爆炸应力波作用下缺陷介质裂纹扩展的动态分析

采用透射式焦散线测试系统，进行爆炸应力波作用下缺陷介质裂纹扩展试验，研究了含与炮孔共线的预制裂隙介质裂纹扩展速度、加速度、裂纹尖端动态应力强度因子和动态能量释放率的变化规律以及它们之间的变化关系。试验结果表明，在爆炸应力波作用下裂隙两端产生了两条翼裂纹A、B，翼裂纹A的长度较翼裂纹B长，两条翼裂纹向相反的方向扩展；在翼裂纹扩展过程中，存在着加速与减速的过程，扩展速度瞬间达到峰值，其后逐渐振荡下降；动态应力强度因子也呈现瞬间达最大值到逐渐减小连续振荡变化的趋势，动态应力强度因子 > ；翼裂纹尖端的动态能量释放率对裂纹扩展具有驱动作用。

Dynamic analysis of crack propagation in media containing flaws under the explosive stress wave

Using transmission caustics system, the crack propagation experiment of media containing prefabricated flaws under explosive stress wave is carried out. The varieties of dynamic stress intensity factor, crack extensions rate, crack extensions acceleration, and dynamic energy release rate in the crack tip of media containing flaw which is collinear with the borehole are studied. The relationship of them is analyzed. Experimental results show that two wing cracks appear at both ends of the flaw in media subjected to blasting loading. The wing crack A length is longer than wing crack B length. Tow wing cracks expand along reverse direction and are co-linear with prefabricated flaw. The cracking velocity and acceleration oscillated with the increase of crack propagating time. The dynamic stress intensity factor value reaches the maximum in a moment and then gradually decreases. The changes of dynamic stress intensity factor also presents oscillation in whole time. At the end, dynamic energy release rate drives crack extension.