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本文通过对奇异性的讨论及计算实践指出:如适当地划分网格,用退化三角形奇异单元可以较准确地求得缝顶单元的位移和应力,克服四边形奇异单元(?)_I-r 曲线在缝顶单元弯曲下降的缺点。推求了用缝顶单元结点位移计算 K_I 的公式。用这一方法对已有解析解答的典型问题进行了 K_I 值的计算,计算结果和解析解答良好的吻合。并将这一方法应用于结构形状比较复杂的结构,对于有凹角的裂缝体除缝顶外在凹角处采用奇异单元可以提高计算 K_I 的精度。
In this paper, through the discussion of singularity and computational practice, it is pointed out that if the mesh is properly partitioned, the displacement and stress of the element at the top of the seam can be obtained more accurately by using the degenerate triangular singular element, overcoming the quadrilateral singular element (?)_I-r curve. The disadvantage of the curved top unit bending down. The formula for the calculation of K_I using the displacement of the joint at the top of the joint was deduced. By using this method, the K_I value is calculated for the typical problem of the existing analytical solution. The calculation result is in good agreement with the analytical solution. This method is applied to structures with complex structures and shapes. The use of singular elements at the concave corners in the fractured bodies with concave corners can improve the accuracy of calculating K_I.