Engineering Mechanics

Proceedings Vol. 11 (2005)

ENGINEERING MECHANICS 2005

Copyright © 2005 Institute of Mechanics of Solids, Faculty of Mechanical Engineering, Bruno University of Technology, Brno

 

Koukal M., Florian Z.
pages 165 - +8p., full text

This paper belongs to biomechanics of a hip joint section. It is engaged in problems with industrial tolerances for dimensions as one of the possible total hip prosthesis insufficiency. There can be a lot of reasons for failing of hip prosthesis (for example unfit materials, unfit construction, etc.). And there are also a lot of types of failure (for example break of prosthesis, pull-off of the components etc.). It was found that there is not uniform abrasion on removed parts from human body during the analysis on components of total hip prosthesis. On unused parts it was found that there are not the same tolerances for dimensions at the same components from different producers. During the pushing of the ball head into acetabulum we can find out that some pairs show out a clearance, some show the interference and in some cases we can say that they have a fine fit. 2D and 3D computation models of a ball head, acetabular fossa and pelvis were made, on which interference or clearance fits and real loading conditions during the slow walk of a human were simulated. Ascertained were values of contact pressure and frictional moment needed to turn ball head in acetabular fossa. Finite element method (FEM) system ANSYS was used for computations.

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