随机缺陷对蜂窝结构动态行为影响的有限元分析

摘要

Finite element simulations are performed to study the effect of randomly removing cell walls on the dynamic crushing behaviour of honeycomb structures. The influences of the imperfection and impact velocity on the deformation mode and plateau stress axe investigated. Simulation results reveal that both imperfection and impact velocity affect the deformation modes as well as the critical velocities of mode transition. It is found that the plateau stress is proportional to the square of the impact velocity when the imperfect honeycombs are deformed at transitional mode or dynamic mode. When the impact velocity is near the critical velocity between transitional mode and dynamic mode, honeycombs with small fraction of imperfection exhibit higher plateau stress, comparing to those of regular honeycombs having the same relative density. However, when the imperfection further increases, the plateau stress decreases obviously near the critical velocity between quasi-static mode and transitional mode.%通过对胞壁随机移除的蜂窝结构动态变形过程的有限元模拟,分析了随机缺陷对蜂窝结构变形模式的影响,得到蜂窝结构在两个加载方向上的变形模式图及不同模式间转换的临界速度.对含缺陷蜂窝结构平台应力的研究发现,当变形模式为过渡模式或动态模式时结构平台应力与冲击速度的平方成线性关系.相同密度下,低缺陷蜂窝结构的平台应力在由过渡模式向动态模式转变的临界速度附近高于规则蜂窝结构,较高的随机缺陷则使蜂窝结构的平台应力在由准静态模式向过渡模式转变的临界速度附近显著下降.