Closed-form stress intensity factor solutions for deep surface cracks in cylinders subjected to global bending

Azuma, Kisaburo*; Li, Y. ; Hasegawa, Kunio; Shim, D. J.*

Materials made of alloy 82/182/600 used in pressurized water reactors are known to be susceptible to primary water stress corrosion cracking. The depth, , of flaws due to primary water stress corrosion cracking can be larger than the half of crack length , which is referred to as cracks with large aspect ratios. The stress intensity factor solution for cracks plays an important role to predict crack propagation and failure. However, Section XI of the ASME Boiler and Pressure Vessel Code does not provide the solutions for cracks with large aspect ratios. This paper presents the stress intensity factor solutions for circumferential surface cracks with large aspect ratios in cylinders under global bending loads. Finite element solutions were used to fit closed-form equations with influence coefficients gb. The closed-form solutions for coefficient gb were developed at the deepest points and the surface points of the cracks with aspect ratios ranged from 1.0 to 8.0.