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Gear coupling modification
Mahel, Pavel ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with the design of a gear coupling. The main intention is to design the optimal shape of the clutch gearing for the given operating conditions. Due to the special barrel shape of the teeth on the external gearing, these couplings enable the torque to be efficiently transmitted even in the case of misalignment of the connected shafts. In the case of an improperly designed coupling, a number of problems can occur that could affect the life of the coupling. These problems include in particular the generation of excessive vibrations and noise. It is necessary to choose the right lubrication system for long-term coupling life. To eliminate problems with gear couplings, it is necessary to ensure a suitable distribution of contact pressure at a given degree of misalignment. The introductory part of the thesis contains a comprehensive view of the issue of gear couplings. The next part deals with the structural design of the whole gear coupling and the improvement of the existing model. The following is a description and analysis of two different computational models of gearing that allow for different maximum degree of misalignment. The difference between the two gearing models is in the different geometry of the tooth shape on the hub. In the computational analysis, the most important monitored parameter was the course of contact pressure on individual teeth at a given degree of misalignment. From the performed computational analyses, result files are processed that compare the contact pressure and the number of teeth in engagement for different degrees of misalignment. The above analyses were performed using the finite element method in the calculation program Ansys Workbench.
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Biomechanical study of the upper limb wrist
Kouřil, Jan ; Marcián, Petr (referee) ; Florian, Zdeněk (advisor)
This master´s thesis is focused on biomechanical study of wrist. There is a literature search on this theme in the beginning of this work. The thesis is described in detail anatomy of bones in the wrist. Subsequent the stress-strain analysis of physiological wrist is implemented in a neutral position. The model of geometry of wrist is created on base of CT data. To create calculation model and the solution is implemented in the computer system ANSYS Workbench.
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Strain stress analysis of BS splint
Řehák, Kamil ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This master‘s thesis deals with strain-stress analysis of hip joint together with the final applied total endoprosthesis with Burch-Schneider cage. The main point of my work was to find the solution of stress–strain analysis state, which has been mentioned before in connection with Burch-Schneider cage. I describe the technique of geometric creation of whole body system, component´s materials or conditions which are neccessary for calculation. In coclusion there are results achieved in variants. In the first option the case of bone tissue was considered, which don’t reach degradation mechanical properties effect straining under Burch-Schneider cage. In some cases when the bone tissue is untimely forced, the necrosis of bone tissue takes place under Burch-Schneider cage. This possibility is described in the second option of type. For every option there was a case which was calculated with applied screw or without it. In all option mechanical features of cancellous bone tissue and their change influence on achieved results were considered. This problem was solved computational simulation in commercial software Ansys Workbench 12.0.
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Research study of mechanical properties of cranial tissue
Wojtek, Lukáš ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This bachelor thesis deals with the problematics of determining mechanical properties of cranial bone tissue. In this thesis a search study associated with an experimental determination of mechanical properties of bone tissues is executed. A brief history and progress of imaging methods and their importance of computation modelling are introduced. There are descriptions of histomorfometric parameters describing a structure of bone tissue at the micro level, ways of their computation and their impact on mechanical properties of bone tissue. Practical part of the thesis is focused on processing micro-CT images of cranial bone as well as analysing histomorfometric parameters (BV/TV, TbTh, TbSp) and subsequently stress strain analysis of selected sections of cranial bone tissue. Resulting Young´s modulus of elasticity of bone tissue [MPa] are compared with results from experiments from literature.
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Stress - strain analysis of save premolar tooth
Sáblíková, Zdeňka ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This diploma thesis deals with stress-strain analysis of healthy and save tooth. Defor-mation and stress of tooth system with a part of jawbone was solved by calculating method, FEM in computing system ANSYS Workbench 11. Stress-strain analysis of save of tooth was performed in twenty-five ways describing various classes and sizes of cavity, filling material and model of connection between the filling and the tooth.
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Stress - strain analysis of jaw with decrease bone tissue
Krpalek, David ; Fuis, Vladimír (referee) ; Florian, Zdeněk (advisor)
This diploma thesis deals with stress - strain analysis of jaw with decrease of bone tis-sue. At first was created a model of geometry using graphic program Rhinoceros 4.0 upon acquisition by the 3D scanner. That was converted to the computational system ANSYS Workbench 11 which uses for solving the finite element method (FEM). Solving was executed with homogenous, linear and isotropic material model of bone with different characteristics for compact and cancellous bone. Forces of the three working muscles, which participate on chewing, were given on the basis of the force and moment balance mandible. Solving was executed for 12 variant simulating occlusion in places, where was earlier found teeth.
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Stress-strain analysis of mandible with applied fixator due to the missing bone tissue
Fňukal, Jan ; Valášek, Jiří (referee) ; Marcián, Petr (advisor)
This thesis deals with the fixation of lower jaw with bone tissue defect using commercially produced fixator. Large defects of bone tissue are mainly caused due to the removal of bone tissue affected by tumor. These topics have been researched on the basis of the literature. Subsequently, stress strain analysis of the lower jaw with the applied fixation plate was performed. This analysis was solved by using computational modeling with variational approach, ie the finite element method. The work also describes in detail the procedure of creating model of geometry, model of material, model of boundary conditions and loads with subsequent solution of several computational models. The stress strain analysis was done for lower jaw with varying size of the removed bone tissue with applied reconstruction plate made of CP-Ti Grade 4 and for the lower jaw with the plate, which is made of -Ti-Mo. Finally, the influence of the mechanical properties of the callus during formation of new bone tissue (callus healing) on the stress and deformation of the solved system was evaluated.
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Stress-Strain Analysis of Shotgun Barells
Běhal, Josef ; Majer, Zdeněk (referee) ; Slažanský, Martin (advisor)
This bachelor’s thesis deals with stress-strain analysis of the shotgun barells. Gun was designed by company Česká zbrojovka a.s. Thesis contains an introduction to the functionality of weapons folowed by chapter dealing with shot from small shot shotgun. Stress-strain analysis was performed by finite element method. The final section shows the evaluation of achieved results.
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Computational modelling of stresses in intracranial aneurysms
Turčanová, Michaela ; Polzer, Stanislav (referee) ; Burša, Jiří (advisor)
The diploma thesis deals with the assessment of the prediction of brain aneurysm rupture based on its geometrical and material properties. In the first part of the thesis there is a~detailed research study of cardiovascular systems with a focus on the cerebral artery and aneurysm occurring on their bifurcates. The second part of the thesis is focused on the creation of two models of arterial cerebral bifurcation with the presence of aneurysm and on obtaining their geometry in unloaded state. Emphasis is placed on the most realistic constitutive model of the artery wall material based on real data from uniaxial tensile tests and on a suitably chosen blood pressure load. This blood pressure may be step-changed, for example, in bungee jumping. In the work, a calculation of the increase in blood pressure during the step-change is performed, which is subsequently used in calculations of tension in the wall of the cerebral aneurysm. In conclusion, the risk of rupture is evaluated in two model idealized brain aneurysms and a discussion of the credibility of the results is given.
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