研究基于扩展有限元的多裂纹扩展分析方法以及ABAQUS环境下的程序实现。在位移函数中增加扩充项以描述裂纹周围的不连续位移场。初始裂纹以点集或方程的形式给出，并使用水平集函数将多裂纹信息离散到单元节点上，水平集函数还用来追踪裂纹扩展路径。使用局部水平集更新方法减小了计算规模，改进了裂尖单元的判断准则，借助商业软件Tecplot软件实现了裂纹扩展的动态显示功能。使用交互积分法计算混合模式下的应力强度因子，用最大周向拉应力准则判断裂纹扩展方向。探讨了网格密度和积分域尺寸对方法的影响，数值算例表明扩展有限元方法能够模拟任意形状的裂纹，并且能够反映多裂纹扩展的规律。%A numerical method and its implementation in ABAQUS using X⁃FEM to analyze multiple crack propa⁃gation was studied. The displacement discontinuity was approximated by appending enriched items to standard field. We give the initial cracks in the form of point⁃set or curve functions and dispersed them to the element nodes using Level Set Method ( LSM) . LSM was also used to track crack propagation paths. The local level set update technique was used to reduce the computing scale and the Judgmental Approach has been improved. The display of the process of crack propagation was realized using the commercial software Tecplot. Interaction integral technique was used to calculate mixed mode stress intensity factors. The maximal circumferential stress criterion was used to calculate the kinking angles of the propagating cracks. Influence of mesh and integral zone on simulation results were taken into consideration. Numerical examples were presented to demonstrate the benefits of the proposed implementation.
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