A model for elastic-plastic pressure sensitive materials subjected to large deformations

Development of a finite deformation elasto-plastic model for pressure sensitive materials is presented. The chosen model, which has its roots in the MRS-Lade material model is influenced by recent developments. The thermodynamic consequences of introducing non-associative yielding (both deviatoric and volumetric) and hardening⧸softening characteristics are assessed. The consistently linearized Algorithmic Tangent Stiffness (ATS) tensor is presented. This tensor is used in the constitutive driver as a key feature of the efficient iterative procedure for satisfying equilibrium in the case of stress (or mixed) control.The chosen model is calibrated using data from experiments conducted in a Directional Shear Cell (DSC) , which has been used extensively at the University of Colorado at Boulderto investigate the behavior of pressure sensitive materials under deformations of large magnitude.