多胞材料的动态应力应变状态及其一致近似关系

多胞材料在高速冲击下呈现出逐层压溃的变形模式，塑性冲击波模型可以用来表征这种集中变形带的传播行为。本文中采用截面应力计算方法得到了随机蜂窝在恒速冲击下的一维应力分布，进而对冲击波的传播规律进行了分析。比较了高速冲击下由不同方法得到的冲击波速度与冲击速度的关系，结果表明R-PP-L（率无关，刚性-理想塑性-锁定）模型高估了冲击波速度，但R-PH（率无关，刚性-塑性硬化）模型以及一维冲击波理论得到的冲击波速度与有限元结果比较接近。冲击波速度与冲击速度在高速情形下趋于线性关系，但随着冲击速度的减小，冲击波速度不断减少并趋于常数。根据这一特征和塑性冲击波模型，发展了可以表征冲击波速度与冲击速度的关系、动态应力应变关系的一致近似模型。

Dynamic stress-strain states of cellular materials and a uniformly approximated relation

Cellular material under high-speed impact is deformed in a mode of layer-wise propagation of crushing bands, which can be characterized by the plastic shock models. In this paper, we obtained the one-dimensional stress distribution of a random honeycomb under constant-velocity compression using the cross-sectional stress calculation method, analyzed the shockwave propagation, and examined the relation between the shockwave velocity and the impact velocity obtained by different methods under high-velocity impact. The results show that the shockwave speed is overestimated by the R-PP-L (rate-independent, rigid-perfect plastic-locking) model, but the shockwave speeds obtained by the R-PH (rate-independent, rigid-plastic hardening) model and the one-dimensional shock theory are close to that of finite element simulation. The relation between the shockwave velocity and the impact velocity tends to be linear at high impact velocities, and the shockwave speed reduces to a constant with the decrease of the impact velocity. In light of these characteristics and based on the plastic shockwave model, we developed a uniformly approximated model is developed to characterize the relation between the shockwave velocity and the impact velocity and the dynamic stress-strain relation of cellular material.