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Homework Help: Mechanics of Materials - Help

  1. Nov 14, 2011 #1
    1. The problem statement, all variables and given/known data

    A hollow shaft has torque being applied on both sides. The angle of twist is 50 degrees, the diameter is 100 mm, the thickness t has 5 mm. We are given that the allowable stress is 120 MPa, and the allowable shear stress is 50 MPa.

    We are asked to solve for the maximum torque.

    I know I will have to calculate for the torque using two equations and I will have to compare the answers. I will find torque using the max stress and i will find torque using the maximum shear stress.

    At first:

    I used, Shear stress (max) = Tr/J

    J = TT/2 * (ro^4 - ri^4)

    I get the wrong answer.. I am wondering what the relation is with Torque and Angle of twist

    I know, theta = TL/JG . But I'm not given L, and not told what material I have, so G is unknown.

    Thank you for all the help!!
  2. jcsd
  3. Nov 16, 2011 #2
    Is this the exact problem statement?

    A shaft that can deflect 50 degrees seems very unrealistic, unless its made of play-doh:)

    Are they're no other figures given, perhaps a shear-stress diagram?

    Also if its asking for the maximum torque, then that torque just equals whatever the applied torque is at the ends (since these are the only torques).

    If you still need help type in the exact problem state and we can see what we can do
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