Self-sustained vibrations of one disk rotor in two arbitrary length journal bearings

•Journal forces are obtained from finite element calculations of power series.•Four-degree-of-freedom autonomous system of rotor motions is derived.•Bifurcation diagrams of self-sustained vibrations are analyzed.

A general approach for the vibration analysis of one disk rotor in arbitrary length journal bearings is suggested. The forces acting on the journals of the rotor are determined from the Reynolds equation. The power series with respect to the general coordinates and the general velocities of the journals are used to calculate the fluid film pressure. The coefficients of this power series are determined from the finite elements solution of the Reynolds equation. The obtained forces are used in the four degree-of-freedom dynamical system of rotor vibrations. The combination of the harmonic balance method and the continuation technique is used to obtain the self-sustained vibrations of the rotors. The self-sustained vibrations, which arise due to the Hopf bifurcation, are analyzed.