Prediction of burst pressure of corroded thin-walled pipeline elbows subjected to internal pressure

The thinning of pipeline walls, resulting from corrosion, reduces their capacity to withstand internal pressures. Accurate prediction of the remaining strength of corroded pipelines is important to prioritize mitigation efforts for critical defects. While burst pressure models for straight pipelines have been well established, the research on the burst capacity of pipeline elbows is still limited, and most studies were established on rectangular-shaped corrosion. This study focuses on developing a new model for assessing the burst capacity of elbows containing single semi-elliptical corrosion, based on extensive three-dimensional elastic-plastic finite element (FE) analysis validated by full-scale burst tests of straight and elbow pipelines. The Pipe CORRosion Criterion (PCORRC) method, originally developed for straight pipelines, was re-calibrated to predict the remaining strength of corroded pipeline elbows. A revised factor was introduced to account for hoop stress variations caused by elbow curvatures. Results indicate that the revised model offers observable accuracy improvement over the existing models reported in the literature. The proposed model will improve the integrity management of corroded elbows.