Ring cracks at the surface of a half-space

This paper uses a distribution of ring dislocations to determine the crack tip stress intensity factors for a ring crack at the surface of a half-space subjected to a point force at the axis of symmetry. Three cases are considered: a short crack (relative to its radius), fully open to its root; a longer crack open at the surface but closed and slipping to the root; and a longer crack open at the surface and slipping to some self-determining point in the closing region. The stress intensity factors and points of closure and stick are determined.