NUMERICAL SIMULATION OF BURSTING IN EXTRUSION PROCESS USING FINITE VISCOPLASTICITY WITH DUCTILE DAMAGE AND THERMAL EFFECTS

This paper focuses on the numerical simulation of the chevron shaped cracks in cold extrusion using thermoelastoviscoplaticity with ductile damage and thermal effects. A multiphysical constitutive model accounting for non-linear isotropic and kinematic hardening together with the ductile isotropic damage initiation and growth is used in the framework of large inelastic strain and small elastic strain. The associated numerical aspects are shortly described and the material parameters are identified based on 100Cr6 steel experimental data base taken from the literature. A special care is given to the "parametric" study of the influence of some extrusion parameters on the 'discontinuous' formation of central bursts, particularly the effects of the die angle, the friction coefficient, the material ductility and the punch velocity.