Markov approach to estimate fatigue damage for monopile-based offshore wind turbines

Abstract

The Markov approach to estimate fatigue damage for a monopile-based offshore wind turbine exposed to aerodynamic and hydrodynamic loading is investigated in this study. The focus of this study is on obtaining the rainflow-counting intensity from a peak-trough counting using the Markov method proposed by Frendahl & Rychlik. The fatigue damage estimated from the rainflow-counting intensity is compared to fatigue damage estimated from the original time-series using the rainflow-counting algorithm. The comparison is performed for different load situations. The study shows that the Markov approach performs the best for load situations where wave loading is dominating the response, making it interesting for load calculations of large-diameter monopiles and monopiles in parked or idling conditions.