Surface singularity and crack propagation

The three-dimensional singular stress field near the terminal point 0 of the crack front edge at the surface of an elastic body is investigated, using spherical coordinates r, θ, φ and assuming all three displacements to be of the form rλppF(θ, λ) where p = distancefromthesingularityline (crack front edge or notch edge) and p = givenconstant. The variational principle governing the displacement distribution on a unit sphere about point 0, which...