The numerical method for predicting failure in single point incremental forming using a new anisotropic ductile fracture model

Abstract

Abstract Although single point incremental forming (SPIF) possesses various advantages such as great simplicity and high flexibility, the major limitation is failure and fracture that result from extreme thinning along the thickness direction for complex sheet metal parts. So it is necessary and important on investigating the deformation modes and predicting failure and fracture. In this study, the Hu-Chen ductile fracture criterion (DFC) is modified by tensor transformation, then a new anisotropic ductile fracture criterion is proposed. And the new anisotropic ductile fracture criterion is implemented into Abaqus/Explicit by a user subroutine VUSDFLD. Based on the fracture strain measured from experiments, the parameters of anisotropic DFC can be determined by minimizing the system of nonlinear functions using the nonlinear least-square method, so that the calibrated anisotropic ductile fracture model can be applied into finite element simulations of SPIF. The stress and strain states of the deformation field in FE simulations of SPIF are comprehensively analysed. The new anisotropic ductile fracture model on predicting failure behaviours in SPIF is assessed by the comparisons between simulations and experiments for the parts.