Analysis of friction-induced vibration in a propeller-shaft system with consideration of bearing-shaft friction

This paper is concerned with friction-induced vibration of a continuous propeller-shaft system excited by nonlinear friction due to contact between a water-lubricated bearing and a shaft. The dynamic equation is derived using Hamilton's principle in conjunction with the finite element method. The drooping characteristics of the nonlinear friction and the torsional-lateral coupling via the bearing-shaft interaction laws are considered. Both stability analysis and responses analysis are then investigated through various system parameters. Stability is analyzed by determining the eigenvalues of the Jacobian matrix of the linearized system at the equilibrium point. Dynamic responses of the system are calculated on the basis of a reduced order modal model using the numerical integration method in order to validate the stability analysis. Numerical simulation proved to be consistent with the linear stability analysis. Analytical and numerical investigations reveal that friction-induced vibration of the proposed system is due to the combined action of nonlinear friction and coupled dynamics of the system, rather than the velocity-dependent friction alone as is commonly assumed.