Abstract: Automotive structural optimization related to crashworthiness and energy absorption capability is a process of optimization which involves multi-variable, multi-constraint and multi-objective. To solve the problem of low precision of conventional response surface method caused by the approaching in the whole design space and the problem of traditional single-objective optimization design as it can only optimize one objective， a successive approximation method is proposed. Through moving and zooming, the region of interest is constantly renewed in the design space. In the different regions of interest, the experimental design, a high-precision approximation model that can represent the actual collision process, and multi-objective particle swarm optimization algorithm are combined, then a set of minimized non-inferior solutions for objective functions are obtained. By using the minimum distance solution selection method, a set of solutions with best crashworthiness effect are rapidly and effectively selected from the set of non-inferior solutions, and taken as the center of region of interest of next iterative step until converging to the best solution, then all the objective functions of the final solution are improved. Numerical example indicates that this method has high precision and strong engineering practicability.

Key words: Crashworthiness simulation, Multi-objective, Optimization design, Particle swarm optimization