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Homework Help: Machine elements stress concentration

  1. Feb 14, 2016 #1
    1. The problem statement, all variables and given/known data

    A flat part with constant thickness b is loaded in tension as shown. The height changes from 50 to 87 mm with a radius r = 4.0 mm. Find how much lower a load can be transmitted through the bar if the height increases from 50 to 100 mm and the radius increases from 4.0 to 10 mm.


    2. Relevant equations

    σ = P/A = P/bh

    Kc = σmax/σave

    3. The attempt at a solution

    For the fist case, r/h = 4/50 = 0.08, H/h = 87/50 = 1.74, Kc = 2.5

    But I'm stuck because I don't know the material or the stress so I don't know how to determine the load. Do I even need the Kc value?
  2. jcsd
  3. Feb 15, 2016 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    The problem isn't asking you to calculate the actual stress or the actual load. You are not even given the thickness of the part.

    You should assume that both pieces are made from the same material, which will have the same strength. All you are asked to find is the load the modified piece can carry in relation to the original piece as shown.
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