Questions on Stresses




  •        Consider two beams A & B. Beam A and B are positioned in horizontal direction and vertical direction respectively. Breadth of both beams is 2 cm. Initially the setup was at a stable environment of temperature 38o C but suddenly the temperature hits 120o C. Beam A is weightless and beam B has a weight of W. Find the deflection of beam A.
    EA=2x105 N/mm2; EB=9.65x106 N/mm2

  •          Consider the following:
    Two poles each carrying thick circular cross-sectional wires of diameter 2 cm are separated by a distance of 10 m. The two wires are initially loosened such that they can be imagined to be segments of a circle of radius R. Conditions arises such that the upper wire receives heat and lower wire rejects heat. The initial temperature of both the wire is same and the amount of heat absorbed and rejected by the wires is same. Both wires are carrying current I. Find the maximum temperature such that both the wires just prevents from getting touched.
    Coefficient of thermal expansion=α
    E (upper wire) =E (lower wire) =2x105 N/mm2
·       
  • An automobile has a brake drum arrangement, which comprises of a circular drum of effective radius 0.75 m. A rectangular brake pad of thickness 10 mm is placed at a distance from brake disc such that when brake is applied the pad touches the brake disc and the wheel travels a stopping distance of 1.75 m without slipping. Initially the pad was with thermal equilibrium with the surrounding and was at 38oC and after the braking effect the final temperature of pad hits 89o C. Find the volumetric expansion of brake pad.
         Length and breadth of brake pad are 10 cm and 5 cm respectively.
              x indicates frictional surface. µs=0.8; µk=0.6; E (brake pad) =0.96x103 N/mm2;          coefficient of thermal expansion=α

  •       Consider two sections 1 and 2 of infinitely long rectangular pipe enclosing a rectangular block oscillating between points A & B with a clearance of 4.5 mm from both sides. Due to the frictional surface of the pipe the temperature of the block raises by T. Find the time taken by the rectangular block to stop its oscillation. Length of section between 1 and 2 is 2.75 m. length and height of block =7.87 cm and 6 cm. Breadth of pipe 8 cm. Coefficient of thermal expansion of block=α.
         x  indicates frictional surface. µs=0.9; µk=0.75


  •       Three stairs are arranged of indicated material is shown. Three men are standing of varying weight. The breadth and height of each stair is 15 cm and 13 cm respectively. The temperature falls by 2o C. Find the ratio of strain between steel and brass. The coefficient of thermal expansion of steel, aluminum and brass and Young’s modulus are αS, αA, αB and ES, EA, EB respectively.
         Assume that the weight of each man is spread evenly upon the surface they are standing.

  •     Consider the following arrangement:
         A rectangular beam of length 0.45 m is hinged by a pin joint on a vertical was and the other end is fitted on a roller support which can have a translation motion on a frictional surface. The inclination angle β is 38.5o. The temperature raises by 187o C. Find:
    §  Stress attained if another vertical wall is located at a horizontal distance of 1.02 m from the upper hinged end of the beam
    E (rectangular beam) =2x105 N/mm2. µs=0.8; µk=0.65; cross-sectional area of beam=0.89 m2
        The temperature such that the lower end of the beam has translation motion.








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Comments

  1. Unknown14 August 2016 at 00:15

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