APPLICATION OF TIME-FREQUENCY ANALYSIS TO COUPLING FAULTS WITH OIL-FILM INSTABILITY AND PARTIAL RUB-IMPACT

A model test rig was set up to simulate coupling faults with oil-film instability and partial rub-impact.The collected vibration signals were roughly analyzed by 3-D waterfall spectra.In complicated frequency components domain,wavelet scalogram and reassigned wavelet scalogram were used to further analyze vibration signals.Results show that reassigned wavelet scalogram has higher time-frequency resolution than wavelet scalogram and can well identify such close low-frequency components.The analysis results also indicate rub-impact faults induced by oil-film instability can produce some low-frequency components with small amplitude and oil whip can produce half frequency component;rub-impact with a common extent exerts a light influence on rotor systems and nonlinear oil-film force plays a decisive role in rotor systems.