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Friction Modification within Wheel-Rail Contact
Galas, Radovan ; Meierhofer, Alexander (referee) ; Pfaff, Raphael (referee) ; Hartl, Martin (advisor)
Předložená disertační práce se zabývá experimentálním studiem modifikátorů tření a maziv pro temeno kolejnice, které jsou aplikovány do kontaktu kola a kolejnice za účelem optimalizace adheze a redukce hluku. Hlavním cílem práce bylo objasnit vliv aplikovaného množství a složení těchto látek na adhezi v kontaktu. Hlavní pozornost byla věnována zejména potencionálním hrozbám souvisejících s kriticky nízkou adhezí, která může nastat po aplikaci těchto látek. Experimentální studium probíhalo v laboratorních i reálných podmínkách, konkrétně v tramvajovém provozu. V případě laboratorních experimentů byl využit komerční tribometr a dvoudiskové zařízení umožňující simulovat průjezd vozidla traťovým obloukem. Kromě samotné adheze bylo při experimentech sledováno také opotřebení a míra hluku. Výsledky ukázaly, že maziva pro temeno kolejnice jsou schopna poskytovat požadované třecí vlastnosti, nicméně jejich chování je silně závislé na aplikovaném množství. V případě předávkování kontaktu dochází ke kriticky nízkým hodnotám adheze, které vedou k výraznému prodloužení brzdné dráhy. V případě modifikátorů tření bylo ukázáno, že chování těchto látek je výrazně ovlivněno odpařováním základního média. Výsledky také ukázaly, že nadměrné množství částic pro modifikaci tření může způsobit kriticky nízké hodnoty adheze. U obou výše zmíněných typů produktů byl prokázán pozitivní vliv na míru opotřebení a míru poškození povrchu, zatímco významná redukce hluku byla dosažena pouze v případech, kdy došlo ke značnému poklesu adheze. V závěru této práce jsou uvedena doporučení pro další výzkumné aktivity v této oblasti.
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Vehicle data analysis
Starý, Přemysl ; Porteš, Petr (referee) ; Zháňal, Lubor (advisor)
The diploma thesis deals with a data analysis of the Formula Student race car. An attention is given for both, vehicle and driver. Processes of braking, turning and balance of car are analysed. Special attention is given to the dampers positions while driving and their settings. Dampers velocity histograms and ride frequencies graph are put together. Algorithms in MATLAB are suggested to reduce requested time for analysis. Scripts for displaying important channels are made. Analyzed data are used to create events which accelerate orientation in record and tell the most important information.
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Design of brake test pedometr
Pavlík, Vojtěch ; Blaťák, Ondřej (referee) ; Vančura, Jan (advisor)
This bachelor thesis is focused on equipment used for measurinng the handling force of braking system, a regulations of homologation tests (by ECE) and inspection checks (by MT) of braking systems. Furthermore, it includes a survey of commercial pedometers and their working principles, its andvanteges and disadvanteges. To end with, the author presents custom pedometer with a calibration device.
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Problems of the Expert Analysis of the Vehicle Movement and Braking Action in General Spatial Curve at Speed Higher than 50 km/h
Panáček, Vladimír ; Šachl, Jindřich (referee) ; Drahotský, Ivo (referee) ; Vémola, Aleš (advisor)
The present apparatus for the technical analysis of road accidents has no well-integrated information, recommendations or procedures of how to solve comprehensively the analysis of road accidents involving vehicles equipped with stabilization system of driving dynamics. The problem in the investigation of a vehicle movement in a curve is the ignorance of the contributions of vehicle dynamics intervention of the electronic stability system. Although some of the simulation software used in the analysis of road accidents makes it possible to take into account the modelled vehicle movement impacted by a stabilization system in the examined process, but the experts do not know what parameters should be entered in the numerical models of stabilization system in a computer programme. Therefore, the thesis investigates the issue of the expert analysis of vehicle riding and braking in a general spatial curve at speeds exceeding 50 kph with simultaneous examining the impact of electronic stability system chassis on vehicle driving dynamics. The thesis first deals with the solutions based on classical analytical methods, then dwells on experimental measurements in real conditions on testing grounds and, finally, addresses the use of computer simulation software in expert practice. Nevertheless, it is important to realize that no computer simulation software can be an absolutely unambiguous solver, and it is not enough to generate a computer simulation, but so obtained results should be evaluated and justified technically. Road accident analyst needs to know the impact of vehicle electronic stability control systems on vehicle movement. The thesis investigated the mutual relationship between the vehicle speed limit in a curve specified by analytical calculation and the vehicle speed in a curve experimentally detected by measuring the parameters of driving dynamics of a vehicle equipped with electronic stability system. The impact of selected electronic stability control systems of the chassis on the vehicle movement in the investigated processes in the curve was detected and quantified by driving experiments. Finally, the input values of significant quantities of computational models of the ESP simulation programs were found consistent with the results of experimental measurements in defined curves for the vehicles equipped with electronic stability systems. The results of the thesis can be used both in the expert and in the teaching activities.
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Measuring the Deceleration of Trucks up to 12 Tons of Weight with the Use of Engine Braking
Kašparová, Hana ; Sedlák, Jaroslav (referee) ; Bradáč, Albert (advisor)
This thesis deals with braking effect of the truck’s engine. The theoretical part introduces the reader to the basic construction of trucks, describes most using engine and defines the factors having a significant effect on engine braking. In the practical part the reader is familiar with the technique used in making the measurement and description of the vehicle chosen for the implementation of measurement. The result of the practical part is the values obtained by measurement including their interpretation contained in the conclusion.
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Analysis of Driving a Passenger Vehicle with a Trailer
Šujan, Tomáš ; Kropáč, František (referee) ; Vémola, Aleš (advisor)
The subject of this thesis is the analysis of the negative effects associated with the operation of a trailer for a personal vehicle with respect to the design speed, technical checks and analysis related legislation. Its work is drawn from the measurement, cooperation with leading Czech production plant trailers Vezeko s.r.o., an organization engaged in the implementation of engineering controls DEKRA Automobil a.s. and available literature, including electronic resources. Results of the work end with proposals for specific measures to minimize the identified adverse effects.
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Quadbike (ATV) Driving Behaviour
Příplatová, Miroslava ; Krejsa, Ivan (referee) ; Semela, Marek (advisor)
This thesis deals with Quadbike (ATV) driving behaviour. This work describes the construction of ATVs, driving behavior and specifications ride them. In this work was performed measurements of braking, acceleration tests, measurements of transverse movement ATVs and subsequent analyse of obtained data. The measured values can be used for working forensic experts and analysts accidents.
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Aircraft Braking Systems
Bulko, Martin ; Koštial, Rostislav (referee) ; Bencalík, Karol (advisor)
The bachelor thesis focuses on problems of braking of aircraft. It describes constituent systems of braking and explains on schemes their function and application. It mentions main advantages and disadvantages of these systems with their subsequent comparison. The thesis includes a summary of braking systems which are used by commercial airplane with capacity over a hundred passengers. There is also analyzed development of braking force size of these airplanes.
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Motorcycle Dynamics Testing
Dolák, Jindřich ; Porteš, Petr (referee) ; Ramík, Pavel (advisor)
The contain of this work is to make suggestion of dynamic tests of motorbikes. I included my owns tests and results. I chose this theme because motorbikes are my hobby. I was really interested in these tests and what will the results turn out. The main part of this theme is to get the necessary values to compare dynamic parameters of motorbikes for braking and acceleration .
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