Evaluation of Structural Failure of Floating Offshore Wind Turbines Based on Return Periods of Wind, Waves and Earthquakes

This study presents a structural failure evaluation method for pontoon-type floating offshore wind turbines based on the return period of wind, wave, and earthquake actions. The response of the structures was evaluated using stationary random vibration theory and wet-mode superposition. Response analyses of the structures were also performed separately for each action because the wind, wave and seismic forces are independent. Structural failure is assessed using the response analysis results, and the failure probability is analyzed using the first-order reliability method. Numerical examples show the variation in failure probability owing to wind speed, earthquake scale in each return period.