On the non-linear dynamic behavior of a rotor–bearing system

The non-linear dynamic behavior of a rotor–bearing system is analyzed based on a continuum model. The finite element method is adopted in the analysis. Emphasis is given on the so-called “oil whip phenomena” which might lead to the failure of the rotor system. The dynamic response of the system in an unbalanced condition is approached by the direct integration method and mode superposition method. It is found that a typical “oil whip phenomenon” is successfully produced. Furthermore, the bifurcation behavior of the oil whip phenomenon that is much concerned by present non-linear dynamics is analyzed. The rotor–bearing system is also examined by the simple discrete model. Significant differences are found between these two models. It is suggested that a careful examination should be made in modelling such non-linear dynamic behavior of the rotor system.