JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II STRENGTH OF MATERIALS II Previous Question Paper (March - 2022 - R13)
Answer any five questions. All questions carry equal marks.
Main
Determine the diameter of a solid shaft which will transmit 300 kW at 250 rpm. The maximum shear stress should not exceed 30 N/mm2 and twist should not be more than 1o in a shaft length 2 m. Take modulus of rigidity G= 1 × 105 N/mm2.
Answer
Given: Power P = 300 kW = 300,000 W, Speed N = 250 rpm, Maximum shear stress τ = 30 N/mm2, Angle of twist θ = 1° = (π/180) radians, Length L = 2 m = 2000 mm, Modulus of rigidity G = 1 × 105 N/mm2.
First, calculate the torque T transmitted by the shaft:
1. Based on strength (shear stress):
Substituting the values:
2. Based on stiffness (angle of twist):
Substituting the values:
To satisfy both conditions, we select the larger diameter: d = 124.83 mm.
List the assumptions made in the derivation of Torsion equation.
Answer
- The material of the shaft is uniform, isotropic, and homogeneous.
- The shaft is circular in cross-section and remains circular after twisting.
- Plane sections of the shaft remain plane after the torque is applied.
- The twist is uniform along the length of the shaft.
- The stress induced is within the elastic limit, and Hooke's Law applies.
A closely coiled helical spring of round steel wire 10 mm in diameter having 10 complete turns with a mean diameter of 120 mm is subjected to an axial load of 250 N. Determine the deflection of the spring, maximum shear stress in the wire and stiffness of the spring. Take G = 0.8 × 105 N/mm2.
Answer
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Derive the expression for maximum shear stress in the wire in close coiled helical spring.
Answer
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A slender column fixed at one end and free at the other end is subjected to an eccentric load. Find the expression for the maximum length 'L' of the column such that the deflection at the free end does not exceed the eccentricity 'e' of the loading.
Answer
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Classify columns according to the nature of failure.
Answer
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A circular beam of radius 5 m and uniform cross-section is supported on six symmetrically placed columns. The beam is subjected to a uniformly distributed load of intensity 20 kN/m. Determine the position and magnitude of maximum torsional moment.
Answer
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A masonry dam of rectangular section, 20 m high and 10 m wide, has water up to a height of 16 m on its one side. Find:
a) Pressure force due to water at 10 m height of dam
b) Position of center of pressure and the point at which the resultant cuts the base. Take weight density of masonry = 19.62 kN/m3 and of water = 9.81 kN/m3. Calculate the maximum and minimum stress intensities at base of dam.
Answer
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Derive the equation for maximum bending moment of a strut subjected to Compressive axial load and a transverse point load at Centre if both ends are pinned.
Answer
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Find the safe uniform load carried by the I section which is simply supported for the given data. Also find the maximum compressive stress. Top flange: 80 mm × 20 mm, Web: 20 mm × 200 mm, Bottom flange: 160 mm × 40 mm. Tensile stress not to exceed: 20 N/mm2. Span of beam: 5 m
Answer
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List the assumptions made in Unsymmetrical bending of beams.
Answer
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A cylindrical pipe of diameter 1.5 m and thickness 15 mm is subjected to an internal fluid pressure of 1.8 N/mm2. Determine the longitudinal stress and hoop stress developed in the pipe.
Answer
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Explain the stresses to be developed in a thin cylindrical shell.
Answer
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