Three-dimensional weight function analyses and stress intensity factors for two unsymmetric surface cracks and surface-corner cracks at a circular hole

Two unsymmetric surface cracks and a combination of surface and corner cracks emanating from a circular hole are frequently encountered in many engineering structures, especially in airframes. Their stress intensity factors are critical for damage tolerance analyses. However, compared to cases of a single crack and symmetric double cracks that have been extensively analyzed in the literature, the present unsymmetric surface cracks and surface/ corner cracks emanating from a circular hole are much more complicated because more geometric variables are involved. In this paper, the slice synthesis weight function method for two unsymmetric hole-edge corner cracks developed recently by the present authors is further extended to calculate the stress intensity factors (SIFs) of two unsymmetric surface cracks and a combination of surface and corner cracks at a hole. The obtained SIFs are verified by comparing to limited solutions in the existing literature and also extensive finite element analysis. Very good agreements are achieved. Compared to 3D finite element analysis, the present slice synthesis weight function analysis is remarkably more efficient, and therefore can enhance the current capability of fatigue and fracture analyses for structures with unsymmetric surface and corner cracks at a circular hole.