Nonlinear Dynamical Analysis And Study On Wave Induced Fatigue Of Deep-water TTR

With the rapid development of marine project, the exploration and development range of oil/gas has gradually changing from offing to blue water, a mass of oil/gas resource in blue water, deep-sea development of the china is imminent. Marine riser system is the main constituent of ocean infrastructure, and it is one of the weakest and most delicate components. The marine riser project has a great important status in development of marine oil/gas, it is the emphases of petroleum and nature gas industry in independent project of deep water.The first part of this paper clearly introduces wave theory in structure hydrodynamics as foundation. Discusses the fundamental equation and derivation in linear wave theory and Stokes wave theory and finally introduces calculation means of wave force of small members in ocean engineering structure. When calculating the small volume wave loads, Morison formulation, the selection of wave theory, the confirmation of drag coefficient and mass coefficient is introduced.The second part of this paper found governing differential equation in line of the TTR, in view of the internal and external load, confirms their solution conditions bases on the theory. Then, the solving approach of direct integral is introduced mainly.The third part of this paper models the TTR using a great general finite element analysis software-ABAQUS, in addition the environmental loads and the moving boundary condition on the top are given. Under the four typical work conditions, the time-domain nonlinear dynamical analysis of riser basing on nonlinear Stokes 5 wave theory. Finally we receives stress time history curves, displacement time history curves of the riser's top and bottom parts, and analyzes that curves, studies the dynamic characteristics of the riser.The forth part of this paper bases on the calculated results of the dynamical analysis, analyzes wave induced fatigue damage of the TTR, studies the riser's fatigue property that is affected by wave. That is very significant in engineering practice.