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Stress along a Beam

  1. Feb 23, 2007 #1
    I am using a cantilever beam, guided on one end and fixed on the other, (example 1b from Roark's Formulas for Stress and Strain), I have included the page from the book as an attachment.

    I want to determine an equation for the stress along the top of the beam.

    The beam is 250 mm long, 3 mm high, 25 mm deep.
    The modulus of elasticity E is 68927 N/mm^2
    The moment of inertia I is 56.25 mm^4
    a = 0

    From what I have been able to determine
    stress = (M*c)/I
    where M is the bending moment, c is the distance from the neutral axis to the proper fibers (therefore this is half of the height, 1.5 mm), and I is the moment of inertia.
    The bending moment is outlined in the attached file

    Is this correct or am I taking the wrong approach? I appreciate any help.

    Attached Files:

  2. jcsd
  3. Feb 24, 2007 #2


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    Homework Helper

    Well, you wrote down the relation between stress and the bending moment function, so try to work something out.
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