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Three-point bending test of foam laminates
Kelecsényi, Matej ; Navrátil, Petr (referee) ; Skalka, Petr (advisor)
The bachelor thesis deals with the formation and the spread of disorder of crossbeams in core of composite, in ceramic foam with homogeneous structure formed by Kelvin cells with open porosity loaded by three-point bending test. The method of finite element in software ANSYS was used for the creation of composite sample calculation model as well as in calculation of sample loads. The results of the thesis are the values of the sample reaction force and of the first main tension on crossbeams of foam core sample obtained by loading of the foam composite sample. The area of breaches crossbeams was inferred from the analysis of composite core structure breach. In conclusion were evaluated the results obtained in this thesis.
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Inverter 12 V DC to 230 V AC with Protection
Navrátil, Petr ; Šilhavý, Pavel (referee) ; Kubánek, David (advisor)
This bachelor thesis deals with converter, which alters 12 V of direct input Voltage to 230 V of alternating Voltage output with frequency of 50 Hz. Introduction describes the basic parting of convertors. The chosen concept of designed convertor was based on that chapter. The practical part describes construction of this convertor including necessary safety shielding. At the end, the construction of the converter was tested by practical measuring and it was proven that the result meets with required values with slight anomaly.
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Modelling of the randomly formed ceramic foam structure for FEM simulations
Papšík, Roman ; Navrátil, Petr (referee) ; Ševeček, Oldřich (advisor)
This bachelor thesis deals with construction of ceramic foam model with various levels of (ir)regularity for finite element simulations in Ansys. The main objective is to substitute the complex structure of the open cell foam using the beam elements, enabling to perform FE analysis on much larger volumes of foams than the realistic foam models composed of solid elements. In this work, the technique of the model creation is based on the Voronoi tessellation and enables choice of arbitrary (ir)regularity of the modelled structure. The created source codes generate the model data directly in the syntax of APDL language for FEM system Ansys. The first part of the work describes several methods of the space partitioning and methods for substitution of the real foam structure by simplified “wire” model. The second part defines the Voronoi tessellation (diagram) as a key technique for creation of the foam model and describes its algorithms. The next part of the work deals with possibilities and utilizations of various software and libraries, describes creation of the own code in mathematical software Matlab and way how to transfer the model data into the system Ansys. The last part of the work demonstrates functionality of the created model on several FEM simulations, studying response of the ceramic foam on the external mechanical loading, upon consideration of various levels of the foam structure irregularity.
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Teaching guide for the ATMEL development board
Navrátil, Petr ; Hadinec, Michal (referee) ; Friedl, Martin (advisor)
Bachelor’s thesis is focused on developing applications for the developing board with microcontroller ATMEL (ATmega16). Bachelor’s thesis describes the microcontroller including a description of hardware components and control registers. This book describes the various peripherals on the developing kit with programming examples. Simple modules have been created for the developing board, which could be used to program complex project and easy aplications. On these modules are periphery as matrix keyboard, encoder, real time clock and circuit L293D for controling DC motor with PWM signal. The AVR Studio version 4.18 is described and used here as a programming software. This work should serve as a guide about ATMEL AVR ATmega series for beginning or advanced programmers. Examples of individual programs are a part of this work.
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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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Cleaning of biogas by the PSA (pressure swing adsorption)
Navrátil, Petr ; Houdková, Lucie (referee) ; Leštinský, Pavel (advisor)
The topic of this master thesis is upgrading of biogas. As a mixture of gases produced during anaerobic digestion, contains methane which is highly energy valuable gas. But also other substances that we want to remove. We will present the motivation for upgrading biogas and the possibility of separation, generally the pressure swing adsorption method. The key parameter of this technique is the choice of a suitable adsorbent. This is possible based on the knowledge of adsorption processes, therefore, is also described below. The objective of this thesis is to determine the parameters of the pressure swing adsorption metod. To do this it is necessary to determine the adsorption capacity of the adsorbent, measure breakthrough curves of carbon dioxide and methane, and determine the pressure drop of solid bed, etc. As a result we can finally make a balance and evaluate the applicability in practice.
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Rational process for the testing of powered door operation for rail vehicles
Grulichová, Jana ; Navrátil, Petr (referee) ; Kubík, Roman (advisor)
This master´s thesis focuses on possible rationalization of the testing operations the door drive units of the rail vehicles. The aim is to propose solutions to increase productivity and reduce operating costs. The first section briefly describes the history and basic principles of lean manufacturing. The following is the description of the assembly and testing of the door drive units including the analysis of the current state of testing workplaces. The following section identifies critical areas and reserves that could be used to increase productivity. In next chapters are proposed kinds of rationalization, their evaluations according to the cost of implementation and the possible achieved effects. Chosen variant is elaborated in more details. The last part deals with the economic evaluation and verification of the proposed method in conditions of the real production.
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Rationalization of a manufacturing system at Prodia company
Jakubec, Jan ; Navrátil, Petr (referee) ; Kubík, Roman (advisor)
The work deals with the optimization of the production system in the engineering company Prodia s.r.o. There is a review of technological design in the introduction, the methods of analysis, design methods and capacity calculations are introduced. Subsequently, using these methods, the current state of material flows are analysed, the critical points in the production defined and design of new solution options to eliminate the main weaknesses identified during the analysis. Finally, an evaluation of the best variant and its economic profitability is introduced.
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Optimization of work area at the end of production line where final control checks of cook-stove are conducted
Nábělková, Irena ; Navrátil, Petr (referee) ; Kubík, Roman (advisor)
The subject of this thesis is focused on analysis of three test workplaces for final inspetion of a stove and determination of a workplace most appropriate for optimization. The thesis includes operating instructions of test equipment and test regulations of appliances that are tested on the production line. The analysis of the operation times was based on data measured in the MORA company and led to an idea of reducing the number of electric stoves positions and guaranteeing the same reliability of testing. The re-measurement of data and the comparison of results has been carried out.
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