Finite element simulations of corrosion defect with different inclination angles in submarine pipelines using multi-physics field coupling and deformation geometry

Abstract

Fitness for service assessment of corrosion defects is very important for the safe operation of submarine pipelines. A three-dimensional model was built to analyze the corrosion defect on the outside surface of the pipeline which was influenced by mechano-electrochemical (M-E) effect. M-E effect has the greatest impact on the 0° corrosion defects which decreases with the angle increasing from 0° to 90°. The stress and corrosion rate of corrosion defect significantly rise with the increase of defect's initial corrosion depth, especially in the center. The initial corrosion depth and corrosion defect angle have an obvious synergistic effect. Thus, it should be paid more attention when the angle of the defect is 0° for pipeline integrity management. In addition, the angle of corrosion defect and axial tensile displacement have an antagonistic effect. A synergistic effect exists between the angle of the corrosion defect and the pipe's internal pressure.