• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1162-1169
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• 2010

The dynamic balancing of a rotor system is needed to alleviate the imbalances originating from various sources encountered during blade manufacturing processes and environmental factors. This work aims at developing a comprehensive analysis system which consists of cumulative module of test D/B and selection of optimal control parameters. This system can be used for the dynamic balancing of helicopter rotors based on tracking results from the whirl tower test. For simplicity of the analysis, a linear relation is assumed between the balancing input parameters and the blade track responses leading to influence coefficients and thereby the rotor system identification is made. In addition, the balancing parameters of the individual blades are sought using the genetic algorithm and the effectiveness of the proposed method is demonstrated in comparison with the test results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.7
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• pp.645-653
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• 2013

Seoul National University flap(SNUF) blade is a small-scale rotor blade incorporating a small trailing-edge flap control surface driven by piezoelectric actuators at higher harmonics for vibration attenuation. Initially, the blade was designed using two-dimensional cross-section analysis and geometrically exact one-dimensional beam analysis, and its material configuration was finalized. A flap-deflection angle of ${\pm}4^{\circ}$ was established as the criterion for enhanced vibration reduction based on an earlier simulation. The flap-linkage mechanism was designed and static bench tests were conducted for verifying the performance of the flap-actuation mechanism. Different versions of test beds were developed and tested with the designed flap and the selected APA 200M piezoelectric actuators. Through significant improvements, a maximum deflection of ${\pm}3.7^{\circ}$ was achieved. High-frequency experiments were conducted for evaluating the performance, and the transfer function of the test bed was determined experimentally. With the static tests almost complete, the rotor power required for testing the blade in a whirl tower (centrifugal environment) was calculated, and further preparations are underway.