Mode I Stress Intensity Factors for Point-Loaded Cylindrical Test Specimens with One or Two Radial Cracks

Abstract

Weight (or Green's) functions are obtained, using an accurate modified mapping collocation numerical technique, for cylindrical specimens with either one or two internal or external radial cracks. Radii ratios (the ratio of external/internal radius) of 1.25, 1.5, 1.75, 2.0, 2.5, and 3.0 are considered. The weight functions are used to obtain stress intensity (K) factors for radial loading by point forces symmetrically located about the crack line and about an axis at right angles to the crack line, through the center of the specimen. The maximum errors associated with the solutions are estimated at 1%. Notable features of the results obtained include a significant range of crack lengths with near-constant K-values, and configurations in which K changes sign as the crack length is increased. The point force configurations are suited to serve as cylindrical test specimens, either for fracture toughness or fatigue crack growth testing.