空孔缺陷与邻近运动裂纹的相互作用初探

运用落锤冲击加载方式,实现对试件的动态加载,研究了空孔缺陷对临近运动裂纹扩展形态的影响,分析了运动裂纹扩展过程中的动态应力强度因子和速度的变化趋势。结果表明:空孔缺陷对临近运动裂纹具有"吸引"效应,并且这种"吸引"效应的强度随着空孔缺陷与邻近运动裂纹距离的增大而减弱。此外,空孔缺陷对临近运动裂纹的扩展具有明显的抑制作用。运动裂纹在空孔缺陷处的再次起裂更为困难,需要更多的时间积蓄能量。实验结果为后续深入研究运动裂纹与材料缺陷的相互作用提供了实验思路。

Initial exploration on interaction between empty hole flaw and adjacent running crack

Adopting the impact loading method of drop hammer to apply dynamic loading on the specimen, effects of empty hole flaw on propagation forms of adjacent running crack are studied, changing trends of dynamic stress intensity factor and velocity of running crack during propagation are analyzed. The results show that the empty hole flaw has an attracting effect on adjacent running crack, and degree of the attracting effect decreases with increasing of the distance between the empty hole flaw and the running crack. In addition, the empty hole flaw suppresses the propagation of adjacent running crack obviously. Initiation of the running crack at the empty hole flaw is more difficult and needs more time to accumulate energy. The experimental results provide experimental consideration for deeper research on interaction between running crack and material flaw.