Optimized design of car frontal bumper with aluminum foam sandwich structure under low velocity impacts

Abstract

This study introduces a novel sandwich structure absorber for car bumpers, utilizing thin layers of aluminium foam. This absorber improves energy absorption and impact resistance. This research compares the novel absorber to a conventional polymer-integrated model, by examining impact force, von-Mises stress, equivalent plastic strain, energy absorption, and coefficient of restitution. Utilizing the finite element method, the effects of shell density and thickness are analysed under E.C.E-R042 low-velocity impact standards. Sandwich absorbers exhibit lower stresses and plastic strains in the core. In addition, they demonstrate smaller impact forces and enhanced energy absorption within a specific range of shell densities. Furthermore, the absorber’s flexibility strongly influences contact time. The core of sandwich absorber models accounts for between 70 and 90% of energy absorption, indicating slightly lower energy absorption than polymer foams. The simulation results are analysed using analysis of variance to investigate the combined effect of the density and thickness of the sandwich absorber shell on the efficiency of the sandwich absorber. The optimal values of density and thickness are determined using grey relation analysis to be 150 kg/m³ and 25 mm, respectively.