Analysis of structural vibrations of vertical axis wind turbine blades via hamilton's principle-part 3: Pitch angle and equilibrium state
Journal
International Journal of Structural Stability and Dynamics
Journal Volume
21
Journal Issue
5
Date Issued
2021
Author(s)
Abstract
Pitch angle is one of the most important parameters of wind turbine blade. This study is aimed to investigate the effect of the pitch angle on the deformation of a VAWT. Lagrangian mechanics and Euler's beam theory are used to derive the motion equations of linear structural vibration for straight blade vertical axis wind turbine blade with the pitch angle α. The complete equations of motion take account of the 4-DOF deformation of flexural-flexural-Torsion-extension as well as the material damping. Vibration analysis of generalized displacement about the equilibrium state (GDAES) is carried out with respect to the displacement of the equilibrium state (DOES), which is separated from the motion of vibration. After simplifying the equilibrium equation of 4-DOF into 1-DOF system, the exact solution of displacement u1E of the equilibrium state is derived. The correction I"ω(α) of maxu1E due to the pitch angle and the characteristics of maxu1E with constant linear speed are analyzed. Furthermore, we investigate the coupling effect of lateral bending and axial extension of the blade on maxu1E is analyzed. Finally, the exact solution of maxu1E is verified by the central difference method. ? 2021 World Scientific Publishing Company.
Subjects
Deformation; Equations of motion; Structural dynamics; Turbine components; Vibration analysis; Wind turbines; Central difference method; Equilibrium equation; Euler's beam theory; Generalized displacements; Hamilton's principle; Lagrangian mechanics; Structural vibrations; Vertical axis wind turbines; Turbomachine blades
SDGs
Type
journal article