Experiment and Optimization of Stepwise Graded Foam for Enhanced High Overload Shedding Property

Herein, to achieve the large deformation of metallic foams at high strain rate, an improved split Hopkinson pressure bar (SHPB) technique is developed. Using this improved SHPB technique, the dynamic properties of three kinds of single metallic foams and a stepwise graded foam are measured. Their energy absorption capacities are analyzed. Finite element simulation of SHPB test on the stepwise graded foam is carried out, and excellent agreement between the simulated result and experimental result is obtained. Then, the high overload shedding properties of the single foams and stepwise graded foam are analyzed via finite element simulations of SHPB tests. The results present that the stepwise graded foam possesses superior high overload shedding property than the single metallic foams, and the decreased percentage of the maximum acceleration for the stepwise graded foam is about 77.9%. To further improve the high overload shedding properties of the stepwise graded foam, multiobjective structural optimization is conducted. The decreased percentage of the maximum acceleration for the optimized stepwise graded foam is about 90.8%, indicating the remarkable high overload shedding property. These results of this study suggest the promising prospects of the stepwise graded foam for high overload shedding.