A Multi-material Lightweight Design Based On Crashworthiness Of Vehicle

Proceed from the reality in engineering, a multi-material lightweightoptimization with the regard of crashworthiness of frontal-impact and side-impact ispresented in this paper. Proper type of lightweight material were applied to thevehicle and the optimization design also took the cost of material into considerationwhile lighten the weight. It provides some reference to the lightweight andcrashworthiness design of vehicle.Targeted at cost effectiveness and light weight, an optimization of forepart of avehicle model was conducted. Firstly, five components which were crucial to frontalimpact safety were selected through factorial design. Then, the multi-objectiveoptimization model concerning mass and cost was established after reselectingmaterial type for those components and utilizing ultra high strength steel andaluminum alloy for the design. Finally, by employing quadratic response surfaceapproximation models and multi-island genetic algorithm, the Pareto optimal solutionset was achieved. The results show that the weight of the five components is reducedand the cost is also diminished, while the frontal impact safety remains the same.Another lightweight optimization was conducted without any loss of side impactsafety. Firstly, six side panel components that contributed most to side impact safetywere selected through global sensitivity analysis. Then, high-strength steel, hotforming steel and aluminum were applied to the six components’ lightweight design.According to the evaluation criteria of the American IIHS, the distance from the seatcenterline at the pelvis (at the height of300mm from the floor) and thorax (at theheight of600mm from the floor) of the diver were taken as side-impact safetyevaluation criteria. Finally, the optimization model targeted at lightweight and costeffectiveness was established. The multi-objective optimization problem was solvedthrough approximate model technologies and NSGA-Ⅱ algorithm.Mergedmulti-material design concept, the optimization design methods proposed in this paperresort to practical situation in engineering cases and provide a reference to thelightweight design of vehicle body.