Capability and Limitations of a Tuned Mass Damper for a 15‐MW Semisubmersible Floating Wind Turbine

ABSTRACT Large floating offshore wind turbines (FOWTs) under coupled aerodynamic and hydrodynamic loading exhibit broadband low‐frequency response in addition to the platform‐pitch resonance. Tuned mass dampers (TMDs) have been studied for a range of applications, but their net benefit under fully coupled operational conditions has not been quantified. This study uses a high‐fidelity OrcaFlex model of the IEA 15‐MW turbine on the VolturnUS‐S semisubmersible platform to characterise the baseline spectral response and assess the effects of a conventional nacelle‐mounted TMD. Results show that, under wave‐only parked conditions, the inclusion of the TMD reduces the pitch standard deviation by up to 30%. However, under turbulent wind–wave loading, the same device suppresses the pitch‐resonant peak but amplifies the subresonant response. This amplification is dominated by the TMD gravity‐coupling moment, which modifies the effective low‐frequency pitch response, explains about 63% of the ULF‐band variance increase and turns the net effect on pitch standard deviation into an increase. Even after gravity compensation, the required stroke exceeds the available nacelle clearance over most of the operational range. Overall, the TMD is useful mainly for narrow‐band resonant excitation.