Analysis of Second Hydrodynamic Loads Effect on the Mooring Line Response and Damage Equivalent Fatigue by Wave Energy Components Under Extreme Sea Conditions

Abstract

In this study, we analyzed the effect of the second hydrodynamic loads on mooring line response and damage equivalent fatigue by wave energy components under the extreme sea conditions. To examine this effect, the dynamic responses of offshore wind turbine structures were evaluated by separating each component and coupling it with a HydroDyn module of the NREL FAST software. It was found that the wave energy affecting the mooring tension is larger in the swell than in the wind sea and thus creates larger mean position changes in the structure. In conclusion, the second hydrodynamic load influenced the behavior of the structure, which significantly affects the damage equivalent fatigue of the mooring line.