ABSTRACT
The continuous pursuit of lightweight and highenergy absorption of structures has significantly propelled the applications of honeycomb structures in high-technology industries such as automotive, aerospace and shipbuilding industry. The general energy-absorption mechanism of honeycomb structures under impact loadings is transforming impact energy into plastic deformation energy at the expense of progressive crushing of cell walls in outof-plane direction. In in-plane direction, the energyabsorption mode of crushing honeycomb structures is rowing over each other. Sufficient studies on honeycomb structures can be observed currently and the emphases mainly focus on these aspects of geometric topology (Li et al., 2007, Hu et al., 2015), constituent material (Baker et al., 1998, Aktay et al., 2008) and honeycomb composite (Zhang et al., 2010, Kaman et al., 2010), etc. When it comes to crashworthiness applications, in-plane behaviors of honeycomb structures are relatively understated, because crushing in out-of-plane direction of honeycomb structures is more effective in energy absorption than that happening in in-plane direction. Amongst various kinds of possible existence of geometric topologies of honeycomb materials, there are certain topologies leading to materials with zero, even negative Poisson’s ratio (NPR) in in-plane direction (Grima et al., 2010, Mousanezhad et al., 2015).
