Finite anisotropic plastic flow with ductile damage for sheet metal forming simulation

Abstract

This chapter presents a numerical methodology that aims to improve any sheet metal forming process with respect to the ductile damage occurrence. This methodology is based on finite anisotropic elastoplastic constitutive equationsaccounting for nonlinear mixed isotropic and kinematic hardening “strongly” coupled with isotropic ductile damage. It is well-known that in many bulk or sheet metal forming processes, the metallic material is subjected to large irreversible deformations, leading to high strain localization zones and then internal microdefects (ductile damage). This damage initiation and its evolution cause the quality problems of the formed piece that is rejected before its use. The used finite anisotropic elastoplastic constitutive equations, coupled with the isotropic ductile damage, are developed through the classical thermodynamics of irreversible processes with state variables. The chapter discusses the purely mechanical phenomena without thermal aspects by considering large anisotropic plastic (Hill's quadratic criterion). With respect to the finite plastic strain, several classical assumptions are made.