Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech II MECHANICS OF SOLIDS Previous Question Paper (November/December - 2017 - R13)
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. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Draw the stress-strain curve for mild steel and indicate salient points.
Answer
The stress-strain curve for mild steel plots stress on the y-axis and strain on the x-axis. Salient points include the limit of proportionality, elastic limit, upper yield point, lower yield point, ultimate stress point, and the fracture (breaking) point.
What is lateral strain and poisson’s ratio?
Answer
Lateral strain is the strain occurring in a direction perpendicular to the applied axial load. Poisson’s ratio is the ratio of lateral strain to longitudinal strain within the elastic limit.
Describe the concept of shear force in beams.
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Differentiate between varying loads and uniformly distributed loads.
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What assumptions are made in theory of simple bending?
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What are the advantages and applications of I-Section?
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What are the axial stresses and compound stresses?
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What is maximum principal stress theory?
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How the shaft is designed for maximum shear stress?
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What is hoop-stress and volumetric strain in shells?
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Part B
How the temperature stresses are developed?
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A steel bar is placed between two copper bars of same area and length at a temp of 15°C. At this stage, they are rigidly connected together at both ends. When the temperature is raised to 315°C, the length of bars increase by 1.6 mm. Find the original length and stresses in bars. Take Es = 200 Gpa, Ec = 100 Gpa, αs = 0.000012 per °C, αe = 0.000018 per °C.
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Derive equation for the relation between three elastic moduli.
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A bar of 25 mm diameter is subjected to a pull of 70 kN. The extension measured on a gauge length of 200 mm is 0.1 mm and change in diameter is 0.004 mm. Find poisson’s ratio and values of three moduli.
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A simply supported beam of span 10 m carry as UDL of 10 KN/m over a length of 3 m from left support and also from right support. Draw SF and BM diagram.
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A beam of length 12 m has overhanging of 3 m on left and right leaving the span between the supports of 6 m. It carries UDL of 8 KN/m over the entire length and a concentrated load of 10 KN at the right extreme end. Draw SF and BM diagrams and find the point of contraflexure point.
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How to find neutral axis of a beam and explain its importance?
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A cantilever beam of cross-section 90 mm width 120 mm deep carries a UDL of 12 KN/m over the entire length and a concentrated load of 15 KN at the right end. Find the bending stress in the beam, when the length of beam is 10 m.
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A rolled steel Joist of I-Section has flange length of 300 mm wide and 20 mm thick with a web thickness of 20 mm and overall depth of I-Section is 600 mm. If this beam carries a UDL of 40 KN/m over the simply supported beam of span 10 m, find the maximum stress produced in the beam.
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At a point in a strained material, the intensities of normal stresses on two planes at right angles to each other are 35 N/mm² and 20 N/mm² both tensile. They are accompanied by shear stress of 15 N/mm². Find the principal planes and principal stresses. Find also maximum shear stress.
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A circular shaft of 12 cm dia is subjected to combined bending and twisting moments. The bending moment being three times the twisting moment. If the direct tensile yield point of material is 350 MN/m² and factor of safety on yield is 4, find the allowable twisting moment by a) Maximum principal stress theory b) Maximum shear stress theory.
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A hollow shaft of 600 mm external dia and 400 mm internal dia is transmitting a power of 6000 KW at 160 rpm. Find the shear stresses at the outer and inner surfaces of the shaft. Draw the shear stress distribution for the wall of the shaft. Find the twist over a length of 4 m of the shaft. Take E = 80 Gpa.
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A shell of 4 m long, 1 m diameter is subjected to an internal pressure of 1 N/mm². If the thickness of shell is 10 mm; find the circumferential and longitudinal stresses. Find also the maximum shear stress and changes in the dimensions of the shell. Take E = 200 Gpa and poisson’s ratio = 0.3.
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