关键词: 非线性系统, 径向轴承, 摩擦, 振动分析

Abstract: Unacceptable vibrations and noise induced by the water-lubricated bearing-shaft friction in propeller-shaft systems seriously affect the stealth performance of warships. To find out the basic excitation mechanism has important significance to the recognition and efficient control of the unwanted vibrations and noise. Friction-induced vibration in the propeller-shaft system is studied on the basis of the interactions between the nonlinear friction and the overall system dynamics. A nonlinear mathematical model by using the Hamilton’s principle in conjunction with the finite element method is formulated. The model accounts for the lateral-torsional vibrations interactions as well as the bearing-shaft friction represented by the Stribeck curve. A numerical method, which combines the Newmark-β method and the Newton-Raphson iterations, is used to obtain the system dynamic responses. Effects of the frictional characteristics and lateral-torsional interaction on the generation of the friction-induced vibration are analyzed. The results show that the coupling system is more prone to the onset of the instability compared with the pure torsional system. Besides the frictional characteristics, the instability of particular lateral modes is an important factor with regard to the occurrence of the friction-induced self-excited vibration.

Key words: Friction, Journal bearing, Nonlinear systems, Vibration analysis