An implicit method for a strain rate dependent constitutive model implemented in AUTODYN as a user subroutine

An implicit numerical method for the strain rate dependent constitutive model by Johnson and Cook is described. It is implemented in AUTODYN-2D as a user subroutine. The reason for doing this is that the standard method sometimes leads to high frequency oscillations and underestimation of the influence of strain rate on the yield stress. The standard method, our implicit method as well as a new method (where also the mentioned problems are solved) included in the latest version of AUTODYN (v. 4.2, released autumn 2001) are compared.