Design and optimization of the bumper beam with corrugated core structure of fiber metal laminate subjected to low-velocity impact

Fiber metal laminates (FMLs) exhibit good impact resistance performance with hybrid structures based on alternating stacking of metal alloy layers and fiber-reinforced composite plies. Therefore, FMLs become excellent candidates for bumper beams in automobiles with an enhanced energy absorption capacity. Herein, the design and optimization of the bumper beam consisted of FMLs corrugated sandwich structure subjected to low-velocity impact were investigated. Firstly, material characteristic parameters of aluminum alloy and carbon fiber reinforced thermoset polymer (CFRP) were obtained from the quasi-static and dynamic experiments respectively. Then, finite element analysis (FEA) of cap structures of FMLs was established to capture the deformation process of the low-velocity impact. The simulation results were well-validated using material parameters from the dynamic mechanical tests. Afterward, the influence of material type and stacking sequences on performance was numerically investigated under low-velocity impact loading, whereas the performance of aluminum alloy and CFRP were set as controls. A multi-objective optimization method was considered to realize the maximum energy absorption with minimum impact peak force. The non-dominated sorting genetic algorithm II (NSGA-II) was introduced to obtain the global optimum solution. The current work highlights the excellent mechanical performance of the FMLs bumper beam in low-velocity impact.