Interaction Guidelines and Residual Strength of Oil and Gas Pipeline with Multi-Corrosive Defects

Using ABAQUS software, the control variable method and dimensionless analysis method were used to solve the equivalent stress of pipelines with only axial or circumferential multiple corrosion defects, and the interaction criteria, determination process and influencing factors between multiple corrosion defects of pipelines were proposed. Considering the interaction effect between corrosion defects, combined with the control variable method, the residual strength of pipelines with multiple corrosion defects under complex corrosion conditions was numerically simulated, and the residual strength variation coefficient was proposed. The main and secondary factors affecting the residual strength of corroded pipelines were analyzed by orthogonal test design method. The results showed that when there were only axial or circumferential corrosion defects, the axial spacing coefficient was the main factor affecting the stress state of the pipeline. When the corrosion axial spacing was greater than Dt, there was no interaction between corrosion defects. When there were corrosion defects in both axial and circumferential directions, the corrosion length coefficient and the corrosion width coefficient were the main factors affecting the residual strength of the pipeline, followed by the corrosion depth coefficient and the axial spacing coefficient.