Three-Dimensional Stress and Stress Intensity for Tensioned Flat Plates with Edge Cracks

The stress in the thickness direction is an important factor influencing the fracture behavior of structural members. A stress σ_y tensioned flat plate with edge cracks is widely used as an analysis model. The stresses σ_x and σ_y for the plate model can be acquired from Neuber’s solution. However, the solution is applicable only for a perfect plane stress or plane strain state. As a consequence of the thickness of the plate a three-dimensional (3-D) stress state will arise near the crack tip, resulting in a variation of the distribution of σ_x and σ_y stresses. A full analysis for the 3-D stress fields for a tensioned flat plate with edge cracks has been therefore carried out. The results show that the 3-D stress field near the crack tip is mainly determined by two factors: the thickness of the plate and the curvature radius at the crack tip. A further analysis has been carried out for the stress intensity near the crack tip. In this paper we give some equations matching to the 3-D stress and stress intensity, which describe precisely the stress state near the crack tip, and which can be applied effectively in engineering analysis.