Advanced Dynamic Stability Analysis

Several design approaches can be used to analyse the stability of subsea pipelines [1]. These design approaches vary in complexity and range between simple force-balance calculations to more comprehensive dynamic finite element simulations. The latter may be used to more accurately simulate the dynamic response of subsea pipelines exposed to waves and steady current kinematics, and can be applied to optimise pipeline stabilisation requirements. This paper describes the use of state-of-the-art transient dynamic finite elements analysis techniques to analyse pipeline dynamic response. The described techniques cover the various aspects of dynamic stability analysis, including: • Generation of hydrodynamic forces on subsea pipelines resulting from surface waves or internal waves. • Modelling of pipe-soil interaction. • Modelling of pipeline structural response. The paper discusses the advantages of using dynamic stability analysis for assessing the pipeline response, presents advanced analysis and modelling capabilities which have been applied and compares this to previously published knowledge. Further potential FE applications are also described which extends the applicability of the described model to analyse the pipeline response to a combined buckling and stability problem or to assess the dynamic response of a pipeline on a rough seabed.