EXPERIMENTAL NONLINEAR MODELING OF A ROTATING MACHINE WITH AN OIL FILM BEARING

In this study the system identification method is applied to obtain a nonlinear equation for an oil film rotating system. The centrifugal force induced by an unbalanced mass is used as the input signal for identification, and the phase between the input signal and the mea-sured output vibration amplitude is calculated to perform the identification. Stability analysis and system performance are evalu-ated by using the root locus and the Floquet-Liapunov theorem. Based on the model, the oil whirl of the journal bearing can be predicted. A comparison between the simulation results and some experimented data shows the feasibility of the proposed approach