A comprehensive method for the structural design and verification of the INNWIND 10MW tri-spar floater

The present paper presents a comprehensive method for the structural design and verification of a floater, accounting for both ultimate limit state (ULS) and fatigue limit state (FLS). Three software are properly combined, a 3D Finite Element Method (FEM) solver, a coupled time domain hydro-servo-aero-elastic tool and a frequency domain hydrodynamic solver. The detailed analysis is performed in the 3D FEM solver through static load cases for ULS and frequency domain stochastic analysis for FLS, while the other tools provide the environmental excitation. The method is used for the detailed design and verification of the INNWIND 10MW tri-spar concrete floater that is assessed in terms of capacity ratios (for ULS) and damage ratios (for FLS), estimated at the most critical connecting positions. (paper)