In-plane Dynamic Crushing of a Novel Bio-inspired Re-entrant Honeycomb With Negative Poisson's Ratio

In order to seek higher crashworthiness and energy absorption capacity, based on biological inspiration, a novel bio-inspired re-entrant honeycomb (BRH) structure with negative Poisson's ratio is designed by selecting lotus leaf vein as biological prototype. The numerical simulation model is established by the nonlinear dynamics software ABAQUS and further compared with the available reference results to verify the feasibility. The dynamic compression behavior and energy absorption capacity of two types of BRH (BRH-I and BRH-II) are firstly compared with conventional re-entrant honeycomb (RH). The simulation results show that BRH has better mechanical properties and energy absorption characteristics. Then, the crushing behavior of BRH-II under different impact velocities is systematically studied. Three typical deformation modes of BRH-II are observed through the analysis of deformation profile. The quasi-static plateau stress is closely related to the cellular structure. Based on one-dimensional shock theory, the empirical equations of dynamic plateau stress for BRH-II with different relative densities are given by using least square fitting. In addition, the effects of impact velocity and relative density on plateau stress and energy absorption behavior are also studied. The results show that the energy absorption capacity of BRH-II is increased nearly six times compared with RH at the same impact velocity.