摘要
利用动态几何信息再更新策略,重置预压后胞元的单元信息及边界条件,实现了铝蜂窝预压缩数值模拟。对比准静态实验,分析了预压缩前后蜂窝力学特性的变化。采用数值模拟手段研究了预压缩对峰值力特性在冲击速率与预压深度两方面的敏感性,结果表明:准静态加载时,蜂窝直接进入稳定压缩段,初始峰值力不复存在;动态低速加载时,若预压量低于某定值,蜂窝先进入稳定压缩段,继而出现二次峰值,达到甚至超过该值后,预压后峰值特性趋于稳定,峰值均出现在加载初始时刻,理想的周期性褶皱对应周期性峰值力的现象并不存在;对出现二次峰值的预压蜂窝,二次峰值随冲击速率的提高增加不明显,在速率达到20m/s后,反而在加载初始时刻出现新的初始峰值力,该力值甚至大于二次峰值;总体而言,二次峰值与预压后初始峰值均小于未预压处理的蜂窝初始峰值,峰值特性得到明显改观。系列结果对蜂窝吸能材料选择与设计提供重要参考。
Numerical simulations of the pre-compressed aluminum honeycomb on sensitivity in drop- ping the first peak force were presented by resetting boundary conditions after refreshing the dynamic geometry and cell element information. The mechanical behavior of the aluminum honeycomb was ob- served before and after pre-compression compared with the quasi-static experiment, and necessarily the sensitivity of the first peak force on impact velocity and pre-compressed depth was analyzed. The results show that the honeycomb enters directly into the plateau stage without the first peak force un- der quasi-static loads; while impacting at a low velocity, there is a critical pre-compressed depth, and less than which a second peak force appears after some of stable compression, but when equal or larger than the critical depth, it appears at the initial time, thus, it is not tenable that the ideal periodic fold corresponding with the periodic peak force; to the pre-compressed honeycomb which has a second peak, the growing of the second peak is unobvious with the increasing of the impact velocity, on the contrary, a new initial peak force appears, which is even higher than the second one when the impact velocity higher than 20m/s; in general, both of the second peak force and the initial one are far smal ler than the first peak force of the general honeycomb, and the property of the peak force is improved significantly after pre-compression. Series conclusions provide significant references for choosing and designing of cellular energy-absorbing materials.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2013年第5期78-82,88,共6页
Journal of Materials Engineering
基金
中南大学中央高校基本科研业务费专项资金资助项目(2012zzts015)
湖南省科技计划项目(2011RS4062)
关键词
铝蜂窝
预压缩
初始峰值力
敏感性
aluminum honeycomb
pre-compression
first peak force
sensitivity
