Numerical Analysis of Failure Mechanisms in High-Strength Pipelines Subject to the Interplay of Internal Corrosion and Spanning

Abstract

In engineering applications, the simultaneous suspension and corrosion of pipelines under unstable geological conditions present significant challenges, leading to large deformations, stress concentrations, and potentially catastrophic failures. Previous research often overlooked the simultaneous impact of these factors, resulting in inaccuracy in the failure analysis and further maintenance strategies. To fill the gap, this paper employs numerical analysis to create and simulate a series of pipe–soil coupling models uniquely considering internal corrosion for a more precise investigation of mechanical and failure behaviors in high-strength spanning pipelines. This research pioneers a comprehensive parametric analysis, exploring key factors such as operating conditions and geometric features on deformation, stress, strain, and stress concentration factor (SCF), all vital for failure determination. The results offer crucial insights, showing that maximum stresses in corroded spanning pipelines occur within the corrosion area, unlike in intact pipelines, where they typically appear at the span end. Increases in spanning length, corrosion dimensions, and internal pressure lead to upward trends in the maximum longitudinal stress, strain, and vertical displacement. The axial location of the internal corrosion also significantly affects the pipeline’s mechanical state. The longitudinal strain escalates along the axial location, being 1.97 times smaller at 2/10ls compared with 5/10ls. This study diverges from standard analyses by innovatively spotlighting the significant impact of corrosion width on spanning pipeline safety, particularly affecting longitudinal SCF. Maximum SCF increases by 36.1% with the corrosion width expanding from 5° to 50°, showcasing a more pronounced effect than that of corrosion length. This study advances pipeline integrity knowledge and lays the groundwork for future research, offering crucial tools for life span prediction and failure prevention in spanning pipelines. Our study reveals a more accurate way to simulate and predict when and where pipelines might fail due to the combination of internal corrosion and spanning. Traditionally, it was thought that the ends of suspended pipelines were most at risk, but our research shows the weak spots are within the corrosion area. The obtained stress concentration factor can be further used to estimate the fatigue life of a spanning pipeline. The simulation results also suggest that corrosion width is vital for spanning pipelines’ mechanical behaviors.