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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Lávka pro pěší podporovaná kabely / Cable-supported pedestrian bridge

Knotek, Jan January 2019 (has links)
The subject of this diploma thesis is design a cable-supported pedestrian bridge. Three different variants of the solution were created for the design. For detailed processing, variant no.2 was chosen - a suspended bridge with a pylon in the middle of the span. The main task is the static design of the supporting structure. The model for the lengthways is created in ANSYS. The SCIA engineer was used to solve crosswise. The assessment and dimensioning was done according to the limit state principles and valid standards.
22

Ověřování věrohodnosti měřicí metody z oblasti modální analýzy / Modal analysis experimental method verification

Pop, Miroslav January 2019 (has links)
This diploma thesis deals with the issue of operational modal analysis, which is one of the newer areas of structural dynamics that makes it possible to estimate modal properties of structures directly during their operation. The aim of this work is to create theoretical basis of operational modal analysis, more specifically of Frequeny Domain Decomposition method. Furthermore, apply this method to a selected structure and verify the achieved results using computational modelling and experimental modal analysis. The technique of dividing the experiment to separate measurements using reference sensor was used. Evaluation of the operational modal analysis was performed using self-created function for the MATLAB software and using the commercial PULSE Operational Modal Analysis software. Obtained results were verified by computational modelling and experimental modal analysis.
23

Analýza vlivu lisovací síly plechů rotorového paketu na kritické otáčky elektromotoru / Analysis of the rotor packet prestress on the rotor critical speed

Lekeš, Filip January 2020 (has links)
The presented diploma thesis deals with the modeling of the rotor packet in dynamic calculations and analysis of the influence of the packing pressing force on the critical speed of the electric motor. The thesis can be divided into three main parts. The first part discusses the current level of rotor packet modeling in dynamic calculations and also deals with analytical theories for subsequent experimental tests. The second part describes the implementation of two experiments to determine the equivalent modulus of elasticity. The first experiment is a four-point bending test and the second is an experimental modal analysis. The third part is used for comparing the results obtained from experimental tests and describes the calculation of the critical speed of the rotor package pressed on the shaft by the finite element method.
24

Lávka pro pěší přes rychlostní komunikaci / Footbridge across the expressway

Páleník, Petr January 2013 (has links)
The aim of this master thesis is a design of the pedestrian bridge across the highway. The bridge is formed by a slab structure of 6 spans with lenghts from 9 to 51 m. The main spans are suspended on a V shape pylon. The deck of the span across the highway is assambled of precast segments and composite deck slab. The deck is in the lenghtways kept in the parabolic arch. The model of the construction is made in software ANSYS, the solution was done non-linear. The design and assessment are according to the europien standard.
25

Dynamická analýza mostní konstrukce / Dynamic analysis of bridge construction

Kinclová, Radka January 2015 (has links)
The objective of this diploma thesis is a dynamic analysis of a cable-stayed walkway. The RFEM structural analysis software is used for the calculation. Design principles of the structure are explained and analysis of the construction phases is then performed. The eigenmodes of the structure are calculated for various material combinations. The thesis examines the effects of moving loads and earthquake effects using several different methods. A comparison of the various loading effects on the structure and also the calculation methods is presented at the conclusion.
26

Vlastní tvary vírového proudění / Eigenmodes of the swirling flow

Jízdný, Martin January 2011 (has links)
This thesis deals with study of dynamics of the swirling flow. The swirling flow occurs frequently in hydraulic machinery (e.g., vortex rope in draft tube of the hydraulic turbine) and often influences operation of these machines. For this reason, sufficient knowledge regarding this characteristic flow is necessary for subsequent improvement of hydraulic machines. The theoretical part of this thesis contains description of flow instabilities and their manifestations, notably Kármán vortex street and vortex rope. In the next part, two methods are applied to these two transient flows in order to identify their specific dynamic properties. The first method, Fourier transform, enables to find frequencies of transient flow. The second method, proper orthogonal decomposition (POD), enables to identify planar or spatial eigenmodes of a specific swirling flow. Proper orthogonal decomposition is used in this thesis to identify planar eigenmodes of Kármán vortex street and spatial eigenmodes of vortex rope.
27

Vytvoření databáze tuhosti statorových svazků elektrických strojů točivých / Creation of database of stator core stiffness of rotational electrical machines

Podzemný, Zdeněk January 2013 (has links)
In this thesis is wrote up a complete procedure of stator core stiffness determination using finite element method (FEM), subsequently, the stator core stiffness database was created according to this procedure. In the next chapter is carried out a sensitivity analysis of one chosen stator core, which led to identifying parameters that affected its stiffness the most. Finally, a modal analysis of one synchronous machine was performed using FEM, in order to determine the effect of stator core stiffness on modal characteristics of the machine. Several modal shapes and corresponding natural frequencies were computed in this analysis, then only a few shapes with the highest core effect were chosen and compared.
28

Porovnání výsledků modální analýzy desky plošných spojů dosažených výpočtovým a experimentálním modelováním / Printed Circuit Board Modal Analysis Results Comparison from Experimental and Computational Modeling

Oplt, Tomáš January 2015 (has links)
Modal analysis of printed circuit board results, gained from computional and experimental modeling, have been compared. Anylyses have been performed on dummy boards (models without electronic components), created as one-layered at first, then as three-layered PCB. Board is usually clamped by its longer edges with wedgelock. In order to enable the realization of boundary conditions in computional and experimental modeling, real clamping has been simplified to simply supported. Computional models have used FEM elements, which are comomnly used in this type of problem. Determined results have been evaluated by comparing the experimental modeling results. Models‘ sensitivity on modification of element length and number of elements through thickness have been performed.
29

Dynamická analýza konstrukce zatížená seismickým zatížením / Dynamic analysis of structure with seismic loads

Šnajdárková, Jana January 2016 (has links)
This thesis focuses on creation of two models of high-rise construction - beam and shell. A dynamic analysis is performed on these models. The selected program is RFEM software and the created high-rise construction is Hearst Tower skyscraper, which is interesting for its diagrid system around its perimeter. There is described process of creating both models and associated problems. Dynamic analysis is performed using standard EN 1998-1. There belongs calculations of sufficient number of modal shapes, spectral analysis and time analysis. Then the results are compared on selected point on the both models.
30

Specifika češtiny ruských studentů (se zaměřením na vybrané fonetické a morfosyntaktické jevy) / Characteristics of the Czech language of Russian students(with a focus on selected phonetic and morphosyntactic phenomena)

Ramasheuskaya, Katsiaryna January 2015 (has links)
Language adaptation of foreigners is always accompanied by a number of problems connected to the acquisition and the use of the language which becomes the primary communicative tool in the new environment. Ignoring and underestimating these problems typical of a particular language community can result in a failure to master the target language and consequently in the unsuccessful integration in the new society. This thesis is aimed at specific problems in the area of morphosyntax and phonetics, characteristic of Russian-speaking students of Czech. At the same time, it warns about the danger of overestimating positive transfer from Russian and emphasizes the necessity of using special didactic approach in teaching this group of foreign-language speakers. The analysis of the chosen language phenomena is based on the data from the Database of the voice recordings of spoken Czech by native speakers of Russian and the Database of language mistakes in Czech made by speakers whose native language is another Slavic language, which were created, among others, for the purpose of this thesis. The attention is specifically focused on the use of the reflexive se/si, forms of the auxiliary verb to be in the past tense, short forms of personal pronouns in spoken and written production of Russian-speaking...

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