B.Tech II Year I Semester Examinations, December - 2018

STRENGTH OF MATERIALS-I

(Civil Engineering)

Time: 3 hours Max. Marks: 75

Note: This question paper contains two parts A and B.

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Part A is compulsory which carries 25 marks. Answer all questions in Part A.

Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks.

PART- A (25 Marks)

1. a) Define Resilience. [2M]

2. b) Define Bulk Modulus. [3M]

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3. c) Define Shear Force. [2M]

4. d) Define Point of Contraflexure. [3M]

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5. e) State the assumptions made in the theory of simple bending. [2M]

6. f) Define Section Modulus. [3M]

7. g) Define Torsion. [2M]

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8. h) Define Polar Modulus. [3M]

9. i) Define Principal Stresses. [2M]

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10. j) What are the various theories of failure? [3M]

PART-B (50 Marks)

UNIT-I

2. A steel rod of 3 cm diameter and 5 m long is connected to two grips and the rod is maintained at a temperature of 95°C. Determine the stress and pull exerted on the grips when the temperature falls to 30°C if i) The ends do not yield and ii) The ends yield by 0.12 cm. Take E = 2 × 10⁵ MN/m² and a = 12 × 10^-6/°C. [10M]

3. Determine the stresses in various segments of the circular bar shown in below figure. What is the net change in the length of the bar? Take E = 200 GPa.

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   [10M]

UNIT-II

4. A simply supported beam of length 5m carries a uniformly distributed load of 10kN/m over a length of 2m from the right end. Draw the S.F and B.M diagrams for the beam and also calculate the maximum B.M value. [10M]

5. A cantilever beam 2 m long carries a uniformly distributed load of 2 kN/m over a length of 1 m from the free end, and a point load of 1 kN at the free end. Draw the shear force and bending moment diagrams. [10M]

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UNIT-III

6. A timber beam 100 mm wide and 150 mm deep supports a UDL over a span of 2m. If the safe stresses are 28 N/mm² in bending and 2 N/mm² in shear, calculate the maximum load which the beam can carry. [10M]

7. A rolled steel joist 350 mm × 200 mm has flange thickness of 14.2 mm and web thickness of 8.5 mm. Determine the safe uniformly distributed load per metre length, which the beam of 6 m span can carry if the flange stress is limited to 150 N/mm². [10M]

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UNIT-IV

8. A solid shaft transmits 100 kW at 75 r.p.m. Determine the diameter of the shaft if the shear stress is not to exceed 50 MPa and the angle of twist in a length of 2 m should not exceed 1°. Take C = 80 GPa. [10M]

9. Determine the diameter of a solid shaft which will transmit 440 kW at 280 r.p.m. The angle of twist must not exceed 1 degree per metre length and the maximum torsional shear stress is to be limited to 40 N/mm². Assume G = 80 kN/mm². [10M]

UNIT-V

10. At a point in a strained material, the principal stresses are 100 N/mm² (Tensile) and 60 N/mm² (Compressive). Determine the normal stress, shear stress and the resultant stress on an oblique plane inclined at 45° with the major principal plane. [10M]

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11. A point in a strained material is subjected to a tensile stress of 50 N/mm² and a shear stress of 25 N/mm². Determine the normal and shear stresses on a plane inclined at 30° with the tensile stress. [10M]

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