Nonlinear Wave Loads on Offshore Wind Turbines: Extreme Statistics and Fatigue

Abstract

The development is presented of an analytical model for the prediction of the stochastic nonlinear wave loads on the support structure of bottom-mounted and floating offshore wind turbines. Explicit expressions are derived for the time-domain and frequency-domain nonlinear exciting forces in a seastate with a significant wave height comparable to the diameter of the support structure based on the fluid impulse theory. The higher-order moments of the nonlinear load are evaluated from simulated force records, and the derivation of analytical expressions for the nonlinear load statistics for their efficient use in design is addressed.