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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.
221

Friction Modification within Wheel-Rail Contact / Friction Modification within Wheel-Rail Contact

Galas, Radovan January 2018 (has links)
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.
222

Systém common rail pro šestiválcový vznětový motor / Common Rail for Six-cylinder CI Engine

Božik, Michal January 2013 (has links)
This thesis deals with the installation of high-pressure common rail injection system for six-cylinder tractor diesel engine. In the first part of the thesis is dismantled issue injection systems and related aspects. The next part is the installation of a fuel injection system, which involves placing components common rail system, the implementation of necessary interventions in engine design and the design of new components. The final section effect control calculations and stress analysis of new injection system components.
223

Analýza vlivu funkčních parametrů na těsnost nízkotlakého konektoru Common Railu / Analysis of the influence of the Common Rail low-pressure connector parametres on its leak tightness

Ščerban, Bedřich January 2020 (has links)
The aim of this theses is a sensitivity analysis of the tightness properties of the press-fit joined of the fuel pressure vessel Common Rail and the low pressure connector. Possible solutions were analyzed, where the fractional factorial design of a numerical experiment resolution four was chosen. Results of the thesis are statistically significant factors used in formulating the construction change recommendations.
224

Spolupůsobení bezstykové koleje a mostní konstrukce / Continuous welded rail on bridges

Vendel, Jiří January 2012 (has links)
The aim of the dissertation is to compare different analysis of the interaction continuous welded rail and bridge in the domestic and foreign literature and to compare the provisions of the prescription S3 Permanent way structure and ČSN EN 1991-2 (73 6203) Eurocode 1: Actions on structures - Part 2: Traffic loads on bridges.
225

Výroba vodící kolejničky / Manufacturing of guiding rail

Klímová, Jana January 2010 (has links)
Subject of this diploma thesis is manufacturing of the guiding rail HB 02150 made of metal sheets and used for table slide rail in drawer system. This thesis was made in cooperation with Hettich ČR Company which is producer of furniture hardware. Theses contains theoretical part which explains matters of cutting and bending technology. Marginally will be mentioned matters of spot welding. Practical part contains explanation of production of guiding rail, lay-out of bending roll and cutting tools. In this work there is also described solution of problem with wastrels caused by faulty welding of metal sheets and the draft of welding fixture which solves this problem. Economical and technical summary of this manufacturing process is the last part of this thesis.
226

Systém common rail pro čtyřválcový vznětový motor / Common Rail for Four-cylinder CI Engine

Brhel, Štěpán January 2012 (has links)
This master´s thesis deals with instalation of high pressure injection system Common Rail on four-cylinder tractor CI engine. Thesis introduces in the first part the injection systems of CI and tractor engines and related issues. In the next part is solved the conversion of engine, design of most important components - injetor, high pressure pump, pressure accumulator and high-pressure pipes and then stress analysis of new components.
227

Systém common rail pro šestiválcový vznětový motor / Common Rail for Six-cylinder CI Engine

Božik, Michal January 2014 (has links)
This thesis deals with the installation of high-pressure common rail injection system for six-cylinder tractor diesel engine. In the first part of the thesis is dismantled issue injection systems and related aspects. The next part is the installation of a fuel injection system, which involves placing components common rail system, the implementation of necessary interventions in engine design and the design of new components. The final section effect control calculations and stress analysis of new injection system components.
228

Modèle dynamique d'interaction véhicule-voie ferroviaire en présence de défauts géométriques sur les surfaces en contact / Dynamic train-track interaction model with geometric defects on the surfaces in contact

Pecile, Bérénice 31 January 2017 (has links)
Les phénomènes dynamiques observés lors de la circulation des trains provoquent des nuisances, notamment sonores et vibratoires, qui sont amplifiées par la présence de défauts sur la roue et sur le rail. Pour les analyser, il est nécessaire de prédire avec robustesse le comportement dynamique des composants impliqués dans l’interaction véhicule-voie et donc de simuler les efforts de contact générés pour des interfaces non idéalisées.L’objectif de cette thèse est donc de proposer un modèle semi-analytique global compatible avec l’intégration de multiples défauts géométriques sur les surfaces en contact. Afin de simuler l’interaction véhicule-voie dans le domaine temporel et garantir une applicabilité en phase de dimensionnement, une attention particulière est portée sur le compromis entre la précision des résultats et les temps de calcul associés.Le modèle ainsi proposé est composé d’un demi-bogie, dont le comportement vertical est représenté par un ensemble de masses-ressorts-amortisseurs, circulant sur une voie ballastée. Cette dernière est assimilée à une poutre bi-appuyée, supportée périodiquement à l’emplacement des traverses. Ces deux systèmes sont couplés en contact grâce à une procédure Distributed Point Reacting Spring (DPRS) sous forme discrétisée.Une validation du modèle est, d’une part, proposée en considérant des travaux antérieurs dans le cas de géométries parfaites. D’autre part, de multiples combinaisons de défauts, localisés comme le méplat ou répartis comme l’usure ondulatoire, sont introduites dans la simulation. La variabilité spatiale, particulière au cas de l’écaillage, est modélisée par des champs aléatoires. / The appearance of dynamic phenomena during the running of train on track leads to issues such as noise and vibration pollution, which can be further amplified by the presence of defects on the treads. In order to analyze them, it is necessary to predict with reliability the dynamic behavior of the vehicle-track interaction components, in particular the contact forces produced by non perfect treads.The aim of this PhD thesis is to provide a semi-analytical vehicle-track interaction model able to take into account multiple defects on the surfaces in contact. In order to conduct simulations in the time-domain and ensure applicability in the sizing phase, a special attention is given on the compromise between the accuracy of the results and the simulation times.The proposed model is therefore composed of half a bogie running on a ballasted track. This latter is modeled by a pinned-pinned beam with periodic supports located at the sleepers while the vertical behavior of the bogie is given by masses, springs and dampers. These two models are coupled in contact by a discretized Distributed Point Reacting Spring (DPRS) procedure.A validation of the model, based on previous work, is firstly proposed for perfect treads. Then, multiple combinations of defects, either localised as wheelflat or spread as corrugation, are introduced in the simulation. The spatial variability, specific to shelling, is modeled by random fields.
229

Optimization of operative planning in rail-road terminals

Bruns, Florian 16 September 2014 (has links)
Rail-road terminals are the chain links in intermodal rail-road transportation where standardized load units (containers, swap bodies and trailers) are transfered from trucks to trains and vice versa. We consider three subproblems of the operational planning process at rail-road terminals that terminal operators are facing in their daily operations. These are the optimization problems storage planning, load planning and crane planning. The aim of storage planning is to determine load unit storage positions for a set of load units in a partially filled storage area. Here, different restrictions like non-overlapping of stored load units have to be respected. The objective of storage planning is to minimize the total transportation costs and the number of load units that are not stored at the ground level. For the load planning we assume a scenario of overbooked trains. So, the aim of load planning is to assign a subset of the load units that are booked on a train to feasible positions on the wagons such that the utilization of the train is maximized and the costs for the handling in the terminal are minimized. For the feasible positioning of load units length and weight restrictions for the wagons and the train have to be respected. For the load planning of trains we consider a deterministic version and a robust approach motivated by uncertainty in the input data. The last considered optimization problem is the crane planning. The crane planning determines the transfer of the load units by crane between the different transportation modes. For each crane a working plan is computed which contains a subset of the load units that have to be handled together with individual start times for the transfer operations. For the load units which have to be transfered in the terminal, storage and load planning compute destination positions (inside the terminal). These destination positions are part of the input for the crane planning. The main objective of crane planning is to minimize the total length of the empty crane moves that have to be performed between successive transports of load units by the cranes. We provide MIP-models for all three subproblems of the operational planning process at rail-road terminals. For the storage and crane planning we also propose fast heuristics. Furthermore, we present and compare computational results based on real world data for all subproblems. The main contributions of this thesis concern load and storage planning. For the deterministic load planning we provide the first model that represents all practical constraints including physical weight restrictions. For the load planning we furthermore present robustness approaches for different practical uncertainties. For the storage planning we provide complexity results for different variants. For the practical setting we developed a heuristic which is able to compute solutions of high quality in a small amount of runtime.
230

Work on track! : A train interior design concept to meet contemporary work trends and needs

Abaitua Knight, Alicia M January 2023 (has links)
In a future vision for rail travel, trains will be designed as an activity-based whole space, with different areas for various activities, such as relaxing, socialising or family bonding. My degree project, in collaboration with SJ, proposes a concept carriage dedicated to work, analogous to spending a day at a mobile coworking space. By recognising the new ways of working, this carriage will cater for the needs of different individuals and various types of work and will include private digital meeting spaces, group compartments, collaborative open spaces and cocoon-like seating options in quiet areas. Unlike other modes of transportation, trains allow for passengers to navigate and experience different spaces. By enhancing the use of space and incorporating amenities that improve the user experience, I aim to transform the perception of long train journeys from tedious to exciting and allow a more seamless and efficient way of getting work done while travelling. Ultimately, this degree project encourages sustainable travel through user-centred design.

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