非均质焊接接头的裂纹尖端拘束与J积分应用的可行性

CRACK TIP CONSTRAINT AND APPLICATION FEASIBILITY OF J INTEGRAL IN HETEROGENEOUS WELDED JOINTS

采用弹塑性大变形有限元方法，分析了平面应力状态下非均质焊接接头中以应力三轴度表征的裂纹尖端拘束．结果表明，接头中裂纹尖端拘束不能满足ＨＲＲ场要求而显示出与接头匹配、裂纹长度和裂纹模型有关的复杂演化规律．因此。

Crack tip constraint characterized by stress triaxiality for heterogeneous welded joints in a plane stress case is investigated in this paper by the elastic plastic finite deformation finite element method. The results show that the crack tip constraint in welded joints cannot satisfy the requirements of the HRR field but reveals the complicated evolution laws associated with weldmatching, crack size and crack model. Therefore, it is deubtful whether J integral can be directly used as a fracture parameter in welded joints.