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Stress-strain curve

Stress-strain curve

Stress-strain curve

I got misunderstanding in stress-strain curve for steel ,I have two references for steel stress-strain curve one of them  shows the fracture points for both (true, engineering)at the same strain. While the other reference has a figure for steel stress-strain curve but the true and engineering fracture point are not at the same strain.

Which reference is perfect ?

RE: Stress-strain curve

Since true strain and engineering strain are not equal quantities, obviously the material must fracture at a point with different values of engineering and true strain.



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RE: Stress-strain curve

True strain or engineering strain quantities are used for specific engineering applications, and both are considered acceptable for use.

RE: Stress-strain curve

An additional clarification to my post above is that a true engineering stress/strain curve may be used for specific engineering applications, while an engineering stress strain curve is probably more widely used for comparison of mechanical properties in technical literature. Both curves are considered equally acceptable for use, one just has to remember that the quantities are not the same for comparison.

RE: Stress-strain curve

why the fracture point in ture curve happen at strain lower than engineering curve

RE: Stress-strain curve

I would go back and re-evaluate your plotted data.

By definition  

true strain = ln (1 + engineering strain)


true stress = engineering stress (1 + engineering strain)

True strain is an additive quantity based on the above definition, so I don't see how the engineering strain could exceed true strain in a standard tensile test for metals.

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