An approximate expression of KImax for sphere/nozzle corner cracks

Based on the flat-nozzle model loaded by uniform biaxial tension, using the O-integral of the weight function method and introducing suitable free-surface correcting factors M, M, and a curvature correcting factor M, an approximate expression of K of sphere/nozzle circular corner cracks has been presented in this paper. The results so calculated are compared with those reported in the literatures and they show good agreement, the discrepancies being less than 10%. This shows that the approximate expression is effective and can be used in practice.