Study on the aerodynamic damping for the seismic analysis of wind turbines in operation

The continuous cost reduction of wind turbines has consolidated the competitiveness of wind energy. With the increasing installation of wind turbines in seismic-prone regions, it is likely that earthquakes will strike farms in operation. A practical approach to predict the dynamic behavior of a wind turbine under simultaneous seismic and operational wind loads is investigated in this work. The combined action can be determined by analyzing the wind and the seismic-induced responses separately. However, an accurate definition of the aerodynamic damping is required for this purpose and there are few experimental studies on the additional damping source. A 1/100-scaled wind turbine model was designed and the aerodynamic damping of the model was identified. Subsequently, the ground motion was applied in the model by means of a shake table and the combined wind/earthquake response that was measured experimentally was compared with the response predicted by several combination rules. A numerical study using the FAST analysis package for wind turbines was also conducted to complement the experiments with fully-coupled simulations that include aeroelastic effects. This work provides a necessary experimental reference for structural engineers to use adequate aerodynamic damping and load combination methods for the seismic analysis of wind turbines in operation. (c) 2020 Elsevier Ltd. All rights reserved.