Sheet Metal Blanking Modeling Using Lode-Dependent Plasticity and Ductile Damage Models Combined with 3D Adaptive Remeshing Method

Abstract This paper is devoted to numerically study the sheet metal blanking process using elastic-visco-plastic model fully coupled with ductile damage and 3D adaptive remeshing procedure. The proposed constitutive theory aims to capture the effects of irreversible damage associated with the failure mechanisms that occur in sheet metal forming under large deformation. The isotropic ductile damage fully coupled into an elasto-viscoplastic flow stress model and stress state parameters (stress triaxiality and Lode angle) are proposed to control the damage evolution under multi-axial loading path. When a sheet metal is sheared by large elastic-viscoplastic strains, the propagation of macroscopic cracks induces severe changes of topology and frequent remeshing must be performed in order to avoid large mesh distortion and element quality. An h-adaptive Constraint Delaunay kernel remeshing scheme (refinement and coarsening) dedicated to the simulation of macroscopic ductile cracks initiation and propagation during blanking processes is proposed. Cracks are represented using a procedure based on fully damaged elements deletion. Optimal adaptive element size is driven by error indicators based on both geometrical considerations (tool geometry, deformed part) and the derivatives of physical field (plastic strain or damage localization). The proposed methodology was successfully verified comparing the predicted evolution of material ductility with the experimental data relative to several metals. The procedure for the blanking simulation is also discussed in details.