Engineering approach for circumferential flaws in girth weld pipes subjected to bending load

Abstract The current investigation pursues extending the applicability of fully plastic solutions for J-integral and crack-tip opening displacement (CTOD), originally cataloged in a series of handbooks (also known as EPRI handbooks), in defective girth weld pipes subjected to bending load for a wide range of surface crack dimensions and weld strength mismatch levels. The suitability of the given set of solutions in this work is constrained by a certain number of parameters that are derived from the coupled effect of weld strength mismatch and configurational effects upon near-tip stress-strain fields in heterogeneous media. These results reveal a weak dependence of coupled effect of weld strength mismatch and weld groove size upon crack driving force, when the ratio of the mismatch between weld and base normalizing stresses is considered moderate (≤1.3), whereby the proposed estimation method becomes essentially valid for failure assessment procedures and fitness-for service (FFS) evaluations.