Study On Dynamic Characteristics And Damage Mechanism Of Polyester Mooring Cable For Offshore Floating Wind Turbine

Offshore wind power is an important part of China’s next five-year plan,but there is no actual service floating wind turbine in C hina.Therefore,based on foreign design experience and domestic environmental factors,a floating wind turbine platform model is designed,and its dynamic response analysis and optimization are carried out.O n this basis,a mooring line fatigue life prediction software is developed.The main research contents are as follows(1)Referring to the more mature design schemes abroad,combined with the sea conditions in C hina,the design of the floating fan and its mooring system which can adapt to the South C hina Sea is proposed.The basic theoretical basis and the environmental load of the South China Sea are summarized.(2)Based on the model,the dynamic respons e analysis is carried out to explore the influence of different mooring system parameters on its dynamic response.It is found that the material of mooring line,mooring scheme and pretension have great influence on the dynamic response;The reduction of t he horizontal span will lead to the increase of the amplitude of each dynamic response,but the influence is slight,which can be considered according to the actual situation;The lowest mooring point is the best choice for dynamic response;In this experiment,the increase in the number of mooring lines is very limited for the optimization of dynamic response.In order to ensure that all indicators can be kept below the safe value,the scheme with less mooring lines should be considered as far as possible to save the construction cost.(3)Based on the rain flow counting method,T-N curve and miner fatigue accumulation theory,a mooring line fatigue damage calculation software was developed by using MFC,and the accuracy of rain flow counting method is verified;The 100 year sea state is discretized into several short-term Sea States,and then the top tension of the mooring line under each sea state is obtained by using the Aqwa module of ANSYS,and the fatigue damage of each short-term sea state is obtained by importing the developed software for calculation.Finally,the total fatigue damage is obtained by superposition,and the fatigue life of the mooring line is calculated accordingly.The results show that the mooring scheme only considering tension can fully meet the design requirements.