Elimination of friction-induced vibration of a propulsion shafting system by auxiliary electromagnetic suspension

This paper focuses on the problem of eliminating self-excited vibration in a propulsion shafting system induced by the friction of the water-lubricated rubber bearing. A new scenario involving electromagnetic suspension is proposed to change the condition of instability. To explore the mechanism of elimination of self-excited vibration, a dynamic model of the shafting system is established on the basis of Hamilton's principle, the velocity-dependent friction model as well as the dynamics of the electromagnetic suspension. Influence of the electromagnetic force on the self-excited vibration of the system is evaluated. Transient responses of the system are obtained by using the Runge-Kutta fourth-order method. Numerical results indicate that the electromagnetic force can reduce the load on the rubber bearing and correspondingly the friction force on the interface. The occurrence of self-excited vibration will be delayed as the electromagnetic force increases, and once the suspension force increases to a critical value, instability of the system will be eliminated and vibration responses are damped exponentially.