Predicting Natural Frequencies of a Hydrodynamically Lubricated Journal Bearing With Constant Oil Supply Pressure

Abstract

The analytical and experimental investigations reported here deal with the natural frequencies and system behavior of a full journal bearing subjected to a small sinusoidal load superimposed on a large unidirectional static load. The analysis, verified by experimentation, shows that the bearing can be regarded as two independent second-order systems acting perpendicular to each other. The variable coefficients of the equations of motion cause the bearing to behave as an underdamped system for low values of static eccentricity ratio ε0 , and as an overdamped system for intermediate values of ε0 . The bearing tends to be unstable above a particular ε0 . Further analysis is needed to determine the effects resulting from changing the oil inlet pressure.