Working at elevated temperature has its challenges due to the high level of complexity whenthe tribosystems operate under harsh conditions, commonly resulting in an increase on thefriction and thermal softening that goes into severe adhesion, severe abrasion and materialtransfer. Despite considerable research, there is a lack of research on tribology applied to hightemperature processes.  The aim of this project is to understand the tribological behavior of tool steel sliding againstaluminum under lubrication conditions working at high temperature. Salt-based, graphite-based, and polymer-based lubricants were evaluated as they are commonly used for aluminum forming. The cleanability of the lubricants after being subjected to elevated temperatures is also studied. High temperature tribological tests were carried out in a reciprocating sliding flat-on-flat configuration for 15 seconds. Optical microscope, SEM and EDS were performed to analyze the specimens after the tribological tests. Then a cleanability study was done to evaluate the cleanability of the lubricants and the effect of temperature on the cleanability of the lubricant. The concentration of the lubricants played an important role in the lubricant’s friction stability and dispersion, particularly for the polymer-based and graphite-based lubricants. Under the tested conditions the salt-based lubricant was ineffective as it showed high and unstable friction. The 10 wt.% polymer-based lubricant concentration presented severe adhesion and material transfer from the aluminum onto the tool steel.  The effect of temperature on the cleanability of the lubricants was correlated to the temperature in which the lubricants start to degrade. Nevertheless, the best cleanability was achieved when using ethanol as a cleaning agent in combination with high pressure spraying, and wirebrush techniques. Mild and high alkaline agents had poor cleanability abilities resulting insurface damage and corrosion on the tool steel.

PALÁN Robert, Production of support forming.A graduation thesis of master´s studies, Mechanical engineering, Department M2307 Metal forging technology, Specialization 02 Forming, Welding, 2. graduate, 2. year, school – year 2007/2008. FSI VUT Brno, ÚST Department of Metal Forging Technology, May 2008, page NO 66, picture NO 36, chart NO 8, suplement NO 12 The graduation thesis, drew up with in the frame of engeneering studies department M2307, submits a concept of a production by forming. A materiál of a forget piece is steel ČSN 12 050, provided as a semi – finished product in a form of a bar 210 mm, lenght 4 000 mm. The particular dimension stocks with be cut from it to forge out a part. Production work is 100 000 pcs. Based on studies of technologies, suitable for producing the part a specific two stage technology of a drop forging was chozen on a vertical forging press LMZ 6 500, with induction heating of the semi – finished product and a product – trim of fin and pellicle or a trimming press LDO 315 A/S. For this alternate all the required calculations are realized of swages and all the necessary machines for the production of are quested enganget part.

The assessment of MQL technology application in reaming process was elaborated in this diploma work. The evaluation of energy intensity was carried out in terms of specific cutting force during reaming of austenitic stainless steel work piece by using HSS reamers. The comparison of economic costs in the case of the application of MQL technology in production was made. Confrontation of oil mist removal principles. At the conclusion the evaluation of ecological benefits for the environment and the positive influence on the working environment cleanness was defined.

This thesis deals with the hydrodynamic plain bearings tractor diesel engine. The first part is closer acquainted with the hydrodynamic bearing, its principles and materials used. The next part work deals with the multibody system adams-engine. The main part of this work is to model the crank mechanism and its storage in hydrodynamic bearings in the MBS program and the subsequent simulation under different operating conditions.

Tato diplomová práce pojednává o návrhu ložisek kompresoru. Za tímto účelem byl zakoupen speciální program JDynamic. Tento software poskytuje cenný přínos při navrhování kluzných ložisek a s tím spojených problémů. Programové výsledky reálného kompresoru jsou obsaženy v parametrické studii. Byl proveden test reálného kompresru. Modifikace kluzných ložisek byly zaměřeny na snížení ztrát.

The thesis deals with complex connecting rod design of two stroke diesel engine with regard to minimising its weight. Three versions of design are suggested and for each of them the stress analyses are implemented and the fatigue safety factors are determined. On the basis of results of implemented analyses and evaluation of all the aspects the most appropriate design is chosen and the production drawing is drawn according to it. In the conclusion, hydrodynamic lubrication plain bearings, which are the integral part of every connecting rod, are designed.

The diploma thesis deals with The study of transition between fully flooded and starved regimes in EHL Contact. The work is focused on problems of starved contact and surface texturing of rubbing surfaces. Surface texturing of rubbing surfaces is one of the adjustments that cause in a sense improved lubricity and reduce friction and wear. The aim of this study is to compare numerical models with real experimental results measured on the Experimental apparatus.

This diploma thesis deals with the experimental study of the influence of operating conditions on the tribological aspects of the wheel flange and rail gauge contact. The wheel flange contact occurs when the vehicle moves on a curve track and it leads to severe up to catastrophic wear regime. For effective reduction of wear is important to apply a suitable amount of lubricant at appropriate intervals into the contact. The issue in this work comprehensively studies using of three laboratory apparatus and six methods that are theoretically and experimentally compared. Assessed are friction, wear, distribution and film thickness of lubricants for different contact conditions. The resulted amount of lubricant and interval of its application eliminates development of seizure at low consumption of lubricant. The understanding of mechanisms that occur in the wheel-rail contact not only helps to reduce operating costs and improved to energy efficiency of movement of vehicle on a track, but it is the basis for safe, reliable and ecological operation of rail transport.

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.

This diploma thesis deals with the proposal of methodology for film thickness eva- luation within compliant contacts. With respect to characteristics of such contact pairs, like variable film thickness, high surface roughness, or poor conductivity and reflectivity, the usage of conventional experimental methods is particularly complicated. In present study, an optical method based on the principle of fluo- rescent microscopy was employed in present thesis. An evaluation algorithm in- volving background normalization and calibration of fluorescent intensity to film thickness was created in a form of experimental software. The proposed algori- thm was validated by using elastohydrodynamic contact formed between ceramic ball and glass disc. The measured film thickness was compared with theoretical prediction, while very good agreement of obtained data was observed. Further, a series of experiments with compliant samples was conducted, while the central film thickness was evaluated as a function of mean speed, applied lubricant, ap- plied load and slide-to-roll ratio. The last part of the thesis is focused on results analysis and discussion considering the previously published literature.