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Homework Help: Normal/Shear stress & Von Mises analysis

  1. Apr 20, 2010 #1
    Hello all,

    I am working on a design project (school work, nothing too important) and I'm trying to wrap my head around how to analyze potential failure in a shaft with an applied tensile load at one end and a torque near the midpoint. (The beam is fixed at the other end.) The tensile force is an axial load. http://imgur.com/BeA0e.png"

    Looking at the Von Mises equation, things simplify down to a single normal stress in the axial direction and a singe shear stress.

    What I'm not sure about is the portion of the beam beyond the point where the torque is applied. I understand that the shaft does not continue to twist beyond this point, but is there still a shear stress in this portion of the shaft? If the answer is no, as I suspect it might be, the effective stress given by the von mises equation simplifies to the single normal stress in the x-direction.

    Thanks for the help, sorry if this should have been posted in the mech. eng. section.
    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Apr 20, 2010 #2
    I guess I'll reword my most basic question.

    Let's say you have a shaft fixed at one end, free at the other. If you apply a torque at the midpoint, will there be a shear stress anywhere between where the torque is applied and the free end of the beam?

    In this problem, if there isn't a shear stress in that portion of the shaft, both the Von Mises equation and the Principal Stress equation simplify down to the single normal stress (due to the axial load).
  4. Apr 21, 2010 #3


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    Your intuition is right; there is no shear stress between points B and C, only normal stress.
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