Low velocity impact behavior of bioinspired hierarchical armor with filling layer

Some biological carapaces in the natural world have distinctive structures and excellent performance in impact resistance and light weight, which can be used to compensate for the shortcomings of traditional protective equipment in terms of wearing flexibility and energy absorption. A bioinspired hierarchical armor is designed in this article based on the inspiration provided by the internal filling layer of the biological carapace. The outer layer of the armor is made of ultra-high molecular weight polyethylene as the hard front plate, while the soft layer is made of silicone rubber filled with viscous fluid. Impact responses of the fluid filled armors with different soft layers are studied under low velocity impact load. The resistance behavior of the armor with multicell filling layer is analyzed stage by stage using experimental data and images obtained by the high speed camera. The research has found that the armor's synergistic effect of the hard layer, the soft layer and the substrate allows it to absorb enough impact energy and decrease blunt injuries while keeping a certain degree of flexibility in wearing. Furthermore, the fluid filled in the soft layer improves the defect of local excessive intrusion in the previous bioinspired protection studies. The study can provide a reference for the design of new protective equipment.