不同倾角预制裂纹缺陷与运动裂纹的相互作用

为了研究运动裂纹与不同倾角预制裂纹缺陷之间的作用机制，采用数字激光动态焦散线方法对含不同倾角预制裂纹缺陷的三点弯曲梁进行冲击实验。研究结果表明，在冲击载荷作用下，预制裂纹缺陷尖端均产生了次生裂纹；当运动主裂纹与预制裂纹缺陷贯通时，次生裂纹不会立即起裂，而是经过0~10 μs的能量积蓄后，次生裂纹才起裂；运动主裂纹应力强度因子峰值与次裂纹起裂时的应力强度因子值均随预制裂纹倾角的增大而增大。

Interaction between a pre-existing crack defect with different angles and a running crack

Using the digital-laser dynamic caustic system, the impact tests of the three-point bending beam were performed to investigate the interaction mechanism between a pre-existing crack defect with different angles and a running crack. The experimental results show that the secondary cracks were initiated at the tips of the middle pre-existing cracks under impact loading; the secondary cracks at the tip of the pre-existing cracks would not initiate until they have accumulated more energy in 0-10 μs; both the peak value of the dynamic stress intensity factor of the main cracks and the secondary cracks would rise with the increase of the pre-existing cracks angle in the central part of the specimen.