Influence of Trailing-Edge Wear on the Vibrational Behavior of Wind Turbine Blades

To study the impact of the trailing-edge wear on the vibrational behavior of wind-turbine blades, unworn blades and trailing-edge worn blades have been assessed through relevant modal tests. According to these experiments, the natural frequencies of trailing-edge worn blades -1, -2, and -3 increase the most in the second to fourth order, the fifth order increases in the middle, and the first order increases the least. The damping ratio data indicate that, in general, the first five-order damping ratios of trailing-edge worn blades -1 and trailing-edge worn blades -2 are reduced, and the first five-order damping ratios of trailing-edge worn blades -3 are slightly improved. The mode shape diagram shows that the trailing-edge worn blades -1 and -2 have a large swing in the tip and the blade, whereas the second- and third-order vibration shapes of the trailing edge-worn blade -3 tend to be improved. Overall, all these results reveal that the blade's mass and the wear area are the main factors affecting the vibration characteristics of wind turbine blades.