Finite Element Simulation of Edge Fracture by Mapping the Shear-Induced Ductile Damage into Hole-Expansion Simulation

A ductile fracture criterion (uncoupled type, originally presented at ICTP2017), which is endowed with both stress triaxiality (T) and Lode parameter (L) dependence, is selected to define the ductile damage accumulation from hole-blanking simulation to the subsequent hole-expansion simulation for a DP780 sheet. The calibrated ductile fracture criterion yields an asymmetric 3D fracture surface, which can well describe the material’s ductility within a wide range of stress states from simple shear to balanced biaxial tension. With the help of a fully integrated simulation framework, the ductile damage induced by the hole-blanking is completely mapped into the hole-expansion simulation to incorporate the pre-damage field for the sheared edge. We find that after considering the pre-damage field, the accuracy of edge fracture simulation is significantly improved in terms of both hole-expansion ratio and fracture propagation path.