FLOAT: Fatigue-aware design optimization of Floating Offshore Wind Turbine towers

Upscaling reduces offshore wind costs by enabling larger rotors and nacelles that require taller and stronger towers. In Floating Offshore Wind Turbines (FOWTs), this amplifies fatigue loads due to coupled wind–wave dynamics and platform motion. Conventional fatigue evaluation requires millions of high-fidelity simulations, creating prohibitive computational costs. This paper presents FLOAT (Fatigue-aware Lightweight Optimization and Analysis for Towers), an approach to accelerate fatigue-aware tower design. It integrates a lightweight fatigue estimator for efficient optimization, a probabilistic wind–wave sampler that reduces the number of simulations, and enhanced high-fidelity simulations enabled by pitch/heave–platform calibration and high-performance computing. FLOAT is demonstrated on the IEA 22 MW FOWT tower, delivering, to the authors’ knowledge, the first fatigue-oriented redesign of this model. 1 Validation against 6468 simulations shows that the optimized tower extends fatigue life from ∼ 9 months to 25 years while avoiding resonance, with the fatigue estimator achieving a mean relative error of − 8 . 6 %. This improvement requires increased tower mass, yielding the lowest-mass fatigue-compliant design. All results are obtained within the considered fatigue scope: DLC 1.2 under aligned wind–wave conditions for the selected site distributions. FLOAT enables reliable and scalable tower design in next-generation FOWTs, generating high-fidelity datasets for data-driven and AI-assisted design methodologies.