用高速阴影技术研究K9玻璃中的失效波

Investigations of Failure Waves in K9 Glass Using Shadowgraph

用高速阴影摄影技术研究了爆轰加载下K9玻璃样品中波的传播和压缩区内损伤破坏的物理图象和规律。实验中观测到冲击波阵面后有一个移动速度为 2 .1～ 2 .2mm/ μs的黑色阴影区边界 ,即失效波 (Fail urewave) ;实验发现只有当冲击载荷接近材料的HEL时 ,在冲击波和失效波之间的区域才有少量的微裂纹成核和长大 ,而在冲击载荷较低时却没有观察到 ;同时实验中观测到失效波萌生于被撞击面 ,并在两块玻璃的交界面上观测到失效波的再生。这些结果表明失效波的产生基本与冲击相变无关 ,主要与玻璃样品表面的初始损伤有关 ,换言之 ,失效波是玻璃样品表面微裂纹在冲击波作用下失稳扩展造成的。

The high-speed shadowgraph technique was used in visualization of the shock wave moving, damage formation and development in the glass specimen. It is found that failure wave formed at the shocked surface and inner interface, and propagated into specimen following the shock wave . It is concluded that formation of failure wave was connected with the surface of glass-specimen ,and it is a moving fractured front. The work finished here will be helpful to understand the mechanism of failure wave.