Asymptotic Analysis for Buckling of Undersea Corroded Pipelines

Abstract

This paper deals with the buckling phenomenon of undersea corroded pipelines. The corrosion degree of the pipelines is characterized by two parameters: the angular extension and the corrosion depth. Previous work has shown that symmetric and antisymmetric buckling modes occur in pipelines when the corrosion is uniformly extended over part of pipelines along the circumferential direction. The presented research analyzes the stability condition in pipelines with generalized corrosion. Using WKB theory for asymptotic expansion, the buckling mode and the eigenfunctions are derived for the corroded pipelines subjected to external hydrostatic pressure. Furthermore, asymptotic solutions are derived for pipelines with constant corrosion and compared with validated solutions obtained in previous work using equilibrium analysis. It shows that the buckling modes and buckling pressure from asymptotic analysis are identical to the exact solutions. Symmetric and antisymmetric buckling modes are found to occur for pipelines when the corrosion is not uniform but symmetric about its centerline.