Passive mitigation of nacelle vibration in tension leg platform floating offshore wind turbines through an inerter-enhanced damper: experimental investigation

Tension leg platform floating wind turbines (TLP-FWTs) have garnered increasing attention in the offshore wind industry due to their exceptional typhoon resistance and cost-effectiveness. However, owing to their significant structural flexibility and harsh service environments, mitigating nacelle acceleration has become a critical design consideration to ensure operational reliability. This study proposes a novel passive control strategy utilizing a tuned mass damper inerter (TMDI) to suppress nacelle vibrations in TLP-FWTs. The unique inertial amplification characteristics of the TMDI provide superior low-frequency vibration control capabilities with a relatively small physical mass, making it particularly suitable for TLP-FWTs with stringent tower-top mass constraints. To validate its control mechanism, a physical realization of a ball-screw type TMDI is developed. Based on a shaker testing, the inertance and amplification factor of the TMDI are identified. Furthermore, an integrated floating wind turbine-TMDI experimental system is established in a wave basin, where realistic environmental loads, including coupled wind, wave, and current effects, are physically reproduced. For the first time, the effectiveness of TMDI for nacelle vibration mitigation is experimentally evaluated through wave-basin model tests of a floating wind turbine, with a comparative assessment against a conventional tuned mass damper. The results show that the TMDI demonstrates superior low-frequency vibration control capabilities, effectively reducing the standard deviation of nacelle acceleration by 14.65%, outperforming traditional absorber in vibration control performance.