Stress-intensity Factors for Two Symmetric Corner Cracks

The literature contains several analytical and experimental evaluations of Mode I stress-intensity factors for corner cracks at holes in plates subjected to remote tension, remote bending, or pin loading in the hole. Unfortunately, these solutions give very different stress-intensity factors for the same crack configuration and loading.

The purpose of this paper is to present stress-intensity factors, calculated by a three-dimensional finite-element analysis, for shallow or deep quarter-elliptical corner cracks at the edge of a hole in a finite-thickness plate. The plate was subjected to remote uniform tension, remote bending, or simulated pin loading in the hole. A wide range of configuration parameters was investigated. The crack depth-to-plate thickness ranged from 0.2 to 0.8, while the ratio of crack depth to crack length ranged from 0.2 to 2. The ratio of hole radius to plate thickness was 0.5 or 1. To verify the accuracy of the three-dimensional finite-element models employed, convergence was studied by varying the numbers of degrees of freedom (the number ranged from 4400 to 9300). The stress-intensity factor variations along the crack front are compared with solutions from the literature.