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Homework Help: Thick Cylinders

  1. Sep 29, 2009 #1
    1. The problem statement, all variables and given/known data

    A thick cylinder of 100mm internal radius and 150mm external radius is subjected to an internal pressure of 60MN/m^2 and an external pressure of 30MN/m^2. Determine the hoop and radial stresses at the inside and outside of the cylinder together with the longitudinal stress of the cylinder is assumed to have closed ends.

    2. Relevant equations

    radial stress = A - B/r^2

    3. The attempt at a solution

    Ok so we've got:

    at r = 0.1m, radial stress = -60MN/m^2
    at r = 0.15m, radial stress = -30MN/m^2

    Therefore using the equation:
    radial stress = A - B/r^2

    we get -60 = A -100 B
    -30 = A - 44.5 B

    I don't know how they got the 100 and 44.5 here? Quite confused
  2. jcsd
  3. Oct 4, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    That's right.

    All your other equations appear to make no sense and are incorrect. You would need to post coherent relevant equations, and a coherent, valid attempt, in order to receive help.
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