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Friction of compliant contacts
Vala, Martin ; Galas, Radovan (referee) ; Nečas, David (advisor)
This bachelor’s thesis deals with the study of the friction of compliant contacts and parameters affecting it. First section of this thesis provides analysis of current problematics with friction and compliant materials. In the next section basic definition of friction, compliant material and compliant contacts is provided with an actual study of up-to-date articles. Last section of this thesis is discussion dealing with all the articles and pointing out the influencing parameters. Followed by potential research pathways.
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Friction coefficient analysis of the turbocharger bypass valve
Wolf, Juraj ; Spáčil, Tomáš (referee) ; Krejčí, Petr (advisor)
Aim of the diploma thesis is set to present a new method for evaluation of the friction coefficient of the wastegate valve system. A test fixture was designed and manufactured for this purpose. Simulations in ANSYS and MSC Adams support test results. The developed method provides an accurate and affordable solution for investigating of friction coefficient for various valves of turbochargers wastegate.
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Complete characterization of the ceramic-based hot-coated coating on the AZ91 magnesium alloy
Plevová, Kateřina ; Doskočil, Leoš (referee) ; Wasserbauer, Jaromír (advisor)
The diploma thesis is focused on the study of the thermal sprayed coating consisting of the NiCrAlY alloy bond layer and the partially stabilized zirconium oxide (8YSZ) top layer on the AZ91 magnesium alloy. The theoretical part deals with the structure of the alloy AZ91, NiCrAlY and partially stabilized zirconia. Furthermore, the methods of thermal spraying and the function and properties of thermal barrier coatings are summarized. The experimental part deals with the characterization of the thermal sprayed coating and the AZ91 alloy in terms of elemental, structural and phase composition. Optical and electron microscopy, EDS and XRD analysis were used for characterization. Electrochemical properties were investigated in~3.5% sodium chloride solution by potentiodynamic polarization. The mechanical properties (hardness, coefficient of friction) of the substrate and coating were measured using a hardness tester and tribological tests.
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Dynamic vehicle-road interaction
Svršek, David ; Blaťák, Ondřej (referee) ; Fojtášek, Jan (advisor)
Bachelor’s thesis, Dynamic vehicle-road interaction, deals with a summary of basic knowledge about the acting force and factors that affect interaction of vehicle with surface. The work is divided into six parts, which deals with the definition of basic concepts and characteristics of dynamics, traction vehicle, braking, maneuverability, the chassis aspects influencing the traction and anti-skid road surface properties.
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Boundary Conditions in the Roll Gap during Hot and Cold Rolling
Luks, Tomáš ; Pernis,, Rudolf (referee) ; Hajduk, Daniel (referee) ; Horský, Jaroslav (advisor)
Boundary conditions in the roll gap play an important role in modelling of rolling processes. In the roll gap we can observe the following: changes of rolling pressure, changes of relative velocity, influences of oxides and lubrication, etc. When taking into account all conditions mentioned above the determination of the boundary conditions is not trivial and extensive measurements are necessary. Therefore, this thesis is dealing with design of temperature and force sensors specified for the determination of friction coefficient and heat transfer coefficient in contact. The temperature sensor with an installed thermocouple measures subsurface temperature for a given depth; and then the inverse heat conduction task is used to compute temperature and heat flux on the surface. Several temperature sensors were designed and used for measuring in pilot mill and industrial rolling mill as well. The thermal responses of different sensors were compared in the numerical simulations. The inverse calculations were tested for various rolling conditions. A durability of the sensors was also studied in industrial rolling conditions. The contact stresses in the roll gap were measured by a pin, which was in direct contact with the rolled material. The forces on the top of the pin were measured by a three-axes piezoelectric force transducer and recalculated to the contact stress and friction coefficient. The sensor was implemented in a work roll and tested when rolling aluminium and steel slab for different rolling conditions. The results were compared with the integrative force sensor ROLLSURF.
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Dynamic vehicle-road interaction
Svršek, David ; Blaťák, Ondřej (referee) ; Fojtášek, Jan (advisor)
Bachelor’s thesis, Dynamic vehicle-road interaction, deals with a summary of basic knowledge about the acting force and factors that affect interaction of vehicle with surface. The work is divided into six parts, which deals with the definition of basic concepts and characteristics of dynamics, traction vehicle, braking, maneuverability, the chassis aspects influencing the traction and anti-skid road surface properties.
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Worm conveyor
Pelka, Tomáš ; Škopán, Miroslav (referee) ; Malášek, Jiří (advisor)
This bachelor project deals with, specifies and makes design of the worm horizontal conveyor. The project is divided into drawings and written part including the funcional capacity calculation and electromotor output. Further the part includes proposal of key dimensions of the conveyer with the soilidity control of the worm, solving of the suspended bearings, assemble issues, maintenance and potencial exchange of the worm due to abrasion.
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