A Parametric Study of Intervening Factors in Vibration Mitigation in Wind Towers Controlled by TLCDs

Resumo

Wind turbine support towers are tall and slender structures, because of this, they have low natural vibration frequencies, which make them susceptible to vibrations due to wind, earthquakes and/or other dynamic actions. These vibrations can cause sensory discomfort and structural damage, causing collapse by amplification of structural responses or the failure of some structural components due to fatigue. Therefore, it is interesting to implement vibration control devices to attenuate the vibrations. This work analyzes Tuned Liquid Column Dampers (TLCDs) as a passive structural control. The mathematical formulations of the wind tower motion equations are presented for structural systems with a single, and with several degrees of freedom, under bending effects, and for the incompressible fluid column (TLCD). Initially, the tower and TLCD systems are studied separately, and later in a coupled manner, within a wide range of parameter values, an aspect that allows the construction of response maps representing the ratio of attenuated and non-attenuated structural response. A simplified way of optimizing parameters of a TLCD model in the time and frequency domain under harmonic excitation is proposed to improve the performance of TLCDs, as well as simulations on wind towers with many degrees of freedom, dimensions, and real conditions.