Modeling mixed hardening, of alkali halides with a modified version of an internal state variables model

In the ductile regime of inelastic flow, alkali halides behave similarly to various metals. Their behavior is fully plastic, shows strong rate and his tory dependencies, and exhibits anisotropic hardening. In this paper, the a uthors present the most recent version of SUVIC, a viscoplastic model with internal state variables (ISV). After recalling the main features of alkali halides inelastic response, the modified equations of the model are presen ted. They are then used to represent the behavior of polycrystalline sodium chloride submitted to conventional triaxial compression (CTC) and reduced triaxial extension (RTE) tests, using results that highlight mixed (kinemat ic and isotropic) hardening of the material, hence showing a type of Bausch inger effect. A discussion follows. (C) 1999 Elsevier Science Ltd. All righ ts reserved.