Comparison of stress intensity factors for longitudinal semi-elliptical surface cracks in cylindrical pressure vessels

The object of this paper is to compare stress intensity factor that be calculated by Raju-Newman's equation, finite element method, and Vessel INTegrity analysis INner flaws(VINTIN) program for longitudinal semi-elliptical cracks in cylindrical vessel under inner pressure. For this, three-dimensional finite-element analyses were performed to obtain the stress intensity factors for various surface cracks with t/R=0.1. The finite element meshes were designed for various crack shapes with t/R of 0.1. The crack depth to thickness ratio, a/t, was set to 0.2 and 0.5 matching Raju-Newman's equation. The crack depth to length ratio, a/c, was set to 0.2 and 0.4 in the same way and 0.33 was added to extend the range of crack configuration. Finite Element Analyses(FEA) were performed using the commercial FEA program ABAQUS. The results showed that the Raju-Newman solutions were about 4-10% lower than FEA's using symmetric model of one-eighth of a vessel and close to those of FEA using symmetric model of one-forth of a vessel. And VINTIN solutions were nearly equal to those of Raju-Newman