Vibration Characteristics Analysis of the Rub- Impact Rotor System with Mass Unbalance

In this paper, vibration characteristics of a rub-impact Jeffcott rotor system excited by mass unbalance including the eccentric mass and the initial permanent deflection are investigated. Through the numerical calculation, rotating speeds, mass eccentricities, initial permanent deflections and phase angles between the eccentric mass direction and the rotor initial permanent deflection direction are used as control parameters to investigate their effect on the rub-impact rotor system with the help of bifurcation diagrams, Poincare maps, frequency spectrums and orbit maps. Result shows that these two kinds of mass unbalance have great but different effect on the dynamic characteristic of the rubbing rotor system. Different motion characteristics appear with the varying of these control parameters, and complicated motions such as periodic and quasi-periodic vibrations are observed. Corresponding results can be used to diagnose the rub-impact fault and decrease the effect of rub impact in the rotor system with mass unbalance.