Study On Dynamic Characteristics Of Large Offshore Wind Turbine Structure System

The environment and energy problems are the issues in the world. The fossil fuel is exhausting and imposes great impact on environment. More and more countries all over the world are focusing on exploitation of renewable energy, especially wind energy. Offshore wind turbine structures are installed in severe marine environment and suffered from variety random loads such as wind, waves, sea ice and earthquake. Offshore wind turbine structures are constituted of blade, turbine, tower and foundation, which vibration characteristics are very complex. Therefore, it is of significance to study on dynamic characteristics of offshore wind turbine structures and ensure safety of them.The study on the dynamic characteristics for a 1.5MW offshore wind turbine is carried out. The main contents are as the following:Firstly, the basic theories about offshore wind turbines are introduced. Based on the theory of aerodynamics of wind turbines, the aerodynamic characteristics of the blade of wind turbine are summarized, and several optimal design models for wind turbine blade are introduced.Then, based on ANSYS parametric design language (APDL), the module of the geometry modeling of the wind turbine blades is developed. Therefore, the blade model of offshore wind turbine with complex shape is established. The finite element models of the wind turbine components such as a blade, and plus rotor and engine are built, respectively. Meanwhile, considering the pile and soil interaction, an integral structure model of offshore wind turbine including blade, rotor, tower and pile are established.Finally, the dynamic characteristics of the rotor and engine and total structures including tower and foundation of a large offshore wind turbine are respectively calculated. Therefore, the frequencies and mode shapes of components and integral structure are obtained. The effect of dynamic characteristics and environmental loads on dynamic response of the offshore wind turbine structure is studied.The study on dynamic characteristics of large offshore wind turbine structure system supply a theoretical basis for preventing the offshore wind turbines from resonance and increasing their operating life.