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Biomechanical studies of knee jointarthroplasty
Zděblo, Jakub ; Valášek, Jiří (referee) ; Florian, Zdeněk (advisor)
The presented diploma thesis deals with stress-strain analysis of the intact human knee joint and the knee joint after reconstruction using fixation plate. Finite element method is used to determine the biomechanical response of the knee under loading with the FE software Ansys. The three-dimensional finite element model is consisted of bony structures (femur and tibia) which were created using computed tomography (CT) data, articular cartilages and both menisci. Model of the locking plate (LCP) was created based on producer's technical guide. Three models of the knee joint with LCP fixation plate are created for three different sizes of condylar fragment based on the intact model. On all variants is applied loading corresponding to maximum loading in a gait cycle. The results show that reconstruction of the knee joint with locking plate has no effect on changing in contact pressure on tibial plateau.
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Biomechanical study of the proximal part of the femoral intermedullary nail
Hrdlička, Jan ; Valášek, Jiří (referee) ; Florian, Zdeněk (advisor)
The presented Master Thesis is focused on the structural analysis of the proximal femur on which the Proximal Femoral Nail (PFN) and Proximal Femoral Tele-Screw (PFT) systems are applied. These systems are used for a treatment of the intertrochanteric and femoral neck fractures. However, in some cases a loss of stability of the systems may be expected. The presented thesis describes a development of numerical models in which stress distribution of implants and strain distribution of bone tissue are compared. Numerical models were created from real objects. The model of femur geometry was created by using the Computed Tomography (CT). Boundary conditions of the model were estimated from the force equilibrium of the lower limb. All numerical models were processed in the commercial package ANSYS Workbench v15.0. It is shown that the hip screws of the PFN system result in lower equivalent stresses than the screws of the PFT system. Maximal strains of the bone tissue, when using the PFN system, are situated near the fracture, close the hip screw thread. For the PFT system, the maximal strains are only near the area of fracture.
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Strain stress analysis of hip joint with thinking of wear after total hip endoprothesis
Ebringerová, Veronika ; Valášek, Jiří (referee) ; Florian, Zdeněk (advisor)
The presented work deals with the creation of computational model of total hip endoprosthesis and the subsequent stress-strain analysis. The models of geometry of the pelvis and femur were created on base of CT data. In this model were fitted components od endoprosthesis, i.e. femoral stem and acetabular cup (metal and polyethylene pad) and also cement. On this system was subsequently modelled the rals loads conditions. Just the real loading of the prosthesis leads to the wear. It has a great influence on the quality of bone tissue, what is deteriorated. The deteriorated tissue was simulated under the acetabular component. The behaviour of the whole system is assessed on base of stress-strain analysis. This problems is very topical these days.
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Strain stress analysis of proximal femur with dynamic hip plate
Kohoutek, Jan ; Valášek, Jiří (referee) ; Florian, Zdeněk (advisor)
The presented Master’s Thesis aims at determining stress and strain distribution in proximal femur with applied PCCP and DHS systems. The DHS system has been widely and successfully used for treating intertrochanteric fractures of proximal femur; in some cases, however, complications concerning implant cut-out and excessive fracture collapse occur. To minimize the risk of stabilization failure, the PCCP system was designed. In the Thesis, the process of creating the numerical model is described and the results obtained by employing Finite Element Method are presented. The 3D models of implants’ geometry were created based on the real objects. The model of proximal femur geometry was built by utilizing a series of CT scans and divided into two bodies with respect to the AO classification afterwards. The loading was obtained by solving the static equilibrium equations for the loose lower extremity. The computation was run in Ansys Workbench v13 software. In the hip screws of the PCCP system, lower values of equivalent stress can be found when compared to the DHS system. However, the equivalent strain generated in the proximal fragment is 3-times higher when the PCCP system is employed than in case of DHS system which may be due to the self-cutting design of PCCP screws. By employing PCCP system, the risk of implant failure is decreased. On the other hand, the bone tissue of the proximal fragment in close vicinity of the implant screws seems to be overloaded and prone to collapse.
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Strain-Stress analysis of pig femur
Legerský, Radek ; Valášek, Jiří (referee) ; Florian, Zdeněk (advisor)
This master’s thesis deals with the strain-stress analyses of the pig femoral bone in physiological and pathological condition. Pathological condition is determined by a significant defect in diaphysis of the bone fixed by using direct angular stable locking plate with screws. The thesis describes the creation of computational models with special focus on bone tissues models of material, which are based on analysis of digital images from computed tomography (CT). There are created and analyzed three types of computational models: the first one corresponds to physiological condition of femur, the second one to femur with significant defect and fixation plate and the third one to femur with significant defect, fixation plate and rod. Every model is loaded in three ways: the first of them simulating the experimental conditions of pressure testing of the femur, the second one bone stress in the sagittal plane and the third one stress by using load determined from probational release of the pig hind limb. Strain-stress states are determined by finite element method using Ansys computational system. Gained results of stress and strain are compared with experimental measurements. The thesis presents a basic idea of the mechanical behavior of porcine femur and porcine femur with significant bone defect.
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Stress - strain analysis of save first molar tooth
Valášek, Jiří ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This diploma thesis specialises in stress – strain analysis of the save tooth. Concretely this thesis works with the save tooth with cavity of the I. and II. class. At the beginning of this work you can find description of basic filling materials, different ways of cavity´s preparation and subclassification of cavity. This work describes production of geometric model of health and save tooth with cavity of the I. and II. class. Model geometer of the save tooth was im-plemented in several ways, each one concerning different form of cavity, size of cavity and different filling materials. Final element net was created on the base of these geometric mo-dels. Computational model was created with the help of the programme ANSYS 11.0 in gra-phic environment Workbench and with the help of the final elements method. The results of the analysis are following: Continuity of the save tooth happens to break thereby the whole stiffness decreases in comparison with the save tooth. Two filling materials were used for sanitation of the tooth: amalgam and composite resin. As a result of the analysis I consider amalgam to be more suitable for sanitation of teeth in moral section.
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Resource Planning For Project Management
Ježek, Filip ; Valášek, Jiří (referee) ; Smolíková, Lenka (advisor)
The diploma thesis focuses on initial planning of human resources at quotation phase at enviroment of APV company, for purposes of project management. It analyse initial planning of projects and compare it with actual state at the end of project. It contains suggestion, which may lead to more accurate initial planning.
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Methods of measurement of bone density
Konvalinka, Jan ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This bachelor's thesis focuses on methods for measuring bone density and consequences of changes in bone density on biomechanical properties of bone tissue. In first part are described methods of bone densitometry, especially radiological methods, which are currently most widely used. Second part focuses on measuring bone density from CT images (hog femur bone, healthy and damaged human femur bone and lumbar vertebra) using software ROI Analysis. Third part discusses influence of changes in bone density on strain-stress quantities of trabecular bone. For the assessment was created 2D computational model of hip using FEM.
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The role of imaging techniques in creation of computational models in biomechanics.
Prášilová, Eva ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
The first part of the bachelor´s thesis is dealt with the processing history of imaging techniques and their indications in a clinical practice. From point of view of the computer modeling, the computer tomography plays an important role in biomechanics. The second part of this treatment describes the scan processing of sections of two human mandible obtained from computer CT and micro-CT tomography. As a non-invasive way procedure can be characterized the image processing techniques, which analyze a bone density and BVF. The manual segmentation was applied in this analysis provided in ROI analysis software. There are shown the graphs of the bone densities of segments of two human mandibles depending on the specimen length and also there are compared the results of the measurements received from the CT and micro-CT tomography. Then follow the results illustrating the correlation of the relations and recalculations, which can be used as the determination tool of the mechanical properties of bone tissue. Finally there are described the computer models created in ANSYS focused on the different bone density analysis and stress strain analysis.
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Dokumentace pro realizaci dřevostavby rodinného domu
Valášek, Jiří
In those diploma work work tie together on the work of bachelor degree, in which I'm proposed one-family house frame wood - construction. Thesis treat of production documentation one-family house. Work includes part graphical, that contains project part and production. Here are plotted all peripheral and inner wall and circumscribed all appropriate machinery appurtenances, that concern production documentation. In text parts come out constructive system and his outlines for realization construction. Be here composition construction siding, that are further thermally- technically advised in software -- warm. Work is supplemented about accompanying and technical report.
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