Residual ultimate strength investigation of subsea gas pipelines with internal random pitting corrosion using an advanced modeling approach

Subsea pipelines, essential for offshore gas transportation, are vulnerable to internal pitting corrosion induced by corrosive environments. Collapse under external pressure is a critical failure mode, and corrosion defects significantly reduce structural capacity. This study proposes a numerical approach to simulate random internal pitting corrosion using ABAQUS witha user-defined Python program. Extensive nonlinear finite element analyses, accounting for both geometric and material nonlinearity, are conducted to investigate the collapse behavior of corroded pipelines. Results indicate that collapse pressure is governed primarily by initial ovality, the length of pitting affect zone, and relative corrosion volume. Given the complex interplay among these parameters, a multilayer perceptron (MLP) is developed based on the numerical database to efficiently predict the residual strength of pitted pipelines.