摘要
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 mechanical heterogeneous body, and the mechanical heterogeneity has great effect on dynamic fracture behaviour of welded joint. By using MARC finite element program, the dynamic fracture response of three-point-bend (TPB) sample deriving from low matching welded joint containing longitudinal crack is computed, and the fracture parameter of dynamic J -integral is calculated by adoption of virtual crack extension (VCE) method. For contrast, dynamic response of whole base metal and whole weld metal three-point-bend (TPB) samples are computed. Because of the effect of inertia, dynamic load response curves of computed samples wave periodically, and the value of dynamic load response of welded joint is between that of the whole base metal and the whole weld metal. Dynamic J -integral is path independent by use of VCE method, and inertia has little influence on the values of dynamic J -integral. The value of dynamic J -integral of low matching welded joint is lower than that of the whole base metal and higher than that of whole weld metal. The results establish the foundation of safety evaluation of dynamic load welded constructions.
出处
《焊接》
2003年第10期9-12,共4页
Welding & Joining
基金
国家自然科学基金项目 (No .5 95 0 10 11)
北京科技新星计划资助
