动态冲击下纯铝中微损伤演化的仿真研究

文章利用二维程序LS-DYNA模拟计算了不同冲击加载应力下微孔洞的演化过程。模拟结果表明,低速冲击加载下,初始孔洞首先在冲击波的作用下逐渐被压缩,直到完全闭合,接着孔洞在反射稀疏波产生的拉伸应力作用下,又逐渐呈近似圆形长大,由于剪切应变的影响,孔洞长大的形状随时间发生变化。在高速冲击加载下,材料中的孔洞在压缩闭合的过程中会出现孔洞塌陷的现象。文中还给出了受冲击加载后孔洞大小的变化曲线,这些现象和结果目前在实验中很难测量到,这些结果对研究含孔材料在动态冲击下的损伤破坏有一定的帮助。

Simulation of Micro Void Evolution in the Pure Aluminum under Dynamic Loading

The dynamic evolution of micro void under different loading conditions was calculated by use of two-dimensional program LS-DYNA. The Result shows, under low impact velocity, the initial void is first compressed by the shock wave, and nearly closes. After that, the void grows bigger and bigger under the effect of tension stress due to reflection wave. The void nearly keeps a circular shape during the growth, but the shape will change with time because of the shear strain. Under higher impact velocity, the collapse of the void will occur during the process of void closing. The change curve of void after shocked by the flyer is also plotted. It is hard to observe these appearing and resulting in the experiment. The results are helpful to study the fracture of the material with voids under dynamic loading.