A Novel FPB-based Isolation Method at Tower–Nacelle Interface for Seismic Performance Enhancement of Onshore Wind Turbines

Dynamic behaviors of wind turbines can be significantly amplified when they are exposed to seismic and wind loads. To mitigate dynamic responses and enhance structural stability, friction pendulum bearings (FPBs) are introduced to isolate the nacelle from the tower in this work. The reduction performance of FPB on nacelle acceleration response, tower displacement response, and foundation reaction forces is investigated based on finite element analysis; meanwhile, the overturning resistance capacity of the isolated nacelle is also evaluated. Parametric studies are carried out to assess the impacts of the friction coefficient, equivalent radius of FPB, and peak ground acceleration (PGA) on FPB’s isolation effectiveness. The results demonstrate that FPB shows significant reductions in the peak and root mean square (RMS) values of nacelle acceleration and tower displacement responses. Furthermore, the structural reaction forces, including base shear and bending moment of the wind turbines, are mitigated by FPB while maintaining the overturning resistance capacity of the isolated nacelle. Parametric studies indicate that superior isolation performance can be achieved by reducing the friction coefficients of FPB through larger sliding displacements. Additionally, higher PGA values will enhance the operational efficiency of FPB, thus improving its isolation effectiveness.