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Biomechanical Study of Human Mandible in Physiological State
Borák, Libor ; Horyl, Petr (referee) ; Bartáková, Sonia (referee) ; Janíček, Přemysl (referee) ; Florian, Zdeněk (advisor)
This study deals with the mechanical aspects of human mandible in physiological state during the occlusion. The work is focused on evaluation of stress-strain conditions of bone tissue. The emphasis is paid to the interaction of teeth with the bone. In addition, contact pres-sures in temporomandibular joints during various loading conditions were determined. The analysis of material model of some parts of the system regarding their modelling-level is pre-sented as well. The problem concerning the evaluation of stress-strain states is solved by computational simulation using the finite element method. The presented work is a detailed analysis of the parts of the masticatory system and a thorough description of their modelling is presented. Special focus is paid to modelling of cancellous bone as well as of periodontal tissue which mediates the interaction between a tooth and the alveolar bone. Three-dimensional geometry of the mandible and all its teeth has been obtained by using the digitizing of real objects, namely by using of three-dimensional optical scanner. Three various modelling levels of the material of periodontium are assessed: Linear iso-tropic model, bilinear isotropic model and linear orthotropic model. Characteristics of these models are analyzed and especially nine new constants describing orthotropic model (which is almost absent in the literature) are proposed. Two-dimensional models are used for analysis of differencies in mechanical response of cancellous bone to the tooth loading. Two cases are considered: Cancellous bone as a ho-mogenous continuous model on one hand and with detailed trabeculous architecture model on the other. Computational model is divided into four basic cases varying in level of masticatory appa-ratus geometry: A – 2D geometry of bone; B – 3D geometry of bone segment with one tooth through three teeth; C – 3D geometry of whole mandible with the only tooth; D – 3D geome-try of whole mandible with all teeth. All basic cases are further researched in different varia-tions for different material models etc.
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Proposal of a new type of steam turbine blade attachement
Vrbický, Jiří ; Petruška, Jindřich (referee) ; Polzer, Stanislav (advisor)
This thesis describes design of new circumferential blade attachment on last grade of steam turbine and following stress-strain analysis by FEM with static and cyclic loading. It was created two new design of geometry, which were created based on existing and operating constructional solution of oblique double T blade attachment. It was made stress-strain FEM analysis on original design of blades. Its results served to realize change of construction. Their target was increase load capacity and service life of new types of blade attachment.
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Stress-strain analysis of the LKDS800 frame
Tománek, Jiří ; Vlk, Miloš (referee) ; Vosynek, Petr (advisor)
This diploma thesis deals with frame of the two-point crank press LKDS800, which was designed by company ŽĎAS a.s. Frame is welded construction creating the base of the press which has mass approximately 90 tonnes. Aim of this study was to perform strain-stress analysis of the frame. From obtained results perform optimization of mass this frame leading to reduce material costs and machining. In the process is frame loaded by nominal forces from the shearing process, under its own weight and inertia forces caused by moving components. As a result of the dynamic loading in welded joints there are risks of fatigue fracture. The manufacturer of the press is required to find the most loaded welded joint and it to assess the fatigue life.
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Stress-strain analysis of aortic aneurysms
Man, Vojtěch ; Janíček, Přemysl (referee) ; Burša, Jiří (advisor)
This master thesis is focused on stress-strain analysis abdominal aortic aneurysm using ANSYS software. The model of abdominal aortic aneurysm are based on CT scans of five specific patients. The branching arteries are included to the model and one goal of this thesis is decision about their influence of the wall stress. In this thesis was used a hyperelastic materiál model, which is based on mechanical tests done on human arterial samples.
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Stress-strain analysis of arterial aneurysms
Tesařová, Petra ; Skácel, Pavel (referee) ; Burša, Jiří (advisor)
The diploma thesis is focused on the creation of the aneurysm finite element model and the making of the aneurysm wall stess-strain analysis using ANSYS software. The model of abdominal aortic aneurysm geometry starts from the CT scan of the particular patient. In the thesis there are compared two chosen constitutive models, each of them appears from different mechanical tests done on human arterial fibre samples. Furthermore, a limiting condition for aneurysm wall structure damage is expressed. On the basis of the results of stress calculation in the aneurysm wall and the limiting condition, the safety coefficient and rupture factors risk are worked out.
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Stress - strain analysis and creep assessment of the thick-walled tubular structures.
Zouhar, Michal ; Petruška, Jindřich (referee) ; Hlavoň, Pavel (advisor)
This thesis deals with the stress-strain analysis of thick-walled pipe parts. The dimension series (characterized by the D/d ratio) of three components are solved, then a direct tube, a torus with constant wall thickness (arcus) and a torus with variable wall thickness (bend). At first, the internal pressure amount, when a fully plastic state for these components is created, is solved. The amount of the limit pressure is determined analytically, numerically and by appropriate normative relations. The results and stress diagrams of individual solutions are mutually compared. Furthermore, these components are solved in the creep and are exposed to the maximum allowable normative internal pressure for 200,000 hours according to the standard – the operating time of components. The place of the maximum equivalent creep strain and the place of the maximum equivalent stress is examined. In these places the principal stresses are depicted depending on the D/d ratio. The results and stress diagrams of individual dimension series are mutually compared. From the available literary sources the condition of the limit state reach is chosen, according to which the evaluation of the limit state reach for individual components is carried out.
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Shape optimization of shield of asynchronous machine
Dítě, Pavel ; Hadaš, Zdeněk (referee) ; Dušek, Daniel (advisor)
The subject of this diploma thesis is to optimize the shield of asynchronous motor. In the thesis are given results of modal and the strain-stress analysis made for model of the shield, which is currently produced. To resolve this issue was used CAE programming system Pro/MECHANICA, which is based on method of geometric elements – GEM. The main output of this work is proposal of two new optimized shields of asynchronous motor and for these are presented results of modal analyse and the strain-stress analysis. Part of the thesis is design and technical-economic evaluation of casting methods for new shield production.
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Stress-strain analysis of artery with atheroma
Maša, Marek ; Návrat, Tomáš (referee) ; Burša, Jiří (advisor)
The main goal of this diploma thesis was the stress-strain analysis of iliac artery with atheroma.This problem was solved using finite element method (FEM).For the calculation purposes three two-dimensional models were created. The geometry was gained from transversal sections through the iliac artery with ateroma. This geometry is educed from used literature review. The main calculation process was run by ANSYS 11.0 program system.
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Stress strain analysis of dental implant
Snášelová, Dana ; Florian, Zdeněk (referee) ; Marcián, Petr (advisor)
This bachelor thesis deals with stress strain conditions at interface of dental implant and bone of mandible in two-dimensional space. To solve these proportions the finite element method was used. Solution was realized in finite element software Ansys Workbench 15. This thesis also offers comparsion between different samples, which vary in bone density and type of dental implant.
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