FINITE ELEMENT ANALYSIS OF SHEET-METAL PUNCHING PROCESSES

R. Hambli 1,2 , A. Potiron 1

1 Ecole Nationale Superieure d'Arts et Metiers, France ; 2 Institut des Sciences et Technique de l'Ingenieur d'Angers - LASQUO, UPRES JE 2039, France

In order to accurately simulate sheet-metal cutting processes by material shearing mechanisms, such as blanking and punching operations, a finite element model has been developed valid for the numerical description of such processes. Damage and cracks propagation have been taken into account by means of an elastoplastic constitutive law.
To study the effects of processes parameters variation on the geometry of the sheared edges and the force-punch penetration evolution, a specific algorithm has been implemented by means of the user's routine (UMAT) of ABAQUS/Standard finite element code.
During the analysis, the initiation of crack is supposed to occur, at any point in the structure where the damage reaches its critical value Dc. The crack propagation is simulated by the propagation of a completely damaged area. This is taken into account in the F.E.M by decreasing the rigidity of the elements subjected to critical damage.
The numerical results obtained by numerical simulation were compared with the experimental ones in order to verify the validity of the proposed finite element model.

Keywords:Punching, Blanking, tool wear, finite element, experiment.