气动荷载对浮式风机系泊疲劳寿命的影响分析

Influence of Aerodynamic Load on Fatigue Life of Mooring Lines of Floating Wind Turbines

利用仿真软件FAST和OrcaFlex建立了风机-浮式平台-系泊系统在时域上的耦合分析模型,结合Miner线性损伤累积理论、雨流计算法和系泊T-N曲线,分析了浮式风机的系泊系统在不同气动模型和代表性工况下的疲劳问题,研究了气动荷载和风场湍流强度对系泊疲劳寿命的影响.结果表明:气动荷载会大幅缩短系泊的疲劳寿命,考虑湍流气动荷载时的系泊疲劳寿命仅为不考虑其影响时的1/5,故在系泊疲劳分析中应合理选择湍流风模型;当海况风速接近风机额定风速时,气动荷载会显著增大平台水平位移,导致系泊张力大幅增大,加速系泊疲劳损伤,缩短系泊疲劳寿命;平台的侧移响应会增大平台的侧倾响应,从而加速系泊的疲劳.

Based on a coupled analytical model of floating wind turbine,an investigation into the influences of aerodynamic load and wind turbulence intensity on the fatigue life of mooring lines was performed by using the Miner's cumulative damage theory,the rain flow method and the T-Ncurves.The results of the fatigue analyses of mooring lines show that the including of the turbulent wind loads causes an 80% decrease in the fatigue life of mooring lines,indicating the importance of choosing a reasonable turbulent wind model;in sea states with wind speed which is close to the rated wind speed of the wind turbine,aerodynamic loads can greatly amplify the horizontal displacement of the platform,thus increase the tension of mooring lines,and decrease the fatigue life of mooring lines;the interaction among the responses can worsen the fatigue damage of mooring lines.This study can guide the fatigue design of mooring lines.