Extreme value characteristics of jacket-type offshore wind turbine dynamic response under wind-wave actions

Jacket-type offshore wind turbine (JOWT) operates in a marine environment where wind and wave interact. The dynamic characteristics of JOWT are significantly affected by the wind-wave coupling effect. To study the extreme value characteristics of structural responses, this research conducted scaled experiments on the 10 MW JOWT. The extreme value distribution of combined loads was constructed, and the environmental load factors were calculated for different reliability indices. The research results reveal that the tower top displacement and foundation shear exhibit distinct wind-wave coupling characteristics. For the tower top displacement, the maximum wave load combination factor is below 0.3. Wind load is the dominant load of the tower top displacement. The foundation shear is significantly influenced by wave load and should be divided into wind-dominated and wave-dominated zones for load combination design. The extreme value distribution of the combined load is significantly influenced by the wind and wave load correlation. As the correlation coefficient increases, the peak of the extreme value distribution of combined loads decreases while the distribution range expands. The environmental load factors are significantly influenced by wind-wave coupling effects. Compared to wind-only conditions, the environmental load factors significantly increase under wind-wave coupling effects.