Optimization Analysis And Application Of Mooring System Based On Genetic Algorithm

The mooring system is very important for floating platform. Mooring system provides restoring force for floating platform, which ensures the safety and normal operations of the platform. Design of mooring systems is a complex project, mooring systems need to restrict the movement of the platform as much as possible, and take least cost. At the same time, the parameters of the mooring system influence each other,it is difficult to determine the appropriate design parameters quickly.Aiming at the problems, this paper focuses on writing mooring line optimization program and application it in multi-parameter mooring line optimization and truncation design. The optimization results are verified by numerical simulation and tank test.Firstly, the mooring line static analysis theory is studied, and a mooring line static analysis program is written. The program is proved by comparing with OrcaFlex Software.And then the mooring line dynamic analysis theory is studied.Secondly, the basic theory of genetic algorithm is studied. A mooring line optimization program is written by MATLAB,and then it is used in optimization design of mooring system.The Optimization goal is to minimize the cost and provide enough limit to the platform, on the other hand, the force of mooring line does not exceed the allowable stress. Wet weight of unit length, length and axial stiffness of mooring line are chosen as the design variables, then the mooring system of FPSO is optimized. And some good results were obtained. The numerical model of FPSO and mooring system are established and time domain dynamic analysis are done to verify the correctness of the optimize program, the results of time domain dynamic show the optimization ability of this program is good.At last, truncation design process based on genetic algorithms is written, as truncation design is also a optimize process. The operating water depth of this FPSO is 1700 meters.The full depth model test cannot be carried out in the tank. The truncation design program is written based genetic algorithm, The results gotten from optimization program is proved to meet the equivalent principle, and are used in FPSO tank test, the results of model test shows the truncation mooring system design is pretty good.In sumary, the mooring line static analysis program, optimization design program of mooring system based on genetic algorithms,truncation design process based on genetic algorithms are written in this paper, and they are validated by dynamic analysis of the time domain and FPSO tank model tests. Results of verification show that the program is correct and reasonable.