MATERIAL CHARACTERIZATION FOR THE PREDICTION OF DUCTILE FRACTURE OCCURRENCE - AN INVERSE APPROACH

The most advanced approach to the prediction of ductile fracture occur rence in metal forming processes is represented by a damage mechanics formulation. Such an approach requires a suitable evaluation of the pa rameters which appear in the yield condition for the damaging material and in the model which governs the evolution of microvoids (nucleatio n, growth and coalescence), which allow to calibrate the model with re spect to the actual state and properties of the material. In the paper this aim is pursued employing an inverse identification approach base d on an optimization technique which permits to adjust the material va riables so that the numerical response matches the experimental one. I n particular the load vs. displacement curve during a tensile test has been used to optimise the comparison between the numerical and the ex perimental results and to develop a full damage characterisation of th e material.