An accurate and explicit approach to modeling realistic hardening-to-softening transition effects of metals

A finite strainJ(2)-flow model of von Mises type for elastoplastic behaviors of metals is proposed with a new characterization of the evolving yield strength. It is intended for providing solutions to a few unresolved issues concerning a simultaneous simulation of realistic hardening and softening effects for metals up to failure. Such issues are concerned with three respects, namely, how to ensure that the simulation is accurate in the sense that sufficient uniaxial experimental data for both hardening and softening effects can be matched with no errors, how to ensure that the simulation is explicit in the sense that any implicit trial-and-error iterative procedures in identifying numerous parameters can be bypassed, and how to ensure that the simulation is of broad applicability in the sense that any given uniaxial data for metals can be automatically matched. With the new model proposed, solutions to such issues are obtained by presenting an accurate and explicit form of the yield strength function that automatically matches any given test data. Numerical examples with realistic hardening-to-softening transition effects are presented for the first time for the finite strain responses of both uniaxial stretching and simple shearing up to the eventual failure.