2010 年 76 巻 772 号 p. 1618-1625
In general, cracks are initiated from stress concentration sites: notch, hole and so on. The stress intensity factors of the cracks which are initiated from typical notches were computed numerically in the earlier studies. Then, as for the stress intensity factor of the short crack from the notch root, some simple formulae were proposed by some researchers. However, there are few data on the stress intensity factors of the cracks from the complex notches. In this paper, the stress intensity factors of the cracks from a center double U-shaped notch in a finite plate under a tensile stress were computed by the body force method. Then, the influences of the double notch and the prate edges on the stress intensity factors were examined, and the stress intensity factors were expressed with the simple formulae approximately.