Design Optimization of Vehicle Structures for Crashworthiness Using Equivalent Mechanism Approximations

Passenger vehicle crashworthiness is one of the essential vehicle attributes. According to National Highway Traffic Safety Administration (NHTSA), there were over six million vehicle crashes in the United States in the year 2000, which claimed the lives of more than forty thousand persons. Vehicle crashworthiness is difficult to satisfy in a manner appeasing to other design decisions about the vehicle. This paper aims at developing a novel methodology for crashworthiness optimization of vehicle structures. Based on observations of the manner of structural deformation, the authors propose the abstraction of the actual vehicle structure, which is to be represented as a linkage mechanism having special nonlinear springs at the joints. The special springs are chosen to allow the motion of the mechanism to capture the overall motion of the actual vehicle structure. It thus becomes possible to optimize the mechanism, which is an easier task than directly optimizing the vehicle structure. A realization of the optimized mechanism is then performed to obtain an equivalent structure, and then direct optimization of the realized structure is performed for further tuning. The study presented shows the success of the proposed approach in finding better designs than direct optimization while using comparatively less computational resources.