A VISCOPLASTIC MODEL FOR SINGLE-CRYSTALS

A viscoplastic constitutive model is described in which deformation behavior is postulated on representative slip systems and the behavior of the entire crystal is determined by summing the slip on the active slip systems. By building in the slip geometry known from the metallurgical literature, it is possible to predict the anisotropic deformation behavior and to model in a straightforward manner other phenomena which have been described by metallurgists in crystallographic terms. Elevated temperature tension-torsion tests were run and used to verify the model's predictive abilities. Ratchetting behavior under thermomechanical loading conditions is specifically addressed.