2. Introduction

This document describes the integration of viscoplastic behavior law VISC_DRUC_PRAG into Code_Aster. This law includes a single viscoplastic mechanism. The viscoplastic criterion collapses with the cumulative deviatoric viscoplastic deformation by passing through three thresholds: elastic for zero viscoplastic deformation, a so-called peak threshold for a viscoplastic deformation called peak (model parameter) and an ultimate threshold for a so-called ultimate viscoplastic deformation (model parameter). Between the thresholds, the work hardening functions are linear. In Code_Aster there is another law based on the Drücker_Prager model and used in elastoplasticity in an associated form under the name DRUCK_PRAGER or not associated under the name DRUCK_PRAG_N_A (see [R7.01.16]).