A simple theory of asperity contact in elastohydro-dynamic lubrication

There is currently much discussion over the use of ceramic femoral components against metal acetabular cups, for use in total hip arthroplasty. The current study investigates six hot isostatically pressed alumina femoral heads of 38 mm diameter articulating against six as-cast Co—Cr—Mo metallic acetabular cups. Standard walking-cycle simulator wear testing was carried out to 5×106 cycles using the Durham Mark II hip wear simulator, and wear was determined gravimetrically. In addition, surface topography, using a non-contacting profilometer, an atomic force microscope, and an optical microscope, was monitored throughout the wear test. The wear of the ceramic heads was found to be undetectable using the current gravimetric method; however, a change in the surface topography was seen, as grain removal on the pole was observed through atomic force microscopy analysis. A biphasic wear pattern was found for the metallic cups, with low wear rates of 1.04 ± 0.293 mm3/106 cycles (mean, ±95 per cent confidence interval) and 0.0209 ± 0.004 mm3/106 cycles (mean, ±95 per cent confidence interval) for running-in and steady state wear phases respectively. Frictional measurement revealed that the joints were tending towards full fluid-film lubrication in parts of the walking cycle. The results show that the combination of hot isostatically pressed alumina and as-cast Co—Cr—Mo is a promising alternative for total hip arthroplasties.

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“…3, full fluid-film lubrication is predicted [36]. If l , 1, then the bearing would theoretically operate in boundary lubrication.…”

Section: Friction: Theoretical and Practicalmentioning

confidence: 99%

Tribological and surface analysis of 38mm alumina–as-cast Co–Cr–Mo total hip arthroplasties

Williams

Unsworth

et al. 2009

Proc Inst Mech Eng H

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“…where 1 E and 2 E are the elastic modulus of the slider and the plane, respectively; 1  and 2  are the Poisson's [27].…”

Section: Asperity Contact Modelmentioning

confidence: 99%

Analysis of the coated and textured ring/liner conjunction based on a thermal mixed lubrication model

Meng

Zhang

2017

Friction

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For the ring/liner conjunction, well-designed surface texturing has been regarded as a potential means to improve its tribological performance, as well as the application of coating. However, so far most researchers focused on the one of these aspects. In this study, the combined effect of coating and texturing on the performance of ring/liner conjunction is numerically investigated. A thermal mixed lubrication model is presented. The effects of the coating's thermal and mechanical properties on the tribological performance are studied under the cold and warm engine operating conditions. Along with the increasing coating thickness, the effects of the coating's thermal properties on friction loss are found to be significant, as well as the effects of the coating's mechanical properties. It is also found that a soft coating with a lower thermal inertia has a greater ability to reduce the friction loss of the textured conjunction.

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“…We proceed as in section 3, substituting (49) in (30) and making use of (50). After some manipulation it appears that in terms of the dimensionless forms given in (39)…”

Section: The Effect Of Micro-slipmentioning

confidence: 99%

The mechanics of the contact between deformable bodies

1975

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A simple theory of asperity contact in elastohydro-dynamic lubrication

Cited by 403 publications

References 6 publications

Tribological and surface analysis of 38mm alumina–as-cast Co–Cr–Mo total hip arthroplasties

Tribological and surface analysis of 38mm alumina–as-cast Co–Cr–Mo total hip arthroplasties

Analysis of the coated and textured ring/liner conjunction based on a thermal mixed lubrication model

The mechanics of the contact between deformable bodies

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