This work analyzes problems of friction and lubrication of total hip replacement (THR). At first, experimental study of friction coefficient under various conditions was conducted using hip joint simulator based on principle of pendulum. After that, lubrication film development was observed, using colorimetric interferometry with head from THR and glass cup with respect of geometry and clearance to cups made originally for THR. With respect to research study [25] it was found that increasing contact conformity leads to increased film thickness. Also protein adsorption on articulating surfaces was observed. Thanks to adsorption 80 nm film thickness was measured even if relative surface speed was zero. Furthermore protein aggregation was observed on the border of contact zone, similar aggregations were observed by Myant et al. [29] or Vrbka et al. [25]. These aggregations are formed when lubricant is under shear stress and it can positively affect film thickness. If the relative motion of articulating surfaces is not sufficient, the protein layer can`t be refreshed enough and film thickness start decreasing. Coefficient of friction 0,13 was measured when lubricating film development was observed. Close to this value are material combinations metal on polyethylene and metal on metal.

V rámci této práce byl vyvinut komplexní simulační nástroj, vycházející z výpočtového modelování fyzikálních a chemických dějů, který je doplněn vhodnými matematickými postupy. Výsledný software je schopen stanovit ztrátový výkon sady pístních kroužků pomocí účinků klíčových mechanismů a jejich vzájemné interakce při standardním provozu pístních kroužků. Simulační výstupy byly navrženy v souladu se zájmy průmyslové praxe, např. určení objemového toku plynů pístní skupinou, ztrátové výkony vlivem tření a spotřeba oleje, která je ovlivněna sadou pístních kroužků. Při vývoji simulačního modelu byly technické experimenty vykonány na tříválcovém zážehovém motoru za účelem získání vstupních dat a ověření výsledků. Možnosti navrženého simulačního nástroje jsou na tomto motoru dále demonstrovány v podobě parametrických studií, využitelných zejména při návrhovém procesu. Cílem dizertační práce bylo zaplnit mezeru ve výzkumné oblasti simulačních nástrojů, které mohou účinně propojit výpočtové modelování třecích ztrát a současně i spotřeby oleje, a podpořit tak výrobce pístních kroužků a vývojová oddělení spalovacích motorů.

This dissertation is focused on the effects of both artificially produced and real roughness features on mixed lubrication film formation during start-up and reversal of non-conformal contacts operated under rolling/sliding conditions. The start-up operation of mixed lubricated contacts represents one of the transient conditions that bring the risk of the surface damage because of asperities interactions. Chromatic interferograms captured by CMOS high-speed camera during start up of the motion enabled to observe the detailed changes in lubrication film caused by surface features. The observation of the effects of surface dents artificially produced on the ball surface helped to understand better the behaviour of real surface topography. It was found that the presence of shallow surface features can help to separate mixed lubricated rubbing surfaces more efficiently than it could be suggested from the results obtained with smooth surfaces. It can be suggested from the obtain results that properly designed topography of the rubbing surfaces can help to reduce the asperities interactions under transient operational conditions.

This dissertation thesis deals with elastohydrodynamic lubrication (EHL) of surfaces with real roughness. Systematic study of surface harmonic components behaviour, during their passage of the EHL contact, by other authors led to retrieval of a uniform principle according which individual harmonic components deform inside the contact. Although the amplitude attenuation model can provide rapid tool for more accurate surface assessment in design process it has not been validated on real surfaces till now. The thesis represents pioneering work on quantitative analysis of real surfaces EHD measurements. It contains original and new results with real and model roughness features that in many cases confirm theoretical expectations. Deeper understanding of surface roughness behaviour inside EHL contact, which is typical for machine parts like bearings, gears, cams etc., can help to improve design process of the components and ultimately enable machines and equipment to work with lower energy requirements and higher durability.

This PhD thesis deals with elastohydrodynamic lubrication (EHL) under the conditions that occur between mated hypoid gear teeth. The aim is to describe experimentally the behaviour of lubricating film and mechanisms of its formation. The focus is mainly placed on clarifying the influence of direction and magnitude of sliding velocity in circular and elliptical contacts. Generally, it is still assumed that the direction of sliding velocity has no effect on the resulting lubricant film. In this study optical interferometry is used to determine distribution of lubricant film thickness. This work includes new and original results which clarify the studied problem. It was found that the direction of sliding velocity affects shape of the film at high speeds. This relates to the effect on heat flow through the contact. The results have an impact on the development of general EHL theory and provide knowledge applicable in film thickness prediction in the design of real tribological nodes.

The work deals with the process of lubrication of gears from a combination of materials that have significantly different material properties. The experimental measurement is performed on a tribometer in simulated gear contact with a ball-disk configuration. The Chromatic Optical Interferometry method is used to measure the formation of a lubricating film in contact. The purpose of this work is to clarify the process of film thickness formation and compare experimental measurements with predictions, which are valid in Soft EHL regime.

This thesis describes the methods and procedures used in designing production lines, focusing on the production line for machining of train wheels. The thesis also describes the basic types of railway wheels, their design and important design elements. It also deals with the complete manufacturing process of train wheel from material selection through the technological processes of forming, heat treatment, mechanical tests, machining and non-destructive testing and measuring. Suitable equipment for the construction of automatic lines for machining, inspection and measurement of train wheels is selected according to the specified parameters of the wheel types, manufacturing productivity and production shop dimensions, These devices include vertical machining center, single-purpose machine for grease outlet drilling, device for ultrasonic inspection, magnetic particle inspecton device, measuring station and train wheel balancing machine. Several variants of the production line including detailed specification of manipulation cycle times is created. These variants are mutually compared and evaluated to find the optimal solution.