Thanks Charles. I have gotten all the correct numbers in, manipulating the engineering stress/ strain curve to get true stress/true strain. Here is what I did:
I calculated the Ramberg Osgood Coefficient: n = (LN(eus/.2))/((LN(Ftu/Fty))
eus uniform strain
Ftu ultimate strength
Fty yield strength
Uniform strain can be calculated by: eus = 100(er-(Ftu/E))
er strain at rupture
E youngs modulus
I obtained an engineering stress strain curve using:
eeng = sigmaeng/E+.002*(sigmaeng/Fty)^n
I calculate true stress and strain
sigmatrue = sigmaeng*(1+eeng)
etrue = LN(1+eeng)
Then calculated true plastic strain
etrueplastic = etrue-(sigmatrue/E)
Does this seem correct? By the way all of this info can be found in MMPDS-01