多胞金属在中低速冲击下的防护应力

文中通过理论和数值模拟研究了多胞金属在中低速冲击下的防护应力,发现防护应力在冲击过程中出现周期性卸载,这是由于弹性波在支撑端的反射所致. 结果发现与高速冲击情况不同,在中低速冲击下,蜂窝的平均防护应力会随着冲击速度的减小而增大;该现象可以用微结构的惯性效应来解释,此时若采用蜂窝的塑性坍塌应力将高估其防护应力. 最后给出了金属蜂窝在中低速冲击下防护应力的表达式,与数值计算结果吻合良好.

Protective Stress of Cellular Metals Under the Low and Medium Velocity Impact

In this paper, the protective stress of honeycombs under the low and medium velocity crushing was theoretical analyzed and numerically simulated. It is found that the protective stress was periodically unloaded during the crushing process due to the reflection of the elastic wave at the supporting end. The results show that unlike the cases of the high-velocity impact, the average protective stress under the low and medium velocity crushing of the honeycombs increases with the reduction in the impact velocity. This phenomenon can be explained by the inertia effect of the micro-structures. Simply adopting the plastic collapse strength will over-evaluate the protective stress of the honeycomb under the low and medium velocity crushing. A new expression was derived to evaluate the protective stress and exhibits a good agreement with the numerical simulations.