0
RESEARCH PAPERS

Elastohydrodynamic Lubrication Modeling of Artificial Hip Joints Under Steady-State Conditions

[+] Author and Article Information
F. C. Wang

School of Mechanical Engineering,  University of Leeds, Leeds LS2 9JT, UK

Z. M. Jin1

School of Mechanical Engineering,  University of Leeds, Leeds LS2 9JT, UKz.jin@leeds.ac.uk

1

Corresponding author.

J. Tribol 127(4), 729-739 (Mar 22, 2005) (11 pages) doi:10.1115/1.1924460 History: Received March 17, 2004; Revised March 22, 2005

A general steady-state elastohydrodynamic lubrication model was developed for artificial hip joints, with particular reference to the effect of the anatomical position of the cup and the three-dimensional physiological loading and motion experienced during walking. Appropriate spherical coordinates and mesh grids were employed to facilitate the numerical solution. A specific hip implant employing an ultrahigh molecular-weight polyethylene acetabular cup against a metallic femoral head was chosen to demonstrate the general applicability of the lubrication model and the effects of both the cup inclination angle and the combined flexion-extension and internal-external rotation on the lubrication were analyzed.

FIGURES IN THIS ARTICLE
<>
Copyright © 2005 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 5

Comparison of the predicted film contours and/or profiles (a) and pressure distributions (b) between different cup inclination angles using the simplified anatomical lubrication model shown in Fig. 1 and the mesh grid shown in Fig. 2 under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis and a fixed vertical load of 350N. (c) Comparison of the predicted minimum film thickness for different cup inclination angles using the simplified anatomical lubrication model shown in Fig. 1 and the mesh grid shown in Fig. 2 under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis and a fixed vertical load of 350N.

Grahic Jump Location
Figure 6

Comparison of the predicted minimum film thickness between two different cup inclination angles of 0 and 45deg using the simplified anatomical lubrication model shown in Fig. 1 and the mesh grid shown in Fig. 2 under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis and different vertical loads

Grahic Jump Location
Figure 7

Effect of the internal-external rotation around the vertical axis on the predicted film contours and/or profiles (a) and pressure distributions (b) using the lubrication model shown in Fig. 1 for a cup inclined at 45deg and the mesh grid in Fig. 2 under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis and a fixed vertical load of 2500N.

Grahic Jump Location
Figure 1

Ball-in-socket lubrication models for artificial hip joints: (a) full anatomical model with the three-dimensional load and velocity components, (b) simplified anatomical model with the vertical load and the flexion/extension, (c) simplified anatomical model with the load and motion resolved into the cup coordinates, and (d) simple model for a horizontally positioned cup with the vertical load and the flexion/extension.

Grahic Jump Location
Figure 2

(a,b) Two spherical coordinates and correspondiong mesh grids, with z-axis being always aligned with the pole of the spherical coordinates

Grahic Jump Location
Figure 3

Comparison of the predicted film contours and/or profiles (a) and pressure distributions (b) for the simple ball-in-socket model shown in Fig. 1 (horizontally positioned cup) under a fixed-horizontal angular velocity of 2rad∕s around the medial-lateral axis and a fixed vertical load of 2500N between two different spherical coordinates and mesh grids shown in Fig. 2(ωz=2rad∕s) and Fig. 2(ωx=−2rad∕s). Comparison of the predicted minimum (c) and central (d) film thicknesses for the simple ball-in-socket model shown in Fig. 1 (horizontally positioned cup) under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis and different vertical loads between two different spherical coordinates and mesh grids shown in Fig. 2(ωz=2rad∕s) and Fig. 2(ωx=−2rad∕s).

Grahic Jump Location
Figure 4

Comparison of the predicted film contours/profiles (a) and pressure distributions (b) between the two different lubrication models shown in Figs.  11 using the mesh grid shown in Fig. 2 under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis, a fixed cup inclination angle of 45deg, and a fixed vertical load of 2500N. Comparison of the predicted minimum film thickness between the two different lubrication models shown in Figs.  11 using the mesh grid shown in Fig. 2 under a fixed horizontal angular velocity of 2rad∕s around the medial-lateral axis, a fixed cup inclination angle of 45deg, and different vertical loads.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In