Extension of Fully-Plastic J-Solutions for Defect Assessments of Clad Pipe Girth Welds

Rodolfo F. Souza¹; Claudio Ruggieri¹

¹ University of Sao Paulo

doi:10.20906/CPS/COB-2015-0069

Resumo

This work focuses on the development of an evaluation procedure to determine the elastic-plastic crack driving force (as characterized by the J -integral) in pipeline girth welds with circumferential surface cracks subjected to bending load for a wide range of crack geometries and weld mismatch levels based upon the GE-EPRI framework and the reference stress approach. The objectives of the present investigation are twofold. First, the study broadens the applicability of current evaluation procedures for J which enter directly into structural integrity analyses and flaw tolerance criteria to provide numerical solutions for crack driving forces in mismatched girth welds with circumferential surface cracks. As a second objective, we analyze the potential effects of an undermatched girth weld on critical flaw sizes for a typical clad pipe employed in subsea flowlines having a girth weld made of UNS N06625 Alloy 625. Attention is given here to structural integrity analyses derived from three related ECA procedures incorporating the GE-EPRI framework and the reference stress approach. The extensive nonlinear, 3-D numerical analysis provide a large set of solutions for J in cracked pipes and cylinders with mismatched

Palavras-chave: Integral J; EPRI Methodology; Defect assessment; Circumferentially cracked pipe