FLUTTER MARGIN PREDICTION BY COMBINATION OF RANDOM DECREMENT METHOD AND EIGEN-SYSTEM REALIZATION ALGORITHM

摘要

In order to find the aeroelasticity instability in flutter tests, the research to predict flutter margin has been conducted in JAXA. As the way to predict the flutter margin, the Random Decrement (RD) method was applied. Although the RD is useful for calculating the system damping, it was used in this study as the tool to acquire the quasi-step response of the system. This response, therefore, expresses a good combination with the Eigen-system Realization Algorithm (ERA). After the system model was identified by the ERA, the Discrete Flutter Margin was calculated. This series of processes was applied to the result of wind tunnel flutter test, and the influences of processing parameters were inspected. As the results of this study, the threshold level of RD processing does not influence seriously the results. On the other hand, the column number of Hankel matrix processed in the ERA influences the accuracy of flutter prediction.