Global Performance and Structural Digital Twins for a Floating Offshore Wind Turbine

Abstract The design and maintenance of Floating Offshore Wind Turbine (FOWT) platforms demand accurate global performance and structural analysis. Traditional frequency domain approaches fall short due to strong non-linear coupling among the turbine, tower, and substructure. Time domain analysis offers superior accuracy but requires significant time and computational resources. This paper introduces novel response-based time-domain global performance and structural analysis methodologies for digital twin applications. The approach involves using Finite Element Analysis to derive stress transfer functions for various load components, including wave, wind, current, mooring, cable, turbine operating, and floater motion-induced loads. Load components are synthesized with environment and platform responses, and total stress time history is processed at each location. This methodology enables efficient calculation of structural strength, consumed fatigue life, and prediction of remaining fatigue life. The approach allows for simulation of the entire service life responses of a FOWT during the design phase and creation of digital twins. Comprehensive prediction analysis during the design phase accurately estimates structural strength, fatigue life, and critical locations under various load cases. Real-time strength and fatigue analyses during the operating phase using digital twin models can be compared with predicted results, providing quick structural strength and fatigue damage assessments. The present methodology considers all non-linear loads without simplification, ensuring a comprehensive load mapping and synthesizing of stresses. This approach contributes to the efficiency and accuracy of digital twin models and asset integrity applications for FOWT. The presented method serves as a valuable tool for both new design and ongoing monitoring, offering quick and precise structural strength and fatigue assessments.