Elastohydrodynamic Lubrication Analysis of a Compliant Journal Bearing Considering Static and Dynamic Deformations of the Surface Coating

In this paper, the effect of both static and dynamic deformations of the bearing-liner on the dynamic performance characteristics, stability and unbalance response of a water-lubricated rubber-lined journal bearing operating under small harmonic vibrations is theoretically investigated. To take into account the dynamic deformations of the bearing-liner, the first order perturbation technique is used to determine the eight dynamic coefficients for a given excitation frequency value. The static and dynamic deformation of the fluid/bearing-liner interface is assumed to be proportional to the steady-state and dynamic fluid-film pressures. It was found that the dynamic properties, stability and unbalance response of the compliant journal bearing are affected by surface coatings from soft materials. It was also shown that when dynamic deformations are considered in the calculations, the dynamic coefficients depend on the excitation frequency, especially for higher values of this parameter. Moreover, the two cross damping coefficients differ from each other, while the classical elastohydrodynamic (EHD) theory predicts them equal, i. e., when the dynamic deformations are ignored.