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Abstract

The behaviour of elastohydrodynamic contacts at high slide-roll ratios (SRR) differs markedly from that found in rolling conjunctions and at low SRRs. Behaviour is dominated by viscosity reduction due to shear-thinning and by temperature rises in the fluid and mating surfaces. These have a major influence on both the performance of smooth contacts and the behaviour of rough surfaces. This paper presents a set of experimental results for these conditions where artificial roughness in the form of transverse ridges is present. These are then compared to the results of a perturbation analysis to see whether this rapid analysis technique can adequately predict the behaviour.

It is shown that very powerful feedback mechanisms exist in both the thermal and shear thinning and that these make the behaviour of surface roughness relatively insensitive to changes in fluid properties.

In contrast to most previous work, real temperature, pressure and shear dependences of viscosity as measured in viscometers have been employed.

Keywords

Thermal EHL shear thinning surface roughness perturbation analysis

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A comparison of measured film thicknesses with quantitative predictions from an elastohydrodynamic,perturbation analysis at high slide-roll ratios

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