Structural dynamics of offshore Wind Turbines: A review

The trend in the offshore wind turbine industry is towards using wind turbines with more energy harvesting capacity per unit and greater power per mass ratios to compete with other sectors of the energy industry. This upscaling trend has resulted in larger and more flexible structural components for these huge rotating machines. On the other hand, while often subjected to strenuous logistical and construction conditions during their installation in harsh environments in the coastal areas of open seas, these large flexible structures must withstand aerodynamic, hydrodynamic, gravitational, and geotechnical loads while in service. Therefore, offshore wind turbines are dynamically very active structures. In this review paper, the most important concerns related to the structural dynamics of offshore wind turbines, including modal alignment, aeroelasticity, hydroelasticity, soil-pile interaction, mooring line-floater interaction, drive train vibrations, control of vibration amplitudes, and motion and structural dynamics experiments, are addressed and relevant recently-published literature is reviewed. Based on this review, the major topics that require further research and study in the field of offshore wind turbine structural dynamics are outlined.