Jul 2026· International Journal of Structural Stability and Dynamics· 0 citations
Abstract
Offshore wind turbine (OWT) towers are continuously subjected to highly variable wind-wave excitations, where structural parameter uncertainties arising from manufacturing tolerances and material heterogeneity may significantly degrade vibration control performance. Conventional tuned mass dampers (TMDs), particularly single-TMD configurations, are highly sensitive to detuning effects and thus lack robustness under uncertain operating conditions. This study proposes a robust optimization framework for vibration mitigation of offshore wind turbine towers using multiple tuned mass dampers (MTMDs). Structural parameter uncertainties in total mass and stiffness are explicitly considered through Latin hypercube sampling (LHS), enabling a sample-based evaluation of control performance. Inverse Element Exchange Method with Multi-level Programming (MulIEEM) is applied to determine the optimal distribution of damping coefficient, mass, and for the TMDs. Three objective functions are investigated, including minimization of the sample mean, sample standard deviation, and single-sample response, allowing a systematic assessment of vibration reduction effectiveness and robustness. Stochastic wind and wave loads are synthesized using the Kaimal wind spectrum and JONSWAP wave spectrum, while structural uncertainties are represented through Latin Hypercube Sampling (LHS). The statistical characteristics of the displacement responses across all samples are used to evaluate robustness and provide an indirect measure of sensitivity to uncertainty-induced detuning effects. Three objective functions are investigated, including minimization of the sample mean, sample standard deviation, and single-sample response, allowing a systematic assessment of vibration reduction effectiveness and robustness, defined herein as reduced sensitivity to structural uncertainties. Numerical results demonstrate that the proposed MulIEEM-based MTMD designs significantly reduce both the mean and variability of tower displacement responses across a wide range of wind speeds. Furthermore, single-sample-based optimization is shown to achieve a favorable balance between control effectiveness and computational efficiency. The proposed framework provides a practical and robust design strategy for vibration control of offshore wind turbine towers under structural uncertainty.
Tuned viscous mass dampers (TVMDs) are effective devices for wind-induced vibration control in supertall buildings, but their performance depends on a precise resonance condition that can be disturbed by manufacturing tolerances. This study identifies an insufficiently examined asymmetric sensitivity mechanism, termed the “dangerous diagonal effect”, in which opposite-sign errors in TVMD inertance and stiffness amplify tuning-frequency drift and create a worst-case sensitivity space that conventional symmetric uncertainty models may underestimate. To tackle this challenge without requiring prior statistical distributions unavailable at the design stage, an Info-Gap Decision Theory (IGDT) robust optimization framework tailored to TVMDs under stochastic wind excitation is developed. A Kriging-metamodel-assisted Efficient Global Optimization bi-level strategy reduces the computational burden of the nested worst-case search. Applied to a 76-story, 306 m benchmark building under a dual-criterion constraint combining the ISO 10137 comfort limit and a 30% relative degradation bound, the framework certifies comfort compliance for manufacturing errors up to 23.44% along the dangerous-diagonal direction. Under the most severe coupled degradation scenario, which integrates opposite-sign manufacturing detuning, 50-year power-law aging, and Arrhenius thermal drift, the nominal H2-optimal design collapses to 36.7% vibration reduction efficiency while the IGDT robust design sustains 51.7%, reducing the Monte Carlo failure probability from 3.8% to 1.2% across 500 random realizations. An aeroelastic wind tunnel campaign spanning 620 detuning configurations on a 1:350 scaled model provides physical validation of IGDT design reliability for a TVMD system. The experiments corroborate the dangerous-diagonal sensitivity asymmetry, support the predicted robustness plateau under severe parameter detuning, and show that the IGDT framework maintains comfort compliance where the H2-optimal design fails.
A tuned mass damper (TMD) is one of the dominant technologies for vibration control in offshore wind turbines (OWT). However, the variation in their vibration mitigation performance across a range of typical load cases throughout the full service life of wind turbines remains to be comprehensively assessed. This paper investigates the vibration mitigation patterns of TMDs on the dynamic responses of OWTs across five typical operational and extreme load cases, namely cut-in wind speed, rated power operation, cut-out wind speed, and two categories of extreme wind conditions. The results demonstrate that TMDs do not exert significant control effects across all load cases and response indicators. Their vibration mitigation effect on nacelle acceleration is the most stable and prominent, with optimal performance achieved under the cut-out wind speed shutdown load case, where the peak fore-aft vibration mitigation rate can reach 60.0%. However, the vibration mitigation rate of tower top displacement under normal operating load cases is significantly lower than that under shutdown conditions; the peak fore-aft displacement mitigation rate under the rated wind speed load case is merely 7.8%. The fore-aft foundation reaction forces achieve limited mitigation from TMD control, with a slight negative vibration mitigation effect even observed under extreme wind conditions. The effect of frequency detuning exhibits pronounced directional heterogeneity. For the side-to-side direction, −20% detuning reduces the mitigation rate from 45.0% to 29.2%, while for the fore-aft direction, +10% detuning increases it from 58.2% to 72.6% under rated operating conditions.
Yingna Li, Jingcai Zhang, Hao Yang et al.· Journal of Marine Science an...· 0 citations
The tuned mass damper inerter (TMDI) is a passive vibration absorber that suppresses structural vibrations by leveraging the inertance property of inerter devices. Previous studies have demonstrated TMDI effectiveness in wind turbines, but relied on simplified structural models. To date, no study has implemented multi-directional TMDIs within aero-hydro-servo-elastic tools such as OpenFAST to enable independent vibration control across multiple turbine components, including the tower, blades, and substructure. This paper addresses this gap by implementing the TMDI in OpenFAST. The governing equations of motion are derived and implemented within the Structural Control (StC) Module, supporting arbitrary TMDI connectivity and independent multi-directional configurations across turbine components. Verification against independent numerical models confirms the implementation's accuracy across all supported configurations. An application study examines the IEA 15MW reference wind turbine equipped with a tower-top TMDI under combined wind-wave loading. Optimal tuning is performed using a simplified two-degree-of-freedom model, with modal properties extracted from an OpenSeesPy finite element model of the IEA 15MW. Results show that TMDIs with secondary mass up to 100 times smaller than a conventional TMD achieve matching or superior vibration suppression in the fore-aft and side-side directions, in terms of peak and standard deviation of tower-top displacement and acceleration. Notably, TMDI stroke is markedly reduced compared to the TMD, better suiting the spatially constrained wind turbine environment. These results support the practical merit of lightweight TMDIs for wind turbine vibration control, with the OpenFAST implementation enabling performance-driven design under realistic loading conditions.
Hisham Tariq, Yuan Li, F. Luca et al.· 0 citations
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.
Şifa Gül Demiryürek· Pamukkale Üniversitesi Mühen...· 0 citations
The tuned mass damper (TMD) exhibits good performance in suppressing wind-induced vibrations of high-rise structures. However, a single TMD has a limited control bandwidth and poor robustness. The multiple-pendulum tuned mass damper (MPTMD) offers advantages, such as a wider control bandwidth, stronger robustness, and a simple structural configuration, while its working frequency can be easily adjusted by varying the pendulum lengths. With two optimization objectives, namely displacement and acceleration, this study derives the displacement and acceleration dynamic amplification factors of the primary structure equipped with the MPTMD under external excitation and examines the interrelationships among the optimal parameters and their underlying mechanisms. The accuracy of the proposed optimization method and the effectiveness of the MPTMD are validated by fitting the theoretically derived optimal parameter curves with results from numerical simulations. Finally, the control performance of MPTMD and TMD is compared through a numerical example subjected to realistic wind load excitations, verifying the control effectiveness of MPTMD. Nevertheless, several limitations should be acknowledged. The present optimization is based on a single-degree-of-freedom (SDOF) primary structure and targets only the first translational mode; the effects of higher modes and multi-degree-of-freedom (MDOF) coupling are not considered. Additionally, the wind load is represented by a synthetic time history with a fixed return period, and uncertainties in real wind fields are not fully addressed. Future work should extend the proposed method to multi-modal control, nonlinear behavior, and experimental validation.
Han Wang, Zuohua Li, Dan Han et al.· CivilEng· 0 citations
Wind turbines in seismically active regions are increasingly vulnerable to earthquake-induced vibrations due to their growing height and flexibility. Effective vibration control is therefore essential to ensure structural safety and operational reliability. This study examines the performance of a novel compact nonlinear magnetic damper with non-contact restoring and damping force generation in mitigating the seismic response of wind turbine towers. The tower is modeled through a three-degree-of-freedom modal representation, corresponding to the first three fore–aft mode shapes obtained from a finite element–based modal analysis. A synthetic acceleration record was then developed by averaging the frequency content of five well-known earthquakes to represent their dynamic characteristics, providing a comprehensive excitation spectrum for evaluation. The damper parameters were optimized using a Bayesian optimization framework, with the root-mean-square of tower-top displacement adopted as the objective function. The optimized configuration was subsequently assessed under each individual earthquake record to evaluate its robustness. Results show that the proposed damper, together with the optimization scheme, achieves 36–65% reductions in RMS tower-top displacement and maintains consistent performance across different ground motions. The findings demonstrate the effectiveness and adaptability of the magnetic damper in enhancing the seismic resilience of wind turbine structures and provide a promising direction for integrating smart damping technologies into renewable energy systems.