This paper presents idea flow, development and construction of an anthropomorphic hand which is intended to be used mainly in prosthetics. Fundamental results of simulations and optimization of grasp are shown. The prototype has been manufactured and the principal functionality of finger mechanism (drive three axes by one string) has been tested. A new mechanical principle has been developed which is based again on an idea of using less actuators then joints with keeping adaptability and functionality of the mechanism. and Obsahuje seznam literatury
In endoprosthesis surgery there are typically a high percentage of implant defects, these can lead to failure of the whole prosthesis. One type of total hip replacement function loss is acetabular cup loosening from the pelvic bone. This article examines manufacture perturbations as one of the possible reasons for this kind of failure. Both dimension and geometry manufacturing perturbations of ceramic head and polyethylen cup were analyzed. We find that perturbations in the variables analysed here affect considered values of contact pressure and frictional moment. Furthermore, contact pressure and frictonal moment are quantities affecting replacement success and durability. From obtained results we can recommend to fit head and cup with a clearance of between 0 mm andd 0.05 mm. We do not recommend using interference type of fit. Roundness perturbation of ceramic head should not exceed 0.025 mm. and Obsahuje seznam literatury
The previously developed thoracic finite element model [8, 9] was used to investigate the human thoracic dynamic responses associated with the frontal, lateral and oblique loading and to predict injuries of the thorax associated with the frontal loading. The thoracic model was developed [8, 9] to improve the human articulated rigid body model ROBBY (the model of an average adult male) [13, 14], which was previously developed at the University of West Bohemia in cooperation with ESI Group (Engineering Simulation for Industry). There are implemented deformable models of the thorax and abdomen in the ROBBY model. The geometries of individual thoracic organs were based on the cadaver tomography data and color cross-section photographs obtained from Visible Human Project (VHP) [33]. The thoracic model material properties were obtained either by virtue of cooperation with ESI Group or from public sources (articles, Internet, books). Thoracic model includes the models of the sternum, ribs, costal cartilages, vertebrae, lungs, heart, trachea, main vessels (aorta, vena cava superior), intercostal muscles, diaphragm, flesh and skin. The presented study deals with the dynamic response and validation of the whole thoracic model and with the prediction of thoracic injuries by virtue of this model. The results of simulations are compared with the experimental results. and Obsahuje seznam literatury
This article studies several aspects of problems associated with diseases of big joints. It is an introductory essay to another three articles that focus on solving various biomechanical problems in hip joint. Stress limit states on contact surfaces of the hip joint can be considered as a common denominator of all these problems. General analyses of these states are described in a separate part of this article. Other general analyses concern the complex of problems associated with diseases of big joints. As an illustration (in view of the articles that follow), this article includes a systemic conception on analysis of the applicability of biomechanics in solving therapeutic problems of big joints. As an illustrative example, the hip joint was selected. and Obsahuje seznam literatury
The aim of our work is to confirm mathematic model of pressure distribution in knee replacement. The mathematic model has been made by A. Donat from CTU. This model deals with pressure distribution in femoral and tibial components which was counted by application ABAQUS. The mathematic model counted areas with maximal pressures. We will verify only these areas. and Obsahuje seznam literatury
This work presents the procedure of a computational model of pathological hip joint allowing a simple modification of individual parts of the model according to the planned course of femoral and pelvic osteotomy. Both presented models were subjected to strain-stress analysis by a finite element method using the ANSYS program system. The obtained results are compared with physiological hip joint results and the feasibility of planned osteotomy is evaluated based on selected mechanical parameters. The conclusions are consulted with surgeons and possible corelations with clinical results are searched for. and Obsahuje seznam literatury
The article presents the mathematical model non-homogenous, isotropic environment, where is possible to create various types of flows (the chemical reaction flow, the diffusion flow, the heat flow, the electromagnetic flow). and Obsahuje seznam literatury
Possibility of substituting the affected hip joint with endoprothesis is - for many people all over the world - the only way for returning to the normal life without pains and significant motion limitations. But the age limit requiring the application of replacement becomes lower and lower. The endoprothesis applied to young patients must be replaced several times during their lives and the application and repeated replacements affect the bone so that it may happen that the next application may not be possible any more. For such cases the surface replacement the propose of which is to postpone the need of the first application of the classic total endoprothesis, has been invented. So that the objective of the contribution consists in creating a computing model of the healthy hip joint and the hip joint with the classic total hip replacement and with the surface replacement, in carrying out the stress-strain analyses, and in mutually confronting the results obtained. The problem has been solved as a direct task by means of computational modelling, by the method of finite elements in the ANSYS. The computational model consists of these components: sacral, pelvic and femoral bone, muscles, cup, and femoral compponent. and Obsahuje seznam literatury