Optimal design of a tuned rotational inertial damper for mitigating torsional vibrations in offshore floating wind turbine drivetrains

The expansion of offshore floating wind turbines (OFWTs) into deeper waters exposes drivetrain systems to harsher environmental excitations and stronger platform-shaft couplings. Under these conditions, mitigating torsional drivetrain vibrations becomes essential to reducing operational stresses and preventing costly failures. This study integrates a tuned rotational inertia damper (TRID), inspired by passive tuned mass damper principles, into a coupled aero-hydro-elastic-servo model for the OC3-Hywind spar-type OFWT to control the drivetrain torsional loads. The TRID’s performance is evaluated across different installation positions, inertia ratios, and empirical formulas, while robustness is further assessed under both diverse wind and wave conditions and wind and wave misalignment scenarios. The results reveal that installing the TRID near the generator, where torsional energy is concentrated, achieves optimal vibration reduction. An inertia ratio of approximately 2% proves most effective overall, enhancing damping in high- and intermediate-speed stages, while higher ratios offer stability benefits in the low-speed stage. The study on different formulas indicates that, compared to the gear loads in the low-speed and intermediate-speed stages, the high-speed stage gear loads are more sensitive to adjustments in TRID parameters. Furthermore, the TRID consistently exhibits robust suppression under both diverse wind and wave conditions and wind and wave misalignment scenarios. Near rated wind speeds, it achieves the most notable load reductions. Under large wind and wave misalignment angles, the mitigation effect becomes more pronounced. These findings emphasize the need to optimize TRID design configurations, including installation position, inertia ratio, and tuning frequency, to improve drivetrain durability and vibration control in OFWTs. The demonstrated robustness in complex offshore conditions indicates its potential to lower maintenance demands, enhance cost efficiency, and support future application in floating wind turbines.