Lightweight design of automotive composite bumper system using modified particle swarm optimizer

Considering the crashworthiness and lightweight requirements in automotive industry, composite materials have been gaining increasingly more attention for their high specific strength, high specific stiffness and high energy absorption capability. Bumper system is one of the main structures which protect cars from the front and rear collisions. It is an effective way to develop the bumper system using composite materials to meet the crash safety and lightweight demands simultaneously. However, the application of composite material also introduces great challenges into the optimization design process, such as complex non-linear material behavior, multi-working conditions and large amount of design variables. In this paper, a structure design and optimization method is proposed for a commercial front bumper system made by carbon fiber woven composite. An integrated bumper system structure is presented considering the manufacturing process of composite material. Then, an optimization procedure incorporating the Kriging modeling technique and a modified PSO algorithm is proposed to find the optimal combination of design variables. The real vehicle experiment proves that the optimized bumper system meets all the requirements on strength and crashworthiness while with 31.5% weight reduction. The results reveal that the proposed design method is an efficient and effective way for composite structure design.