Performance of periodically distributed resonators for vibration mitigation In wind turbine towers

Abstract

Context—Wind turbine towers are slender, flexible structures that are inherently susceptible to low-frequency vibrations induced by aerodynamic loading and rotor-related excitations. In particular, the overlap between structural natural frequencies and operational excitation ranges, such as 1P and 3P frequencies, may lead to resonance conditions that accelerate fatigue damage and reduce structural stability. Conventional vibration mitigation strategies, including tuned mass dampers (TMDs), are typically effective over a narrow frequency band and require precise tuning, which limits their robustness under varying operational conditions.Objective—In recent research, a metamaterial-inspired vibration mitigation approach based on the periodically distributed resonator idea has been investigated for the wind turbine towers with the specific emphasis on the mass ratio, tuning ratio and damping-related parameters.Method—The tower is modelled as a Euler-Bernoulli beam with a lumped nacelle mass, and the system is analyzed using a finite element formulation. Locally attached resonators are presented as mass-spring-damper systems and distributed along the tower height. A comprehensive parametric study is conducted to evaluate the influence of key design parameters, including the resonator tuning ratio, mass ratio, damping ratio, and the number of resonators. The dynamic response of the coupled system is assessed using frequency response function (FRF) within the operational frequency range of 0.1-1.5 Hz.Results—The results indicate that vibration attenuation is primarily governed by the frequency tuning of the resonators relative to the fundamental bending mode of the tower. The near-resonant configurations lead to increased interaction and partial suppression of the primary response peak. On the other hand, the off-tuned configurations contribute smoother response characteristics with limited direct influence on the dominant mode (around 3P). Increasing the resonator mass ratio enhances the interaction level; however, the overall attenuation remains constrained. Across all examined configurations, the observed peak reduction generally remains below 5%, indicating weak-to-moderate coupling between the resonators and the primary structure. The influence of damping is shown to introduce a trade-off between peak suppression and response stability, while increasing the number of resonators promotes more distributed interaction but does not significantly alter the magnitude of attenuation. The results further show that the system does not exhibit a distinct band gap, but rather a localized attenuation region.Conclusion—The proposed configuration is more appropriately interpreted as a distributed resonator system with metamaterial-inspired characteristics rather than a fully developed metamaterial structure. Overall, the findings provide a systematic assessment of a resonator-based vibration mitigation for wind turbine towers and highlight the limitations and potential of such systems for low-frequency vibration control in large-scale structures.