Beschreibung:
Dynamic response analysis of wind turbine plays a pivotal role in their analysis, design, stability, performance and safety. To improve the calculation accuracy of natural frequency and dynamic response of megawatt wind turbine flexible components, a novel time-variant prediction model which can quickly and accurately calculate the unsteady load, modal characteristics and dynamic response of blade and tower is proposed. The hybrid beam theory considering shear deformation and centrifugal stiffening effect, and the generalized Lanczos algorithm are first applied in the model. Meanwhile, the model accounting for the dynamic inflow of the rotor, structural-damping and aerodynamic-damping of blade and tower, the structural coupling between blade and tower, unconditionally stable Wilson- implicit integration is used to solve the dynamic response. Compared to the public experimental data of NREL 5-MW offshore wind turbine, it is confirmed that the model in the manuscript is accurate, reliable and has high calculation accuracy. Furthermore, the time-variant dynamic responses of blade tip and tower top under normal turbulence model (NTM) and extreme coherent gust with direction change (ECD) are further analyzed. The prediction model can accurately calculate the unsteady dynamic load, natural frequency and nonlinear large deformation for megawatt flexible wind turbines under different operation conditions