Stress Singularity at the Free Surface of a Dynamically Growing Crack

The stress singularity at the intersection between the crack front and the free surface of a dynamically growing crack in a linear elastic isotropic material has been numerically evaluated by an especially developed finite element program. The singularity parameter (λ), defined by σ ~ R^λ−1, is presented as a function of the crack-tip velocity and the angle (β) between the crack front and the free surface. The angle (β) at which the singularity (λ) equals 0.5 was found to be 101 deg almost independently of the crack-tip velocity.