Couple stresses affect lubrication problems when additives are used or the lubricant contains long-chain molecules. Such couple stresses may have a significant effect on the behaviour of bearings in practice. The effect of couple stresses with and without rotational inertia on mechanical parameters of the curvilinear thrust bearing is considered. As an example we discuss simulation of the squeeze-film behaviour of a human joint modelled as a hemispherical nonspinning bearing. It is shown that the influence of couple stresses on the characteristics of the bearing discussed is significant and not negligible. The effects of couple stresses provide an enhancement in the pressure distribution and of the load-carrying capacity.

The present theoretical analysis is to investigate the effect of non-Newtonian lubricant modelled by a Rabinowitsch fluid on the performance of a curvilinear squeeze film bearing with one porous wall. The equations of motion of a Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation the modified Reynolds equation is obtained. The analytical solution of this equation for the case of a squeeze film bearing is presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. Thrust radial bearing and spherical bearing with a squeeze film are considered as numerical examples.

In the paper the influence of bearing surfaces roughness on the pressure distribution and load-carrying capacity of a thrust bearing is discussed. The equations of motion of an Ellis pseudo-plastic fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and using the Christensen theory of hydrodynamic rough lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for the cases of a squeeze film bearing and an externally pressurized bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. A thrust radial bearing is considered as a numerical example.

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Couple stresses affect lubrication when additives are used or the lubricant contains long‐chain molecules. Such couple stresses may have a considerable effect on the behaviour of bearings in practice. The influence of couple stresses and lubricant inertia on the mechanical parameters of a curvilinear thrust bearing with a squeeze film is considered in this paper. Simulation of the squeeze‐film behaviour of a human joint modelled as a spherical bearing is discussed as an example.