Elastohydrodynamic lubrication analysis of polymer‐on‐polymer artificial hip joint of CF / PEEK composite

2015 ◽

Vol 736 ◽

pp. 140-145

Author(s):

Khanittha Wongseedakaew

Keyword(s):

Surface Roughness ◽

Film Thickness ◽

Hip Joint ◽

Initial Conditions ◽

Surface Condition ◽

Elastohydrodynamic Lubrication ◽

Human Movement ◽

Approximation Technique ◽

Artificial Hip Joint ◽

Artificial Hip

This paper describes the transient analysis of artificial hip joint during human movement under elastohydrodynamic lubrication (EHL) with non-Newtonian lubricants based on a Carreau model. During walking, the load and velocity are varying with time. The numerical schemes employed perturbation method, Newton-Raphson method and multi-grid multilevel with full approximation technique to solve the time-dependent modified Reynolds equation and elasticity equation with initial conditions. The aim of this study was investigated the characteristics of elastohydrodynamic lubrication, profile of film pressure and film thickness profile in human artificial hip joint during human movement. Numerical results show the transient film thicknessincreased and then decreased because of reverse motion. In smooth surface condition, film thickness for Newtonian fluids is slightly higher than the film thickness for non-Newtonian fluid. The amplitude of surface roughness has significant effect on the film thickness,the minimum film thickness decreased when the amplitude of surface roughness increases.

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Transient elastohydrodynamic lubrication analysis of ultra-high molecular weight polyethylene hip joint replacements

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406021525205 ◽

2001 ◽

Vol 216 (4) ◽

pp. 409-420 ◽

Cited By ~ 17

Author(s):

D Jalali-Vahid ◽

Z M Jin

Keyword(s):

Hip Joint ◽

Numerical Procedure ◽

Elastohydrodynamic Lubrication ◽

Squeeze Film ◽

Joint Replacements ◽

Artificial Hip Joint ◽

Artificial Hip ◽

Minimum Film Thickness ◽

Hip Joint Replacements ◽

Ultra High Molecular Weight

The cyclic variation in both the load and speed experienced during walking was considered in an elastohydrodynamic lubrication (EHL) analysis for artificial hip joint replacements in this study. A general numerical procedure was developed to take both the entraining and squeeze-film actions into the solution of the Reynolds equation in the spherical ball-in-socket coordinate, simultaneously with the elasticity equation, using the Newton-Raphson method. The numerical procedure developed was then applied to an example of hip joint replacements employing an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup against either a metallic or ceramic femoral head under simplified cyclic load and speed conditions. The predicted minimum film thickness was found to stay remarkably constant, despite a large change in the angular velocity and the load. This was attributed to the combined effect of entraining and squeeze-film actions in generating, replenishing and maintaining the lubricating film in artificial hip joint replacements. Furthermore, it was pointed out that the average transient minimum film thickness predicted throughout one cycle was very close to that under quasi-static conditions based upon the average angular velocity and load.

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