Real-time hybrid simulation of full-scale tuned mass-damper-inerter for vibration mitigation of floating offshore wind turbines under combined wind and wave loads

Experimental evaluation and validation of vibration mitigation of floating offshore wind turbines (FOWTs) face challenges due to laboratory limitations and scaling issues such as the inherent conflict between Reynolds and Froude similarity criteria, as well as the inherent nonlinearities associated with reduced-scale physical models and control devices. To address these challenges, a real-time hybrid simulation of full-scale tuned mass-damper-inerter (TMDI) for vibration mitigation of FOWTs under combined wind and wave loads is conducted in this study. By proposing a model decoupling and order-reduction method, a simplified numerical substructure is developed based on the theoretical model of FOWT-TMDI system, effectively reducing the computational burden in the hybrid simulation. The full-scale TMDI is assembled as the physical substructure. A real-time hybrid simulation system is then built by interacting numerical and physical substructures via OpenSees-OpenFresco-MTS actuators. Furthermore, through optimizing the actuator loading step size, strict real-time testing conditions are achieved. Experimental results considering multiple environmental load cases show a good agreement with numerical simulations by the theoretical model of FOWT-TMDI system; meanwhile, the TMDI can achieve FOWT tower’s response reduction of approximately 30%, validating the effectiveness of the TMDI for vibration mitigation of FOWTs under combined wind and wave loads.