Properties of Steels for Nonlinear FEA
In my opinion, this is not going to be easy to find. Most of these data are available with the big organizations that use it everyday for their work. I was told that MSC in assoc. with some company in Detroit is trying to tabulate a good database. Maybe u can contact MSC. else the best way is to do a coupon test on the metal that you are interested in. I am not sure power law is a good way to model the behavior of metal in their post-elastic zone. As with computers junk in = junk out in FEA too.