Boundary Correction Factors for Elliptical Surface Cracks Emanating from Countersunk Rivet Holes

Abstract

To predict the crack growth and residual strength of riveted joints subjected to widespread fatigue damage, accurate stress and fracture analyses of corner and surface cracks at a rivet hole are needed. The results presented focus on the calculation of stress-intensity factor (SIF) solutions for cracks at countersunk rivet holes for tension, bending, and wedge load conditions. A wide range of configuration parameters were varied, including the crack size, crack shape, crack location, and length of the straight shank hole. A finite-element-based global-intermediatelocal hierarchical approach was used. The results are expressed as boundary correction factors (BCFs), which are nondimensional representations of the SIF. The BCFs were determined along the crack front in terms of the physical angle, which was measured from the inner surface of the plate to a point on the hole boundary or on the outer surface of the plate. In general, the values of BCFs increased along the crack front, moving from the inner surface of the plate toward the hole boundary or the outer surface. The values of the BCFs were highest for the crack fronts closest to the hole boundary. The trends in the solutions were the same for the three loading conditions.