Answer ALL Questions
PART A – (5 x 2 = 10 Marks)
1.      A circular rod 2 m long and 15 mm diameter is subjected to an axial tensile load of 30 KN. Find the elongation of the rod if the modulus of elasticity of the material of the rod is 120 KN/mm2.
  1. What is thermal stress?
3.      A cantilever beam of 3 m long carries a load of 20 KN at its free end. Calculate the shear force and bending moment at a section 2 m from the free end.
4.      Sketch (a) the bending stress distribution, (b) shear stress distribution for a beam of rectangular cross section.
5.      Find the torque which a shaft of 50 mm diameter can transmit safely, if the allowable shear stress is 75 N/mm2.
6.      Differentiate open coiled helical spring from the close coiled helical spring and state the type of stress induced in each spring due to an axial load.
7.      A cantilever beam of spring 2 m is carrying a point load of 20 KN at its free end. Calculate the slope at the free end. Assume EI=12 x 103 KN-m2.
  1. Compare closed and open coiled helical springs.
9.      Compare thin cylinder and thick cylinder.
10.  A spherical shell of 1 m diameter is subjected to an internal pressure 0.5 N/mm2. Find the thickness if the allowable stress in the material of the shell is 75 N/mm2.

PART – B( 5×16=80 Marks)
Answer all questions

11.  (i) Define the modulus of rigidity and Poisson’s ratio.                                                           (4)
(ii) A bar 30 mm in diameter was subjected to a tensile load of 54 KN and measured extension on 300 mm gauge length was 0.112 mm and change in diameter was 0.00366 mm. calculate the Poisson’s ratio and the values of three elastic modulii.                                                                           (12)
{OR}

(b). A reinforced concrete column 500 mm x 500 mm in section is reinforced with 4 steel bars of 20 mm diameter, one in each corner. The column is carrying a load of 750 kN. Determine the stresses in concrete and steel bars. Take Es = 210 GPa and Ec = 14 GPa. Also, calculate load carried by steel and concrete.                                                                                                                                    (16)

12.  (a) A beam of length 10 m is simply supported at its ends carries two concentrated loads of 5 KN each at a distance of 3 m and 7 m from the left support and also a uniformly distributed load of 1 KN/m between the point loads. Draw the shear force and bending moment diagrams. Calculate the maximum bending moment.                                                                                                                 (16)
[OR]
(b)     A timber beam of rectangular section is to support a load of 20 KN uniformly distributed over a span of 3.6 m, when the beam is simply supported. If the depth of the section is to be twice the breadth and the stress in the timber is not exceed 7 N/mm2, find the breadth and depth of the cross section. How will you modify the cross-section of the beam, if it carries a concentrated load of 30 kN placed at the mid-span with the same ratio of breadth to depth.                                                                      (16)


  1.   (a) Calculate the power that can be transmitted at a 300 rpm by a hollow steel shaft of 75 mm external diameter and 50 mm internal diameter when the permissible shear stress for the steel is 70 n/mm2 and the maximum torque is 1.3 times the mean. Compare the strength of this hollow shaft with that of an solid shaft. The same material, weight and length of both the shafts are the same. (16)
[or]
(b)   A helical spring of circular cross section wire 18 mm in diameter is loaded by a force of 500 N. The mean coil diameter of the spring is 125 mm. The modulus of rigidity is 80 KN/mm2. Determine the maximum shear stress in the material of the spring. What number of coils must the spring have for its deflection to be 6 mm?                                                                                                        (16)
14.  (a) A simply supported beam of span 8 m is subjected to concentrated loads of 24 kN, 48 kN and 72 kN at 2 m, 4 m, 6 m from left support respectively. Calculate the slope and deflection at the centre and also find maximum deflection.(any one method)                                                                             (16)
{OR}
(b)A 3 m long cantilever of uniform rectangular cross section 150 mm wide and 300 mm deep is loaded with a point load of 3 KN at the free end and a UDL of 2 KN/m over the entire length. Find the maximum deflection E = 210 KN/mm2. Use Macaulay’s method.                                            (16)
      15. (a)A steel cylinder shell 3 m long which is closed at its ends, had an internal diameter of 1.5 m and a wall thickness of 20 mm. Calculate the circumferential and longitudinal stress induced and also the change in dimensions of the shell if it is subjected to an internal pressure of 1.0 N/mm2. Assume the modulus of elasticity and Poisson’s ratio for steel as 200 KN/mm2 and 0.3 respectively.                 (16)
                                                 [or]

(b)Derive relations for change in dimensions and change in volume of a thin cylinder subjected to internal pressure P.                                                                                                                            (16)