Napjatostní analýza keramické hlavice totální kycelní endorpotézy s mikro a makro tvaovými odchylkami

Stress Analysis of the Ceramics Head with Micro and Macro Shape Deviations of the Contact Areas

conference paper

en

The paper deals with the problems of ceramic head of hip joint endoprosthesis destructions in vivo, and with assessing the impact of shape deflections of conical surfaces on the tensile stress in the head. There are assumed two material characteristics of the stem – the first is linear elastic and the second is bilinear plastic modelled austenitic steel used in the bio-implants. Concerned are shape deviations from the ideal conical surfaces of the stem and the head of the endoprosthesis. The shape deviations may be modelled at the macro-level – this concerns model shape inaccuracies such as deviation from the nominal degree of taper, at the micro-level – when the stochastic distribution of unevenness on the contact areas is respected. The problem of stress in ceramic heads was solved using the algorithm of the finite element method – system ANSYS under ISO 7206-5 loading. In the paper are presented and analysed the results of solution of the macro-level shape deviations and micro-level shape deviations, obtained from measurements made on the cones of stems and heads.

Príspevek se zabývá vlivem materiálu dríku na napjatost v hlavici totální kycelní endoprotézy s mikro a makro tvarovými odchylkami.

The paper deals with the problems of ceramic head of hip joint endoprosthesis destructions in vivo, and with assessing the impact of shape deflections of conical surfaces on the tensile stress in the head. There are assumed two material characteristics of the stem – the first is linear elastic and the second is bilinear plastic modelled austenitic steel used in the bio-implants. Concerned are shape deviations from the ideal conical surfaces of the stem and the head of the endoprosthesis. The shape deviations may be modelled at the macro-level – this concerns model shape inaccuracies such as deviation from the nominal degree of taper, at the micro-level – when the stochastic distribution of unevenness on the contact areas is respected. The problem of stress in ceramic heads was solved using the algorithm of the finite element method – system ANSYS under ISO 7206-5 loading. In the paper are presented and analysed the results of solution of the macro-level shape deviations and micro-level shape deviations, obtained from measurements made on the cones of stems and heads.

Biomechanika, kyčelní endorpotéza, tvarové odchylky

Biomechanics, hip joint endorporsthesis, shape deviations

2008

29.09.2008

Praha

978-80-01-04163-5

Human biomechanics 2008

1–2

2