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焊接接头是一个宏观力学不均匀体 ,力学不均匀性对焊接接头的动态断裂行为有重要的影响。采用MARC有限元程序 ,对含焊缝中心裂纹的低匹配焊接接头三点弯曲试样的动态断裂响应进行了计算模拟 ,并采用虚拟裂纹扩展方法计算了动态J积分断裂参量。作为比较 ,计算了相同条件下全母材及全焊缝三点弯曲试样的动态响应。由于惯性效应的作用 ,动态载荷响应曲线周期振动 ,焊接接头试样的动态载荷响应值介于全母材与全焊缝之间。用虚拟裂纹扩展方法计算的动态J积分与路径无关 ,惯性效应对动态J积分基本没有影响。低匹配焊接接头的动态J积分低于全母材而高于全焊缝。研究结果为承受动载的焊接结构安全评定奠定了基础。
Welded joint is a macroscopic mechanical heterogeneity, and mechanical inhomogeneity has an important influence on the dynamic fracture behavior of welded joints. The dynamic fracture response of a three-point bending test specimen with a low-matching welded joint with a weld center crack was simulated by the MARC finite element program. The dynamic J-integral fracture parameter was calculated by the virtual crack propagation method. As a comparison, the dynamic response of the three-point bending test specimen under the same conditions was calculated. Due to the effect of inertia, the dynamic load response curve is periodic and the dynamic load response of the welded joint is between the whole base metal and the all-weld. The dynamic J-integral calculated by the virtual crack propagation method has nothing to do with the path, and the inertial effect has no effect on the dynamic J-integral. The dynamic J integral of the low matching welded joint is lower than the total base metal but higher than the full welded joint. The research results laid the foundation for the safety assessment of welded structures subjected to dynamic loading.