A discussion on 'The stress intensity factor study of an elliptical cracked shaft' by Y.S. Shih and J.J. Chen

摘要

Cylindrical shaped components such as pins, bolts. reinforcement wires and shafts are commonly used in engineering structures. Under repeated loading, cracks may develop at the surface and grow across the section. Recently, it has been shown that miniature surface cracked rod specimen offered a low cost and effective way for evaluating fatigue crack propagation properties (Shin and Chen, 2003). To assess the growth behavior and structural integrity involving these cracks, their stress intensity factor solutions must be known. The three-dimensional nature of this kind of cracks results in a stress intensity that is not only varying along the crack front but is also highly sensitive to the crack shape. Solutions derived using finite element analyses (Raju and Newman, 1986; Astiz, 1986; Shiratori et al, 1986; Carpinteri, 1992a,b; Carpinteri and Brighenti, 1996; Couroneau and Royer, 1998; Shih and Chen, 2002), boundary integral method (Athanassiadis et al., 1981), general weight function (Caspers et al., 1990) or approximate analyses (Daoud et al., 1978; Bush, 1981; Murakami and Tsuru, 1987) are available. However, these solutions are often limited to one or two points (the deepest interior point and the surface interception point) on the crack front. Moreover, they are often available for a limited number of discrete aspect ratios and crack depth ratios.