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Homework Help: Shear stress in beam

  1. May 3, 2010 #1
    1. The problem statement, all variables and given/known data

    Determine the Max, Min & average shear stress, and the shear force in web

    V = 125kN

    Note th attachment

    2. Relevant equations

    3. The attempt at a solution

    First I calculated the Moment of Inertia

    I = (1/12)(bh3 - bh13 + th13) = 3.43X10-4 m4

    Max Shear Stress = (Vb/8It)(bh2 - bh12 + th12) = 28.4MPa

    Min Shear Stress = (V/8It)(h2 - h12) = 21.9MPa

    Avg Shear Stress = (V/th1) = 27.4MPa

    Vweb = (th1/3)(2[tex]\tau[/tex]max + [tex]\tau[/tex]min) = 119.6 kN

    Did I use all the correct equation. The example uses these equations but says they are in the web.

    Attached Files:

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  2. jcsd
  3. May 4, 2010 #2


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    Science Advisor
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    I guess if you are just using some given formulas ( corrected for typo errorrs) for max, min, avg shear stresses in a web and plugging in numbers, then there's not much I can say. Far better to understand the shear stress formula using the first moment of area Q. Otherwise it's just plug and chug.
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