Antisymmetrical 3-D stress field near the crack front of a thin elastic plate

Based on detailed three-dimensional finite clement analysis, the near-tip field of a thin elastic plate remotely subjected to Mode II antisymmctrical loading is investigated. The computed results show the transition to a three-dimensional state to occur near the radial distance from the crack tip of 1.5 times the plate thickness. In the close vicinity of the crack front, the asymptotic stress field is characterized by a combination of plane strain Mode II and anti-plane Mode III singular ( 1 √r) fields. The domain of such fields extends approximately 0.5% of the thickness in the radial direction. The mixed-mode stress intensity factors along the crack front are determined from 3-D conservation integrals, and unlike the case of symmetrical loading, their magnitudes are greater towards the free surface. Near the intersection of the crack front and free surface, the stress field converges to the antisymmetrical corner singularity solution. The asymptotic form of stress near the intersection under general loading conditions is presented, along with the corner stress intensity factors.