Experimental determination of the steady-state and dynamic characteristics of fluid film bearings with results for a two-axial groove journal bearing

A hydrodynamic bearing test rig was successfully developed to study the steady operating characteristics and dynamic coefficients of fluid film bearings. Results are presented from an experimental and theoretical investigation of a 2-axial groove journal bearing.; Using two electrodynamic shakers to generate synchronous, sinusoidal excitations, two independent and small elliptical displacement orbits were produced for different static equilibrium positions. The four linearized stiffness and four linearized damping coefficients were determined by an average magnitude and phase method. The coefficients are presented in dimensionless form as functions of the Sommerfeld number. Data was taken for two fixed shaft speeds while the steady load was varied to achieve eccentricity ratios ranging from 0.519 to 0.855 and Sommerfeld numbers from 0.063 to 0.344. Typical average uncertainty was of the order of 12% for the coefficients and 8% for Sommerfeld number.; For the speed, load, and temperature ranges tested herein, coefficient results from each speed line overlaid well, supporting the first order approximation that, at least for these three variables, a coefficient's magnitude is independent of the manner in which Sommerfeld number is arrived. Experimental evidence was found to support the theoretical finding that the cross-coupled damping terms are of equal magnitude. Additional experimental results include eccentricity, continuous oil film thickness and pressure profiles and discrete temperatures.