• Yangui, Majdi
• Bouaziz, Slim
• Taktak, Mohamed
• Haddar, Mohamed
• Debut, Vincent
• Antunes, Jose

Abstract

<p>The vibration behavior of wind turbine blades (WTB) must be thoroughly investigated to avert undesirable dynamical phenomena under working conditions. This paper sets out an experimental frequency analysis of a rotating, scaled-down, segmented WTB. The purpose of the present work is twofold: (1) to devise a suitable experiment for the modal identification of a rotating component, when no rotor-specific test equipment is available, and (2) to validate a recently developed theoretical model for the dynamics of segmented wind turbine blades, through the modal parameters of the test blade identified for a given range of spinning velocity. The 3D fused deposition modeling technology was used to manufacture the blades segments, assembled with a steel threaded shaft and nut. A speed-controlled motor is used to scrutinize the influence of the rotation velocity on the blades modal parameters. To identify the blades modal frequencies and damping ratios, the eigensystem realization algorithm method was implemented. At rest, the blades natural frequencies were adjusted based on the additional assembly stiffness generated by the nut tightening torque. Because the modal identification of rotating components using conventional test equipment is a difficult task, a significant feature in this paper, beyond the obtained results, is the proposed original experimental technique to investigate the flapwise (out-of-plane) dynamical behavior of the rotating blades. The experimental results are compared with previous theoretical results, as a function of the blades spinning velocity, showing the significant influence of the rotation speed on the segmented WTB dynamical behavior, in agreement with the theoretical predictions.</p>

Topics

• Deposition
• impedance spectroscopy
• experiment
• steel
• spinning