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Homework Help: Normal stress on cantilever beam

  1. Sep 26, 2011 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    [tex]\sigma_x = -\frac{M(x)y}{I}[/tex]

    [tex]I = \frac{bh^3}{3}[/tex]

    3. The attempt at a solution

    For point A, I did the following:

    [tex]I = \frac{t(2h)^3}{3}[/tex]

    [tex]I = \frac{8th^3}{3}[/tex]

    [tex]\sigma_x = -\frac{3\tau_0}{4th}[/tex]

    [tex]\tau_{yx} = -\tau_0[/tex]

    [tex]\sigma_y = 0[/tex]

    Are my principal stresses correct for point A? Also, would these principal stresses be the same for Point B?
  2. jcsd
  3. Sep 27, 2011 #2


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    Science Advisor
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    Gold Member

    A principal stress state contains no shear. Also, it's hard to imagine why A and B would be equivalent when the applied traction is creating a moment around the fixed end of the beam.
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