Simulation And Control For Motion And Force On Equivalent Depth Truncated Points Of Deep Sea Mooring Line

With the development of marine oil and natural gas exploration intodeep-sea, it is deeper and deeper of the deep-sea platform working depth. Oceanengineering pool scale is insufficient. The hybrid model testing is needed. There aretwo types of hybrid model testing technology: online and offline.In designing offline hybrid model testing, the improved adaptive chaotic particleswarm algorithm (ACPSO) is used. Two changing parameters are introduced todecrease search region during the iteration. The optimization has greatly optimizedthe previous sectional solutions and has speeded up the algorithm convergence andthe rate of convergence.Taking a turret FPSO in water depth of914.4m, in which thetruncated water depth is214.4m, as an example, the numerical experimentation resultindicated that the selected mathematical model and the optimized method used in thispaper are fast and effective.Taking what is needed straight from the model testing is the most ideal choice.The online hybrid model testing technology is required. The problem is how to getthe motion and force of truncated points. The nonlinearity and the geometricalnonlinearity of materials are considered. To get the motion and force laws onequivalent depth truncated points of deep sea mooring line, the lumped mass is used.Regarding the endpoint as input, and truncated points as output, the change lawof the motion and force on the truncated points which are relative to the endpoint isderived. The real-time motion and the force of truncated points are calculated bygiving the motion of endpoint in the online hybrid model testing. So it will offersome effective technologies for the online hybrid model testing technology.Take a mooring FPSO in water depth of120m for instance, and giving themotion of endpoint, which is sine wave and JONSWAP random wave, the mooringline is truncated. The tracks and time tension curves of some truncated points arecalculated. The power spectrum curves are analyzed by transforming time domain tofrequency domain. The functions of RAO are defined. The corresponding force response relationship between the truncated points and endpoint is calculated.According to the calculation and the similarity criteria, the simulation and control oftruncated points are analyzed by the plug-in unit of SolidWorks2010Motion.Angular displacement and displacement of the1#~6#telescopic are given bysimulation results. A theoretical basis for the design of the entity platform isprovided.