ANALYTICAL SOLUTION OF PIPELINE GLOBAL BUCKLING WITH DOUBLE ARCH IMPERFECTIONS

Submarine pipelines usually have initial imperfections which would induce global buckling of the pipelines under the action of high temperature and high inner pressure. This study focuses on the thermal buckling behavior of pipelines with double arch initial imperfections. Based on the assumption of global buckling deformation of ideal pipelines, analytical solutions for the second-and fourth-order modes are obtained for pipelines with double arch initial imperfections. By solving the energy equilibrium equations of pipeline global buckling, the relationship between the axial force in the pipe and the buckling wavelength of the pipeline is established for the process of buckling. The variation of axial force in the buckling segment and the slipping segment is investigated to reveal the mechanism of snap buckling. The case study shows that the second-order mode deformation is more likely to happen than the fourth-order mode deformation if the pipeline is under the same load condition. The snap buckling takes place only when the release rate of the axial force in the buckling segment is greater than the accumulative rate of the friction resistance in the slipping segment.