Tensile Strain, Elongation units from a percentage?

Ryan Manning

New member
I am 90% sure I am on the right track to working out the Modulus of Elasticity for a tensile test.

I need to know a bit more about Strain, elongation and extension.

To get the Modulus of Elasticity I have to calculate Stress divided by Strain in my case Stress = 355MPa but the strain is hard for me to work out.

I know the formula but I guess I am doing something wrong. If my total elongation is 10/50 that equals 20% elongation but All of the graphs that I have come across show the strain figures to be 0.002, 0.004, 0.006, 0.008, 0.01, 0.012 and so on.

I think 20% can also be expressed as 0.20 and if i measure the point of my elastic limit proportionally to 0.20 as the total elongation it equals to 0.04.

For Modulus of elasticity if I calculate 355 divided by 0.04 = 8875 MPa (or 8.75 GPa)
but if somehow the strain figures had another 0 such as 0.004, 0.006, 0.008 etc then my calculations would work out.

355 Divided by 0.004 = 88750 MPa (or 88.75 GPa) which is in the range for the Modulus of Elasticity for Brass.

In Summary I know the total elongation amount is 20% but how can I express these figures as 0.002, 0.004 (etc)

I guess I can't post any images here of my graph but my email address is [email protected] and if you are able to email me I can send you the graph.

Thank you.
 
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