Optimization of contact forces in tailor-welded blanks forming process

Abstract

To attain the objective of minimizing the harmful movement of the weld joint in tailor-welded blanks (TWBs) forming, a novel optimization methodology based on dynamic explicit finite element simulation is presented to determine optimum contact forces. In this methodology, forming limit diagram (FLD) models developed for different types of TWBs are treated as a criterion of constraint in optimizations. Due to the highly nonlinear nature of the forming process, response surface methodology (RSM) is utilized to construct sequential response surfaces to approximately describe the objective the constraint functions and the optimum contact forces of TWBs stamping are obtained with some successive iterations. However, a large number of numerical simulation runs are needed for optimization with higher-order approximate models or many design variables. To improve the efficiency of optimization, the space mapping (SM) technique utilizing surrogate models is integrated with RSM. Two examples are used to validate this algorithm: one optimization for TWBs stamping with the same thickness but different materials, and the other optimization for TWBs stamping with the same material but different thicknesses. The results demonstrate that the method is efficient and effective in solving contact forces optimization problems.