In order to optimize the blanking processes, it is important to identify the conditions within the deforming workpiece which may lead to fracture initiation and propagation. Within this framework, numerical simulations are widely used in industries to optimize sheet metal forming processes. However, in order to have a conÿdence in the results of such simulations, an accurate material model is required. The accuracy of a material model is a ected by the constitutive equations and the values of the material parameters. In order to reduce the danger of fracture of metal parts during manufacturing processes, advanced optimal design requires knowledge of critical values of some fracture criteria of the material used. Experimental identiÿcation of fracture criteria are currently obtained by performing several complicated tests and long duration of experiments.
This study presents a computation methodology allowing for the identiÿcation of critical values of fracture criteria in order to simulate crack initiation and propagation generated by shearing mechanisms, which are needed for metal blanking processes simulation. The approach is based on inverse technique using circular blanking experiments and ÿnite element calibration model. The critical values of fracture criteria are obtained in such a way that the ÿnite element force-penetration predicted curve ÿt the experimental plot deduced from blanking tests. The numerical results obtained by the simulation were compared with experimental ones to verify the validity of the proposed technique for fracture criteria identiÿcation.