# Thread: Calculating Youngs Modulus

1. 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  2.

3. Originally Posted by AnthonyChan 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.  4. 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.  5. 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  6. That should be fine if the cross-sectional area is constant.  7. Originally Posted by AnthonyChan 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.  8. Yes I have the cross sectional area from the test pieces. Thank you very much for the info!

Much appreciated!

Kind regards

Anthony  Bookmarks
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