内凹-反手性蜂窝结构的面内动态压溃性能研究

通过内凹六边形蜂窝与反手性蜂窝的结合得到一种内凹-反手性蜂窝(re-entrant anti-trichiral honeycomb,RATH)结构。利用显式动力有限元软件LS-DYNA对不同冲击速度和不同相对密度下内凹-反手性蜂窝的变形模式、抗冲击性能及拉胀性能进行了研究。结果表明,引入内凹结构可以显著增强中低速冲击时反手性蜂窝的局部“颈缩”现象,且在靠近内凹-反手性蜂窝的冲击端呈现出明显的“V形”变形带。与三边反手性蜂窝及传统蜂窝相比,内凹-反手性蜂窝的能量吸收性能更强,负泊松比效应更明显。基于一维冲击波理论,推导了内凹-反手性蜂窝的临界冲击速度和平台应力的经验公式。此外,讨论了冲击速度和胞壁厚度对平台应力及平台应变的影响。该研究将为混合变形机制拉胀蜂窝结构的设计提供新的思路。

In-plane dynamic crushing characteristics of re-entrant anti-trichiral honeycomb

A re-entrant anti-trichiral honeycomb(RATH)was designed by combining the re-entrant honeycomb and the anti-chiral honeycomb(ATH).The deformation modes,impact resistance,and auxetic performances of RATH with different impact velocities and relative densities were studied by using the dynamic explicit simulation software LS-DYNA.The results show that introducing the re-entrant structure can enhance the localized“necking”phenomenon of ATH under medium-and low-velocity impact and that a V-shaped deformation band appears near the impact end of RATH.Compared with the ATH and conventional honeycomb,the RATH has better energy absorption capacity and negative Poisson’s ratio effect.The empirical formulas for critical impact velocity and plateau stress were deduced based on the 1D shock theory and numerical simulation.In addition,the effects of the cell-wall thicknesses and crushing velocity on the plateau stress and plateau strain were systematically explored.This study is expected to provide a novel path for design of auxetic honeycombs with hybrid deformation mechanism.