Stress intensity factor equations for a semi-elliptical surface crack in a shaft under bending.

Abstract

A simple procedure for the determination of stress intensity factor K for the problems whose solutions cannot be obtained easily by numerical analysis is proposed. The method is based on the concept that if we choose two referential two-dimensional problems and two geometrically similar three-dimensional problems, the ratio of K in the three-dimensional problem is approximately equal to that in the two-dimensional problem. The accuracy of the solutions depends on the choice of referential problems. The applicability of this method is checked by applying it to a semi-elliptical surface crack in a finite-thickness plate and an edge crack in a plate with finite width. Finally, the stress intensity factors for a semi-elliptical surface crack in a round bar under bending are obtained by the proposed method, in which a plate with an edge crack under tension and bending and a shaft containing a semi-elliptical surface crack are chosen as referential problems.