Nonlinear vibrations of a rotor on nonlinear tilting-pad-journal-bearings

Abstract

In this paper, the coupled equations of nonlinear vibrations of a rigid two-dimensional rotor supported on tilting-pad-journal-bearing under harmonic excitation have been studied using second-order multiple scales method. By considering a nonlinear quadratic model for tilting-pad-journal-bearings, the governing coupled nonlinear differential equations of motion are presented. The frequency response function of the system, the effect of excitation force on the response, and stability of the system are discussed in different operating conditions using the method of multiple scales and validated with a numerical method. The results show that the system may have hardening or softening behavior under different working conditions because of the different nonlinear characteristics of the system. It is shown that the solution may be multivalued depending on initial conditions; also, jump phenomena can be observed.