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Coupling Method of Meshless and Level Set for Crack Propagation of Welded Structure(PDF)


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Coupling Method of Meshless and Level Set for Crack Propagation of Welded Structure
LIU Hui SHEN Shao-ding LEI Dian
Hubei Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
crack propagation meshless method level set method welded structure initial crack
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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Last Update: 2020-10-15