Crashworthiness Design Of Vehicle Body Based On Unified Model Under Multiple Load Cases

Crashworthiness research is an important content for vehicle passive safetyresearch and to conduct crashworthiness design body under multiple load cases meetsthe need of practical engineering design. Taking two front load cases for example, thevehicle body structure crashworthiness optimization design was carried out bycomprehensively considering the safety of100%frontal impact and40%offset impact.The defects of discussing only one front impact case at one time were overcome andthe vehicle’s comprehensive safety was improved. The method presented in this paperprovides an idea for vehicle crashworthiness design body under multiple load cases.To conduct the crashworthiness design under multiple load cases, taking apassenger car for example, the finite element models of100%frontal impact and40%offset impact were built. It is proved that a correlation existed between100%frontalimpact and40%offset impact after a preliminary optimization design of100%frontalimpact. Therefore, discussing only one type of impact case at one time was flawed.Considering the100%and40%offset frontal impact crash safetycomprehensively, the crashworthiness optimization of the unified impact model wasconducted. Firstly, five design variables which had a significant effect on the two loadcases were selected through non-repetition saturated factorial design. Then,multi-objective optimization was applied to the two surrogate models and the optimalsolution set was achieved by employing non-dominated sorting genetic algorithm forthe solution. Finally, before and after optimization results show that: the total mass ofthe design variables remained constant; in the100%frontal impact, the B pillar peakacceleration decreased by13.35%while the total energy increased; in the40%offsetfrontal impact, the B pillar peak acceleration decreased by10.43%while the A-pillarshift reduced by18.94%. Each crashworthiness optimization objective has improvedto some extent and the crashworthiness under the two load cases is enhanced.The crashworthiness optimization design of vehicle body structure aimed at100%frontal impact and40%offset impact proposed in this paper has a certainengineering significance. It provides a reference of structure design under the twoload cases.