National Repository of Grey Literature 126 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
NVH Analysis of the Powertrain
Mrózek, Jan ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This master thesis is focused on the diagnostics of vibrations and noise of an internal combustion engine. The work also includes a summary of the current state of knowledge in which the quantities used, transmission paths, measuring devices and the possibilities of performing frequency analysis are analysed. As part of the technical experiment on which this work is based, vibrations and noise on the tractor engine are measured. The obtained data are then further processed using the BK Connect program. Subsequently, a frequency analysis is performed, specifically an order analysis. The conclusion of the analysis consists of an evaluation of individual orders that cause excitation that occur in the investigated motor.
Design of the Gear Coupling for Railway Vehicle Application
Pelíšek, Vojtěch ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
The aim of this work was to create a design of a gear coupling for railway vehicle application. The work presents a comprehensive view of this issue. First of all, a brief theoretical introduction to the issue is made. The practical part follows, where the design of the whole coupling and especially the newly designed solutions are described in detail. The strength analysis performed deal with the key components that are necessary to ensure safe operation. These analyses can be applied not only for this particular case, but also to gear couplings of different designs, because in principle these calculations do not differ much. In the last chapter, which deals with the dynamic model, all the theoretical assumptions are verified, especially the coupling movements and the applied loads. If the reader deals with the issue of gear couplings, not only in the railway industry, this work presents a comprehensive view of this component. The designed coupling and all performed simulations are really usable in operation.
Methods for the wear determination of a railway wheel
Čížek, Petr ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This bachelor thesis deals with the problem of measuring the wear of railway wheels. Railway wheels are subject to high loads and therefore their profile also suffers from high wear. Early exposure of a damaged wheel can prevent fatal train accidents, and hence there is a need to measure wear not only periodically in laboratory but also in during train operation. Wear measurement methods are currently divided into 3 types, the most developed of which are the on-track and laboratory measurement methods. On-train measurement methods are in most cases only at the study stage due to the difficulty of their application to the train set.
Design of a Unified Mechanism of Shifting and Activation of the Parking Brake
Hagara, Adam ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This bachelor thesis deals with the design of a unified mechanism of shifting and activation of the parking lock. The theoretical part is devoted to a more detailed description of the current shifting mechanisms, synchrosystems and parking lock mechanisms. The practical part starts with the analysis of the movements and positions of the individual mechanisms, followed by conceptual designs and the selection of the most suitable one. This is followed by the final design elaboration, which includes the development of a force analysis and torque calculations. The functionality of the geometry of the designed mechanism is verified by dynamic analysis, while the other components of the mechanism are detailed. Finally, an FEM analysis of the components of the unified mechanism is performed to confirm the functionality of the selected design. The thesis also includes a drawing documentation attached in the annex.
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.
Possibilities of structural design optimization
Kopeček, Pavel ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This work deals with issues related to the optimization of structural designs. With the increasing demands of the industrial world, the number of types of optimization is growing, which aims to make the proposed component as advantageous as possible within the framework of various approaches. Due to the more advanced computational complexity, various numerical solvers are used for these optimizations, which facilitate and speed up the whole optimization process. One of the possible solutions to the outlined problem is the use of the Ansys Workbench program, which is the subject of this work. The optimization that was selected for avialability in the Ansys Workbench student license is called topological optimization. This is the process by which a new part shape is achieved for components that are subject to load in the operating state. The new component has a lower weight and sufficient rigidity so that the limiting material characteristics are not exceeded, which would lead to a design, the implementation of which would be dangerous. The advantage of a new component with sufficient rigidity and reduced weight is a lower price for the used material. This dramatically reduces the financial demands of the production process in a piece, but especially in series production. The main output of this work is the inclusion of a brief overview of programs usable for topological optimization, a demonstration of topological optimization on elementary components and the implementation of this optimization on a specific structural element for installation in the test state.
Approaches for Modeling the Exact Shape of the Gears
Capoušek, Josef ; Janoušek, Michal (referee) ; Prokop, Aleš (advisor)
The topic of the bachelor's thesis is the modelling an accurate tooth shape profile, with the goal to create parametric model of the chosen type of gear. In the introduction part the basic terms and classification of the gears are summarized. The following is the overview of the methods of construction an accurate tooth shape profile including examples in the form of planar involute, spherical involute and octoid profile. In the last section the methods of the modelling bevel gear, and creation of the model gear manufactured by Cyclo-Palloid method are described.
Determination of transmission error at bevel gear
Fraňová, Zuzana ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This master’s thesis deals with the determination of the transmission error in spiral bevel gears and its minimization using tooth profile modification in order to reduce vibrations and noise of transmission systems. Gears are the primary source of vibrations transmitted through the shaft and bearings to the gearbox housing and adjacent surfaces that emit noise into the surrounding space. In order to increase the level of comfort and due to the legislative requirements, increasing emphasis is being placed on reducing the noise and vibrations of machine components, including transmission systems. This leads to the need to identify noise sources and evaluate them in terms of expected acoustic performance. The quality of the gear meshing can be judged by transmission error that is closely related to the noise and vibrations. To evaluate the quality of gears based on transmission error, experimental measurements are used that are costly and require quality equipment. Therefore, it is efficient to determine the expected transmission error already at the design stage using numerical methods. In this work a parametric model of bevel gear geometry and a numerical model for the simulation of gear meshing using FEM software Ansys Mechanical are created in order to determine the transmission error. Based on the transmission error, various load cases and gear modifications designed for transmission error reduction are compared.
NVH of gearbox housing for electric vehicles
David, Jan ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This master’s thesis deals with determination of NVH parameters of the gearbox housing for electric vehicle. The introduction part is focused on the theoretical knowledge of this issue. Subsequently, the deviations of geometry on the gearbox were measure by 3D scan method. The next part of thesis is focused on the modal analysis, which is solved by numerical approach and followed by experimental verification. During the numerical calculation solving, the influence of the screw preloading on the modal properties of the structure, was also taken into account. Numerical harmonic analysis was then performed and the results were compared with the experimental approach. The conclusion is devoted to material damping and comparison of the individual results.
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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