Steady-State Behaviour of the Rigid Jeffcott Rotor Comparing Various Analytical Approaches to the Solution of the Reynolds Equation for Plain Journal Bearing

A planar 2 DOF model of an unbalanced rigid disc on a massless rigid shaft (rigid Jeffcott rotor) is extended considering nonlinear forces in plain journal bearings. To express the fluid-film forces in the journal bearings, several approximate analytical solutions of theReynolds equation are used, including widely used approximations for infinitely long and infinitely short journal bearing and a method using correction polynomial functions to extend the area of aspect ratios. The differences in steady-state response of such a rotor are studied. The influence of the approximate solution type, eccentricity ratio and aspect ratio is analysed. The aim is to find out the more effective approach to journal bearing description which could be further used in detailed dynamical analyses of both stable and unstable dynamic behaviour along with nonlinear phenomena like bifurcations and transitions to chaotic motions.