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Development of turbochargers
Zogata, Filip ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This bachelor thesis deals with the development cycle of a turbocharger. When we are developing complex components, which completely include the turbocharger, it is necessary to use a number of technical experiments, both testing on a physical model and using computer programs. The aim of this work is to create a basic overview of the requirements for the development of turbochargers, then to approach the use of numerical simulations and testing at gas stations. This work also mentions current trends in this industry based on published studies from recent years. In the final part, the calculation of the modal analysis of the turbocharger is performed using two approaches.
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Design of direct shift gearbox
Kliš, Vojtěch ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with the conceptual design of a double clutch gearbox and the inspection of selected designed parts of this gearbox. The first part of the thesis is focused on the theory of automotive transmissions and analysis of already available double clutch gearboxes. The following is the conceptual design itself, which is based on the selected vehicle on which the transmission will be located and on driving resistances. Based on these default values, the gear graduation is selected, which affects the vehicle’s driving dynamics. With regard to the installation space, a conceptual arrangement of the gearbox is proposed. Furthermore, the thesis is focused on the basic design and calculations of individual functional components of the gearbox. The last part of the thesis is involved to the control of selected structural nodes using the finite element method in the ansys workbench software. The whole thesis describes the individual steps for the design of the basic concept of a double clutch gearbox and the design of their basic components.
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Computational Modeling of Gear Mesh Engagement Dynamics by MBS Approach
Pykal, Vojtěch ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This master’s thesis is focused on the compilation of a computational modelling of gear mesh engagement dynamics of a spur gear by MBS approach. The user input is the specific geometry of gears, the operating speed, and the load torque. The output are the forces in the gear engagement and the reaction of the forces in the wheel bearings depending on the change in the stiffness of the gear due to the changing number of teeth in the engagement and the change in the axial distance. This model is characterized by a fast and relatively accurate calculation in the time domain. This means that it can react to changes in parameters during simulation such as axial distance, speed, and torque.
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Design of direct shift gearbox
Kocman, František ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with the conceptual design of a dual clutch gearbox and with inspection of selected parts of this gearbox. The introductory part is devoted to their theoretical description and subsequent analysis of current dual clutch gearboxes. Then the work focuses on the conceptual design itself, which is based on the chosen vehicle. On the basis of these inputs, the gearbox gear ratios are chosen, which have impact on the economy of the vehicle operation. With respect to the installation area, its conceptual layout is then proposed. Furthermore, this thesis deals with the basic structural design and calculations of selected functional parts of the transmission. The last part of this thesis is devoted to the inspection of selected structural nodes using the finite element method. This whole thesis describes the individual steps of the basic conceptual design of the dual clutch gearbox and the design of their basic components.
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Test Rig Design Proposal for the Experimental Validation of Transmission Parameters in Closed Loop Torque Condition
Otipka, Václav ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
The thesis deals with the design of the experimental testing rig. Test rig is designed to measure NVH transmission parameters. First, basic knowledge of vibro-acoustic measurement is discussed. This is followed by an evaluation of the most commonly used power devices to derive real loads on measured gearboxes. In more detail, a back-to-back test rig is disassembled among other things. In the thesis are described two main components, which are composed of a connecting element and a test bench. Both components were optimized during the design due to their modal properties. Numerical modal analysis was performed in ANSYS Workbench software. The thesis also includes strength calculations performed using both numerical and analytical approaches. The indispensable result of the design work is the complete drawing documentation. Finally, measurements of vibrations and noise on the physically made connecting element assembly have been performed and subsequently evaluated.
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Design of a test condition for determining the wear at the contact of a railway wheel and rail
Rec, Matouš ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This diploma thesis focuses on the issue of a wear of a railway wheel and a rail. The wear of the components depends on a number of parameters including the contact stress, the contact pressure and the contact surface dimensions. Among the factors determining these parameters belongs primarily the wheel driving gauge, the rail profile and the load of the contact area. Furthermore, the material from which the wheels and rail are made, the roughness and hardness of the functional surfaces and the residual stress in the material have a significant impact on the wear. All the parameters mentioned above are designed for the production of the railway wheels and rails and therefore they meet the standards for the production of these components. However, the existence of the changeable parameters has also a significant impact on the wear. These parameters include the presence of contaminants, or lubricants in contact, the changing driving gauge due to the wear, the slip ratio or the friction coefficient. With the wear being an inevitable process during the application it cannot be eliminated but only controlled. Applying the lubricant into the contact when passing through the arc in order to achieve an ideal coefficient or the maintenance grinding for restoring the driving gauge can serve the purpose. If properly optimized, the importance of the wear research lies in the financial savings. Being the crucial factor for optimization of the intervals between the maintenance grinding, the research is also beneficial. A high-quality wear prediction can be seen as the key field in order to increase the safety of the railway vehicles operation as well. Therefore, the wear research is made using several methods, such as the computational models, the multi-body dynamics software and the technical experiments. This thesis introduces a conceptual design of the test, enabling the wear research via experimental approach. The final device is capable of a simulation of both volume and fatigue wear during the states the railway wheel and railway undergo including riding on the straight track, passing through an arc or a wheel slip during braking.
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Sound power level estimation principles
Fajt, Jakub ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This Master´s thesis deals with principles of determination of the sound power level. At the very beginning there is an explanation of important concepts. Afterwards there is an overview of standards that deal with the sound power level determination, including the ČSN EN ISO 9614-1 standard which is used for the experiment. Last but not least, there is described the experiment, consisting of several measurements of the same object, but every time with different configuration of measuring and sound reflective surfaces.
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Determination of transmission error at helical gear
Czakó, Alexander ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This diploma thesis primarily deals with the transmission error issue which is one of the dominant sources of vibration in gear pairs and transmission systems. The vibrations subsequently generate noise which is often subjected to increasingly stricter demands across the industry, including the automotive one. It turns out that reducing the peak-to-peak value of the transmission error has a beneficial effect on the vibro-acoustic properties of gears and gear pairs. This thesis aims to determine the transmission error under static conditions, since a gear pair with a low static transmission error is a good assumption for a low transmission error even under dynamic effects. The resulting values of the transmission error can be influenced already during the design of the gear macro-geometry. It is also suitable to apply micro-geometric adjustments – modifications to the gear teeth. For this reason, the search part of the thesis is dedicated to theoretical knowledge, especially concerning the geometry of gears, modifications of teeth and the overall transmission error and its determination. The transmission error can be determined in several ways, including a technical experiment. However, due to time and financial reasons, this is not always possible, and therefore, the possibility of using numerical simulations is offered. In this thesis, the approach using stress-strain quasi-static contact analysis using the finite element method in Ansys Workbench software is used. The advantage is, among other things, a good comparability of results. The input to the FEM analysis is 3D CAD geometry – in this case, it is specifically a helical gear pair with parallel axes. The model/assembly of this gear pair is created in PTC Creo software fully parametrically, so it is possible to generate arbitrary gear pair configurations by changing the input parameters, which significantly saves time. At the end of this diploma thesis, the stress-strain analysis of various gear configurations is evaluated, with respect to the equivalent stress and contact pressure. Furthermore, the static transmission error – its graphs and peak-to-peak values – is determined from FEM analyses for different gear geometry, including tooth modifications, and for various loading torques. Last but not least, the effects of contact/overlap ratio and centre distance are evaluated.
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Construction of full suspension bike
Trnčík, Tino ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
Bachelor thesis is mainly focused on creation of literature research of currently used rear suspension designs of mountain bikes. However, if we want to divide and compare individual designs, we have to understand which factors affects construction designs and therefore final kinematics characteristics of bicycle. And why some of the properties are essential with one design and with the other not so relevant. Subsequently, we tried to link theoretical knowledge with reality using numerical simulations of rear suspension of individual designs and compare their behaviour. With these simulations we decided to render leverage ratio curve and rear axle path and compare their values with theoretical ones, which each design should reach.
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Noise in rail transport
Maňák, František ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This bachelor's thesis is about the noise of the rail transport, this thesis is focused on the noise, that is generated by trains on the track. This thesis includes analysis of dominant noise sources from rail transport, factors affecting noise and noise measures, which minimize noise from the rail transport as effectively as possible. These measures can be divided into active and passive, each measure has its own advantages and disadvantages. The conclusion describes an evaluation of current trends and considers the future possible development of noise measures.
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