Section A
Q1.
(a) In a tension test, a steel rod of gauge length 255 mm and diameter 32 mm was used. The rod during the test was stretched 0.108 mm under a pull of 65 kN. In a torsion test, the same rod was twisted 0.018 radian over a length of 255 mm at the torque of 500 × 103 N-mm. Determine the modulus of elasticity, modulus of rigidity, Poisson's ratio and bulk modulus.
(b) The tension in cable BC is 750 N. Determine the resultant of the three forces exerted at point B of the beam AB :
(c) Determine the vertical movements of joint C of the truss shown in the figure below, if the member FG is lengthened by 55 mm. Use the principle of virtual work :
(d) Using the unit load method, determine the vertical and horizontal deflection of the free end of the frame as shown in the figure below. Support A is fixed, B is rigid joint and point C is free. BC = I and BA = 2I. Take E = 210 GPa and I = 300 × 10-6 m4 :
(e) With the help of neat sketches, explain the stress concept and load-balancing concept of prestressing.