| In recent years, with the raising of new national energy strategy, offshore windpower technology is developing rapidly. When floating foundation for offshore windturbines was proposed, it received worldwide attention and lots of manpower andmaterial were applied to conduct the research. The technical problems of floatingfoundation are very complex, including structure modeling, loads calculation,strength and durability analysis, and lack of effective calculation method. This articleis based on a semi-submersible floating foundation, researched the structural design,modeling and calculation method for structure strength, which has importanttheoretical and practical meaning to promote the progress of China’s offshore windpower technology of floating foundation, improve theory and technology andpromote the application of China’s floating foundation for offshore wind power.This paper focuses first on the investigation of floating foundations for offshorewind turbines, introduces the theories about calculation of wave, current, wind andaerodynamic load, Based on the5MW wind turbine of NREL, the minimumthickness of column shell and the minimum section modules were calculated by theload and resistance factor design method according to DNV offshore standard.SESAM is a professional software for naval and ocean engineering structuralanalysis and hydrodynamic analysis. The column, water-entrapment plates, tower,nacelle and blade are treated properly, the numerical hydrodynamic model areestablished by using GeniE. Variable propeller aerodynamic load on the blade arecalculated. In HydroD, composite model is chosen, transfer functions and responsespectrums of wave load and motion of floating wind turbine system are calculated.All loads on the structure are considered when structural analysis of the floatingfoundation is carried out, and then the strength of structure is checked according torules for structure design. Furthermore, spectrum-based fatigue analysis is preformedfor the areas where stress are higher based on the Stofat, and the results show that thestructure and fatigue strength of the floating foundation both meet the requirement. |
