On the Collapse of Offshore Pipelines under External Pressure and Axial Force

Abstract

The elastic collapse of long cylinders under combined external pressure and axial force was investigated using analytical approach. Long cylindrical pipelines laid on the seabed are subjected to external pressure, initial defect will cause the local collapse of the pipelines. Due to the change of subsea environments and construction conditions, circular pipelines are subjected not only to the hydrostatic pressure, but also to forces of other forms, such as axial tension or compression, so on and so forth. This paper studies the local collapse and the morphological characteristics of a circular pipelines subjected to hydrostatic pressure and axial force. Governing equations based on Karman-Donnell`s shell theory are derived and are solved using Ritz method.