Research On Applicability Of Different Modeling Methods Of Unbonded Flexible Pipe

The oil and gas exploration equipment for the deep water is more and more important along with the steps of exploring the ocean resources.The unbonded flexible pipe has original structures,excellent performance and high technology,which make it to be the significant equipment in oil and gas exploitation.The unbonded flexible pipe has attracted the attention from no matter academy and industry since it appeared because of its wonderful characters.This research for flexible pipe has important significance to achieve manufacture domestically and explore oil and gas resource.Analytical calculation,numerical simulation and experimental test are the main research methods of the unbonded flexible pipe.The analytical calculation is hard to simulate the contact between layers,the typical highly non-linear behavior.The experimental test may be less realistic owing to the expensive price of the flexible pipe.Thus the numerical simulation of the flexible pipe has been widely applied.Many researchers have created kinds of numerical simulation models of the flexible pipe,but there aren't consistent conclusions about the applicability of the different models.Three kinds of finite element models of the unbonded flexible pipe have been established based on the software ABAQUS.Then the applicability of the different models has been verified by analyzing the mechanical properties of the different models under different loads.The detailed works are shows below: 1)The parametric modeling programs aimed at the unboned flexible pipe have been built through the ABAQUS/Python language and the modeling user interfaces have also been created.It can quickly create the flexible pipe finite element models with different layers and structures by the modeling programs and user interfaces,which greatly improved the pipe modeling efficiency.2)Three kinds of pipe finite element models have been built through different modeling methods.And the parameters of pipe are based on a typical 8-layers unbonded flexible pipe.The models includes the simplest model,the local simplest model and detailed model.And the difference between them is the simulation for each layer of the flexible pipe.For the simplest model,each layer of the pipe has been simulated simplified.For the local simplest model,only the carcass and pressure armour have been simulated simplified.And for the detailed model,all layers haven't been simulated simplified and each layer has been created based on the real structures of the flexible pipe.3)The mechanical properties of the pipe under tension loads,torsion loads and bending loads have been analyzed based on the models created before.And the differences of results between different models have also been explained.The detailed model of the unbonded flexible pipe built in this paper is more consistent with the experimental results,which proves that the model has better applicability.Then the further research can be done based on the detailed finite element model of pipe.