In-plane energy absorption characteristics and mechanical properties of novel re-entrant honeycombs

This paper proposes novel re-entrant honeycombs (NREH), which are designed as the support ribs of the re-entrant honeycomb subunit in an asymmetrical form to further improve its mechanical properties. First, three types of NREH composed of asymmetric subunits are compared. The σm and specific energy absorption (SEA) of the three NREHs are not much different during in-plane impact, while the Poisson's ratio of NREH-3 is smaller than that of the other NREHs. Analyze the performance of NREH-3 by analyzing the change of angle θ. It was found that in the y-direction, the SEA of NREH-3-80 is 41.46% higher than that of NREH-3-60, and the Poisson's ratio is almost unchanged. On x-direction, the energy absorption performance is not significantly improved. Analysis of NREH-3′s sensitivity to impact velocity revealed that NREH-3-60, NREH-3-70, and NREH-3-80 are greatly affected by impact velocity. As the velocity increases, their deformation models significantly change, while other structures remain constant. An analysis of the influence of NREH-3 on wall thickness showed that the SEA of NREH-3 is significantly improved with increasing wall thickness and that Poisson's ratio did not significantly change, indicating that appropriately increasing the wall thickness effectively improves the impact resistance of the honeycomb structure.