Uncertainty Analysis in Fatigue Design of Offshore Wind Turbine Monopile Structures

Abstract

ABSTRACT: Importance of offshore wind energy production has grown in the last days. Various types of foundations can be used for offshore wind turbines, being monopile structures the most common solution. As a result, this project aims to describe the behavior of monopile structures respect to fatigue loads when including uncertainty. The fatigue design has considered damage equivalent loads (DEL) to obtain damages and probabilities of failure (POF). Monte Carlo method has been used for finding out the effect of the uncertainty of several parameters (natural frequency, damping ratio and sea state) in the POF of the structure. The results obtained show that natural frequency uncertainty decreases the POF of the structure, while damping ratio uncertainty increases it. The uncertainty in the sea states generation has an almost negligible effect on the POF when having a certain number of simulations performed respect to the use of a scatter diagram.