Prediction Model for Failure Pressure of Large-Diameter Gas Pipelines at Different Temperatures

Abstract

Long-distance gas pipelines in service inevitably are exposed to harsh conditions such as extreme temperature. It is also recognized that corrosion is one of most influential factors on the structural reliability and safety of pipelines, even coated pipelines. Therefore, there is an important need to investigate the temperature effect on the failure behaviors of gas pipelines with corrosion. In this study, a thermomechanically nonlinear finite-element model of a corroded gas pipeline with a polyethylene protective layer was established, in which a large diameter is considered for the long-distance gas pipeline. Thermal stresses obtained from cases with and without the protective layer were compared. Based on the stress-based failure criterion, the failure pressure values of corroded pipeline at different temperatures were obtained, and the deformation and strain of the corroded pipeline were evaluated. The random forest algorithm was adopted to analyze the parametric sensitivity of failure pressure. Taking temperature into account, an estimation model for predicting the failure pressure of corroded pipelines is proposed using the nonlinear least-squares method, which could be useful for performing a preliminary assessment of the failure pressure of long-distance gas pipelines in practice.