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Numerické simulace náhrad kolenního kloubu - dynamická kontaktní úloha se třením
Lanzendörfer, Martin
We shortly report on our endeavour after a numerical analysis of the biomechanical conditions in the human knee joint. We present here the mathematical model of a dynamical contact problem with friction in linear elasticity. A simple time discretisation by semi-implicit scheme is described and the algebraic saddle point problem resulting from the FEM discretisation is shown. The model should help us to simulate the function of natural human joint and/or the artificial prosthesis in the context of a dynamically loaded sceleton.
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Napjatostní analýza kyčelního kloubu s povrchovou náhradou - simulace chůze
Návrat, Tomáš ; Florian, Z. ; Fuis, Vladimír ; Štekl, M.
In the works dealing with computational hip join modelling, published on this subject in the past, the hip's loading is modelled so as to correspond to standing on one lower limb. At this standing, man remains symmetric at the considered level of resolution, and the force of gravity is identical with the body's axis. We consider the standing because man at walking always stands on one lower limb, and we suppose that, at this standing, in the hip joint there develops a maximum force (we do not suppose rapid walking or shock load). Since the computational models presented up to now consider the standing on one lower limb, it was decided to test computational modelling of even the step' next phase. The problem was formulated as follows: to make a strain-stress analysis of the hip joint with applied surface prosthesis for various phases of the step.
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Napjatostní a deformační analýza keramické hlavice totální kyčelní endoprotézy s tvarovými odchylkami kontaktních ploch
Fajfr, M. ; Fuis, Vladimír
The problem of the stress in the head of the hip joint endoprosthesis is solved by FEM. These shape variants of the contact areas were taken into account: accurate variant, deviation from the nominal conicalness, no roundness contact surfaces (modelling by the help of elliptically shaped), indirectness of contact surfaces, combination of no roundness and conicalness. The maximum of the first principal stress in the ceramic head decreases with the increasing of the angle of the loading. Deflections of the type no roundness create the highest values of maximum stresses in the head.
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