Buckling analysis of subsea pipeline with integral buckle arrestor using vector form intrinsic finite thin shell element

Abstract

Buckling damage is one of the biggest safety issues for subsea pipelines. Buckling behaviors of the subsea pipeline with integral buckle arrestors under external pressure are studied experimentally and numerically herein. Pressure chamber tests of four full-sized pipeline with identical thickness and different diameters are presented. An emerging vector form intrinsic finite element method (VFIFE) is introduced to simulate the whole buckling process both in dynamic and quasi-static cases, including local collapse, propagation, buckling prevention, and crossover. Numerical schemes for multifold nonlinearities and multithreaded computation are proposed and tested. Results of experiments and numerical simulations, as well as computations of the traditional finite element method and DNV specifications, are compared. Thusly it is indicated that the VFIFE model can accurately (within ± 1.5%) predict the buckling loads that initiate local collapse, propagation and crossover, and simulate the dynamic and quasi-static buckling modes for pipelines with practical range of diameter-to-thickness ratios greater than 20. For thick parts where integral arrestor with diameter-to-thickness ratios smaller than 20 located, the VFIFE thin shell element may underestimate the structural strength about 8.0%. The VFIFE can directly simulate the pipeline buckling behavior without special processing for the iterative calculation and the stiffness matrix convergence, and achieve the parallel efficiency over 90% for a common computer (12 threads, 4G RAM). Thus, the VFIFE can provide a new, practical and universal analytic strategy for subsea pipeline buckling analysis.