The polyester rope has been widely used for the deep-water mooring system, for the advantages of excellent tensile strength, strong corrosion resistance, good fatigue property and low cost. To reduce the mooring cost and improve the mooring mechanical properties, this paper combines the approximate model and the multi-objective particle swarm optimization algorithm to achieve the multi-objective optimization of the taut polyester mooring system. The polyester rope volume and strength utilization ratio are defined as the optimization objectives, then the parameters of mooring radius, the polyester rope diameter and the length are optimized. The results show that the stress of the mooring line is obviously reduced after optimization, and the heave and sway of the semi-submersible platform are also reduced. Compared with the other two design parameters, the length of polyester rope has the most significant effect on the change of strength utilization rate.
Compared with the chain and the steel rope, the polyester rope material has the advantages of excellent tensile strength, strong corrosion resistance, good fatigue property and low cost for the mooring system. It was noted (Yuan, Incecik and Ji,2014) that polyester rope can reduce the weight of the mooring system and the mooring radius efficiently. In addition, it can also improve the efficiency of the mooring horizontal recovery force and increase the effective load of the platform.
Li et al (2020) and Bruno et al (2021) analyze the influence of multiple design parameters on mooring system tension characteristics and floating platform movement. Sun et al. (2015) optimized the length of deep-sea multi-component mooring system based on neural network and genetic algorithm to minimize the motion response of FPSO. Ajit et al. (2019) simultaneously optimized the cost and fatigue damage of offshore floating wind turbine mooring system based on the surrogate model and genetic algorithm. Most of the multi-objective optimization analysis objects of deep-water mooring system in the industry of floating platforms are offshore power generation platforms and FPSO, and there are few researches on the optimization design of deep-water semi-submersible platform mooring system using multi-objective optimization algorithm.
