The Research On Modeling And Simulation Of Dynamic Response Of Ocean Underwater Pipeline

Underwater pipeline system is the important technical equipment of conducting the activitiessuch as marine scientific research, aquaculture and oil and gas development, which is widely usedin the occasions of the transport of oil and gas of the offshore platforms, mooring of FPSO andumbilical cable of underwater remotely operated robots. The characteristics of dynamic responseof the marine pipeline directly affect the security and stability of the marine engineering equipment.So it is very necessary to do hydrodynamic research on underline pipeline.The earlier period of the study of marine pipelines is basically confined to the static categoryof analysis, and the main objective is to get geometric configuration and tension in steady state.Obviously, it can not describe Ocean pipeline’s movement only use static analysis when sufferfrom the combined effects of the wind, the waves and the stream in real. To solve this problem, avariety of modeling method of the pipeline dynamic response has been developed, which is morewidely used are lumped-mass method and the finite difference method.This paper conducts static analyses of the ocean underwater pipeline and obtains the classiccatenary equation and static analytical solution by derivation which as a reference for comparisonin the model validation section. On this basis of lumped-mass method,building a unifiedmathematics-mechanics model of dynamic response of an underwater pipeline system. It deducesthe computation formula of all kinds of effects, and build the system’s control equation based onthe equilibrium of generalized active force and generalized inertial force. Then using Matlab as adevelopment platform, solve the control equation of the pipeline model for the numericalintegration with the Runge-Kutta method, and design examples of the flexible and rigid pipelinefrom the two aspects verifying the validity of the model.By comparing the simulation results withrelated literature and the results of Orcaflex software, the results are in good agreement indicatingthe validity of the model.In this paper, we had a numerical simulation on the laying operation of sub-surface buoy andthe tube operation of the laying and recovery of the submarine pipelines. In the former simulationshow that use tugs-drop anchor laying sub-surface buoy, the curvature of the the rope srctionconnected with the anchor, and easily damaged around this section, so it is needed to optimize thestructure of the connecting section of the anchor and selected appropriate cable material. Targeted operational recommendations also be provided in the simulation of the latter. These conclusionsand recommendations has a certain reference value on engineering work.