泡沫子弹撞击刚性靶板的理论模型

Taylor撞击常用于测试材料的动态屈服强度。泡沫压缩密度与压缩应变的关系对泡沫子弹Taylor撞击的理论分析起着重要的作用。本文通过引入塑性泊松比，得到了泡沫压缩密度与压缩应变的准确关系，进一步建立了可压缩泡沫子弹撞击刚性靶板的理论模型。当塑性泊松比为常数时，文中建立的泡沫受压后密度比的一阶泰勒展开式可以退化到已有模型。当塑性泊松比为塑性应变和子弹相对密度的函数时，相对密度会影响泡沫子弹的冲击响应历程及最终变形，但对撞击持续时间影响较小。同时，初始速度也会影响子弹最终变形和撞击持续时间。本文的理论工作可以为分析泡沫材料的动态力学行为提供有益指导。

Theoretical model for a porous projectile striking on flat rigid anvil

Taylor impact is often applied to the determination of the dynamic yield stress of materials. For theoretical analysis of the Taylor impact of porous projectiles, the relationship between the density of a compressed porous projectile and the compressive plastic strain is very important. This paper proposes an exact density model for the compressible porous projectile by inducing the plastic Poisson's ratio, and further, an analytical model is established for the compressible porous projectile striking on a flat rigid anvil. As the plastic Poisson's ratio is a constant, the first order Taylor series expansion of the compression density ratio model can be reduced to the existing model. As the plastic Poisson's ratio is a function of the compressive plastic strain and the relative density, the relative density has a major influence on the impact response and the final deformation of the projectile, but the duration of impact-contact process is almost unaffected. The initial velocity of the projectile has considerable effects on both the final deformation of the projectile and the duration of impact-contact process. The present theoretical model is useful in analyzing the dynamic behavior of porous materials.