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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.
1

Návrh sběrnice LVDS s vysokou odolností EMC / Design of the LVDS bus with hight EMC immunity

Klauda, Zbyněk January 2008 (has links)
My thesis deals with project of LVDS busbar with high resistivity with regard to disturbance from surroundings and radiation undesirable electromagnetic waves into its environment. Project of LVDS busbar was elaborated by numeric methods and it was suggested optimal solution of the shape and material of multiply technology DPS. The project was realized on desired driving-point impenance of busbar Z=100 ohm with frequency f1=100 MHz of the first harmonic component rectangular signal of defind modality, entering and diagonal edge.
2

Optimalizace rozměrů základového rámu formy na velké odlitky / Optimization of dimensions of the base frame to form for large castings

Mottl, Jan January 2011 (has links)
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.
3

Návrh a optimalizace ojnice motoru závodního automobilu / Con Rod design and optimization of racing engine

Ulman, Jaroslav January 2010 (has links)
This master thesis describes the design and optimization of connecting rod motor racing car. At the beginning of the whole work is a 3D-model of rods, from which then the whole work is based. Then it analyzes the current model of stress and on the basis of the results are made structural changes to the solution of rods. Newly adapted connecting rod is again analyzed using FEM and newly obtained results are compared with results of the original model of connecting rods. The conclusion deals with sensitivity analysis of selected parameters of rods and their potential effect on the resulting changes in strength connecting rod .Then is an assessment of all results.
4

Vibrationsanalys av vevaxel vid fräsoperation / Vibration analysis of a crankshaft during milling operation

Hartelius, Belinda, Fransson, Philip January 2017 (has links)
Finita elementmetoden (FEM) utvärderas för att i framtiden kunna undvika mycket av den fysiska provning som idag används vid optimering av maskininställningar, både vid införandet av nya maskiner men även på befintliga. Fräsmaskinen som granskas grovbearbetar fyrcylindriga vevaxlar under åtta bearbetningstempon. Resonansfrekvenser skulle kunna identifieras med hjälp av en FEM-modell och sedan undvikas genom att justera skärhastigheten. Litteraturstudien innefattar skärande bearbetning, vibrationer, svängningsteori och FEM. Modeller av vevaxlar ges av arbetsgivaren och egenfrekvensanalyser utförs i programvaran Abaqus för samtliga bearbetningstempon. Egenfrekvenser jämförs med den drivande frekvensen från fräsverktyget. Fräsning i vevaxelns egenfrekvens inträffar vid ett tillfälle, bearbetningstempo två. Vibrationerna antas inte påverkas i stor utsträckning på grund av fräsverktygets differentialdelade skär som gör att fräsning i egenfrekvens endast inträffar var sjätte skär. Vibrationsdata från arbetsgivaren visar även att vibrationerna är låga för bearbetningstempot. FEM-modellerna verifieras med fysiska experiment (slagimpulsprov) på fritt upphängd vevaxel och jämförs med resultat från FEM-analys för fri axel. Skillnaden i egenfrekvens mellan experiment och FEM-simulering är maximalt 5 %, vilket bekräftar modellernas tillförlitlighet. Vidare skapas en förenklad modell av fräsverktyget som analyseras angående egenfrekvenser i Abaqus. Egenfrekvenserna visar sig vara betydligt högre än högsta skärfrekvensen, vilket verifierar att bearbetning inte sker i verktygets egenfrekvens. Finita elementmetoden är en mycket lämplig metod för att fastställa egenfrekvenser och därmed undvika bearbetningsvibrationer som uppstår p.g.a. resonans. Fräsverktygens differentialdelade skär ger dock en ständigt varierande frekvens, vilket tyder på att vibrationerna i fräsmaskinen troligtvis inte orsakas av resonansfenomenet. / The finite element method (FEM) is evaluated with the purpose of avoiding time consuming physical testing which is currently used for optimizing machine settings, both in new and existing machines. The studied milling machine machines crankshafts through eight machining steps. Resonance frequencies could be identified with a FEM-model and then be avoided by adjusting the cutting speed. The literature study includes machining through cutting, vibrations, oscillation theory and FEM. Crankshaft models are provided by the employer and eigenfrequency analyses are carried out with the software Abaqus, simulating the crankshaft mounted in the milling machine during all machining steps. The eigenfrequencies are compared to the cutting frequency from the milling tool. Milling with eigenfrequency occurs during machining step two. The influence on the vibrations is assumed to be small due to the variable teeth spacing on the tool. The machine will therefore only be machining in eigenfrequency every sixth cut. Vibration data created by the employer also indicate that vibrations are low during the machining step. Verification of the FEM-models is conducted through physical experiments with impact hammer testing. The test is carried out on a freely hinged crankshaft and compared to the FEM-results for a constraint-free crankshaft. The difference in eigenfrequency between the impact hammer test and the FEM-analysis is a maximum of 5 %, which demonstrates the reliability of the model. Furthermore a simplified model of the cutting tool is made and analyzed for eigenfrequencies in Abaqus. The eigenfrequencies are shown to be higher than the highest possible cutting frequency which confirms that the cutting tool is not machining in its own eigenfrequency. FEM is a useful method for determining eigenfrequencies and thereby avoiding machining vibrations caused by resonance. However, due to the variable teeth spacing the cutting frequency is constantly changing for the operation, which indicates that the vibrations are not caused by the resonance phenomena.
5

Deformačně a napěťová analýza čelisti se zubním implantátem VNI / Stress - strain analysis of jaw with tooth implant type VNI

Školník, Roman January 2008 (has links)
This diploma thesis is dealt with stress-strain analysis of jowl with teeth implants. Teeth implants when locked in place (jowl) have the ability to replace and be used in the same way as the missing teeth. The implant creates a pillar column in the buccal cavity and then the tooth cap or bridge is secured on the pillar column. In this diploma thesis it is described as a solution of stress and strain of two types of cylindrical teeth implants VNI. Thesis specializes on the influence of deviation implant from the vertical axis. The solution is accomplished in program ANSYS Workbench by Finite Element Method (FEM). The geometric models are made in program SolidWorks 2005.
6

Model komory reaktoru pro mikrovlnný ohřev / Model of the reactor chamber for microwave heating

Kříž, Tomáš January 2008 (has links)
The diploma thesis deals with the concept of a high-frequency chamber which serves for desiccation of emulsion consisted of oil and water where the contents of water is over 30% of the emulsion capacity. The high-frequency chamber works on frequency 2,45 GHz. The task was to design a numerical model in which a high-frequency thermic conjugated problem is solved. The design of a high-frequency chamber is made up considering the heat distribution in inhomogeneous environment as well as chemical and physical changes. The proportions of the high-frequency chamber can guarantee the biggest output transmitted from the source to the chamber with the emulsion desiccated and uniform layout of electromagnetic field. These criteria are necessary for smooth heating of the emulsion desiccated. In this diploma thesis, there were several numerical models with various proportions made up. Finally, the one with the shortest time of heating the emulsion in reference to emulsion capacity was chosen.
7

Návrh synchronního reluktančního motoru / Design of synchronous reluctance motor

Koshelev, Maxim January 2014 (has links)
Master thesis deals with analysis of the definite synchronous reluctance motor with salient poles and design of synchronous reluctance motor with barriers for magnetic flux. The work is divided into five parts. In the first part there is a brief overview of realized synchronous reluctance motor designs and also operating principle of motor of this type is described. The next part contains the basic parameters of the synchronous reluctance motor with salient poles; the parameters were found with analytical calculation. The third part demonstrates verified by means of FEMM results of analytical calculations for linear and nonlinear states and with transient analysis of motor using Ansys Maxwell environment. In the following part results of testing of the synchronous reluctance motor with salient poles are presented as well as the comparation of these results with calculated values and the results of simulations. The closing part of the thesis shows the design of synchronous reluctance motor with barriers for magnetic flux. All obtained parameters were examined using FEMM and Ansys Maxwell. The final version of the proposed motor was analysed when supplied directly by mains and through the converter by Maxwell- Simplorer co-simulation.
8

Analýza dynamiky rotoru asynchhronního generátoru spojeného pevnou spojkou s hřídelí vodní turbíny / Rotor dynamics of asynchronous generator fast fixed with water turbine

Blažek, Petr January 2011 (has links)
This Master’s thesis deals with rotordynamics analysis of asynchronous generator rigid coupling with water turbine shaft. The purpose of this thesis was to determine influence of connection of generator with water turbine by rigid coupling to reactions in bearings. This problem was solved in two ways. The first option focused on model without influence of inaccuracies whereas there were inaccuracies included in the second option. The problem was solved by computational modeling by software Ansys.
9

Deformačně a napěťová analýza čelisti se zubním implantátem BOI / Stress - strain analysis of jaw with tooth implant type BOI

Marcián, Petr January 2008 (has links)
Submitted master thesis deals with stress - strain analysis of jaw, with dental implant. The implant serve as a suitable pillar for crown or dental bridge, when one or more teeth are lost. The project is oriented on BOI (basale - oseo - integrable) dental implant type, which is produced by DENTALIHDE company. Stress – strain condition of the mandible system with implant have been established by computational simulation, with use of the final elements method. Important part of down jowl is simulated on with EDS and EDDS applied types of implants. After implementation the implant begins to heal. Therefore the special attention is paid to stress - strain states on various level of osteointegration. There is a detail description of production of single part computational model and his solving in the master thesis. Presentation of large chapter with results and subsequent alteration stress - strain analysis is part of the master thesis. Program SolidWorks 2005 was used to create the geometric model. Computational model and the actual solving was accomplished with use of ANSYS 11.0 and ANSYS Wor-kbench systems.
10

Návrh rámu horského kola a jeho deformačně napěťová analýza pomocí MKP / Design of mountain-bike crossbar and its FEM analysis

Jelínek, Martin January 2008 (has links)
The aim of this diploma thesis is the part of evolution of the new bicycle frame for mountain biking, category enduro. The first part of this thesis is focused on creating dimensional modified model of the bike frame in CAD system SolidWorks. Subsequently this frame will be detailed by FEM analysis in software ANSYS Workbench and determine boundary conditions for this analysis. The final part is about visualization of the new bike frame.

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