Advanced Modelling and numerical simulation of ductile damage in cold bulk metal forming
Résumé
Ductile (or plastic) damage often occurs during sheet or bulk metal forming processes due to the large plastic flow localisation. Accordingly, it is crucial for numerical tools, used in the simulation of that processes, to use fully coupled constitutive equations accounting for both hardening and damage. The present talk is dedicated to the presentation of the theoretical and numerical aspects of advanced, multiphysical and strongly coupled constitutive equations and their practical use for the “optimization” of various kinds of bulk metal forming processes. In a first part, the fully coupled constitutive equations are formulated, in the framework of the thermodynamics of irreversible processes with state variables, under large inelastic strains assumption and accounting for combined isotropic and kinematic hardening as well as the ductile damage considering the anisotropy of the inelastic flow and the ductile damage. The second part is dedicated to the associated numerical aspects in the framework of fully adaptive numerical methodology based on the finite element method with time and mesh adaptation in 2D cases. Finally, the third part is devoted to the simulation of various 2D and 3D examples where some bulk metal forming processes are simulated.