Hybrid vibration mitigation of jacket-supported 15 MW offshore wind turbines under multi-hazard excitations

This study evaluates hybrid vibration control for jacket-supported 15 MW offshore wind turbines under coupled wind–wave–seismic excitation using nonlinear finite-element time-domain analysis. Four configurations, namely the baseline system, viscous dampers, lead rubber bearings (LRBs), and a hybrid control scheme, are assessed under two soil conditions with shear wave velocities of approximately 150 and 300 ms −1 . Five recorded earthquake pairs representing near-field and far-field motions are considered. The hybrid configuration consistently delivers the greatest response reduction. Tower accelerations decrease by up to 97% in peak, satisfying the 2.943 ms - ² operational limit in stiff soil across all records. Peak lateral displacements are reduced by up to 35%, while rotational responses remain well below the 5° serviceability threshold, reaching approximately 0.02° about the X-axis and 2.7° about the Y-axis. Peak shear forces decline by 65∼80%, and bending moments by about 70%. Von Mises stresses at the tower top decrease by up to 75% in stiff soil, with comparable improvements observed in softer soil. Energy analysis further indicates a 20∼21% reduction in tower-level viscous dissipation for the LRB and hybrid systems. These results demonstrate that hybrid control provides a robust and scalable strategy for reducing multi-hazard seismic demand in offshore wind turbines.