| 焊接结构裂纹扩展分析的无网格和水平集耦合方法 |
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| 引用本文： | 刘 晖,申韶丁,雷 电.焊接结构裂纹扩展分析的无网格和水平集耦合方法[J].建筑科学与工程学报,2020,0(5):106-112. |
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| 作者姓名： | 刘 晖 申韶丁 雷 电 |
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| 作者单位： | 武汉理工大学 道路桥梁与结构工程湖北省重点实验室,湖北 武汉 430070 |
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| 摘 要： | 针对焊接结构由于初始裂纹的存在而导致裂纹扩展,降低结构承载力,危及结构使用安全的问题,提出了分析有初始裂纹焊接结构的裂纹扩展及其扩展路径的无网格和水平集耦合方法。先建立焊接结构的无网格模型,将节点划分为常规节点、阶跃扩展节点和裂尖扩展节点; 然后采用移动最小二乘法计算近似函数,得到结构的位移场及应力场; 最后采用相互作用积分法求解应力强度因子,将最大周向应力准则作为失效准则计算开裂角,获得焊接结构的裂纹扩展路径。裂纹几何形状采用水平集法描述,裂尖位置采用在裂尖处相互正交的波前水平集函数和裂尖水平集函数定位,裂纹扩展路径跟踪采用水平集更新算法实现。以焊接节点为环状形式截面且存在初始焊接裂纹为研究对象,编制了基于所提方法的裂纹扩展程序。结果表明:采用所提方法分析焊接结构裂纹扩展计算得到的应力场光滑且协调,无需进行后处理,避免了有限元计算裂纹扩展时网格畸变和扭曲,提高了传统无网格法的精度和效率,实现了对裂纹扩展路径的准确跟踪。
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| 关 键 词： | 裂纹扩展 无网格法 水平集法 焊接结构 初始裂纹 |
Coupling Method of Meshless and Level Set for Crack Propagation of Welded Structure |
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| LIU Hui,SHEN Shao-ding,LEI Dian.Coupling Method of Meshless and Level Set for Crack Propagation of Welded Structure[J].Journal of Architecture and Civil Engineering,2020,0(5):106-112. |
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| Authors: | LIU Hui SHEN Shao-ding LEI Dian |
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| Affiliation: | Hubei Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China |
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| Abstract: | Due to the existence of initial cracks in welded structures, the crack propagation would reduce the bearing capacity of the structure and endanger the safety of the structure. A coupling method of meshless and level set was proposed for analyzing the crack propagation as well as its propagation path of welded structures with initial cracks. Firstly, the meshless model of the welded structure was built, in which the nodes were designated into regular nodes, step extension nodes and crack tip extension nodes. Then the moving least squares method was used to calculate the approximation function to obtain the displacement field and stress field of structure. Finally, the interaction integral method was used to calculate the stress intensity factor, and the maximum circumferential stress criterion was used as the failure criterion to calculate the cracking angle in order to obtain the crack propagation path of the welded structure. The geometrical shape of the crack was described by the level set method, and the location of the crack tip was determined by the pre-wave level set function and the level set function of the crack tip which were orthogonal to each other. Tracking crack propagation path was realized by the updating algorithm of level set. Taking the weld joint of annular section with initial weld crack as the research background, a crack propagation program based on the proposed method was developed. The results show that the stress field calculated by the proposed method is smooth and coordinated without the need of post-processing, which avoids the mesh distortion when calculating the crack propagation by the finite element method. Also, the accuracy and efficiency of the traditional meshless method is improved to realize accurate tracking the path of crack propagation. |
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| Keywords: | crack propagation meshless method level set method welded structure initial crack |
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