Numerical simulation of floating offshore wind turbines under environmental and seismic loading

Advancements in floating wind turbine (FOWT) technology—spanning spar-buoy, semisubmersible, and tension-leg platform (TLP) designs—have enabled deep-water deployment, including in seismically active zones near subduction boundaries. This raises the need for robust seismic assessment. Existing numerical tools often neglect soil–fluid–structure interaction, as most Computational Fluid Dynamics (CFD) platforms lack integrated soil modelling. This study presents a simplified Finite Element (FE) framework combining aero-hydrodynamic load modelling with seismic excitation using continuum-based soil models in Abaqus. Mode shapes for all six bending modes are estimated and validated with reported values in literature. Seismic responses of spar, semisubmersible, and TLP platforms are also compared. The validated framework provides a computationally efficient approach for evaluating FOWT behaviour under combined environmental and seismic loading conditions.