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Stability analysis of swinging props turbines
Bukovský, Petr ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
Master thesis deals with a computing simulation of two props turbines lines. The thesis output is gaining maximum possible load, at which a commencement of deformation stability critical state for various geometrical imperfections has not arisen yet. The calculation has been done by FEM in two different ways: linear solution (using a calculation conversion into eigenbuckling) and nonlinear solution (using a FEM deformation option). Result analysis compares both methods outcomes. Safety factor for the props operation has been proposed taking into consideration known influences on operating state.
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Homogenization of open foam structures using Kelvin cell
Barančík, Milan ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor thesis deals with homogenization of open foam structures using Kelvin cell. A computational model of the foam structure was created and converted into a computational model of solid with corresponding material characteristics in ANSYS software. Subsequently, a parametric study of the effect of Kelvin cell proportions on solid material characteristics was done. The output of the study was a generalization of the dependence of solid material characteristics on Kelvin cell proportions. Lastly, the suitability of the generalization was verified and achievements were evaluated.
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Application of activated carbon in flue gas treatment process
Navrátil, Petr ; Niesner, Jakub (referee) ; Jedlička, Filip (advisor)
The objective of this bachelor thesis is to explain the problematic of flue gas treatment from the air pollutants mainly by methods using adsorption on activated carbon. There is an introduction to environmental protection, description of selected chemicals, charcoal and description of technologies to remove pollutants in municipal waste incinerators, and finally mention the possibilities of disposal or reuse of a saturated carbon. And finally selection of appropriate methods and design for a specific application.
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Stress-strain analysis of clamping mechanism element
Gergeľ, Erik ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor thesis deals with creation of computational model and solves Stressstrain analysis of a car window clamping mechanism element. The main focus of thesis is to locate a critical area of part and find out the distribution of stress is this area. FEA system ANSYS was used for this analysis. The shape optimization based on results of FEA was successful. The equivalent stress was significantly lowered. It would be able to increase the operating time of clamping element.
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Optimization of dimensions of the base frame to form for large castings
Mottl, Jan ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
In this thesis the problem of optimizing the dimensions of the base frame molds for casts with FEM and for 4 weight classes, ie casts weighting 1, 3, 5 and 10 tons is solved. For the evaluation of the FEM ANSYS program was used. There are gradually presented optimization procedures for all four weight classes. There was established the persistence of forms and frame and at the end the conclusion of the technical-economic evaluation of the proposed forms in terms of material savings in comparison to the current state of production was made.
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Crack Propagation in Railway Wheel under Operating Conditions
Navrátil, Petr ; Schmidová, Eva (referee) ; Fuis, Vladimír (referee) ; Janíček, Přemysl (advisor)
This doctoral thesis was written under supervision of my supervisor Prof. Ing. Přemysl Janicek, DrSc. and under supervision of my specialist supervisor Ing. Petr Skalka, Ph.D. The thesis deals with the influence of various operating conditions on crack behaviour in in a wheel rim and/or tire. The dissertation topic was motivated by cooperation with Pardubice University, Faculty of Jan Perner. The first part of the thesis presents a literature search, which provides a current state-of-art in the field of contact loading, crack propagation behaviour under mixed-mode and thermal field generated during braking. The next part of thesis deals with the solution of the given problem and the obtained results are presented. Specifically, crack behaviour under various operating conditions including the crack growth rate is simulated. Also, an influence of thermal field on crack is investigated. The linear elastic fracture mechanics approach is considered to treat the above mentioned problems. Last part of thesis summarizes the obtained results which are discussed in a broader context.
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Determination of mechanical properties of open ceramic foam structure using finite element method
Barančík, Milan ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The thesis is concerned with creating of a computational model of open-cell ceramic foam and determining mechanical properties of open-cell ceramic foam using computational modeling. The geometry of Kelvin cell was used for creating the model of geometry of the foam. The model of geometry of ceramic foam structure was meshed with solid elements, with beam elements and with combination of rigid beam and beam elements. Elastic properties of the foam were determined by two types of mechanical loading. Young´s modulus and Poisson´s ratio were determined by tensile/compressive mechanical loading and shear modulus was determined by shear mechanical loading. The relationship between mechanical properties of the foam and the ratio of diameter of strut D and length of strut L was analysed in the thesis. A good agreement was found out between Young´s modulus determined by solid element based and Young´s modulus determined by modified beam based model of geometry of the foam structure – for ratio D/L up to 0,6. In the case of Poisson´s ratio a good agreement was determined up to D/L = 0,4. In conclusion the value of Young´s modulus 1,97 GPa which was determined by computational modeling was compared with the value 1,56 GPa which was determined experimentally on ceramic foam. This difference was caused by idealization of geometry of the real ceramic foam material. In addition, mechanical properties of the ceramic foam material are influenced by structural imperfections of the material.
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Proposal for technological layout of machines in a milling room of a mechanical engineering company Tirad
Dohnal, Tomáš ; Navrátil, Petr (referee) ; Kubík, Roman (advisor)
Tirad, a metal machining company, plans to build a new hall as an extension of its operation. This paper deals predominantly with production flow analysis of present operation. The analysis draws upon literary study and the company's previous production experience. Possible placement of machines is suggested in the following part of the paper, based on the analysis and requirements of the company. The fundamental requirement is to separate roughing and finishing technological operations, moving the latter completely into the new hall. The deployment of machines is optimized with regard for materiál flow. The new hall's dimensions are outlined in a drawing. Three options of machine deployment are discussed. In conclusion, these options are compared to one another and also to the present state.
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