A novel model for predicting the ultimate bending moment of subsea pipelines with corrosion-dent coupled defects

Abstract

Corrosion and dent defects often coexist on subsea pipelines, and the interaction significantly reduces the anti-buckling capacity of pipelines. The corrosion-dent coupled defects pose a substantial risk of failure for subsea pipelines. This study aims to develop both an analytical and a numerical model to evaluate the ultimate bending moment of subsea pipelines with corrosion-dent coupled defects. A High-order approximation method is proposed to characterize the dent deformation of the pipeline. Based on the plane strain assumption, an analytical solution for the ultimate bending moment of subsea pipelines with corrosion-dent coupled defects is derived. Subsequently, a finite element model of a subsea pipeline with corrosion-dent coupled defects is developed. By comparing the analytical solution with numerical simulation results, it is found that the two results are in close agreement. Considering different types of coupled defects, the effects of parameters such as ovality, corrosion length, corrosion width, and corrosion depth on the pipeline's ultimate bending moment are explored. Finally, numerical simulation results are used to extend the application of the analytical model and to develop a comprehensive evaluation method for the ultimate bending moment of pipelines with corrosion-dent coupled defects.