Stress-Intensity Factors for Elliptical Cracks Emanating from Countersunk Rivet Holes

Small cracks developing from rivet holes in lap joints of fuselage structure have been an issue of concern over the past decade. Stress-intensity factor solutions required to assess the structural integrity of such configurations are lacking. To address this need, the domain integral method was used in this research to obtain the mode I, normalized stress-intensity factor distributions for cracks emanating from a centrally located countersunk rivet hole in a square plate subjected to remote tension. Particular attention was focused on short cracks with an elliptical shape that have not propagated through the thickness. For these short cracks, the normalized stress-intensity factor distribution depended on the shape and size of the crack. Analysis was also conducted on long through the thickness cracks with a straight front for which the normalized stress-intensity factors were uniform.