Rr210102 Strength Of Materials I

Set No. 1

Code No: RR210102

II B.Tech I Semester Regular Examinations, November 2007 STRENGTH OF MATERIALS-I (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. A steel bolt of 650 sq.mm C.S.A passes centrally through a copper tube of C.S.A. 1200 sq. mm. the tube is 500 mm long and is closed by rigid washers which are fastened by the threads on the steel bolt. The pitch of the thread is 3 mm. If the nut is tightened through 900 , find the stresses in the bolt and the tube. [16] 2. (a) What do you understand by “ resilience” ? (b) A steel bar of 20 mm dia. is pulled axially by a force of 18 k N. If the bar is 300 mm long, calculate the strain-energy stored per unit volume and the total strain energy stored by the bar. Take E = 200 GPa. [4+12] 3. Draw the B. M. D and S. F. D for the beam shown in Figure 3

[16]

Figure 3 4. Design the cross section for a beam acted upon by a bending moment = 50 KNm. If width of beam is 200 mm calculate, depth. f = 9 N/mm2 . [16] 5. Find the forces in all the members of the warrentype Cantilever truss shown in Figure 5 by the method of sections. Tabulate the values. [16]

Figure 5 6. (a) Explain Macaulay’s method. (b) Derive the expression for the slope and deflection of a cantilever beam of length L, carrying a point load W at the free end by double integration method. [8+8] 7. (a) Define the efficiency of a riveted joint. 1 of 2

Set No. 1

Code No: RR210102

(b) A single riveted lap joint is used to connect plates of 12mm thick, if 20mm diameter rivets are used at 55mm pitch, determine the strength of joint and its efficiency. [8+8] 8. Define the terms (a) Circumferential stress (b) Longitudinal stress and derive the expressions for the same in thin cylinders. [16] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR210102

II B.Tech I Semester Regular Examinations, November 2007 STRENGTH OF MATERIALS-I (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. State Hooke’s law. Sketch the stress- strain diagram for a ductile material like mild steel tested under tension upto destruction, marking the salient points on it. Explain the significance of each point. [16] 2. A bar 1 m long is subjected to an axial pull which produces a max. stress of 1.5 N/mm2 . For the middle 10 cm length the sectional area is 100 mm2 and for both the end portions of lengths 45 cm the area is 200 mm2 . Calculate the strain energy stored in the bar, if E = 200 Gpa. [16] 3. (a) Define the “Beam” and the type of action and deformation it undergoes. (b) Draw the S.F. and B.M. diagram for a simply supported beam of span L m loaded with UDL of w KN/m. [6+10] 4. For a channel section shown in Figure 4 determine the section modulus. Hence calculate the maximum bending stresses. Sketch the distribution of bending stress if the section is subjected to a B. M = 40 KNm. [16]

Figure 4 5. Determine the forces in all the members of the truss and their nature for the simply supported truss shown in Figure 5. [16]

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Set No. 2

Code No: RR210102

Figure 5 6. Determine the deflection of the beam at the point of application of the 300 N.m couple as shown in Figure 6. Use E=2x105 N/sq.mm and I=200 cm4 . [16]

Figure 6 7. Design a riveted Joint as a (a) Single cover butt Joint (b) Double cover butt Joint to connect two plates 20mm thick. Power driven rivets may be used for making the connection. Find the efficiency of the Joint in both the cases. Which is preferred. [16] 8. Define the terms (a) Circumferential stress (b) Longitudinal stress and derive the expressions for the same in thin cylinders. [16] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: RR210102

II B.Tech I Semester Regular Examinations, November 2007 STRENGTH OF MATERIALS-I (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Explain the Following: (a) Elasticity and Plasticity (b) Ductility and Malleability (c) Stress and Strain (d) Limit of proportionality and Elastic Limit

[4+4+4+4]

2. A uniform metal bar of 1.5 m length, area of section 600 mm2 has an elastic limit of 160 N / mm2 . Find its proof resilience, if E = 200 Gpa . Find also the max. applied load which can be suddenly applied without exceeding the elastic limit. Calculate the magnitude of the gradually applied load which will produce the same extension. [16] 3. Construct the S. F. D & B. M. D for the simply supported beam shown in Figure 3 [16]

Figure 3 4. Define Neutral axis. Sketch the bending stress distribution across the cross section of a rectangular beam section 230 × 400 m subjected to 60 KNm moment. [16] 5. (a) Define and explain the terms : The perfect frame, imperfect frame, deficient frame and a redundant frame. (b) Analyse the truss shown in Figure 5 by the method of sections.

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[4+12]

Set No. 3

Code No: RR210102

Figure 5 6. (a) Explain the Mohr’s theorems, for finding the slope and deflection of a beam. (b) A simply supported 6m rolled steel joist carries a U.D.L of 10 KN//m length. Determine slope and deflection at a distance of 3m from one end of the beam. [6+10] 7. A bridge truss diagonal carries an axial pull of 500kN. It is to be connected to a gusset plate 22mm thick by a double cover butt Joint with 22mm rivets. If the width of the flat tie bar is 250 mm, determine the thickness of flat. Design an economical Joint. Determine the efficiency of Joint. Sketch the Joint. Use power driven rivets and adopt permissible stresses as per I.S. 800. [16] 8. A cylindrical thin drum 800mm in diameter and 3m. long has a shell thickness of 10mm. If the drum is subjected to an internal pressure of 2.5 N/mm2 , determine (a) Hoop stress (b) Longitudinal stress (c) Change in diameter (d) Change in length (e) change in volume. Take E = 2 X 105 N/mm2 , µ = 0.25. ⋆⋆⋆⋆⋆

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[16]

Set No. 4

Code No: RR210102

II B.Tech I Semester Regular Examinations, November 2007 STRENGTH OF MATERIALS-I (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Find the Poisson’s ratio and Bulk modulus of a material whose modulus of elasticity is 200 GPa and modulus of rigidity is 80 GPa. A 2 m long rod of 40 mm dia. made with the same material is stretched by 2.5 mm under some axial load. Find the lateral contraction. [16] 2. A weight of 210 kN is supported by three short pillars each of sectional area 500 mm2 . The central pillar is of steel and the outer ones are of copper. The pillars are so adjusted that at a temperature of 150 C each carries equal load. The temperature is then raised to 950C. Find the stress in each pillar at 150 C and 950 C. Take Es = 200 GPa and EC = 80 GPa αs = 12 × 10−6 / 0 C and αc = 18 × 10−6 / 0 C. [16] 3. Construct the S. F. D. and B. M. D. for the cantilever beam shown in Figure 3 and identify the maximum values for each. [16]

Figure 3 4. Define Neutral axis. Sketch the bending stress distribution across the cross section of a rectangular beam section 230 × 400 m subjected to 60 KNm moment. [16] 5. A pin jointed frame is as shown in Figure 5. It is hinged at A and loaded at D. A horizontal chain is attached to C and pulled so that AD is horizontal. Determine the pull in the chain and also the force in each member stating whether it is in tension or compression . [16]

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Set No. 4

Code No: RR210102

Figure 5 6. Determine the deflection of the beam at the point of application of the 300 N.m couple as shown in Figure 6. Use E=2x105 N/sq.mm and I=200 cm4 . [16]

Figure 6 7. (a) Define the following terms: i. Gauge distance ii. Staggered pitch iii. Rivet line. (b) Design a double cover butt Joint to connect two plates each 12mm thick. The load to be transferred by the Joint is 400 kN. [6 +10] 8. (a) Define the terms i. Hoop stress ii. Maximum shear stress (b) Calculate the increase in volume enclosed by a boiler shell 2.4 m long, and 1m. in diameter, when it is subjected to an internal pressure of 2 N/mm2 . The wall thickness is such that, the maximum tensile stress in the shell is 25 N/mm2 under this pressure. Take E = 2 X 105 N/mm2 , µ = 0.25. [4+12] ⋆⋆⋆⋆⋆

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