Numerical assessment of crack arrest in composite-repaired submarine pipelines

The present research evaluates the effectiveness of glass-epoxy composite wraps as a crack arrest mechanism for submarine pipelines subjected to combined multi-axial loads, including internal pressure, axial tension, and bending moment. Through-thickness cracks with different lengths and orientations (0°, 30°, 45°, 60°, 90°) are modeled at the critical 12 o’clock position of the pipeline. The cracks are analyzed using the commercial finite element software ABAQUS, with stress intensity factors (SIFs) adopting as the main fracture criterion within the framework of linear elastic fracture mechanics (LEFM). Fracture modes I and II are investigated for both unrepaired and repaired pipelines, with mode I identified as dominant. The results demonstrate that composite wraps can reduce SIFs by up to 27%, significantly lowering crack driving energy and prolonging the residual life of the pipeline. For the range considered, each unit increase in the relative crack length leads, on average, to 7.95% and 3.5% reduction in the mode I SIF (KI) and mode II SIF (KII), respectively. Crack closure induced by the repair system becomes more pronounced for larger cracks and higher mode mixity. This study highlights an affordable and durable approach to pipeline maintenance, offering long-term advantages compared with traditional repair techniques such as mechanical clamps or full replacement.