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Non-linear dynamics of a rigid, unloaded andunbalanced rotor on lubricated bearings

Research paper by S. Pagano, M. Russo, R. Russo

Indexed on: 01 Sep '97Published on: 01 Sep '97Published in: Tribology Letters



Abstract

The dynamic behaviour and stability analysis of an unloaded rotoron cylindrical lubricated bearings subjected only to the actionof unbalance is presented. The ``short bearing model'' has beenadopted to evaluate the hydrodynamic fluid film force. As theunbalance increases, the system shows the typical behaviour ofnon-linear mechanical systems as the non-linearity of the hydrodynamic force field becomes more important. Evaluating theapproximate circular and centred analytical expressions of thetrajectory, the frequency response curves of the amplitude ofthe synchronous orbit have been reported. The stability limitcurve of the synchronous response has been obtained by means ofthe Floquet theory. Several examples of journal trajectories,obtained through step-by-step integration of the motionequations, are reported to illustrate the dynamic behaviour ofthe system and to verify the validity of the stability limitcurve.