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Machine component design has become a prominent topic for researchers in recent years. The analysis of bearing systems has received considerable attention in order to avoid detrimental contact. Among the most important studies in this area are the transient problems of journal bearings, which are usually performed by coupling the Reynolds equation with the motion equations. Many techniques have been presented in the literature and are still being explored to ensure the accurate findings and efficient solution prediction of unsteady state Reynolds equation. In this paper, the Proper Generalized Decomposition (PGD) approach is expanded for the analysis of the lubricant behavior of dynamically loaded journal bearing considering Swift-Stieber boundary conditions. The PGD model is applied in this problem, seeking the approximate solution in its separated form of the partial differential Reynolds equation at each time step during the load applied cycle employing the alternating direction strategy. Compared to the classical resolution, the PGD solution has a considerably low computational cost. To verify the accuracy and efficiency of this approach, three cases have been considered, infinitely short, infinitely long and finite journal bearings under the dynamic load. The results of the suggested methodology when compared to the full discretized model (FDM) show that, the new scheme is more efficient, converges quickly, and gives the accurate solutions with a very low CPU time consumption.

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A theoretical investigation of the static and dynamic behaviour of a rigid plain journal bearing lubricated by oils containing polymer additives considering misalignment defect is presented. The lubricating oils which are non-Newtonian are modelled as couple-stress fluids. According to the V. K. Stokes' micro-continuum theory which takes into account the size of particles, these fluids are characterized by two physical constants, namely the dynamic viscosity (μ) and a second characteristic responsible for the couple stress in the fluid (η). The effects of the couple-stress on the static and dynamic behaviour of the plain journal bearing are studied by defining of a dimensionless couple-stress parameter. The obtained results showed that the presence of additives in the lubricant has non- negligible effects on the static and dynamic performance characteristics as well as the dynamic stability and response of the journal bearing especially at high values of couple-stresses parameter, i.e. for higher chain length of the additive molecule. However, their influence on the side leakage flow is negligible except for high values of eccentricity ratio. [ABSTRACT FROM AUTHOR]

Abstract: The Elrod–Adams model is a pressure–saturation formulation which takes into account cavitation phenomena in thin fluid films mechanics. We study the asymptotic behavior of the model, using the two-scale convergence technique, in devices such as journal bearings. Interest is highly motivated by the roughness effects of the surfaces. Anisotropic effects appear on the coefficients, which is usual, but also on the saturation function, since various saturation functions appear through the homogenization process. To cite this article: G. Bayada et al., C. R. Acad. Sci. Paris, Ser. I 340 (2005). [Copyright &y& Elsevier]