Buckling of Pipelines With Inconstant Corrosion Subjected to External Hydrostatic Pressure

Methodology to derive analytical solutions for the buckling of pipelines with inconstant corrosion subjected to external hydrostatic pressure is presented. The corroded pipeline is modeled as a non-uniform, infinitely long cylindrical shell with two regions: Region 1 of nominal thickness and Region 2 of reduced, inconstant thickness. Eigen-functions to determine the buckling pressure for the corroded pipeline are derived using asymptotic expansion. Symmetric and anti-symmetric buckling modes are found to occur for pipelines when the corrosion is symmetric about its centerline. In particular, solutions of the buckling mode and the eigenvalues for buckling pressure of the corroded pipeline are obtained when Region 2 has a reduced and constant thickness and are found to converge to the validated solutions obtained from equilibrium analysis.