Finite element simulation of rotary blanking based on a modified GTN damage model

Based on the GTN model,a modified GTN model applicable to compressive stress conditions was established by considering the effect of microvoid shear deformation on the loss of load-carrying capacity. The elastic-plastic constitutive model with the damage model was implemented in finite element software Abaqus/Explicit with ALE description through user subroutine VUMAT.Parameter values of the modified GTN model in simulation were determined by fitting the load-displacement curve in tensile and pure shear tests. Then,the modified GTN model was employed in finite element simulation of rotary blanking processes to predict the sheared edge quality and the simulation results were experimentally verified. The results show that for the leading cutting edge where the clearance is small,the roll-over depth is small and the burnish depth tilting at an angle is large. For the tailing cutting edge where the clearance is large,the roll-over and fracture depths are large and the burnish depth is small. Microcracks will simultaneously initiate near the flanks of the punch and die for the leading cutting edge,while for the tailing cutting edge they will occur firstly near the flank of the die.