Shaking table test and simulation study on CS-NES vibration control of offshore wind turbine

Based on the vibration response characteristics of monopile OWTs (Offshore Wind Turbines), this study investigates the feasibility of employing NES (Nonlinear Energy Sinks) for vibration reduction through a combination of experimental tests and numerical simulations. A CS (Conical Spring)-NES device with nonlinear stiffness is designed using conical springs, and its dynamic performance and vibration control effects are validated through shaking table tests. A numerical prototype-model of a 6.45 MW OWT prototype is established to compare the vibration control of NES and a linear TMD (Tuned Mass Damper). The results indicate that the CS-NES is capable of activating the SMR (Strongly Modulated Responses), exhibiting excellent robustness even under conditions such as stiffness errors and compression asymmetry, and significantly improving the OWT stability under various excitation scenarios. Compared to TMD, NES demonstrates superior performance in frequency band tuning and high-order frequency response control, particularly in controlling the response around resonant-frequency. This study provides valuable theoretical insights and practical guidance for nonlinear vibration control of OWTs. • Theoretical research. CS-NES is designed to verify its SMR mechanism, robustness, and energy dissipation based on nonlinear stiffness. • Shaking table test. The applicability of CS-NES under harmonic, seismic, and wind-wave excitations is verified via shaking table tests. • Numerical simulation. Comparative analysis shows NES outperforms linear TMD in wide-band tuning, peak attenuation, and high-order response control.