Collapse failure analysis of subsea corroded pipeline under combined external pressure and axial force

摘要

The subsea pipelines are usually located in a corrosive external and internal environment. Corrosion presents to be the most common defect type in subsea pipelines, and it is regarded to be one of the main causes of subsea pipeline failure. Due to subsea subsidence, mudslides, and seismic activities, the pipeline is presented under combined external pressure, bending moments and axial force combined loading cases. The accurate determination of the collapse pressure of corroded pipelines under combined loading is important in engineering practice. On the basis of the finite element method, collapse failure of subsea corroded pipelines under combined loads is investigated. The influence of corrosion length, corrosion width, corrosion depth and diameter-thick ratio on the collapse failure pressure is studied. It is observed that corrosion depth has the most significant impact on pipelines' collapse capacity. Furthermore, regression equations for predicting the collapse pressure of subsea corroded pipelines are proposed based on numerical results. The solution can be referred to in structural integrity assessment of subsea corroded pipelines.