Using a two-stage approach to improving accuracy of resonance fatigue tests for large-scale wind turbine blades.

The increasing size and complexity of wind turbine blade designs challenge the ability of traditional fatigue testing methods to accurately and efficiently reproduce load distributions representative of real world conditions. A new two-stage approach is proposed. In the first stage, the blade is subjected to a dual-axis resonance test, where additional masses are mounted to the blade to control the bending moment distribution. In the second stage, part of the blade is removed, allowing it to be exercised at a higher frequency and for more damage to be applied to the root and transitional sections. The results of the proposed method were compared with those of traditional testing methods for 38 m and 60 m blades. The results indicate that the new methods have the potential to significantly improve accuracy, but the testing duration will increase. [ABSTRACT FROM AUTHOR]