RESEARCH ON ROTOR DYNAMICS WITH SUDDEN CHANGE OF MASS AND EXCITATION MAGNITUDE

Dynamical model and equation of Jeffcott rotor system with sudden change of mass and excitation magnitude were established based on rotor dynamics. Vibration expression of rotor system with these two synchronized suddenly changed parameters was obtained through analytical method. Relationship between the steady-state amplitudes fore and after parameters sudden change was analyzed, and the influence of suddenly changed parameters on maximal axial displacement was studied. Transient time duration after the sudden change of mass and excitation magnitude was defined and rubbing parameters region was determined. The conclusion indicates that sudden change of mass and excitation magnitude can cause the magnification of rotor vibration; flexible rotor systems with these two suddenly increased parameters have greater possibility of inducing rubbing; transient time duration increases with the increase of ratios of suddenly changed parameters; rubbing parameters region area increases rapidly with the enlarging of mass eccentricity, and etc.