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NVH problematics at vehicle testing on chassis dynamometer
Jiříček, Martin ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This bachelor's thesis deals with noise and vibration issues in vehicle testing on a chassis dynamometer. It aims to provide an insight into the field of chassis dynamometers, their design and function, to provide an overview of the possibilities of vibration and noise measurement on vehicles and to explain the possibility of using the chassis dynamometer as a measuring device for a complete noise and vibration analysis, including an evaluation of its advantages and disadvantages based on available studies and literature.
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Machining of long cylinders
Nádvorník, Vít ; Jaroš, Aleš (referee) ; Fiala, Zdeněk (advisor)
The bachelor thesis deals with the machining of long cylinders and production machines used for the machining technology. The main part contains a description of the vibration system of machine-tool-workpiece and analyzes active and passive methods of its elimination. It also deals with the wear of the cutting tool and a description of the parameters which have a direct effect on tool life.
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Vibration of faulty bearing depending on the load
Slaninová, Barbora ; Marcián, Petr (referee) ; Krejsa, Jiří (advisor)
The subject of the presented bachelor thesis is an analysis of a bearing vibration during its failure on inner race with varying load. The work aims to create a model simulating the time course of vibrations in the event of a bearing failure depending on the load and speed of the bearing. The work compares the frequency and time model of the rolling bearing error spectrum. A model of bearing error frequencies was also created, which is supplemented by a force action in the next step. To parameterize the model, data were experimentally measured on a bearing that takes on three possible states. The first bearing has a defect on inner race measuring 0.25 mm, the second bearing 0.5 mm and the third is free of defects. The measurement takes place on a test bed in 135 repetitions. Inventor is used to design the bearing with defect. The measured data are processed and visualized with MATLAB. The measured values show that the rate of vibration is not only dependent on the load and speed, but also the size of the defect.
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The analysis of dynamic effects in the frog region of railway turnout
Balash, Arsen ; Pazdera, Luboš (referee) ; Smutný, Jaroslav (advisor)
This thesis is focused on measurement and analysis of dynamic effects on railway turnouts. Two same-type turnouts with different fastening elasticity were chosen. My attention was focused mainly on the crossing part of the turnout, where the highest dynamic impacts occur. The point of the thesis is comparison of the crossing part of turnouts in term of dynamic behaviour and assessment of influence of soft rail pads on spread of dynamic energy through the construction. A part of the thesis is choice of methodology of the measurement and proposal of convenient mathematical apparatus for analysing of the dynamic effects on crossings.
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Usage of transmission at electric vehicles
Běloušek, Ondřej ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
At first bachelor thesis divides different conceptions of electric vehicles with the aim to describe characteristic components which electric vehicles contain, and that make it different in comparison with conventional cars. From the principle of the electric vehicle it is obvious that electric energy which is necessary for electric drive must be stored and for this reason the batteries and important components are described. The next part is dedicated to the powertrain which is affected by the presence or absence of an internal combustion engine and its usage rate. Common feature is an electric machine which transforms electrical energy into mechanical energy, and which makes powertrain complete. Gearboxes used at electric vehicles are the next part which is affected by the type of power unit that they cooperate with. For that reason, one representative from each part is described. The representative of hybrid electric vehicles is planetary gear set of Toyota Prius 2010, representative of battery electric vehicles is one-speed transmission of Tesla cars and in the end the multi-speed transmission is mentioned because it is today´s trend. Because of the absence of an internal combustion engine for some types of electric vehicles, the noise and vibrations from gearbox come to the fore. The main source of the vibration is gears teeth contact and rattle of the other components. The last part of the thesis is focused on the design of a technical experiment that is suitable for measuring vibration and noise from two-speed automatic transmission. Firstly, the theoretical basis of measurement is described. The design itself takes into account the suitable measuring equipment, the right choice of components that realize closed loop and installation space of the acoustic chamber.
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Noise Reduction Methods in Automotive Design
Kubica, Petr ; Janoušek, Michal (referee) ; Prokop, Aleš (advisor)
The aim of this bachelor thesis is create a research study about noise reduction methods in automotive design. The introduction of this work deals with acoustic and the influence of noise on people. Furthermore it deals with ways of noise creation in a car and its suppression. In the end of this work there is a valorization of certain methods at noise suppression of a personal vehicle.
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Noise Reduction Methods in Transmissions
Benda, Matouš ; Zubík, Martin (referee) ; Prokop, Aleš (advisor)
Transmissions are basic elements of cars, which are important parts of everyday life. Expect targeted properties transmissions have a great influence for a total noise emitted by car. This thesis deals with possibilities of reducing this noise. In a first part of this thesis, reader is acquainted with the basic knowledge of acoustics, where are definitions of sound and mentioned noise. Another part analyzes transmission, as a mechanical component formed by smaller machinery units. This description is important for understanding transmission of vibrations in the structure, which further due to vibrate surroundings, which the human ear perceives as noise. These vibrations are mainly generated between meshing gears, and therefore the transmission error, which is responsible for these vibrations is analyzed in the next section. The last part discusses noise reduction methods, partitioned by the transmission components, in which are these methods applied.
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Use of Vibrodiagnostics in Forensic Engineering
Záleská, Veronika ; Bradáč, Albert (referee) ; Panáček, Vladimír (advisor)
This thesis deals with the measurement and evaluation of vibration on selected parts of car. Part of the work is devoted to the theory of vibration and noise, which includes, among others, presentations of common disorders of machine parts in terms of vibration. In the practical part of the work were performed out measurements described here and the results analyzed. Last part is in short devoted to the possibilities of using a similar measurement in forensic engineering.
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Design of the Machine for a Roadside Compacting
Šoltysová, Michaela ; Chorý, Tomáš (referee) ; Rubínová, Dana (advisor)
Subject of this master thesis deals with the concept of the machine for a roadside compacting. After analysing of current market situation the aim of this work is not only to replace the vibration plate by new machine with a cab and vibration rollers but also mainly the design of the machine. The reason is easier work and it fulfils all constructional and ergonomic requirements and puts emphasis on aesthetic. So it fills a gap in the market.
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