Shape optimization of bumper beams under high-velocity impact loads

Abstract

Box-shaped bumper beams mounted on vehicles serve as shock absorbers in a potential crash. In this study, their optimal shape design is investigated. The objective is to maximize the crashworthiness of the beam. The crash phenomenon in standard tests is simulated in which the vehicle hits a deformable barrier with 40% offset by 64km/h speed. The bumper beam and the brackets supporting the beam are modeled as deformable bodies in full detail. For the rest of the car, a lumped parameter model is developed. The crash event is simulated using explicit finite element method. The design variables are the parameters defining the cross-sectional shape of the beam. The beam is optimized using a hybrid search algorithm combining Genetic and Nelder & Mead algorithms. The results indicate significant improvement in the crashworthiness of the bumper beam currently in-use. Resistance to low-velocity impact is also improved.