Avaliação do comportamento de turbinas eólicas offshore fixas do tipo Monopile

Abstract

Following a worldwide trend of moving the wind turbines from land to sea, this work inserts standard models used by the academy of 5 and 10MW wind turbines in the Brazilian environment being supported by fixed foundations of the monopile type. After validated through analyzes of the natural frequencies and the aerodynamic loads experienced by the structure, the models built in the SIMA-RIFLEX software are subjected to extreme loads of wind, wave and current to determine a critical point in the foundation, where a sensitivity study of the damage due to fatigue is planned to be done. For this study, cases in which the waves of the sea are represented by either the Jonswap or the Pierson-Moskowitz spectrum and for a wind with or without a dynamic component are created. Fatigue was assessed through the damage calculated by the Palmgren-Miner rule in association with the S-N curves provided by DNV and the rainflow counting method for the extraction of the requesting cycles from stress time series. The damage sensitivity study showed the importance of the dynamic component of the wind in the structure’s lifetime, which was reduced by at least one order of magnitude when considered. In addition, the 10 MW turbine delivered better life results than the 5 MW thanks to its more robust geometric characteristics.