Numerical pressure prediction algorithm of superplastic forming processes using 2D and 3D models

The paper describes a finite element model allowing for the prediction in a rapid way the optimum pressure cycle law, the deformed shapes, the distrib utions of the strain rate and the evolution of the thickness during superpl astic forming processes. During the calculation, a pressure-cycle control a lgorithm is used in the analysis which keeps track of the maximum strain ra te sensitivity index m, and adapts the pressure law applied in order to app roach as nearly as possible the optimal pressure time history law. The purp ose is not to follow the target exactly but obtain a practical. pressure ti me history in a low computation cost time. To compare the performance of 2D and 3D approaches, two analyses have been performed using 2D and 3D finite element modeling. The numerical results are compared with the experimental ones to verify the validity of the pressure algorithm control. (C) 2001 El sevier Science B.V. All rights reserved.