爆炸载荷作用下相向裂纹扩展行为的实验研究

Experimental study on opposite cracks propagation behavior under blast loading

采用数字激光动态焦散线实验系统,研究爆炸载荷作用下两相向扩展裂纹的动态特征及其相互作用关系。结果表明:相向运动裂纹的扩展过程分为3个阶段:独立扩展、相互排斥、相互吸引,最终形成彼此勾连的形态,在实验范围内不受两裂纹初始竖向距离的影响而改变;裂纹在扩展过程中发生相互作用时其扩展速度发生突跃,此时两裂纹尖端的水平距离随裂纹初始竖向间距的增大而减小;随着两裂纹初始竖向间距的改变,两裂纹开始相互作用时其裂尖距都在56~70 mm之间;两裂纹竖向偏移距离最大位置对应于裂纹尖端水平距离为0的时刻,两相向运动裂纹初始间距越大,裂尖在竖向方向的偏移距离越小。

Adopting digital laser dynamic caustics experimental system,research two mutually to expand crack dynamic characteristics and interaction relations under explosion loading.The results showed that：process relative to the propagation of the crack can be divided into three stages：independent extension,repel each other,attract each other,eventually forming connections to form each other,this feature is not change with the crack initial vertical distance under this experimental condition;Crack propagation speed increase sudden when the crack interact in the process of the extension of crack,and the two horizontal distance of the crack tip decreases with the increase of crack initial vertical distance when the crack propagation speed increase;With the change of the two crack initial vertical distance,the two cracks begin interaction when the crack tip on the between 56-70 mm;The largest vertical migration distance of crack position corresponding to the crack tip horizontal distance of zero moment,resulting from relative movement between two initial crack spacing in the vertical direction of the greater the offset distance,the smaller instead.