Vibration analysis based on time-frequency analysis with a digital filter: Application to nonlinear system identification

摘要

The main purpose of this study is to model and identify the mechanical systems from their output signals of vibrations. The time-frequency analysis method based on infinite impulse response (IIR) digital filter technology is applied to identify nonlinear vibrations. In our previous research, the advantage of the time-frequency analysis procedure over FFT analysis was shown. Here, as a typical weakly nonlinear system, we discuss the time-frequency analysis of the Duffing equation. The time-frequency analysis results and the appropriate analytical solution are compared at steady state. Then, the numerical solutions of the Duffing equation for transient and non-stationary states, including passage through resonance phenomena, are examined with the use of the time-frequency analysis. Furthermore, the basic concept for an application to nonlinear system identification by the time-frequency analysis is discussed.