中文摘要：

阐述了FRANC3D计算应力强度因子（SIF）的原理，研究了FRANC3D网格划分技术对计算裂纹SIF精度的影响。将数值计算结果与理论结果进行比较，表明裂纹面的网格疏密对计算精度影响很大，尤其是当裂纹边缘后的第一行网格节点越接近裂纹边缘时计算精度提高越快；而外部（除裂纹面之外）的网格疏密对计算精度影响不大。此外，单元采用的形函数对计算结果也有影响。

英文摘要：

The principle for code FRANC3D calculating SIF is introduced and the effect of FRANC3D mesh technique on accuracy of SIF is analyzed. Results suggest that the accuracy of SIF is heavily affected by the density of mesh at the crack tip （especially by the first line meshes behind the crack tip）, but less affected by the exterior meshes （ except for crack surface）. The effect of element types on accuracy is also studied.