The effect of the size and orientation of corrosion damage on the residual strength of steel pipes

Abstract

Corrosion is the main culprit responsible for the failure of steel pipes. The catastrophic nature of the failure of such critical infrastructure facilities makes the determination of the residual strength of pipelines with corrosion damage a subject of interest to inspectors, owners, and operators alike. Given that it is the only structural component of a steel pipe, any loss of the cross-sectional area of the steel due to corrosion has a direct and an immediate impact on the overall strength of the pipe. There are some existing techniques used to evaluate the corrosion damage of steel pipelines and to estimate their residual strength. Some methods consider only the longitudinal extent of corrosion, but ignore its circumferential extent; other methods consider both effects, simultaneously. This study presents the numerical modeling of a steel pipe with corrosion damage, and examines the effects of the size and orientation of the corroded area on the residual strength without considering the external loading. The extent of both, the longitudinal and circumferential, defect extension is examined, and their effects on the static and cyclic strength of a pipeline are presented. The numerical model uses the finite elements method to predict the pipe’s elastic-plastic and rupture behaviors. The numerical model is validated using classical and accepted analytical theory. The numerical results show good agreement with the analytical solution, and the model is shown to be a reliable approach to be used in a utility’s asset management program.