摘要
利用显式动力有限元ANSYS/LS-DYNA数值研究了六韧带手性蜂窝结构的面内冲击动力学特性。在保证圆环节点半径不变的前提下,通过改变韧带长度和胞元厚度,首先建立了六韧带手性蜂窝的有限元模型,具体讨论了冲击速度和胞元微结构参数对手性蜂窝材料的面内宏/微观变形行为、密实应变、动态平台应力和比能量吸收能力的影响。研究结果表明,随着冲击速度的增加,六韧带手性蜂窝结构表现为3种宏观变形模态:"><"型模式、"过渡"模式和"I"型模式。在中、低速冲击载荷下,能够明显观察到拉胀材料在轴向压缩时独特的"颈缩"现象,其主要与韧带绕着圆环中心节点的旋转变形有关。通过引入无量纲"动态敏感因子",还研究了六韧带手性蜂窝材料的面内动态冲击强化效应。
The in-plane dynamic crushing behaviors of hexagonal chiral （hexachiral） honeycombs were numerically studied by explicit dynamic finite element （EDFE） simulations using ANSYS/LS-DYNA. Assuming that the circular radii are all the same, the FE models of hexachiral honeycombs were first established by the variation of ligament length and cell-wall thickness. The respective influences of the impact velocity and microcell structural parameters on the in-plane macro-/micro-deformation behaviors, densification strains, dynamic plateau stresses and specific energy absorption of chiral honeycombs were discussed. Numerical results show three different types of deformation modes for hexachiral honeycombs with increasing impact velocity： ＂ 〉 〈 ＂ mode, ＂transition＂ mode, and ＂I＂ mode. Under low or moderate velocity crushing, hexachiral honeycombs display a particular lateral compression ＂shrinkage＂ phenomenon of auxetic materials, which mainly depends on the rotation deformation of the ligament on the central node. By introducing a nondimensional ＂dynamic sensitivity index＂, the in-plane dynamic enhancement effect of hexachiral honeycombs was also investigated.
出处
《振动与冲击》
EI
CSCD
北大核心
2016年第8期1-7,26,共8页
Journal of Vibration and Shock
基金
国家自然科学基金资助项目(11402089)
河北省自然科学基金资助项目(A2013502120)
中央高校基本科研业务费专项资金资助项目(2014MS117)
关键词
六韧带手性蜂窝
平台应力
变形模式
动态强化
负泊松比
hexachiral honeycomb
plateau stress
deformation modes
dynamic enhancement
negative Poisson＇sratio （NPR）
