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Stress-strain analysis of Kozlov lookout tower
Winter, Josef ; Vaverka, Jiří (referee) ; Fuis, Vladimír (advisor)
Bachelor thesis is aimed at stress and deformation analysis of strut frame. The object of interest is lookout tower Kozlov close to the city of Česká Třebová in region of Ústí nad Orlicí in Pardubice Department. The main aim is to simplify 3D model of strut frame and its analysis. At the beginning I deal with history of lookout towers, theoretical introduction of bar, strut frames and limit states. Then follows modelling of 3D model with modified topology of bars and following calculation for different static loading and calculation for static determination. At the end numerical calculation was done to compare chosen model with analytic solution.
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Solution of the exact differential equation of deflection curve
Šikl, František ; Fuis, Vladimír (referee) ; Vaverka, Jiří (advisor)
This bachelor thesis deals with the deformation of a beam loaded with a basic bend using the differential equation of the deflection curve. The work is divided into four parts, where in the first part the general form of the differential equation of the deflection curve, which is based on simple geometry and mathematical approximations, is derived. In the second part, we will describe the basic methods of solving the differential equation of the deflection curve for large deformations for simple cases, where we must use the nonlinear form of the already mentioned equation. However, we will also mention methods that can be used for specific cases. In the third part, two numerical methods, which can be used to solve large deformations of beams, are being programmed. The last part describes the difference between the linear equation of the deflection curve, which is simplified and taught commonly, and the nonlinear differential equation of the second order. The fundamental task of the work is a comparison of commonly used methods to determine the deformation of the beam and to determine the degree of load, when it is possible to use a simplified differential equation of the deflection curve, and when not. However, it is important to mention that the numerical solution cannot always be used, so the example will be embedded in a simple case.
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Design of cylindrical apparatus for determination of directions of reinforcing fibres in aorta in its deformed state
Král, Martin ; Vaverka, Jiří (referee) ; Burša, Jiří (advisor)
This bachelor thesis deals with the design of cylindrical apparatus, which allows the cont- rolled biaxial deformation of a cylindrical sample of the aorta. This apparatus is designed to determine the direction of collagen fibers in the deformed aorta. The theoretical part of the thesis is focused mainly on description of the structure and mechanical properties of the wall of the aorta. In the design part, attention is paid to the design of the cylindrical apparatus. In the conclusion, the deformation of the cylindrical sample of the abdominal aorta from the pig is carried out on the apparatus and its strain is measured.
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Design of apparatus for determination of directions of reinforcing fibres in soft biological tissues in their deformed state
Sodomka, Tomáš ; Vaverka, Jiří (referee) ; Burša, Jiří (advisor)
The Bachelor´s thesis is focused on the determination of directions of collagen fibres in elastic arteries. The first aim of this thesis is a general introduction into soft tissue mechanics with turning attention to connective tissue where collagen fibres are their inseparable part. Also the thesis introduces arrangement of collagen fibres, their waviness and how the waviness thwarts determination of direction of fibres. The second aim is a design and test of the mechanical apparatus, which is able to stretch a squared aortic sample in two perpendicular directions (independently on each other) up to the relative deformation of 30 %. Design of the apparatus allows the sample to be dipped into the formaldehyde solution, which fixes the deformation. Consequent histologic sections of the sample will be used for the determination of global directions of collagen fibres in the aorta. The apparatus is designed to simulate conditions in a human or animal body where aorta is axially pre-stretched and at the same time expanded in the radial direction by blood pressure.
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Computational modelling of heart contraction
Vaverka, Jiří ; Polzer, Stanislav (referee) ; Burša, Jiří (advisor)
This thesis aims to determine the impact of slowed myocardial conduction velocity and depressed myocyte contractility on the duration of isovolumic contraction time (ICT) of the left ventricle by carrying out simulations using finite element method. A 3D finite element model enabling to simulate both physiological and pathological states of myocardium was created. The model is based on simplified ellipsoidal geometry and accounts for anisotropic behavior of myocardium, its asynchronous contraction and variations in the arrangement of muscle fibers. Slowing of conduction velocity to a half of its physiological value resulted in prolongation of ICT by 27 %; slowing of shortening velocity of myocytes by the same percentage prolonged ICT by 73 %. It is therefore concluded that ICT can be much more prolonged due to depressed contractility than due to conduction slowing. The presented results give an idea of the extent to which ICT can be prolonged due to depressed contractility and conduction slowing and therefore can be useful in identifying the causes of decreased myocardial performance in heart disease.
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Impact of the architectural concept on the energy consumption of heating of the energy-saving residential buildings
Křeček, David ; Hudec, Mojmír (referee) ; Vaverka, Jiří (referee) ; Ing.arch.Lorant Krajcsovics,PhD. (referee) ; Chybík, Josef (advisor)
Human efforts to increase their comfort rise in density of population in congested city areas, rapid growth of traffic and electric smog created due to constantly transforming communication technologies all resulted in an increase of stress in the immediate human environment. All of this, along with frequent reports about changes in global climate, gradually contributes to an alteration of thinking of the whole society, which is forced to face the consequences of economic damages caused by climatic changes. If we want to tenably assert adequate economic and social living conditions, we have to approach the natural environment in a more profound way. In accordance with the trend of substantional development for the purpose of enhancement of the quality of the living environment in the field of building industry, it is logical to concentrate on buildings, which are conceptually focused on saving of the energy. That is on energy-efficient houses. Pathway to sustainable building is not based on discovering one or several multipurpose technological solutions, but on usage of new designing principles, new materials and methods of processing them as well as new techniques of construction. For an effective creation of a building concept it is essential to have that kind of device which quickly responds to changes performed on a design, enables an easier work on variants and produces the most accurate results. Consistent application of energy optimizing methods is necessary particularly for designs of energy saving houses. Beginning efficient building design is the most “abstract factor of concept linked with very uncertain inputs,” because a lot of parameters in that moment is still unknown. Many mutually connected factors are invoked during designing passive house e.g. trajectory of the sun and the shielding effect of the surroundings, the aspect of sunlight and interior lighting, power quality construction, etc. Currently, the architect has no choice, he can use only well-known precepts, such as large windows are facing the South not the North. Unfortunately this "empirical formula" for the design of a real passive house is not enough. And yet the first draft of the house is most affected by not only its shape, form, but user´s comfortable, cost, feasibility and future energy behavior of buildings and related operating costs of the house too. It is obvious that this stage should not be underestimated, because “minor variation of the initial inputs greatly influence the outcomes.” With this reasoning, the work focuses on early stage design decision, i.e. the architectural concept of a passive house (an idea, vision). Therefore the aim of this work is to simplify the issue into understandable form, i.e. the creation of relatively simple and illustrative sketches, which generalize the issue satisfactorily, show the individual parameters (glazing, shading, shape, size, etc.) and change need of heat for heating passive house. The results of the work will be useful when the architect picks up the pencil and starts to think about his future house. At this point, he will have on hand sketches, which give him an idea and streamline his further design. Therefore the main goal is to create new outcomes and identify energy behaviour of buildings with a computational tool. This research works with virtual idealized mathematical model in the software PHPP 2007 CZ and uses "phenomenon" of parametric equations and sensitivity analysis.
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Water soluble foundry binders with heat hardening
Vaverka, Jiří ; Rusín, Karel (referee) ; Cupák, Petr (advisor)
This thesis is focused on water soluble foundry binders with heat hardening. The thesis comprises general description of moulding mixtures, the description of the most common methods used for heat hardening and primarily the list of current and alternative binders, which reduce negative environmental impact of foundries. Also their qualities, benefits and drawbacks are included.
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Technological design of a manufacturing process modernization
Vaverka, Jiří ; Dvořák, Jaromír (referee) ; Kalivoda, Milan (advisor)
The topic of this thesis is to design the modernization process. The aim of this work the design of new machines for a particular component, which would replace the existing ma-chinery used in company-tion in which the component is produced. Introduction is focused on the description of the company and selected components for which it is evaluated di-mensioning, tolerance, functionality and material. The following describes the current ma-chinery engineering company and then are selected machines in two variants, which would replace the original equipment. With these new machines is a technical documentation and is evaluated modernization and environmental concerns. At the end of the re-evaluated results that modernization is beneficial or not.
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