为了准确快速获取含缺陷结构材料裂纹前缘的SIF，本文基于扩展有限元法，分别从收敛性、计算精度以及网格尺寸对计算结果的影响角度出发，通过标准CT试样获取三维裂纹前缘SIF，并与传统的围道积分法和公式解析解的计算结果对比分析，得出基于扩展有限元法所获取的三维裂纹前缘SIF变化规律。结果表明：随着网格尺寸的增加，扩展有限元法可以保证足够的收敛性与稳定性；沿厚度方向SIF大小呈逐渐递增再递减对称分布，表明含缺陷结构中的裂纹总是从内部中间开裂；扩展有限元法对网格的依赖程度低，在网格数量与类型选取适当的前提下，使用扩展有限元法得到的SIF计算值与理论值吻合度较高。
To obtain the SIF of the crack tip of the defective structural material accurately and quickly. This paper is based on the extended finite element method (XFEM), starting from the perspective of convergence, calculation accuracy, and the influence of mesh size on the calculation results. The three-dimensional crack front SIF was obtained by standard CT specimens, and compared with the calculation results of the traditional contour integral method and the analytical solution of the formula, the change law of the three-dimensional crack front SIF obtained based on the XFEM method was obtained. The results show as the mesh size increases, the XFEM method can ensure sufficient convergence and stability. The stress intensity factor along the thickness direction is gradually increasing and then decreasing symmetrically, indicating that the cracks in the defect-containing structure always crack from the inside. The XFEM method has a low degree of dependence on the grid. Under the premise that the number and type of grids are selected appropriately, the calculated value of the stress intensity factor obtained by the XFEM method is in good agreement with the theoretical value.
2022,44(3): 1-5 收稿日期：2021-04-29
DOI：10.3404/j.issn.1672-7649.2022.03.001
分类号：O346.1
基金项目：国家自然科学基金资助项目(52075434)；陕西省国际科技合作计划项目(2021KW-36)
作者简介：薛河(1961-)，男，教授，研究方向为机械设计及理论、结构完整性评价
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