Optimization of Forging Preforms by Using Pseudo Inverse Approach

Abstract

A simplified method called “Pseudo Inverse Approach” (PIA) has been developed for axi-symmetrical cold forging modelling. The approach is based on the knowledge of the final part shape. Some intermediate configurations are introduced and corrected by using a free surface method to consider the deformation paths without classical contact treatment. A new direct algorithm of plasticity is developed using the notion of equivalent stress and the tensile curve, which leads to a very fast and robust plastic integration procedure. Numerical tests have shown that the Pseudo Inverse Approach is very fast compared to the incremental approach. In this paper, the PIA will be used in an optimization loop for the preliminary preform design in multi-stage forging processes. The optimization problem is to minimize the effective strain variation in the final part and the maximum forging force during the forging process. The numerical results of the optimization method using the PIA are compared to those using the classical incremental approaches to show the efficiency and limitations of the PIA.

A Pseudo Inverse Approach with Kinematically Admissible Intermediate Configurations for the Axi-Symmetrical Cold Forging Modelling

“…The classical incremental methods are widely used for the forging simulation and optimization [1][2][3]. Very advanced works have been done by Chenot, Fourment et al from CEMEF in France and the corresponding software product FORGE® is largely used in the forging industry [7,8]. However, the incremental methods are time consuming due to the numerous calculation steps.…”

Damage Prediction in Metal Forming Process Modeling and Optimization: Simplified Approaches

“…The constraint can be that all FLD points are situated below the FLC curve. In the case of forging, the constraint functions can be the conditions on the damage, wrinkling, filling, and volume (Meng et al 2012;Halouani et al 2012b): the maximal damage should be inferior to the damage threshold, the contour of the forged part should not have sudden changes (folding), the volume should remain constant, etc.…”

“…Among the stochastic methods, the genetic algorithms and the simulated annealing algorithms are largely used (Fourment et al 1996;Castro et al 2010;Meng et al 2010) to determine the Pareto front points and then to find the optimal solution according to other technological constraints. However, these algorithms are time-consuming; it is indispensible to reduce the number of design variables and to use a fast forming solver (Halouani et al 2012b). …”

“…The following objective function was used to minimize the strain variance (Meng et al 2010;Halouani et al 2012b):…”

“…The PIA has been used for the automatic design and optimization of tool preforms. Genetic optimization algorithms and surrogate meta-models are adopted for the multi-objective optimization process in order to obtain the Pareto front (Halouani et al 2012b).…”