JNTUH
JNTUH B.Tech II MECHANICS OF SOLIDS Previous Question Paper (May - 2019 - R15)
Note: This question paper contains two parts A and B. 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.
Part A
Distinguish between elasticity and plasticity.
Answer
Elasticity is the property of a material by virtue of which it regains its original shape and size after the removal of an external load. Plasticity is the property by which a material undergoes permanent deformation and retains its changed shape even after the removal of the load.
What is factor of safety? State its importance.
Answer
Factor of safety is the ratio of the ultimate stress of a material to its working or permissible stress. It is essential to ensure structural safety by accounting for uncertainties in loading, material properties, and manufacturing defects, preventing failure under unexpected overloads.
Define shear force diagram.
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Differentiate between a cantilever and a simply supported beam.
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Compute the section modulus of a circular section of diameter 200mm.
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Draw the shear stress distribution diagram for a rectangular section.
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State maximum principal stress theory.
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The principal stresses at a point are 100N/mm2 (tensile) and 50N/mm2 (compressive) respectively. Compute the maximum shear stress at this point.
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What is the power transmitted by circular shaft subjected to a torque of 700kN-m at 110rpm?
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What is meant by Hoop stress and longitudinal stress?
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Part B
A straight bar 450mm long is 20mm for the 250mm length and 10mm diameter for the remaining length. If the bar is subjected to an axial pull of 10,000N, compute the stresses and extension of the bar. Take E=2×105N/mm2.
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Draw the stress – strain curve for tension test on a ductile material and mark the significant points on it.
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A rectangular block 200mm × 150mm × 50mm is subjected to axial load as follows: (a) 300kN compressive in the direction of its length, (b) 500kN tensile in the direction of its breadth and (c) 200kN tensile in the direction of its thickness. Evaluate the change in volume, assuming E=2×105N/mm2 and Poisson’s ratio=0.3.
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Draw the shear force and bending moment diagrams for a cantilever of length ‘L’ carrying a uniformly distributed load of ‘w’ per meter length over its entire length.
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A cantilever beam of length 2m carrying a point load 3kN at the free end. Draw the shear force and bending moment diagrams for the cantilever.
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Draw the shear force and bending moment diagrams for the simply supported beam as shown in figure.
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Derive the bending equation
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Prove that the maximum shear stress in a rectangular section of a beam is 1.5 times the average shear stress.
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The principal stresses at a point in a bar are 200N/mm2 (tensile) and 100N/mm2 (compressive). Determine the resultant stress in magnitude and direction on a plane inclined at 60o to the axis of the major principal stress.
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Write short note on maximum shear stress theory.
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The stresses induced at a critical point in a machine component made of steel 45C8 (σy = 380 N/mm2) are as follows: σx = 100 N/mm2; σy = 40 N/mm2; τxy = 80 N/mm2. Calculate the factor of safety by maximum shear stress theory.
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A solid shaft of 150mm diameter is used to transmit torque. Compute the maximum torque transmitted by the shaft if the maximum shear stress induced to the shaft is 45N/mm2.
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What is polar modulus? Find the expressions for polar modulus for a solid shaft.
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Derive an expression for circumferential stress for a thin cylinder subjected to an internal pressure.
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A cylinder of internal diameter 0.5m contains air at a pressure of 7N/mm2. If the maximum permissible stress induced in the material is 80N/mm2, estimate the thickness of the cylinder.
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