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Homework Help: Finding yield stress with only modulus of elasticity and Poisson's ratio?

  1. Mar 13, 2006 #1
    Is it possible to find the yield stress of a material with only modulus of elasticity and Poisson's ratio?

    I was given a problem that:
    What is the min. aluminum needed to support a block (10 Newton) to 1 meter high? E=70GPa and v=0.3 are the only given aluminum properties.

    I would know how to solve it if I knew the yield stress.
    Can anyone give me some help?

    (I know the yield stress for Al is usually around 270-275, but let's pretend we don't know that).

    Thanks a lot!
    Leo

    -----------------------------------
    This is what I have so far:
    use Hooke's Law for strain x, y, and z.
    stress x = stress z = 0; stress y is in the vertical direction.
    strain x = strain z = (-v*stress_y)/E

    and I'm stuck...

    Thanks.
     
    Last edited: Mar 14, 2006
  2. jcsd
  3. Mar 14, 2006 #2

    EQ

    User Avatar

    I would use Area=(PL)/(Epsilon*E)

    Hope that helps
     
  4. Mar 14, 2006 #3
    Thanks for the reply.
    I might be missing something, but I don't know how to get the strain "Epsilon".
     
  5. Mar 18, 2006 #4

    FredGarvin

    User Avatar
    Science Advisor

    What application is the problem centered around? A beam? A column? The way you have things worded here it's impossible to help you with your question.
     
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