基于旋转三角形模型的负泊松比蜂窝材料面内动态压溃行为数值模拟

摘要

为提升蜂窝材料的动态力学性能,在旋转三角形变形构型基础上,针对不同旋转角建立了对应的蜂窝结构模型.利用这些蜂窝模型通过有限元分析软件ANSYS/LS-DYNA数值模拟了不同旋转角的蜂窝在冲击载荷作用下的面内动态压溃行为;同时考虑冲击速度的影响,研究了旋转角和冲击速度对其变形模式以及平台应力的影响规律,并对比分析了旋转三角形蜂窝的吸能特性.结果表明:旋转三角形蜂窝的变形过程一般可分为旋转变形和坍塌变形两个阶段,其应力-应变曲线具有“两段式应力平台”特征,且表现出明显的动态拉胀效应;当旋转角增大或冲击速度提高到某个临界值后,其应力-应变曲线只具有一个平台段,动态拉胀效应逐渐减弱;在不同冲击速度下,通过与相对密度相同的正六边形蜂窝相比较,旋转三角形蜂窝具有更好的能量吸收能力.%On the basis of rotating triangle model,the different honeycomb models for different rotating angles are presented to improve the dynamic mechanical properties of honeycomb material.Numerical simulations by software ANSYS/LS-DYNA were conducted to explore the in-plane dynamic crushing behavior of the rotating triangle honeycombs at different impact velocities.The effects of rotating angles and impact velocities on deformation modes and the plateau stress are investigated,and the energy absorption characteristics of rotating triangle honeycombs are discussed.The results show that the deformation process of rotating triangle honeycombs is divided into two phases,and the nominal stress-strain curve has two plateau regions.The rotating triangle honeycombs have certain dynamic auxetic characteristics.When the rotating angle or the impact velocity reaches to a critical value,the nominal stress-strain curve has only one plateau region.At different impact velocities,the rotating triangle honeycombs have better energy absorption capacity compared to the hexagonal honeycombs.