INVESTIGATION ON CRUSHING BEHAVIOR OF METAL HONEYCOMB-LIKE HIERARCHICAL STRUCTURES

Crushing behavior of metal honeycomb-like hierarchical structures of perforations on single walls (HHSPSW) and double walls (HHSPDW) was systematically investigated by using experiment and numerical simulation methods. Effects of specimen size, perforation location, perforation offsets and perforation gradient on the mechanical properties of honeycomb-like hierarchical structures were analyzed. The results show that the crushing process of honeycomb-like hierarchical structures can be divided into three deformation stages: elastic deformation, buckling deformation and densification. The deformation mode of honeycomb-like hierarchical structures of perforations on single walls is a progressive concave mode, while honeycomb-like hierarchical structures of perforations on double walls deform by axial crushing mode. Specimen sizes have significant influences on mechanical behavior of honeycomb-like hierarchical structures. Mechanical properties are almost independent of honeycomb numbers attaining a certain number. The peak stress of the honeycomb-like hierarchical structures of perforations on single walls is greater than that of honeycomb-like hierarchical structures of perforations on double walls, while its mean crushing stress is less than that of honeycomb-like hierarchical structures of perforations on double walls. Comparing to the traditional honeycombs, the design of perforations on honeycomb walls reduces the specific energy absorption of the honeycombs. Perforation offsets result in decreasing the peak stress of the honeycomb-like hierarchical structures of perforations on single walls, while the mean crushing stress firstly decreases and then increases with increasing the perforation offset. Honeycomb-like hierarchical structures with positive gradient perforations reduce the peak stresses while improve the mean crushing stress comparing to honeycomb-like hierarchical structures with the uniform perforations. The design of muti-gradient perforation distributions on honeycomb walls has small influence on the peak stress and the mean crushing stress.