Mechanics Of Solids -jan2003-or-220352

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Code No:220352 II.B.Tech II-Semester. Supplementary Examinations. January,2003 MECHANICS OF SOLIDS (Common to Mechanical Engineering, Mechatronics, Production Engineering, Mechanical Manufacturing Engineering) Time: 3 hours. Max.Marks:70 Answer any FIVE questions All questions carry equal marks. --1. A steel rod of 20mm dia and screwed at the end passes through a copper tube of 23 mm inner dia and 30mm outer diameter. The temperature of the whole assembly is raised to 395K and the nuts are tightened. Calculate the stresses if the common temperature falls to 310K. Coefficient of expansion for steel=11x10-6 per K. Coefficient of expansion for copper=19x10-6 per K. E for steel=2.05x105 N/mm2, E for copper=1.1x105 N/mm2. 2. Sketch the shear force and Bending Moment Diagrams and given all the salient values for the following beam. 20 kN 10 kN/m 10kN/m 2m 1m 1m 2m 3. A cast iron water pipe has 30cm bore and 1.5cm metal thickness and is supported at two points 8m apart. Find the maximum stress in the metal when it is running full. Take the unit weight of cast iron as 72 kN/m3 and that of water as 10kN/m3. 4. An I section of 10 cm width and 15 cm depth has flanges of 2cm thick on either side and a web of 1.4cm thick. Sketch the shear stress distribution diagram giving all the salient values. Also determine the ratio between the maximum and average shear stresses. 5. A simply supported beam of space 6m has a point load 20 kN at 4m from left support. Using mohr’s movement Area theorems obtain the deflections under point load and also the maximum deflection. Assume EI as uniform through out the beam. 6. A cast iron pipe has 30cm internal diameter and 40 cm external diameter and carries water under a pressure of 5 N/mm2. Calculate the maximum and minimum circumferential stresses and sketch the stress distribution curves across the wall thickness for radial and circumferential stresses. Contd…….2

Code No:220352

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7. Direct stress of 120 N/mm2 tension and 90 N/mm2 compression are applied to an elastic material at a certain point on planes at right angles. The greater principal stress is limited to 150 N/mm2. What shearing stress may be applied to the given planes. Also find the maximum shearing stress. Derive the expressions used for the principal stresses and the maximum shear stress. 8. A circular shaft supported in bearing 4m apart transmits 75 kW of power at 120 rpm. A pully provided at 1.5m from one bearing exerts a transverse load of 40 kN on the shaft. Determine the suitable diameter of the shaft if (i) The maximum direct stress is not to exceed 90 N/mm2 and (ii) The maximum shear stress is not to exceed 45 N/mm2. Tube

1 =0.25. m **********