Theoretical and numerical investigation on in-plane impact performance of chiral honeycomb core structure

Honeycomb materials have been widely used as energy absorbers in structural impact protection and it can be tailored to shrink in the vicinity of impact zone, which contributes to better impact resistance. The chiral honeycomb is characterized by a non-intuitive negative in-plane Poisson's ratio (auxeticity), for the hexagonal chiral honeycomb, which exhibits a theoretic value of -1. However, the comprehensive study of the performance of chiral honeycomb under impact has not been studied to date. In this paper, firstly, the theoretical solution of yield stress for chiral honeycomb was obtained in terms of quasi-static loading. Thereafter, the in-plane dynamic crushing and energy-absorption capabilities of chiral honeycomb were studied numerically by means of finite element (FE) method. A comparative study between the chiral honeycomb and conventional hexagonal honeycomb was also performed to identify the advantages and disadvantages of the two materials. In addition, a parametric study was conducted to investigate the effects of geometric topologies and impact scenarios on the response of chiral honeycomb. The numerical results show that the performance of plastic energy dissipation of chiral honeycomb is dependent not only on structural parameters but also on crushing velocities. The present study is committed to providing an important reference to the application of chiral honeycomb in the crashworthiness design.