Dynamic response of a horizontal axis wind turbine blade under aerodynamic, gravity and gyroscopic effects

Abstract

This work presents analytical and numerical dynamics studies of a horizontal axis wind turbine blade subjected to aerodynamic, centrifugal, gravity, and gyroscopic loads. The blade, assimilated to a long beam of variable cross section, is composed of homogeneous and isotropic material. It is discretized with blade elements of constant sections. Using Finite Element Method (FEM), the assembly of these elements constitutes an approximate model of the blade. The analytical study consists on defining the elementary matrices of rigidity, mass, and gyroscopic coupling between vibration and the blade rotation, as well as the elementary vector of the external loads. The numerical study deals with the resolution of the linear system of equations of the blade motion. Then, it will be possible to calculate its static and dynamic responses for a practical case. The numerical results show that the blade presents cyclic deformations under the considered loadings. These sustained vibrations directly affect the fatigue life of the blade, leading to a significant reduction in the operational efficiency of the wind turbine.