calculation of tangent modulus

[mon1299]

Hi everyone,
I am trying to model bilinear isotropic material in ansys. I have data yield stress=50ksi, ultimate strength=64ksi,E=29000ksi Elongation%=27.I wanna calculate tangent modulus. I dont know wheather I can calculate it or not. Is there anyone who can help me in this regard? If its not possible to calculate from these data, can I use Et=Ei? Is this assumption conservative?I am really stucked with this problem and cant proceed further. Any kind of advice is welcome. I really need that.
thanx in advance.
worried
papia

 

[Qshake]

If your material has a constantly changing curve to represent a stress-strain relationship, then perhaps you should consider representing it in two distinct parts.

the first part is the secant modulus which always begins at the origin. The second part from yield stress to the ultimate stress(tangent modulus).

You can arrive at such an appoximation by graphically plotting using a best fit.

Alternatively, check literature on the subject since some materials have well accepted critieria for these lines. For example, concrete is best described by a line from the origin to 0.4 ultimate stress and from 0.4 to ultimate.

Regards,
Qshake

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