Simulation of Crack Initiation and Propagation in Blanking of Sheet Metal

Numerical simulation of crack initiation and propagation in a blanking process of a steel sheet is done using rigid plastic finite element code developed by the authors. The modified Cockcroft and Latham expression is used as a ductile fracture criterion and is linked with the simulation. It is assumed that when the fracture threshold is satisfied at an element, a crack occurs and propagates through the element. The node separate method is proposed as a method for simulating the crack propagation. To confirm the results of finite element simulation, blanking experiments are also carried out under various conditions, and the crack propagation with punch penetration and the shape of cut edge are observed. The experimental results show good agreement with those of the simulation.