Development of Stress Intensity Factors for Cracks With Large Aspect Ratios in Pipes and Plates

The stress intensity factors (SIFs) for pipes containing semi-elliptical surface cracks with large aspect ratios were calculated by finite-element analysis (FEA). The cracks were circumferential and axial surface cracks inside the pipes. The parameters of the SIFs are crack aspect ratio, crack depth, and the ratio of pipe radius to wall thickness. In comparing SIFs for plates and pipes, it can be clarified that SIFs for both plates and thin pipes with t/R_i ≤ 1/10 are almost the same, and the SIFs for plates can be used as a substitute for pipes with t/R_i ≤ 1/10, where t is the pipe wall thickness, and R_i is the inner radius of the pipe. This means that it is not necessary to provide SIF solutions for pipes with t/R_i ≤ 1/10, and it is suggested that the number of tables for influence coefficient values for pipes can be significantly reduced.