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Thread: Modulus of elasticity

  1. #1
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    Modulus of elasticity

    Right I have numbers in front of me that someone has asked me to figure out Young's modulus from them.
    The original length of the unknown material is 70mm, the diameter is 113mm, the load is 100kN and the material extends by 0.5mm at the point. How ever the problem is every time I figure it out I get the same answer but to my knowledge the is no known material to have a modulus of elasticity of 1395.99kN/mm^2. Can anyone see if they can get a more rational answer to this problem?

  2. #2
    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Mrscience View Post
    Right I have numbers in front of me that someone has asked me to figure out Young's modulus from them.
    The original length of the unknown material is 70mm, the diameter is 113mm, the load is 100kN and the material extends by 0.5mm at the point. How ever the problem is every time I figure it out I get the same answer but to my knowledge the is no known material to have a modulus of elasticity of 1395.99kN/mm^2. Can anyone see if they can get a more rational answer to this problem?
    Young's Modulus is:

    youngs-modulus.png

    where
    E is the Young's modulus (modulus of elasticity)F is the force exerted on an object under tension;A0 is the original cross-sectional area through which the force is applied;ΔL is the amount by which the length of the object changes;L0 is the original length of the object.

  3. #3
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    Quote Originally Posted by Kelly Bramble View Post
    Young's Modulus is:

    youngs-modulus.png

    where
    E is the Young's modulus (modulus of elasticity)F is the force exerted on an object under tension;A0 is the original cross-sectional area through which the force is applied;ΔL is the amount by which the length of the object changes;L0 is the original length of the object.
    Yes I understand the equations involved and how to find both stress and strain my problem occurs once I've carried out all of the calculations, I get the value of E to be greater than that of diamond which by my knowledge is impossible.

  4. #4
    Engineer PierArg's Avatar
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    Hi,
    are you sure that your material, under the load, has only an elastic deformation?
    I suppose the formula posted by Kelly Bramble is valid just for elastic behavior.

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