warping

1D

Bar/2

• Element 80

Arbitrary Quadrilateral Plane Strain, Herrmann Formulation

2D

Quad/4/5

• Element 81

Generalized Plane Strain Quadrilateral, Herrmann Formulation

2D

Tri/3, Quad/4

• Element 82

Arbitrary Quadrilateral Axisymmetric Ring, Herrmann Formulation

2D

Quad/4/5

• Element 83

Axisymmetric Torsional Quadrilateral, Herrmann Formulation

2D

Tri/3, Quad/4/5

• Element 84

Three-Dimensional Arbitrary Distorted Brick, Herrmann Formulation

3D

Wedge/6/7, Hex/8/9

• Element 85

Four-Node Bilinear Shell (Heat Transfer Element)

2D

Quad/4

• Element 86

Eight-Node Curved Shell (Heat Transfer Element)

2D

Tri/6, Quad/8

• Element 87

Three-Node Axisymmetric Shell (Heat Transfer Element)

1D

Bar/3

• Element 88

Two-Node Axisymmetric Shell (Heat Transfer Element)

1D

Bar/2

• Element 89

Thick Curved Axisymmetric Shell

1D

Bar/3

• Element 90

Thick Curved Axisymmetric Shell--for Arbitrary Loading (Fourier)

1D

Bar/3

• Element 91

Linear Plane Strain Semi-infinite Element

2D

Quad/4

• Element 92

Linear Axisymmetric Semi-infinite Element

2D

Quad/4

• Element 93

Quadratic Plane Strain Semi-infinite Element 2D

Quad/8

Chapter 2: Building A Model 131 Element Properties

Element #

Main Index

Description

Dimension

Topologies

• Element 94

Quadratic Axisymmetric Semi-infinite Element

2D

Quad/8

• Element 95

Axisymmetric Quadrilateral with Bending.

2D

Tri/3, Quad/4

• Element 96

Axisymmetric, Eight-node Distorted Quadrilateral with Bending

2D

Tri/6, Quad/8

• Element 97

Special Gap and Friction Link for Bending

1D

Bar/2

• Element 98

Elastic Beam with Transverse Shear

1D

Bar/2

• Element 99

Heat Transfer Link Element Compatible with Beam Elements

2D

NOT SUPPORTED

• Element 100

Heat Transfer Link Element Compatible with Beam Elements

2D

NOT SUPPORTED

• Element 101

Six-node Plane Semi-infinite Heat Transfer Element

2D

Quad/4

• Element 102

Six-node Axisymmetric Semi-infinite Heat Transfer Element

2D

Quad/4

• Element 103

Nine-node Planar Semi-infinite Heat Transfer 2D Element

Quad/8

• Element 104

Nine-node Axisymmetric Semi-infinite Heat Transfer Element

Quad/8

• Element 105

Twelve-node 3-D Semi-infinite Heat Transfer 3D Element

Hex/8

• Element 106

Twenty-seven-node 3-D Semi-infinite Heat Transfer Element

3D

Hex/20

• Element 107

Twelve-node 3-D Semi-infinite Stress Element

3D

Hex/8

• Element 108

Twenty-seven-node 3-D Semi-infinite Stress Element

3D

Hex/20

• Element 109

Eight-node 3-D Magnetostatic Element

3D

Hex/8

• Element 110

Twelve-node 3-D Semi-infinite Magnetostatic Element

3D

Hex/12

• Element 111

Arbitrary Quadrilateral Planar Electromagnetic

2D

Quad/4

• Element 112

Arbitrary Quadrilateral Axisymmetric Electromagnetic Ring

2D

Quad/4

2D

132 Marc Preference Guide Element Properties

Element #

Main Index

Description

Dimension

Topologies

• Element 113

Three-dimensional Electromagnetic Arbitrarily

3D

Hex/8

• Element 114

Plane Stress Quadrilateral, Reduced Integration

2D

Tri/3, Quad/4

• Element 115

Arbitrary Quadrilateral Plane Strain, Reduced 2D Integration

Tri/3, Quad/4

• Element 116

Arbitrary Quadrilateral Axisymmetric Ring, Reduced Integration

2D

Tri/3 Quad/4

• Element 117

Three-Dimensional Arbitrary Distorted Brick, Reduced Integration

3D

Wedge/6, Hex/8

• Element 118

Arbitrary Quadrilateral Plane Strain, Incompressible Formulation with Reduced Integration

2D

Quad/4/5

• Element 119

Arbitrary Quadrilateral Axisymmetric Ring, Incompressible Formulation with Reduced Integration

2D

Quad/4/5

• Element 120

Three-Dimensional Arbitrarily Distorted Brick, Incompressible Reduced Integration

3D

Wedge/6/7, Hex/8/9

• Element 121

Planar Bilinear Quadrilateral, Reduced Integration (Heat Transfer Element)

2D

Tri/6, Quad/4

• Element 122

Axisymmetric Bilinear Quadrilateral, 2D Reduced Integration (Heat Transfer Element)

Tri/6, Quad/4

• Element 123

Three-Dimensional Eight-Node Brick, 3D Reduced Integration (Heat Transfer Element)

Wedge/6, Hex/8

• Element 124

Plane Stress, Six-Node Distorted Triangle

2D

Tri/6

• Element 125

Plane Strain, Six-Node Distorted Triangle

2D

Tri/6

• Element 126

Axisymmetric, Six-Node Distorted Triangle

2D

Tri/6

• Element 127

Three-Dimensional Ten-Node Tetrahedron

3D

Tet/10

• Element 128

Plane Strain, Six-Node Distorted Triangle, Herrmann Formulation

2D

Tri/6

• Element 129

Axisymmetric, Six-Node Distorted Triangle, Herrmann Formulation

2D

Tri/6

• Element 130

Three-Dimensional Ten-Node Tetrahedron, Herrmann Formulation

3D

Tet/10

• Element 131

Planar, Six-Node Distorted Triangle (Heat Transfer Element)

2D

Tri/6

Chapter 2: Building A Model 133 Element Properties

Main Index

Element #

Description

Dimension

Topologies

• Element 132

Axisymmetric, Six-Node Distorted Triangle (Heat Transfer Element)

2D

Tri/6

• Element 133

Three-Dimensional Ten-Node Tetrahedron (Heat Transfer Element)

3D

Tet/10

• Element 134

Three-Dimensional Four-Node Tetrahedron

3D

Tet/4

• Element 135

Three-Dimensional Four-Node Tetrahedron (Heat Transfer Element)

3D

Tet/4

• Element 136

Six-node Wedge

3D

NOT SUPPORTED

• Element 137

Six-node Wedge Heat Transfer

3D

NOT SUPPORTED

• Element 138

Bilinear Thin-triangular Shell Element

2D

Tri/3

• Element 139

Bilinear Thin-shell Element

2D

Quad/4

• Element 140

Bilinear Thick-shell Element with Reduced Integration

2D

Tri/3, Quad/4

• Element 141

Heat Transfer Shell

2D

NOT SUPPORTED

• Element 142

Eight-node Axisymmetric Rebar Element with Twist

2D

NOT SUPPORTED

• Element 143

Four-node Plane Strain Rebar Element

2D

NOT SUPPORTED

• Element 144

Four-node Axisymmetric Rebar Element

2D

NOT SUPPORTED

• Element 145

Four-node Axisymmetric Rebar Element with Twist

2D

NOT SUPPORTED

• Element 146

Three-dimensional 8-node Rebar Element

3D

NOT SUPPORTED

• Element 147

Four-node Rebar Membrane

2D

Quad/4

• Element 148

Eight-node Rebar Membrane

2D

Quad/8

• Element 149

Three-dimensional, Eight-node Composite Brick Element

3D

Wed/6, Hex/8

• Element 150

Three-dimensional, Twenty-node Composite Brick Element

3D

Wed/15, Hex/20

• Element 151

Quadrilateral, Plane Strain, Four-node Composite Element

2D

Tri/3, Quad/4

• Element 152

Quadrilateral, Axisymmetric, Four-node Composite Element

2D

Tri/3, Quad/4

• Element 153

Quadrilateral, Plane Strain, Eight-node Composite Element

2D

Tri/6, Quad/8

• Element 154

Quadrilateral, Axisymmetric, Eight-node Composite Element

2D

Tri/6, Quad/8

134 Marc Preference Guide Element Properties

Main Index

Element #

Description

Dimension

Topologies

• Element 155

Plane Strain, Low-order, Triangular Element, Herrmann Formulations

2D

Tri/3/4

• Element 156

Axisymmetric, Low-order, Triangular Element, Herrmann Formulations

2D

Tri/3/4

• Element 157

Three-dimensional, Low-order, Tetrahedron, Herrmann Formulations

3D

Tet/4/5

• Element 158

Three-node Triangular Membrane Element

2D

NOT SUPPORTED

• Element 159

Four-node Bilinear Thick Shell Element

2D

NOT SUPPORTED

• Element 160

4-node Piezo Electric Plane Stress Element

2D

Quad/4

• Element 161

4-node Piezo Electric Plane Strain Element

2D

Quad/4

• Element 162

4-node Piezo Electric Axisymmetric Element 2D

Quad/4

• Element 163

8-node Piezo Electric Brick Element

3D

Hex/8

• Element 164

4-node Piezo Electric Tetrahedron Element

3D

Tet/4

• Element 165

Two-node Plane Strain Rebar Membrane

1D

Bar/2

• Element 166

Two-node Axisymmetric Rebar Membrane

1D

Bar/2

• Element 167

Two-node Axisymmetric Rebar Membrane w/ Twist

1D

Bar/2

• Element 168

Three-node Plane Strain Rebar Membrane

1D

Bar/3

• Element 169

Three-node Axisymmetric Rebar Membrane

1D

Bar/3

• Element 170

Three-node Axisymmetric Rebar Membrane w/ Twist

1D

Bar/3

• Element 171

Two-node 2-D Cavity Surface Element

1D

NOT SUPPORTED

• Element 172

Two-node Axisymmetric Cavity Surface Element

1D

NOT SUPPORTED

• Element 173

Three-node 3-D Cavity Surface Element

2D

NOT SUPPORTED

• Element 174

Four-node 3-D Cavity Surface Element

2D

NOT SUPPORTED

• Element 175

Eight-node Composite Heat Transfer Brick Element

3D

Wed/6, Hex/8

• Element 176

Twenty-node Composite Heat Transfer Brick Element

3D

Wed/15, Hex/20

• Element 177

Four-node Plane Strain Composite Heat Transfer Element

2D

Tri/3, Quad/4

• Element 178

Four-node Axisymmetric Composite Heat Transfer Element

2D

Tri/3, Quad/4

• Element 179

Eight-node Plane Strain Composite Heat Transfer Element

2D

Tri/6, Quad/8

Chapter 2: Building A Model 135 Element Properties

Element #

Description

Dimension

Topologies

• Element 180

Eight-node Axisymmetric Composite Heat Transfer Element

2D

Tri/6, Quad/8

• Element 181

3D Magnetostatic Tetrahedron

3D

Tet/4

• Element 182

3D Magnetostatic Tetrahedron

3D

Tet/10

• Element 183

3D Magnetostatic Current Carrying Wire

3D

Bar/2

Element Input Properties This is an example of one of many Input Properties forms that can appear when defining element properties.

Main Index

136 Marc Preference Guide Element Properties

For a list of supported Marc element types, see (p. 126). The input properties for each Marc element type are listed below. They are listed in order of dimension as follows: 0D Elements

2D Elements

1D Elements

2D Solid Elements

1D Shell/Membrane Elements

3D Elements

0D Elements Mass This input data creates the MASSES keyword option. These act in the analysis coordinate frame of the node. Property Name

Description

Translational Inertia, X/Y/Z

Defines the concentrated mass values for translational degrees-of-freedom. These properties are optional and can be entered either as real constants or references to existing field definitions. They appear on the third card of the MASSES option.

Rotational Inertia XX/YY/ZZ

Defines the rotational inertia values for rotational degrees-offreedom. These properties are optional and can be entered either as real constants or references to existing field definitions. They appear on the third card of the MASSES option.

Spring/Damper See Spring/Damper under 1D Elements.

1D Elements Beams, Bars, Pipes, Trusses This input data creates the Marc element types 5, 9, 13, 14, 16, 25, 31, 45, 52, 64, 76, 77, 78, 79, or 98. The properties entered into the Input Properties form fill out the necessary information in the GEOMETRY and/or BEAM SECT and NODAL THICKNESS keyword options of the Marc input file. The properties presented to you in the form are dependent on the element type to be created. Spatial fields can be defined and referenced in various properties to denote that a property value varies with element position or length such as thickness or cross sectional area. See Fields - Tables for more information.

Main Index

Chapter 2: Building A Model 137 Element Properties

Note that the General Beam selection behaves differently than the other selections such as Elastic Beam, Planar Beam or Thin-Walled Beam. The General Beam attempts to be smart and determine which beam element is the most appropriate for your particular application, whereas the other beam selection types will give you the beam that you ask for. If you don’t know what Marc beam element to use, we suggest you simply use General Beam and let the application determine the best fit. The logic at the right is used to determine the appropriate element type:

Main Index

138 Marc Preference Guide Element Properties

A list of all properties for beam/bar/pipe/ truss elements are given below. Only those applicable to the particular type of element appears on the Input Properties form.

Main Index

Property Name

Description

Section Name

Defines the section to be used from a list of sections created or stored in the Beam Library. A list of all sections (currently in the database) is displayed. Either select from the list or type in the name. This property is required and only appears for General Beam. For other methods of assigning beam properties, a button at the bottom of the form allows you to select an existing beam section, but the section name is not associated to the property itself as is the case for General Beam.

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

XZ Plane Definition

Defines the orientation of the beam elements. This vector determines the plane that contains the local x-axis and the beam axis. The components of the vector appear in the EGEOM4, 5, and 6 data fields of the GEOMETRY option. This property is required.

Center of Curvature

Defines the center of the bend radius by referencing the ID of an existing node. The coordinates of the node appear in the EGEOM3, 4, and 5 data fields of the GEOMETRY option. This property is required for curved beams.

Cross-Sectional Area

Defines the area of the beam or truss cross section. It can be entered as a real constant or a reference to an existing field definition. For a truss element, the value appears in the EGEOM1 data field of the GEOMETRY option or in the second data field on the third card of the BEAM SECT option for beams/bars/pipes, and is a required property.

Section Radius (ave)

Defines the radius measured from the pipe center to the middle of the pipe wall. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM2 data field of the GEOMETRY option, and is a required property for pipe elements.

Chapter 2: Building A Model 139 Element Properties

Property Name

Description

Section Height

Defines the beam thickness either as element uniform or tapered based on the selected “Value Type.” Real Scalar: Each element will have a uniform thickness which can be entered as a real constant, or a reference to an existing field definition. The data appears in the EGEOM1 data field of the GEOMETRY option. Field at Nodes: Tapered elements will be created by referencing an existing field definition. The data appears on the third card of the NODAL THICKNESS option. This property is required.

Section Width

Defines the beam section area for Bar/2 elements or beam section width for Bar/3 elements. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM2 data field of the GEOMETRY option, and is a required property.

Pipe Thickness

Defines the pipe wall thickness for pipe elements. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM1 data field of the GEOMETRY option, and is a required property for pipe elements.

Shear Area-x

Defines the effective transverse shear area in the local x and y directions. They can be entered as a real constants or references to existing field definitions. The values appear in the sixth and seventh data fields on the third card of the BEAM SECT option.

Shear Area-y

Ixx Iyy

Izz (K factor)

Main Index

Defines the moments of inertia about the local x and y axes. They can be entered either as real constants or references to existing field definitions. The values appear in the fourth and fifth data fields on the third card of the BEAM SECT option, and are required properties. Defines the torsional stiffness factor. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the fifth data field on the third card of the BEAM SECT option, and is a required property.

140 Marc Preference Guide Element Properties

Property Name

Description

# Divisions ea Branch

Defines the number of divisions for each branch of the beam cross section for stress recovery. This data is entered as a list of integer constants - one value for each branch. The values appear on the third card of the BEAM SECT option, and are required properties. Each branch is divided (by you) into segments. The stress points of the section, that is, the points used by numerical integration of section stiffness and also for output of stress, are the segment division points. The end points of any branch are always stress points, and there must always be an even number of divisions (nonzero) in any branch. A maximum of 31 stress points (30 divisions) can be used in a complete cross-section, not counting branches of zero thickness.

X @ Begin 1st Branch

Defines the coordinates at the beginning of the first branch in the beam cross section. These real constants appear in the first and second data fields on the fourth card of the BEAM SECT option, and are required properties.

Y @ Begin 1st Branch [dx/ds @ Branch Begin] [dy/ds @ Branch Begin]

Thkns @ Branch Begin

Defines the thickness at the beginning of each branch. These real constants must have values that are greater than or equal to zero (branches with zero thickness can be used to double back over existing branches). They are entered on the fifth card of the BEAM SECT option, and are required properties.

X @ Branch End

Defines the coordinates at the end of each branch in the beam cross section. These real constants appear in the fifth and sixth data fields on the fourth card of the BEAM SECT option, and are required properties. The end branch location is always the beginning branch location for the next branch. In some cases, to define a proper cross section, the branches must overlap back onto themselves. In this case, the overlapping branch is assigned a zero thickness.

Y @ Branch End

Main Index

Defines the direction cosines of the tangent at the beginning of each branch relative to the local x and y axes. These lists of real constants are optional. The default directs the branch in a straight path between its ends and only operates when neither list is provided. When values are entered, they must be greater than or equal to -1.0 and less than or equal to +1.0. This data appears on the fourth card of the BEAM SECT option.

Chapter 2: Building A Model 141 Element Properties

Property Name

Description

[dx/ds @ Branch End]

Defines the direction cosines of the tangent at the end of each branch relative to the local x and y axes. These lists of real constants are optional. The default directs the branch in a straight path between its ends and only operates when neither list is provided. When values are entered, they must be greater than or equal to -1.0 and less than or equal to +1.0. This data appears on the fourth card of the BEAM SECT option.

[dy/ds @ Branch End]

Main Index

Thkns @ Branch End

Defines the thickness at the end of each branch. These real constants must have values that are greater than or equal to zero (branches with zero thickness can be used to double back over existing branches). They are entered on the fifth card of the BEAM SECT option, and are required properties. If the thickness at the beginning of the branch is nonzero and the end is defined as zero, the branch is assumed to be of constant thickness.

[Contact Beam Radius]

Defines the radius of the beam for beam-to-beam contact purposes. This value is unnecessary for MSC.Marc versions 2001 and earlier in which the contact distance between touching beams is calculated automatically. However this radius is required for Marc 2003 if beam-to-beam contact is involved. The radius is entered in the 7th filed of the GEOMETRY option.

[Branch Length]

Defines the length of each branch. These real constants are optional. The default value is equal to the straight distance between the ends of the branch. They are entered on the fifth card of the BEAM SECT option.

[Transverse Shear]

If this is set to Parabolic, then the TSHEAR parameter is written, which changes the transverse shear model from constant through the thickness to a parabolic representation for planar beam, element type 45.

[Rigidity]

In a Coupled analysis, if this is set to Rigid, the element exhibits only heat transfer capabilities and becomes structurally rigid.

142 Marc Preference Guide Element Properties

Note:

For most beam elements, you can select existing section and property data from the Beam Library which is an application under the Tools pull down menu. When this is done, the appropriate data boxes are filled in with the section properties automatically. In some cases this is property data while others it is branch information. For the General Beam, all this information is filled out, however, only the data needed for the selected element type is written to the Marc input file. For arbitrary beam section types, the Beam Library allows entry in the form of branch (or centerline) data. It is highly recommended to use the Beam Library to define this data as it is much easier.

Spring/Damper This input data creates the SPRINGS keyword option in the Marc input file. Properties that can vary spatially (or nonspatially) are defined by referencing a spatial (or nonspatial) field (table). See Fields Tables for more information. Currently there are three selection for creating the SPRINGS keyword: Spring/Damper, Spring, or Damper. The latter two are somewhat obsolete in that they only allow you to define a linear spring or a linear damper. The Spring/Damper allows you to define both a linear or nonlinear combination spring/damper and is thus much more versatile and the recommended method. Nonlinear springs which reference nonspatial fields of force vs deflection are only valid for Marc version 2003 and beyond. Spring/dampers used in Thermal analysis only act as rigid links with thermal conduction. Linear spring/dampers cannot accept spatially or nonspatially varying fields. Property Name

Description

Dof at Node 1

Defines the degree-of-freedom to use at each end of the spring element. They are entered in the second and fourth data fields on the second card of the SPRINGS option, and are required properties. For 0D Objects, the D0f at Node 2 is not available and thus not entered to flag a grounded spring/damper.

Dof at Node 2

Stiffness

Main Index

Defines the spring stiffness. It can be entered either as a real constant or a reference to an existing nonspatial field definition of Force vs Deflection or Stiffness vs. Deflection for nonlinear springs only, which can vary with time and/or temperature also. The scalar value or unity appears in the 5th field on the 2nd data block of the SPRINGS option with a reference to a TABLE entry. The old, 1d linear Spring definition can accept a spatially varying field in which case multiple SPRINGS options are written to describe the spatial variation of stiffness.

Chapter 2: Building A Model 143 Element Properties

Main Index

Property Name

Description

Damping Coefficient

Defines the damping coefficient. It can be entered either as a real constant or a reference to an existing nonspatial field definition of Force vs Velocity or Coefficient vs. Velocity for nonlinear dampers only, which can vary with time and/or temperature also. The scalar value or unity appears in the 6th field of the 2nd data block of the SPRINGS option with a reference to a TABLE entry. The old, 1d linear Damper definition can accept a spatially varying field in which case multiple SPRINGS options are written to describe the spatial variation of damping.

Initial Force

This is a real scalar value of initial force in the spring. This cannot vary via a field definition. The scalar value appears in the 7th field of the 2nd data block of the SPRINGS option

Thermal Conduction

Defines the thermal conductivity for Thermal or Coupled analyses. It can be entered either as a real constant or a reference to an existing nonspatial field definition of Flux vs Temperature or Conduction vs. Temperature for nonlinear links only, which can vary with time also. The scalar value or unity appears in the 8th field on the 2nd data block of the SPRINGS option with a reference to a TABLE entry.

Numerical Stabalizer

This is a flag that, if set, will cause the spring to act as a numerical stabalizer and the spring force will always be set to zero.

144 Marc Preference Guide Element Properties

Gaps This input data creates Marc element type 12 and 97 (Friction and Gap Link), and the associated GAP DATA keyword options. The 7th data field on the third card of the GAP DATA option is set to zero (0) to indicate fixed direction input or to one (1) to indicate true distance input. The two connectivity nodes become the first and fourth nodes of the element. The second and third nodes are created during translation. The 3rd node uses the defaults for its coordinates, which define the friction directions. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. Property Name

Description

Init Open or Closed

Indicates the condition of the gap for the first iteration of the analysis. This data is optional and will default to initially open if not defined. It is entered in the 8th data field on the third card of the GAP DATA option.

Limiting Distance

Indicates that the “Limiting Distance” restricts the minimum or maximum opening of the gap. This property is optional and defaults to the minimum limit type. For “Closure Distance,” this data is place in the 1st field of the GAP DATA option.

Closure Distance

Main Index

Min or Max Limit Type

Defines a minimum or maximum restriction on the gap distance based on the selection made for “Min or Max Limit Type.” It can be entered either as a real constant or a reference to an existing field definition. The value appears in the first data field on the third card of the GAP DATA option.

Friction Coefficient

Defines the sliding friction coefficient when the gap is closed. This property is optional and defaults to zero when not defined. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the second data field on the third card of the GAP DATA option.

Chapter 2: Building A Model 145 Element Properties

Property Name

Description

K Normal (closed)

Defines the normal and tangential stiffness of the element when the gap is closed. They can be entered either as real constants or references to existing field definitions. The values appear in the third and fourth data fields on the third card of the GAP DATA option.

K Tangent (closed)

Closure Direction

This is a vector that defines the closure direction and used only for Fixed Direction gaps. Note that this element is actually a 4 node element although only Bar/2 topologies are allowed. The two internal nodes are generated automatically by the translation. The first and fourth nodes couple to the rest of the structure while node 2 is the gap node. It has one degree of freedom, Fn, the force being carried across the link. The coordinate data of this node is used to input the direction of the gap closure direction and determined from this vector. Node 3 is the frictional node, which is automatically supplied by the translator. This property is required.

Cable This input data creates Marc element type 51 (Cable Element). The GEOMETRY option is used to define the cross-sectional area and the initial length. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information.

Main Index

Property Name

Description

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Cross-Sectional Area

Defines the area of the cable cross section. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM1 data field of the GEOMETRY option, and is a required property.

Initial Stress

Defines the initial stress in the cable elements.This property is optional and will default to zero when not defined. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM3 data field of the GEOMETRY option.

Element Length

Defines the initial length of the cable elements. This property is optional and will default to the straight distance between the ends of the cable element. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM2 data field of the GEOMETRY option.

146 Marc Preference Guide Element Properties

Links This input data creates Marc element types 36 or 65. The GEOMETRY option is used to define the crosssectional area for Conduction Links and the area where the element acts and the convective/radiative properties of the boundary for Convect/Radiation Links. Only the necessary properties are presented depending on the link type requested. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. Property Name

Description

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Cross-Sectional Area

Defines the area of the link cross section. It can be entered either as a real constant, or a reference to an existing field definition. The value appears in the EGEOM1 data field of the GEOMETRY option and is required.

Emissivity

Defines the emissivity between the two end nodes of this link. This is entered in the EGEOM2 data field of the GEOMETRY option. This value can be either a real constant or a reference to an existing field definition. This property is optional.

Stefan-Boltz Constant

Defines the Stefan-Boltzmann radiation constant. It can be entered either as a real constant or a reference to an existing field definition.The value is entered in the EGEOM3 data field of the GEOMETRY option. This property is optional.

Abs Temp Conversion

Defines the absolute temperature conversion factor for the radiative boundary conditions. It can be entered either as a real constant or a reference to an existing field definition. The value is entered in the EGEOM4 data field of the GEOMETRY option. This property is optional.

Film Coefficient

Defines the convective film coefficient for convective boundary conditions. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the EGEOM5 data field of the GEOMETRY option. This property is optional.

1D Shell/Membrane Elements Axisymmetric Shell This input data creates Marc element types 1, 15, 89 and 90 for structural elements or 87 and 88 for heat transfer elements. The properties entered into the Input Properties form fill out the necessary information in the GEOMETRY and NODAL THICKNESS keyword options of the Marc input file. The properties

Main Index

Chapter 2: Building A Model 147 Element Properties

presented to you in the form are dependent on the element type to be created. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. A list of all properties for beam/bar/pipe/truss elements are given below: Property Name

Description

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Thickness

For non-laminated axisymmetric shells, defines the shell thickness either as an element uniform or tapered based on the selected Value Type: Real Scalar: Each element will have a uniform thickness which can be entered as a real constant or a reference to an existing field definition. The data appears in the EGEOM1 data field of the GEOMETRY option. Field at Nodes: Tapered elements will be created by referencing an existing field definition. The data appears on the third card of the NODAL THICKNESS option. This property is required.

[Rigidity]

In a Coupled analysis, if this is set to Rigid, the element exhibits only heat transfer capabilities and becomes structurally rigid.

[Temperature Distribution]

In a Coupled analysis, if this is set to Quadratic, shell element temperatures will have 3 degrees-of-freedom (top, bottom, middle) as opposed to only two (top, bottom). The HEAT parameter is written to indicate this.

1D Rebar Membrane This input data creates Marc rebar membrane element types 165 to 170, which are either plane strain or axisymmetric type elements for use in inserting into 2D solid plane strain or axisymmetric elements to define rebar layers. The properties entered into the Input Properties form fill out the necessary information in the REBAR and INSERT keyword options of the Marc input file. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. A list of all properties for rebar membrane elements are given below:

Main Index

148 Marc Preference Guide Element Properties

Main Index

Property Name

Description

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Area

Defines the cross sectional area of each rebar in the layer. A spatially varying field can be provided if this varies along the length of the layer. Entered in the 3rd field of the 4th data block of the REBAR option. A spatial field can be entered if the Area varies from one location to another. In this case the 5th data block is also written.

Spacing

Defines the spacing of the rebar cords in the layer. A spatially varying field can be provided if this varies along the length of the layer. Entered in the 4th field of the 4th data block of the REBAR option. A spatial field can be entered if the Spacing varies from one location to another. In this case the 5th data block is also written.

Orientation

Defines the orientation angle of the rebar cords in the layer relative to the Reference Axis. This is the angle between the rebar and the projection of the reference axis on the rebar layer plane. A spatially varying field can be provided if this varies along the length of the layer. Entered in the 5th field of the 4th data block of the REBAR option. A spatial field can be entered if the Orientation varies from one location to another. In this case the 5th data block is also written.

[Reference Axis]

This is used to define the orientation angle. The reference axis is defined as a vector which is then projected onto the rebar layer plane. The orinetation angle is measured from this projection. If blank, it defaults to <1,0,0>, the x-axis. Reference axis is placed in the 4th-6th fields of the 3rd data block of the REBAR option.

[Microbuckle Factor]

If a factor is entered, this activates the microbuckle behavior of rebar cords in compression. The factor reduc es the rebar compression stiffness. A good default value is 0.02. Entry is flagged in the 8th field of the 3rd datablock of the REBAR option. The factor is placed in the 9th field.

Chapter 2: Building A Model 149 Element Properties

Property Name

Description

[Original Radius for Cylinder Expansion]

If entered, flags structure as an axisymmetric expansion of cylinders of bias plies with cords nearly inextensible relative to matrix material. Rebar properties are then calculated by Marc. The reference axis needs to be the symmetric axis of the orignal cylinder and needs to pass through the origin of the coordinates. Entry is flagged on the 3rd card of the 3rd data block and the radius is placed in the 6th field of th3 4th data block of the REBAR option.

[Create MFD File?]

If this is set to YES, then a MFD file is written with the geometric rebar information. This file can only be accessed and visualized by MSC.Marc Mentat currently.

Note:

You may either generate 1D rebar membrane elements manually through the Element Properties application by assigning properties directly to a generated 1D mesh. Or you may use the Rebar Definitions tool available from the Tools pull down menu, which will generate the mesh and assign the properties automatically for you. See Rebar Definition Tool at the end of this section. A list of elements into which these rebar membrane elements are to be inserted is automatically determined on translation based on geometric tolerance, which writes the INSERT option to the input file. Only one rebar layer may be defined by any one element property set. If more than one layer is necessary, create coincident elements and define another rebar property set to these elements.

Main Index

150 Marc Preference Guide Element Properties

2D Elements Shells, Plates, Membranes, Shear Panels This input data creates Marc element types 18, 22, 30, 49, 68, 72, 75, 138, 139, 140, 147, or 148 for structural elements and element types 50, 85, or 86 for heat transfer elements. The properties entered into the Input Properties form fill out the necessary information in the GEOMETRY and NODAL THICKNESS keyword options of the Marc input file. When a preferred element coordinate system is requested, the ORIENTATION option is generated. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. A list of all properties for shell/ plate/ membrane/ shear panel elements are given below: Property Name

Description

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Thickness

Defines the shell thickness either as element uniform or tapered based on the selected “Value Type.” Real Scalar: Each element will have a constant uniform thickness which can be entered as a real constant or a reference to an existing field definition. The data appears in the EGEOM1 data field of the GEOMETRY option. Element Nodal: Tapered elements will be created by referencing an existing field definition. The data appears on the third card of the NODAL THICKNESS option. This property is required.

Main Index

Orientation System

Selects the coordinate frame in which to define preferred material orientation. See Material Orientation for more explanation. Only CID (coordinate frame specification) is valid (or a flagging User Sub. ORIENT).

Orientation Angle

Defines the angle measured from the edge of the element or other reference line (vector) to the first preferred material direction of the element. It can be entered either as a real constant or a reference to an existing field definition. The value appears in the second data field on the third card of the ORIENTATION option. This property is optional. See Material Orientation for more explanation.

[Transverse Shear]

If this is set to Parabolic, then the TSHEAR parameter is written, which changes the transverse shear model from constant through the thickness to a parabolic representation for thich shells, element types 22, 75, and 140.

Chapter 2: Building A Model 151 Element Properties

Property Name

Description

[Rigidity]

In a Coupled analysis, if this is set to Rigid, the element exhibits only heat transfer capabilities and becomes structurally rigid.

[Temperature Distribution]

In a Coupled analysis, if this is set to Quadratic, shell element temperatures will have 3 degrees-of-freedom (top, bottom, middle) as opposed to only two (top, bottom). The HEAT parameter is written to indicate this.

2D Rebar Membrane This input data creates Marc rebar membrane element types 147 and 148 which are 4 and 8-noded quad type elements, respectively, for use in inserting into solid 3D elements (7, 21, 35, 57, 84, 117) to define rebar layers (or laying on top of 2D membrane elements (18,30). The properties entered into the Input Properties form fill out the necessary information in the REBAR and INSERT keyword options of the Marc input file. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. A list of all properties for rebar membrane elements are given above in 1D Rebar Membrane.

2D Solid Elements Axisymmetric, Plane Stress, Plane Strain This input data creates Marc element types 2, 3, 6, 10, 11, 19, 20, 26, 27, 28, 29, 32, 33, 34, 53, 54, 55, 56, 58, 59, 60, 62, 63, 66, 67, 73, 74, 80, 81, 82, 83, 91, 92, 93, 94, 95, 96, 114, 115, 116, 118, 119, 124, 125, 126, 128, 129, 151, 152, 153, 154, 155, or 156 for structural problems and 37, 38, 39, 40, 41, 42, 69, 70, 101, 102, 103, 104, 121, 122, 131, 132, 177, 178, 179, or 180 for heat transfer problems. The properties entered into the Input Properties form fill out the necessary information in the GEOMETRY keyword options of the Marc input file for thickness. When a preferred element coordinate system is requested, the ORIENTATION option is generated. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. A list of all properties for axisymmetric, plane stress, and plan strain elements are given below. Only those pertinent to the element type are presented.

Main Index

152 Marc Preference Guide Element Properties

Property Name

Description

Formulation Options

This is set to none by default. If you wish to use an Assumed Strain, Constant Volume or Both of these formulation options, you must set this with the pull down menu to the right of this input property widget. The appropriate flag is placed in the GEOMETRY option to turn these options on if selected. Note that under the Translation Parameter form, Assumed Strain and Constant Volume (or Dilatation) can be globally turned ON for all elements. If you wish these options to vary with element property definitions, you must turn them OFF globally in Job Parameters.

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Thickness

Defines the shell thickness either as element uniform or tapered based on the selected “Value Type.” Real Scalar: Each element will have a uniform thickness which can be entered as a real constant or a reference to an existing field definition. The data appears in the EGEOM1 data field of the GEOMETRY option. Element Nodal: Tapered elements will be created by referencing an existing field definition. The data appears on the third card of the NODAL THICKNESS option. This property is required.

Main Index

Orientation System

Selects the coordinate frame in which to define preferred material orientation. See Material Orientation for more explanation. Only CID (coordinate frame specification) is valid (or a flagging User Sub. ORIENT).

Orientation Angle

Same explanation as for 2D Elements above.

Thickness Change

Defines the thickness change at a position within the application region. The thickness change value is determined from the translational z component of the displacement boundary condition at the selected node.

Chapter 2: Building A Model 153 Element Properties

Property Name

Description

Rel. Surface Rotation

Defines the rotation of the application region’s top surface relative to its bottom surface. The rotation values are determined from the rotational x and y components of the displacement boundary condition at the selected node.

[Rigidity]

In a Coupled analysis, if this is set to Rigid, the element exhibits only heat transfer capabilities and becomes structurally rigid.

For lower-order laminated composite elements 151, and 152 (and 149) the following additional properties can be entered to define GASKET option (referred to as a GASKET material in the input file). If none of these properties are supplied, no GASKET option will be written.

Main Index

Property Name

Description

Loading Path

This data box that accepts a non-spatial field of Stress(pressure) vs. Closure Distance (a non-spatial displacement field). A table is written according to the TABLE option with gasket closure as the independent variable. The table ID is referenced in 2nd field of 3rd data block of the GASKET option.

Yield Pressure

Enter the yield pressure of the gasket material. This fills in the 1st field of 5th data block of GASKET option. Only a scalar value can be entered.

Tensile Modulus

Enter the tensile modulus of the gasket material. This fills in the 2nd field of 5th data block of GASKET option. Only a scalar value can be entered.

Transverse Shear Modulus

Enter the transverse shear modulus of the gasket material. This fills in the 3rd field of 5th data block of GASKET option. Only a scalar value can be entered.

Initial Gap

Enter the initial gap of the gasket material. This fills in the 4th field of 5th data block of GASKET option. Only a scalar value can be entered.

Unloading Path 1-10

These are 10 data boxes like Loading Path that can accept nonspatial fields or Stress vs. Closure, written to the TABLE option, and referenced in data block 4, fields 1-10, respectively. Multiple unloading paths are allowed to fully model the behavior of these gasket type materials where each load cycle can see a different unloading path.

154 Marc Preference Guide Element Properties

3D Elements Solid This input data creates Marc element types 7, 21, 35, 57, 61, 84, 107, 108,117, 120, 127, 130, 134, 149, 150, or 157 for structural problems and 43, 44, 71, 105, 106, 123, 133, 135, 175, or 176 for heat transfer problems. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information. When a preferred element coordinate system is requested, the ORIENTATION option is generated. Property Name

Description

Formulation Options

This is set to none by default. If you wish to use an Assumed Strain, Constant Volume or Both of these formulation options, you must set this with the pull down menu to the right of this input property widget. The appropriate flag is placed in the GEOMETRY option to turn these options on if selected. Note that under the Translation Parameter form, Assumed Strain and Constant Volume (or Dilatation) can be globally turned ON for all elements. If you wish these options to vary with element property definitions, you must turn them OFF globally in Job Parameters.

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Orientation System

Selects the coordinate frame in which to define the preferred material orientation. See Material Orientation for more explanation. Only CID (coordinate frame specification) is valid (or a flagging User Sub. ORIENT).

Orientation Angle

Defines the angle through which the Orientation System is rotated to define the preferred orientation. This property is optional. See Material Orientation for more explanation.

[Rigidity]

In a Coupled analysis, if this is set to Rigid, the element exhibits only heat transfer capabilities and becomes structurally rigid.

Note:

For solid laminated composite element 149, a GASKET option (material) can also be defined as explained in 2D Solid Elements.

Solid with Auto Tie This input data creates Marc element types 7, 21, or 57 to tie shells to solid elements. Properties that can vary spatially are defined by referencing a spatial field (table). See Fields - Tables for more information.

Main Index

Chapter 2: Building A Model 155 Element Properties

When a preferred element coordinate system is requested, the ORIENTATION option is generated. The thickness of the attached shell is placed in the GEOMETRY keyword option. Property Name

Description

Formulation Options

Same explanation as for 3D Elements Solid elements.

Material Name

Defines the material to be used. A list of all materials (currently in the database) is displayed. Either select from the list or type in the name, preceded by an “m:”. This property is required.

Orientation System

Selects the coordinate frame in which to define material orientation angle. See Material Orientation for more explanation. Only CID (coordinate frame specification) is valid (or a flagging User Sub. ORIENT).

Orientation Angle

Same explanation as for Solid elements above.

Tied Shell Thickness

Defines the transition thickness where the solid element attaches to the adjacent shell elements. It can be entered either as a real constant or a reference to an existing field definition. The value is entered in the EGEOM1 data field of the GEOMETRY option and is required.

Material Orientation Most 2D and 3D elements can have a preferred material orientation for orthotropic and anisotropic materials. This can be specified in a number of ways. The actual preferred orientation is measured from the given preferred directions based on the orientation angle given. The various scenarios that exist are: • No Orientation Angle or Orientation System - no ORIENTATION option written. In this

case, Marc will use its default preferred directions for 2D and 3D elements, which in most cases are defined by the element coordinate system. • Orientation Angle given with no Orientation System specified. For 2D elements the EDGE 1-

2 option is used in the ORIENTATION option. Only the EDGE 1-2 and the Orientation Angle are written to the ORIENTATION option. Marc determines the preferred directions from this data. The angle is measured from this element edge (projected onto the elements tangent plane and rotated about the tangent plane normal) and defines the 1st preferred direction. The 3rd preferred direction is the tangent plane normal and the 2nd preferred direction is the cross product of the 3rd and 1st preferred directions. This option is not practical because generally the material orientation does not change, but the element edges and their orientations relative to the actual material orientation do, thereby making this option useless unless the element 1-2 edge points the same direction for every element. For 3D elements the 3D ANISO option is used in the ORIENTATION option. If no orientation system is specified, then the global system is assumed. The 1st, 2nd, and 3rd preferred direction are the x, y, and z-axes, respectfully rotated about the z-axis by the amount of the Orientation Angle specified. The rotated x and y-axis vectors are written to the ORIENTATION option.

Main Index

156 Marc Preference Guide Element Properties

• Orientation System given with or without the Orientation Angle. A coordinate system must be

selected. For 2D elements, the UU PLANE option is written to the ORIENTATION option. The two vectors written to the ORIENTATION option are the x and z-axes of the Orientation System for rectangular systems. Again, Marc determines the preferred directions from this information. The 1st preferred direction is determined by the intersection of this x-z plane with the element tangent plane, rotated through the Orientation Angle about the element tangent plane’s normal vector. The 3rd preferred direction is the element tangent plane’s normal vector. And the 2nd preferred direction is the cross product of the 3rd and 1st preferred directions. Display of the 1st preferred material direction is a single vector at the centroid of the element in the element tangent plane. A warning message is issued if the plane defined and the element tangent plane are coplanar. In this case, this could pose problems to the Marc solver and should be corrected. For cylindrical systems, the plane used to intersect the element tangent plane is the r-z plane. Thus there are an infinite number of possible planes in the theta direction. The plane used for a particular element is determined by the radial vector emanating from the coordinate system’s zaxis to the centroid of the element and the z-axis. Display of the 1st preferred material direction is a single vector at the centroid of the element. A warning message is issued if the plane defined and the element tangent plane are coplanar. In this case, this could pose problems to the Marc solver and should be corrected. For 3D elements, the 3D ANISO option is used and the x and y axes of the selected coordinate system are written as the vectors in the ORIENTATION option with respect to the global system. The x, y, and z-axes define the 1st, 2nd, and 3rd preferred material directions. If an Orientation Angle is supplied, these vectors are rotated by this amount about the z-axis and written as such to the ORIENTATION option. For cylindrical systems the r, theta, z-axes are the 1st, 2nd, and 3rd preferred directions and again are rotated about z-axis if an Orientation Angle is supplied and written as such to the ORIENTATION option in the global system for each element. Display of the three preferred material directions is a triad at the centroid of the element with color coding and labels of the respective directions. Use the Element Properties application Show | Orientation Angle/System to visualize the preferred directions in Patran. For 2D elements, the 1st preferred direction is displayed at the centroid of the element or at the corners of the associated geometry. The 2nd preferred direction is in the plane of the element at 90 degrees to the 1st preferred direction but is not plotted. The 3rd preferred direction is normal to the element tangent plane and also is not plotted. For 3D elements the complete triad is plotted. The 1st, 2nd, and 3rd preferred directions are plotted as magenta, cyan, red, respectfully. See Volume C of the Marc documentation for more detailed information on the ORIENTATION option.

Elements in Coupled Analysis Specifying element property data for Coupled analysis is identical to Structural analysis. In fact, coupled elements are structural elements in Marc but internally use the corresponding thermal element for the heat transfer portion of the analysis. There is only one exception to this and that is when you want elements to only display thermal properties and act structurally rigid. All coupled elements have a

Main Index

Chapter 2: Building A Model 157 Element Properties

property word to force them to be structurally rigid. If this property word is left blank, structural element will be used. If set to “rigid,” the thermal element will be used and will act structurally rigid. The table below indicates the Marc structural element (jsolid) and its corresponding thermal equivalent (jheat). A minus one (-1) indicates that the element is already a thermal element. A zero (0) indicates that the element does not have an equivalent thermal element and the coupled analysis will stop if used in a Coupled analysis.

Main Index

jsolid/jheat

jsolid/jheat jsolid/jheat jsolid/jheat jsolid/jheat

jsolid/jheat

jsolid/jheat

1

88

27

41

53

69

79 100

105

-1

131

-1

157 135

2

38

28

42

54

69

80

39

106

-1

132

-1

158 37

3

39

29

41

55

70

81

39

107 105

133

-1

159 85

4

0

30

44

56

69

82

40

108 106

134 135

160 39

5

99

31

0

57

71

83

40

109

-1

135

161 39

6

37

32

41

58

69

84

43

110

-1

136 137

162 40

7

43

33

38

59

70

85

-1

111

-1

137

-1

163 43

8

0

34

41

60

69

86

-1

112

-1

138

50

164 135

9

36

35

44

61

71

87

-1

113

-1

139

85

165 0

-1

10

40

36

-1

62

0

88

-1

114 121

140

85

166 0

11

39

37

-1

63

0

89

87

115 121

141

-1

167 0

12

-1

38

-1

64

65

90

0

116 122

142

0

168 0

13

99

39

-1

65

-1

91 101

117 123

143

0

169 0

14

99

40

-1

66

42

92 102

118 121

144

0

170 0

15

88

41

-1

67

42

93 103

119 122

145

0

171 0

16

99

42

-1

68

0

94 104

120 123

146

0

172 0

17

0

43

-1

69

-1

95

0

121

-1

147

0

173 0

18

39

44

-1

70

-1

96

0

122

-1

148

0

174 0

19

39

45

65

71

-1

97

0

123

-1

149

175

175 149

20

40

46

0

72

85

98

36

124 131

150

176

176 150

21

44

47

0

73

0

99

-1

125 131

151

177

177 151

22

85

48

0

74

0

100

-1

126 132

152

178

178 152

23

0

49

50

75

85

101

-1

127 133

153

179

179 153

24

0

50

-1

76 100

102

-1

128 131

154

180

180 154

25

99

51

0

77 100

103

-1

129 132

155

37

26

41

52

99

78 100

104

-1

130 133

156

38

158 Marc Preference Guide Element Properties

Rebar Definition Tool For the Marc Preference, a special application for creation of 2D layered rebar is available under the Rebar Definition tool in the Tools pulldown menu. Discrete rebar models and general 3d layered rebar models are not supported. Rebar is actually an element property definition for the Marc Preference, however this tool is used to automate the creation of rebar layers and embed them into existing element meshes. This tool allows you to: • Create, modify, delete and visualize Rebar data definitions. • Support multiple rebar definitions, both isoparametric and skew type geometry. See Figure 2-1. • Support rebar membrane elements in 2D solid (plane strain and axisymmetric) elements. • Create a customized mesh and automatically assign rebar properties to these elements.

Note:

The Rebar Definition tool supports automatic generation of rebar elements and properties for 2D solid elements only. For rebar embedded into 3D solid elements, you must manually create the elements (mesh) and assign properties in the Element Properties application using 2D Rebar Membrane definition. You can also manually create 1D Rebar Membrane elements without using this tool but this is less convenient.

The most common use of this tool is in tire analysis, specifically where an axisymmetric model of a tire is created with multiple rebar layers. The axisymmetric rebar membrane elements are created across the existing mesh of the tire model using this tool. The axisymmetric analysis is run and then full 3D analysis performed by using Marc’s AXITO3D capability. The axisymmetric model is swept into full 3D including the rebar elements, which are then assigned 2D rebar membrane element properties for a full 3D analysis. This procedure is explained in Pre State Options.

Main Index

Chapter 2: Building A Model 159 Element Properties

Figure 2-1

Rebar layer definitions for 2D solid elements with a) SKEW and b) ISOMPARAMETIC type geometry.

The tool is quite simple to use as explained here. There are four basic commands: Create, Modify, Delete, and Show.

Main Index

160 Marc Preference Guide Element Properties

When a rebar layer is created it does a number of things: 1. First elements are created along the length of the curve. These elements are created such that nodes are placed at locations where the curve intersects element edges of the existing 2D mesh. You can think of the Rebar Definition tool as a specialized mesher. 2. A group with these nodes and elements by the same name as the rebar layer is created.

Main Index

Chapter 2: Building A Model 161 Element Properties

3. The elements for the rebar layer are assigned 1D rebar membrane properties. The Type and Option in the Element Properties application are determined by the continuum element types through which the rebar passes. This requires that the continuum element have properties assigned them before the rebar evaluation otherwise an error is issued. The list of continuum elements through with the layer passes plus the associated properties become part of the property set. The best way to illustrate this is through an example. Below is a 3x3 mesh with two rebar layers passing through it.

The rebar layers must be evaluated and nodes created at all the intersecting element edge locations shown by dots. Elements must then be created by connecting the dots. These elements must then have properties assigned to them and stored as new element properties by the same name as the rebar layer(s). You can think of the evaluation as a mesher and property assignment all in the same operation. Caution:

If you delete a rebar definition, the elements, property, and group that were created are still maintained (you can delete them manually if necessary). You can delete the elements and properties, but leave the rebar definition. If you try to recreate or modify an existing rebar definition it will recreate or modify the existing elements, property, and group.

The Rebar Definition tool is used to create layered rebar by defining a data set for a Curve list, material, cross-sectional area and other properties. After creation of the rebar definitions, you may proceed to the Analysis application and under Job Parameters you select the associated rebar for translation. See Job Parameters. When a user submits a job for analysis, only the rebar layers that are selected are translated Note:

That is, if a rebar layer exists but is not selected, it will not be translated. However if a rebar property is defined but has no corresponding rebar layer as defined in the Rebar Definition tool, it will still be translated.

The preferred method in Marc is to use rebar membrane elements 147, 148, 165-170. These elements do not occupy the same space as the continuum elements as is necessary with other types of Marc rebar elements, but must be inserted into the element using the INSERT option. They support the skew type of

Main Index

162 Marc Preference Guide Element Properties

definition because they are elements with one dimension less than their continuum counterparts. This means that a bar represents a layer across a 2D solid continuum element and a quad represents a plane across a 3D element, thus they can cross adjacent edges. A list of “membrane” rebar elements is listed here with their corresponding continuum element types .

Element

Description

Corresponding Elements

147

4-Node 3D Rebar Membrane

18 or 7, 84, 117

148

8-Node 3D Rebar Membrane

30 or 21, 35, 57

165

2-Node Plane Strain Rebar Membrane

11, 80, 115, 118

166

2-Node Axisymm Rebar Membrane

10, 82, 95, 116, 119

167

2-Node Axisymm Rebar Membr w/ twist

20, 83

168

3-Node Plane Strain Rebar Membrane

27, 29, 32, 34, 54, 56, 58, 60

169

3-Node Axisymm Rebar Membrane

28, 33, 55, 59, 96

170

3-Node Axisymm Rebar Membr w/ twist

66, 67

Note:

Main Index

These are the only rebar elements supported in the Marc Preference.

Chapter 2: Building A Model 163 Element Properties

For 3D applications where rebar membrane elements are inserted into Hex elements (or possibly where rebar membrane elements are overlaid on top of standard membrane elements, the Rebar Definition tool is not used. The user must manually create the elements or sweep them such as in a AXITO3D application and then assign rebar element properties to them. As part of the rebar element property definition, the host elements are specified. In actuality, the plane strain and axisymmetric cases can also be manually defined, but this is more difficult to mesh and visualize the rebar layers as the Rebar Definition tool does this for you. For a general 3D problem, the rebar membrane properties can vary on all four edges of the Hex elements in which they pass. For a AXITO3D problem, the property definitions will remain exactly the same as

Main Index

164 Marc Preference Guide Element Properties

for the axisymmetric case. They may vary on two of the edges but will not on the other two. In this case the c1 direction varies only. For a general case, a parametrically varying spatial field where c1 and c2 vary could be supplied.

Main Index

Chapter 2: Building A Model 165 Load Cases

Load Cases Load Cases in Patran are used to group loads, boundary conditions and contact definitions together. A load case is selected when preparing an analysis and is associated to a Load Step. See Load Step Creation. The operation of the Load Cases application is described in Load Cases Application (Ch. 5) in the Patran Reference Manual.

Main Index

166 Marc Preference Guide Load Cases

All loads and boundary conditions are placed into the active load case. You may change the active load case in the Loads and Boundary Conditions application directly on the main form before creating any loads or boundary conditions. If loads are placed in the wrong load case, you will have to enter this application and change their assignments. The Load Cases application also has some usefulness with its ability to scale entire load cases and individual LBCs assigned to a load case. There are three ways to assign a scale factor to an LBC: 1. When defining the LBC itself in the Loads and BCs application. This affects the LBC itself. 2. When defining a load case, all LBCs associated to a load case can be scaled by this scale factor defined on the main form. This does not affect the LBCs at all. The LBCs are only scaled for this load case. Other load cases can have other scale factors. 3. Within an individual load case, a single LBC can be scaled. Again this does not affect the LBC itself, but is only done for the selected LBC in that load case only.

As an example of how this is useful, suppose you have an analysis where a rigid body pushes against another body in the x-direction for 1 second. In the next second it reverses directions for 1 second. This can be accomplished with one rigid body contact LBC defining the motion in the x-direction. Then two load cases are defined with exactly the same set of LBCs in them including the contact. In the second load case, the individual rigid body contact LBC can be scaled by zero (0) for position controlled or minus one (-1) for velocity controlled motion to simulate the reversal of the rigid body. This is convenient rather than defining a time varying field to define this simple motion. Each load case must then be associated to a Load Step. Load Steps are simply supersets of load cases. See Load Step Creation.

Main Index

Chapter 2: Building A Model 167 Fields - Tables

Fields - Tables The Fields application is used to store tabular data that may be applied or associated with material or element properties, or loads and boundary conditions. The actual operation of the Fields application is described in Fields Application (Ch. 6) in the Patran Reference Manual. A brief description is supplied here as it pertains to the Marc Preference.

There are three basic types of fields or tables which can be used to define properties and values: • Material Fields - used primarily to define how a given material property varies with strain, strain

rate, time, frequency, or temperature. • Spatial Fields - used primarily to define how element properties vary over a surface, such as

thickness, or the length of a beam, such as cross-sectional area. Also used to define how loads vary with physical location. • Non-Spatial Fields - used primarily to define how loads and boundary conditions vary with time

or frequency.

Main Index

168 Marc Preference Guide Fields - Tables

Fields Overview Material property tabular data is entered with the Object set to Material Property. See Material Fields.

Main Index

Chapter 2: Building A Model 169 Fields - Tables

Time and frequency varying information is entered with the Object set to Non-Spatial.

Spatially varying information is entered with the Object set to Spatial such as variation of thickness over a plate or of the load versus distance.

Main Index

170 Marc Preference Guide Fields - Tables

Material Fields Some material properties can reference tabular data fields. The following is a brief explanation of what the Marc Preference does with these fields and how they get translated into the input file. This discussion for 2D and 3D data fields pertains to Marc version 2001 or earlier as these versions are incapable of dealing with fully populated 2D and 3D material fields through the standard input. For versions beyond 2001, fully populated data 1D, 2D, and 3D fields are translated verbatim to the input file using the TABLE option, thus obsoleting the following options: TEMPERATURE EFFECTS, ORTHO TEMP, STRAIN RATE, WORK HARD.

Main Index

Chapter 2: Building A Model 171 Fields - Tables

1D Fields This is the simplest case where only a one dimensional field has been referenced. The Marc input file will simply contains the proper option of x versus y values: Plastic Strain Fields

A referenced tabular field of plastic strain versus stress will create the WORK HARD option as such

WORK HARD, DATA # of points, 0, MATID s1, 0.0 s2, e2 s3, e3 s4, e4<- data repeated <# of points> times etc.

Note:

The stress value at zero plastic strain is entered as the yield stress in the ISOTROPIC, ORTHOTROPIC and ANISOTROPIC options.

Note:

The first plastic strain value must be zero in which case the stress-strain curve is assumed to be true stress vs true strain (natural log of the plastic strain). If it is not zero, then it is assumed that engineering stress/strain has been entered and will be converted to true stress/strain as required by the solver.

Temperature Fields

A referenced tabular field of temperature versus a material property value such as Yield Stress, Young’s Modulus or Poison’s Ratio will create the TEMPERATURE EFFECTS or ORTHO TEMP options as such: TEMPERATURE EFFECTS or ORTHO TEMP, DATA #1, #2, #3, #4, #5, #6, #7 s1, T1 s2, T2 s3, T3 s4, T4<- data repeated #1 times etc. E1, T1

Main Index

172 Marc Preference Guide Fields - Tables

E2, T2<- data repeated #2 times etc. etc.<- data repeated for each temperature dependent property

Note:

A Reference Temperature must be indicated on the Elastic constitutive model. The temperature curve at this temperature will be the reference temperature curve for writing strain hardening data on the WORK HARD option.

Strain Rate Fields

A referenced tabular field of yield stress versus strain rate will create the STRAIN RATE option as such STRAIN RATE, DATA # of points, mat ID s1, 0.0 s2, er2<- data repeated (# of points) times etc.

Note:

The first strain rate value must be zero.

Time/Frequency Fields

These work in a very similar way and create either VISCELMOON, VISCELOGDEN, VISCELPROP, CREEP or PHI-COEFICIENTS options. 2D Fields There are three scenarios for 2D material fields. Temperature - Plastic Strain Fields

A field of this nature indicates that both WORK HARD and TEMPERATURE EFFECTS (or ORTHO TEMP) options are written. Marc 2000 (or earlier) is incapable of dealing with a fully populated 2D table. A 2D table of temperature and plastic strain versus yield stress indicates a different stress-strain curve for each different temperature referenced as shown in the graph.

Main Index

Chapter 2: Building A Model 173 Fields - Tables

The Patran tabular field might look like this (x103):

T ep

0.0

0.01

0.1

1.0

0

30

33

35

40

100

29

31

32

33

200

27

28.5

29

30

500

20

21

22

25

But only the values in red (top row) are written to the WORK HARD option as the reference temperature curve, T1=0. WORK HARD, DATA 4, 30000.,0.0 33000.,0.01 35000.,0.1 40000.,1.0 Note:

Main Index

The yield stress at zero plastic strain is also written to the ISOTROPIC, ORTHOTROPIC, or ANISOTROPIC option.

174 Marc Preference Guide Fields - Tables

Only the values in blue (first column) are written to the TEMPERATURE EFFECTS (ORTHO TEMP) option to define the yield stress as a function of temperature. For temperature dependent hardening, what is written is the variation of slope with temperature divided by the slope of the reference curve (at T1=0 in this case) in the first region, i.e., between plastic strain of zero and 0.01: TEMPERATURE EFFECTS, DATA 4, 0, 0, 0, 0, 4, 1 30000.,0. 29000.,100. 27000.,200. 20000.,500. 1.0 ,0. 0.6667,100. 0.5 ,200. 0.3333,500. Note:

The first four points on the TEMPERATURE EFFECTS option denote the yield stress as a function of temperature at zero plastic strain. The last four points denote the work hardening versus temperature as a ratio of the slope in the first region ( ε p Z 0, ε p Z 0.01 ) divided by the slope of the curve at the reference temperature: Slope at reference temperature: (33 - 30) / (0.01 - 0) = 300; 300/300 = 1.0 Slope at other points: (31 - 29) / 0.01 = 200; 200/300 = 0.6667 (28.5 - 27)/ 0.01= 150; 150/300 = 0.5 (21 - 20) / 0.01 = 100; 100/300=0.3333

Temperature - Strain Rate Fields

A field of this nature indicates that both STRAIN RATE and TEMPERATURE EFFECTS (or ORTHO TEMP) options are written. Marc 2000 (or earlier) is incapable of dealing with a fully populated 2D table. A 2D table of temperature and strain rate versus yield stress indicates a different stress/strain-rate curve for each different temperature referenced as shown in the graph.

Main Index

Chapter 2: Building A Model 175 Fields - Tables

The same table is used as in the previous example except strain is now strain rate (x103):

T er

0.0

0.1

0.5

1.0

0

30

33

35

40

100

29

31

32

33

200

27

28.5

29

30

500

20

21

22

25

Only the values in red are written to the STRAIN RATE option (which are the values from the reference temperature curve). STRAIN RATE, DATA 4,1 30000.,0.0 33000.,0.1 35000.,0.5 40000.,1.0

Main Index

176 Marc Preference Guide Fields - Tables

And only the values in blue are written to the TEMPERATURE EFFECTS (ORTHO TEMP) option. Again, the yield stress of the reference curve at zero strain rate is written to the ISOTROPIC, ORTHOTROPIC, or ANISOTROPIC options. TEMPERATURE EFFECTS, DATA 4,0,0,0,0,0,1 30000.,0.0. 29000.,100. 27000.,200. 20000.,500. Note:

The first four points on the TEMPERATURE EFFECTS option denote the yield stress change with temperature at zero strain rate.

Plastic Strain - Strain Rate Fields

A field of this nature indicates that both STRAIN RATE and WORK HARD options are written. Marc 2000 (or earlier) is incapable of dealing with a fully populated 2D table. A 2D table of strain and strain rate versus yield stress indicates a different stress/strain-rate curve for each different strain referenced as shown in the graph. The same table is used as in the first 2D example except temperature is now strain rate (x103):

Main Index

Chapter 2: Building A Model 177 Fields - Tables

ep er

0.0

0.1

0.5

1.0

0.0

30

33

35

40

0.01

29

31

32

33

0.1

27

28.5

29

30

1.0

20

21

22

25

But only the values in red (at zero strain) can be written to the STRAIN RATE option and only the values in blue (at zero strain rate) can be written to the WORK HARD option: STRAIN RATE, DATA 6, 1 30000.,0.0 33000.,0.1 35000.,0.5 40000.,1.0 WORK HARD, DATA 4, 0, 1 30000.,0.0 29000.,0.01 27000.,0.1 20000.,1.0 3D Fields There is only one scenario for 3D fields. Temperature - Plastic Strain - Strain Rate Fields

A field of this nature indicates that WORK HARD, STRAIN RATE and TEMPERATURE EFFECTS (or ORTHO TEMP) options are written. Marc 2000 (or earlier) is incapable of dealing with a fully populated 3D table. A 3D table of temperature, plastic strain, and strain rate versus yield stress indicates a different stress-strain curve for each different temperature referenced as shown in the graph plus another dimension as the strain rate changes. The Patran tabular field might look like this (a combination of the above three 2D cases): er=0.0

T ep

er=0.1

Main Index

0.0

0.01

0.1

1.0

0

30

33

35

40

100

29

31

-

-

200

27

28.5

-

-

500

20

21

-

-

T

178 Marc Preference Guide Fields - Tables

ep

er=0.5

0.0

0.01

0.1

1.0

0

33

-

-

-

100

-

-

-

-

200

-

-

-

-

500

-

-

-

-

0.0

0.01

0.1

1.0

0

35

-

-

-

100

-

-

-

-

200

-

-

-

-

500

-

-

-

-

0.0

0.01

0.1

1.0

0

40

-

-

-

100

-

-

-

-

200

-

-

-

-

500

-

-

-

-

T ep

er=1.0

T ep

Values not written to the input file have been intentionally left out of the above tables to illustrate what is actually written. Only the values in red (first row of first table) are written to the WORK HARD option. See the explanation under 2D Fields. WORK HARD, DATA 4, 30000.,0.0 33000.,0.01 35000.,0.1 40000.,1.0 Only the values in blue (first column of first table) are written to the TEMPERATURE EFFECTS (ORTHO TEMP) option for yield stress versus temperature and the change in slope for work hardening versus temperature. Again, this is explained in 2D Fields. TEMPERATURE EFFECTS, DATA 4, 0, 0, 0, 0, 4, 1 30000.,0. 29000.,100. 27000.,200. 20000.,500. 1.0 ,0. 0.6667,100. 0.5 ,200. 0.3333,500.

Main Index

Chapter 2: Building A Model 179 Fields - Tables

Only the values in green (values of strain rate at zero strain at the reference temperature) are written to the STRAIN RATE option. STRAIN RATE, DATA 4, 1 30000.,0.0 33000.,0.1 35000.,0.5 40000.,1.0

Spatial Fields Some element properties and loading conditions can reference tabular data fields or fields defined by PCL functions. The following is a brief explanation of what the Marc Preference does with these fields and how they get translated into the input file. codeindent10: Suppose you want to define a property, such as shell thickness, to vary over the surface of a 1x1 square flat plate such that at (0,0) thickness is 1.0 and (1,1), thickness is 2.0. Thicknesses in between these coordinates will be linearly interpolated. You could define a table such as: X Y 0.0 1.0

0.0 0.0 1.5

1.0 1.5 2.0

Or you could define a PCL function to accomplish the same thing such as: 0.5*(‘X+1) + 0.5*(‘Y+1) The values at each element centroid or nodal point, depending on what is requested, will be evaluated and written accordingly to the Marc input file. The above example could be used to also vary the pressure across the plate. A pressure loading referencing this spatial field could be applied with an appropriate scale factor to scale it to the proper loading value. Or you could create a new table or PCL function with the scaling already accommodated.

Non-Spatial Fields These fields or tables are typically used with loading conditions that need to vary over time or frequency. Only tabular fields are supported with one or two active independent variables, those being either time or frequency and velocity or displacement. The following is a brief explanation of what the Marc Preference does with these fields and how they get translated into the input file. As a brief explanation, suppose you wish to define a load that ramps from zero to one and then back down to zero over one second. A simple table as shown below can be created:

Main Index

180 Marc Preference Guide Fields - Tables

Time

Value

0.0

0.0

0.5

1.0

1.0

0.0

This could represent a position controlled rigid body that moves one unit towards the deformable contact body in the first half second and then back to its original position in the second half second. Or it could represent a load that is scaled to its full value in the first half second and then taken back down to zero in the second half second. What is written to the Marc depends on how the load stepping is set up under the Analysis application. If only one load step is created, the Marc input file might look something like this for motion control: <parameter section> END <model section> CONTACT END OPTION MOTION CHANGE <position set to one unit> TIME STEP 0.5 CONTINUE MOTION CHANGE <position set back to zero> TIME STEP 0.5 CONTINUE

or like this for a point loading: <parameter section> END <model section> POINT LOAD END OPTION POINT LOAD TIME STEP 0.5 CONTINUE POINT LOAD TIME STEP 0.5 CONTINUE

The job could also be broken up into two load steps within the Analysis application where the first load step covers the first half second and the second step covers the last half second. In this way, you can control the load incrementation and other control parameters that may need to be different for the first half second relative to the second half second. For example: <parameter section> END <model section> POINT LOAD END OPTION AUTO LOAD 18 POINT LOAD TIME STEP 0.5

Main Index

Chapter 2: Building A Model 181 Fields - Tables

CONTINUE AUTO LOAD 24 POINT LOAD TIME STEP 0.5 CONTINUE

An important point with non-spatial fields is for motion control of rigid bodies. When defining motion that varies with time or that split between two or more Load Steps, it is advantageous and sometime necessary to define the motion via a non-spatial field of motion (either velocity or displacement) versus time. This is done identically to the discussion above. However, with contact if you define a 1D field (one independent variable), the motion of all the components of the rigid body are defined by this field. You have no control over each component individually, including the angular position or velocity. To control each component separately, you must define a 2D field of motion (velocity or position) versus time. In this case you select both time and displacement or velocity as the independent variables. You must then fill out a tabular two dimensional field. As an example let us say that a rigid body motion is to move in the y-direction for the first second and then in the x-direction for the 2nd second. You would define a field like this:

x-comp

y-comp

z-comp

angular comp.

1.0

2.0

3.0

4.0

0.0

0.0

0.0

0.0

0.0

1.0

1.0

0.0

0.0

0.0

2.0

0.0

1.0

0.0

0.0

Time

Main Index

Note:

All four components must be defined. The values (1.0, 2.0, 3.0, 4.0) above each component column are arbitrary but must be in ascending value to define the field.

Note:

Also, whenever possible, for Marc version 2003 and beyond, if a TABLE option can be written to define a field it will!

182 Marc Preference Guide Fields - Tables

Main Index

Chapter 3: Running an Analysis Marc Preference Guide

3

Main Index

Running an Analysis



Overview



Job Parameters



Load Step Creation



Load Step Selection



Domain Decomposition



Resolving Convergence Problems

182 184 231 332 334 341

182 Marc Preference Guide Overview

Overview Once the model is created, the analysis may be set up and submitted. This is the subject of this Chapter, which also details Marc keywords written to the Marc input file. A list of all Marc supported keywords are listed in Supported Keywords. Only aspects relating to the creation of these keyword via Patran’s (or MSC.AFEA’s) graphical user interface are explained in this Chapter. The Analysis application appears when the Analysis toggle, located on the main form, is chosen. This form is used to request an analysis of the model with the Marc finite element program. The Analysis application is used to prepare an Marc analysis, and is introduced on the next page, followed by detailed descriptions of each subordinate form. For further information on the Analysis application, see The Analysis Form (p. 8) in the MSC.Patran Reference Manual.

The Analysis application is also used to: 1. Read the contents of a Marc input file or results file into the database. See Data Import (Action: Read Input File), 20

2. Import or attach results data. See Results Access (Action: Read Results), 20. 3. Monitor the progress of an analysis. See Monitor a Job (Action: Monitor), 22. 4. Delete a job or results file attachment. See Job or Result Deletion (Action: Delete), 21. 5. Abort a running job. See Aborting a Job (Action: Abort), 25. 6. Run a demonstration problem. See Example Problems (Action: Run Demo), 25. This chapter deals only with submitting an analysis (Action: Analyze). This form appears when the Analysis application toggle is selected on the main menu. When the Action is set to Analyze, an Marc analysis may be prepared and submitted. (Other Actions on this form are discussed elsewhere. See Overview.) The operation of this form is in a general, top-down manner. Start at the top of the form, setting the appropriate widgets and forms, and press Apply when ready to submit the analysis.

Main Index

Chapter 3: Running an Analysis 183 Overview

Main Index

184 Marc Preference Guide Job Parameters

Job Parameters This subordinate form appears when the Job Parameters button is selected on the Analysis application form. Parameters on this form and its subordinate forms control non-solution specific parameters that generally are placed in the Parameter or Model Definition sections of the Marc input file.

The widgets in the above form are explained in the table below.

Main Index

Chapter 3: Running an Analysis 185 Job Parameters

Translation Parameter

Main Index

Description

Marc Version

This can be set to 2007 (default), 2005, 2003 , 2001, 2000, or K7. Some of the forms and settings key off of this setting. This only controls what forms and values are presented to you when setting up an analysis and what is written to the input file. It does not directly control what version of Marc is actually run. This is done via the P3_Trans.ini file on NT or the site_setup file on UNIX. See Analysis Submission Configuration. If 2005, a VERSION,11 parameter is written. If 2003, a VERSION,10 parameter is written. This parameter indicates version specific option formats.

Output File Format

Can be K2, K3, K4, K5, K6, K7, 2000, 2001, 2003 2005, or 2007. The default the same as the Marc Version. This parameter generally places either a 1, 3, 4, 5, 6, 7, 9, 10, 11 or 12, respectively, in the 11th field of the 2nd data block of the POST option. If the Marc Version is the same, then a zero (0) is placed in this field indicating that a POST file of the latest format be written. You cannot set this to a higher version than the Marc Version is set at.

Results File Type

Can be Binary (default), Text, Both, or None. This parameter places either a 0, 1, or 2, respectively, in the 4th field of the 2nd data block of the POST option. If none is selected, no POST option is written.

Assumed Strain

If ON, (default is OFF), places the ASSUMED parameter into the input file. This will force all elements that can deal with assumed strain to use this formulation. This improves the bending behavior of elements 3, 7, and 11. If you wish to control this formulation option for each individual element property set, you must turn this setting OFF.

Constant Dilatation

If ON, (default is ON for Structural/Coupled, OFF for Thermal), places the CONSTANT parameter into the input file. This will force all elements that can deal with constant dilatation (for nearly incompressible analysis) to use this formulation. This affects element types 7, 10, 11, 19, and 20 only and recommended for elastic-plastic and creep analysis. If you wish for each individual element property set to define this separately, you must turn this setting OFF.

Element Centroid Method

If ON, (default is OFF), places the CENTROID parameter into the input file. It is not recommended with non-linear analysis as results are stored at the centroid of each element only and thus it reduces accuracy.

Lumped Matrix

If ON, (default is OFF), places the LUMP parameter into the input file. This is only used for dynamics (lumped mass matrix) or heat transfer (lumped specific heat matrix) and will be ignored for any other analysis type.

186 Marc Preference Guide Job Parameters

Translation Parameter

Description

Heat Generation Conversion For Coupled analysis only, this factor can be provided as a conversion Factor factor between inelastic mechanical energy and heat transfer flux. Default is 1.0. Extended Format

If this is ON, the Marc input file is created in extended format, thus doubling the field width of each entry in the input file. The EXTENDED parameter is placed in the input file. This is ON by default. If Free Field is also ON, the actual field length is only extended when necessary. You cannot turn this OFF if Free Format is ON.

Free Format

If this is set, free field input formats will be used when creating the Marc input file. Fields are separated by commas in the input file but still placed within the normal fixed field width. This is ON by default. You cannot have Extended Format OFF when Free Format is ON.

# of Significant Digits

Defines the number of significant digits to be used when creating the Marc input file. This can be set to any value in the range of three through eight depending on whether extended format is requested or not.

Use Tables:

Available only when Marc Version is set to 2003 or greater. When this toggle is ON, the TABLE option will be used to write data defined by fields such as time varying loads or temperature varying material properties. Anything that can be described via the TABLE option will be if this option is ON. You can control Materials, Loads and BCs, and Contact tables separately. Additional toggles apprear when this toggle is ON to do so.

Materials LBCs Contact

Loads on Geometry

If ON, (default is OFF), uses POINTS, CURVES, SURFACES, ATTACH NODES, ATTACH ELEMENT, ATTACH EDGE, and ATTACH FACE options in conjuction with TABLES (Use Tables must be ON also). This associates loads and boundary conditions to geomtric entities directly in the input file using the above options. This is most useful when used in conjunction with adaptive meshing where the mesh can change but the loads remain consistent and not dependent on a node or element number that changes due to remeshing. See the discussion below in Loads on Geometry, 186. Valid only for Marc Version 2003 or greater. Note:

This is not fully supported at this time.

Loads on Geometry The following geometric entities can be written to the Marc input file into the Model Definition section in Marc Version 2003 and beyond.

Main Index

Chapter 3: Running an Analysis 187 Job Parameters

1. POINTS - this is a simple definition: Data Block 1: POINTS Data Block 2: # of points defined Data Block 3: Point ID, X-coord, Y-coord, Z-coord For POINTS to be properly used in an input file, FEM nodes must be attached to them via the ATTACH NODE option which is already supported for adaptive meshing (except in that case they are attached to SURFACEs) ATTACH NODE is used to attach nodes to POINTS in the case of POINT LOAD, POINT FLUX, FIXED DISP, FIXED TEMP and any other nodal based LBC. The typical scenario for this is that one of these LBC types has an application region of Patran points. These points are associated to Patran nodes. Thus the POINTS option is used to write the points to the input file. The ATTACH NODE option is used to associate the associated Patran nodes to the POINTS option. The LBC type is written to the input file with the geometric ids in the blocks requesting the geometry type and IDs. 2. CURVES - this is a bit more complicated: Data Block 1: CURVES Data Block 2: # of curves defined Data Block 3: Curve ID, curve type (always 4 for 2-D NURB curve) Data Block 4-7: NURB definition For CURVES to be properly used in an input deck, FEM nodes must be attached to them via the ATTACH NODE option or FEM element edges must be associated using the ATTACH EDGE option. This is dependent on the LBC type being defined. ATTACH NODE is used to attach nodes to CURVES in the case of POINT LOAD, POINT FLUX, FIXED DISP, FIXED TEMP and any other nodal based LBC. ATTACH EDGE is used to attach element edges to CURVES in the case of distributed loads or films or other element based LBCs. The typical scenario for this is that one of these LBC types has an application region of Patran curves (edges). These curves are associated to Patran nodes or element edges depending on whether the LBC is nodal or element based. Thus the CURVES option is used to write the Patran curves to the input deck. The ATTACH NODE option is used to associate the associated Patran nodes to the CURVES in the case of nodal LBCs. The ATTACH EDGE option is used to associate the associated Patran element edges to the CURVES in the case of element based LBCs. The LBC type is written to the input deck with the geometric ids in the blocks requesting the geometry type and IDs. 3. SURFACES - this is basically same as CURVES: Data Block 1: SURFACES Data Block 2: # of surfaces defined Data Block 3: Surface ID, surface type (always 4 for 2-D NURB surface) Data Block 4-7: NURB definition

Main Index

188 Marc Preference Guide Job Parameters

For SURFACES to be properly used in an input deck, FEM nodes must be attached to them via the ATTACH NODE option or FEM element faces must be associated using the ATTACH FACE option. This is dependent on the LBC type being defined. ATTACH NODE is used to attach nodes to SURFACES in the case of POINT LOAD, POINT FLUX, FIXED DISP, FIXED TEMP and any other nodal based LBC. ATTACH FACE is used to attach shell elements or solid element faces to SURFACES in the case of distributed loads or films or other element based LBCs. The typical scenario for this is that one of these LBC types has an application region of Patran surfaces (or faces). These surfaces are associated to Patran nodes or shell elements or solid element faces depending on whether the LBC is nodal or element based. Thus the SURFACES option is used to write the Patran surfaces to the input deck. The ATTACH NODE option is used to associate the associated Patran nodes to the SURFACES in the case of nodal LBCs. The ATTACH FACE option is used to associate the associated Patran shell elements or solid element faces to the SURFACES inthe case of element based LBCs. The LBC type is written to the input deck with the geometric ids in the blocks requesting the geometry type and IDs. The actual option that is written is dependent on the Patran goemetric entity in the application region. In general, the same type of geometry is written to the Marc input deck. The edge and face IDs necessary to define and associate FEM with geometry are listed in Vol C under FACE IDS. The following table shows the applicable load and boundary condition types that can be associated with geometric entities written to the Marc input deck. It also shows the relation between the Patran geometric application region and what is written to the Marc input deck.

Main Index

Chapter 3: Running an Analysis 189 Job Parameters

:

LBC Type

Patran Application Region

FIXED DISP Nodes FIXED TEMP POINT LOADS Points POINT FLUX INITIAL DISP Curves and/or Edges INITIAL VEL INITIAL TEMP Surfaces and/or Faces

DIST LOADS DIST FLUXES FILMS

Required Marc Options

Geometry Type ID

None

2: Nodes ids

POINTS ATTACH NODES

6: Point ids

CURVES ATTACH NODES

5: Curve ids

SURFACES ATTACH NODES

4: Surface Ids

Solids

Not yet fully defined ATTACH ELEMENT

3: Volume ids

Elements

None

1: Element ids

Curves and/or Edges

CURVES ATTACH EDGE

5: Curve ids

Surfaces and/or Faces

SURFACES ATTACH FACE

4: Surface ids

Solids

Not yet fully defined ATTACH ELEMENT

3: Volume ids

There can be different mixes and matches of geometry types defined for a single LBC. Marc Vol C , Program Input explains that this is handled in the 3rd data block of each LBC type above where the number of geometric types is specified. The 6th & 7th (or 7th & 8th) data blocks are then repeated for each type of geometry.

Solvers / Options The following form appears for selecting Solvers and other Options on the Job Parameters form. The table below explains each parameter for each solver or option. This places the SOLVER and OPTIMIZE option and the MPC-CHECK parameter into the input deck.

Main Index

190 Marc Preference Guide Job Parameters

Solver Parameter

Main Index

Description

Inconsistent MPCs

This option (available for Marc version 2005 or higher) can be set to Reorder (default), Continue or Stop. The order in which ties were applied previously to 2005 was fixed and determined in the order in which they were given in the input deck. For certain options such as CONTACT, INSERT, etc. Marc internally uses ties. With Reorder, Marc applies the constraints in a correct order by forcing an automatic renumbering of all tying equations. For previous behavior, set to Continue of Stop. If an MPC tying conflict occurs the program will continue with warnings, or stop with an error message depending on the setting.

Solver Type

Can be set to Direct Pro deck, Iterative Sparse, Direct Sparse, Hardware Sparse, Multifrontal Sparse (default) or External Sparse. These are the only Marc solvers supported. This places a 0, 2, 4, 6, 8 or 9 in the 1st field of the 2nd data block of the SOLVER option.

Non-Symmetric

Places a 1 in the 2nd field of the 2nd data block of the SOLVER option. This is only valid for Solver Type of Direct Prodeck or Multifrontal Sparse.

Non-Positive Definite

Places a 1 in the 3rd field of the 2nd data block of the SOLVER option. Valid for all Solver Type selections.

Memory

Specify the amount of work space in words. This can be left blank and the translator will automatically determine this based on model size. It is placed on the 2nd field of the SIZING parameter if supplied.

Bandwidth Optimization

Writes the OPTIMIZE option to the input deck. It is only available for the Direct Prodeck or Multifrontal Sparse solvers and uses the Sloan or Metis algorithms, respectively. This is entered on the second field of the 1st data block of the OPTIMIZE option as a 9 or 11, respectively. Other solvers have their own optimizer and use it by default.

Max. Num. Iterations

For Iterative Sparse solver only. Enters this maximum number of iterations in the 1st field of the 3rd data block of the SOLVER option. Default is 1000.

Chapter 3: Running an Analysis 191 Job Parameters

Solver Parameter

Description

Stress Analysis Tolerance

For Iterative Sparse solver only. Enters this floating point number in the 1st field of the 4th data block of the SOLVER option. Default is 0.001.

Preconditioner

For Iterative Sparse solver only. Enters a 3, 4, or 5 respectively for Diagonal, Scaled Diagonal, or Incomplete Cholesky (default) preconditioners into the 3rd field of the 3rd data block of the SOLVER option.

Use Previous Solution as Trial

For Iterative Sparse solver only. Enters a 1 if ON (OFF by default) into the 2nd field of the 3rd data block of the SOLVER option.

Out-of-Core Threshold For Hardware and Multifrontal Sparse solvers only. Enters this integer number in the 7th field of the 2nd data block of the SOLVER option. Default is 100. Represents the number of real*4 words in millions of words. Only for SGI computers running the IRIX operating system.

Contact Parameters This subordinate form appears when the Contact Parameters button is selected on the Job Parameters forms. If contact boundary conditions have been defined in the Loads/Boundary Conditions

Main Index

192 Marc Preference Guide Job Parameters

application, this form, together with its subordinate forms, may be used to define most general entries in the CONTACT option. If no contact has been defined, it is unnecessary to modify anything on this form.

Main Index

Chapter 3: Running an Analysis 193 Job Parameters

Contact Parameter Deformable-Deformable Method Optimize Constraint Equations

Description In Double-Sided method, for each contact body pair, nodes of both bodies will be checked for contact. In Single-Sided method, for each contact body pair, only nodes of the lower-numbered body will be checked for contact. Results are dependent upon the order in which contact bodies are defined. This enters a 1 in the 3rd field of the 4th data block. If Optimize Constraint Equations is ON, then a 2 is place in this field. This latter algorithm automatically optimizes the set of contact constraint equations based on the average stiffness of contact bodies, the element edge lengths, and the occurance of sharp corners for deformable, doubled-sided contact only.

Penetration Check

This controls contact penetration checking. sometimes referred to as the increment splitting option. Available options are: Per Increment, Per Iteration (default), Suppressed (Fixed), Suppressed (Adaptive. This enters a 0, 3, 1, or 2 in the 7th field of the 2nd data block, respectively. Per Increment means penetration is checked at the end of a load increment. Per Iteration means that penetration is checked at the end of every iteration within an increment. If penetration is detected, increments are split. Suppress is to suppress this feature for Fixed and Adaptive load stepping types.

Reduce Printout of Surface Definition

This controls reduction of printout of surface definition. This enters a 1 in the 11th field of the 2nd data block if ON.

Contact Detection This form controls general contact parameters for contact detection. All of these parameters affect the CONTACT option.

Main Index

194 Marc Preference Guide Job Parameters

Contact Parameter

Main Index

Description

Distance Tolerance

Distance below which a node is considered touching a body (error). Leave the box blank to have Marc calculate the tolerance. Distance Tolerance is entered in the 2nd field of the 3rd data block.

Bias on Distance Tolerance

Contact tolerance BIAS factor. The value should be within the range of zero to one. This is entered in the 6th field of the 3rd data block. Models with shell elements seem to be sensitive to this parameter. You may need to experiment with this value if you have shell element models that will not converge or penetration appears to occur. A Bias of zero means that the penetration is checked within 1/2 of the Distance Tolerance either side of the element. If during an increment, a node penetrates further than 1/2 of the Distance Tolerance, this may not be detected. Setting the Bias to 0.95 (default), means that 95% of the Distance Tolerance checking is within the element or on the penetrating side of the element.

Chapter 3: Running an Analysis 195 Job Parameters

Contact Parameter

Description

Suppress Bounding Box

Turn ON this button if you want to suppress bounding box checking. This might eliminate penetration, but slows down the solution.This enters a two(2) in field 8 of the 2nd data block for 3D contact only.

Check Layers

For contact bodies composed of shell elements, this option menu chooses the layers to be checked. Available options are: Top and Bottom, Top Only, Bottom Only. Check Layers and Ignore Thickness combination enters the appropriate flag in the 10th field of the 2nd data block.

Ignore Thickness

Turn this button ON to ignore shell thickness. Check Layers and Ignore Thickness combination enters the appropriate flag in the 10th field of the 2nd data block.

Activate Quadratic Contact

Turn this button ON to activate genuine quadratic contact, otherwise, midside nodes will not come into contact and are linearly tied to corner nodes. Activate Quadratic Contact enters a minus one(1) in the 14th field of the 2nd data block. This also affects the Separation Criterion on the next form. Only stress separation criterion is allowed if this is ON.

Activate 3D Beam-Beam Contact

Turn this button ON to activate 3D beam-beam contact. Activate 3D Beam-Beam Contact enters a one(1) in the 13th field of the 2nd data block.

Separation This form controls general contact parameters for contact separation. All of these parameters affect the CONTACT option.

Main Index

196 Marc Preference Guide Job Parameters

Contact Parameter

Main Index

Description

Maximum Separations

Maximum number of separations allowed in each increment. Maximum Separations is entered in the 6th field of the 2nd data block. Default is 9999.

Retain Value on NCYCLE

Turn ON this button if you do not want to reset NCYCLE to zero when separation occurs. This speeds up the solution, but might result in instabilities. You can not set this and Suppress Bounding Box simultaneously. Retain Value of NCYCLE enters a three(3) in field 8 of the 2nd data block.

Chapter 3: Running an Analysis 197 Job Parameters

Contact Parameter Increment / Chattering

Increment and Chattering enter the appropriate flag in the 9th field of the 2nd data block. This controls separation within an increment. When Chattering is Allowed, nodes are allowed to separate within an increment if the force/stress on the node is greater than the threshold (Force/Stress Value) in the Current increment (writes a zero to the field), unless Next increment is selected. In this case, if a node, which was in contact at the end of the previous increment, has a force/stress greater than the threshold, the node does not separate until the beginning of the Next increment (writes a one to the field). If Chattering is Suppressed, then if a new node comes into contact in the Current increment, it is not allowed to separate during this increment (writes a two to the field). If Chattering is Suppressed and Next increment is selected, then not only will new nodes coming into contact not be allowed to separate, but also nodes having a greater force/stress than the threshold at the end of the previous increment won’t be allowed to separate until the beginning of the Next increment (writes a three to the field).

Separation Criterion

Separation Criterion enters a zero (1) in the 12th field of the 2nd data block if separation is based on forces. Enters a 1, 2, 3, or 4 if Stresses based on the Derivaition and Relative / Absolute settings. If Activate Quadratic Contact from the Contact Detection form is set ON, only normal Stresses can be used as a separation criterion.

Force Value Stress Value

Force/Stress Value is placed in the 5th field of the 3rd data block. This is the force or stress threshold above which a node is allowed to separate.

Derivation

If Stresses are used as the Separation Criterion, then separation is based on either Relative or Absolute nodal stress, where a nodal stress is calculated as a force divided by an equivalent area (Force / Area) or determined by extrapolating and averaging integration point values (Extrapolation). If the contact normal stress on a node exceeds the threshold, the node separates. These settings determine the separation flag written to the 12th field of the 3rd data block. If Activate Quadratic Contact from the Contact Detection form is set ON, only the Extrapolation derivation can be used.

Relative / Absolute

Main Index

Description

198 Marc Preference Guide Job Parameters

Friction Parameters

Contact Parameter

Main Index

Description

Friction Type

Available options for friction Type are: None, Shear (for metal forming), Coulomb (for normal contact - default), Shear for Rolling, Coulomb for Rolling, Stick-Slip, Bilinear Coulomb, and Bilinear Shear. Type and Method: places 0, 1, 2, 3, 4, 5, 6, or 7in the 4th field of the 2nd data block depending on fiction type and places a 0 or 1 in the 5th field of the 2rd data block for friction based on nodal forces or nodal stresses respectively for Coulomb fiction. Stick-Slip is a Coulomb type friction.

Method

For Coulomb type of friction models (options 2, 4, and 5 above), there are 2 methods for computing friction: Nodal Stress (by default), Nodal Forces. Type and Method: places 0, 1, 2, 3, 4, or 5 in the 4th field of the 2nd data block depending on fiction type and places a 0 or 1 in the 5th field of the 2rd data block for friction based on nodal forces or nodal stresses respectively for Coulomb fiction.

Chapter 3: Running an Analysis 199 Job Parameters

Contact Parameter Relative Sliding Velocity Slip Threshold

Description Critical value for sliding velocity below which surfaces will be simulated as sticking. Relative Sliding Velocity is placed in the 1st field of the 3rd data block for all friction models except Stick-Slip. For the Bilinear methods, this databox label changes and is for entering the Slip Threshold, which by default is zero, flagging an automatic setting for this parameter.

Transition Region

Slip-to-Stick transition region. Transition Region is placed in the 1st field of the 3rd data block for Stick-Slip model.

Multiplier to Friction Coefficient

Friction coefficient multiplier. Multiplier to Friction Coefficient and Friction Force Tolerance are placed in the 7th and 8th field of the 3rd data block respectively for the Stick-Slip friction model.

Friction Force Tolerance

Friction Force Tolerance. Multiplier to Friction Coefficient and Friction Force Tolerance are placed in the 7th and 8th field of the 3rd data block respectively for the Stick-Slip friction model. This parameter is also used for the Bilinear methods.

Heat Generation Conversion For Coupled analysis only, this is the conversion factor between Factor energy due to friction and heat generated in a contact analysis. The default is 1.0.

Direct Text Input This widget is to facilitate the input of the Marc input data that cannot be created using the functionality available in the Marc Preference. All data input here will be appended to the Marc Parameter or Model Definition data sections. There is no error checking available for invalid input. Information in this form is saved and associated with the job.

Main Index

200 Marc Preference Guide Job Parameters

DTI Parameter Additional Parameter Input

Text in this area will be placed in the Parameters section of the input deck just before the END keyword.

Additional Model Definition Input

Text in this area will be placed in the Model Definition section of the input deck just before the END OPTION keyword.

Write at Beginning/End

This toggle specifies whether the text is written at the beginning of the section or at the end of the section. For Parameters this is written at the top of the input deck after any TITLE parameters or just before the END statement. For the Model Definition, this is written either just after the END statement or just before the END OPTION statement. End is default.

Parameters Section

These toggle between defining input for Parameters or Model Definition.

Model Definition Section

Main Index

Description

Clear

This clears the text in the text data box for the section that is selected.

Cancel

This closes the form without any changes saved.

Apply

This closes the form and saves the changes made to both sections.

Read From File

This will populate the text data box with text from the indicated deck. This brings up a typical deck browser to select the deck. Both the Parameter and Model Definition sections can be populated separately by reading a deck.

Chapter 3: Running an Analysis 201 Job Parameters

Note:

Direct Text Input, 330 (DTI) is also available in the History section of the Marc input deck when creating Load Steps. This feature is not available for MSC.AFEA.

Groups to Sets This functionality will convert any selected Patran group that contains nodes and/or elements into Marc element and node sets using the DEFINE option and place the SETNAME parameter in the Parameter section or the input deck.

Main Index

202 Marc Preference Guide Job Parameters

Groups/Sets Parameter Select Groups to Translated to Sets

Description Lists all groups available. Select all the groups you wish to translate in this list box and it will place them in the Groups Translated to Sets list box.

Groups Translated to Sets

Lists all groups that will be translated. Clicking on a group name in this list box will remove it.

Translate Group Members Into:

Either Node Sets or Element Sets (both OFF by default) will create the appropriate DEFINE option in the input deck. No error checking is done for duplicate element or node IDs between groups

OK

Closes the form and saves the information.

Cancel

Closes the form and does not save any changes.

Example: A group called “wing” with both elements and nodes will be written as: DEFINE, NODE, SET, wing_N list of nodes

Main Index

Chapter 3: Running an Analysis 203 Job Parameters

DEFINE, ELEMENT, SET, wing_E list of elements

The name of the set is the group name with the words _N or _E appended. Note:

In Marc the set names are limited to 12 characters. Group names must therefore be unique in their first 10 characters.

Restart Parameters This subordinate form appears when the Restart Parameters button is selected on the Translation Parameters form. This places a RESTART or RESTART LAST option in the input deck and invokes the Marc solver with the -r parameter on the run_marc script when submitting a restart job.

Note:

Main Index

For a restarted job, the CONNECTIVITY and COORDINATES and other Model Definition information is not written to the input deck, thus reducing the input deck size. Only the necessary information is written.

204 Marc Preference Guide Job Parameters

Parameter

Description

Restart Type

You can Write restart data, Read restart data and Read and Write restart data. The default is None for no restart data.

Create Continuous Results File

If when restarting a job, you wish the results form the previous run to be copied into the new POST deck, then turn this ON. This will place the RESTART or RESTART LAST options before the POST option in the input deck. Otherwise they are placed after the POST option which flags Marc not to copy the results to the new POST deck. If you turn this ON, you must have a restarname.t16 and/or restartname.t19 deck in your local directory or the Marc analysis will fail.

Last Converged Increment

Writes a RESTART LAST instead of a RESTART option. ON by default.

Reauto Complete Unfinished Loadcase

Reauto is OFF by default. This is used for changing conditions on restart of a problem in an autoloading sequence. This places a REAUTO option in the input file. If Complete Unfinished Loadcase is ON then a 1 is placed in the 3rd field of the REAUTO options and the preveious set of history data is completed or teminated. If this is OFF, then any additional data needed for the REAUTO option are extracted from the first Load Step information for the restart job. Only if the Restart Type is set to Read or Read and Write is the REAUTO written or the toggle visible to the user. The Immediate Remesh toggle writes a 1 to the 9th field or the REAUTO and forces a remesh if Global remeshing is turned ON. See note below on example of usage.

Immediate Remesh

Restart from Increment

Defines the increment to be read from the file specified in the Select Restart File form. This is entered in the 3rd data field on the 2nd card of the RESTART option. It is only requested when Restart Type is set to Read or Read and Write. The last increment on the restart file is used for the RESTART LAST option when Last Converged Increment is ON.

Increments Between Writing Defines the number of increments between writing data to the restart file. This is entered in the 2nd data field on the 2nd card of the RESTART option. It is only requested when Restart Type is set to Write or Read and Write. When Last Converted Increment is ON, this is the 4th field of the 2nd data block of the RESTART LAST option. Select Restart File...

Main Index

This brings up a file browser to select the restart file when the Restart Type is set to Read or Read and Write. This file is specified on the command line for invoking the Marc solver using the -r option.

Chapter 3: Running an Analysis 205 Job Parameters

Note:

The most common usage of the REAUTO option is as such: a user runs a job to, say, 50 increments. The job fails to converge or for some reason the user wishes to restart the job with different conditions at, say, 20 increments. The first job must be run and restart information written (Restart Last toggle OFF). The second run is done by reading restart data from increment 20 of the previous job and turning ON the Reauto toggle and the Complete Unfinished Loadcase toggle. The previous loadcase (Load Step) is then terminated or completed at 20 increments and the job restarted using the new load case (Load Step) information for the new job.

Adaptive Meshing In general this form allows for turning ON or OFF adaptive meshing on a Local or Global basis. It writes the appropriate ADAPTIVE and/or REZONING parameter and option or ADAPT GLOBAL option to the Marc input deck. It also allows for ATTACH NODE and SURFACE options to be written to the input deck.

Main Index

206 Marc Preference Guide Job Parameters

General Adaptive Parameters Global adaptive remeshing is mostly used in contact analysis where entire deformable contact bodies must be remeshed because the element distortion becomes too great and the analysis fails to converge. Local remeshing can be used in any general analysis. This table below lists the general adaptivity parameters valid for both Local and Global adaptivity. Local adaptivity allows for mesh refinement about specific user-defined zones of a finite element mesh based on certain criteria. Global adaptivity allows for remeshing of entire deformable contact bodies.

Main Index

Chapter 3: Running an Analysis 207 Job Parameters

General Adaptivity Parameter

Main Index

Description

Adaptivity Type

Selects either Local (default) or Global. Global will remesh only the selected contact bodies. Local will rezone or remesh only the localized areas defined by the selected groups. If Local is selected, the ADAPTIVE option and parameter are included in the input file. For a purely linear analysis with no load increments specified, an ELASTIC parameter is included to force the remeshing. If Global is selected, the ADAPT GLOBAL option is included in the input file and the ADAPTIVE and REZONING parameters. Also, if necessary, the appropriate ELASTICITY or PLASTICITY parameters are written. None is the default in which no adaptive meshing is allowed and all widgets are dimmed.

Upper Bounds Multiplier

This specifies the upper bounds on the problem size before the analysis is automatically terminated. The number of nodes, element, contact segments, contact nodes and fixed degrees-of-freedom are determined automatically from the initial model. The factor will scale these values up for adaptive meshing purposes. The default is to double (2) the size of the model before termination. The scaled maximum number of nodes and elements are placed on the ADAPTIVE parameter in 2nd and 3rd fields respectively. The SIZING parameter continues to contain the number of nodes and elements from the original mesh. The scaled maximum fixed degreesof-freedom is placed in the 5th field of the SIZING parameter and replaces the original number from the original model. The scaled maximum number of contact segments and contact nodes are placed on the CONTACT option in the 2nd and 3rd fields of the 2nd data block respectively. This is determined by selecting between the largest of the (multiplier) times the deformable body entities or the rigid body entities and NOT the sum of the two.

Continue if Upper Bounds Exceeded

This will place a one (1) in the 4th field of the ADAPTIVE parameter and flags the program to continue with the previous mesh if the upper bounds have been exceeded.

Increment Frequency

For Local adaptivity, this parameter flags a remesh after the specified number of increments. When the Adaptivity Type is Local, enters the integer number (default = 1) into the 3rd field of the 2nd data block of the ADAPTIVE option.

208 Marc Preference Guide Job Parameters

General Adaptivity Parameter Snap to Geometry

If this toggle is ON, the ATTACH NODE and SURFACE options are written. Typically, you need to have at least three nodes associated to a curve, or surface/solid edge for geometry snap to work. First the nature of the problem is determined (2D or 3D). For 2D problems, curves are written as NURBs to the SURFACE option and if a surface is supplied, the edges are written as NURBs to the SURFACE option. For 3D problems, surfaces are written as surfaces and if a solid is supplied, the faces are written as surfaces to the SURFACE option. These geometric entities must be placed in the group comprising the adaptive meshing zone in addition to the elements that make up the remeshing zone. All nodes associated to these geometric entities are placed in the ATTACH NODE option. For Local adaptive remeshing only.

Existing Zones

This is a list of adaptive remeshing Zones that have been created. They consist of a Zone name associated to a group (for Local adaptivity) or a deformable contact LBC (for Global adaptivity) and the associated parameters. If you select an existing Zone, you may change its parameters when you press the Apply button. If you rename it in the Zone Name data box, a new Zone with the modified settings will be created.

Zone Name

Enter a Zone name in this box. On Apply, this name will be created and will become visible in the Existing Zones list box.

Select a Group

For Local adaptivity, this list box lists all Groups. The Groups must have a list of elements that define the remeshing zone. This list of elements will be written to the Marc input file as an element set in a DEFINE option for each Zone that is defined. For Global adaptivity, this works the same way except the label is changed to select Deformable Contact LBCs from which the list of elements is derived. This defines the 3rd field of the 3rd data block of the ADAPT GLOBAL by identifying the contact body ID also. The group names must be unique within the first 10 characters. The “_E” qualifier is appended to the group name after the 10th character to denote that an element set (DEFINE) has been created from the entities in the group.

Select a Deformable Contact LBC

Main Index

Description

Apply

Creates the Zone which consists of all the parameters plus the selected Group or Deformable Contact Body.

Delete

Will delete the selected Zone.

OK

Closes the form saving any settings on the form.

Chapter 3: Running an Analysis 209 Job Parameters

General Adaptivity Parameter

Description

Defaults

Will set the default widgets for either Local or Global. It does not set the Adaptivity Type widget however; only the widgets for Local or Global depending on which it is set to.

Cancel

Will close the form without saving any setting on the form.

Note:

Group names associated with each zone are limited to 10 characters. They will be truncated if they exceed this limit. The names are used to define element sets in the input file and are appended by “_E.” For this reason they should be unique in the first 10 characters.

Local Adaptive Meshing The general procedure for setting up a Local adaptive remeshing analysis is as follows: 1. Set the Adaptivity Type to Local 2. Enter a Zone Name. This can be anything you like. 3. Select a Group to be associated to this Zone. This group must be created in the Patran Group application and must contain the nodes and elements of the region of the model in which the adaptive remeshing is to occur. The default_group can be selected in which case the entire model (in general) is part of the remesh Zone. 4. Select Adaptive Mesh Criteria. Use must turn ON the Use Criterion toggle for each particular criteria to be active. You can turn on as many as you like. Only Node in Contact is ON by default because it does not need any user intervention. All other Criteria requires user input to define what will trigger a mesh adaptivity. 5. Press the Apply button to create the Zone with the associated criteria and group. 6. Repeat this for each Zone to be set up. This table list the parameters that are specific to Local adaptivity criteria. See also the forms below:

Main Index

210 Marc Preference Guide Job Parameters

Local Adaptivity Parameter

Description

Maximum Levels to Adapt

This places the given integer in the 2nd field of the 3rd data block of the ADAPTIVE option. Two (2) is the default.

Criteria

Selects the Local adaptive criteria to use. The options are: Mean Strain Energy, Zienkiewicz-Zhu Stress, Zienkiewicz-Zhu Strain Energy, Location within Box, Node in Contact, Maximum Solution Gradient, Equivalent Stress, Equivalent Strain, Equivalent Plastic Strain, User Sub. UADAP. Although Node in Contact is the default, no adaptivity will be done unless at least one of these is turned ON. See next parameter. The selection made here places a 1, 2, 2, 4 or -4, 5, 8, 9, 9, 9, or 10 in the 1st field of the 3rd data block of the ADAPTIVE option respectively.

Use “Criteria” Criteria

This toggle must be ON to use the selected Criteria. The label of this toggle changes and the Criteria is substituted by the name of the Criteria. They are actually separate toggles for each Criteria. The number of Criteria that are turned ON is placed in the 1st field of the 2nd data block of the ADAPTIVE parameter. The 3rd and 4th data blocks are repeated for each Criteria turned ON. All are OFF by default except Node in Contact.

f1, f2, f3, f4, f5, f6

These values are written to the ADAPTIVE option in the 1st through 6th fields of the 4th data block respectively. Some have defaults. Others are dependent on the model size and other factors.

Unrefine

For the Location within a Box criterion, the ability to unrefine the mesh is turned ON with this toggle. If ON, it places a -4 instead of a 4 in the 1st field of the 3rd data block of the ADAPTIVE option.

Absolute

For the Equivalent Stress/Strain criteria, this selects whether f1 or f2, f3 or f4, or f5 or f6 are written.

Mean Strain Energy and Zienkiewicz-Zhu Stress

Main Index

Chapter 3: Running an Analysis 211 Job Parameters

Zienkiewicz-Zhu Strain Energy and Location within Box

Node in Contact and Maximum Solution Gradient

Equivalent Stress and Equivalent Strain

Main Index

212 Marc Preference Guide Job Parameters

Equivalent Plastic Strain and User Sub. UADAP

Element in Cutter Path and Temperature Gradient

Global Adaptive Meshing The general procedure for setting up a Global adaptive remeshing analysis is as follows for any given job: 1. Set the Adaptivity Type to Global 2. Enter a Zone Name. This can be anything you like. 3. Select a Deformable Contact Body to be associated to this Zone. This body must be created in the Patran Loads/BCs application. 4. Select Adaptive Mesh Criteria. (2D or 3D) You must at a minimum: • Select a mesher (Advancing Front is default for 2D) • Give a Target Element Length or Target Number of Elements • Select Remesh Criteria (default is to remesh every 5 increments)

You have control of many parameters to influence the meshing. Press the Apply button to create the Zone with the associated criteria and body. Repeat this for each Zone to be set up.

Main Index

Chapter 3: Running an Analysis 213 Job Parameters

Note:

^äíÜçìÖÜ=óçì=Å~å=ëÉí=ìé=ãìäíáéäÉ=òçåÉë=Ñçê=~=ÖáîÉå=àçÄI=çåäó=çåÉ=ÇÉÑçêã~ÄäÉ=ÄçÇó= Å~å=ÄÉ=~ëëçÅá~íÉÇ=ïáíÜ=~=òçåÉK=fÑ=íÜÉ=ë~ãÉ=ÇÉÑçêã~ÄäÉ=ÄçÇó=áë=~ëëçÅá~íÉÇ=ïáíÜ=ãçêÉ= íÜ~å=çåÉ=òçåÉI=çåäó=íÜÉ=Ñáêëí=çåÉ=ÉåÅçìåíÉêÉÇ=ïáää=ÄÉ=ìëÉÇ=áå=íÜÉ=òÉêçíÜ=áåÅêÉãÉåíK= vçì=ã~ó=ëÉäÉÅí=íÜÉ=òçåÉë=éÉê=iç~Ç=píÉé=ïÜÉå=óçì=ëÉí=ìé=óçìê=äç~Ç=ëíÉééáåÖ= ëÉèìÉåÅÉëK=pÉÉ=Load Step Selection, 332K

Below is a discussion of 2D and 3D Global adaptive meshing. This table lists the parameters that are specific to Global adaptivity. The adaptive meshing is for either 2D or 3D mesher technology. What is presented to you in the form is based on this switch.

Main Index

214 Marc Preference Guide Job Parameters

Global Adaptivity Parameter

Description

Mesher

Selects the mesher to use when a remesh is necessary. Choices are Advancing Front (2D default), Overlay, Delaney, or Tetrahedral (3D default). This places a 2, 3, 4, or 11 in the 1st field of the 3rd data block of the ADAPT GLOBAL option.

Increment Frequency

This parameter flags a remesh after the specified number of increments. Valid for all 2D and 3D meshers. The toggle must be ON to enable the data box. By default this criterion on ON. For Marc Version 2003 or greater, if this is ON, a 1 is placed in the 1st field of the 4th data block. The value (default=5) in the data box is placed in the 2nd field. For Marc Version 2001 or less, a 1 is placed in the 1st field of the 4th data block. The value (default=5) in the data box is placed in the 4th field.

Immediate Remesh

This parameter forces a remesh before the analysis begins. Valid for all 2D and 3D meshers. For Marc Version 2003 or greater, if this is ON, a 7 is placed in the 1st field of the 4th data block. For Marc Version 2001 or less, if this toggle is ON, a one (1) is placed in the 9th field of the 4th data block.

Main Index

Advanced...

This button brings up a form to allow you to set the remeshing criteria This is described in the table and form below.

Target

Previous Mesh Size is the default. For Marc Version 2000 or less, only Element Length is valid. No. of Elements is disabled if not 2001 or greater.

Chapter 3: Running an Analysis 215 Job Parameters

Global Adaptivity Parameter

Description

Element Length: No. of Elements:

This label changes depending on the Target that is selected. If Target is Element Length, the databox accepts a real value. If Target is No. of Elements, the databox accepts integer values. Both are blank by default. If Target Element Length is supplied, this fills out the 2nd field of the 5th data block of the ADAPT GLOBAL option. If No. of Elements is supplied this fills out the 4th field of the 5th data block. If neither is supplied, both fields should be left blank. This flags Marc to use the same number of elements as the previous mesh. Only Target Element Length is valid for Marc Version 2000 or less.

Elements

For Advancing Front: All Quads is the default. All Quads places a zero (0) in the 1st field of the 5th data block of the ADAPT GLOBAL option. All Tris places a two (2) and Mixed places a one (1). For Overlay only All Quads is allowed. For Delaunay only All Tris is allowed.

The Advanced criteria form is valid for all meshers, 2D and 3D, however, only various remesh criteria are valid as described below. All parameters in this table affect the ADAPT GLOBAL keyword option.

Main Index

216 Marc Preference Guide Job Parameters

Main Index

Chapter 3: Running an Analysis 217 Job Parameters

Parameter Strain Change

Description This parameter flags a remesh if a change in equivalent strain greater than that specified is detected. This is only valid for Marc Version 2003 or greater. If this is ON, a 5 is placed in the 1st field of the 4th data block. The value in the data box (an real) is placed in the 3rd field. The default is 0.4.

Element Distortion

This parameter flags a remesh if the element distortion is to be used as a remesh criterion. This is only valid for 2D. The databox value is to indicate the greatest allowable quadrilateral distortion above which triangular elements are added. For Marc Version 2003 or greater, if this is ON, a 2 is placed in the 1st field of the 4th data block. For Marc Version 2001 or less, a one (1) in the 2nd field of the 4th data block and the databox is not applicable.

Penetration

This parameter flags a remesh if penetration is detected. For Marc Version 2003 or greater, if this is ON, a 6 is placed in the 1st field of the 4th data block. The data box default is blank (=2*contact tolerance). If the data box has a value and it is enabled it is placed in the 3rd field. For Marc Version 2001, if this toggle is ON, a one (1) is placed in the 3rd field of the 4th data block and the data box value is placed in the 10th field. For Marc Version 2000 or less, if this toggle is ON, a one (1) is placed in the 3rd field of the 4th data block and the data box is not applicable. This is only available if the mesher is for Quad elements.

Angle Deviation

This parameter flags a remesh if internal element angles change beyond a specified limit. The angle deviation is measured from the undeformed state and is 40 degrees by default. Thisis for 2D meshers only. For Marc Version 2003 or greater, if this is ON, a 3 is placed in the 1st field of the 4th datablock. The value in the databox is placed in the 3rd field. For Marc Version 2001 or less, if this toggle is ON, a one (1) is placed in the 6th field of the 4th data block and the angle deviation for Quads in field 7 and for Tris in field 8.

Main Index

218 Marc Preference Guide Job Parameters

Parameter Aspect Ratio

Description This parameter flags a remesh if the elmeent aspect ratio becomes larger than that specified. This is only valid for Marc Version 2003 or greater for 2D meshers. If this is ON, a 4 is placed in the 1st field of the 4th data block. The value in the data box (an real) is placed in the 3rd field. The default is 10.0.

Main Index

Valume Control

This turns ON the volume control flag for 3D Tetrahedral meshers. A 1 is placed in the 7th field of the 5th data block.

Minimum Element Edge Length

Controls the minimum element edge length. This is blank by default and optional in which case the minimum edge length is 1/3 the Target Element Length. Fills out the 7th field of 5th data block for 2D or the 2nd field for 3D. This is a real value greater than zero. Only valid for Marc Version 2001 or greater and is only valid for the 2D Advancing Front, Delauney and Tetrahedral meshers.

Maximum Element Edge Length

Controls the maximum element edge length for 3D. This is blank by default and optional in which case the maximum edge length is 3 times the Target Element Length. Fills out the 10h field of 5th data block. This is a real value greater than zero. Only valid for Marc Version 2003 or greater.

Curvature Control Subdivisions

This is ON by default with a value of 36 for the Subdivisions for 2D meshers. For 3D meshers it is OFF with a default value of 10. Fills out the 5th field of 5th data block with the Subdivisions value for 2D or the 8th field for 3D. This is an integer value greater than or equal to -1. (-1 is used to obtain uniform outline points.) Only valid for Marc Version 2001 or greater and only valid for the 2D Advancing Front, Delauney and Tetrhedral meshers.

% Change of No. of Elements

Forces the new number of element in the new mesh not to exceed a percentage of the original number of elements. A maximum of five remesh trials are used to fulfill this requirement. This is blank by default and optional in which case no such control is enforced. Fills out the 8th field of 5th data block. This is a real value between 0 and 100. Only valid for Marc Version 2001 or greater and is only valid for the 2D meshers.

Smoothing Ratio

This is 0.8 by default and optional. Fills out the 6th field of 5th data block. This is a real value between zero and one (0-1). Only valid for Marc Version 2001 or greater and only valid for the 2D Advancing Front and Delauney meshers.

Feature Vertex Angle

For Tetrahedral mesher, defaults to 100 degrees and is placed in the 3rd field of the 5th data block. For the 2D meshers, defaults to 120 and is placed in the 3rd field of the 5th datablock.

Chapter 3: Running an Analysis 219 Job Parameters

Parameter

Description

Feature Edge Angle

For the Tetrahdral mesher, defaults to 60 degrees and is placed in the 4th field of the 5th data block.

Coarsening Factor

For the Tetrahedral mesher, defaults to 1.5 for interior elements and is placed in the 5th field of the 5th data block.

Transition Factor

For Advancing Front mesher, placed in the 9th field of 5th data block.

Outside Refining Levels

This is blank by default. Fills out the 2nd field of 5th data block. This is an integer value between zero and two (0-2). Only valid for Marc Version 2001 or greater and only valid for the 2D Overlay mesher.

Inside Coarsening Levels

This is blank by default. Fills out the 3rd field of 5th data block for the 2D Overlay mesher or the 2nd field of the 6th datablock for the 3D Overlay mesher. This is an integer value greater than or equal to zero (2D mesher will always use one (1) regardless of the number you place in the databox). Both the toggle and the databox are only valid for Marc Version 2001 or greater.

Change Element Type

Placed the appropriate element type in the 4th field of the 3rd data block. Some element types are not supported for remeshing. If you experience an error message from Marc stating that the selected element type is not supported, instead of modifying your properites in Patran, specify one of these element types to be used when remeshing is necessary.

User Subroutine File This functions as a normal file browser. Two options exist. The titles are changed to indicate that a FORTRAN file must be selected. The Filter uses a *.f* to find all .f or .for files in the specified directory if the Option is Select Subroutine File. This is the default. When the job is submitted, the run_marc -j jobname -u user_sub

command is ultimately given. The toggle Save Executable can be turned ON in which case the job is submitted with: run_marc -j jobname -u user_sub -sa yes

The new executable will automatically be called by the name of the user subroutine with a .marc appended to the end (.exe on Windows). This executable remains in the submittal directory or scratch directory specified. It is not deleted after job execution. If the Option is Use Existing Executable then the titles and filters are changed as indicated. The job is submitted with: run_marc -j jobname -pr user_sub.marc

where usersub.marc is the executable name (or usersub.exe on Windows).

Main Index

220 Marc Preference Guide Job Parameters

If you turn ON the Remote Exe. toggle, then you can specify the exact path to an existing Marc executable on a remote host (this should only be used when submitting jobs to a remote host). Activation of various subroutines is also flagged from the Activate Routines button. This is explained below.

Main Index

Chapter 3: Running an Analysis 221 Job Parameters

Main Index

222 Marc Preference Guide Job Parameters

Note:

Using an existing, compiled and linked Marc executable is generally only meant to work on a local machine since the executable is machine dependent. It will not work for a remote submittal unless you explicitly identify the remote location of the executable using the Remote Exe. toggle. If the job cannot find the given path on the remote machine, the job will fail.

Activate Subroutines A button called Activate Routines on the Select User Subroutine File brings up this form, which allows for various subroutines can be activated. These are general functions do not require much special input, but are global for the analysis in general. Other functions that are or may be specific to a particular material or element property or to a specific load are generally activated in the Materials, Properties, or Loads/BCs applications.

All toggles are OFF by default.

Main Index

Chapter 3: Running an Analysis 223 Job Parameters

Contact Routines

Main Index

Description

uMOTION

Enters the UMOTION option after the CONTACT option. Not valid for Thermal analysis. Option is not written if no contact bodies exist.

UFRICtion

Enters the UFRICTION option after the CONTACT option. Not valid for Thermal analysis. Option is not written if no contact bodies exist.

UCONTACT

Enters the UCONTACT option after the CONTACT option. Not valid for Thermal analysis. Option is not written if no contact bodies exist.

UGROWRIGID

Write a UMOTION, 2, option after the CONTACT option. This is not valid for Thermal analysis and is not written if no contact bodies exist.

SEPFOR / SEPSTR

If this toggle is ON, writes a comment after the CONTACT option: $....user subroutine sepfor or sepstr has been flagged

UHTCOEf

Enters the UHTCOEF option after the CONTACT option. Only valid for Thermal and Coupled analysis. Option is not written if no contact bodies exist.

UHTCON

Enters the UHTCON option after the CONTACT option. Only valid for Thermal and Coupled analysis. Option is not written if no contact bodies exist.

IMPD, ELEVAR, ELEVEC

If this toggle is ON, a UDUMP option is written with all the nodes and elements of the model specified in the 2nd data block (a blank line indicates all nodes/elements). A negative Post code must have been selected also in the Element or Nodal Output Requests form which then invokes user subroutine PLOTV or UPSTNO.

Material Routines

Description

WRKSLP

Writes a -1 to the 1st field of data block 2 of the WORK HARD option. This is not applicable if TABLES are being used, but only if WORK HARD is written. No data blocks after block 2 are written if this is activated. If this is ON, then it is activated for ALL plastic models.

CRPVIS

Write the VISCO ELAS parameter to the input deck.

224 Marc Preference Guide Job Parameters

Other Routines

Main Index

Description

UTRANform

If this toggle is ON, the UTRANFORM option is written after COORDINATE data. Datablock three includes the list of nodes supplied. However this list is broken up into more than one list if necessary. What determines the division of this list into multiple lists is the reference coordinate frame associated to the nodes. There will be one list for each reference coordinate frame. Thus data block 2 indicates the number of reference coordinate frames and then data block 3 repeats itself for each reference coordinate frame. The actual reference coordinate frame is unimportant as the user subroutine will deal with the real definitions of the coordinate transformations. If the list is left blank, no list is written.

UFXORD

If this toggle is ON, the UFXORD option is written after COORDINATE data. Datablock two includes a list of nodes supplied and can be left blank. This will use the same nodes as UTRAN. Generally these two are not used together.

USDATA

If this toggle is ON, the USDATA option is written with the integer value of the data box placed in the 2nd field near the top of the Model Definition section.

IMPD, ELEVAR, ELEVEC

If this toggle is ON, a UDUMP options is written with all the nodes and elements of the model specified in the 2nd data block (blank line). A negative Post code must have been selected also in the Element or Nodal Output Requests form which then invokes user subroutine PLOTV or UPSTNO.

UFORMS

If this toggle is ON, for the selected MPCs, the Tying type will be written as a negative number, thus invoking User Subroutine UFORMS. This works for all MPC types that write the TYING option except Overclosure (does not work with Explicit, Sliding Surface, and RBE MPCs since they do not write the TYING option).

Chapter 3: Running an Analysis 225 Job Parameters

Rebar Selection When this button is selected a listbox becomes available to associated 2D rebar layers to the job. Please keep in mind the following when running jobs with rebar elements. 1. 2D rebar layers are created using the Rebar Definition tool. See Rebar Definition Tool, 158. 2. Analysis jobs must be axisymmetric or plain strain in order to activate and create rebar elements in the input file. 3. The Marc Version must be set to 2003 to allow selection of 2D rebar layers. 4. Only the 2D rebar layers selected will be translated to the input file. The exception is: 5. If separate rebar element properties have been defined outside of the Rebar Definition tool, they will be translated to the input file regardless and in addition to what is selected here.

Note:

If you delete a 2D rebar layer in the Rebar Definition tool, obviously the association to the job will be lost. This is up to the user to manage.

Radiation Viewfactors This form appears when you press the Radiation Viewfactors button. This button is only available when 1. The Analysis Type is set to Thermal or Coupled analysis.

Main Index

226 Marc Preference Guide Job Parameters

2. Radiation boundary conditions have been created under the Loads/BCs application. This form or application is used to flag a thermal radiation analysis and calculate the radiation viewfactors which are stored in a file and accessed when the job is submitted. The parameters on the form are described here :

Parameter

Description

Thermal Radiation

This is OFF by default. It must be turned ON for a thermal radiation analysis to proceed. All widgets in the View Factor Controls frame below remain disabled if this is OFF. If this is ON, the widgets are enabled. This parameter flags the thermal radiation analysis and means that a RADIATION parameter and the VIEW FACTOR option are placed in the input deck.

Temperature Units

Can be Celsius (default), Kelvin and Fahrenheit. This places a 1, 2, or 3 in the 4th field of the RADIATION parameter, respectively.

Stefan-Bolzmann Constant

Default value is shown above. This is the 4th field of the RADATION parameter.

Number of Rays

This is the number of rays used in the MonteCarlo simulation to determine the radiation viewfactors. This is input to the viewfactor program and not the Marc input deck. This controls the accuracy of the viewfactor calculation. The higher the number, the longer the compute time.

Analysis Type

The is either 2D, 3D or Axisymmetric. This is input to the viewfactor program and not the Marc input deck. 2D analysis refers to analysis in two dimensions such as plane strain. Shell elements are considered 3D analysis since they perform in three dimension even though they are 2D type elements.

Symmetry Planes

If this is ON, then the Symmetry Plane data boxes are activated. Otherwise they are disabled.

Symmetry Plane 1/2/3

These are inputs to the MonteCarlo simulation and are select databoxes for accepting planes in any way that Patran allows selection or definition of a plane. Symmetry Plane 3 is only activated if the Analysis Type is 3D.

Number of Entities

This widget is always disabled and is for informational purposes only. See explanation below.

Note:

RADIATION parameter Field 2 is always set to 2 and field 3 is always set to 0.

Here is an explanation of how this works: 1. The Analysis Type is set to Thermal or Coupled 2. Radiation LBCs are created.

Main Index

Chapter 3: Running an Analysis 227 Job Parameters

3. Thermal Radiation is turned ON in this form; the Temperature Units and Stefan-Boltzman Constant changed if necessary. 4. Change the Number of Rays if desired and set the Analysis Type. At this point, the program detect the existing Radiation LBCs and counts the number of entities in the application regions of all the Radiation LBCs but separated by number of element edges and element faces. This value is reported in the Number of Entities data box. These entities are the number of element edges or element faces (but not both). If a geometric entity is in the application region, it is evaluated to determine the associated element edges/faces. If no Radiation LBCs exist, a message to that effect is issued, however you probably can’t get this far if there are not any defined. If 3D analysis is set but no element faces are available, the number of entities is zero. If 2D or axisymmetric is set but no element edges are available, the number of entities is zero. The reported number does not mix element edges and faces. 5. Set the Symmetry Planes if desired. If the select databox is left empty, that plane is assumed inactive. The input to the program is a location and a vector. 6. Pressing the Calculate button to create the viewfactors. The ratio of the number of emanating rays from any given entity that hit another entity that has radiation defined to those that don not hit it is the view factor (in the most simplistic explanation). While the view factor calculation is going on, a Percent Complete form/widget appears if more than say, 20 entities need viewfactor calculations. If the user presses the Cancel button the calculation is terminated prematurely. 7. The calculation of the thermal radiation view factors is written to a file called jobname.vfs. Note:

If you change the jobname after doing the view factor calculation the correct file will not exist in this case. A warning that the file does not exist is issued if this is the case. You will need to rename the file or recalculate the viewfactors.

When the job is submitted it is submitted with the -vf option specifying the view factor file name as such: run_marc -j jobname -vf jobname.vfs

The Radiation LBCs themselves do not get translated into the input file, but are part of the input to the view factor calculator. The two Temperatures at Infinity (top and/or bottom) are passed into the program and written to the view factor file. Below is a description of the view factor file itself: Block 1 - Header Line 1 10 10 10

int int int

iver nobj nray

Version # Number of objects Number of rays used in computation

Block 2 - Objects Line 1 repeated nobj times 10 10

Main Index

int int

obj eid

Object number Element id

228 Marc Preference Guide Job Parameters

10 15 15

int float float

face tinf tinf

Face or edge number Temperature at infinity top Temperature at infinity bottom

Block 3 - View Factors repeated nobj times Line 1 10 10

int int

obj nz

Emitting object number Number of non zero viewfactors

Line 2 repeated nz times 10 15

int float

obj vfs[4] 1 2 3 4

Incident object number Four view factors Emit out out in in

Incident out in out in

where : out - outer normal of element according to connectivity in - the other side

Note:

For line elements, out means the right hand side as you travel from node 1 to node 2. For shells, out is defined by the right hand rule for the connectivity of the nodes.

Cyclic Symmetry This is a capability in Marc Version 2001 and greater. The translator places the CYCLIC SYMMETRY option in the input deck.

Main Index

Chapter 3: Running an Analysis 229 Job Parameters

Temperature Parameter

Description

Cyclic Symmetry

This toggle turns this option ON. Only if this toggle is ON does the frame and its contents become active for input. If the toggle is OFF, no CYCLIC SYMMETRY data will be written to the input deck.

Cyclic Symmetry Axis

This is a vector that can be selected graphically by all the current methods in Patran. Coord 0.3 (the z-axis) is the default. The three direction cosines are placed in fields 1-3 of the 2nd data block of the CYCLIC SYMMETRY option.

Point on Symmetry Axis

This is a point that must lie on the symmetry axis. If left blank, the origin is used. It can be picked graphically by all the current Patran methods. The coordinates are placed in fields 1-3 of the 3rd data block of the CYCLIC SYMMETRY option.

Number of Repetitions

This is used simply to calculate the Angle. The default is two (2). Thus 360/2 is 180. So 360 is always divided by this number and placed in the Angle data box.

Angle

This is placed in the 1st field of 4th data block. This box is always disabled. The number is calculated and set by the Number of Repetitions.

Suppress Rigid Body Motion If this toggle is ON, a -1 is placed in the 1st field of the 5th data block. If it is OFF, a zero is placed there instead. Cyclic Symmetry is valid for:

Main Index

230 Marc Preference Guide Job Parameters

1. Only continuum elements (solids, 2D solids). However, the presence of beams and shells is allowed, but there is no connection of shells to shells, so that shell part can, for example, be a turbine blade and the volume part can be a turbine rotor. The blade is connected to the rotor and if there are 20 blades, 1/20 of the rotor is modeled and one complete blade. 2. Nonlinear static analysis including remeshing as well as coupled analysis. 3. Pure heat transfer. 4. All analyses involving contact. 5. Eigenvalue analysis such as buckling or modal analysis, harmonic analysis, and transient dynamic analysis. However, there are restrictions in the case of modal analysis which are described in more detain in Marc Volume A: Theory and User Information, Chapter 9, Cyclic Symmetry.

Main Index

Chapter 3: Running an Analysis 231 Load Step Creation

Load Step Creation This subordinate form appears whenever the Load Step Creation button is selected on the Analysis form. A Load Step (or analysis step) is defined by associating a load case, an analysis procedure, output requests, and any associated parameters that guide the solution path for the chosen analysis procedure. Whereas a load case is a collection of loads and boundary conditions for a particular Load Step, a Load Step is a collection of relevant analysis parameters including the associated load case. For instance, an analysis can consist of multiple Load Cases, where perhaps the first Load Case applies a load to half of its maximum over a 10 second time period; a second Load Case does a modal extraction; and the third Load Case takes the load to 100% over 10 more seconds. There is no importance to the order in which the Load Steps are created on this form--they are ordered for the job in the Load Step Selection, 332 form.

Main Index

232 Marc Preference Guide Load Step Creation

Structural, Thermal, and Coupled Solution Types Load Step Widget

Main Index

Description

Solution Type

Lists the available solution types. These vary depending on the Analysis Type (Structural, Thermal, or Coupled). They are listed below for each.

Apply

This button creates the Load Step.

Delete

This button deletes the selected Load Step

Cancel

This button closes the form without making or saving any changes.

Chapter 3: Running an Analysis 233 Load Step Creation

Main Index

234 Marc Preference Guide Load Step Creation

Solution Parameters Each subordinate form for each solution type is shown in this section. Many parameters are common to multiple solution types and are described in the table in the section Common Solution Parameters, 264. Solution Parameters for the following analysis procedures are discussed on the following pages: • Statics, 234 (Structural and Coupled) • Normal Modes, 238 • Buckling, 240 • Transient Dynamic, 242 (Structural and Coupled) • Frequency Response, 245 • Spectrum Response, 247 • Creep, 249 (Structural and Coupled) • Body Approach, 252 (Structural and Coupled) • Static (Single Increment), 254 • Steady State Heat Transfer, 256 • Transient Heat Transfer, 259

Statics This subordinate form appears when the Solution Parameter button is selected on the Analysis form and Static is the Solution Type, which is available for both Structural and Coupled analysis.

Main Index

Chapter 3: Running an Analysis 235 Load Step Creation

Static Parameter Linearity

Description Nonlinear is the default. If Linear is chosen, non-applicable widgets are dimmed. This widget is applicable for both Structural and Coupled analysis.

Nonlinear Geometric Effects Indicates the type of nonlinear geometric approximation to use. The default is Large Displacement / Large Strain which writes the LARGE DISP, UPDATE, and FINITE parameters. Large Displ. (Tot. Lagr.) / Small Strain writes a LARGE DISP parameter only. Large Displ. (Updated Lagr.) / Small Strain writes the LARGE DISP, and UPDATE parameters only. None places none of these in the input file. Advanced allows you greater control over which parameters are written. An Advanced Options button appears when Advanced is selected. The options available here are described under Common Solution Parameters, 264 and override any other settings that the program may normally write. Note that while these settings can be set per Load Step, only the settings of the first Load Step are used.

Main Index

236 Marc Preference Guide Load Step Creation

Static Parameter

Main Index

Description

Follower Loads Follower Forces

Requests that loads be applied to and follow the deformed configuration of the model from increment to increment. If ON (Load Follow Deformations, or Load/Stiffness Follow Deformations, or Loads Follow Deform.(Beginning Incr.)) a 1, 2, or 3, respectively, is placed in the 2nd field of the FOLLOW FOR in input file if ON. In all cases a one (1) is placed in the 3rd field (except as noted below). If OFF (No Follower Forces) a FOLLOW FOR, -1, 1 is written. The -1 indicates that follower forces are OFF. The 1 in the 3rd field indicates to use total loads when defining loads. Loads are generally always placed in the Marc input file as total loads, so all input files usually must have a FOLLOW FOR parameter except when Table style input is used. Follower Loads affects the behavior of distributed loads (pressures). Follower Forces affects the behavior of point loads and if ON, places a 1 in the 4th field.

Treat Loads as

By default all loads are treated as Total Loads. In some instances it may be advantageous to treat the loads as Incremental Loads. This is usually only applicable in the case of Fixed load stepping. Normally Adaptive load stepping requires total loads in which case the incremental setting is ignored except for displacement conditions. To achieve proper behavior with changing displacement condition from Load Step to Load Step, it may be necessary to set this to Incremetal Loads. In this case, the 3rd field of the FOLLOW FOR parameter is left blank or FOLLOW FOR is not written at all if it is not needed.

Cumulative Loads

This is ON by default and only accessible when the Linearity is Linear. If this is OFF, loads are not treated as cumulative from Load Step to Load Step but are treated as separate subcases from which separate solutions are sought. When this toggle is OFF, the ELASTIC parameter is placed in the input file to indicate that repeated matrix back substitution on a series of load vectors is allowed. Not available for Coupled analysis.

Load Increment Parameters...

Load increment parameters for Structural Static analysis appear on a subordinate form. For Coupled analysis, they appear directly on this form. They are described in Load Incrementation Parameters, 266.

Iteration Parameters...

Iteration parameters described in Iteration Parameters, 287.

Contact Table...

Contact Table setup is described in Contact Table, 291. Each Load Step can have its own contact table setup.

Active/Deactive Elements...

This capability is described in Active/Deactive Elements, 300.

Temp./Axisymm. Options...

Specifying an external temperature loading file or referencing a post file for axisymmetric to 3D results mapping is described in Pre State Options, 302.

Chapter 3: Running an Analysis 237 Load Step Creation

Static Parameter

Main Index

Description

Superplastic Forming...

Parameters for activating and setting up a superplastic forming analysis are available from this form. It is only valid if the Loads Follow Deformations option menu is set to anything but No Follower Forces. In other words, follower forces must be turned ON. These parameters are discussed in Superplastic Forming, 308. Not available for Coupled analysis.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form keeps the settings as they were before the form was opened.

238 Marc Preference Guide Load Step Creation

Normal Modes This subordinate form appears when the Solution Parameter button is selected for Normal Modes (or Static with incremental extraction).

Note:

Main Index

You must perform a Normal Modes analysis before you can do a Transient Dynamic analysis using linear modal superposition.

Chapter 3: Running an Analysis 239 Load Step Creation

If the selected bñíê~Åíáçå=jÉíÜçÇ is Inverse Power Sweep, then the following parameters may be defined. Parameter Name

Main Index

Description

Number of Modes

Defines the number of modes to extract. This is entered in the 3rd data field of the DYNAMIC option.

Max # of Iterations per Mode

Defines the maximum number of iterations that are allowed for the extraction of any mode. This is entered in the 1st data field of the second card of the MODAL SHAPE option.

Convergence Tolerance

Defines the maximum allowable relative difference between the eigenvalues (frequency squared) for convergence. This is entered in the 2nd data field of the 2nd data block of the MODAL SHAPE option. Default is 1e-5.

Initial Frequency

Defines the initial shift frequency (cycles per unit of time). This entered in the 3rd data field of the second card of the MODAL SHAPE option. Default is zero.

Highest Frequency

Defines the highest frequency to be extracted in cycles per unit of time. This is entered in the 4th data field of the 2nd data block of the MODAL SHAPE option. This is optional and, if left blank, extraction will end when the number of modes requested is reached, otherwise extraction ends when this frequency is reached.

Auto Shift

Requests that the shift be updated periodically. When this is not selected, the 5th data field of the second card of the MODAL SHAPE option is set to the number of modes to extract. OFF by default.

Number of Modes per Shift

Defines the number of modes that are extracted per shift. This is entered in the 5th data field of the second card of the MODAL SHAPE option. It is only requested when Auto Shift is selected. The default is 5.

Auto Shift Parameter

Defines the automatic shift parameter. The new shift point (in frequency squared) is calculated by multiplying the shift parameter by the square of the difference between the two highest extracted frequencies and adding this product to the highest frequency squared. The shift parameter is entered in the 6th data field of the second card of the MODAL SHAPE option. This is only requested when Auto Shift is selected. The default is 1.0.

240 Marc Preference Guide Load Step Creation

If the selected Extraction Method is Lanczos, then the following parameters may be defined. Parameter Name

Description

Number of Modes

For Lanczos, defines the number of modes to extract. This is entered in the 3rd data field of the DYNAMIC parameter if this is the 1st Load Step. All subsequent Load Steps, this is placed in the 3rd field of the 2nd data block of the MODAL SHAPE option.

Lowest Frequency

For Lanczos, defines the lowest frequency to be extracted in cycles per unit of time. This is entered in the 1st data field of the 2nd data block of the MODAL SHAPE option.

Highest Frequency

For Lanczos, defines the highest frequency to be extracted in cycles per unit of time. This is entered in the 2nd data field of the 2nd data block of the MODAL SHAPE option.

Sequence Checking

For Lanczos, requests that Sturm sequence checking be performed on the extracted eigenvalues. This sets the 4th data field of the 2nd data block of the MODAL SHAPE option to one (1) if ON, otherwise it is zero (0). OFF by default.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form keeps the settings as they were before the form was opened.

Note:

Parameters specified on the DYNAMIC parameter can only be specified once which is determined by the first Load Step. Everything that goes on the MODAL SHAPE option can vary by Load Step.

Note:

When Normal Modes is requested, a RECOVER card is written according to Output Requests as a step after the MODAL SHAPE option.

Buckling This subordinate form appears when the Solution Parameter button is selected for Buckling or Static (with incremental extraction). In all cases, a BUCKLE option is written to the History section. The BUCKLE parameter has a one (1) placed in the 4th data field.

Main Index

Chapter 3: Running an Analysis 241 Load Step Creation

The parameters are described in the table below. Note:

Main Index

When Buckling is requested, a RECOVER card is written according to Output Requests as a step after the BUCKLE option.

242 Marc Preference Guide Load Step Creation

Extraction Parameter

Description

Max # of Modes

Defines the maximum number of buckling modes to extract. This is entered in the 2nd data field of the BUCKLE parameter option. Default set to five (5).

Max # of Modes w/ Positive Eigenvalues

Defines the maximum number of buckling modes to extract that have positive critical load factors. This is entered in the 3rd data field of the BUCKLE parameter. Default set to one (1).

Max # of Iterations per Mode

Defines the maximum number of iterations that may be used to extract a buckling mode. This is entered in the 1st data field of the 2nd data block of the BUCKLE history option. Not used for Lanczos and a zero is entered.

Convergence Tolerance

Defines the maximum allowable relative difference between critical load factors for convergence. This is entered in the 2nd data field of the 2nd data block of the BUCKLE history option. This is not used for Lanczos and a zero should be entered.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form keeps the settings as they were before the form was opened.

Note:

Parameters specified on the BUCKLE parameter can only be specified once which is determined by the first Load Step. Everything that goes on the BUCKLE option can vary by Load Step.

Transient Dynamic This subordinate form appears when the Solution Parameter button is selected on the Analysis application form when Transient Dynamic is the Solution Type, which is available for both Structural and Coupled analysis.

Main Index

Chapter 3: Running an Analysis 243 Load Step Creation

Dynamic Parameter

Description

Linearity

Nonlinear is the default. The Time Integration Method can only be Direct when the Linearity is Nonlinear. For Linear, the only things applicable are Load Increment Parameters, Activate/Deactive Elements, and Temperature File. All other widgets are dimmed.

Time Integration Method

The Time Integration Method can be Direct or Modal. Direct is the default. Modal is not applicable for Nonlinear. If Modal is selected, a Normal Modes analysis is a required Load Step before the Transient Dynamic Load Step. This setting is not applicable for Coupled analysis - it must be Direct - so the widget is not presented.

Nonlinear Geometric Effects Same as for Statics, 234.

Main Index

Follower Loads Follower Forces

Same as for Statics, 234.

Treat Loads as

Same as for Statics, 234.

244 Marc Preference Guide Load Step Creation

Dynamic Parameter Load Increment Parameters...

Load increment parameters for Structural Transient Dynamic analysis appear on a subordinate form. For Coupled analysis, they appear directly on this form. They are described in Load Incrementation Parameters, 266.

Iteration Parameters...

Iteration parameters described in Iteration Parameters, 287.

Contact Table...

Contact Table setup is described in Contact Table, 291. Each Load Step can have its own contact table setup.

Active/Deactive Elements...

This capability is described in Active/Deactive Elements, 300.

Temp./Axisymm. Options...

Specifying an external temperature loading file or referencing a post file for axisymmetric to 3D results mapping is described in Pre State Options, 302.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form and keeps the settings as they were before the form was opened.

Note:

Main Index

Description

A DYNAMIC parameter is written to the Parameter section for Transient Dynamics.

Chapter 3: Running an Analysis 245 Load Step Creation

Frequency Response This subordinate form appears when the Solution Parameter button is selected when then solution is Frequency Response.

The HARMONIC parameter is written with 3rd, 4th and 5th fields filled in from information of the loads and boundary condition of the model. The 6th field is one (1) always. If damping material properties have been defined, a one (1) is placed in the 2nd field.

Main Index

246 Marc Preference Guide Load Step Creation

Freq. Resp. Parameter Large Displacement

Requests large displacement formulation. This generates the LARGE DISP parameter used in dynamic solution sequence. This is OFF by default. This is ignored if a step before this has already turned it ON.

Lowest Excitation Freq.

Defines the excitation frequency in Hz. for the first vibration analysis. This is entered in the 1st field on the 2nd data block of the HARMONIC history option.

Excitation Freq. Interval

Defines the frequency interval in Hz. for subsequent vibration analysis. This is entered in the 2nd field on the 2nd data block of the HARMONIC history option.

Number of Excitation Frequencies

Defines the number of vibration analyses to perform. This determines the highest excitation frequency which is entered in the 3rd field on the 2nd data block of the HARMONIC history option.

Log Increments

Turns ON the logarithmic frequency increments on the HARMONIC history option (field 4).

Use Complex Damping Matrix Inclued Inertia Effects

Turns these features ON on the HARMONIC parameter. You must have damping in your model for the first to have an effect. The second is used in the calculation of the harmonic reaction forces.

Note:

Main Index

Description

A Frequency Response analysis Load Step can follow any pre-stressing step. The selected load case for the Frequency Response analysis is used to determine the amplitude of the excitation loads.

Chapter 3: Running an Analysis 247 Load Step Creation

Spectrum Response This subordinate form appears when the Solution Parameter button is selected for Spectrum Response solutions.

Main Index

248 Marc Preference Guide Load Step Creation

Spectral Resp. Parameter

Main Index

Description

Large Displacement

Requests large displacement formulation. This generates the LARGE DISP parameter used in dynamic solution sequence. This is OFF by default. This is ignored if a step before this has already turned it ON.

Number of Modes for Spectral Response

Defines the number of modes to use in the spectral response analysis. This is entered in the 1st field on the 2nd data block of the SPECTRUM history keyword option.

Chapter 3: Running an Analysis 249 Load Step Creation

Spectral Resp. Parameter

Description

Weighting Factors for Translational Displacement

Defines the weighting factor associated with the translational degrees-of-freedom. This is entered on the 3rd data block of the SPECTRUM history option in fields 1, 2, and 3.

Weighting Factors for Rotational Displacement

Defines the weighting factor associated with the rotational degrees-of-freedom. This is entered on the 3rd data block of the SPECTRUM history option in field 4, 5 and 6.

Displacement-Response Spectrum

Displays the fields that are available to define displacement response spectrum. By default, the first in the list is selected. Defines the displacement response spectrum as a frequency dependent field (cycles/time). This information is entered on the 3rd data block of the RESPONSE SPECTRUM option. The number of points in this field is entered on the RESPONSE parameter in the 2nd field.

Note:

Must have a modal extraction (Normal Modes) step before this step.

Creep A CREEP option constitutive material model must exist for a Creep analysis to proceed. This solution procedure is valid for both Structural and Coupled analysis.

Main Index

250 Marc Preference Guide Load Step Creation

Each widget is described below.

Main Index

Chapter 3: Running an Analysis 251 Load Step Creation

Parameter

Description

Procedure

The Creep solution requires a CREEP parameter. The default is Explicit Creep. This places nothing in any of the fields of the CREEP parameter. For Implicit Creep, it depends on the Creep Method selected.

Creep Method

For Implicit Creep only. This pull down should dim or be hidden for Explicit Creep. The default is Elastic Tangent. If Secant Tangent or Radial Return, this places a one (1) or a (2) into the 5th field of the CREEP parameter. All other fields should be blank.

Scale to 1st Yield

This puts a SCALE parameter in the input deck. It is a flag to force the first increment (increment zero) to take the load up to the yield point. This requires that the load options be placed in the Model Definition section. This parameter only affects the first Load Step selected. Subsequent Load Steps should ignore this if it is ON. Not used in Coupled analysis.

fåÅêÉãÉåí=qóéÉ

This is either Adaptive, Adaptive Creep, Adaptive Thermal, or Fixed. Adaptive is the default. This causes an AUTO STEP to be written the History section. The others cause AUTO CREEP, CREEP INCREMENT or AUTO LOAD to be written to the History section, respectively. This an the other associated load increment parameters are discussed in Load Incrementation Parameters, 266.

Nonlinear Geometric Effects Same as for Statics, 234 Loads Follow Deformations

Same as for Statics, 234

Treat Loads as

Same as for Statics, 234.

Iteration Parameters...

Iteration parameters described in Iteration Parameters, 287.

Contact Table...

Contact Table setup is described in Contact Table, 291. Each Load Step can have its own contact table setup.

Active/Deactive Elements...

This capability is described in Active/Deactive Elements, 300.

Temp./Axisymm. Options...

Specifying an external temperature loading file or referencing a post file for axisymmetric to 3D results mapping is described in Pre State Options, 302.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form and keeps the settings as they were before the form was opened.

Note:

Main Index

Viscoelastic solutions are handled by defining Viscoelastic material properties. A Creep procedure is not necessary; only a standard Nonlinear Static solution.

252 Marc Preference Guide Load Step Creation

Body Approach This procedure is available for both Structural and Coupled analysis. It allows you to position rigid bodies to just touch deformable bodies before beginning a subsequent Load Step. It is used commonly in multi-forming simulations where bodies are brought just into contact before the analysis begins. They can also be release using a contact table. See Contact Table, 291.

Main Index

Chapter 3: Running an Analysis 253 Load Step Creation

Parameter

Description

Total Time

This places a TIME STEP option in the Load Step with the time step value being the total time specified here.

Synchronized

If this toggle is OFF, the APPROACH option is written. If this toggle is ON, the SYNCHRONIZE option is written. The difference between the two is in how to approach the rigid bodies. By default all bodies are moved until they come in contact. However, if you Synchronize the movement, then when the first rigid body comes into contact, the rest stop moving when the first body contacts another.

Contact Table

This button brings up the standard Contact Table form and a contact table should be defined for this load step in the normal fashion. See Contact Table, 291.

In addition to the above options, if no TABLEs are being used in the CONTACT option, then a MOTION CHANGE option is written as the last entry of the Load Step. Rigid bodies are brought into contact only for bodies with non-zero velocity or position control. If a field is used to define motion change in the contact definition, the proper total time is tracked from all previous Load Steps such that the correct velocity/position is extracted into the MOTION CHANGE option. No other LBCs are written even if they appear in the associated load case.

Main Index

254 Marc Preference Guide Load Step Creation

Static (Single Increment) This analysis procedure allows you to perform static analysis in a single load increment if this is the only Load Step selected for a particular analysis. (In this case, only increment zero is run and no History definition is written to the input deck.) Or it allows you to perform a single load increment to be inserted between any existing Load Steps. (All loads are written to the History section in this case but no AUTO load control options are written.)

This Load Step has no Solution Parameters form. If the first selected Load Step is Linear (Single Incr.) then all the loads and boundary conditions (LBCs) of the associated load case are placed in the Model Definition section. If this is the only Load Step, then no History section is written except if Direct Text Input (DTI) is present. Then the DTI is placed in the History section with a CONTINUE option ending the deck.

Main Index

Chapter 3: Running an Analysis 255 Load Step Creation

If this is not the first or only Load Step, then the LBCs from the associated load case are placed between CONTINUE cards in the normal manner, including Output Requests and DTI but no load incrementation parameters (i.e., AUTO LOAD/INCREMENT/STEP) thus forcing a single increment.

Main Index

256 Marc Preference Guide Load Step Creation

Steady State Heat Transfer This subordinate form appears when the Solution Parameter button is selected for the Steady State Heat Transfer solution.

The HEAT parameter is automatically placed in the input file for Heat Transfer analysis types. Input to the HEAT parameter is acquired from Element Properties (field 2) and field 4 is set to two (2).

Main Index

Chapter 3: Running an Analysis 257 Load Step Creation

Heat Parameter

Description

Maximum Error in Temperature

Defines the maximum error in temperature used for property evaluation. Default is 0.0 which flags a bypass of this test. This is entered in the 3rd field of the 3rd data block of the CONTROL option.

Number of Increments

This is the number of fixed increments for this Load Step. It is blank by default and is optional. It can be left blank. A STEADY STATE or TRANSIENT NON AUTO option is written according to the usage scenarios outlined below.

Total Time

This is the total time of the Load Step and is blank by default and is optional. It can be left blank. A TIME STEP or TRANSIENT NON AUTO option is written according to the usage scenarios outlined below.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form keeps the settings as they were before the form was opened.

Usage Scenarios

The following scenarios are possible when writing in input file for Steady State Heat Transfer: Static Load Case - Steady State Heat Transfer # of Increme nts blank

Total Time blank

Remarks • Writes a single increment using the STEADY STATE option in the

History section. • Loads are written as total loads.

supplied

blank

• Writes a STEADY STATE option for each increment requested. • Load values are divided by the number of increments requested but written

as total loads increasing each increment until the total load is reached at the last increment. blank

supplied

• Writes a single increment using the TRANSIENT NON AUTO option in

the History section with the given time value. • Loads are written as total loads.

Main Index

258 Marc Preference Guide Load Step Creation

Static Load Case - Steady State Heat Transfer # of Increme nts

Total Time

supplied

supplied

Remarks • Writes a STEADY STATE option for each increment requested. • Writes a TIME STEP options for each increment the value of which is the

total time divided by the number of increments. • Load values are divided by the number of increments requested but written

as total loads increasing each increment until the total load is reached at the last increment. Time Dependent Load Case - Steady State Heat Transfer # of Increme nts blank

Total Time blank

Remarks • Writes an increment for each time point in the referenced field(s) using the

STEADY STATE option. • Writes a TIME STEP option for each increment (or point in the field(s))

the value of which is the time between points. • The first point of the field(s) is written in the Model Definition section

unless there are no fields associated to any loads. In this case it is treated like the Static case. supplied

blank

• Identical to the above case except only the number of points specified as

the number of increments are written; truncates the signal if increments are less than points in field. blank

supplied

• Also identical first case above except now it is the time that drives what

increments are written according to these scenarios. • 1. If the time is greater than or equal to the largest time in the field, all steps

are written. • 2. If the time is less than the total time of the signal, then the only steps up

to that time are written. If the time falls between points, the last point is interpolated. supplied

supplied

• Writes the STEADY STATE and TIME STEP options for every

increment. • Increments determined by dividing the total time by the number of

increments and interpolates the field(s) at those new incremental time values with linearly interpolated load values.

Main Index

Chapter 3: Running an Analysis 259 Load Step Creation

Transient Heat Transfer This subordinate form appears when the Solution Parameter button is selected for the Transient Heat Transfer solution.

The HEAT parameter is automatically placed in the input file for Heat Transfer analysis types. Input to the HEAT parameter is acquired from Element Properties (field 2) and field 4 is set to two (2).

Main Index

260 Marc Preference Guide Load Step Creation

Heat Parameter

Description

Maximum Temperature Change Allowed

Defines the maximum nodal temperature change allowed per increment. Default is 20.0. This is entered in the 1st field of the 3rd data block of the CONTROL option.

Maximum Temperature Change between Reassembly

Defines the maximum nodal temperature change allowed before properties are reevaluated and matrices reassembled. Default is 100.0. This is entered in the 2nd field of the 3rd data block of the CONTROL option.

Maximum Error in Temperature

Defines the maximum error in temperature used for property evaluation. Default is 0.0 which flags a bypass of this test. This is entered in the 3rd field of the 3rd data block of the CONTROL option.

Time Step Type

This can be Adaptive, Adaptive Thermal or Fixed. Different scenarios are laid out below. The latter two control whether a TRANSIENT or a TRANSIENT NON AUTO option is used, respectively. The former uses the AUTO STEP option. Widgets for the other two are discussed here. Adaptive time stepping incrementation is discussed in Load Incrementation Parameters, 266.

Initial Time Step Size or

For Adaptive Thermal, this is the suggested trial time step size. It is entered into the 1st field of the 2nd data block of the TRANSIENT option. A default of 10.0 is set.

Time Step Size

For Fixed the label changes. This is the actual desired time step size. It is 10.0 by default. This will cause a NON AUTO to be written in the 2nd field of the 1st data block of the TRANSIENT option, thus forcing a fixed time step size. The time step size is written to the 1st field of the 2nd data block.

Main Index

Total Time

This is the total time period of the transient solution. This is blank by default. This is optional and, if left blank, will be determined by the longest time in a referenced time dependent load. For non-time dependent loads, the total time will be the Time Step Size if left blank. This is the 2nd field of the 2nd data block of the TRANSIENT option.

Maximum # of Steps

This is entered into the 3rd field of the 2nd data block of the TRANSIENT option. It can be left blank which will default to the Initial Step Size divided by the Total Time by Marc automatically.

Temperature Limits

Sets whether transient analysis should finish if all nodal temperatures are above or below a given value. The default is None and can be set to Minimum or Maximum also. This places a 0, 1, or -1 in the 6th field of the 2nd data block of the TRANSIENT option, respectively.

Chapter 3: Running an Analysis 261 Load Step Creation

Heat Parameter

Description

Minimum/Maximum Nodal Temperature

Temperature at which transient analysis will finish if all nodal temperatures are above or below. This is hidden unless Temperature Limits is set to Minimum or Maximum. This is entered into the 7th field of the 2nd data block of the TRANSIENT option. The label also changes depending on the setting of Temperature Limits.

OK

Closes the form and saves any settings.

Defaults

Resets the widgets on the form to their defaults.

Cancel

Closes the form and keeps the settings as they were before the form was opened.

The CONTROL card is written to the Model Definition section if this is the first Load Step. If in subsequent Load Steps this information changes, it is written to a CONTROL card in the History section. The CONTROL card is not written unless non-linear conditions are encountered. These are flagged by the presence of radiation, convection, specific heat, conductivity (temperature dependent material properties). If the problem is detected to be completely linear, no CONTROL card is written which speeds up computation time. Usage Scenarios

The following scenarios are possible when writing in input file for Transient Heat Transfer. Note that a time step or initial time step must be supplied.

Main Index

262 Marc Preference Guide Load Step Creation

Static Load Case - Fixed Load Stepping Time Step Size supplied

Total Time

Remarks • Writes a single increment to the History section using the TRANSIENT

blank

NON AUTO option. • Total time defaults to the time step size. This can result in a Steady State

solution if the time step size is high enough. supplied

supplied

• Writes a single increment to the History section using the TRANSIENT

NON AUTO option. • The total time and time step size are both written on the TRANSIENT

NON AUTO option. Time Dependent Load Case - Fixed Load Stepping Time Step Size supplied

Total Time

Remarks • An increment is written out for each point of the time dependent load.

blank

• The total time written to the TRANSIENT NON AUTO is determined by

the incremental time between each point in the time dependent load. • If the time step size is greater than the incremental time between points, the

time step size is reduced to the incremental time for that increment. supplied

supplied

• Writes the time dependent load at each point for the specified period of

time using TRANSIENT NON AUTO as in the previous case. • Load is truncated if total time is shorter than actual signal and interpolated

at the last point if necessary. • If total time is longer, only what is available is written.

Static Load Case - Adaptive Thermal Load Stepping Time Step Size supplied

Total Time blank

Remarks • Writes a single increment to the History section using the TRANSIENT

option. • Total time defaults to the initial time step size.

supplied

supplied

• Writes a single increment to the History section using the TRANSIENT

option. • The total time and initial time step size are both written on the

TRANSIENT option.

Main Index

Chapter 3: Running an Analysis 263 Load Step Creation

Time Dependent Load Case - Adaptive Thermal Load Stepping Time Step Size supplied

Total Time blank

Remarks • An increment is written out for each point of the time dependent load. • The total time written to the TRANSIENT option is determined by the

incremental time between each point in the time dependent load. • If the initial time step size is greater than the incremental time between

points, the initial time step size is reduced to the incremental time for that increment. supplied

supplied

• Writes the time dependent load at each point for the specified period of

time using TRANSIENT as in the previous case. • Load is truncated if total time is shorter than actual signal and interpolated

at the last point if necessary. • If total time is longer, only what is available is written.

Note:

Main Index

Adaptive scenarios would be equivalent to Adaptive Thermal scenarios above.

264 Marc Preference Guide Load Step Creation

Common Solution Parameters The following forms and tables show common items to many of the Solution Parameter forms. The following subordinate forms that appears on the Solution Parameter forms are described below. • Advanced Options (Geometric Effects), 264 for Statics, Transient Dynamics, and Creep for

Structural and Coupled analyses. • Load Incrementation Parameters, 266 for Statics, Transient Dynamics and Transient Heat

Transfer (Adaptive). • Iteration Parameters, 287 • Contact Table, 291 • Active/Deactive Elements, 300 • Pre State Options, 302 • Superplastic Forming, 308 for Statics only.

Advanced Options (Geometric Effects) For Statics, Transient Dynamics, and Creep analyses, you may override the normal default geometric effects parameters that get written to the input deck by using this form. Caution should be used that the appropriate parameters are used depending on the type of analysis. With this form it is possible to set inappropriate parameters. In most other instances, the program tries to set appriate parameters that will allow the job to run.

Main Index

Chapter 3: Running an Analysis 265 Load Step Creation

Geometric Parameter

Main Index

Description

Large Displacements

Writes the LARGE DISP parameter to the input deck to indicate large displacement methodologies are to be used. ON by default.

Plasticity Procedure

Writes the PLASTICITY parameter to the input deck. Choices are Large Strain Additive (default) or Large Strain Multiplicative which writes PLASTICITY, 3 or PLASTICITY, 5, respectively. If Small Strain is selected, no PLASTICITY parameter is written. Using PLASTICITY, 3 is the same as using LARGE DISP, UPDATE, and FINITE in the same input deck. So setting a number of these widgets in this form can be redundant. Using the multiplicative method is required with Herrmann elements and nonlinear elastic-plastic materials.

Elasticty Procudre

Writes the ELASTICTY parameter to the input deck. This parameter is generally only necessary when using rubber materials (elastomers). Choices are Small Strain (default), in which case no ELASTICITY parameter is written or Large Strain - Total Lagrange and Large Strain - Updated Lagrange, which write ELASTICITY, 1 and ELASTICITY, 2, repsectively. Herrmann elements generally require ELASTICITY, 2.

Updated Lagrange

Writes the UPDATE parameter to the deck indicating to use the Updated Lagrangian formulation for large displacements as opposed to the Total Lagrangian. Note that PLASTICITY, 3 invokes this also.

266 Marc Preference Guide Load Step Creation

Geometric Parameter

Description

Large Beam Rotations

Writes the UPDATE,0,1 parameter to the deck indicating to use large beam rotations in conjuction with the Updated Lagrangian procedure.

Large Strains

Writes the FINITE parameter to the input deck indicating to use large strain formulation, normally only necessary for rubber (elastomeric) materials and large flow plasticity. Note that PLASTICITY, 3 invokes this also.

Caution: While these settings can be set differently for each Load Step, only the settings of the first Load Step selected are used in the analysis. Load Incrementation Parameters Load and time step incrementation parameters for Statics and Transient Dynamics appear on this subordinate form. In some cases this information appears directly on the Solution Parameters form:

Main Index

Chapter 3: Running an Analysis 267 Load Step Creation

Note:

This form for Adaptive load/time incrementation can slightly change between Statics and Transient Dynamics (or other solutions) and differences are noted in the table below. Different usage scenarios can result depending on whether static or time dependent loading is used. These are outlined in Usage Scenarios, 282.

This table indicates which Marc load or time stepping option is used for a given solution type and load/time incrementation method. Unless otherwise indicated, the default is Adaptive

Main Index

268 Marc Preference Guide Load Step Creation

.

Solution

Fixed

Adaptive Creep

Static (Structural)

AUTO LOAD

AUTO STEP (no arclength method) AUTO INCREMENT (with arclength method)

AUTO THERM

N/A

Static (Coupled)

TRANSIEN T NON AUTO

AUTO STEP

TRANSIENT

N/A

Normal Modes N/A

N/A

N/A

N/A

Buckling

N/A

N/A

N/A

N/A

Transient Dynamics (Structural)

DYNAMIC CHANGE

AUTO STEP

N/A

N/A

Transient Dynamics (Coupled)

DYNAMIC CHANGE

AUTO STEP

TRANSIENT

N/A

Frequency Response

N/A

N/A

N/A

N/A

Harmonic Response

N/A

N/A

N/A

N/A

Creep (Structural)

CREEP INCREMEN T

AUTO STEP

AUTO THERM CREEP

AUTO CREEP

Creep (Coupled)

CREEP INCREMEN T

AUTO STEP

AUTO THERM CREEP

AUTO CREEP

Body Approach

N/A

N/A

N/A

N/A

Linear (Single Incr.)

N/A

N/A

N/A

N/A

Steady State Heat

STEADY STATE

N/A

N/A

N/A

Transient Heat

TRANSIEN T NON AUTO

AUTO STEP

TRANSIENT

N/A

The following are described below: • Adaptive (with Arclength Method), 269

Main Index

Adaptive Thermal

Adaptive

Chapter 3: Running an Analysis 269 Load Step Creation

• Adaptive (no Arclength Method), 271 • Adaptive Load Stepping Criteria, 274 • Adaptive Thermal, 276 • Adaptive Creep, 278 • Fixed Load Incrementation, 279 • Usage Scenarios, 282 Adaptive (with Arclength Method)

The following table describes adaptive load incrementation for Static (Structural) analysis when an Arclength Method is set. This writes the AUTO INCREMENT option.

Main Index

270 Marc Preference Guide Load Step Creation

Adaptive Increment Parameter

Main Index

Description

Arclength Method

Selects the arclength root procedure. The default is Modified Riks/Ram. This places a 1, 2, 3, or 4 in the 8th field of the 2nd data block of the AUTO INCREMENT option. If None is selected the form updates as shown below. An AUTO STEP is used instead of AUTO INCREMENT. For Transient Dynamics, this is the only option available for adaptive load incrementation.

Automatic Cutback

This is a feature for Marc 2000 or higher. It is not available if the Marc Version is less than 2000. It is ON by default. If an increment does not converge, a restart from the last increment cuts the increment size in half. This writes a RESTART LAST option to the input file with a one (1) in the 1st field of the 2nd data block. Marc automatically handles the restart from the last increment.

Number of Cutbacks

This is associated with Automatic Cutback. It writes the integer number (defaulted to 3) to the 9th field of the AUTO INCREMENT option for the Adaptive increment type. This parameter determines how many times a cutback is allowed.

Initial Fraction of Load Applied to 1st Increment

Places the value (default is 0.1) in the 1st field of the 2nd data block of the AUTO INCREMENT option. This is the fraction of the total load that should be applied in the first iteration of the first increment.

Max. Fraction of Load Applied in Any Increment

Places the value (default is 1.0) in the 4th field of the 2nd data block of the AUTO INCREMENT option. This is the maximum fraction of the load that can be applied in any increment.

Max/Min Ratio Arc Length / Initial Arc Length

Places this value in the 5th and 7th field of the 2nd data block of the AUTO INCREMENT option, respectively. It is used to define the minimal arclength. The default is 0.01.

Total Time

This is the total time of the analysis for a particular step. It defaults to one (1) if left blank for static load cases. For time dependent load cases, the total time is the length of time between distinct time points if left blank. Otherwise the actual value is used (not recommended because it can’t be variable). This is the 6th field of the 2nd data block of the AUTO INCREMENT option.

Max. # of Increments

Places this integer value in the 2nd field of the 2nd data block of the AUTO INCREMENT option. Program will end if this value is exceeded.

Chapter 3: Running an Analysis 271 Load Step Creation

Adaptive Increment Parameter Scale to 1st Yield

Description Only applicable to Nonlinear Statics when the Geometric Effects are Small Displacements and Strains. You must supply a yield stress when defining materials. This puts a SCALE parameter in the input deck. It is a flag to force the first increment (increment zero) to take the load up to the yield point. This requires that the load options be placed in the Model Definition section. This parameter is not be written to the input file for time dependent load cases and only affects the first Load Step selected. Subsequent Load Steps ignore this if it is ON. This is only valid for Small Strain/Displacement.

Eigenvalue Extractions

Modal or Buckling extractions can be done at specified load percentages for Linear or Nonlinear Statics. They are both OFF by default. Only one or the other can be ON, but not both. A DYNAMIC or BUCKLE parameter is written if ON.

List of Increments for Extraction:

This is a list of the increments at which eigenvalue extractions should be performed. If the list is 10, 30, 50 then buckling or modal extraction is done at indrement 10, 30, and 50.

Eigenvalue Extract Parameters

This brings up a subordinate form for selecting the eigenvalue extraction parameters. This form is identical to that for Normal Modes or Buckling solution parameter forms. For Modal Eigenvalue Extraction, see Normal Modes, 238. For Buckling Eigenvalue Extraction see Buckling, 240.

OK

Closes form and saves set information.

Defaults

Set the form back to its defaults.

Cancel

Closes form and does not save changed information.

Adaptive (no Arclength Method)

If None is selected as the Arclength Method, the form updates as shown below for Static (Structural and Coupled) analysis. This method writes the AUTO STEP option. This method is also used for Transient Dynamics and Creep Analysis (Structural and Coupled) and Transient Heat Transfer although the from widgets may appear slightly different than below or appear directly on the Solution Parameters form, however the widget functions and names are identical.

Main Index

272 Marc Preference Guide Load Step Creation

Adaptive Increment Parameter

Main Index

Description

Trial Time Step Size

Field 1 of 2nd data block of AUTO STEP option. Blank by default. Marc default is 1% of Total Time if left blank.

Time Step Scale Factor

Field 6 of 3rd data block of AUTO STEP option. Default is 1.2. Indicates load will be allowed to be scaled up by 20% each increment if possible.

Minimum Time Step

Field 5 of 2nd data block of AUTO STEP option. Blank by default. Marc default is Trial Time Step / 1000 if left blank.

Maximum Time Step

Field 6 of 2nd data block of AUTO STEP option. Blank by default. Marc default is Total Time / 2 if left blank.

Maximum # of Steps

Field 7 of 2nd data block of AUTO STEP option. Blank by default. Marc default is 10 X (Total Time / Trial Time Step Size) if left blank.

Total Time

Field 2 of 2nd data block of AUTO STEP option. Blank by default. Marc default is 1.0 if left blank.

Chapter 3: Running an Analysis 273 Load Step Creation

Adaptive Increment Parameter

Main Index

Description

# of Steps of Output

Field 1 of 3rd data block of AUTO STEP option. Blank by default. Marc default is 0 if left blank. Indicates that this many increments evenly spaced in time will be place in the output POST file. If left blank, the POST file settings dictate the increments written.

Quasi-static Inertial Damping Damping Energy Rate Damping Ratio

OFF by default. Places a 1 in 10th field of 2nd data block of AUTO STEP option if ON. Or places a 4 if Damping Energy Rate is ON. Damping must be defined in your material properties for this option to be effective in Marc Version 2001 (2003 and beyond, this is not necessary). The Damping Ratio is placed in the 9th field of the 3rd data block if Damping Energy Rate is ON. Turning these toggles ON can help in convergence for Static analysis by defining some artificial damping. Damping is based upon the estimated damping energy and the estimated total strain energy fromthe first increment of the Load Step.

Criteria

Multiple adaptive load stepping criteria is available. By default, none of this is necessary to define for Marc Version 2001 or greater. These criteria are described below in Adaptive Load Stepping Criteria, 274.

Time Integration Scheme

For Transient Dynamics, the Houbolt and Central Difference cannot be selected. Indicates the time integration scheme to use in dynamic analysis. The 2nd field of the DYNAMIC parameter is set to 2, 3, 4, 5, or 6 for Newmark, Houbolt, Central Difference, Fast Explicit, or Single Step respectively. Single Step Houbolt is the default when the Marc Version is 2000, otherwise it is Newmark. A lumped mass matrix is always used with Central Difference so the Lumped Mass Matrix parameter is ignored.

Time Integration Error Check

This turns on a Bergan check. For Transient Dynamics, this toggle is ON by default and writes a 1 to the 13th field of the 3rd data block of the AUTO STEP option. It is only applicable for Marc 2003 (r2) and beyond.

Note:

A one (1) is always be entered in the 9th field of the 2nd data block of AUTO STEP to invoke the enhanced scheme and thus, the reading of the 3rd data block. This feature is only invoked if the Marc Version is 2001 or greater.

Note:

The 8th field of the 2nd data block of the AUTO STEP option is the desired number of recycles (iterations) which is acquired from the Iteration Parameters (p. 240) form.

274 Marc Preference Guide Load Step Creation

Adaptive Load Stepping Criteria

These criteria are only required for the AUTO STEP option if the Marc Version=ás 2000 or less or the user desires to use them

Main Index

Chapter 3: Running an Analysis 275 Load Step Creation

K

Criteria

Main Index

Description

Treat Criteria as:

If Limits, sets 3rd field to zero (0) in 3rd data block (default). If Targets, sets field to one (1).

Use Automatic Criteria Continue if not Satisfied

If the first toggle is ON, then automatic physical criteria is used. The second toggle determines what happens if the criteria is not met. Field 12 of 3rd data block of AUTO STEP option. Both OFF by default.

Loading Table Instances

This pulldown determines how loading tables (Use Tables must be ON in the Job Parameters form) are treated by AUTO STEP. By default loads are increased or decreased such that they always Reach Peaks-Valleys Only. If you wish you can Reach All Points in Tables or Ingore all Points in Tables. Fields 10 and 11 of 3rd data block of AUTO STEP option.

Write Instances to Post File

If this toggle is ON, then the instances requested in the above pulldown menu for selecting Loading Table Instances are written to the Post file. This puts a 1 in the 11th field of the 3rd data block of AUTO STEP. Be careful using this because if ON, then only those instances are written to the POST file and not all the increments of the analysis.

Number of Cutbacks

Field 2 of 3rd data block of AUTO STEP option. Blank by default. Marc default is 10 if left blank or zero.

Ratio Between Steps:

For Smallest, sets 3rd field in 2nd data block (default = 0.1), For Largest, sets 4th field in 3rd data block (default=10.0).

Increment Criteria

Field 1 of 4th data block of AUTO STEP option. The 4th and 5th data blocks are repeated for every criteria selected. This places a 1, 2, 3, 4, 5, 7, 13 or 8, 9, 10, or 12 in this field based on Strain, Plastic Strain, Creep Strain, Normalized Creep Strain, Stress, Strain Energy, Temperature (Structural or Thermal/Coupled), Displacement, Rotation, or Normalized Stress, respectively. The labels “XXX Range” and “XXX Increment Allowed” will change based on the Increment Criteria selected. Note that for Transient Heat Transfer, only Temperature is valid to use.

Use Criterion

This will force the 4th and 5th data blocks to be written for this Criterion if ON. For a criteria to be used, this widget must be turned ON!

“Criterion” Range

This fills out fields 2, 4, and 6 of 5th data block of AUTO STEP option retrieved from the second column of data above. The first and last widgets are zero and 1e20 respectively and cannot change. The second and third must be the same as well as the 4th/5th and 6th/7th which define the ranges. The “Criterion” title changes according to the Increment Criterion chosen. Field 8 is always set to 1e20.

276 Marc Preference Guide Load Step Creation

Criteria

Description

“Criterion” Increment Allowed

This fills out fields 1, 3, 5, and 7 of 5th data block of AUTO STEP option. The “Criterion” title changes according to the Increment Criteria chosen.

Select a Group (optional)

You can optionally select a group of elements to which this criterion is to be applied. No group is selected by default. An Marc set is created and referenced in the 2nd field of the 4th data block.

Note:

Data blocks 4 and 5 are repeated for each criterion activated. If none are active, these data blocks are not written at all. Also note that the use of at least one criterion is required for Marc Versions less than 2001 when using AUTO STEP.

Note:

aata block 3, field 7 is always written as 1 for Static analysis, 2 for Trasient Dynamic analysis, and 3 for Creep analysis for Marc Version 2003 or greater when using AUTO STEP. This way a Static load step is not influenced by a subsequent Creep or Transient Dynamic step. And similarly for Creep and Transient Dynamics.

Adaptive Thermal

Solutions that have Adaptive Thermal load incrementation methods are Static (Structural & Coupled), Transient Dynamics (Coupled), Creep (Structural and Coupled), and Transient Heat. Static (Structural) uses the AUTO THERM option and all others use TRANSIENT option except Creep which uses AUTO THERM CREEP. For Static (Structural) this writes the AUTO THERM option according to this table:

Main Index

Chapter 3: Running an Analysis 277 Load Step Creation

Increment Parameter

Description

Maximum Temperature Change Allowed

1st field of 2nd data block of AUTO THERM option.

Maximum Time Step

5th field of 2nd data block

Total Transient Time

4th field of 2nd data block

Maximum # of Increments

2nd field of 2nd data block

Reassembly Interval

3rd field of 2nd data block

Scale to 1st Yield

Operates as it is currently implemented for Adaptive load incrementation.

For Static (Coupled), Transient Dynamics (Coupled), and Transient Heat Transfer, the Adaptive Thermal parameters are shown and described in Transient Heat Transfer, 259. For Creep analysis, these parameters appear directly on the Solution Parameters form and write the AUTO THERM CREEP option:

Main Index

278 Marc Preference Guide Load Step Creation

Increment Parameter

Description

Maximum Temperature Change

1st field of 2nd data block of the AUTO THERM CREEP option.

Total Transient Time

4th field of 2nd data block

Maximum # of Increments Allowed

2nd field of 2nd data block and 3rd field of 3rd data block

Suggested Time Increment

1st field of 3rd data block

Total Time

2nd field of 3rd data block

Creep Tests

5th field of 4th data block - 1 for absolute and 0 for relative.

Relative Strain Tolerance

1st field of 4th data block

Relative Stress Tolerance

2nd field of 4th data block

Low Stress Cut-off Tolerance

3rd field of 4th data block

Adaptive Creep

For Creep analysis, these parameters appear directly on the Solution Parameters form and write the AUTO CREEP option:

Main Index

Chapter 3: Running an Analysis 279 Load Step Creation

Parameter

Description

Increment Type

This is either Adaptive, Adaptive Creep, Adaptive Thermal or Fixed. Adaptive Creep causes an AUTO CREEP to be written the History section.

Suggested Time Increment

This time step size is entered into the 1st field of the 2nd data block of the AUTO CREEP option. This defaults to 1.0

Total Time

This is entered into the 2nd field of the 2nd data block of the AUTO CREEP option. The default is 100.0

Maximum # of Increments Allowed:

This is entered into the 3rd field of the 2nd data block of the AUTO CREEP option. The default is 50.

Creep Tests:

This is either Relative or Absolute. This affects the labels of the next two data fields and the defaults of the next three data fields. A one (1) is placed in the 5th field of the 3rd data block of the AUTO CREEP option if Absolute testing is to be used. Not necessary for Implicit Creep and should be hidden as well as the widgets below this.

Relative Strain Tolerance:

This is either the tolerance on the creep strain increment to the elastic strain (Relative) or the absolute tolerance on the creep strain. The “Relative” in the label is removed if Absolute. The defaults are 0.5 or 0.01 respectively. This is placed on the 1st field of the 3rd data block of the AUTO CREEP option.

Relative Stress Tolerance:

This is either the tolerance on the stress increment to the stress (Relative) or the absolute tolerance on the creep stress. The “Relative” in the label is removed if Absolute. The defaults are 0.1 or 100.0 respectively. This is placed on the 2nd field of the 3rd data block of the AUTO CREEP option.

Low Stress Cut-off Tolerance:

This is the tolerance on the low stress cut-off point. Points lower than this ratio relative to the maximum stress are not used in creep tolerance checking. The default is 0.05. This is placed on the 3rd field of the 3rd data block of the AUTO CREEP option.

Fixed Load Incrementation

This form varies slightly between Statics (Structural), Transient Dynamics and Creep. The differences are noted below. For Static (Coupled) and Transient Heat Transfer, the Fixed parameters are shown and described in Transient Heat Transfer, 259. For Statics (Structural), the AUTO LOAD and/or the TIME STEP options are generated depending on whether the load case is time dependent or not. Only Fixed is available for Linear Statics and is the default. Transient Dynamics uses the DYNAMIC CHANGE option. And Creep uses the CREEP INCREMENT plus the AUTO LOAD option.

Main Index

280 Marc Preference Guide Load Step Creation

Note:

Main Index

Different usage scenarios can result depending on whether static or time dependent loading is used. These are outlined in Usage Scenarios, 282.

Chapter 3: Running an Analysis 281 Load Step Creation

Fixed Increment Parameter

Description

Automatic Cutback

Applies to Nonlinear Statics only. This is a feature for Marc 2000 and above. It is ignored if the Marc Version is K7. It is ON by default. If an increment does not converge, it allows for a restart from the last increment cuts the increment size in half. This writes the RESTART LAST option to the input file with a one (1) in the 1st field of the 2nd data block. Marc automatically handles the restart from the last increment.

Number of Cutbacks

This is associated with Automatic Cutback. It writes the integer number (defaulted to 3) to the 3rd field of the AUTO LOAD option. This parameter determines how many times a cutback is allowed.

Number of Increments or Number of Steps

For Statics and Creep this is the number of increments specified in the AUTO LOAD option in the 1st field of the 2nd data block. Or for Transient Dynamics defines the number of steps to use throughout the analysis for Fixed time step type. This is entered in the 3rd field of the 2nd data block of the DYNAMIC CHANGE option. Note the label change. Default is 10.

Total Time

For Statics, this enters the TIME STEP option which is the total time as defined in this widget divided by the number of increments. For Transient Dynamics this is the 2nd field of the 2nd data block of the DYNAMIC CHANGE option. Default is blank. The 1st field is determined by total time / number of steps. If left blank the total time placed here is determined from the dynamic load defined in the field. For Creep, the total time is either placed in the 2nd data block of a CREEP INCREMENT option or the total time is divided by the Number of Increments, if this value is present, and the incremental time is written to the 2nd data block of the CREEP INCREMENT option.

Scale to 1st Yield

Main Index

This puts a SCALE parameter in the input deck. It is a flag to force the first increment (increment zero) to take the load up to the yield point. This requires that the load options be placed in the Model Definition section. This parameter is not written to the input file for time dependent load cases and it only affects the first Load Step selected. Subsequent Load Steps ignore this if it is ON. It also requires that the Number of Increments be specified. In the first Load Step after the END OPTION it places the AUTO LOAD and also the PROPORTIONAL INCREMENT. The 1st field is set to zero (0) and the second field is set to the reciprocal of the Number of Increments. This is only valid for Small Displacement/Strain and Nonlinear Statics only.

282 Marc Preference Guide Load Step Creation

Fixed Increment Parameter

Description

Fraction of Scaled Load

This places the PROPORTIONAL INCREMENT in the History section of the input deck and is used in conjunction with SCALE. The load is scaled to first yield. The load increments thereafter are a percentage of this load.

Eigenvalue Extractions

Modal or Buckling extractions can be done at specified increments for Linear or Nonlinear Statics. They are both OFF by default. Only one or the other can be ON, but not both. A DYNAMIC or BUCKLE parameter is written if ON.

List of Increments for Extraction

This is a list of increments for which the analysis will be postponed for an eigenvalue extraction analysis. This places a MODAL INCREMENT or a BUCKLE INCREMENT in the Model Definition of the input file. The list is placed in the 3rd or 4th data blocks respectively.

Eigenvalue Extract Parameters

This brings up a subordinate form for selecting the eigenvalue extraction parameters. This form is identical to that for Normal Modes or Buckling solution parameter forms. For Modal Eigenvalue Extraction, see Normal Modes, 238. For Buckling Eigenvalue Extraction see Buckling, 240.

Gamma / Beta

For Transient Dynamics only, fields 7 and 8 of the 2nd data block of the DYNAMIC CHANGE option. Default is 0.5.

Time Integration Scheme

For Transient Dynamics, same description as above for Adaptive load stepping.

Fractions of Critical Damping

For Linear Modal Transient Dynamics, defines the damping for each mode as a fraction of the critical damping. This is a list and contains fractions for all of the modes requested in the Extraction Parameters form, starting with the first mode. Its contents is entered in the 2nd data block of the DAMPING option. If only one value is supplied, all modes take on this value. If not enough values are given, extra modes are assigned the last value in the list. Extra values are ignored. Default is 0.05.

OK

Closes form and saves set information.

Defaults

Set the form back to its defaults.

Cancel

Closes form and does not save changed information.

Usage Scenarios

The major differences in using Fixed or Adaptive load/time stepping versus static or time dependent loads are illustrated in the following tables. To relate these tables to Transient Dynamics, replace the

Main Index

Chapter 3: Running an Analysis 283 Load Step Creation

AUTO LOAD/TIME STEP combination with DYNAMIC CHANGE and the AUTO INCRMENT with AUTO STEP: Static Load Case - Fixed Load Stepping # of Increme nts blank

Total Time blank

Scale OFF

Remarks • Ignores fields associated to LBCs. • Places no AUTO LOAD or TIME STEP options in input file. • Loads are placed in History section with initial displacements

set to zero in Model Definition section. • Eigenvalue extraction in this case would only occur after

increment one. supplied

blank

OFF

• Ignores fields associated to LBCs. • Places AUTO LOAD before loads in History section with

initial displacements set to zero in Model Definition section. • No TIME STEP option written. • Loads are written as total loads using FOLLOW FOR, -1, 1

parameter. blank

supplied

OFF

• Ignores fields associated to LBCs. • Places TIME STEP in History section with initial

displacements set to zero in Model Definition section. • No AUTO LOAD option written.

supplied

supplied

OFF

• Ignores fields associated to LBCs. • Places AUTO LOAD before loads and TIME STEP in

History section with initial displacements set to zero in Model Definition section. • Loads are written as total loads using FOLLOW FOR, -1, 1

parameter. supplied or blank

supplied of blank

ON

• Places SCALE and PROPORTIONAL INCREMENT in

History section. • Is only valid when - 1. Nonlinear Statics, 2. Small

Strains/Displacements, 3. Static load case, 4. First Load Step only. Otherwise no SCALE or PROPORTIONAL INCREMENT is written. • If number of increments or total time is supplied they are

written as indicated by the above cases.

Main Index

284 Marc Preference Guide Load Step Creation

Static Load Case - Adaptive Load Stepping # of Increme nts not applicab le (n/a)

Total Time blank

Scale OFF

Remarks • Places AUTO INCREMENT (or AUTO STEP) before loads

in History section with initial displacements set to zero in Model Definition section. • Total time defaults to one (1). • Loads are written as total loads.

n/a

supplied

OFF

• Places AUTO INCREMENT (or AUTO STEP) before loads

in History section with initial displacements set to zero in Model Definition section. • Total time written to AUTO INCREMENT or AUTO STEP

as supplied. • Loads are written as total loads.

n/a

supplied or blank

ON

• Places SCALE in Parameter section if in 1st load step only. • AUTO INCRMENT (or AUTO STEP) is placed in History

section as explained for the above two cases.

Note:

Main Index

You cannot mix static and time dependent load cases - All Load Steps must have either all static or all time dependent load cases.

Chapter 3: Running an Analysis 285 Load Step Creation

Time Dependent Load Case - Fixed Load Stepping # of Increme nts blank

Total Time blank

Scale OFF

Remarks • If there is no field associated to an LBC, values are treated as if

they were first point of a field. If none have a field they are treated like the similar static case. • A discrete time step exists between each point in the field.

Loads are placed between CONTINUE options in the History section with no AUTO LOAD written. • Field definitions automatically include time. TIME STEP is

written for time value between each point in field. • LBCs from first point are placed in Model Definition for first

Load Step. • Loads are total loads and the FOLLOW FOR, -1, 1 parameter

is written. supplied

blank

OFF

• Identical to the above case except an AUTO LOAD is written

before loads for each point in the field with the number of increments specified. • Loads are total loads and the FOLLOW FOR, -1, 1 parameter

is written. blank

supplied

OFF

• Identical to the first case of time dependent loading except the

signal can be truncated if the total time is not greater than or equal to the length of the field. • Only writes out the number of points up to and including the

ending time point. No AUTO LOAD is place in deck. The following scenarios exist: • 1. Total time is less than time in field: points below the total

time are written. The last point is interpolated. • 2. Total time is greater than or equal to time in field - only

points up to the last point in field are written. supplied

supplied

OFF

• A combination of the above two cases. • AUTO LOAD written for each time step. • Signal truncated if total time is less than total time of signal as

explained above. supplied or blank

Main Index

supplied of blank

ON

• Will be ignored - no SCALE or PROPORTIONAL

INCREMENT will be written. Otherwise behaves as above examples for time dependent loading.

286 Marc Preference Guide Load Step Creation

Time Dependent Load Case - Adaptive Load Stepping # of Increme nts n/a

Total Time blank

Scale OFF

Remarks • If there is no field associated to an LBC, values are treated as if

they were first point of a field. If none have a field they are treated like the similar static case. • A discrete time step exists between each point in the field.

Loads are placed between CONTINUE options in the History section with an AUTO INCREMENT written. • Field definitions automatically include time. The time between

each point is written as the total time to the AUTO INCREMENT for those two points. • LBCs from first point are placed in Model Definition for first

Load Step. • Loads are total loads and complete signal is written.

n/a

supplied

OFF

• Identical to the above case except the total time specified can

truncate the signal that is written. The following scenarios exist: • 1. Total time is less than time in field: points below the total

time are written. The last point is interpolated. • 2. Total time is greater than or equal to time in field - only

points up to the last point in field are written. n/a

supplied of blank

ON

• Will be ignored - no SCALE will be written. Otherwise

behaves as above examples for time dependent loading and adaptive load stepping.

And the following scenarios exist for multiple Load Steps:

Main Index

Chapter 3: Running an Analysis 287 Load Step Creation

:

Static Load Case - Multiple Load Steps - Fixed or Adaptive Load Stepping # of Increme nts

Total Time

blank or supplied

blank or supplied

Scale OFF

Remarks • First Load Step is written as per the cases explained above for

static loads • The time step for the first point of the second Load Step is

determined by the time of the first point minus the time of the last point from the previous Load Step. • The time of the first point of the field associated with the

second Load Step must be greater than the time of the last point of the field associated with the first Load Step, otherwise an error will occur. • Otherwise, rules from above cases apply. • In this scenario, each LBC can be associated to a single field or

different fields as long at the total cumulative time of all previous Load Steps is present in the LBCs of interest for the current Load Step. Time Dependent Load Case - Multiple Load Steps - Fixed or Adaptive Load Stepping # of Increme nts

Total Time

blank or supplied

blank or supplied

Scale OFF

Remarks • First Load Step is written as per the cases explained above for

time dependent loads. • The total time from all previous Load Steps is cumulative. • The time at which you start the new Load Step must be present

in the field, otherwise an error will occur. • The time at which you start the new step is the total time from

the previous steps. • Otherwise, rules from above scenarios apply. • In this scenario, each LBC associated to each Load Step must

reference the same fields. This scenario is used for breaking time dependent fields into various Load Steps. Iteration Parameters This subordinate form appears when the Iteration Parameters button is selected on the Static, Transient Dynamics, Creep, or Heat Transfer solution parameter forms.

Main Index

288 Marc Preference Guide Load Step Creation

Iteration Parameter

Main Index

Description

Proceed if not Converged

Forces the analysis to proceed even if the increment did not converge. This writes a negative number to the 2nd field of the 2nd data block of the CONTROL option. Actual number placed there is controlled in the Iteration Parameters form.

Non-positive Definite

This forces the non-positive definite flag ON in the 3rd field of the SOLVER option. A new SOLVER option is written for each step if a change in this flag has been detected from Load Step to Load Step.

Chapter 3: Running an Analysis 289 Load Step Creation

Iteration Parameter

Main Index

Description

Initial Stress Stiffness

This can be set to Full, None, Tensile, Deviatoric, and Begin Increment. This allows for initial stress to contribute to the stiffness as a normal-full contribution, as no contribution at all, using only positive stresses, by reducing hydrostatic pressure contribution for Mooney material, or by using contribution of stress at the beginning of the increment and not the last iteration, respectively. This is entered in the 10th data field on the 2nd data block of the CONTROL option. Values are 0, 2, 4, 1, and 3, respectively. Full is default.

Iteration Method

Indicates the iteration method to be used. This is can be set to Full Newton-Raphson, Modified Newton-Raphson, NewtonRaphson with Strain Correction, or Secant Method. This is entered in the 6th data field on the 2nd data block of the CONTROL option. Values are 1, 2, 3, and 4 respectively. Full Newton-Raphson is default.

Max # of Iterations per Increment

Defines the maximum number of iterations allowed for convergence in any increment. This is entered in the second data field on the second card of the CONTROL option. This number is negative if Proceed if not Converged is ON from the Solution Parameter form. For a Creep analysis, this is also placed on the 4 field of the 2nd data block of the AUTO CREEP if Adaptive time step incrementing is used. For Heat Transfer, this is placed on the 2nd field of the 2nd data block.

Minimum # of Iterations per Increment

This is the 3rd field of the 2nd data block of the CONTROL option. It can be an integer number zero or greater. If this is set greater than zero, every increment will perform at least this many iterations.

Desired # of Iterations per Increment

Defines the number of desired iterations in an increment which is placed on the AUTO INCREMENT option in field 3 of data block 2 or the 8th field of the 2nd data block of the AUTO STEP option. If the actual number of iterations is less than this value, this will be used to figure out how much to increase the load step for the next increment. In a similar manner if the actual number of iterations is greater than this number (but less than the Max # of Iterations per Increment, this will be used to decrease the load step in the next increment. Obviously if Adaptive incrementation is not specified, this data will not be used.

Tolerance Method

Defines the tolerance method to be used. This can be set to Residual, Incremental Displacement, or Incremental Strain Energy. It is entered as the 4th field on the 2nd data block of the CONTROL option, zero (0), one (1), or two (2) respectively.

290 Marc Preference Guide Load Step Creation

Iteration Parameter Residuals/Displacements And Or

If you want the Tolerance Method to use both Residuals and Displacements to determine convergence set this to And. If you want either one or the other to determine convergence, set this to OR. If Tolerance Method is set to Residual or Displacement, then these two toggles are enabled. Both are OFF by default. If one is ON, the other is OFF. These toggles work in combination with Tolerance Method in setting the 4th field of the 2nd data block of the CONTROL option. If And is ON, then a five (5) is written. If Or is ON, then a four (4) is written. If both are OFF, then Tolerance Method determines what is written.

Error Type

Indicates the type of error to use. This can be set to Relative or Absolute or Both, and is entered in the 5th data field on the 2nd data block of the CONTROL option, zero (0) or one (1) or two (2) respectively.

Automatic Switching

This controls automatic switching between Residuals and Displacement tolerances if one or the other fails to converge. If this is ON (default), then one (1) is written to the 11th field of the 2nd data block which is currently done now. If this is OFF, then a zero is written. Also if the Error Type is anything but Relative, a zero (0) is written.

Residual Tolerances

Values and labels in this frame depend on the Tolerance Method and Error Type setting and are discussed below.

Relative Residual Force

The value of this widget (default is 0.1) is written to the 1st field of the 3rd data block of the CONTROL option. If the And or the Or toggles are ON, then the Relative Residual Force is written to data block 3 and the Relative Displacement is written to data block 3a (same field).

Relative Displacement Relative Energy

Main Index

Description

Relative Residual Moment Relative Rotation

The value of this widget (default is 0.0) is written to the 2nd field of the 3rd data block of the CONTROL option. If the And or the Or toggles are ON, then the Relative Residual Moment is written to data block 3 and the Relative Rotation is written to data block 3a (same field).

Minimum Reaction Force Minimum Displacement

The value of this widget (default is blank) is written to the 3rd field of the 3rd data block of the CONTROL option. If the And or the Or toggles are ON, then the Minimum Reaction Force is written to data block 3 and the Minimum Displacement is written to data block 3a (same field).

Chapter 3: Running an Analysis 291 Load Step Creation

Iteration Parameter

Description

Minimum Reaction Moment Minimum Rotation

The value of this widget (default is blank) is written to the 4th field of the 3rd data block of the CONTROL option. If the And or the Or toggles are ON, then the Minimum Reaction Moment is written to data block 3 and the Minimum Rotation is written to data block 3a (same field).

Maximum Residual Force Maximum Displacement

The value of this widget (default is 0.1) is written to the 5th field of the 3rd data block of the CONTROL option. If the And or the Or toggles are ON, then the Maximum Residual Force is written to data block 3 and the Maximum Displacement is written to data block 3a (same field).

Maximum Residual Moment Maximum Rotation

The value of this widget (default is 0.1) is written to the 6th field of the 3rd data block of the CONTROL option. If the And or the Or toggles are ON, then the Maximum Residual Moment is written to data block 3 and the Maximum Rotation is written to data block 3a (same field).

Contact Table A contact table is used to control the behavior of and to activate or deactivate, or in some cases, remove contact bodies from the analysis. Contact bodies can be controlled from Load Step to Load Step using the contact table. The form is shown below with a table describing the options.

Main Index

292 Marc Preference Guide Load Step Creation

Note:

After entering the data in any of the data boxes, the ENTER key must be pressed in order to save the value.

Data from this table fills out the 3rd data block of the CONTACT TABLE option.

Main Index

Chapter 3: Running an Analysis 293 Load Step Creation

Contact Parameter Global Contact Detection There are two Contact Detection widgets on the form. This option menu sets all contact pairs globally. The other switch allows you to define the contact detection individually per contact pair.

Description Marc 2001 and beyond allows for a non-symmetric contact table. What this really means is that you can specify the order in which the contact checking is done. Note that if multiple cells are selected, only those cells are affected. If none or only one cell is selected, this option affects the entire contact table. The options are: • Default (by body #) - places a 0 in the 8th field of the 3rd data

block. This is the default where contact is checked in the order the bodies are written to the input deck. In this scenario, the most finely meshed bodies should be listed first. There will be contact checks first for nodes of the first body with respect to the second body and then for nodes of the second body with respect to the first body. If Single Sided contact is activated in Contact Parameters, 191, then only the first check is done. • Automatic - places a 2 in the 8th field of the 3rd data block.

Unlike the default, the contact detection is automatically determined and is not dependent on the order they are listed but determined by ordering the bodies starting with those having the smallest edge length. Then there will be only a check on contact for nodes of the first body with respect to the second body and not the other way around. • First ->Second - places a 1 in the 8th field of the 3rd data block

and also blanks the lower triangular section of the table matrix such that no input can be accepted. Only the contact bodies from the upper portion are written, which forces the contact check of the first body with respect to the second body. • Second-> First - places a 1 in the 8th field of the 3rd data block

and also blanks the upper triangular section of the table matrix such that no input can be accepted. Only the contact bodies from the lower portion are written. Contact detection is done opposite of First->Second. • Double-Sided - places a 1 in the 8th field of 3rd data block and

writes both upper and lower portions of the table matrix. This overrules the Single Sided contact parameter set in Contact Parameters, 191.

Main Index

Touch All

Places a T to indicate touching status for all deformable-deformable or rigid-deformable bodies. Note that if multiple cells are selected, only those cells get set to Touch.

Glue All

Places a G to indicate glued status for all deformable-deformable or rigid-deformable bodies. Note that if multiple cells are selected, only those cells get set to Glue.

294 Marc Preference Guide Load Step Creation

Contact Parameter

Description

Deactivate All

Blanks the spreadsheet cells. Note that if multiple cells are selected, only those cells are deactivated.

Import/Export

Import or export the contact table to/from a csv (comma delimited) file. This file can be opened and modified in Excel. All visible cells in the contact table are imported/exported plus two additional items: The release status Yes or No: If Yes, a 0 or 1 for immediate or gradual force removal is appended, e.g., Yes-0 or Yes-1 The contact status is specified for each pair: Touch, Glue or Inactive with DFLT, AUTO, DBLE, FRST, SCND appended, e.g. Touch-DFLT, Glue-SCND No other properties are currently imported/exported to/from the spreadsheet. If you modify the spreadsheet, make sure you use exactly the same nomenclature as above with no spaces or unpredictable things may result. The i,j entry must be the same as the j,i entry for the contact status (DFLT,AUTO,DBLE,FRST,SCND).

Main Index

Select Existing

Select a contact table from an existing Load Step. The contact table will be populated with the parameters from the existing Load Step. The selected Load Step must be associated to the same load case or the operation will not be allowed.

Contact Matrix

The spread sheet that appears lists all deformable bodies (first) followed by rigid bodies. Only the bodies included in the load case associated to this particular Load Step are listed. The individual cells can be clicked with the mouse/cursor to change their values from Touching, Glued, or no contact (blank).

Body Type

Lists the body type for each body; either deformable or rigid.

Release

This cell can be toggled by clicking on the cell for each body to Y or N (yes or no). If Y, this indicates that the particular contact body is to be removed from this Load Step. This writes the RELEASE option to the History section. The forces associated with this body can be removed immediately in the first increment or gradually over the entire Load Step with the Force Removal switch described below. Note that if multiple cells are selected in this column, the first cell’s value is filled down to the rest of the selection.

Chapter 3: Running an Analysis 295 Load Step Creation

Contact Parameter Touching Body Touched Body

Description These are informational or convenience list boxes to allow you to see which bodies an active cell references and to see what settings are active for Distance Tolerance and other related parameters below. You must click on the touched/touching bodies to see what values, if any, have been set for the pair combination. Note:

Main Index

For all properties of contact pair listed below, if multiple cells are selected in the spreadsheet, then properties are set for the entire selection.

Retain Gaps/Overlaps

This is only applicable for the Glued option. Any initial gap or overlap between the node and the contacted body will not be removed (otherwise the node is projected onto the body which is the default). For deformable-deformable contact only, and if the Marc Version is 2001 or greater this places a 2.0 in field 7 of 3rd data block if ON, otherwise places a 1.0 in same field.

Stress-free Initial Contact

This is only applicable for initial contact in increment zero, where coordinates of nodes in contact can be adapted such that they cause stress-free initial contact. This is important if, due to inaccuracies during mesh generation, there is a small gap/overlap between a node and the contacted element edge/face. For deformable-deformable contact only, and if the Marc Version is 2001 or greater this places a 1 in the 9th field of the 3rd data block. If both this and Delayed Slide Off are on, this places a 3 in the 9th field instead.

Delayed Slide Off

By default, at sharp corners, a node will slide off a contacted segment as soon as it passes the corner by a distance greater than the contact error tolerance. This extends this tangential tolerance. For deformable-deformable contact only, and if the Marc Version is 2001 or greater this places a 2 in the 9th field of the 3rd data block. If both this and Stress-free Initial Contact are on, this places a 3 in the 9th field instead.

Allow Separation

If glued contact is set for the contact pair, then this toggle can be set to allow separation if the Separation Force exceeds the given amount. This places a 1in the 10th field of the 3rd data block of the CONTACT TABLE option if ON.

296 Marc Preference Guide Load Step Creation

Contact Parameter Force Removal

Description If any of the contact bodies have been flagged for release in this Load Step then a RELEASE option is written to the end of the Load Step in question referencing the bodies that are turned on in the 2nd data block of the RELEASE option. The switch for Immediate or Gradual Force Removal in the Load Step is placed as 0 or 1 respectively, in the RELEASE option in the 2nd field of the 1st data block. Immediate will remove the load in the first increment. Gradual will remove the load gradually over the entire Load Step.

Structural Properties:

Main Index

Distance Tolerance Near Contact Dist Tolerance

Set the Distance Tolerance for this pair of contact bodies. This is the 2nd field of the 3rd data block. A nonspatial field can be reference for Marc Version 2003 or greater that will write this data in TABLE format, if this parameter varies with time, temperature, or some other independent variable. This overrides any other settings for Distance Tolerance. Near Contact Dist. Tol. is for thermal contact analysis.

Bias Tolerance

Set the Bias Tolerance for this pair of contact bodies. This is the 5th field of the 4th data block. This overrides any other settings for Bias Tolerance. For a description of this parameter, see Contact Detection, 193.

Separation Threshold

Set the Separation Threshold for this pair of contact bodies. This can be a force or a stress depending on the option set for contact separation. This is the 1st field of the 4th data block in V10 format. A field can be reference for Marc Version 2003 or greater that will write this data in TABLE format, if this parameter varies with time, temperature, or some other independent variable. This overrides any other settings for Separation Force.

Friction Coefficient

Set the Friction Coefficient for this pair of contact bodies. This is the 2nd field of the 4th data block in V10 format. A field can be reference for Marc Version 2003 or greater that will write this data in TABLE format, if this parameter varies with time, temperature, or some other independent variable. This overrides any other settings for Friction Coefficient.

Interference Closure

Set the Interference Closure for this pair of contact bodies. This is the 3rd field of the 4th data block in V10 format. A field can be reference for Marc Version 2003 or greater that will write this data in TABLE format, if this parameter varies with time, temperature, or some other independent variable. This overrides any other settings for Interference Closure.

Chapter 3: Running an Analysis 297 Load Step Creation

Contact Parameter

Description

Hard-Soft Ratio

Set the Hard-Soft Ratio for this pair of contact bodies. This is the 7th field of the 4th data block in V10 format. Default is 2 if not specified. This overrides any other settings for Interference Closure. This parameter is only used if double-sided contact with automatic constraint optimization is used. The hard-soft ratio can be used by the program if there is a significant difference in the (average) stiffness of the contact bodies (expressed by the trace of the initial stress-strain law). If the ratio of the stiffnesses is larger than the hard-soft ratio, the nodes of the softest body are the preferred slave nodes.

Friction Stress Limit

Set the Friction Stress Limit for this pair of contact bodies. This is the 4th field of the 4th data block in V10 format. A field can be reference for Marc Version 2005 or greater that will write this data in TABLE format, if this parameter varies with time, temperature, or some other independent variable. The default is 1e20. This value can be used together with Coulomb friction according to the bilinear displacement based model. If the shear stress due to friction reaches this limit value, the applied friction force is reduced, so that the maximum friction stress is given by where is the friction coefficient, is the normal stress, is the limit stress. min ( μ X σn, σl) where μ is the friction coefficient, σn is the normal stress, σl is the limit stress.

Delayed Slide Off Length

Set the Delayed Slide Off Length for this pair of contact bodies. This is the 6th field of the 4th data block in V10 format. This entry is only used if Delayed Slide Off has been activated. When using the delayed slide off option, a node sliding on a segment will slide off this segment only if it passes the node (2-D) or edge (3-D) at a sharp corner over a distance larger than the delayed Slide Off Distance. By default, the delayed slide off distance is related to the dimensions of the contacted segment by a 20 percent increase of its isoparametric domain if not specified otherwise.

Thermal Properties: Heat Transfer Coefficient Near Contact Heat Trf Coeff Natural Convection Coef. Natural Convection Exp. Surface Emissivity Distance Dep. Conv. Coeff.

Main Index

Set the thermal heat transfer properties for this pair of contact bodies. These are the 1st - 6th fields of the 5th data block in V10 format. A field can be reference for Marc Version 2003 or greater that will write this data in TABLE format, if this parameter varies with time, temperature, or some other independent variable. This overrides any other settings. This is only used in Thermal or Coupled analysis.

298 Marc Preference Guide Load Step Creation

Contact Parameter

Description

Electrical Properties: Contact Conductivity Near Contact Conductivity Distance Dep Conductivity

Sets the electrical properties for this pair of contact bodies. These are the 1st - 3rd fields of the 9th data block. Used for Joule Heating only and supports only the TABLE format. A field can be reference if this parameter varies with time, temperature, or some other independent variable. This overrides any other settings. This is only used in Coupled analysis.

OK Defaults

OK saves the spreadsheet as set by the user to this point and closes the form. Cancel will reset the form back to it’s original state prior to opening the form or saving the contact table and closes the form. Defaults will set the contact table and all properties to their defaults.

Cancel

Notes about Contact Tables

Using a contact table is very powerful, but needs some explanation such that you understand how Marc deals with contact bodies and contact tables. The contact table allows you to activate and deactivate contact bodies from Load Step to Load Step. But it is not quite as simple as simply adding or removing contact bodies from a load step to make them active or inactive. For example, contacting nodes encountered when a contact body is active are prevented from penetrating a body. However contacting nodes encountered relative to an inactive body are allowed to penetrate (as if it were not there), but if the body is made active again, penetrated nodes are ignored unless they are within the contact tolerance zone. Thus it is possible for a contact body to engage some nodes along a contact surface while ignoring others on the same surface it passed when it was inactive because the motion of the contact body is not controlled by the contact table (in other word, motion may still occur eventhough the contact body is inactive). The following recommendation are made when complex contact body interactions require contact table definitions to control: 1. It is important to understand that defined motion control of rigid bodies continues from Load Step to Load Step regardless of whether they are active or inactive (not in the contact table). The contact table only determines contact detection. Thus: 2. Put all contact bodies in all load cases (and thus contact tables) referenced by the jobs Load Steps. Remove them from the contact table (or load case) only when they are no longer needed in the problem at all. And even then, you should use the Release option first (in a previous step) before removing them completely. 3. Control rigid body motion in a single direction using scale factors (in load cases) if you can. If you want a velocity driven body to stop, keep it in the load case but give it a zero scale factor. You can reverse the motion of a velocity driven rigid body using a (-1) scale factor. In fact you can control any motion in a single direction easily over multiple steps using scale factors. 4. For contact that must have independent motion in multiple directions of a single body you must use a 2D field. Or you can create independent bodies for each direction and replace the first with the another using the contact table, but this is clumsy and prone to error.

Main Index

Chapter 3: Running an Analysis 299 Load Step Creation

Note:

It is always good practice to check and possibly rebuild your contact table if you make any changes to your contact definitions after you have created a Load Step. The contact table from the first Load Step is always written to the Model Definition section of the input deck also.

For full visualization of the contact table, you can turn the below indicated toggle ON. The size of the visible table can also be increased or decreased (dependent on the resolution of the monitor).

Main Index

300 Marc Preference Guide Load Step Creation

Active/Deactive Elements

Active/Deactive Group

Main Index

Description for Patran Groups

Group of Element to Deactivate

Lists all groups. Elements in the selected group will be deactivated.

Group of Elements to Activate

Lists all groups. Elements in the selected group will be activated.

OK

Closes the form and saves the selections.

Defaults

Deselects all groups in both list boxes.

Cancel

Closes the form and does not save any changes.

Chapter 3: Running an Analysis 301 Load Step Creation

Note:

Groups selected here must follow the same naming convention of 10 unique characters as described in Groups to Sets, 201.

In addition to

Main Index

302 Marc Preference Guide Load Step Creation

Metal Cutting

Description for Metal Cutting

Cutting File

Lists all files of File Type in current directory.

File Type:

Can be a Cutter path file with extension.CCL file or APT

[Rapid Motion Speed]

Optional cutter speed. If no value is provided, the speed of the rapid cutter motion is the same as the regular cutting speed of the cutter.

[Rigid Body Name]

Optional rigid body name if you wish to visualize the cutter path during postprocessing. The rigid body must be placed at the initial location of the cutting.

Adapt Each Increment Adapt Last Increment

If local adaptive meshing is selected with method Element in Cutter Path, then adaptation will occur at the end of each increment or at the end of the Load Step based on this setting.

Time Synchronization

If ON, then time synchronization is needed between the time defined by the Load Step and the real calculated time based on cutter motion in the APT/CCL file. If ON, a factor is applied to the calculated time based on cutter motion.

Pre State Options Temperature Loading, Axisymmetric to 3D, Pre State, Structural Zooming Options

Main Index

Chapter 3: Running an Analysis 303 Load Step Creation

This option is used to specify usage of a previously generated Marc POST (results) file containing results to be mapped to the current analysis. These results can be temperatures generated from a previous Heat Transfer analysis, results from an axisymmetric, plane strain, or similar analysis for mapping initial conditions onto a 3D model generated from the previous model, or results converted to boundary conditions for a structural zooming (global to local) analysis. The post file selected here is specified when submitting the analysis via a parameter on the submit line: run_marc -j jobname -pid postfile

The widgets to each of these are explained below. Note:

Main Index

Although it is possible to select a different POST file for each Load Step created, only the selected POST file of the first encountered Load Step is used.

304 Marc Preference Guide Load Step Creation

Temperature Loading

To use this option, a previous Heat Transfer analysis must have been run and the POST (results) file saved, containing temperatures. Marc will map the temperatures onto the new model. The same mesh need not be used, but it is recommended that the mesh be the same. This will write options with the appropriate INITIAL STATE, CHANGE STATE keywords. If both a results file is selected and the thermal loads defined within Patran, the latter will be ignored. Temperature Parameter Initial Increment Number

For Structural analysis, this is the 5th field of the 2nd data block of the INITIAL STATE history option and defines the increment number to read from the POST file to define initial temperatures. If this is left blank, no INITIAL STATE is written from this option. It must also be defined in the first referenced Load Step to actually be written. If a value is supplied, this will override the INITIAL STATE of any Reference Temperature defined in a Material property. Note that Nodal LBC Tempeartures (POINT TEMP) are incompatible with INITIAL STATE and should not be defined if this option is being used. For Thermal or Coupled analysis, the INITIAL TEMPERATURE option is written and overrides any LBC defined Initial Temperatures.

Start Increment Number

This is the 5th field of the 2nd data block of the CHANGE STATE history option. This is only available for Structural analysis and defines the increment number on the POST file to begin reading temperature results. If the Number of Incremetns to read is zero or less, then CHANGE STATE is not written.

Number of Increments

This is the 6th field of the 2nd data block of the CHANGE STATE history and defines how many increments to read from the POST file for Fixed and Adaptive Thermal load increment procedures (AUTO LOAD, AUTO THERM, AUTO THERM CREEP). In these cases, a one-to-one correspondence of load increments to termal increments on the POST file is used. For the default Adaptive (AUTO STEP) procedure this value is ignored and the actual corresponding time values are used. This is only available for Structural analysis. If this value is zero or less, no CHANGE STATE is written.

Select File

This is Binary (default) or Text. Places a 24 or 25 in the 4th field of the 2nd data block of the INITIAL/CHANGE STATE options. The file is either a .t16 for binary or a .t19 for text. This is determined automatically depending on which file you select.

Note:

Main Index

Description

The 1st field of the 2nd data block of the CHANGE STATE history option is always set to one (1) to indicate temperatures for this capability. Also, only one temperature results file can be specified for all Load Steps. Most other parameters can change from Load Step to Load Step however.

Chapter 3: Running an Analysis 305 Load Step Creation

Axisymmetric to 3D, Plane Strain to 3D, 2D to 2D, 3D to 3D

To perform an axisymmetric to 3D or a Plane Strain to 3D analysis, the following must be done: 1. Run an axisymmetric or p lane strain analysis and save the resulting POST (results) file. 2. Rezone the elements based on the displacement results of the last increment (or the increment of interest) of the axisymmetric analysis (optional). 3. Sweep the elements to create the full 3D model. 4. Apply loads and boundary conditions, assign element and material properties to the new 3D model. 5. Set up and submit the job indicating the results file to use for defining initial conditions of the new 3D analysis. The same is done for 2D to 2D or 3D to 3D analysis except step 3 is skipped and the new model is the same dimension as the previous model. Marc will map the results from the previous analysis to the new analysis model automatically. For 2D to 3D, the rezone and sweep steps above (2 & 3) can be accomplished in a single operation in Patran (or MSC.AFEA) under the Finite Element (FEM) application using the Sweep | Element | options. The displacement results to rezone the 2D mesh are selected under the FE Parameters... button on this FEM application form. The widgets on this form comprise the data needed for the AXITO3D or PRE STATE option as explained below. Note that PRE STATE is always written for Marc version 2005 or greater even if Axisymmetric to 3d is selected. If Marc 2003, only AXITO3D is supported. Parameter

Main Index

Description

Stress Total Equivalent Plastic Strain Temperature Strain Plastic Strain Thermal Strain Creep Strain Equivalent Creep Strain Displacements

All of these toggles are OFF by default. If they are ON, they place a one (1) in fields 7 through 15 or the 2nd data block of the AXITO3D or PRE STATE option, respectively. Otherwise a zero (0) is entered. At least one of them must be ON before the job is submitted. If Displacements are selected, there is no need to rezone the model. If Displacements are not selected, Marc assumes the initial mesh configuration to be in the deformed position at the last increment of the previous analysis, thus the rezoning in step 2 above would be necessary when creating the mesh for the new model.

Number of Repetitions

This is the number of elements through thickness of the sweep that were created when the axisymmetric or plain strain elements were swept to make the 3D model. This is required and must be entered before the job is submitted. It is entered in the 3rd field of the 2nd data block of the AXITO3D or PRE STATE option. Not used when analysis is 2D to 2D or 3D to 3D.

306 Marc Preference Guide Load Step Creation

Parameter

Description

Last Increment Increment Time

This is actually a switch. If Last Increment is ON (default), a -1 is written to the 4th field of the 2nd data block of the AXITO3D or PRE STATE option. If Increment is ON, then the databox is enabled and the actual increment number is input. This number is written to the 4th field if this is ON. If Time is ON, the data box to the right is enabled to allow the time to be specified to read from the POST file and a -2 is written to the 4th field. The actual time is written to the 1st field of the 3rd data block if Time is turned ON. If no time is specified, then zero is written.

Select Contact Bodies

For Marc 2005 or greater, you can select the contact body names from the previous model for data transfer to the new model. Note that for this to work, the model from the previous analysis must exist in the Patran database. Generally to have both the previous model and the new, current model in the same database, each needs to be placed in separate Patran groups and submitted for analysis using the Current Group object in the Analysis application. Thisis a feature of PRE STATE only and comprises the 5th datablock.

Select File

The t16 or t19 file is selected from this browser. Field 6 of the 2nd data block is set to zero (0) for binary (t16) or one (1) for ASCII (t19).

Note:

Marc will map the results from the previous analysis to the new analysis model automatically. Note that to do this effectively in Patran with both models in the same database, you will have to put each model in a separate Patran group. When each model is submitted for analysis, the Current Group object should be used in the Analysis application. Make sure the group you wish to submit for analysis is set to the Current Group.

Caution: The previous analysis (axisymmetric/plane strain/etc.) node and element numbering must be consecutive beginining with ID 1 or the PRE STATE mapping will not work and Marc will exit with an error.

Main Index

Chapter 3: Running an Analysis 307 Load Step Creation

Structural Zooming (Global to Local Analysis)

To perform structural zooming, also known as global to local analysis: 1. Run global (course mesh) analysis and save the resulting POST (results) file. 2. Create the local (fine mesh) analysis model. 3. Apply loads and boundary conditions, assign element and material properties to the new model. 4. Set up and submit the job indicating the results file to use for defining boundary conditions of the previous analysis. The boundaries are defined by specifying connecting nodes from the local to the global model. Marc will map the results as boundary conditions from the previous analysis to the new analysis model automatically. Note that to do this effectively in Patran with both models in the same database, you will have to put each model in a separate Patran group. When each model is submitted for analysis, the Current Group object should be used in the Analysis application. Make sure the group you wish to submit for analysis is set to the Current Group. The widgets on this form comprise the data needed for the GLOBALLOCAL option as explained below. Note that the Marc version must be 2005 or greater even to use this feature. Parameter

Main Index

Description

Node Location Tolerance

Exterior tolerance used to find the associated global elements for a connecting node. Default is 0.05 and is placed in the 3rd field of the 2nd datablock of the GLOBALLOCAL option.

If Local run time exceeds Post File time

If the local run time range exceeds the global POST file time range, then the analysis will either Stop, or continue using the End Values for all remaining increments or will Extrapolate depending on this setting. This flag is placed in the 4th field of the 2nd datablock of the GLOBALLOCAL option.

Global-Local Connecting Nodes

Specify the local connecting nodes from which the global boundary conditions will be mapped. Nodes may be graphically selected or geometric entities from which the nodes will be extracted. These nodes are placed in the 4th data block of the GLOBALLOCAL option.

Select File

The t16 or t19 file is selected from this browser. Field 2 of the 2nd data block is set to zero (0) for binary (t16) or one (1) for ASCII (t19).

308 Marc Preference Guide Load Step Creation

Superplastic Forming Superplastic Forming (SPF) jobs require a special pressure load to be applied (usually across the entire surface area, but not always). This is an element variable pressure of unspecified or arbitrary magnitude. A special flag is written to the DIST LOAD option in the input deck. You must specify that the pressure load under Pressure, 52 is set to Element Variable. The 3rd data block has magnitude zero for the pressure value regardless of the magnitude specified in Patran and the 1st field uses a “4” to specify element variable to be determined by MSC.Marc itself (this number varies based on the table below). Thus the appropriate amount of pressure is applied to each element until a certain percentage of the nodes come in contact. This is determined automatically by MSC.Marc. The 4th data block specifies the list of elements to which this pressure load applies. Elem Type

Elements

Load Types

Shell Quad

22, 72, 75, 139, 140

4

Membrane

18, 30

4

Shell Tri

49, 138

4

2D-Solids

OI=PI=SI=NMI=NNI=NVI=OMI=UMI=UNI=UOI=UPI= VRI=NNQI=NNRI=NNSI=NNUI=NNVI=NROI=155, 156

3, 7, 9, 11

26, 27, 28, 29, 32, 33, 34, 53, 54, 55, 56, 58, 59, 60, 62, 63, 66, 67, 73, 74, 91, 92, 93, 94, 96, 153, 154

1, 9, 11, 13

124, 125, 126, 128, 129

1, 5, 9

Hex

7, 21, 35, 57, 61, 84, 107, 108, 117, 120, 149, 150

1, 5, 7, 9, 11, 13

Tet

127,130,134,157

1,3,5,7

Note:

Fields and time dependent loading are not applicable to this application. See MSC.Marc Vol B, Element Library for an explanation of these load types. This type of loading can be used in non SPF analyses.

Aside from element variable pressures, a SPF problem is flagged by the SPFLOW parameter and a SUPERPLASTIC option is placed in the History section for the corresponding Load Step. An SPF analysis is turned ON from the Static Solution Parameters form as shown below if Large Displacements / Large Strains and Loads Follow Deformations are turned ON. Otherwise or selected for the Super Plastic Forming button to be selectable. The button is available under the Solution Parameters form for Static (NonLinear) solution procedure.:

Main Index

Chapter 3: Running an Analysis 309 Load Step Creation

The Superplastic Forming... form appears as follows:

Main Index

310 Marc Preference Guide Load Step Creation

This form allows for the SUPERPLASTIC option parameters to be specified as follows. Part of the SUPERPLASTIC datablocks come from this from while the other part comes from the DIST LOAD options.

Main Index

Chapter 3: Running an Analysis 311 Load Step Creation

Parameter

Description

Superplastic Forming

This is either ON or OFF. It is OFF by default. If it is OFF, no other widget on this form are selectable. This places an SPFLOW parameter in the input deck to flag an SPF analysis. If OFF, no other SPFLOW parameter is written and no SPF analysis is performed.

Minimum Pressure

Specifies the minimum and maximum pressures for this Load Step. These are 3rd and 4th fields of 3rd datablock of SUPERPLASTIC option.

Maximum Pressure Target Strain Rate

Specifies the target strain rate. This is the 1st field of the 3rd datablock of SUPERPLASTIC option.

Strain Rate Sampling

This is the method of strain rate sampling, which can be set to Target or Maximum Strain Rate. For Target, the sampling is done over elements with strain rate > cut-off factor* target strain rate. For Maximum, averaging is done over elements with strain rate > cut-off factor * maximum strain rate. This is the 5th field of the 3rd datablock of SUPERPLASTIC option.

Strain Sampling Cutoff

Specifies the strain rate sampling cutoff for ignoring any values above this number for calculating the average strain rate. This helps in ruling out numerical aberrations. Default is 100 for Target or 0.8 for Maximum sampling rate methods set in the above pulldown menu. For Maximum the value can only vary between zero and one. This is the 2nd fields of the 3rd datablock of SUPERPLASTIC option.

Membrane Pre-Stress

This is applicable to membrane elements only. This is for applying a constant application of prestress for a given number of increments, or to ramp the prestress down to zero linearly over the given number of increments from the prescribed value. This pulldown menu can be set to Off, Constant, or Ramped which supplies a 0, 1, or 2 to the 1st field of the 2nd datablock of SUPERPLASTIC option. If OFF is selected, the Pre-Stress and Number of Increments are disabled.

Pre-Stress

These are 2nd and 3rd fields of 2nd datablock of SUPERPLASTIC option as described in the previous entry.

Number of Increments Finish Criterion

This is either ON of OFF. ON is the default. If OFF, then the Fraction of Nodes in Contact is disabled.

Fraction of Nodes in Contact

This is the 7th datablock of the SUPERPLASTIC option.

Aside for the parameters in the form, the SUPERPLASTIC option also needs datablocks 4, 5, and 6

Main Index

312 Marc Preference Guide Load Step Creation

filled out according to the element variable pressure loads defined. • Datablock 4 - defines the number of sets to define pressure orientation, usually 1. • Datablock 5 - Pressure orientation. This is the sign of the magnitude of the pressure when

defined under the LBCs application as an element variable pressure. Only the sign matters as being positive or negative. This is either -1 or 1 depending on whether the load is negative or positive. • Datablock 6 - This is a list of load indices, usually the same as 1st field of 3rd datablock of DIST

LOADS option. Note:

Marc Vol C, SPFLOW parameter documentation states that SPF problems must use ISOTROPIC option with POWER LAW or RATE POWER LAW options.

Select Load Case This form appears when the Select Load Case button is selected on the Load Step Creation form

A load case must be associated with a Load Step. The load cases contain a collection of loads (forces, pressures, etc.), boundary conditions, and contact definitions. A load case is simply a subset of the Load

Main Index

Chapter 3: Running an Analysis 313 Load Step Creation

Step, which contains more information such as solution type, output requests, and other solution parameters. Note:

Only time dependent load cases should be selected for dynamic analysis. Transient load cases may be selected for static jobs to simulate pseudo-static analysis but make sure that a time dependent field has been associated to the loads.

In the case where Use Tables is set ON, a list of LBCs is given. Only LBCs that do not have fields (time variations) associated with them are listed. You have the option of setting the load application to: • Ramp Up (default)

Ramps the load up gradually over the Load Step. This is normal behavior when not using TABLES.

• Immediate

Applies the load instantaneously in the first increment (not generally recommended).

• Ramp Down

Gradually removes the load over the Load Step. This requires that the LBC be present in the previous Load Step or this option does not make sense. In the case of temperature, returns temperature to initial temperature.

• Remove

Instantaneously removes the load at the begining of the first increment. LBC should be present in previous Load Step for this option to make sense. In the case of temperature, returns temperature to initial temperature.

• Ramp Up/Down

Ramps the load up gradually over the Load Step. If not present in a subsequent Load Step, gradually removes load over the subsequent Load Step. In the case of temperature, returns temperature to initial temperature.

• Ramp Up/Remove

Ramps the load up gradually over the Load Step. If not present in a subsequent Load Step, gradually removes load over the subsequent Load Step but instantly revomes kinematic constraints. In the case of temperature, returns temperature to initial temperature.

• Ramp Down/Remove

Gradually removes the load over the Load Step but instantly removes kinematic constraints. This requires that the LBC be present in the previous Load Step or this option does not make sense. In the case of temperature, returns temperature to initial temperature.

Option writes LOADCASE option with flags 1, 0, -2, -4, 2, 3, -3, respectively.

Output Requests The Output Requests form is used to request results from the Marc analysis for use in postprocessing (POST file) and verification (output file). After the desired results have been requested, the settings can be accepted by selecting the OK button at the bottom of the form. If the Cancel button is selected instead,

Main Index

314 Marc Preference Guide Load Step Creation

the form will be closed without any changes being accepted. Selecting the Defaults button resets the form to the initial default settings. The content of this form is sometimes dependent on the selected solution type. The results types brought into Patran (or MSC.AFEA), due to any of these requests, is documented in Results Created in Patran, 353. Tables are presented there which associate the Marc results postcodes to

the Patran primary and secondary results labels.

Although the output requests can be different from Load Step to Load Step, there are certain aspects of these requests that can only be written once. This is a function of both an Marc limitation and an implementation design decision. For those aspects of output requests that must remain constant regardless of the Load Step, that information is extracted from each Load Step in the Load Step Selection form and the information placed in the Model Definition section of the input file. That which can vary from Load Step to Load Step is placed in the History section. This form remains the same for all Solution Types. Some minor exceptions are noted below.

Main Index

Chapter 3: Running an Analysis 315 Load Step Creation

Output Request

Main Index

Description

Increments between Writing Results (.out file)

Defines the number of increments between writing results to the Marc output file after the first increment of the analysis. This is entered in the second data field on the second card of the PRINT NODE and/or PRINT ELEMENT options.

Select Print Results

This brings up a subordinate form for selecting results to be placed on the output file. See Print Output Requests, 316 for a description of this subordinate form.

Increments between Writing Results (POST)

Defines the number of increments between writing results to the Marc results file after the first increment of the analysis. This is entered as the ninth data field on the second data block of the POST option, for the first Load Step. For subsequent Load Steps, this defines the POST INCREMENT option in the History section and places the integer value in the 1st field of the 2nd data block. If zero (0) or a negative number is given to suppress output, this places a minus one (-1) in this field. The default is one (1) for every increment.

Write Energy Data

By default for Marc Version 2001 or greater, calculated energies are written to both the POST and output files. If this toggle is OFF, then a parameter POST,,n is placed in the input file where n>0 which turns OFF the writing of energy data. Results are treated as global variables on results import. Although this is a Load Step parameter it cannot vary from step to step. So if it is ON in any step, it is ON for all steps.

Select Nodal Results

This brings up a subordinate form for selecting nodal results to be placed on the POST file. This is only visible when the Marc Version on the Translation Parameters form is 2000 or greater. For K7, all nodal results are written by default. See Nodal Output Requests, 319 for list of selectable nodal results.

Select Element Results

This brings up a subordinate form for selecting elemental results to be placed on the POST file. See Element Output Requests, 322 for list of selectable nodal results.

Eigenvalue Output Requests

These parameters can be set for a Normal Modes or Buckling solution.

Normalization Node ID

Defines the node ID used to normalize the mode shapes. This is entered in the 4th data field on the 2nd data block of the RECOVER option. If left blank, it should leave the field blank which will default to zero (0).

Normalization Component

Indicates the degree-of-freedom used to normalize the mode shapes. This is entered in the 5th data field on the 2nd data block of the RECOVER option. The default is zero (0).

316 Marc Preference Guide Load Step Creation

Output Request Reference Amplitude

Description Defines the reference amplitude used to normalize the mode shapes. This is entered in the 6th data field on the 2nd card of the RECOVER option. If left blank, it defaults to zero (0).

Write Results from/thru Mode Defines the starting and ending mode numbers in a range of modes Number to write to the Marc results file. These are the 1st and 2nd data fields on the 2nd data block of the RECOVER option. The default is one (1) for the starting mode and the ending mode can be left blank which defaults to the modes specified on the DYNAMIC or BUCKLE parameters and the field should be left blank. OK

After the desired results have been requested, the settings are accepted by selecting the OK button at the bottom of the form.

Defaults

Selecting the Defaults button resets the form to the initial default settings.

Cancel

If the Cancel button is selected instead, the form will be closed without any changes being accepted.

Note:

The POST option can only be specified globally and cannot change from Load Step to Load Step, however the selected nodal or elemental output can be specified. Output requests are placed on the POST option from all selected Load Steps.

Note:

For the RECOVER option, the 3rd field of the 2nd data block is set to two (2) if the Lanczos method has been selected (field 4 on the DYNAMIC parameter, and field 7 on the BUCKLE parameter), otherwise set it to one (1).

Print Output Requests This button, Select Print Results..., brings up a subordinate form shown below. The information in this form is used to set the PRINT ELEMENT and PRINT NODE options for the first Load Step. For subsequent Load Steps, this varies the print information using PRINT ELEM and PRINT NODE in the History section for each step. The default is for nothing to be printed. The table below explains the widgets in the form below:

Main Index

Chapter 3: Running an Analysis 317 Load Step Creation

Main Index

318 Marc Preference Guide Load Step Creation

Output Requests

Main Index

Description

Nodal Results

This is set to None by default or All or Select. If None is selected, then the PRINT NODE option is not written or a blank line is used for the node list if it is written. If All is selected, the word ALL is placed in the 3rd data block. If Select is selected, the Select Nodal Results list box is activated (otherwise it is disabled).

Select Nodal Results

If this is enabled and one or more items are selected, then the appropriate keywords are placed in the 3rd data block according to PRINT NODE option.

List of Nodes

If a list is placed in the 4th data block if All or Select is selected. If All or Select is used by no list is given, then all nodes are assumed.

Element Results

Works just like Nodal Results above except for PRINT ELEMENT.

Select Element Results

Works just like Select Nodal Results except for PRINT ELEMENT.

List of Elements

Works just like List of Nodes except for elements and PRINT ELEMENT.

Summary

If this is ON, then a SUMMARY option is placed in the Model Definition for the first Load Step or in the History section for subsequent Load Steps. OFF by default.

Echo Input File

No echo of the input data will be written with this OFF. If this is OFF, a $NO LIST is placed in the Parameter section otherwise it is not placed in the input deck. Default is OFF.

Echo Connectivity

No echo of the connectivity data will be written with this OFF. If ON, a 1 is placed in the 3rd field of the 2nd datablock of the CONNECTIVITY option. OFF by default which places a zero there.

Echo Coordinates

No echo of the coordinate data will be written with this OFF. If ON, a 1 is placed in the 4th field of the 2nd datablock of the COORDINATES option. OFF by default which places a zero there.

Print Convergence Ratios

This places a 0 or 1 in the 9th field of the CONTROL option. This is mainly used for monitoring jobs where the convergence ratio is displayed. If this is OFF, the words kçí=^î~áä~ÄäÉ are displayed when monitoring a job.

Error Estimates

This is None (by default) or Stress Discontinuity or Geometric Distortion, or Both. This writes an ERROR ESTIMATE option to the Model Definition section.

Chapter 3: Running an Analysis 319 Load Step Creation

Note:

If neither nodal or elemental output requests are requested, then a NO PRINT option is written.

Nodal Output Requests This subordinate form appears when Select Nodal Results button is selected on the Output Request form. This option is only available for Marc 2000 or higher.

The following post codes are written to the POST option in the 2nd field of the 3rd data block which is repeated for each post code selected. The 1st field requires the word “NODAL”. The nodal results listed are dependent on the Analysis Type as shown in the table.

Main Index

320 Marc Preference Guide Load Step Creation

Nodal Result

Main Index

Postcode

Analysis Type

Default(?)

DISPLACEMENT

1

Structural, Coupled

YES

ROTATION

2

Structural, Coupled

no

EXTERNAL FORCE

3

Structural, Coupled

no

EXTERNAL MOMENT

4

Structural, Coupled

no

REACTION FORCE

5

Structural, Coupled

YES

REACTION MOMENT

6

Structural, Coupled

no

FLUID VELOCITY

7

Coupled

Not yet supported.

FLUID PRESSURE

8

Coupled

Not yet supported.

EXTERNAL FLUID FORCE

9

Coupled

Not yet supported.

REACTION FLUID FORCE

10

Coupled

Not yet supported.

SOUND PRESSURE

11

Coupled

Not yet supported.

EXTERNAL SOUND SOURCE

12

Coupled

Not yet supported.

REACTION SOUND SOURCE

13

Coupled

Not yet supported.

TEMPERATURE

14

Thermal, Coupled

YES

EXTERNAL HEAT FLUX

15

Thermal, Coupled

no

REACTION HEAT FLUX

16

Thermal, Coupled

no

ELECTRIC POTENTIAL

17

Coupled

Not yet supported.

EXTERNAL ELECTRIC CHARGE

18

Coupled

Not yet supported.

REACTION ELECTRIC CHARGE

19

Coupled

Not yet supported.

MAGNETIC POTENTIAL

20

Coupled

Not yet supported.

EXTERNAL ELECTRIC CURRENT

21

Coupled

Not yet supported.

REACTION ELECTRIC CURRENT

22

Coupled

Not yet supported.

PORE PRESSURE

23

Coupled

Not yet supported.

EXTERNAL MASS FLUX

24

Coupled

Not yet supported.

REACTION MASS FLUX

25

Coupled

Not yet supported.

BEARING PRESSURE

26

Coupled

Not yet supported.

BEARING FORCE

27

Coupled

Not yet supported.

VELOCITY

28

Structural, Coupled

no

ROTATIONAL VELOCITY

29

Structural, Coupled

no

Chapter 3: Running an Analysis 321 Load Step Creation

Nodal Result

Main Index

Postcode

Analysis Type

Default(?)

ACCELERATION

30

Structural, Coupled

no

ROTATIONAL ACCELERATION

31

Structural, Coupled

no

MODAL MASS

32

Structural

no

ROTATION MODAL MASS

33

Structural

no

CONTACT NORMAL STRESS

34

Structural, Coupled

no

CONTACT NORMAL FORCE

35

Structural, Coupled

no

FRICTION STRESS

36

Structural, Coupled

no

FRICTION FORCE

37

Structural, Coupled

no

CONTACT STATUS

38

Structural, Coupled

no

CONTACT TOUCHED BODY 39

Structural, Coupled

no

HERRMANN VARIABLE

40

Structural, Coupled

no

PYROLYZED MASS DENSITY

41

Coupled

Not yet supported.

MASS RATE OF GAS

42

Coupled

Not yet supported.

SOLID DENSITY RATE

43

Coupled

Not yet supported.

LIQUID DENSITY RATE

44

Coupled

Not yet supported.

COKE DENSITY RATE

45

Structural, Coupled

no

TYING FORCE

46

Structural, Coupled

no

COULOMB FORCE

47

Structural, Coupled

no

TYING MOMENT

48

Structural, Coupled

no

POST CODE, No. -1 (Scalar)

-1

All

no

POST CODE, No. -2 (Vector)

-2

All

no

Note:

The POST CODE (<0) are for user-defined quantities via user subroutine UPSTNO or other subroutines. POST CODE -1 is recognized as a scalar, -2 as a vector, and any others as scalar values.

Note:

If you do not select any POST codes at all (Nodal or Elemental), no POST option will be written. If you select the Use Nodal POST Code Defaults, then no nodal POST codes will be written, which will flag Marc to use the default nodal POST codes when creating results in the POST file

322 Marc Preference Guide Load Step Creation

Element Output Requests This subordinate form appears when Element Output Requests button is selected on any of the Output Request forms.

Note:

There cannot be more requested integrationpoints placed on the POST file than the number of integration points defined thru the section! Otherwise postprocessing errors can occur.

This form remains the same for all Solution Types. Some minor exceptions are noted below.

Main Index

Chapter 3: Running an Analysis 323 Load Step Creation

Output Requests

Description

Number of Integration Points thru Section

Defines the number of layer points to use through the cross section of homogeneous shells, plates and beams. This number must be odd if not a composite. It is entered in the 2nd field of the SHELL SECT parameter. Default is 5 for top, middle, bottom (and some inbetween).

Write Results for Integration Points (list)

Requests results at locations in the element cross section as a list of integration points. This is entered as the second data field on the third card of the POST option. By default this is a list such as 1 2 3 4 5 or 1:5 for top, middle and bottom (and some inbetween).

Application Region, Bodies, Layers...

For Marc results file format 2007 or higher (POST code revision 13) , you may specify the elements, the contact bodies, and/or specific layers for which to recover result. For previous version, all elements are recovered.

Defaults

Reverts the form back to its defaults.

OK

Closes the form and saves the selections

Cancel

Closes the form and does not save the changes made since the form was opened.

Note:

If no elemental results are selected, and the Marc Version is K7, no POST option is written. If the Marc Version is 2000 or higher, and no nodal or elemental results are selected, no POST option is written.

The following POST codes are written to the POST option in the 1st field of the 3rd data block which is repeated for each post code selected. The elemental results listed are dependent on the Analysis Type as shown in the table.

Main Index

324 Marc Preference Guide Load Step Creation

Elemental Result

Main Index

Postcode

Analysis Type

Solutions

Default(?)

STRAIN, TOTAL COMPONENTS

301

Structural, Coupled

nonlinear only YES

STRAIN, ELASTIC COMPONENTS (defined system)

461

Structural, Coupled

nonlinear only no

STRAIN, ELASTIC COMPONENTS

401

Structural, Coupled

any

no

STRAIN, ELASTIC COMPONENTS (global system)

421

Structural, Coupled

any

no

STRAIN, ELASTIC EQUIVALENT

127

Structural, Coupled

any

no

STRAIN, PLASTIC COMPONENTS

321

Structural, Coupled

nonlinear only no

STRAIN, PLASTIC COMPONENTS (global system)

431

Structural, Coupled

nonlinear only no

STRAIN, PLASTIC EQUIVALENT

27

Structural, Coupled

nonlinear only no

STRAIN, PLASTIC EQUIVALENT (from rate)

7

Structural, Coupled

nonlinear only no

STRAIN, MAJOR ENGINEERING

128

Structural, Coupled

any

no

STRAIN, MINOR ENGINEERING

129

Structural, Coupled

any

no

STRAIN, CRACKING COMPONENTS

381

Structural, Coupled

nonlinear only no

STRAIN, CREEP COMPONENTS

331

Structural, Coupled

creep only

no

STRAIN, CREEP COMPONENTS (global system)

441

Structural, Coupled

creep only

YES

STRAIN, CREEP EQUIVALENT

37

Structural, Coupled

creep only

no

STRAIN, CREEP EQUIVALENT (from rate)

8

Structural, Coupled

creep only

no

STRAIN, THERMAL

371

Structural, Coupled

any

no

Chapter 3: Running an Analysis 325 Load Step Creation

Elemental Result

Main Index

Postcode

Analysis Type

Solutions

Default(?)

STRAIN, THICKNESS

49

Structural, Coupled

any

no

STRAIN, VELOCITY

451

Structural, Coupled

nonlinear only no

STRAIN, TOTAL SWELLING

38

Structural, Coupled

requires User Sub

no

STRESS, COMPONENTS

311

Structural, Coupled

any

no

STRESS, COMPONENTS (defined system)

391

Structural, Coupled

an

no

STRESS, COMPONENTS (global system)

411

Structural, Coupled

any

YES

STRESS, EQUIVALENT 59 YIELD

Structural, Coupled

nonlinear only no

STRESS, EQUIVALENT 60 YIELD (cur. temp.)

Coupled

nonlinear only no

STRESS, EQUIVALENT 17 MISES

Structural, Coupled

any

no

STRESS, MEAN NORMAL

18

Structural, Coupled

any

no

STRESS, INTERLAMINAR SHEAR No. 1

108

Structural, Coupled

any

no

STRESS, INTERLAMINAR SHEAR No. 2

109

Structural, Coupled

any

no

STRESS, INTERLAMINAR COMPONENTS

501,511 251, 254

Structural, Coupled

any

no

STRESS, CAUCHY COMPONENTS

341

Structural, Coupled

nonlinear only no

STRESS, CAUCHY EQUIVALENT

47

Structural, Coupled

nonlinear only no

STRESS, HARMONIC COMPONENTS

351 (real) 361(imag)

Structural

harmonic only no

STRESS, HARMONIC EQUIVALENT

57 (real) 67 (imag)

Structural

harmonic only no

326 Marc Preference Guide Load Step Creation

Elemental Result

Main Index

Postcode

Analysis Type

Solutions

Default(?)

STRESS, REBAR UNDEFORMED

471

Structural

any

no

STRESS, REBAR DEFORMED

481

Structural

any

no

REBAR ANGLE

487

Structural

any

no

FORCES, ELEMENT

264-269

Structural, Coupled

any

no

BEAM, BIMOMENT

270

Structural, Coupled

any

no

BEAM, AXIS

261

Structural, Coupled

any

no

STRAIN RATE, PLASTIC

28

Structural, Coupled

nonlinear only no

STRAIN RATE, EQUIVALENT VISCOPLASTIC

175

Structural, Coupled

any

no

STATE VARIABLE, SECOND

29

All

any

no

STATE VARIABLE, THIRD

39

All

any

no

TEMPERATURE, ELEMENT TOTAL

9

All

any

no

TEMPERATURE, ELEMENT INCREMENTAL

10

Structural, Coupled

any

no

TEMPERATURE, GRADIENT COMPONENTS

181-183

Thermal, Coupled

any

no

FLUX, COMPONENTS

184-186

Thermal, Coupled

any

no

STRAIN ENERGY DENSITY, TOTAL

48

Structural, Coupled

nonlinear only no

FLUX, MASS (components)

194-196

Coupled

any

Not yet supported

FLUX, MASS

279

Coupled

any

Not yet supported

STRAIN ENERGY DENSITY, TOTAL

48

Structural, Coupled

nonlinear only no

STRAIN ENERGY DENSITY, ELASTIC

58

Structural, Coupled

any

no

Chapter 3: Running an Analysis 327 Load Step Creation

Elemental Result

Postcode

Solutions

Default(?)

STRAIN ENERGY DENSITY, PLASTIC

68

Structural, Coupled

nonlinear only no

THICKNESS, ELEMENT

20

All

any

no

VOLUME, ELEMENT (original)

78

All

any

no

VOLUME, CURRENT

69

All

any

no

VOLUME, VOID FRACTION

177

All

any

no

GRAIN SIZE, (79)

79

All

any

no

Structural, Coupled

any

no

FAILURE, INDEX No. 1- 91-103 7 DENSITY, RELATIVE

179

All

any

no

GASKET, PRESSURE

241

Structural, Coupled

any

no

GASKET, CLOSURE

242

Structural, Coupled

any

no

GASKET, PLASTIC CLOSURE

243

Structural, Coupled

any

no

VOLUME, FRACTION OF MARTENSITE

531

Structural, Coupled

any

no

STRAIN, PHASE TRANSFORMATION TENSOR

541

Structural, Coupled

any

no

STRAIN, EQUIVALENT 547 PHASE TRANSFORMATION

Structural, Coupled

any

no

STRAIN, EQUIVALENT 548 TWIN

Structural, Coupled

any

no

STRAIN, EQUIVALENT 549 TRIP

Structural, Coupled

any

no

557

Structural, Coupled

any

no

STRAIN, EQUIVALENT 651 PLASTIC MULTIPHASE AGGREGATE

Structural, Coupled

any

no

STRAIN, EQUIVALENT 652 PLASTIC AUSTENITE

Structural, Coupled

any

no

STRESS, YIELD MULTIPHASE AGGREGATE

Main Index

Analysis Type

328 Marc Preference Guide Load Step Creation

Elemental Result

Main Index

Postcode

Analysis Type

Solutions

Default(?)

STRAIN, EQUIVALENT 653 MARTENSITE

Structural, Coupled

any

no

STRESS, YIELD MULTIPHASE AGGREGATE

657

Structural, Coupled

any

no

PARAMETER, FORMING LIMIT

30

Structural, Coupled

any

no

CONTRIBUTION, HIGHER ORDER

40

Structural, Coupled

any

no

DAMAGE

80

Structural, Coupled

any

no

HARDNESS

90

Structural, Coupled

any

no

VOLTAGE

98

Coupled

any

Not yet supported.

CURRENT

88

Coupled

any

Not yet supported.

HEAT, Generated

89

Coupled

any

Not yet supported.

POTENTIAL, ELECTRIC

130

Coupled

any

Not yet supported.

INTENSITY, ELECTRIC FIELD

561-563 131-133(real) 151-153 (imag)

Coupled

any

Not yet supported.

DISPLACEMENT, ELECTRIC

564-566 134-136 (real) 154-156 (imag)

Coupled

any

Not yet supported.

FORCE, LORENTZ

567-569 137-139 (real) 157-159 (imag)

Coupled

any

Not yet supported.

INTENSITY, MAGNETIC FIELD

574-576 144-146 (real) 164-166 (imag)

Coupled

any

Not yet supported.

POTENTIAL, MAGNETIC

140

Coupled

any

Not yet supported.

Chapter 3: Running an Analysis 329 Load Step Creation

Elemental Result

Main Index

Postcode

Analysis Type

Solutions

Default(?)

INDUCTION, MAGNETIC

571-573 141-143 (real) 161-163 (imag)

Coupled

any

Not yet supported.

DENSITY, CURRENT

577-579 147-149 (real) 167-169 (imag)

Coupled

any

Not yet supported.

POROSITY

171

Coupled

any

Not yet supported.

RATIO, VOID

172

Coupled

any

Not yet supported.

PRESSURE, PORE

173

Coupled

any

Not yet supported.

PRESSURE, PRECONSOLIDAITIO N

174

Coupled

any

Not yet supprted.

PRESSURE

190

Coupled

any

Not yet supported.

PRESSURE, GRADIENT COMPONENTS

191-193

Coupled

any

Not yet supported.

FRACTION, 274 PYROLYSIS CHARRED

Coupled

any

Not yet supported.

FRACTION, PYROLYSIS VAPOR

275

Coupled

any

Not yet supported.

FRACTION, PYROLYSIS COKED

276

Coupled

any

Not yet supported.

EFFECTIVE, RHO C

277

Coupled

any

Not yet supported.

EFECTIVE, K

278

Coupled

any

Not yet supported.

POST CODE, No. 19

19

All

any

no

POST CODE, No. -11

-11

All

any

no

POST CODE, No. -21

-21

All

any

no

POST CODE, No. -31

-31

All

any

no

330 Marc Preference Guide Load Step Creation

Note:

The POST CODE (<0) are for user-defined quantities via user subroutine UPSTNO or other subroutines. POST CODE -11, -21, -31 are recognized as scalar values.

Note:

If you do not select any POST codes at all (Nodal or Elemental), no POST option will be written. If you select the Use Elemental POST Code, Defaults, then no element POST codes will be written, which will flag Marc to use the default elemental POST codes when creating results in the POST file

Direct Text Input This subordinate form appears whenever the Direct Text Input (DTI) button is selected on the Load Step Creation formK=This is different from the DTI form on the Job Parameters, 184 form. This widget is to facilitate the input of the Marc input data that cannot be created using the functionality available in the Preference. All data input here will be placed in the History section of the Marc input file just before the CONTINUE option for the particular Load Set being created. Note:

Main Index

There is no checking for invalid data.

Chapter 3: Running an Analysis 331 Load Step Creation

DTI Parameter

Main Index

Description

Additional History Section Definition

Text in this area will be placed in the History section of the input file just before the CONTINUE keyword for the particular Load Set being created.

Write at Beginning/End

This toggle specifies whether the text is written at the beginning of the Load Step (before anything for this particular step) or at the end (before the last CONTINUE option). End is default.

Clear

This clears the text in the text data box for the section that is selected.

Cancel

This closes the form without any changes saved.

Apply

This closes the form and saves the changes made for this Load Set.

Read From File

Will populate the text data box with text from the indicated file. This brings up a typical file browser to select the file.

332 Marc Preference Guide Load Step Selection

Load Step Selection This subordinate form appears whenever the Load Step Selection button is selected on the main Analysis form. This form is used to select and order the Load Steps that will be analyzed for the Marc job. At least one Load Step must be selected and appear in the Selected Load Steps list box. Once a load step or load steps have been selected, you may submit the job by pressing the Apply button on the main Analysis application form.

Note:

Main Index

A Default Static Step is always available for linear or nonlinear static analysis. It is also automatically selected for you by default. It is therefore unnecessary to select a Load Step if the default is adequate. Other solution types or multiple step analysis requires that you create additional Load Steps. See Load Step Creation, 231 for information on how to create Load Steps. An error will be issues if you select Load Steps that are not valid for the set analysis type: Structural, Thermal, or Coupled.

Chapter 3: Running an Analysis 333 Load Step Selection

Multiphysics Selection In th e Coupled analysis type, you can specify coupling between different types of physical phenomenon. The default is thermal-mechanical or structural-thermal coupling, in which case you do not need to open this form at all. If you wish to do purely structural, or purley thermal, or electrostatic or electrodynamicthermal coupling, then you must select the coupled physics types in this form.

Main Index

334 Marc Preference Guide Domain Decomposition

Domain Decomposition

DDM Interface Each widget of this form is discussed in the table below.

Main Index

Chapter 3: Running an Analysis 335 Domain Decomposition

Main Index

336 Marc Preference Guide Domain Decomposition

DDM Parameter

Main Index

Description

Decomposition Method

Set this to Automatic (available only in Marc Version 2005 and higher) if you wish Marc to automatically create the domains during analysis run time. Set to Semi-Automatic if you wish to have Patran automatically break the model into domains which can be visualized before submittal. Set to Manual to have full control over the domains. This requires the creation of the groups before they can be selected here in this form and associated to a domain.

Number of Domains

This determines how many domains are to be created. When you change this number and press the Enter or Return key, the spread sheet updates with this number of rows. The default is 2. This corresponds to the number of CPUs desired to run the job. For the Automatic method, this is the only input that is required and the spreadsheet is not visible.

Metis Method Domain Island Removal Coarse Graph

These are parameters used when the Decomposition Method is set to Automatic. The decomposer uses the Metis algorithm which can be set to Best (default), Node Based or Element Based. Also the two toggles, Domain Island Removal and Coarse Graph can be set ON or OFF, which affect the decomposer. For more detail, see the MSC.Marc documentation. When any settings other than the defaults of these widgets are set, the PROCESSOR parameter is written to the input deck.

Single POST File

In Marc 2005 and beyond, a single input file can be used for Domain Decomposition runs. A single results output (POST - t16/t19) file can also be requested but setting this toggle. This puts a one (1) in the 5th field of the 2nd data block of the POST option.

Create

To create more or less domains, you change the Number of Domains widget accordingly and press this button or the Return or Enter key which updates the Domain Information spread sheet.

Visualize

By pressing this button, all groups currently posted will be unposted. The groups from the selected rows of the spreadsheet will be color coded and posted. The plot will be wireframe. It can be turned into shaded or hidden plot with the standard tools. Only domains from the selected spreadsheet rows will be plotted. If a row is not selected, that domain will not be plotted.

Validate

By pressing this button, all domains will be validated that there are no duplicate or overlapping elements. A message will be placed in the Patran command line window.

Reset Graphics

This will return the graphics screen back to the way it was before you pressed Visualize. If you exit the tool, the graphics will also be reset as if this button were pressed.

Chapter 3: Running an Analysis 337 Domain Decomposition

DDM Parameter

Description

Model / Current Group

This switch is used for Automatic and Semi-Automatic DDM only. For Automatic, either the entire Model or the Current Group is translated into the input deck. For Semi-Automatic, this dictates on what part of the model the decomposition is done (not what is translated to the input deck). This is not applicable for Manual decomposition.

Domain Information

This spreadsheet is created when the Create button is pushed or the Number of Domains is changed. The number of rows is dependent on the Number of Domains specified. Any cell in any row may be selected. Multiple rows may be selected. Although not all cell contents can be changed. This depends on the Decomposition Method setting. For Automatic, this information is not visible.

Domain

This column of the spreadsheet is hard coded and simply says Domain 1, Domain 2, etc. for each domain. It cannot be changed but is selectable.

Group

This column lists the group that makes up the connectivity for the domain. If Decompose Domains By is set to Manual, these cells are initially empty. You must select the cell in which the Select a Group list box becomes visible and you can select the group for that domain.

Select a Group

For Manual decomposition, you must select a group from this listbox when one of the cells is selected in the Domain Information spread sheet. If you do not see the group you desire here, it is likely that it has not been created. Create groups in the Groups | Create pulldown menu from the main Patran menu bar.

Use LSF

If this toggle is ON, then the Host File button is no accessible because the LSF load sharing facility is used to submit the job. The optimum machines are found based on the LSF configuration. See Submittal to LSF Queues, 13 for more detail.

Host File

This brings up a file browser to select the hostfile which contains information about the machines and number of CPUs as well as scratch disk and Marc executable locations. This is required if submitting a parallel job to a cluster of homogeneous machines. This is not required for submitting to a single machine with multiple processors.

Do Not Copy Files Copy Files

When submitting to a cluster of machines, this dictates whether files are copied or not. By default files are not copied, assuming they reside in a shared directory. See DDM Submittal, 338 below.

OK

Closes the form and saves all settings or changes.

Defaults

This will return the form to its factory default settings.

Cancel

Closes the form but does not save any changes you made.

Some notes on the operation of the graphical interface:

Main Index

338 Marc Preference Guide Domain Decomposition

If an Semi-Automatic operation is redone, it resets everything and it overwrites the groups. To delete groups, you must do it through the Group application. So take care, because it is easy to perform the decomposition multiple time. But each time new groups are created and they are not automatically deleted. You can mix and match the different methods of creating domains. For example, you can do this: press the Create button with the Semi-Automatic methods then change the method to the Manual setting and change the group. On the Manual setting you can also change the Number of Domains and have the spreadsheet update without losing any already defined information such as adding more domains. Note:

A key criterion for running a successful DDM job is for you to make certain that the node and element numbering for the entire model is consecutive. For example a model with nodes 1-100 and elements 1-250 will work fine. But a model with nodes 1-50, 52-151 and elements 1-200, 202-251 will not work.

DDM Submittal This section discusses the mechanics of a DDM analysis. In general, by default a DDM job is submitted as follows: • Single Machine: run_marc -j jobname -nproc #

• Network: run_marc -j jobname -nproc # -host hostfile -ci NO -cr NO

Where nproc is the number of processors (#). Only the network submittal needs the hostfile information. For single file DDM submittals (automatice DDM), -nps is used instead of -nproc. In either case, a DDM job may be submitted from the Marc Preference locally or to a remote machine. For remote submittal, the MarcSubmit program copies all necessary files to the machine the job is submitted to and then the Marc DDM job is submitted. After completion, the MarcSubmit program copies all files back to the machine the job was submitted from for use in post-processing. There are four mechanisms for submitting DDM jobs depending on the Marc Version and whether a single machine with multiple processors has been selected, or a cluster of machines. 1. Single Machine - Automatic A single input file is created and submitted to a machine using Marc 2005 (or greater) which automatically performs the decomposition and takes advantage of the multiple processor machine. 2. Single Machine - Manual or Semi-Automatic An input file is created for each domain called #jobname.dat (where the # is the domain number) plus the master input file (jobname.dat) and submitted to a machine using any Marc version. Each #jobname.dat file is submitted to one of the processors of the multiple processor machine. 3. Cluster of Machines - Automatic

Main Index

Chapter 3: Running an Analysis 339 Domain Decomposition

A single input file is created and submitted to a machine using Marc 2005 (or greater) which automatically performs the decomposition and takes advantage of the cluster of machines specified in the hostfile. 4. Cluster of Machines - Manual or Semi-Automatic An input file is created for each domain called #jobname.dat (where the # is the domain number) plus the master input file (jobname.dat) and submitted to a machine using any Marc version. Each #jobname.dat files is submitted to one of the machines in the cluster specified in the hostfile. By default the input files and the output results files are not copied to each machine locally but are assumed to reside in a shared or nsf mounted directory. This is done with the -ci NO and -cr NO options, respectively. If the files are to be copied then these options are not used and this necessitates that scratch directories be specified in the hostfile. The files are then copied to and from these scratch directories on each of the machines in the hostfile. As can be deciphered from the above, in Marc 2005 (or beyond) all you need is a single input file for submitting a DDM analysis job. For previous versions of MSC.Marc, several input files are created for submitting a DDM job. The total number of files created in this case is equal to the number of subdivisions of the model plus one additional file. A baseline file that has no model or history information is created called jobname.dat. The rest of the files created are 1jobname.dat, 2jobname.dat, etc. up to the number of domains created. Each of these files contains coordinate and connectivity data for its domain only. Any options that reference element or node numbers will be contained in that domain exclusively. Besides this the rest of the information contained in the input files are identical. If you are using Marc 2005 (or beyond), submitting an input file for analysis is enhanced and simplified. Only a single file is submitted for DDM in MSC.Marc 2005 and beyond however, the old method can still be used if multiple files are supplied. Note:

There are multiple results (POST) files from a DDM run just as there are input files. There is one for each domain by the same names with the .t16 or .t19 file extension. In order to view these results, it is only necessary to attach to the master jobname.t16/t19 file.

DDM Configuration Below are a few notes for proper configuration of DDM. However, please see the Marc Parallel Version for Windows NT / UNIX Installation and User Notes for proper configuration of Marc DDM. Marc DDM must be configured properly in order for DDM to work properly from Patran. If you have trouble, please check the following: On Windows machines: 1. Make sure PaTENT MPI (Marc 2003 or earlier) or the Cluster Manager service (Marc 2005 and greater) is installed and running as a service. 2. Make sure you have a valid license of PaTENT MPI service if necessary (Marc 2003 or earlier. The license file is generally found under \marc200x \patentmpi\admin\license.dat. Contact MSC if this license has expired.

Main Index

340 Marc Preference Guide Domain Decomposition

3. When using a cluster of Windows machines it is recommended that all input files be in a shared directory when you submit the job (in other words, submit the job from a shared directory that all machines can see). 4. The Marc installation on the master host should be in a shared directory also unless all machines have their own installation of Marc, and then they must be properly referenced in the hostfile. 5. If you are submitting from a Windows machine to a UNIX machine, make sure that you have a valid .rhosts file in your home directory. Place the name of the Windows machine and the remote machine you are submitting to in the .rhosts file. The name must appear exactly as is when you do a top command on the UNIX machine when you have a telnet session open from your Windows machine. 6. If you cannot do an rsh or an rlogin from your Windows machine to the UNIX machine then there is something wrong with your remote access as set up by the .rhosts file. Check with a system administrator. On UNIX: 1. You must be able to rlogin to all referenced machines in the hostfile without supplying a password. If you cannot, check that your .rhosts file has the name of all the machines in it. Check with a system administrator if you need help. 2. Only homogeneous clusters of machines are truly supported. They must all be running the same MPI service or daemons. For example a cluster of 64 bit HP machines must all use the HP MPI; a cluster of 32 bit HP machines can use either HP MPI or MPICH, but not a mixture; heterogeneous clusters should work if they all use MPICH but this is not officially supported; UNIX and Windows clusters are not supported.

Main Index

Chapter 3: Running an Analysis 341 Resolving Convergence Problems

Resolving Convergence Problems For complex models involving multiple forms of nonlinear behavior the tried and true approach (particularly if you are new to this type of problem) is to start with a linear model and add nonlinearities one at a time. Alternatively, remove the nonlinearities one at a time until it runs. This approach helps you determine which type of nonlinearity is causing the convergence problem. If you have contact, remove it and let the bodies pass through one another or replace the contact condition with an equivalent displacement constraint. If you have nonlinear materials replace them with simple elastic ones. Add the nonlinearities back one at a time, making sure the behavior is reasonable and correct. If you run the analysis and it does not run at all, or ends before completing, you will get an error message in the jobname.out or jobname.log file that will give you an indication of what the problem is. Do a text search on the word error in the jobname.out file. The first thing to check is to make sure you were able to get a license to run the job. Licensing problems are one of the most common reasons for a run to fail. If you are sure you have a license and submit the job correctly you should get a jobname.out file that will end with an Marc Exit # preceeded by a description of why the run stopped. Common Exit #'s are: • Exit 3004 - success. The job ran to completion and did everything you asked. • Exit 13 - syntax error in the input file. You should check the input syntax of the line the error

message points to, but it is likely that the actual error was in the input block prior to where the message points. • Exit 2004 - typically means non-convergence due to rigid body motions. See recommendations

for equilibrium below. • Exit 3002 - means the analysis ran into convergence problems part way through and did not

complete. Any Exit Message of 3000 or higher means there are converged increments. Plot the converged increments to see what is going on. See Technical Application Note 4575 or Marc Volume C: Program Input, Appendix A of for a more complete list with suggested fixes. Things to consider if your Marc model does not converge: 1. Equilibrium - Make sure your model has LBCs and contact conditions that will ensure force equilibrium at every increment/iteration and for all rigid-body modes (typically there are 6). When in doubt either: • Eliminate this as the source of nonconvergence by intentionally over constraining the model

(or adding soft springs) and then removing constraints one at a time until you figure out the unconstrained rigid body mode or • Under Analysis | Job Parameters | Solver Options turn Non-Positive Definite ON. This

can also be controlled step to step under Load Step Creation | Solution Parameters | Iteration Parameters. One area that is sometimes overlooked regarding equilibrium is that of the rigid body control. If you do not specify adequate control information (e.g., you forget to add the zero that fixes the rigid body rotation value) you may have convergence problems.

Main Index

342 Marc Preference Guide Resolving Convergence Problems

2. LBCs - When LBCs are removed, the ABAQUS Preference causes the removal of the forces/pressures (and the reaction forces due to displacement constraints) gradually over the subsequent step. The Marc Preference will remove forces and pressures gradually, but the reaction forces of displacement constraints are removed suddenly at the beginning of the subsequent step unless the RELEASE option is used when defining a contact table (under Load Step Creation | Solution Parameters | Contact Table). This sudden change in loading can cause convergence problems. 3. Stability and Collapse - Nonconvergence will occur when a structural instability (i.e., buckling) mode is encountered. Buckling can occur either locally (in highly stressed areas where the stability of individual elements is exceeded - adaptive re-meshing will help this) or globally when the critical buckling load (Pcr) of any part of the model is exceeded. You may want to do a linear buckling analysis to determine the load that would buckle the least stable part of the structure. If you suspect that you are approaching the postbuckled region here are some other things to try: • Try using Marc’s quasi-static inertial damping (turn this on under Analysis | Load Step

Creation | Solution Parameters |) or use one of the Arc-length methods. This will help get through the unstable region if doing a snap-through buckling problem, and may help get you past one or two elements of local buckling, but probably not more than that. • Try a finer mesh (smaller elements have shorter length and so higher Pcr).

4. Materials - Make sure that the material coefficient values are realistic and that the models will support the stresses and loads developed in the model. For example if you hang a 1000 lb. weight from a perfectly plastic wire with a 0.001 in2 cross section and a 20 ksi yield stress, the resulting 100 ksi stress cannot be supported by the (20 ksi yield stress) material and the run will not converge. Comparable behavior in bending is referred to as a plastic hinge. Unit mismatches will often result in this type of problem (note that this only occurs in nonlinear analyses). For example, let us say you are modeling a cantilever beam and using a perfectly plastic material model and a follower force tip load, and you mistakenly add an extra zero to the tip load. A plastic hinge will develop with the beam winding up like a spring and the analysis continuing to run until it runs out of increments (which may take a long time). If you suspect this type of problem, first run the problem with a small fraction of the load to see if it will converge. If you are using an ortho/anisotropic material it is possible to select combinations of material properties that will result in a non-positive definite material coefficient matrix. Normally the analysis code will warn you if you violate this requirement. 5. Contact - If the is a problem with chattering (a condition where a particular node jumps into and out of contact thus preventing the increment from converging), you can go to Job Parameters | Contact Control Parameters | Separation and set the Chattering toggle to Suppress. The parameters which have the biggest effect on contact behavior are Contact Distance Tolerance, D (see Figure B-1), Bias Factor, B (see Figure B-2), and Separation Force. By default Marc uses D = 1/20th of the element edge length. You can find the specific value in the jobname.OUT file and try a larger or smaller value, whichever you feel is most appropriate. Marc’s default on the bias value is 0, if having problems with contact one of the first things to try is to override this value on the Analysis | Job Parameters | Contact Parameters | Contact Detection form with 0.9.

Main Index

Chapter 3: Running an Analysis 343 Resolving Convergence Problems

Another option would be to increase the separation force (which defaults to 0) to prevent chattering. When considering contact problems look for places (such as corners and other discontinuities) where one contact surface may slip off. Marc has a capability to delay slide-off when defining a contact table. Standard steps to resolving convergence problems: If your model does not run, or stops pre-maturely, first read the messages in the jobname.msg, jobname.log, and jobname .out files. The jobname.msg file will tell you if there were any problems translating the model into the Marc input jobname.dat file and the jobname.out file will tell you why the Marc run failed. Common causes of the Marc run to fail include: • un-constrained rigid body modes • 2) you are in the post-buckled region • 3) problems resolving contact • 4) some part of the model/material is over-constrained such that the given displacement solution

does not change when the load is increased (i.e., individual elements are buckling locally), this type of nonunique solution can prevent convergence. See the appropriate section above for possible solutions. After trying the obvious things talk to other experienced users about possible reasons your run is not working. In one case a user was using the standard element formulation with Poisson’s Ratio (ν) = 0.5 and HEX/27 elements and his model would not converge even though there were no obvious problems. For this case using the constant volume formulation should provide a unique solution and allow convergence, unless ν = 0.5 causes numerical problems. In that case you should use the Herrmann elements (which also requires using the constant volume formulation) and which should take care of the numerical problems as well as the nonunique solution problem. If these options do not work you could try using reduced integration, which may solve both problems at once, but may have problems with energy-free or spurious deformation modes (also called hour-glassing), although Marc has built-in hour glass stabilization. Also, try quasi-static inertial damping or an arc-length method. Here are some other things to try: • Try a finer mesh • Modify the material model • if it is simple elastic, perfectly plastic with large plastic strains try using constant volume

Herrmann elements. • if using a hyper-elastic material model try lowering ν from 0.5 to maybe 0.49 or so (or lower

if you have to) • make sure it is based on test data that includes the type of behavior you are trying to model

(i.e. if your test data is from a uniaxial tensile test and you are modeling a pressurized cylinder, which is a biaxial stress state, try analyzing a simple biaxial sheet to see if your hyperelastic material model will successfully handle biaxial stress states. If not you may have to include some bi-axial test data (hyperelastic models based on test data should include at least two deformation modes, although Marc has a new Arruda-Boyce model which is supposed to be accurate with only one mode of experimental data).

Main Index

344 Marc Preference Guide Resolving Convergence Problems

• Simplify - if the model you are running is a 3D cylinder made of solid elements, run a 2D

axisymmetric test case to check out the mesh refinement and material model. If not in the postbuckled region try: 1. Look at deformed shape to see if it looks reasonable (by default in the Marc Preference uses a true scale factor = 1 to show the actual deformation). Remember that static equilibrium must be maintained at every step. 2. Check reaction forces to see if the load path is reasonable. 3. Look for highly distorted elements, both visually and in the jobname.out file. If you find any, you may need to go back and refine your mesh in that area to keep those elements well-behaved, i.e., converging, or use adaptive re-meshing. Although distorted elements will normally just give you bad results but not necessarily prevent convergence. Typically linear elements (i.e., quad/4 instead of quad/8) do better in analyses where severe distortion is expected. 4. If using contact elements you may be able to ease convergence problems by simplifying the contact interaction • Look at the jobname.sts file for the # of increment splits and # of separations to see if

contact is the problem • Set bias to 0.9, increase (or decrease) the contact tolerance distance, suppress chattering • Modify the contact table to eliminate suspected trouble areas (at least as a diagnostic measure) • Look for areas where contact bodies may be sliding off

5. Pay attention to the messages in the jobname.msg and jobname.out files, they may tell you why the model was not translated or convergence was not reached and the analysis terminated. 6. If nonconvergence relates to inelastic behavior of the material, such as in a plasticity analysis, make sure there are no plastic hinges formed, where static equilibrium cannot be achieved because the material is not strong enough, in this case all the iterations go to deforming the body around the plastic region and static equilibrium may never be reached. 7. When doing a hyperelastic material analysis the material model may be unpredicatable since the coefficients are generally quite unintuitive. The run may not converge simply because the material model, while it may look reasonable, may actually be inherently unstable (things like negative energy behavior, etc.). 8. Make sure you are not stuck at a stability bifurcation point, (i.e., at a buckling mode). What may be happening is that there are two valid (postbuckling in this case) equilibrium paths and the code flips back and forth between them preventing convergence. The way to get past this is to make the problem dynamic and use the inertia of the body to select the appropriate equilibrium path. Again, the tried and true method is to start with a linear model and add nonlinearities one at a time, or remove nonlinearities one at a time until the model runs.

Main Index

Chapter 4: Read Results Marc Preference Guide

4

Main Index

Read Results



Read Results Form



Select Results File



Translation Parameters



Results Created in Patran



Direct Results Access

348 349 350

362

353

348 Marc Preference Guide Read Results Form

Read Results Form

The Analysis application, located on the main form, appears when selected. Read Results as the selected Action allows the results data to be read into or attached to the Patran (or MSC.AFEA) database from a text (jobname.t19) or binary (jobname.t16) Marc results file.

This default process of attaching a results file is referred to as Direct Results Access (DRA). Some more details are given in Direct Results Access, 362.

Main Index

Chapter 4: Read Results 349 Select Results File

Select Results File This form appears when the Select Results File button is selected in the Analysis application when Read Results is the selected Action. The form allows a specific file to be read. It is best to select the file before setting any translation parameters as explained in the next section. However it is not actually necessary to select a file at all if the results file name has the same name as the Job Name. It will automatically be assumed if no results file is specifically selected. The jobname.t16 file will be selected first if it exists, then, the jobname.t19 if it exists. If neither exist an error will be issued and you will have to manually select a file from this form.

Main Index

Note:

The default file filters may be changed from *.t16 to *.t19 to display the available text result files or set the filter to *.t1* to see both.

Note:

Once a file has been attached, it can be detached by setting the Action to Delete and the Object to Results Attachment on the Analysis application.

350 Marc Preference Guide Translation Parameters

Translation Parameters A form appears when the Translation Parameters button is selected in the Analysis application when Read Results is the selected Action. Only a portion of this form may appear depending on the selected Object, i.e., Result Entities, Model Data, or Both. There are two Translation Parameters forms. One for result file Attachments and one for result file Import. This depends on the setting of the Method pulldown menu from the main Analysis application form when the Action is set to Read Results.

Result Attachment Translation Parameters For attached results files the following form appears:

Main Index

If this toggle is ON, then all meshes from an adaptive mesh analysis are imported automatically even if the Object is set to Result Entities only. If the original mesh already exists in the database, then all subsequent meshes are imported.

Chapter 4: Read Results 351 Translation Parameters

Result Import Translation Parameters For results import, the following form is available to filter results

Main Index

352 Marc Preference Guide Translation Parameters

Note:

Main Index

Import of adaptive meshing results is not supported. You must use the Attach method.

Chapter 4: Read Results 353 Results Created in Patran

Results Created in Patran The following table indicates all the possible result quantities which can be loaded into the Patran database during results translation from Marc. The Primary and Secondary Labels are items selected from the postprocessing menus. The Type indicates whether the results are Scalar, Vector, or Tensor. These types will determine which postprocessing techniques will be available in order to view the results quantity. Postcodes indicates which Marc element postcodes the data comes from. The Description gives a brief discussion about the results quantity. The Output Requests, 313 forms use the actual primary and secondary labels which will appear in the results. For example, if “Strain, Elastic” is selected on the Element Output Requests form, the “Strain, Elastic” is created for postprocessing. Note:

Main Index

fmport of adaptive meshing results is not supported. You must use the Attach method.

354 Marc Preference Guide Results Created in Patran

Primary Label

Main Index

Secondary Label

Type

Postcodes

Description

Displacement

Translation

Vector

1 (nodal)

Translational displacements at nodes from a structural analysis.

Displacement

Rotation

Vector

2 (nodal)

Rotational displacements at nodes from a structural analysis.

Velocity

Translation

Vector

28 (nodal)

Translational velocities at nodes from a dynamic analysis.

Velocity

Rotation

Vector

29 (nodal)

Rotational velocities at nodes.

Acceleration

Translation

Vector

30 (nodal)

Translational accelerations at nodes from a dynamic analysis.

Acceleration

Rotation

Vector

31 (nodal)

Rotational accelerations at nodes from a dynamic analysis.

Force

Nodal External Applied

Vector

3 (nodal)

Forces applied to the model in a structural analysis.

Force

Nodal Reaction

Vector

5 (nodal)

Reaction forces at boundary conditions from a structural analysis.

Moment

Nodal External Applied

Vector

4 (nodal)

Moments applied to the model in a structural analysis.

Moment

Nodal Reaction

Vector

6 (nodal)

Reaction moments at boundary conditions from a structural analysis.

Modal Mass

Translation

Vector

32 (nodal)

Translational modal masses from modal extractions.

Modal Mass

Rotation

Vector

33 (nodal)

Rotational modal masses from modal extractions.

Temperature

Nodal

Scalar

14 (nodal)

Temperature at nodes from a thermal analysis.

Velocity

Fluid

Vector

7 (nodal)

Fluid Velocity

Chapter 4: Read Results 355 Results Created in Patran

Primary Label

Main Index

Secondary Label

Type

Postcodes

Description

Flux

Nodal

Scalar

15 (nodal)

Heat Flux applied to the model in a thermal analysis.

Pressure

Fluid

Scalar

8 (nodal)

Fluid Pressure

Force

External Fluid

Vector

9 (nodal)

External Fluid Force

Force

Reaction Fluid

Vector

10 (nodal)

Reaction Fluid Force

Pressure

Sound

Scalar

11 (nodal)

Sound Pressure

Source

External Sound

Scalar

12 (nodal)

External Sound Source

Source

Reaction Sound

Scalar

13 (nodal)

Reaction Sound Source

Flux

Nodal Reaction

Scalar

16 (nodal)

Nodal Reaction Flux

Potential

Electric

Scalar

17 (nodal)

Electric Potential

Charge

External Electric

Scalar

18 (nodal)

External Electric Charge

Charge

Reaction Electric

Scalar

19 (nodal)

Reaction Electric Charge

Potential

Magnetic

Scalar

20 (nodal)

Magnetic Potential

Current

External Electric

Scalar

21 (nodal)

External Electric Current

Current

Reaction Electric

Scalar

22 (nodal)

Reaction Electric Current

Pressure

Pore

Scalar

23 (nodal)

Pore Pressure

Flux

External Mass

Scalar

24 (nodal)

External Mass Flux

Flux

Reaction Mass

Scalar

25 (nodal)

Reaction Mass Flux

Pressure

Bearing

Scalar

26 (nodal)

Bearing Pressure

Force

Bearing

Scalar

27 (nodal)

Bearing Force

Stress

Contact Normal

Vector

34 (nodal)

Contact Normal Stress

Force

Contact Normal

Vector

35 (nodal)

Contact Normal Force

Stress

Friction

Vector

36 (nodal)

Friction Stress

356 Marc Preference Guide Results Created in Patran

Primary Label

Main Index

Secondary Label

Type

Postcodes

Description

Force

Friction

Vector

37 (nodal)

Friction Force

Contact

Status

Scalar

38 (nodal)

Contact Status

Contact

Touched Body

Scalar

39 (nodal)

Touched Body Contact

Variable

Herrmann

Scalar

40 (nodal)

Herrmann Variable

Post Code

No. -1

Scalar

-1 (nodal)

User defined nodal quantities via user subroutine.

Post Code

No. -2

Vector

-2 (nodal)

User defined nodal quantities via user subroutine.

Post Code

No. -11, -21, - Scalar 31

-11, -21, -31

User defined elemental quantities via user subroutine.

Post Code

No. 19

Scalar

19

User defined variable via user subroutine PLOTV.

Post Code

No. 38

Vector

38

Total swelling strain from user subroutine VSWELL.

Strain

Cracking

Tensor

81-86 or 381

Cracking strain from a nonlinear structural analysis.

Strain

Creep

Tensor

31-36 or 331

Creep strain from a nonlinear structural analysis.

Strain

Creep Equivalent

Scalar

37

Equivalent creep strain from a nonlinear structural analysis.

Strain

Creep Equivalent (from rate)

Scalar

8

Equivalent creep strain determined from rate from a nonlinear structural analysis.

Strain

Elastic

Tensor

121-126 or 401

Elastic strain from a structural analysis.

Strain

ElasticCompo Tensor nents

421

Elastic strain components from a nonlinear structural analysis in the global coordinate system.

Strain

ElasticCompo Tensor nents

461

Elastic strain components from a nonlinear structural analysis in the preferred coordinate system.

Strain

Plastic Components

Tensor

431

Plastic strain components from a nonlinear structural analysis in the global coordinate system.

Strain

Elastic Equivalent

Scalar

127

Equivalent elastic strain from a structural analysis.

Chapter 4: Read Results 357 Results Created in Patran

Primary Label

Secondary Label

Postcodes

Description

Strain

Plastic

Tensor

21-26 or 321

Plastic strain from a nonlinear structural analysis.

Strain

Plastic Equivalent

Scalar

27

Equivalent plastic strain from a nonlinear structural analysis.

Strain

Plastic Equivalent (from rate)

Scalar

7

Equivalent plastic strain determined from rate from a nonlinear structural analysis.

Strain

Plastic Equivalent Rate

Scalar

28

Equivalent plastic strain rate from a nonlinear structural analysis.

Strain

Thermal

Tensor

71-76 or 371

Thermal strain from a structural analysis.

Strain

Thickness

Scalar

49

Thickness strain from a structural analysis.

Strain

Total

Tensor

1-6 or 301

Total strain from a nonlinear structural analysis.

Temperature

Element

Scalar

9

Element temperature from a thermal or structural analysis.

Temperature

Element Gradient

Vector

181-183

Element temperature gradient from a thermal analysis.

Temperature

Element Incremental

Scalar

10

Incremental element temperature from a thermal or structural analysis.

Tensor

11-16 or 311

Stress from a structural analysis.

Stress

Main Index

Type

Stress

Cauchy

Tensor

41-46 or 341

Cauchy stress from a nonlinear structural analysis.

Stress

Cauchy Equivalent Mises

Scalar

47

Equivalent Cauchy stress from a nonlinear structural analysis.

Stress

Equivalent Mises

Scalar

17

Equivalent (von mises) stress from a structural analysis.

Stress

Hydrostatic

Scalar

18

Hydrostatic stress from a structural analysis.

Stress

Interlaminar Shear No. 1

Scalar

108

Interlaminar shear in one direction from a structural analysis.

Stress

Interlaminar Shear No. 2

Scalar

109

Interlaminar shear in two direction from a structural analysis.

358 Marc Preference Guide Results Created in Patran

Primary Label

Main Index

Secondary Label

Type

Postcodes

Description

Energy Density

Elastic

Scalar

48

Elastic strain energy density from a structural analysis.

Energy Density

Plastic

Scalar

58

Plastic strain energy density from a nonlinear structural analysis.

Energy Density

Total

Scalar

68

Total strain energy density from a structural analysis.

Flux

Element

Vector

184-186

Element heat flux from a thermal analysis.

State Variable

Second

Scalar

29

Second state variable from a nonlinear thermal or structural analysis.

State Variable

Third

Scalar

39

Third state variable from a nonlinear thermal or structural analysis.

Failure

Index No. 1

Scalar

91

Failure index one from a structural analysis.

Failure

Index No. 2

Scalar

92

Failure index two from a structural analysis.

Failure

Index No. 3

Scalar

93

Failure index three from a structural analysis.

Failure

Index No. 4

Scalar

94

Failure index four from a structural analysis.

Failure

Index No. 5

Scalar

95

Failure index five from a structural analysis.

Failure

Index No. 6

Scalar

96

Failure index six from a structural analysis.

Failure

Index No. 7

Scalar

97

Failure index seven from a structural analysis.

Thickness

Scalar

20

Element thickness from a thermal or structural analysis.

Volume

Scalar

78

Element Volume from a thermal or structural analysis.

Beam

Bimoment

Scalar

270

Bimoment.

Grain Size

(79)

Scalar

79

Grain size.

Volume

Fraction of Martensite

Scalar

531

Volume fraction of Marensite.

Strain

Phase transformatio n tensor

Tensor

541

Phase transformation strain tensor.

Chapter 4: Read Results 359 Results Created in Patran

Primary Label

Secondary Label

Type

Postcodes

Description

Strain

Equivalent Phase Transformati on

Scalar

547

Equivalent Phase Transformation strain.

Strain

Equivalent TWIN

Scalar

548

Equivalent TWIN Strain.

Strain

Equivalent TRIP

Scalar

549

Equivalent TRIP Strain in the forward transformation.

Stress

Yield of Mulitphase Aggregate

Scalar

557

Yield Stress of Multiphase Aggregate

Strain

Equivalent Plastic in Multiphase Aggregate

Scalar

651

Equivalent Plastic Strain in the Multiphase Aggregate

Strain

Equivalent Plastic in Austenite

Scalar

652

Equivalent Plastic Strain in the Austenite

Strain

Equivalent Plastic in Martensite

Scalar

653

Equivalent Plastic Strain in the Martensite

Stress

Yield of Multiphase Aggregate

Scalar

657

Yield Stress of Multiphase Aggregate

Parameter

Forming Limit

Scalar

30

Forming Limit Parameter (FLP) = calculated major engineering strain / maximum major engineering strain

In addition to these standard results quantities, several Global Variable results can be created. Global Variables are results quantities where one value is representative of the entire model at a particular load increment. The following table defines the Global Variables which may be created depending on the Marc version as indicated also in the table.

Main Index

360 Marc Preference Guide Results Created in Patran

.

Global Variable Label

Main Index

Type

Description

Increment

Scalar

Increment of the analysis

Sub Increment

Scalar

Sub increment of the analysis

Time

Scalar

Time of the analysis

Buckling Mode

Scalar

Buckling mode number

Critical Load Factor

Scalar

Critical load factor for buckling analysis

Dynamic Mode

Scalar

Dynamic mode number from modal extraction

Frequency (radians/time)

Scalar

Frequency in radians per unit time for modal extraction

Process Pressure

Scalar

Process pressure at the end of the increment

Cycles

Scalar

Number of cycles (iterations) performed in the load increment

Separation

Scalar

Number of separations in the load increment

Cutback

Scalar

Number of load cutbacks performed in the increment

Splitting

Scalar

Number of increment splits performed in the increment

Total Volume

Scalar

Total volume of the model in the increment

Total Mass

Scalar

Total mass of the model in the increment

Total Strain Energy (>=2001)

Scalar

Total “total” strain energy at the end of the increment

Plastic Strain Energy (>=2001)

Scalar

Total plastic strain energy at the end of the increment

Creep Energy (>=2001)

Scalar

Total creep energy at the end of the increment

Kinetic Energy (>=2001)

Scalar

Total kinetic energy at the end of the increment

Damping Energy (>=2001)

Scalar

Total energy dissipated by dampers at the end of the increment

Total Work (>=2001)

Scalar

Total work by all external forces at the end of the increment

Thermal Energy (>=2001) Scalar

Total thermal energy (from Heat Transfer or Coupled analysis)

Total Elastic Strain Energy (>=2001)

Scalar

Total elastic strain energy at the end of the increment

Total Work by Contact Force (>=2001)

Scalar

Total work by contact forces at the end of the increment

Total Work by Friction Force (>=2001)

Scalar

Total work by friction forces at the end of the increment

Total Work by Springs (>=2001)

Scalar

Total work by spring forces at the end of the increment

Total Work by Foundations (>=2001)

Scalar

Total work by foundations at the end of the increment

Chapter 4: Read Results 361 Results Created in Patran

Global Variable Label

Description

Pos X Body_i

Scalar

X position of body i at end of increment

Pos Y Body_i

Scalar

Y position of body i at end of increment

Pos Z Body_i

Scalar

Z position of body i at end of increment

Pos Body_i

Scalar

Position (magnitude) of body i at end of increment

Angle Pos Body_i

Scalar

Angular position of body i at end of increment

Vel X Body_i

Scalar

X velocity of body i at end of increment

Vel Y Body_i

Scalar

Y velocity of body i at end of increment

Vel Z Body_i

Scalar

Z velocity of body i at end of increment

Vel Body_i

Scalar

Velocity (magnitude) of body i at end of increment

Angle Vel Body_i

Scalar

Angular velocity of body i at end of increment

Force X Body_i

Scalar

X force of body i at end of increment

Force Y Body_i

Scalar

Y force of body i at end of increment

Force Z Body_i

Scalar

Z force of body i at end of increment

Force Body_i

Scalar

Force (magnitude) of body i at end of increment

Moment X Body_i

Scalar

X moment of body i at end of increment

Moment Y Body_i

Scalar

Y moment of body i at end of increment

Moment Z Body_i

Scalar

Z moment of body i at end of increment

Note:

Main Index

Type

For Body Variables above which are treated as Global Variables, there is one for each contact body present in the model. To reduce the number of variables in problems with large number of contact bodies, only those variables that have all non-zero values are displayed or available.

362 Marc Preference Guide Direct Results Access

Direct Results Access Direct Result Access (DRA) is the default method (Method = Attach) of accessing results within Patran (or MSC.AFEA) via the Marc Preference. The results are not imported into the database but remain in the external results file. Only metadata (labels) are imported into the database. The results are accessed and extracted from the external file when needed during postprocessing. If a results file is moved or deleted the connection will be terminated and an error message to this effect is issued. As long as the results file remains attached, you never have to reattach it when opening/closing a database. In some instances with certain types of analyses using Marc, it is helpful to understand what DRA does and how to avoid problems. These are discussed below and basically fall into two categories: Rigid Geometry and Adaptive Meshing.

Rigid Body Animation Rigid geometry results that exist in the Marc results file contain translation and rotation information per increment. The rigid body NURB data (rigid geometry) can be imported into an empty database, but any translation or rotation of that rigid geometry is only visible, viewable, or able to animate within Patran under the following conditions: 1. In the CONTACT option in the input deck, the name and type of the contact body must always be specified. This is handled automatically if the input deck is written from the Marc Preference. However, input decks created from previous versions or other software programs may not have this data. Rigid bodies will not animate without the contact body name in the input deck, which gets translated into the results file. 2. A contact body LBC by the same name as the contact region in the results file also must exist in the database (under the Loads and BCs application). The names in the input file must be the same as the LBC definitions. This is automatic when the input deck is written from the Marc Preference. Also on import of the data from a results file into an empty database, these contact LBC names are automatically created for you. 3. The application region of a contact body LBC must be geometry and the geometric entities must exist. Again, under normal conditions this should be automatic even when importing into an empty database. 4. Angular rotation of the rigid body is based on the rotation reference point and rotation axis as defined in the rigid body contact LBC definition. If these are changed or deleted, the rotation will display incorrectly. By default these are the origin and x-axis if undefined. In summary, to have a rigid body animate, you must have run an input deck with the contact names as part of the CONTACT option and the contact LBCs in the database must have the same name with geometric entities associated. If you delete or modify your contact bodies, it is very likely that you will not be able to animate them. The rotation and translation is treated internally as global variables. There are two for each rigid body present representing the vector translation and the scalar angular rotation about a reference axis. These global variable thus change with load increment (or result case). Graph plots are possible with these data.

Main Index

Chapter 4: Read Results 363 Direct Results Access

Note:

Display of the deformed and undeformed rigid bodies can be handled using the Plot/Erase capability only. The Show Undeformed/Deformed toggles in the Results application do not work for rigid geometry.

Note:

Only the Attach method works for animating rigid geometry. If the rigid bodies are defined by a finite element mesh, they may still be animated as long as the application region of the rigid body defined in the database references geometric entities. The geometric entities will animate and not the elements. If you want rigid bodies defined using finite elements (line or patch data) to animate, you must Import the results into an empty database (not Attach).

Attaching Adaptive Meshing Results Adaptive meshing analyses require some understanding when attaching results. The safest thing to do when postprocessing an analysis where adaptive meshing has been requested, is to start with an empty database. Set the Object to Both, select the file, select the meshes and associated increments in the Translation Parameter form as shown above and press the Apply button. The meshes are imported into the database and the node/element IDs are offset automatically. When postprocessing through DRA, the proper mesh is displayed automatically whenever an associated load increment is selected in the Results application. This is all handled internally and should not require any user intervention. Each mesh that is imported is stored as an Patran group with specific names. If you delete these group names, then the postprocessing will not work correctly since the Results DRA application will not be able to post the proper mesh. If you do not attach a results file containing adaptive meshes to an empty database but attach it to the original database containing the original mesh then you must be aware of the following: • The Object should be set to Results Entities • If a jobname exists and you do not select a file before pressing Apply but the

jobname.t16/t19 file exists: 1. DRA automatically scans the file for meshes 2. You are asked if you wish to import results from all meshes including the meshes. If yes: Results for the 1st mesh are imported but not the mesh itself (assumes the original mesh is in the database - if you did an immediate remesh, this may not be true and you should start with a clean, empty database). All other meshes are imported into the database and the results associated to them according to the explanation given above. If no: Only the results of the first (original) mesh will be available. • If a jobname exists and you do select a file before pressing Apply

1. DRA by default selects all meshes and associated increments, which can be changed in the Translation Parameter form.

Main Index

364 Marc Preference Guide Direct Results Access

2. You are asked if you wish to import results from all meshes including the meshes. If yes: Results for the 1st mesh are imported but not the mesh itself (assumes the original mesh is in the database) unless this mesh was not selected in the Translation Parameters form. All other selected meshes are imported into the database and the results associated to them according to the explanation given above. If no: Only the results of the first (original) mesh will be available unless it was not selected in the Translation Parameters form in which case nothing will be available. • If the Object is set to Both or Model Data and you do or do not select a file but the

jobname.t16/t19 file exists: 1. DRA scans the file for multiple meshes 2. DRA imports all as the Object requested The problem with this scenario is that if a model already exists in the database, duplicate element/node errors will be issued.

Main Index

Chapter 5: Exercises Marc Preference Guide

5

Main Index

Exercises



Overview



Exercise 1 - Build a Cantilever Beam



Exercise 2 - A Simple Static Load



Exercise 3 - Buckling of a Fixed Pinned Beam



Exercise 4 - Cumulative Loading



Exercise 5 - A Simple Contact Problem



Exercise 6 - Nonlinear Material Plasticity



Exercise 7 - Contact with Velocity Control



Exercise 8 - Creep Analysis



Exercise 9 - Natural Frequency Analysis



Exercise 10 - Transient Dynamic Analysis



Exercise 11 - Frequency Response Analysis



Exercise 12 - Heat Transfer Analysis



Exercise 13 - Thermal-Mechanical Analysis

366 370

378 388

398 411 420 430

436 445 454 472

481 490

366 Marc Preference Guide Overview

Overview The purpose of this chapter is to give you an introduction to the Marc solver and how to set up and run problems in Patran (or MSC.AFEA) using the Marc Preference by guiding you through a series of interactive exercise problems. We provide various exercises that illustrate popular capabilities in the Marc solver. By completing the tutorial you will become familiar with using Marc and explore many of its capabilities. As you go through these exercises for the first time, concentrate on the process, rather than on the details of each step. As you become more familiar with Marc, you can return to these exercises to explore more details. Each example is meant to stand alone but we suggest that you start at the beginning and work your way through all of them. Throughout this tutorial you will conduct analyses of a simple cantilever beam. We have provided you with all of the steps required to build the cantilever beam model, apply the loads and boundary conditions, run the analyses and look at the results. Beginning in Exercise 1 - Build a Cantilever Beam, you will create the cantilever beam model. You will use eight, 2D plane stress elements. The elements are uniformly spaced along the length of the beam (i.e. a mesh eight elements wide and one element deep). Once you finish creating the beam model, you will save this database and use it for all subsequent exercises in this section.

Main Index

Chapter 5: Exercises 367 Overview

Note:

^ää=íÜÉëÉ=ÉñÉêÅáëÉë=~ëëìãÉ=óçì=~êÉ=ìëáåÖ=íÜÉ=ä~íÉëí=éêçÇìÅíáçå=ÅçÇÉ=çÑ=j~êÅK

Before You Begin

Exercise 1 - Build a Cantilever Beam, begins with the execution of Patran. Please consult the Basic Functions for instructions on starting Patran if you are completely unfamiliar with this process. We also assume that the Patran user settings (settings.pcl) are set to the default values. You will define all other non-default settings in the various exercises. This tutorial provides step-by step instructions for each of the exercises. You will come across commonly used commands and concepts in the order you will need them to create, analyze, and postprocess a model. As you proceed through the exercises, excerpts from the actual menus and forms you will see on your screen will help guide you through making the appropriate selections and providing the proper input. In Exercise 1 - Build a Cantilever Beam, you begin by creating a finite element model of a cantilever beam. You will save this model and use it as the starting point for the subsequent exercises. The rest of the exercises focus on applying loads, running analyses and viewing the results. These exercises demonstrate a number of analytical capabilities including linear and nonlinear statics, buckling, material plasticity, creep, natural frequency, transient dynamics and heat transfer, some with and some without contact.

Main Index

368 Marc Preference Guide Overview

During each step of the tutorial, rather than showing the entire Patran form, we use the following menu notations as shortcuts: Menu Bar Selections

The Menu Bar selections from the main form are pull-down menus. The following examples show our notation for referencing an item in a pull-down menu.

The menu item to the right of the slash (/) is the item you would select in the pull-down menu. Application Form Selections

From the main form you can select a particular Application form as shown in the following examples.

ì Geometry Action:

Create

Object:

Point

Method:

XYZ

ì Elements Action:

Create

Object:

Mesh Seed

Type:

Uniform

To enter an Application form, press the appropriate radio button on the main form as shown above. The items to the right of Action, Object, and Method are part of an option menu and they work the same way as a pull-down menu. User Input

The information that you enter, either through cursor picking or from the keyboard, is noted in green, such as in the following examples:

Main Index

Chapter 5: Exercises 369 Overview

New Database Name:

box_beam

Point Coordinates List:

[0 0 0]

Point List:

Point 1 2

Other Menu Notations

Apply

The Apply button instructs Patran to execute the form as you have filled it out. You can also undo the last form that Patran command, by pressing the Undo icon from the tool bar on the main form.

OK

The OK button is the same as Apply, except the form will automatically close or disappear.

Cancel Input Data...

The Cancel button will close and not execute the form. When a button or menu selection has three periods (...) following the name, as in the example below, it indicates that there is a subordinate form to follow.

Auto Execute

Many of the Application menu forms have an Auto Execute button. When activated, Auto Execute automatically executes the form when it has enough data. You may want to deselect this button if this is your first time using Patran.

Number of Elements

The square buttons, or toggles, such as in the examples below, are for selecting choices on the forms. Any number of these buttons may be pressed in.

Make Current Based on Model

ì 2 Point

Main Index

uu

3 Point

uu

4 Point

Unlike toggles, you can only select one diamond-shaped or circularshaped button, which is called a radio button, at a time.

370 Marc Preference Guide Exercise 1 - Build a Cantilever Beam

Exercise 1 - Build a Cantilever Beam Step 1: Open a New Database

Step 2: Define User Settings

Step 3: Create the Model Geometry

Step 4: Define the Finite Mesh Density

Main Index

Chapter 5: Exercises 371 Exercise 1 - Build a Cantilever Beam

Step 5: Create the Finite Element Mesh

Main Index

372 Marc Preference Guide Exercise 1 - Build a Cantilever Beam

Step 6: Create Material Properties

Step 7: Create Element Properties

Main Index

Chapter 5: Exercises 373 Exercise 1 - Build a Cantilever Beam

Main Index

374 Marc Preference Guide Exercise 1 - Build a Cantilever Beam

Step 8: Apply the Boundary Conditions

Main Index

Chapter 5: Exercises 375 Exercise 1 - Build a Cantilever Beam

Step 9: Create Groups

Main Index

376 Marc Preference Guide Exercise 1 - Build a Cantilever Beam

Step 10: Create the Interference Geometry

Step 11: Place the New Geometry in Groups

Main Index

Chapter 5: Exercises 377 Exercise 1 - Build a Cantilever Beam

Step 12: Close the Database

Main Index

378 Marc Preference Guide Exercise 2 - A Simple Static Load

Exercise 2 - A Simple Static Load In this exercise you will apply a static load to your cantilever beam model. Using large deformation theory you will analyze the model and review the results. In the second half of this exercise, you will repeat the analysis using small deformation theory. You will conclude this exercise by comparing the results for the small deformation analysis and the large deformation analysis. Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Step 3: Import the Old Database

Main Index

Chapter 5: Exercises 379 Exercise 2 - A Simple Static Load

Step 4: Post Only the Beam

Note:

You should always be aware of which is the current group. It is always listed in the header of the graphics screen after the database name and the viewport name.

Step 5: Create a Point Load

Step 6: Submit the Analysis

Main Index

380 Marc Preference Guide Exercise 2 - A Simple Static Load

Step 7: Monitor the Analysis

Main Index

Chapter 5: Exercises 381 Exercise 2 - A Simple Static Load

Step 8: Read the Results

Step 9: Postprocess the Results

Note that there is more than one results case and that the result case names are: Default Static Step,A1:Incr=n,Time=xx. This indicates that results are from the Default Static Step and that this is the 1st results file attachment (A1) and that this analysis job took n increments and each increment corresponds to a time. The total time of the analysis was specified to be 1.0 second. The total load was applied in n increments. Since this is a static analysis, the actual time is arbitrary and meaningless, but the total load was not applied until the last increment at 1.0 second. You should see a plot similar to this:

Main Index

382 Marc Preference Guide Exercise 2 - A Simple Static Load

Note:

Main Index

The plot you see on your screen is a true scaled version of the real deformation. You can toggle back and forth from a true (actual) deflection to a model relative scale by changing the Deformation Attributes on the Results application form. For most nonlinear applications with large deflections, True Scale must be used.

Chapter 5: Exercises 383 Exercise 2 - A Simple Static Load

Step 10: Run the Small Deflection Analysis

Step 11: Read in the Results of the Analysis

Main Index

384 Marc Preference Guide Exercise 2 - A Simple Static Load

Step 12: Postprocessing the Linear Analysis

With the Scale Interpretation still set to True Scale, you should have a plot similar to this:

Note:

Main Index

The maximum deflection of around 95 in. which is obviously completely unrealistic. See the discussion below.

Chapter 5: Exercises 385 Exercise 2 - A Simple Static Load

Linear Beam Theory Linear beam theory predicts the maximum beam deflection in the Ydirection and stress to be:

The maximum Y deflection of the beam can be taken directly off of the display spectrum/range. The largest value corresponds to a magnitude of around 95 in, which is in very close agreement with our hand calculation of 100 in. Linear beam theory assumes plane sections remain plane and the deflection is small relative to length of the beam. As you can clearly see, the deflection is very large and this analysis violates the underlying assumptions used for linear beam theory. These results match the linear hand calculations and also show that the small deformation assumption is not valid; therefore you need to perform the non-linear, large deformation analysis to obtain realistic results. In large deformation analysis, the bending and axial stiffness are coupled. As the cantilever beam deflects, a portion of the load, P, puts the beam in tension which tends to stiffen the beam in bending (i.e., geometric stiffness). Thus, you would expect to see a much smaller deformation in the large deformation analysis as compared to the small deformation analysis. Compare the values in the table below. Small Deflection

Large Deflection

Marc

~ -95 in

~ -60 in

Theory

-100 in

------

As you can see, the inclusion of large deformation effects are very important in realistically modeling the physical behavior of the cantilever model.

Main Index

386 Marc Preference Guide Exercise 2 - A Simple Static Load

Step 13: Additional Challenges

1. Use the Default Static Step and reset all of its defaults. In particular, use Large Displacement/Large Strain nonlinear geometric effects and change the Load Increment Parameters form to use a Trial Time Step Size of 0.1. Resubmit the analysis. Note the success or failure of the analysis (the exit status). An explanation of the exit status is always listed in the jobname.log file. 2. Try turning ON the Non-Positive Definite flag on the Solver Options form found under the Job Parameters and resubmit the job. Note the exit status. 3. Reset the Solver Options to the defaults. Modify the Default Static Step and change the convergence criteria under the Solution Parameters / Iteration Parameters form (set the Relative Residual Force to 0.01 from 0.1). Resubmit the job and note the exit status. 4. Reset all the parameters again and this time change the Solution Parameters / Load Increment Parameters. Change the Arclength Method from None to Modified Riks/Ramm. Resubmit the analysis and note the exit status. 5. Finally reset all the parameters again and this time change the Solution Parameters / Load Increment Parameters. Change the load Increment Type to Fixed. Try 10, 15, 20, and 30 increments in different runs. Exit status 2004 and 3002 are common problems encountered in nonlinear and contact problems. These indicate non-convergence within a particular load increment or numerical problems. There is not room enough in this manual to discuss all the scenarios that might cause this and their possible solutions but here are few things to try: 1. To force a solution, turn on the Non-Positive Definite flag. This sets up additional constraints to remove degrees of freedom that are causing a non-positive definite matrix. This can be dangerous if there really are modeling problems and you should check the results carefully. This is done under the Solver Options form in Job Parameters. 2. You can also force a solution by allowing the program to continue even though convergence has not be attained. This is done when creating a Load Step under Iteration Parameters in Solution Parameters. Turn ON the Proceed if not Converged toggle. Again, check your results carefully if you force a solution. 3. In some cases, the convergence criteria is too loose. For convergence based on residual forces, the default is 0.1 (maximum residual force divided by maximum reaction force). Sometimes a problem=åÉîÉê=êÉ~äáòÉë=íÜ~í=áí=áë=getting into trouble. Then once it is in trouble, it is too late. Changing the tolerance to a smaller value (say 0.01), causes the program to sense earlier that it needs to take more steps to converge. 4. By default, load incrementation for statics and dynamics is done with the AUTO STEP feature in Marc. If you use an Arclength method, the AUTO INCREMENT feature is used instead which is good for snap though type problems and detects instabilities.

Main Index

Chapter 5: Exercises 387 Exercise 2 - A Simple Static Load

5. Using a fixed increment scheme uses the AUTO LOAD feature of Marc. The program then takes even increments of the number specified. Sometimes this works and sometimes it does not. It may step over a numerical convergence problem or it may not, thus you do not know the best step size to use whereas AUTO STEP and AUTO INCREMENT figure this out automatically. 6. Finally, in this problem, if your problem is known to only be large displacement and not large strain, you should run it as such which avoids the problem altogether. Step 14: Closing/Quitting Patran

Main Index

388 Marc Preference Guide Exercise 3 - Buckling of a Fixed Pinned Beam

Exercise 3 - Buckling of a Fixed Pinned Beam In this analysis you will be determining the eigenvalue buckling load for a fixed/simply - supported beam. After running the analysis, you will compare these results to the theoretical prediction. Once again, you will use the model built in Exercise 1 - Build a Cantilever Beam for this analysis.

Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Step 3: Import the Old Database

Main Index

Chapter 5: Exercises 389 Exercise 3 - Buckling of a Fixed Pinned Beam

Step 4: Post Only the Beam

Step 5: Apply Additional Boundary Conditions

Main Index

390 Marc Preference Guide Exercise 3 - Buckling of a Fixed Pinned Beam

Main Index

Chapter 5: Exercises 391 Exercise 3 - Buckling of a Fixed Pinned Beam

Step 6: Add a Unit Compression Load

Main Index

392 Marc Preference Guide Exercise 3 - Buckling of a Fixed Pinned Beam

Step 7: Group Loads into Load Cases

Main Index

Chapter 5: Exercises 393 Exercise 3 - Buckling of a Fixed Pinned Beam

Step 8: Create Static and Buckling Analysis Load Steps

Note:

The difference between a load case and an analysis Load Step is only the amount of information they contain. A load case is only a collection of loads and boundary conditions (forces, displacements, contact, pressures, temperatures, etc.). The Load Step is a super set of the load case. A load case must be associated to a Load Step plus all the analysis setup parameters, output requests, solution type, etc.

Step 9: Submit the Buckling Analysis

Main Index

394 Marc Preference Guide Exercise 3 - Buckling of a Fixed Pinned Beam

Step 10: Monitor the Analysis

Main Index

Chapter 5: Exercises 395 Exercise 3 - Buckling of a Fixed Pinned Beam

Step 11: Read the Results

Step 12: Postprocessing the Results

The following plot should appear:

Main Index

396 Marc Preference Guide Exercise 3 - Buckling of a Fixed Pinned Beam

FEA Results The total buckling load is the eigenvalue multiplied by the applied load. In this case, the total applied load is 1.0 and the eigenvalue can be found on the results case name on the results form. P CR Z E ig en × P Appl ie d Z

The theoretical prediction for this case is: 2

π EI P CR Z -----------2 L′

C = A function of end constraint. For this case C = 2.05 L - Z 69.84 L′ Z ------C L L′ Z -------C 3

3

4 (1) ⋅ (2) bh I Z --------- Z ----------------------- Z 0.6667 i n 12 12 2

7

π ( 3.0 × 10 )P CR Z --------------------------------× 0.6667 Z 40470.84 2 ( 69.84 )

Compare the results=between the theoretical and finite element approach. The Eigenvalue is within six percent. Theoretical

Marc

40471

42907

Step 13: Closing/Quitting Patran

Main Index

Chapter 5: Exercises 397 Exercise 3 - Buckling of a Fixed Pinned Beam

Main Index

398 Marc Preference Guide Exercise 4 - Cumulative Loading

Exercise 4 - Cumulative Loading In the previous exercise we ran a buckling analysis which consisted of two separate analysis Load Steps. The first step was a static loading with a unit compression load. The second step performed the actual buckling analysis and determined the critical buckling as a factor of the unit compression load. The first analysis step was associated to a load case which contained the boundary conditions and the compression load. However the second step was associated with a load case that only had the boundary conditions. This exercise has been designed to help you understand how Marc deals with loads and the proper way to set them up in Patran.

In Marc, generally speaking, once a structure has been loaded, that load remains until it changes or is removed. So, in the previous exercise, the first step applied a unit compressive load. In the second step it appeared to have been removed. Although the physical load was not placed in the load case, that actual load level remained the same from the first step to the next. In order for that load to be removed, it would have had to have been explicitly taken down to zero. In this exercise we will set up and run two different static runs to illustrate how loads are handled. Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Main Index

Chapter 5: Exercises 399 Exercise 4 - Cumulative Loading

Step 3: Import the Old Database

Step 4: Post Only the Beam

Main Index

400 Marc Preference Guide Exercise 4 - Cumulative Loading

Step 5: Create a New Load Case

Main Index

Chapter 5: Exercises 401 Exercise 4 - Cumulative Loading

Step 6: Add a Mid-span Point Load

Step 7: Create Another New Load Case

Main Index

402 Marc Preference Guide Exercise 4 - Cumulative Loading

Step 8: Add a Tip Point Load

Step 9: Plot the LBC Markers

Main Index

Chapter 5: Exercises 403 Exercise 4 - Cumulative Loading

Step 10: Create an Analysis Load Step with Mid-span Load

Main Index

404 Marc Preference Guide Exercise 4 - Cumulative Loading

Step 11: Create an Analysis Load Step with Tip Load

Main Index

Chapter 5: Exercises 405 Exercise 4 - Cumulative Loading

Step 12: Submit the Analysis

Step 13: Monitor the Analysis

Main Index

406 Marc Preference Guide Exercise 4 - Cumulative Loading

Step 14: Read the Results

Step 15: Postprocessing the Results

The following plots should appear.

Main Index

Chapter 5: Exercises 407 Exercise 4 - Cumulative Loading

Step 16: Create Another New Load Case

Step 17: Turn Cumulative Loading Off

Main Index

408 Marc Preference Guide Exercise 4 - Cumulative Loading

Step 18: Read the Results

Main Index

Chapter 5: Exercises 409 Exercise 4 - Cumulative Loading

Step 19: Postprocess the Results

As expected, the first increment shows the result of the mid span load only. The second shows the results of the tip load only

Main Index

410 Marc Preference Guide Exercise 4 - Cumulative Loading

Main Index

Chapter 5: Exercises 411 Exercise 5 - A Simple Contact Problem

Exercise 5 - A Simple Contact Problem In this exercise we will create a simple interference for our cantilever beam to hit as it deflects. One of the many strength of Marc is its ability to solve complex contact problems. But perhaps even more importantly is its ability to easily set up these complex contact problems. Contact is treated as a nonlinear boundary condition. You define which contact bodies are rigid and which are defined as deformable. There is no necessity to define which contact bodies come in contact with which. There is no concept of a contact pair or master/slave definitions. By default all contact bodies can come in contact with each other and with themselves (excluding rigid to rigid of course).

Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Step 3: Import the Old Database

Main Index

412 Marc Preference Guide Exercise 5 - A Simple Contact Problem

Step 4: Post the Beam and Interference Geometry

Step 5: Create a Point Load

Step 6: Define the Deformable and Rigid Contact Bodies

Main Index

Chapter 5: Exercises 413 Exercise 5 - A Simple Contact Problem

Main Index

414 Marc Preference Guide Exercise 5 - A Simple Contact Problem

Note:

You can define rigid bodies with either Patran geometry or with finite elements. Geometry in the form of NURB curves or surfaces is actually written to the Marc input deck if geometry is selected. If a finite element mesh is selected or if geometry which has a mesh associated to it is selected, then the rigid body is written to the Marc as line segments or patches.

Step 7: Submit the Analysis

Step 8: Monitor the Analysis

Main Index

Chapter 5: Exercises 415 Exercise 5 - A Simple Contact Problem

Step 9: Read the Results

Step 10: Postprocess the Results

Main Index

416 Marc Preference Guide Exercise 5 - A Simple Contact Problem

The following plots should appear:

Note that something does not look right with these plots. It appears as if the beam is penetrating into the rigid body. This is due to the fact that the finite element model of the cantilever beam is too coarse. We need to refine the mesh around the area where contact is made. This can be accomplished in a couple of different ways. Marc has the ability to do local mesh refinement based on a number of criteria such as when nodes come into contact. Automatic mesh

Main Index

Chapter 5: Exercises 417 Exercise 5 - A Simple Contact Problem

refinement and global remeshing capabilities are available under the Translation Parameter form in Adaptive Meshing. If you wish to explore these capabilities, this is left as an optional exercise. For the purposes of this exercise we will manually refine the mesh.

Important: Clean up the graphics before proceeding. Press the Reset Graphics icon (appears as a broom). Step 11: Manually Refine the Mesh

Step 12: Associate the New Element to Surface 1

Main Index

418 Marc Preference Guide Exercise 5 - A Simple Contact Problem

Step 13: Detach the Results

Step 14: Resubmit the Results Again

Step 15: Read and Plot the Results Again

Main Index

Chapter 5: Exercises 419 Exercise 5 - A Simple Contact Problem

Step 16: Additional Challenge

Step 17: Closing/Quitting Patran

Main Index

420 Marc Preference Guide Exercise 6 - Nonlinear Material Plasticity

Exercise 6 - Nonlinear Material Plasticity In this exercise, you will be loading the cantilever beam so that it bends beyond its yield point. You will need to include plasticity as part of the material definition to accurately model this material behavior. First you will analyze the cantilever beam using the simplest material plasticity model, perfectly plastic. This material model assumes no hardening occurs after yield and it is useful for first order analysis. This plasticity model is also one of the most conservative models. After reviewing the results, this model will prove to be too conservative because a “Plastic Hinge” develops prior to reaching full load. You will then change the material plasticity model to an isotropic hardening model and rerun the analysis. This material model defines the true plastic strain versus true stress and tends to represent the material hardening more accurately.

Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Main Index

Chapter 5: Exercises 421 Exercise 6 - Nonlinear Material Plasticity

Step 3: Import the Old Database

Step 4: Post Only the Beam

Step 5: Create a Point Load

Main Index

422 Marc Preference Guide Exercise 6 - Nonlinear Material Plasticity

Step 6: Create a Plastic Material Constitutive Model

Main Index

Chapter 5: Exercises 423 Exercise 6 - Nonlinear Material Plasticity

Step 7: Run the Analysis

Step 8: Monitor the Analysis

Main Index

424 Marc Preference Guide Exercise 6 - Nonlinear Material Plasticity

Step 9: Read the Results

Step 10: Postprocessing the Results

Main Index

Chapter 5: Exercises 425 Exercise 6 - Nonlinear Material Plasticity

Note the level of stress at the fixed end relative to the 30,000 psi yield stress.

Step 11: Optional Challenge

Step 12: Model Isotropic Hardening

Main Index

426 Marc Preference Guide Exercise 6 - Nonlinear Material Plasticity

Step 13: Create a Graph

Main Index

Chapter 5: Exercises 427 Exercise 6 - Nonlinear Material Plasticity

Step 14: Edit the Material Properties

Step 15: Rerun the Analysis

Main Index

428 Marc Preference Guide Exercise 6 - Nonlinear Material Plasticity

Step 16: Read and Postprocess the Results

Step 17: Closing/Quitting Patran

Main Index

Chapter 5: Exercises 429 Exercise 6 - Nonlinear Material Plasticity

Note:

Main Index

In this exercise we defined a new material constitutive model within an existing material named steel. Material properties are part of the model definition. If associated to any element, all constitutive models will be translated and placed in the Marc input file. This means that if you were to try and rerun any of the previous exercises with this database, you would get the work hardening definition written to the input deck. This will cause result to differ from the original exercise. Constitutive models can be activated and deactivated. You should deactivate the plastic constitutive model if you wish to analyze a model without the plasticity or other constitutive models likewise. This is done under the Materials application using the Change Material Status... form.

430 Marc Preference Guide Exercise 7 - Contact with Velocity Control

Exercise 7 - Contact with Velocity Control In this exercise we will build upon the last two exercises and use the material nonlinear model created in Exercise 6 - Nonlinear Material Plasticity and the contact in Exercise 5 - A Simple Contact Problem. A second rigid body will be created that will push down the end of the beam using velocity control. By default, the analysis is one second. Therefore the amount of velocity prescribed in the vertical direction (-30 in/sec) is equivalent to the final prescribed position of this rigid body (-30 in.). Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Step 3: Import the Old Database

Step 4: Post the Beam and Rigid Bodies

Main Index

Chapter 5: Exercises 431 Exercise 7 - Contact with Velocity Control

Step 5: Define the Plastic Constitutive Model

Step 6: Define the Deformable and Rigid Contact Bodies

Main Index

432 Marc Preference Guide Exercise 7 - Contact with Velocity Control

Step 7: Refine the Mesh in the Contact Area

Main Index

Chapter 5: Exercises 433 Exercise 7 - Contact with Velocity Control

Step 8: Associate the New Element to Surface 1

Step 9: Submit the Analysis

Main Index

434 Marc Preference Guide Exercise 7 - Contact with Velocity Control

Step 10: Monitor the Analysis

Step 11: Read the Results

Step 12: Postprocess the Results

Main Index

Chapter 5: Exercises 435 Exercise 7 - Contact with Velocity Control

The following plots should appear:

Step 13: Closing/Quitting Patran

Main Index

436 Marc Preference Guide Exercise 8 - Creep Analysis

Exercise 8 - Creep Analysis In this exercise, the loading history consists of two steps. In the first step, you will extend the cantilever beam non-linearly under an enforced displacement. In the second step, you will change the analysis to a creep analysis. In this step, you will allow the cantilever beam to creep for 20 seconds. The second step will cause the stress in the beam to “relax.”

Step 1: Do Exercise 1 - Build a Cantilever Beam

Step 2: Open a New Database

Step 3: Import the Old Database

Main Index

Chapter 5: Exercises 437 Exercise 8 - Creep Analysis

Step 4: Post Only the Beam

Step 5: Create a Creep Property

Main Index

438 Marc Preference Guide Exercise 8 - Creep Analysis

Note:

The exponent of time could have been input as 1.0. The reason: namely one is entering . Now we really want epsilon dot . So the program takes the derivative and one gets epsilon dot = A * n * t(n-1). So if n=0.0, one has an identically zero strain rate, hence no relaxation. Thus n must be entered as 1.0 or left blank.

Step 6: Create a New Load Case

Step 7: Create the Enforced Displacement

Main Index

Chapter 5: Exercises 439 Exercise 8 - Creep Analysis

Step 8: Create Analysis Load Steps and Submit the Job

Create the second step, start by changing the Job Step Name.

Main Index

440 Marc Preference Guide Exercise 8 - Creep Analysis

Step 9: Monitor the Analysis

Step 10: Read the Results

Main Index

Chapter 5: Exercises 441 Exercise 8 - Creep Analysis

Step 11: Postprocess the Results

Repeat this step for the time increment at t=21 seconds. Note the relaxation of the stress. The following plots should appear:

Step 12: Plot the X Component of Stress with Time

Main Index

442 Marc Preference Guide Exercise 8 - Creep Analysis

The following graph should appear. The initial loading from time T=0 to time T=1.0 represents the nonlinear static ramp of the load. At times greater than 1.0, the curve represents the creep loading which represents the stress relaxation.

Step 13: Additional Challenge

Main Index

Chapter 5: Exercises 443 Exercise 8 - Creep Analysis

Step 14: Closing/Quitting Patran

Main Index

444 Marc Preference Guide Exercise 8 - Creep Analysis

Main Index

Appendix A: Supported Keywords Marc Preference Guide

A

Main Index

Supported Keywords



Parameter Cards



Model Definition



History Definition

500 502 508

500 Marc Preference Guide Parameter Cards

Parameter Cards The following Marc Parameter Cards are supported. For further information about these options see the Marc Program Input Manual (Volume C). Keywords supported on import (r=read) and export (w=write) are indicated. Command

Pages

ADAPTIVE (w)

page 205

ASSUMED (w)

page 184

BEAM SECT (r/w)

page 136

BUCKLE (w)

page 240, page 266, page 313

CENTROID (w)

page 264

CONSTANT (w)

page 184

CREEP (w)

page 249

COUPLE (r/w)

page 232 - written for for any Coupled analysis solution.

DYNAMIC (w)

page 238, page 242, page 264, page 266, page 313

ELASTIC (r/w)

page 205, page 234 - written for multiple back substitutions or for local

remeshing of a linear analysis when no load increments specified. ELASTICITY (w)

page 205, page 264- automatically written for remeshing and elatomeric

materials. Total lagrange flagged if beam, shell, or plane stress elements. END (r/w)

page 199, automatically written.

EXTENDED=(r/w)

page 184

FINITE (w)

page 234, page 242, page 264

FOLLOW FOR (w)

page 29, page 234, page 242

HARMONIC (w)

page 245

HEAT (r/w)

page 147, page 151, page 256, page 259

LARGE DISP (w)

page 234, page 242, page 245, page 247, page 264

LINEAR (w)

None - written when needed.

LUMP (w)

page 184

MPC-CHECK (w)

page 189

NO LOADCOR (w)

None - written automatically for linear problems.

PLASTICITY (w)

page 205, page 264 - sometimes necessary for remeshing using elastic-

plastic meterials and with use with Herrmann elements. PROCESSOR (w)

Main Index

page 334 - written for single file DDM jobs if alternate Metis methods used

RADIATION (w)

page 225

RESPONSE (w)

page 247

Appendix A: Supported Keywords 501 Parameter Cards

Command

Main Index

Pages

REZONING (w)

page 205 - written automatically for Global Adaptive Meshing.

RBE (w)

page 36 - written automatically when RBE2/3 present.

SCALE (w)

page 266

SETNAME (w)

page 201

SHELL SECT (w)

page 322

SIZING (w)

page 189 - generally written automatically.

SPFLOW (w)

page 308

STOP (w)

page 22, page 25, page 182

TABLE (r/w)

page 47, page 49, page 184

TITLE=(w)

page 182

TSHEAR (w)

page 136, page 150- written only for elements 22, 45, 75, 140.

UPDATE (w)

page 234, page 242, page 264

VERSION (w)

page 184

502 Marc Preference Guide Model Definition

Model Definition The following Marc model definition cards are supported. For further information about these options see the Marc Program Input Manual (Volume C). Keywords supported on import (r=read) and export (w=write) are indicated. Keyword

Pages

ADAPTIVE (w)

page 205

ANISOTROPIC (r/w) (Mechanical)

page 74

ANISOTROPIC=(r/w) (Thermal)

page 74

ARRUDABOYCE=(r/w)

page 86

ATTACH EDGE (w)

page 186

ATTACH ELEMENT (w)

page 186

ATTACH FACE (w)

page 186

ATTACH NODE (w)

page 205, page 186

AXITO3D (w)

Marc 2003 only. Uses PRE STATE otherwise.

page 158, page 305

BUCKLE INCREMENT (w)

page 279

CHANGE STATE=(w)

page 53, page 302

COMPOSITE=(w)

page 110

CONNECTIVITY (r/w)

page 33, page 203, page 316

CONTACT=(r/w)

page 64, page 191, page 193, page 195, page 198, page 252

CONTACT NODE(w)

page 65

CONTROL (w) (Stress)

page 256, page 264, page 287

CONTROL=(w) (thermal analysis)

page 256

COORDINATES=(r/w)

Main Index

Comments

All nodes are written relative to page 32, page 203, page 316 the global coordinate system except if the CYLINDRICAL keyword is used.

CRACK DATA (w)

page 105

CREEP=(r/w)

page 93, page 249

CURVES (w)

page 228

CYCLIC SYMMETRY(w)

page 228

Appendix A: Supported Keywords 503 Model Definition

Keyword CYLINDRICAL=(r/w)

Comments For nodes listed in this option, nodal input (COORDINATES) and output (displacements, etc.) are given in this coordinate system.

page 31, page 32

DAMAGE (w)

page 103

DAMPING (r/w)

page 93, page 279

DEFINE=(sets)=(r/w)

page 201, page 190

DENSITY EFFECTS (w)

page 107

DIST FLUXES=(r/w)

page 60

DIST CHARGE=(w)

Must use Table format

page 63

DIST CURRENT=(w)

Must use Table format

page 63

DIST LOADS=(r/w)

Can not put load on 1D elements.

page 52, page 55

END OPTION=(w)

Written automatically.

page 199

ERROR ESTIMATES(w)

page 316

EXCLUDE(w)

page 65

FAIL DATA=(r/w)

UFAIL not currently supported. Currently only one failure criteria supported.

page 85

FILMS (r/w)

Film coefficient and sink temp index not supported.

page 59

FIXED ACCE=(r/w)

page 49

FIXED DISP=(r/w)

page 49

FIXED EL-POT=(w)

Must use Table format

FIXED TEMPERATURE= (r/w) FIXED VOLTAGE=(w)

Main Index

Pages

page 63 page 53

Must use Table format

page 63

FOAM=(r/w)

page 86

FORMING LIMIT (w)

page 105

GAP DATA=(w)

page 144

GASKET=(w)

page 123, page 151

GENT=(r/w)

page 86

504 Marc Preference Guide Model Definition

Keyword

Comments

GEOMETRY=(r/w) GLOBALLOCAL (w)

page 136, page 150

Marc 2005 or higher.

page 305

GRAIN SIZE(w)

page 106

HYPOELASTIC (w)

page 89

INITIAL DISP=(w)

page 56

INITIAL PC (w)

page 106

INITIAL POROSITY(w)

page 106

INITIAL STATE=(r/w)

page 81, page 302

INITIAL TEMP=(w)

Only one degree-of-freedom supported.

page 61

INITIAL VEL=(w)

page 56

INITIAL VOID RATIO (w)

page 106

INSERT=(w)

page 147, page 151

ISOTROPIC (r/w) (Stress)

page 74

ISOTROPIC (r/w) (Heat Transfer)

Main Index

Pages

ISOTROPIC,THERAL used for Joule heating.

page 74, page 108

ISOTROPIC,ELECTROSTA= Must use Table format (r/w) (Electrostatic)

page 108

HYPOELASTIC (w)

page 89

Requires use of user subroutines.

LOADCASE (w)

page 48

MASSES=(w)

page 136

MATERIAL DATA (w)

page 106

MODAL INCREMENT (w)

page 279

MOONEY=(r/w)

page 86

NO PRINT (w)

page 316

NODAL THICKNESS=(w)

page 136, page 150

OGDEN=(r/w)

page 86

OPTIMIZE=(w)

page 189

ORIENTATION=(r/w)

page 150

ORTHO TEMP (r/w)

page 81, page 94, page 101, page 172

Appendix A: Supported Keywords 505 Model Definition

Keyword

Pages

ORTHOTROPIC=(r/w) (Mechanical)

page 74

ORTHOTROPIC (r/w) (Thermal)

page 74

PHI-COEFFICIENTS (r/w)

page 86

POINT FLUX=(w)

Only one degree-of-freedom supported.

page 61

POINTS=(w)

page 186

POINT CHARGE=(w)

page 63

POINT CURRENT=(w)

page 63

POINT LOAD=(r/w)

page 51

POINT TEMP=(w)

page 53

POST=(w)

page 203, page 313, page 266

POWDER (w)

page 107

PRE STATE (w)

Main Index

Comments

Marc 2005 or higher.

page 305

PRINT ELEMENT=(w)

page 316

PRINT NODE=(w)

page 316

PROPORTIONAL INCREMENT=(w)

page 279

RBE2 (w)

page 36

RBE3 (w)

page 36

REAUTO=(w)

page 203

REBAR=(w)

page 147, page 151

RELATIVE DENSITY (w)

page 107

RESPONSE SPECTRUM=(w)

page 247

RESTART=(w)

page 203, page 266

RESTART LAST=(w)

page 203

ROTATION A=(w)

page 55

SCALE=(w)

Only for Small Strains, Small page 266 Displacement - Static analysis.

SERVO LINK=(w)

Explicit MPCs and Sliding Surfaces defined by this keyword option.

page 36, page 43

506 Marc Preference Guide Model Definition

Keyword

Comments

SHAPE MEMORY(w)

page 102

SHIFT FUNCTION (w)

page 90

SOIL (w)

page 106

SOLVER=(w)

page 189, page 287

SPECIFIC WEIGHT (w)

page 106

SPLINE=(w)

page 65

SPRINGS=(r/w)

page 123, page 136

SURFACES (w)

page 205, page 186

STRAIN RATE (r/w)

page 96, page 101, page 176

TABLE (w)

Only writen for Marc 2003 or higher.

page 47, page 49, page 136, page 151, page 170, page 184, page 252 page 81, page 94, page 96

TEMPERATURE EFFECTS (r/w)

Main Index

Pages

page 64

THERMAL CONTACT (w)

See CONTACT.

TRANSFORMATION=(w)

page 31,page 32 Displacement and loads or reactions are output relative to the transformed systems for the specified nodes. Transformations should not be applied to nodes that can come into contact with either a rigid or deformable body.

TYING=(w)

Support for types 1-6, 26, 31, 32, 33, 34, 49, 50, 52, 53, 80, 100, and 102-506. TRANSFORMATION not recommended for nodes involved in TYING types.

page 36 to page 42

UCONTACT=(w)

page 222

UFRIC=(w)

page 222

UHTCOE=(w)

page 222

UHTCON=(w)

page 222

UMOTION=(w)

page 222

UORIENT=(w)

page 150, page 151, page 154

VELOCITY=(w)

page 53

Appendix A: Supported Keywords 507 Model Definition

Keyword

Main Index

Comments

Pages

VIEW FACTOR (w)

page 61, page 225

VISCEL EXP (r/w)

page 90

VISCELMOON=(r/w)

page 90

VISCELOGDEN=(r/w)

page 90

VISCELORTH=(r/w)

page 90

VISCELPROP=(r/w)

page 90

WORK HARD=(r/w)

page 96, page 101, page 172

508 Marc Preference Guide History Definition

History Definition The following Marc history definition cards are supported. For further information about these options see the Marc Program Input Manual (Volume C). Keywords supported on import (r=read) and export (w=write) are indicated. Command

Main Index

Pages

ACC CHANGE=(w)

page 49

ACTIVATE (w)

page 190

APPROACH (w)

page 252

AUTO CREEP (w)

page 249, page 266, page 278

AUTO INCREMENT (w)

page 266, page 287, page 266

AUTO LOAD (w)

page 249, page 266, page 279

AUTO STEP (w)

page 287, page 266, page 271

AUTO THERM (w)

page 266, page 302, page 276

AUTO THERM CREEP (w)

page 266, page 302, page 276

AUTO TIME

Not supported.

BUCKLE (w)

page 240, page 264

CHANGE STATE (w)

page 53, page 302

CONTINUE (w)

page 242

CONTACT TABLE (w)

page 64, page 291

CREEP INCREMENT (w)

page 249, page 279

DEACTIVATE (w)

page 300

DISP CHANGE=(w)

page 49

DIST FLUXES=(w)

page 60

DIST LOADS=(w)

page 52, page 55, page 308

DYNAMIC CHANGE=(w)

page 242, page 279, page 264, page 266, page 279

FILMS=(w)

page 59

HARMONIC (w)

page 245

LOADCASE (w)

page 48, page 312

MODAL SHAPE (w)

page 238, page 242

MOTION CHANGE (w)

page 64, page 252

POINT FLUX (w)

page 61

POINT LOAD=(w)

page 51

POST INCREMENT (w)

page 313

Appendix A: Supported Keywords 509 History Definition

Command

Main Index

Pages

PRINT ELEMENT (w)

page 316

PRINT NODE (w)

page 316

PROPORTIONAL INCREMENT (w)

page 266, page 279

RECOVER (w)

page 238, page 264, page 234

RELEASE=(w)

page 291

RELEASE NODE(w)

page 50

SOLVER=(w)

page 287

SPECTRUM=(w)

page 247

STEADY STATE (w)

page 264

SUMMARY (w)

page 316

SUPERPLASTIC (w)

page 308

SYNCHRONIZE (w)

page 252

TEMP CHANGE (w)

page 53

TIME STEP (w)

page 234, page 264, page 252

TRANSIENT=(w)

page 256, page 259

VELOCITY CHANGE=(w)

page 53

510 Marc Preference Guide History Definition

Main Index

Appendix B: Transition Guide Marc Preference Guide

B

Main Index

Transition Guide

512 Marc Preference Guide Overview

Overview This appendix lists a few guides and suggestions for users transitioning from other analysis codes. The intention of this document is to ease the transition primarily from ABAQUS or the discontinued Patran Advanced FEA product to Marc when doing nonlinear finite element analysis with Patran as the pre/postprocessor. There are four parts: • Introduction and New Features Section • Summary - purpose is to alert you to the main points you need to know to avoid having problems

and give enough information that an experienced user will not need to read the Reference Section • Reference Section - gives usage details of topics referred to in the first sections • Resolving Convergence Problems - that you may encounter when doing non-linear analyses with

Patran and Marc (or MSC.AFEA).

Capabilities and Features The Marc Preference supports all of the nonlinear analysis capabilities that the ABAQUS Preference does (and the discontinued Patran Advanced FEA did), plus a lot more. Capabilities never previously supported or limited in these and other Preferences include: • Structural, thermal, and coupled thermal-mechanical analysis • Multi step analysis • Global and local adaptive re-meshing - including results visualization • Full 3D deformable body contact • Multi-body contact (very easy setup) - plus contact tables • Contact of higher order elements, • Rigid geometry contact including symmetry planes • Analytical and discrete definitions of rigid and deformable contact • Hour glass control for reduced integration elements • Generalized plane strain elements • User control over convergence criteria • Multiple solver options • Direct Results Access (DRA) - results remain in result file. • Rigid geometry results visualization/animation • Input deck reader • User subroutine access • Superplastic forming analysis • Cyclic symmetry

Main Index

Appendix B: Transition Guide 513 Overview

• Axisymmetric to 3D capabilities • Radiation view factor calculations • Activation/de-activation of elements • Conversion of models from other Preferences (solvers) • Material (elastomer) experimental data fitting • Domain decomposition - parallel processing • Beam library • Rebar modeling plus rebar elements • Boundary conditions on geometry - in the analysis input deck • Improved user interface - with one or two button click you can: • Run a default nonlinear analysis - after model is created • Monitor analysis - including viewing status files • View or edit and re-submit input deck • Read results - postprocess deformed shape • And much, much more!

Model Conversion Model/Database Conversion: The Patran Advanced FEA Preference no longer exists and has been discontinued. When and old database is opened in Patran 2001 and later releases, all Patran Advanced FEA data is automatically converted to the Marc Preference. The databases are converted with Patran’s normal Preference switching code, which means that only nominal information is converted to the Marc model. Be sure to save copies of your databases. A capability has been implemented in Patran 2001 r2a that significantly increases the complexity level of the model information converted during Preference switching. This capability converts nearly all data from previous (ABAQUS -based) models to the Marc preference. This can be used for all analysis Preferences (if appropriate mapping tables are available) including full model conversion from other solvers such as MD Nastran, MSC.Dytran, ANSYS, LSDYNA 3D, etc. You turn this new capability on in Patran under Preferences | Analysis. Users should always check converted models for accuracy and completeness. See the Reference Section for more details on customization (i.e., user control of mapping) and using this new capability with other Preferences. Note that the ABAQUS input file reader can be accessed via the ABAQUS Preference to import these model and then switch the Preference to Marc.

Main Index

514 Marc Preference Guide Overview

Defaults Consider using these Analysis form defaults (either edit the default static step of the existing template.db, or create a new template.db) for more ABAQUS like defaults: • Load Increment Parameters • Change the Time Step Scale Factor from 1.2 to 1.5 (or even 2.0; using smaller values will

slow down convergence and may even cause the analysis to exceed the maximum # of cutbacks allowed before decreasing the time step sufficiently). • Set the Trial Time Step Size to 0.1 (the default of 0.01 causes more increments and larger

files than necessary for models that converge easily and the automatic time stepping will cut back if necessary). • Set the Minimum Time Step to 0.0001 (this typically is the stopping criteria the way it is for

ABAQUS, if you do not do this the default stopping criteria of Max # of Cutbacks is used, which is not as easy to define a meaningful number for). • Set the Max. no. of Steps to 50 (or 100, it defaults to 20 which often isn't enough). • Turn Quasi-Static Inertial Damping ON and make sure to include a material density • On some problems it may be helpful to tighten the Relative Residual Force under Iteration

Parameters from 0.1 to 0.01. Note that the translator turns the new Autoswitch capability ON by default (when near 0 residual is detected it automatically changes to a displacement criteria) • Be sure to use Adaptive load increment type with Arc Length Method set to None • Job Parameters • Consider changing the Bias on Contact Distance Tolerance (found under Analysis |

Analyze | Translation Parameters |Contact Control Parameters |Contact Detection) value to 0.5 or 0.9 as the default. If you run into contact-related convergence problems this is one of the first things to try. • This last recommendation is somewhat controversial, but you will avoid convergence

problems in some cases by turning ON Non-Positive Definite under Translation Parameters | Solver Options. If you have a run that will not converge, this is one of the first things to try (see section on , 520 for more suggestions).

Nomenclature • ABAQUS incompatible modes = Marc assumed strain • ABAQUS hybrid = Marc Herrmann element

(requires constant volume formulation) • Status files:Marc jobname.stsABAQUS jobname.sta • Input files: Marc jobname.datABAQUS jobname.inp

MD Nastran jobname.bdf

Main Index

Appendix B: Transition Guide 515 Overview

• Output file: Marc jobname.outABAQUS jobname.dat

Patran Advanced FEA jobname.msg MD Nastran jobname.f06 file • Results Files:Marc jobname.t16ABAQUS binary jobname.fil

MD Nastran jobname.xdb Marc jobname.t19ABAQUS ascii jobname.fil

Material Properties This is nearly identical including the requirement to use true stress vs log-plastic strain to define hardening behavior of elastic-plastic materials. If utilities have been installed, Utilities | Fields | Modify | Material Field automates converting from engineering stress-strain to true stress - log plastic strain. Experimental curve-fitting for elastomers is supported. Note that Ogden hyperelastic coefficients are different in Marc and ABAQUS.

Element Properties Marc has all the same element formulations and options plus a few more. The labels and data input for comparable element types is similar. Marc has all of the same element formulations and options as ABAQUS plus a few more (such as generalized plane strain and semi-infinite). One difference is that the Assumed Strain (Abaqus’ Incompatible Modes) and Constant Volume options in the Marc Preference are specified on the Input Properties form rather than via a pull-down menu option. Marc beam orientation vector should be a vector in the beam XY plane (like MD Nastran) where ABAQUS beam orientation vector is given as the perpendicular to the beam XY plane. Abaqus axisymmetric models are built in the global XY plane with X = radial, Y = axial, and Z = meridonal (hoop) direction. Marc axisymmetric models are also built in the global XY plane, but are different in that X = axial, Y = radial (think of the way you would lay out a jet engine where X is the station), and Z = hoop. To convert ABAQUS axisymmetric models to Marc: 1. Create a group with all entities 2. Use Group | Transform | Mirror to mirror the model about the Y-Z plane, i.e., select Coord 0.1 under Define Mirror Plane Normal. Make sure to select the toggles that transform all LBC's and element propterties with the model and flip the elements if necessary to keep the element normals in the positive Z direction. 3. Use Group | Transform |Rotate and rotate the model minus (-)90 degrees about the Z-axis. The Marc work-horse shell element is the Thick Shell (element 75), so this element should be used for most shell applications even though the default may be Thin Shell.

Main Index

516 Marc Preference Guide Overview

Load/Boundry Conditions (LBC's) This is nearly identical in that all loads and displacements are total values (not incremental). The major difference is in setting up contact (which is actually much easier to do). Patran does not support pressure loading on 1-D elements, but you can use the LBC option CID Distributed Load to create pressure loads on 1-D elements, including axisymmetric shells. One difference is in the way removal of LBC sets is handled. ABAQUS removes LBCs gradually over the subsequent step, easing convergence problems. The Marc Preference has this capability when defining contact tables. If you remove a force, pressure, inertial load, or displacement, the LBC will be removed suddenly at the beginning of the step and may cause convergence problems if you have not specifically set up your contact table to do otherwise. If you do not use the contact table but still want the load removed gradually, you can include the LBCs in the subsequent step with zero values so their effect will be removed gradually over the load step. One thing to be aware of though, sometimes Patran fails to include some types of LBCs that have zero as the value. In this case, a work around is to put in a very small number but not zero. If local cylindrical (or spherical) coordinate systems (c.s.) are required for material and element property orientation usage they must be created manually. In other words, selecting a local cylindrical system on the element property form for material orientation will NOT work the same way as it does for the ABAQUS Preference because the Marc CYLINDRICAL option only applies to nodal quantities. The workaround is to reference the local cylindrical system under the Orientation System input data box, and then reference a spatial field in the Orientation Angle box where the spatial field simply gives the angle in degrees of the element centroid relative to the cylindrical system. Since Patran cylindrical systems give theta in radians, and the rotation angle of the ORIENTATION option is in degrees, this requires a spatial field using the cylindrical system with theta as the only active independent variable and mapping values from 0 to 360 as theta goes from 0 to 2*PI. ABAQUA uses contact pairs (consisting of two application regions) where a master region can see and prevent penetration of the nodes on the slave region. For contact pair contact Patran puts circle markers on the slave surfaces and arrow markers (pointing toward the slave region) on the master surfaces. For Marc contact Patran puts circle markers on deformable body surfaces and arrows pointing inward on the meshed rigid bodies, and puts hash marks on the inner side of rigid geometry curves. Marc allows geometry to be used to define the rigid body, but does NOT allow tria shells to be used to define the rigid body (only quads) if the geometry is meshed. In ABAQUS you typically have to move the contact regions together, but do not need to do this in Marc. In Marc you can give the rigid body an Initial Velocity in the desired direction to move them together. Marc uses contact body contact (which can include self-contact), where each body is created as a separate application region and contact between the bodies is characterized in the Contact Table. The Contact Table assumes that all bodies will be prevented from penetrating (defined as Touching) all other bodies (including itself), but the contact table and the contact parameters can be modified under Analysis | Step Creation | Solution Parameters | Contact Table. It is located under Step Creation because the contact table can change between analysis steps. Marc's contact body interaction still uses contact pair algorithms, so to avoid penetration follow the same master/slave rules which are to give the lower contact body number to the body with: 1) the finer mesh; 2) the softer material; 3) a convex corner or edge.

Main Index

Appendix B: Transition Guide 517 Overview

Marc's contact boundary detection algorithms are very fast, so it is not a problem to just select the entire body and let Marc figure out the specific regions that will see other bodies. The only problem with doing this is also the most common problem you will have when running contact jobs, and that is the limitation that you cannot apply a displacement constraint to any node that may come into contact. When a node with a constraint comes into contact Marc will give you an error about illegal tieing constraints. One way around this problem when using symmetry in your problem is to use rigid body symmetry planes to define the symmetry conditions (as opposed to defining symmetry conditions with displacement constraints). Another limitation is that nodes that may come into contact should not reference a local coordinate system as their analysis CID. If this happens Marc will stop with a 2011 exit message (version 2001 and prior) or give a warning that the analysis CID has been changed. You can speed up the contact calculations by using the contact table to eliminate checking of bodies that you know will never touch. Points to Remember: If you are comfortable with Patran and ABAQUS, make sure to get the latest versions of Patran and Marc. Prior versions have too many differences to allow an easy transition. If you must use an older version see FAQ #3 in the Reference Section for suggestions. Make sure P3_TRANS.INI (Windows) or site_setup (UNIX) file points to the appropriate Marc version so you can automatically submit Marc jobs from within Patran. If you need more information than is found in this document there are two training courses that will provide all the information you will need: PAT 322 is a course covering MSC.AFEA and MAR 120 a course covering Patran /Marc.

Reference Section Database Conversion: The capability previously mentioned is new to Patran 2001 r2a and will significantly increase the complexity level (and give the user some control in addition) of the model information that is successfully converted during Preference switching between any Preference in the database. This capability should allow easier Preference switching of all solvers such as from ANSYS to MD Nastran, or MD Nastran to Marc (and vice-versa), or MD Nastran to MSC.Dytran, etc. While this capability allows almost all of the model information (including contact, where there are significant differences) to be converted, there are mapping tables. Users should also check these converted models for accuracy and completeness. Users should check the MSC website for updates to these tables. Make sure to save copies of your earlier databases so they can be converted again when and if updated/improved mapping tables become available. When opened, old databases containing the discotinued Patran Advanced FEA Preference are automatically converted to the Marc Preference. Contact Interaction: As previously discussed, Marc uses contact body contact (which can include rigid bodies), where each body is created as a separate application region and contact between the bodies is characterized in the Contact Table. The contact table is a matrix with entries consisting of Touching, Glued, or Null. The defaults assume that all bodies will be prevented from penetrating (defined as Touching) all other bodies (including itself), but the contact table and the contact parameters can be modified under Analysis | Load Step Creation | Solution Parameters | Contact Table. The contact table is located under Load Step Creation because it can change between steps. Patran puts circle markers on deformable body surfaces and arrows pointing inward on the meshed rigid bodies, and puts hash marks on the inner side of rigid geometry curves.

Main Index

518 Marc Preference Guide Overview

Marc master-slave contact interaction is defined by the parameters Contact Distance Tolerance, Bias Factor, and Seperation Force (can also use stress). The defaults for all contact bodies are defined on the Analysis | Job Parameters | Contact Parameters | Contact Detection form, but the values for individual contact pairs can be specified as part of the contact table. Master-slave contact interaction is described in the following figures. In this case the rigid body is the master and the deformable body is the slave. In the case of deformable-deformable contact the body created first (listed first in the contact table) is the master.

Figure B-1

Contact Procedure

No contact is assumed as long as the deformable body does not come within the contact region (zones 2,3). Marc detects contact when the deformable body falls in the contact region (cases 2, 3 in Figure B-2) and applies a seperation force to prevent the bodies from pulling apart and the contact condition is defined as closed. This same contact interaction model is used for deformable to deformable body contact where the master body is the one that comes first in the contact table. As mentioned previously, contact interaction is defined by the parameters Contact Distance Tolerance, D, (see Figure B-1 - by default Marc uses 1/20th of the element edge length), Bias Factor, B (see Figure B-2 - Marc default on this is 0 but you can override this value on the Analysis | Job Parameters | Contact Parameters - Contact Detection form) and Seperation Force. The bias factor offsets the contact region as shown in Figure B-2.

Main Index

Appendix B: Transition Guide 519 Overview

Figure B-2

Contact with Bias Factor

Note that in the case of contact penetration ( i.e., the node moves past the contact zone), the increment will split (if allowed). Splitting is when the load increment, which relates to the amount of penetration, is reduced until the node falls in the contact zone. If there is a problem with chattering (a condition where a particular node jumps into and out of contact thus preventing the increment from converging), you can go to Job Parameters | Contact Control Parameters | Seperation and set the Chattering toggle to Suppress. If you suppress chattering Marc will simply ignore this node after a few cycles of opening/closing. Marc has a Glued contact option that is similar to ABAQUS tied contact. By defining two bodies as glued, slave nodes cannot penetrate, separate, or slide relative to the master surface. If glued contact is activated both the normal and tangential displacement of the node are constrained. It can be used for bonding surfaces together permanently and is frequently used for mesh refinement purposes. Bodies to be glued together are defined by a G on the contact table. By using glued contact and specifying a small separation force a condition of infinite friction can be modeled. Prior Marc versions required the user to specify a large separating force but the default in Version 2001 and beyond is that separation is not allowed. A capability was added in Marc 2001 to do stress-free initial contact. This capability is available in ABAQUS using the Initial Adjustment Tolerance on the Rigid - Deformable LBC form. Using this option in Marc, any slave node that falls within the contact zone defined by the Contact Distance Tolerance is projected to lie on the master surface such that any gaps or overlaps present in the initial model will not introduce undesired stresses. This can be activated in the contact table.

Frequently Asked Questions Below are a few frequency asked questions of Patran Advanced FEA users switching to the Marc Preference. 1. I have heard about a new Marc-based MSC.AFEA product. Exactly what is this MSC.AFEA product and what does the name stand for? The MSC.AFEA product is an interlocked version of Patran and Marc that will have a reduced price, but will restrict access to Marc features that are not supported by the Patran and the Marc Preference. It also requires that Patran and Marc be run on the same machine. Inter-locked means that the user will NOT be able to hand-edit the input deck and submit it directly to Marc, or to submit the job to a Marc installation on another computer.

Main Index

520 Marc Preference Guide Overview

The name MSC.AFEA is derived from the combination of MSC and AFEA. The MSC part comes from the company title, MSC Software, and the AFEA part was selected due to name recognition of the discontinued Patran integrated non-linear analysis product sold by MSC software called Patran Advanced FEA. 2. Does MSC.AFEA or the Marc Preference have all the capabilities of Patran Advanced FEA? It has everything and a lot more. The only item that is not supported to the same extent is in the area of random vibration analysis, although it is possible to do this in Marc with user subroutines. In addition to having all of the capabilities it also has much more as listed in Capabilities and Features. The combination of Patran and Marc (MSC.AFEA) is one of the most powerful, and easy to use, software combination available for nonlinear FEA available anywhere. Just about anything you could do in Patran Advanced FEA can be done just as easily in MSC.AFEA. Will my old Patran Advanced FEA models run directly in Marc? See the above Reference Section titled Database Conversion. As much data as is possible is converted. Even after using the new mapping capabilities, models containing more advanced features such as nonlinear material models, gap and beam elements, multi-stepping, mpc's and more complex capabilities that vary from one solver to the next in their implementation will likely require those features to be recreated (or at least checked) after the database Preference has been changed. 3. My company is not planning to upgrade Patran 2003 for a while. Can I still use Patran to build my Marc models? You should convert as soon a possible. The Marc Preference in Patran 9.0 and earlier had not kept up with changes in the latest releases of the Marc solver. In addition, there were several code defects, documentation errors and other deficiencies that made it difficult to build and completely run Marc models from earlier versions of Patran. There are also compatibility issues when you switch to Patran 2001 from version 9.5 and earlier in that the session and journal files Patran builds and uses as backup are not compatible, although the Marc Preference databases should successfully convert. The major capability missing in the Marc Preference of earlier version before 2001 is multistepping. In versions 2000 r2 and earlier you could do multi-stepping by using restarts, which was fully supported. The only thing to remember about multi-stepping in Marc using restarts is that the loads default to incremental loads and not total values. If you want to move the end of a cantilever beam down 1 unit in step 1, and then over 1 unit in step 2 you would have to apply a displacement of -1.0 in the vertical direction in step 1, and in step 2, apply a vertical displacement of 0.0 and a horizontal displacement of one.

Main Index

jp`Kc~íáÖìÉ=nìáÅâ=pí~êí=dìáÇÉ

Index Marc Preferance Guide

fåÇ Éñ Index

Numerics

D

3rd Order Invariant, 86

damage, 77, 102 damping, 76, 92 deactivate elements, 301 degrees-of-freedom, 36 delete, 21 demos, 25 direct results access, 340, 362 direct results access (DRA), 5 direct text input, 200, 331 domain decomposition, 335

A abort, 24, 25 activate elements, 301 adaptive load stepping, 270, 272, 277, 279 adaptive meshing, 206, 363 analysis, 19 form, 182 job parameters, 184 analysis execution, 4 analysis preference, 16 analyze, 19 Arruda-Boyce, 87 axisymmetric to 3D, 303

B body variables, 361 boundary conditions, 44

C components, 3 constitutive models, 110 contact, 18, 44, 64 deformable, 65 rigid, 68 contact detection, 194 contact parameters, 192 contact penetration, 194 contact table, 292 convergence problems, 342 coordinate frames, 31, 32 coordinates, 17 coupled analysis, 155 cracking, 77, 104 creep, 76, 92 cyclic symmetry, 42, 229

Main Index

E electrodynamic, 108 electrostatic, 108

522 Marc Preferance Guide

element properties, 119, 134 1D rebar membrane (165-170), 146, 150 2d solid, 123, 124 assumed plane strain solid (11), 150 assumed plane stress solid (3), 150 assumed solid (7), 153 assumed solid with auto tie (7), 153 axisym shell, 121, 122 axisym solid with twist (10,67), 150 axisym solid with twist (66,83), 150 axisymmetric shell (1,89), 145 axisymmetric solid (2,10,28,126), 150 axisymmetric solid (38,40,42,132), 150 beam (5,45), 135 beam with arbitrary section (31), 135 beam with general section (31), 135 beam with parabolic strain (45), 135 cable, 122 Cable (12), 144 closed section beam (14), 135 closed section beam (25), 135 closed section beam (76,78), 135 conduction link (36,65), 145 constant assumed with auto tie (7), 153 constant axisymmetric solid (10), 150 constant axisymmetric solid (20), 150 constant plane strain (11), 150 constant solid (7), 153 constant solid with auto tie (7), 153 constant/assumed plane strain (11), 150 constant/assumed solid (7), 153 convect/radiation link (36), 145 curve beam with arbitrary section (31), 135 curved beam with general section (31), 135 curved pipe (31), 135 damper, 122, 141 elastic beam, 121 Euler beam with arbitrary section (98), 135 Euler beam with general section (52), 135 Euler beam with general section (98), 135 fixed directional gap (12), 143 form, 119 gap, 122 general beam, 121 generalized plane strain (19,29), 150 generalized/constant plane strain (19), 150

Main Index

generalized/reduced plane strain (56), 150 hybrid axisym solid (33,82,129), 150 hybrid plane strain (32,80,128), 150 hybrid solid (35,84,130), 153 hybrid/reduced axisym solid (59,119), 150 hybrid/reduced plane strain (58,118), 150 hybrid/reduced solid (61,120), 153 laminated axisym shell (1,89), 145 laminated beam (5,45), 135 laminated composite, 124 laminated plate (49), 149 laminated thick shell (22,75), 149 laminated thin shell (72), 149 laminated with linear temp (85,86), 149 laminated with linear temp (87,88), 145 laminated with parabolic strain (45), 135 laminated/quadratic temp (85,86), 149 laminated/quadratic temp (87,88), 145 link, 122 mass, 121, 135 membrane (18,30), 149 open section beam (77.79), 135 pipe (14), 135 pipe (25), 135 pipe (31), 135 pipe (76,78), 135 planar beam, 121 planar solid (37,39,41,131), 150 plane strain solid (6,11,27,125), 150 plane stress solid (3,26,124), 150 plate (49), 149 rebar, 122 reduced axisymmetric solid (55,116), 150 reduced axisymmetric solid (70,122), 150 reduced planar solid (69,121), 150 reduced plane strain (54,115), 150 reduced plane strain solid (53,114), 150 reduced solid (57,117), 153 reduced solid (71,123), 153 reduced solid with auto tie (57), 153 shear panel (68), 149 shell, 124 shell with linear temp (85,86), 149 shell with linear temp (87,88), 145 shell with parabolic strain (22,75), 149 shell with quadratic temp (85,86), 149

INDEX

shell with quadratic temp (87,88), 145 solid, 124 solid (43,44,133,135), 153 solid (7,31,127,134), 153 solid with auto tie (7,21), 153 spring, 122, 141 spring/damper, 121, 135 thick shell, 122 thick shell (22,75), 149 thin shell, 122 thin shell (72), 149 thin-walled beam, 121 true distance gap (12), 143 truss, 122 elements, 32 energy calculations, 360 examples, 25, 365 executables, 3 exercises, 365 a simple contact problem, 411 a simple static load, 378 buckling of a fixed binned beam, 388 build a cantilever beam, 370 contact with velocity control, 430 creep analysis, 436 cummulative loading, 398 frequency response analysis, 472 heat transfer analysis, 481 natural frequency analysis, 445 nonlinear material plasticity, 420 transient dynamic analysis, 454

F failure, 75, 84 failure criteria, 85 FEA results, 396 fields, 18, 166

files, 6 control file, 5 error file, 6 job file, 4 message file, 4, 5 MSC.Marc input file, 6, 20 p3_trans.ini, 10 PCL libraries, 3 reject file, 6 results, 20 results files, 5 site setup, 10, 17 submit scripts, 3, 10 template database, 9 finite elements, 17 fixed load stepping, 280 foam, 87 forming limit, 77, 104 forward translation, 4 friction, 199 Full 3rd Order Invariant, 86

G Gent, 88 geometry, 17 global adaptive meshing, 213 global to local analysis, 303 global variable buckling mode, 360 critical load factor, 360 dynamic mode, 360 frequency (radians/time), 360 increment, 360 time, 360 grain size, 77, 105 groups, 202

H history definition cards, 508 hyperelastic, 75, 85

Main Index

523

524 Marc Preferance Guide

hyperelastic models Arruda-Boyce, 87, 88 Foam, 87 Gent, 88 Jamus-Green-Simpson, 86, 89 Mooney-Rivlin, 86, 89 Neo-Hookean, 86, 89 Ogden, 86 hypo-elastic, 76, 88

I input file translation, 6 iteration parameters, 288

J James-Green-Simpson, 86 job parameters, 184

Main Index

K keywords ACC CHANGE, 49, 508 ACTIVATE, 508 ADAPT GLOBAL, 206 ADAPTIVE, 206, 500, 502 ANISOTROPIC, 100 ANISOTROPIC (Mechanical), 83, 109, 502 ANISOTROPIC (Thermal), 94, 502 APPROACH, 254, 508 ARRUDABOYCE, 87, 502 ASSUMED, 186, 500 ATTACH EDGE, 502 ATTACH EDGES, 187 ATTACH ELEMENT, 502 ATTACH ELEMENTS, 187 ATTACH FACE, 502 ATTACH FACES, 187 ATTACH NODE, 206, 502 ATTACH NODES, 187 AUTO CREEP, 252, 269, 279, 280 AUTO INCREMENT, 269, 271, 290, 508 AUTO LOAD, 252, 269, 280, 508 AUTO STEP, 252, 261, 271, 273, 290, 508 AUTO THERM, 269, 277, 508 AUTO THERM CREEP, 269, 277 AUTO TIME, 508 AXITO3D, 157, 306, 502, 504, 505 BEAM SECT, 135, 500 BUCKLE, 272, 283, 317, 500, 508 BUCKLE INCREMENT, 283, 502 CENTROID, 186, 500 CHANGE STATE, 53, 305, 502, 508 COMPOSITE, 109, 502 CONNECTIVITY, 204, 319, 502 CONSTANT, 186, 500 CONTACT, 64, 193, 194, 196, 224, 254, 502 CONTACT NODE, 502, 503 CONTACT TABLE, 64, 67, 293, 508 CONTINUE, 331, 508 CONTROL, 258, 261, 289, 502 CONTROL(thermal), 502 COORDINATES, 32, 319, 502 COORIDINATES, 204 COUPLE, 500

INDEX

CRACK DATA, 104 CREEP, 92, 171, 250, 252, 502 CREEP INCREMENT, 252, 269, 280 CURVES, 187, 502 CYCLIC SYMMETRY, 229, 503 CYLINDRICAL, 31, 32, 503 DAMAGE, 102 DAMPING, 92, 283, 503 DEACTIVATE, 508 DEFINE, 202, 503 DENSITY EFFECTS, 107 DISP CHANGE, 49, 508 DIST CHARGE, 503 DIST CHARGES, 63 DIST CURRENT, 64, 503 DIST FLUXES, 60, 503, 508 DIST LOAD, 52, 55, 309, 503, 508 DIST LOADS, 57, 58 DYNAMIC, 272, 274, 283, 317, 500 DYNAMIC CHANGE, 269, 280, 282 ELASTIC, 208, 237, 500 ELASTICITY, 208, 500 ELEVAR, 224 ELEVEC, 224 END, 201, 500 END OPTION, 201, 503 ERROR ESTIMATES, 319, 503 EXCLUDE, 68 EXTENDED, 187, 500 FAIL DATA, 84, 503 FILMS, 59, 503, 508 FINITE, 236, 500 FIXED ACCE, 49, 503 FIXED DISP, 49, 503 FIXED EL-POT, 63, 503 FIXED TEMPERATURE, 53, 503 FIXED VOLTAGE, 503 FLUX, 60 FOAM, 87, 88 FOLLOW FOR, 500 FOLLOW FORCE, 46, 237 FORCDT, 50, 52, 54, 61 FORCEM, 53 FORMING LIMIT, 104 GAP DATA, 143, 503

Main Index

GASKET, 123, 152, 503 GENT, 88, 504 GEOMETRY, 135, 144, 145, 146, 149, 150, 154, 504 GLOBALLOCAL, 308 GRAIN SIZE, 105 HARMONIC, 246, 508 HEAT, 257, 260 history definition, 508 HYPELA, 89 HYPELA2, 89 HYPOELASTIC, 88, 504 IMPD, 224 INITIAL DISP, 56, 504 INITIAL STATE, 80, 82, 83, 86, 89, 305, 504 INITIAL TEMP, 61, 504 INITIAL VEL, 56, 504 INITSV/NEWSV, 54 INSERT, 146, 150, 504 inverse power sweep, 240 ISOTROPIC, 95 ISOTROPIC (Electrostatic), 504 ISOTROPIC (Heat Transfer), 93, 504 ISOTROPIC (heat transfer), 93 ISOTROPIC (Stress), 80, 504 ISOTROPIC,ELECTROSTA, 108 ISOTROPIC,THERMAL, 108 Lanczos, 241 LARGE DISP, 236, 247, 249, 500 LINEAR, 500 LOADCASE, 49, 50, 51, 52, 55, 314, 504, 508 LUMP, 186, 500 MASSES, 135, 504 MATERIAL DATA, 105 MODAL INCREMENT, 283, 504 MODAL SHAPE, 240, 508 model definition, 502 MOONEY, 86, 504 MOTION CHANGE, 64, 254, 508 MPC-CHECK, 190 NO LOADCOR, 500 NODAL THICKNESS, 135, 146, 149, 504 OGDEN, 86, 88, 504

525

526 Marc Preferance Guide

OPTIMIZE, 190, 504 ORIENTATION, 149, 150, 153, 154, 504 ORTHO TEMP, 100, 170, 176, 505 ORTHOTROPIC (mechanical), 82, 100, 505 ORTHOTROPIC (Thermal), 93, 505 ORTHOTROPIC,ELECTROSTA, 108 ORTHOTROPIC,THERMAL, 108 parameters, 500 PHI-COEFFICIENTS, 86, 505 PHI-COEFICIENTS, 171 PLASTICITY, 208 PLOTV, 224 POINT CHARGE, 63, 505 POINT CURRENT, 64 POINT FLUX, 61, 505, 508 POINT LOAD, 51, 58, 505, 508 POINT TEMP, 53, 505 POINTS, 187, 505 POST, 186, 205, 274, 316, 320, 505 POST INCREMENT, 316, 509 POWDER, 107 PRE STATE, 306 PRING NODE, 505 PRINT ELEMENT, 317, 505, 509 PRINT NODE, 317, 509 PROPORTIONAL INCREMENT, 283, 505, 509 RADIATION, 227, 500 REAUTO, 205, 505 REBAR, 146, 150, 505 RECOVER, 241, 316, 509 RELATIVE DENSITY, 107 RELEASE, 295, 509 RELEASE NODE, 50, 509 RESPONSE, 250 RESPONSE SPECTRUM, 250, 505 RESTART, 204, 505 RESTART LAST, 204, 271, 505 REZONING, 206, 500, 501 ROTATION A, 55, 505 SCALE, 252, 272, 282, 501, 505 SERVO LINK, 37, 43, 506 SETNAME, 202, 501 SHAPE MEMORY, 101 SHELL SECT, 324, 501 SHIFT FUNCTION, 90

Main Index

SIZING, 191 SOIL, 106 SOLVER, 190, 289, 506, 509 SPECTRUM, 249, 509 SPFLOW, 309, 501 SPLINE, 65, 506 SPRING, 122 SPRINGS, 141, 506 STEADY STATE, 258, 509 STOP, 501 STRAIN RATE, 95, 100, 171, 173, 176, 506 SUMMARY, 319, 509 SUPERPLASTIC, 309, 509 superplastic forming, 53 SURFACE, 206 SURFACES, 187, 506 SYNCRONIZE, 254, 509 TABLE, 49, 50, 51, 52, 55, 152, 169, 180, 187, 254, 501, 506 TEMP CHANGE, 53, 509 TEMPERATURE EFFECTS, 81, 86, 87, 95, 170, 506 TIME STEP, 254, 258, 280, 509 TITLE, 501 TRANSFORMATION, 31, 32, 506 TRANSIENT, 261, 277, 509 TRANSIENT NON AUTO, 258, 261 TSHEAR, 501 TYING, 36, 506 UBEAM, 89 UCONTACT, 224, 506 UDUMP, 224, 225 UFRICTION, 224, 506 UHTCOE, 506 UHTCOEF, 224 UHTCON, 224, 506 UMOTION, 224, 507 UORIENT, 149, 151, 153, 507 UPDATE, 236, 501 UPSTNO, 224 USDATA, 225 UTRANSFORM, 225 VELOCITY, 62, 507 VELOCITY CHANGE, 509 VIEW FACTOR, 227, 507 VIEWFACTOR, 62

INDEX

VISCEL EXP, 507 VISCELMOON, 89, 171, 507 VISCELOGDEN, 89, 171, 507 VISCELORTH, 89, 507 VISCELPROP, 89, 171, 507 VISCO ELAS, 224 WORK HARD, 95, 100, 170, 176, 224, 507

L linear beam theory, 385 load and boundary conditions 1D Pressure, 45, 57 acceleration, 45, 49 charge, 46, 63 CID distributed load, 45, 58 contact, 45 convection, 45, 59 convective velocity, 45, 62 current, 46, 64 displacement, 45, 49 force, 45, 51 heat flux, 45, 60 heat source, 45, 61 inertial load, 45, 55 initial displacement, 45, 56 initial temperature, 45, 61 initial velocity, 45, 56 potential, 46, 63 pressure, 45, 52 radiation, 45, 61 release, 50 static, 46 temp (thermal), 53 temperature, 45, 53 time dependent, 47 voltage, 46, 63 load cases, 18, 164, 313 load incrementation parameters, 267 load steps, 164 creating, 232 selecting, 333 loading criteria, 275 loads, 44 loads and boundary conditions, 18, 44 local adaptive meshing, 210

Main Index

M marcp3, 6 MarcSubmit, 10 marpat3, 5 material library, 74 material properties, 79 materials, 18 2d anisotropic, 80 elastic, 80 plastic, 100 2d anisotropic (thermal), 93 2d orthotropic plastic, 100 2d orthotropic (thermal), 93 3d anisotropic, 80 plastic, 100 3d anisotropic (thermal), 93 3d orthotropic plastic, 100 3d orthotropic (thermal), 93 composite, 108 cracking, 77, 104 creep, 76, 92 damage, 77, 102 damping, 76, 92 elastic, 75 electrodynamic, 108 electrodynamics, 78 electrostatic, 78, 108 failure, 75, 84 forming limit, 77, 104 grain size, 77, 105 hyperelastic, 75, 85 hypoelastic, 76, 88 isotropic, 75, 80 elastic, 80 plastic, 95 isotropic (thermal), 93 orthotropic, 80 plastic, 78 powder, 77, 107 shape memory, 76, 101 soil, 77, 106 thermal, 76 viscoelastic, 76, 89

527

528 Marc Preferance Guide

model definition cards, 502 model import, 6 monitor, 22 Mooney-Rivlin, 86 motion control, 180 MSC.AFEA product information, 2 MSC.Marc product information, 2 Patran product information, 2 multi-point constraints, 33 axi shell-solid, 38 cyclic symmetry, 39, 42 explicit, 37 full moment joint, 39 linear surf-surf, 37 linear surf-vol (temperature), 37 linear vol-vol, 37 overclosure, 41 pinned joint, 39 quad plate-plate, 39 quad surf-surf, 38 quad surf-vol (temperature), 38 quad vol-vol, 38 RBE2, 40 RBE3, 41 rigid (fixed), 37 rigid link, 39 sliding surface, 39, 43 tie dofs, 38 tri plate-plate, 38

N Neo-Hookean, 86 nodes, 32

O Ogden, 86 optimization optimize, 190

Main Index

output requests form, 314 linear buckling, 314 linear model extraction, 314 linear static, 315 linear steady state heat, 314 linear transient dynamic, 314 linear transient heat, 314 modal superposition, 314 nonlinear buckling, 314 nonlinear modal extraction, 314 nonlinear static, 315 nonlinear steady state heat, 314 nonlinear transient dynamic, 314 nonlinear transient heat, 314

P parallel processing, 335 parameter cards, 500 pat3mar, 4 pcl library, 4 penetration, 194 plastic, 78 plots, 19 powder, 77, 107 Preference componenets, 3 preferences, 16 programs, 3 properties, 18 elements, 134 materials, 79

R radiation, 61, 226 read input file, 20 read results, 20 rebar, 226 rebar definition tool, 157 reference temperature, 81 remeshing, 206 remote hosts, 10 remote submittal, 12 restart file, 205 parameters, 204

INDEX

result types acceleration, 354 rotation, 354 translation, 354 displacement, 354 rotation, 354 translation, 354 energy density, 358 elastic, 358 plastic, 358 total, 358 failure, 358 index no.1, 358 index no.2, 358 index no.3, 358 index no.4, 358 index no.5, 358 index no.6, 358 index no.7, 358 flux, 355, 358 element, 358 nodal, 355 force, 354 nodal external applied, 354 nodal reaction, 354 modal mass, 354 rotation, 354 translation, 354 moment, 354 nodal external applied, 354 nodal reaction, 354 state variable, 358 second, 358 third, 358 strain, 356, 357 cracking, 356 creep, 356 creep equivalent, 356 creep equivalent (rom rate), 356 elastic, 356 elastic equivalent, 356 plastic, 357 plastic equivalent, 357 plastic equivalent (from rate), 357 plastic equivalent rate, 357

Main Index

thermal, 357 thickness, 357 total, 357 stress, 357 Cauchy, 357 Cauchy equivalent Mises, 357 equivalent Mises, 357 hydrostatic, 357 interlaminar shear no.1, 357 interlaminar shear no.2, 357 temperature, 354, 357 element, 357 element gradient, 357 element incremental, 357 nodal, 354 thickness, 358 velocity, 354 rotation, 354 translation, 354 volume, 358 results, 19 both import, 350 created, 353 delete, 349 elemental, 323 model import, 350 nodal, 320 print, 317 select file, 349 translation parameters, 350 results translation, 5 ResultsSubmit, 5 reverse translation, 5 rigid bodies, 180 rigid body animation, 362 rigid body motion, 73

S scale factors, 165 separation, 196 shape memory, 76, 101 site setup, 10 sliding surface, 43 soil, 77, 78, 106

529

530 Marc Preferance Guide

solution type, 233, 234 body approach, 253 creep, 250 frequency response, 246 linear buckling, 241 linear harmonic response, 246 linear modal extraction, 239 linear static, 235, 255 linear steady state heat, 257 linear transient dynamic, 243 linear transient heat, 260 modal superposition, 244 nonlinear buckling, 241 nonlinear modal extraction, 239 nonlinear static, 235 nonlinear steady state heat, 257 nonlinear transient dynamic, 243 nonlinear transient heat, 260 single increment, 255 spectrum response, 248 solver options, 190 structural zooming, 303 superplastic forming, 309 supported keywords, 500

T tables, 18, 166 material properties, 167, 169 non-spatial properties, 178 spatial properties, 178 spatial variations, 168 time/frequency variations, 168 temperature loading, 303 template database, 9 text input, 200, 331 thermal, 76 thermal radiation, 226 translation, 3 forward, 4 input file, 6 reverse, 5 translation parameters, 184

Main Index

tutorial guide, 366 application form selection, 368 menu bar selection, 368 menu notations, 369 user input, 368

U uasge scenarios, 283 usage scenarios, 258, 262 user compiled program, 220 User Sub. UELASTOMER, 88 user subroutine ANELAS, 83 ANEXP, 83, 89 ANKOND, 81, 93 CRPLAW, 92 HYPELA, 89, 106 HYPELA2, 89 ORIENT, 81, 93 TRSFAC, 90 UBEAM, 89 UCRACK, 104 UDAMAG, 103 UFAIL, 85 UGRAIN, 105 UPOWDR, 107 UVSCPL, 95 user subroutine file, 220

V viewfactors, 226 viscoelastic, 76, 89 viscoplastic, 95