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Need to calculate psi

  1. Sep 14, 2016 #1
    We performed an experiment on a rectangular box of measured dimensions made from a certain material. We loaded the box with weights until mechanical failure. So, I know the dimensions of the box and the amount of force put on it until it failed. Would I be able to accurately calculate and report the psi of the material we used by simply calculating the surface area of the box and doing the math? Or, is this test inaccurate because the point of mechanical failure might be dependent on the geometry of the rectangular box?
     
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  3. Sep 14, 2016 #2

    Mech_Engineer

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    Was this experiment designed to test the strength of the component? Or was it happenstance that you applied too much weight and it failed?
     
  4. Sep 14, 2016 #3
    It was designed to test the strength of the component.
     
  5. Sep 14, 2016 #4

    Baluncore

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    The answer is almost certainly NOT based on the surface area of the top of the box. The method would depend on how the weight was applied to the box. For example the top of the box might fail due to point loads of the applied weight.

    If the box was loaded symmetrically then all the walls would have been under compression. If the walls were then crushed, and so failed without buckling, the “psi” would be the total weight in pounds, divided by the cross sectional area of the walls measured in square inches.

    You need to give a lot more information about dimensions, material and mode of failure before a reliable answer can be given.
     
  6. Sep 15, 2016 #5

    Mech_Engineer

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  7. Sep 16, 2016 #6
    Please describe the nature of the failure.
     
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