Quarter Elliptical Cracks Emanating From Holes in Plates

The finite element-alternating method, a linear elastic solution technique, is refined and applied to problems of quarter-elliptical cracks in irregular bodies. The method involves the iterative superposition of a finite element solution for stresses in an unflawed body and an analytic solution for stresses in an infinite solid containing a flat elliptical crack. Mode-one stress intensity factors are presented along the periphery of quarter-elliptical cracks emanating from open fastener holes in flat plates. Results are shown for a variety of crack geometries and two hole-diameter to plate-thickness ratios. Comparisons are made with experimental results of other authors.