Measured Characteristics of a Journal Bearing Oil Film

This paper presents the results obtained from two experimental methods of measuring the nonlinear characteristics of the eight coefficients which specify the lateral flexibility of a hydrodynamic journal bearing. Measured coefficients are given for both positive and negative discursion of the relevant journal center velocity or displacement from the static equilibrium position which occupied a range of eccentricity ratios. Coefficients are expressed in terms of a “zero” value and linear gradient. No difference was established between displacement coefficients deduced from the two experimental techniques. All zero velocity coefficients were found to be invariant with eccentricity ratio within 0.779 to 0.87, but to vary inversely with vibration/rotation frequency ratio. Eccentricity ratio was found to affect only zero displacement coefficients associated with vertical discussion, when greater than 0.87. Displacement coefficient gradients are shown to be only influenced by eccentricity ratio when the same is greater than 0.78. When possible, comparisons are made with other published results.