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Influence of friction modifiers composition on traction in wheel-rail contact
Kvarda, Daniel ; Hartl, Martin (referee) ; Galas, Radovan (advisor)
Friction modifiers are a new effective way to control adhesion in wheel and rail contact. The aim of this diploma thesis is experimental study of the influence of the constituents of water based friction modifier on adhesion. Measurement of the adhesion behavior for different friction modifier compositions is carried out on a ball–on–disc laboratory device creating point contact. The introductory part of the experiments describes the effect of individual components on adhesion. Subsequently, combinations of different friction modifier compositions are tested. In conclusion, selected compositions are used for wear tests. The results obtained show that the performance of friction modifiers is greatly influenced by evaporation of base medium.
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Off-board systems for top-of-rail lubrication
Málek, Jan ; Kvarda, Daniel (referee) ; Galas, Radovan (advisor)
This bachelor’s thesis is focused on rail off-board lubrication system. The main part of this thesis is explaining of function and design few certain lubrication systems. In this thesis are explained aspects of wheel-rail contact, such as types and parts of rail, adhesion, slip, creep–traction diagram. Another part of this thesis is description of few certain lubrication system for top of rail and gauge face application. In this thesis are explained product of major companies of friction management industries such as SKF-Lincoln, Whitmore, Loram. Additional part of this thesis speaks about usage and development of this devices in Czech Republic. Output of this thesis is conclusion about advantages and disadvantages these certain devices.
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Materials for friction modification within wheel-rail contact
Pláněk, Miloslav ; Kvarda, Daniel (referee) ; Galas, Radovan (advisor)
Problematic aspects of wheel-rail contact can be reduced by application of substances for friction modification. The essence of this bachelor’s thesis is compile overview of substances for friction modification applied on Top of Rail with focus on that one, which are applied to decrease excessive wear and noise. In this thesis, the reader will be firstly introduced to the fundamentals of wheel-rail contact, essence of friction management and partition of substances for friction modification. Next part of the thesis is focused only on substances providing intermediate level of friction. These substances are TOR friction modifiers, TOR lubricants and TOR solid compositions. Thesis describes their composition, ways of application, expected benefits and map commercial products available on the market. The output of the bachelor’s thesis is overview of these substances and their comparison based on theoretical assumptions, test´s results and practice experience. The thesis will allow reader to have better market orientation between available products, which could be wrong tagged by their own producers.
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Animation of cylindrical gears meshing
Kvarda, Daniel ; Klapka, Milan (referee) ; Hartl, Martin (advisor)
This thesis deals with meshing relations, geometric, kinematic and force effects occuring during meshing of cylindrical gears with straight and helical teeth. This problematic is clarified with created animations, that are explained and described in this thesis. Animations serve for educational purposes.
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Rolling bearing stiffness
Krišpín, Jakub ; Kvarda, Daniel (referee) ; Košťál, David (advisor)
Given bachelor thesis deals with stiffness of model shaft configuration which is mounted overhung in two single row radial ball bearings. Initial part of the thesis is focused on roller bearings and parameters affecting their stiffness. Then a model assembly is designed. The stiffness calculation calculation of the assembly is performed by MESYS software. Subsequently, an experimental stiffness measurement is performed. Stiffness is determined by measuring the deformation of the shaft at given load. Values are compared with each other and the sensitive points in the calculation are determined. The results of the thesis mainly lead to determination of the magnitude of the influence of individual parameters on the change in stiffness. The functionality of the MESYS software was verified.
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Parametric computational model of non-food bulk materials silo
Červený, Vojtěch ; Kvarda, Daniel (referee) ; Maňas, Pavel (advisor)
This bachelor thesis deals with the creation of a parametric computational model of a bulk material silo. The work includes acquaintance with the issue of bulk materials, the theory of calculation of pressure conditions in silo, introduction of the proposed structure, creation of a parametric geometric model in the CAD system and the calculation model in the FEM system. The thesis includes a brief introduction to the software used and the principle of working with the created models.
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Experimental investigation and numerical modelling of top of rail products
Kvarda, Daniel ; prof.Roger Lewis (referee) ; Meierhofer, Alexander (referee) ; Hartl, Martin (advisor)
Tato disertační práce se zabývá experimentálním a numerickým studiem maziv pro temeno kolejnice. Tyto maziva se používají ke snížení opotřebení, hluku a zlepšení energetické účinnosti kontaktu kola a kolejnice. V posledních dvou desetiletích byl proveden rozsáhlý experimentální výzkum týkající se použití maziv pro temeno kolejnice. Avšak velmi málo výzkumu bylo zaměřeno na základní mechanismy těchto produktů, zejména na problémy s nízkou adhezí. Aplikace matematických modelů v této oblasti také nebyla dosud zkoumána. Cílem této práce je pomocí matematického modelu vysvětlit třecí chování a problémy s nízkou adhezí maziv pro temeno kolejnice. Model předpokládá jak tření vznikající interakcí nerovností pevných látek, tak separaci mazacím filmem. Validace tohoto modelu byla provedena na experimentálním tribometru se schopností měřit tloušťku filmu pro ověření přesné predikce separace povrchu. Komerční tribometr byl použit ke zkoumání vlivu jednotlivých složek v mazivu pro temeno kolejnice na bázi oleje. Sada reologických testů v kombinaci s modelem ukázala, že pevné částice měly velmi malý vliv na zvýšení adheze po aplikaci. Následně byly testovány různé typy maziv pro temeno kolejnice pomocí vysokotlakého torzního zařízení. Mezný režim tření těchto látek byl hodnocen představeným modelem. Bylo zjištěno, že pozitivní třecí vlastnosti, které by tyto produkty měly poskytovat, jsou výsledkem velké skluzové vzdálenosti, která mění složení třecí vrstvy. Nízký koeficient tření v důsledku nadměrné aplikace se vyskytl při stejném aplikovaném množství u všech testovaných látek. Tato diplomová práce představuje původní výzkum rozšiřující znalosti o produktech pro temeno kolejnice.
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Design of device for material antiseizure testing
Burk, Filip ; Kvarda, Daniel (referee) ; Šperka, Petr (advisor)
Friction between materials can be partially eliminated by lubrication between surfaces. In order to select the correct lubricating oil, it is necessary to have the necessary test means to make an evaluation. One of these is a four-ball tester, which is lacking at the BUT Institute of Design. The aim of the bachelor thesis is the design of a modification of the existing tribometer R-MAT 3 for a four-ball configuration. The review part includes a description of the preparation, measurement and evaluation of the four-ball tester and an evaluation of conventional testers. The design of the ball mounting, drive and torque transfer to the tribometer spindle was carried out. Measurement and recording of friction torque, contact force and temperature during the test was also proposed. The result is a configuration ready for implementation. The review section includes a description of the preparation, measurement and evaluation of the four-ball test and an evaluation of conventional testers.
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The modification of a field tribometer frame
Matějček, Ondřej ; Kvarda, Daniel (referee) ; Valena, Martin (advisor)
The main topic of this Bachelor thesis is a modification of a field tribometer frame. Firstly, the research of field tribometers measuring coefficient of adhesion on the real track was conducted. Next, the current state of the tribometer to be modified was analysed. Based on research and tribometer current state analysis the parameters of the design were determined. Followed by several conceptual variations of the frame and attachment mechanism. From these solutions, the best one was selected and processed into the final form. The results of this thesis are field tribometer frame with attachment mechanism. The Bachelor thesis also contains drawing documentation.
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Rolling bearing stiffness
Krišpín, Jakub ; Kvarda, Daniel (referee) ; Košťál, David (advisor)
Given bachelor thesis deals with stiffness of model shaft configuration which is mounted overhung in two single row radial ball bearings. Initial part of the thesis is focused on roller bearings and parameters affecting their stiffness. Then a model assembly is designed. The stiffness calculation calculation of the assembly is performed by MESYS software. Subsequently, an experimental stiffness measurement is performed. Stiffness is determined by measuring the deformation of the shaft at given load. Values are compared with each other and the sensitive points in the calculation are determined. The results of the thesis mainly lead to determination of the magnitude of the influence of individual parameters on the change in stiffness. The functionality of the MESYS software was verified.
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