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Direct stress and elongation

  1. May 25, 2008 #1
    A prismatic bar AB of length L, cross-sectional area A ,modulus of elasticity E ,and weight W hangs vertically under its own weight
    a>derive a formula for the downward displacement d(c) of point C which is located at a distance l from the lower end of the bar

    The answer is W(L^2-l^2)/(2EA)

    how do we get it?

    Thanks for any hints or answers!
  2. jcsd
  3. May 25, 2008 #2
    Well, so delta = PL/EA

    So P varies along the y direction...P = W*y/L, right?

    and if we're doing incremental displacement changes, the L is your dy

    d delta = integral W*y/LEA * dx

    so you integrate from your l to L. Shouldn't your answer also have an L term in the denominator?
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