The authors have proposed an influence function method by which stress intensity factor, K, of surface cracks can be calculated easily for arbitrarily distributed surface stresses. They have developed the database of influence coefficients, Kij, for various types of surface cracks through a series of finite element analyses. And they also have developed a software system “SCAN”, based upon the above developed database, by which K-values of surface cracks can be evaluated promptly, and further, fatigue crack propagation can be simulated easily by a personal computer. In this paper the authors have studied how they can apply the SCAN system to the problem of the surface cracks initiated from the edge of a circular hole of a rectangular plate. Since circular notches have various radiuses of curvature, the concentrated stress distribution at the notch root is different depending upon the radius of curvature. Therefore, strictly speaking, K-values have to be evaluated for each case, one by one, which means enormous amount of FEM analysis are necessary. But the authors have found that the database of a surface crack in a flat plate already installed in the SCAN system can be applied to this problem with satisfactory accuracy, which means the K-values of this problem can be evaluated promptly by the SCAN system.
