Abstract

Pipelines are an economical means of transporting oil and gas. A commonly encountered performance issue with such structures, however, is their susceptibility to buckling under hydrostatic and hydrodynamic pressure loads. In such a failure scenario, the pipe will suddenly collapse under the action of the loads and can render the transport structure as ineffective. The engineering design of pipes must therefore account for the action and magnitudes of such anticipated service loading, referred to as buckle propagation pressure, in achieving an adequate and sound performance. As for the notion of economy, since buckle propagation pressure is closely related to the pipe wall thickness, it has a direct bearing on overall project costs. In this study, to simulate in situ conditions of subsea pipelines, only uniform hydrostatic pressure was taken into consideration as the source for loading. A finite element method (FEM) model was then used to examine the buckling modes on pipes of two different diameters varying at four diameter-to-thickness ratios. With the pipes modeled as having clamped supports, predicted values of stress, strain, reaction force, and displacement at the ends and at midspan, were obtained. The results found show an inverse relationship between the diameterto- thickness ratios and buckling capacities of the pipes.

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