Academic literature on the topic 'Mazací vrstva'

Od Aristotela promatrana kao jezična figura, ukras stanovite vrste strogo ograničen na područje poetike i retorike, metafora proživljava svojevrsnu renesansu unutar područja kognitivne lingvistike i teorije konceptualne metafore. Pokazalo se kako metafora nije ukras nego upravo nešto fundamentalno bez čega jezik i mišljenje zapravo ne mogu. Metaforički jezični izrazi tek su površinski odrazi, odnosno manifestacije konceptualnih metafora u našem umu. Sustav konceptualnih metafora strukturira naš svakodnevni konceptualni sustav na temelju kojega se odvija razumijevanje. Koncepti koji upravljaju procesima mišljenja nisu samo stvar intelekta, nego utječu na naše svakodnevno funkcioniranje do najsitnijih pojedinosti. Koncepti strukturiraju što percipiramo, kako se snalazimo u svijetu u kojemu živimo, kako se odnosimo prema drugim ljudima i slično, pa su stoga način na koji mislimo, ono što doživljavamo i ono što svakodnevno činimo u mnogočemu pitanje metafore. Na primjeru leksema jasan i frazema (za)mazati oči ukazali smo na konceptualnu vezu znanja i gledanja, odnosno na konceptualnu metaforu ZNATI JE VIDJETI, koja rasvjetljava nerazdvojnu povezanost znanja s gledanjem i (djelomično) način mišljenja i djelovanja modernoga čovjeka, čime smo utvrdili da je metafora jedan od temelja funkcioniranja jezika te da je mišljenje duboko prožeto metaforičkom strukturom.

ectroscopic reflectometry is measurement technique that enables the study of the thickness and refractive index of thin layers. This thesis deals with its use for the study of lubrication films within EHD contact and verifies a new approach suggested in recent publications. It is focused on the development of an optical arrangement and mathematical model for the lubrication film thickness measurement within the entire EHD contact. This technique brings the possibility to study the pressure distribution within the contact area through the evaluation of changes in lubricant refractive index.

This diploma thesis is concerned with simulation of elastohydrodynamic lubrication of point contacts using the finite element method. The first part of the thesis focuses on the study of the issue and introduces equations for model creation and numerical methods which can be used for EHD calculation. The most suitable solution approach has been chosen from the overview, namely the Full system approach. The software we chose for applying the method was COMSOL Multyphysics. The following part of the thesis deals with model’s creation and gives its elaborate description. We introduce models for calculation of line and point EHD lubrication for newtonian lubricants and, last but not least, we also present a model for calculation of point contact EHD lubrication for non-newtonian lubricants. The next part of the thesis then verifies all the models. That is achieved by comparing the calculated results to results from different papers. The conclusive part of the thesis then examines the matches of acquired results to different prediction relationships and experiments.

This diploma thesis deals with an application of the finite element method on elastohydrodynamic (EHD) lubrication simulations. Commercially available software COMSOL is used for the computation, while two different modules for modeling EHD lubrication are described in a detail. Firstly, a new approach using the module Thin-Film Flow is developed, considering and describing some limitations of this approach. This is the very first published work dealing complex with EHD simulation in Thin-Film Flow module. In the second part of the thesis, there was created a model of line contact using the module for the introduction of partial differential equations (PDE). The model is partially verified with available works for different values of the input parameters. Subsequently, the velocity effect of the contact surfaces on the pressure and the lubricant thickness in contact is analyzed. Finally, the last part is examines the influence of the values of some parameters on the final value of the contact pressure and the lubricant thickness, as well as on numerical stability of the entire model.

The work investigates the reduction of friction between non-conformal macro contacts with partial slip. The measurement of the coefficient of friction, with the magnitude of the superlubricity, is extended by the influence of relative slip, direct observation of the contact area and the measurement of the thickness of the lubricating film. It also includes a comparison of changes in topography by friction. The experiments were mainly performed on a ball-on-disk tribometer with measuring the film thickness by colorimetic interferometry. The surface roughness changes were investigated using an optical profilometer. The effect of mean velocity, slide-to-roll radio and topography were observed for selected combinations, one of which did not allow the measurement of film thickness and one did not achieve the expected reduction in friction. For the other combinations, it was possible to observe a reduction of the coefficient of friction to 0,003 or less. The influences affecting the friction between selected materials have been investigated considerably. Thus, a foundation is laid for the research of superlubricity between contacts with partial rolling. The thesis could contribute to the reduction of friction losses, earlier(quicker/faster?) and more common use of some lubricants and materials in mechanical engineering.

This master’s thesis focuses on hydrodynamic plain bearing drivetrain in-line sixcylinder diesel tractor engine. In the first part is used as reported in contemporary bearing materials and design solutions bearing basins. Furthermore, given the general Reynolds equation of hydrodynamic lubrication. The main part of the thesis is devoted to creating a virtual model of the crank mechanism in MBS system ADAMS/Engine. Rigid crankshaft in this model is replaced by the flexible crankshaft, which is prepared in the FEM software ANSYS and then exported. The final section presents the results of simulations and their evaluation.