Estimation of the frequency response of a structure using its non-stationary vibration

The frequency distribution of a short-interval period, the SIP distribution, obtained from the vibration of a structure that is excited by the force of non-stationary vibration, reflects the dynamic property of the structure. This idea was validated by numerical experiments and it was shown that the SIP distribution was fairly stable and accurate in comparison with the FFT spectrum for random noise excitation. A theoretical study is shown to confirm the idea.