Abstract: The power assembly acceleration, the maximum car-body acceleration and power acceleration stiffness are the most important factors in vehicle passive safety. Therefore, in concept auto design these factors must be considered. In this paper a layout optimization method of the key parts of simplified model of concept auto, equivalent to a mass-spring system, is proposed. In the system, the forces among the parts are transformed to spring stiffness broken lines, and relative positions of the key parts are described by the relative maximum displacements, which are taken as the parameters in the optimization. Multi-objective optimization is applied in the concept car layout, and the objectives are the acceleration and so on. The overall optimal lay out of the vehicle structure is obtained by parameter iteration. The feasibility of the proposed optimization method is proved by simulation of a concept vehicle lay out example.

Key words: vehicle engineering, automobile collision, key point, multi-objectives optimization method, passive safety, mechanical vibration method