Multiple tuned mass damper for multi-mode vibration reduction of offshore wind turbine under seismic excitation

With the wide spreads of the wind energy production industry, the demand for the safe and feasible design of wind turbine structures is growing swiftly. The magnificent deployment of wind turbines in hostile environments with high seismic hazard, has lead engineers to consider more comprehensive way of seismic design, and control technics of a gigantic structure like jacket supported offshore wind turbine (OWT). The current research provides an overview to alleviate the dynamic structural responses of the jacket supported OWT due to the seismic loads associated with static wind and wave loads. Multiple tuned mass damper (MTMD) has been installed at the top and base of the turbine tower corresponding to the mode shapes of the structure. The MTMD parameters have been optimized based on response surface methodology (RSM). The performance of MTMD following the multi-mode control strategy seems to be prominent in suppressing the first two vibrational modes. To evaluate the proposed strategy, frequency response function (FRF), fast Fourier transforms (FFT), peak and lateral displacements of the tower, root mean square (RMS), shear and moment have been investigated through the uncontrolled and controlled structures. In addition, the practicability of the MTMD system is also compared with the single tuned mass damper (STMD).