Prediction of Springing-induced Extreme Responses of a TLP-type Floating Wind Turbine

摘要

Floating wind turbines are designed to survive 50-year-extremeenvironmental conditions during their 20-year service life, as specifiedby International Electrotechnical Commission (IEC) standards. For atension-leg platform (TLP)-type floating wind turbine, extreme waveloads can induce significant high-frequency resonant and transientresponses, e.g. springing and ringing, which greatly amplify thestructural responses of the floating wind turbines. This study aims topredict the springing-induced extreme responses of the WindStar TLPsystem by using FAST (Fatigue, Aerodynamics, Structures, andTurbulence), a fully coupled simulation tool. The hydrodynamic loadsconsidered include both first- and second-order wave-excitation loads.Different simulation sizes are compared. Different extreme-valueprediction methods are applied and the results are compared. Both thepeak-over-threshold (POT) and block maxima method (BMM) areapplied to extract local maxima, which are then fitted using a threeparameterWeibull distribution. The average conditional exceedancerate (ACER) method and the Gumbel method are applied and comparedwith the above method.