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Optimization Of Selected Proposed ČSN Elements For Road Design
Kokeš, Ondřej ; Čepil, Jiří (referee) ; Radimský, Michal (advisor)
Diploma thesis describes and researches some proposed ČSN 73 6101 elements for road design and their subsequent comparison with Norma de Traçado that is main law for road design in Portugal. In practical part, the speed of vehicles during moving on direction curves is researched and subsequently coherence of theoretical assumptions with real speeds is compared. The main aim of this work is to verify the assumption that design speed does not correspond to the real speed that drivers move on road structures.
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Pavement skid resistance and Skid Resistance Index
Nekulová, Pavla ; Šachlová, Zora (referee) ; Kudrna, Jan (advisor)
This diploma thesis deals with the relation between the longitudinal friction coefficient dependence on measuring speed and the value of road surface macrotexture MPD. Results of longitudinal friction coefficient and value of MPD measurement on 73 sections are included in this thesis. The results were compared by regression analysis and its outcome was used for determination of formula that enable calculation of longitudinal friction coefficient for any operating speed when longitudinal friction coefficient for 60 km/h and value of macrotexture are known. The evaluation scale for skid resistance index (SRI) was also determined in this thesis. It could be used for evaluation of skid resistance independently of the type of device used for friction coefficient measurement.
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Dependance of pavement surface skid resistance on aggregate polishing and traffic loading
Dašková, Jaroslava ; Čelko,, Ján (referee) ; Šachl,, Jindřich (referee) ; Vojtěšek, Antonín (referee) ; Kudrna, Jan (advisor)
Road safety is a complex problem. It is influenced mainly by the driver, the vehicle and the road surface. This thesis is focused on the road surface properties and especially skid resistance that directly affect the braking distance and keeping the vehicle in the horizontal curves and thus traffic accidents. The thesis deals with the durability of pavement surface skid resistance, the type of pavement layers and aggregate polishing used in wearing course. The aim of this thesis was to develop the methodology for improvement of road surfaces skid resistance durability and implementation of functional test for their assessment.
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Comparison of frictional properties of cosmetic massage products
Dohnal, Petr ; Čípek, Pavel (referee) ; Vrbka, Martin (advisor)
This bachelor’s thesis examines tribological properties of massage products (creams and oils). Its aim is to create a comparison of the selected products. Tribometer in the pin-on-plate configuration was used for the experiment because of its ability to simulate the process of rubbing the product on the skin. Cowhide was used as a model of human skin. The attributes of products were compared based on the characteristics of the coefficient of friction during the measurements. Through the experiments a suitable parameter was found for easy comparison of the product's durability. According to the results the best oil was selected in terms of durability and lubrication. The thesis could be used as a basis for creating a standardised method for evaluation and selection of products suitable for massage purposes.
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Friction of materials for optomechanical parts
Mořický, Ondřej ; Košťál, David (referee) ; Šperka, Petr (advisor)
This bachelor thesis deals with friction between materials used in the construction of optomechanical assemblies. The aim of the thesis is to compare coefficient of friction for different combinations of surfaces, different roughness, and different surface treatments. Experimental measurement was carried out on a tribometer using the pin-on-plate method under the dry friction conditions. Graphs of the development of coefficient of friction over time and a table to compare individual combinations were compiled from the results of the measurement. It includes an analysis of surfaces using optical profilometry before and after the tests.
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The effect of surface condition of artificial joint cup on the friction coefficient
Černohlávek, Mikuláš ; Dočkal, Kryštof (referee) ; Nečas, David (advisor)
This bachelor’s thesis deals with the effect of microtextured surface of an artificial joint cup on a friction coefficient. The primary aim of this thesis was to compare friction coefficients of original and microtextured joint cups. Experimental measurements were made on pendulum hip joint simulator and results were evaluated in Matlab. Four types of femoral heads (CoCrMo, BIOLOX Delta, BIOLOX Forte and oxinium) and three types of lubricants (PBS, model synovial fluid and hyaluronic acid solution) were used during the measurements. The results show, that using PBS and synovial fluid leads to decrease of the coefficient of friction while using modified joint cup. We can assume that microtextured surface of artificial joint cup (separately or in combination with microtextured femoral head) could be a significant benefit for prolonging lifespan of implants.
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Design and execution of additional module of laboratory equipment for measurement of friction within lubricated contacts
Stifter, Jan ; Šperka, Petr (referee) ; Frýza, Josef (advisor)
This bachelor‘s thesis presents the design and implementation of a module of laboratory device for measuring coefficient of friction and friction forces in elastohydrodynamic lubricated contacts. The module is able to measure friction forces in two perpendicular axes. A motivation for realization of this module was the absence of a similar equipment. The retrieval section of this thesis is dedicated to tribology, strain gauges (force sensors) and compliant mechanisms. The selection of the appropriate concept of the module and the force transducers is solved in the design part of thesis. The compliant mechanism with flexure hinges was designed via FEM analysis. This mechanism allows the displacement of the contact member of module in the direction of the frictional forces acting within a lubricated contact. The proposed module was manufactured, implemented in laboratory equipment and its functionality was tested. According to preliminary results, the module fulfilled the objectives of this thesis.
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Design of a simulator module for analysis of friction and wear of teeth during cleaning
Snopek, Lukáš ; Streďanská, Alexandra (referee) ; Vrbka, Martin (advisor)
This thesis focuses on the design of a module for the tribological simulator Bruker UMT TriboLab, which will be used in research in the field of analysis of wear of hard dental tissues and filling materials due to tooth cleaning. The aim of this work was the design of experimental conditions, module construction, creation of drawing documentation, production and subsequent implementation of a validation experiment. The conditions of the experiment were determined on the basis of research and to create an optimal design solution, prototypes were continuously produced using the 3D printing method. Finally, two toothbrush fixtures and two dental filling sample fixtures were made based on the drawing documentation. Subsequent assembly of the fixtures and the implementation of the experiment on the tribometer verified their functionality, which makes it possible to declare all the goals successfully met. Now these fixtures will be part of several research tasks in the field of oral biotribology.
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