Effects of second-order wave force on fatigue damage assessment of a tlp-type floating wind turbine

Paper in proceeding, 2020

Resonant and transient responses of a tension leg platform (TLP)-type floating offshore wind turbine can be excited by high-frequency wave forces. This paper investigates the damaging effect of second-order wave forces on structural fatigue in the WindStar TLP system. Dynamic responses in the time domain are analyzed using the program FAST. To explore the mechanisms of different combinations of wind and wave loads inducing damage, five scenarios are considered: wind only, first-order wave only, second-order wave only, joint wind and first-order wave, and joint wind and second-order wave. The results show the dominant effect of second-order waves in tower structural fatigue damage. Additionally, wind and wave coupling becomes stronger under second-order wave loads.