Time-Frequency Domain Filtering And It's Application For Signal Processing Of Flutter Tests

Joint time-frequency distributions represent the energy or intensity of signal simultaneously in time and frequency. It's a problem of great significance how to filtering a signal in joint time-frequency domain and reconstruct the time series from the time-frequency plane selected. In this thesis, the theory of joint time-frequency analysis and synthesis and time-frequency filtering is investigated. Two kinds of new time-frequency domain filtering methods are proposed based on adaptive decomposition and linear subspace projection. The theory analysis and method principle are presented The characteristics of the two methods are studied by computer numerical simulation. The results show that both the methods are reasonable and feasible.Focused on the features and requirements of flutter test data processing, the methods presented here are used to pickup the major information as a pre-processing technique The application scheme is brought out for flutter boundary prediction based on subcritica. turbulence response. The functions of the methods are investigated by computer simulation and further examined by using flutter testing data of low-speed wind-turne of some aeroelastical modes.The related software is developed on Matlab and Labview for Windows.