Materials

Iron is taken from the earth and copper is smelted from ore. Man puts an end to the darkness; he searches the farthest recesses for ore in the darkness. The Bible (Job 28:2-3)

Image: Iron flows from a blast furnace. Source: American Iron and Steel Institute.

σε P

P

(σ ε

A

Figure 3.5 Stress-strain diagram for a ductile material. text reference: Figure 3.5, , page 96

σε

σε

text reference: Figure 3.6, page 97

æ l fr − l0 ö EL = çç × l è 0

%EL

Manifest danger stress concentrations Figure 3.1 Ductile material from a standard tensile test apparatus. (a) Necking; (b) failure. text reference: Figure 3.1, page 90

%EL %EL

Figure 3.2 Failure of a brittle material from a standard tesile test apparatus.

text reference: Figure 3.2, page 91

text reference: Figure 3.7, page 98

text reference: Figure 3.8, page 99

Figure 3.10 Stress-strain diagram for polymer below, at, and above its glass transition temperature Tg. text reference: Figure 3.10, page 101

E=

σ ε

Esteel Ealum

uniaxial

linear

τyx

γyx

θyx

G=

τ γ

torsion

x y

ν =− νsteel νalum νrubber

ε axial

ε transverse v

v G

E

G=

E +υ )

(

yield Allowable

building S y ≤ σ allow ≤

τ allow =

Sy

Sy

S y ≤ σ allow ≤

σ allow =

Sy

Sy

εy

U r = σ dε 0

rupture

Class Enginering alloys (the metals and alloys of engineering)

Members Aluminum alloys Copper alloys Lead alloys Magnesium alloys Molybdenum alloys Nickel alloys Steels Tin alloys Titanium alloys Tungsten alloys Zinc alloys Engineering polymers Epoxies (the thermoplastics and Melamines thermosets of engineering) Polycarbonate Polyester Polyethylene, high density Polyethylene, low density Polyformaldehyde Polymethylmethacrylate Polypropylene Polytetrafluoroethylene Polyvinyl chloride Engineering ceramics Alumina (fine ceramics capable of Diamond load-bearing application) Sialons Silicon carbide Silicon nitride Zirconia

Short name Al alloys Cu alloys Lead alloys Mg alloys Mo alloys Ni alloys Steels Tin alloys Ti alloys Walloys Zn alloys EP MEL PC PEST HDPE LDPE PF PMMA PP PTFE PVC Al2O3 C Sialons SiC Si3N4 ZrO2

text reference: Table 3.7, page 123

RA RB

SU

HB SU

HB

RC

HB HB

Table 3.7 Material classes and members and short names of each member. [From Ashby (1992)].

Charpy

Izod

quenching

critical temperature

below critical temperature and

carburizing

hardness strength

hardness

toughness

Expensive!

y

y

Brass

zinc

Figure 3.4 Cross section of fiber reinforced composite material. text reference: Figure 3.4, page 95

Figure 3.3 Strength/density for various materials. text reference: Figure 3.3, page 94