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Thread: Calculating Youngs Modulus

  1. #1 Calculating Youngs Modulus 
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    Hi all

    Just a quick query on how can I calculate Young's Modulus from a tensile strength graph (ie force / extension)?

    Would the easiest way be to convert this graph into a stress/strain graph so I can simply take the gradient?
    If so, how would I convert a force / extension graph to a stress / strain graph?

    Kind regards

    Anthony


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  3. #2  
    exchemist
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    Quote Originally Posted by AnthonyChan View Post
    Hi all

    Just a quick query on how can I calculate Young's Modulus from a tensile strength graph (ie force / extension)?

    Would the easiest way be to convert this graph into a stress/strain graph so I can simply take the gradient?
    If so, how would I convert a force / extension graph to a stress / strain graph?

    Kind regards

    Anthony
    Remind me, what are the units of stress and strain? That should help give us a clue.


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  4. #3  
    Bullshit Intolerant PhDemon's Avatar
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    Stress has units of pressure (it is the force divided by cross-sectional area), strain is dimensionless, it is the extension divided by the length.

    Does this help you Anthony?
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  5. #4  
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    Thank you that's excellent!

    I should have done the math with the units first to work that out.

    I am going to simply use a secant line to take the gradient from the graph, so would I be ok to just convert the (x y) points as I'm calculating?
    ie, (delta y / cross sectional area) / (delta x / L).

    Kind regards

    Anthony
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  6. #5  
    Bullshit Intolerant PhDemon's Avatar
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    That should be fine if the cross-sectional area is constant.
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  7. #6  
    exchemist
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    Quote Originally Posted by AnthonyChan View Post
    Thank you that's excellent!

    I should have done the math with the units first to work that out.

    I am going to simply use a secant line to take the gradient from the graph, so would I be ok to just convert the (x y) points as I'm calculating?
    ie, (delta y / cross sectional area) / (delta x / L).

    Kind regards

    Anthony
    Do you have the cross-sectional area? I can see that you have all the rest.
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  8. #7  
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    Yes I have the cross sectional area from the test pieces. Thank you very much for the info!

    Much appreciated!

    Kind regards

    Anthony
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