基于ABAQUS标准扩展有限元法的不良裂缝构型影响分析

在实际应用中，扩展有限元法分析裂纹问题存在总体刚度矩阵高度病态、矩阵奇异等问题，数值模拟没有实现分析结果与网格划分无关的理想要求.基于ABAQUS平台选取三点弯曲梁试验，引入离散弗雷歇距离对具有时程性的裂缝发展路径进行差异评价；分析标准扩展有限元法应用中与网格划分相关的不良裂缝构型对模拟结果的影响.结果表明:数值模拟时初始裂缝端点必须在单元边界处，避免削弱构件；不良裂缝构型会导致裂缝发展路径模拟失真，且随不良系数的减小失真情况加重；不良系数u要控制在0.25~1内；通过引入黏性阻尼可以提高数值模拟的收敛性和路径的准确性.

Analysis of Poor Crack Configuration Influence Based on ABAQUS Standard Extended Finite Element Method

In practical applications， the analysis of crack problems by the extended finite element method(XFEM) has the problems of highly ill-conditioned overall stiffness matrix， singularity of matrix， etc. The numerical simulation does not achieve the ideal requirement that the analysis result has nothing to do with meshing. The three-point bending beam test was selected based on the ABAQUS platform， and the discrete Freschet distance was introduced to evaluate the difference in crack development path with time history. The influence of the poor crack configuration related to meshing on the simulation results in the application of the standard XFEM was analyzed. The results show that the initial crack endpoint must be at the element boundary during numerical simulation to avoid weakening the components， and poor crack configuration will cause the distortion of the crack development path simulation， and the distortion will increase as the poor coefficient decreases. The poor coefficient u should be controlled within 0.25~1. The convergence and path accuracy can be improved by introducing viscous damping.