Sequential coupled process-performance simulation and multi-objective optimization of thin-walled tubes

A sequential coupled nonlinear finite element analysis framework is developed to investigate the effects of sheet-forming process and product design parameters on energy absorption characteristics of thin-walled, multicorner tubes made of a magnesium alloy. Coupling stems from the use of analysis results from one simulation to form the initial state in the subsequent simulation. High fidelity coupled process-performance simulations are used in design of computer experiments for developing analytical surrogate models of process and performance responses as functions of product geometry and process parameters. Rupture, thinning and springback are treated as the manufacturing responses whereas mean crush force, maximum crush force, and mass are used as structural performance measures. An integrated process-performance optimization problem is setup and solved using the multi-objective genetic algorithm approach. The results of coupled simulations show the importance of manufacturing effects on the crush response while the Pareto optimal set highlights the tradeoff among process and performance attributes.