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Testing of Rail Lubricants Performance
Tomčová, Renata ; Polach, Pavel (referee) ; Galas, Radovan (advisor)
Top-of- rail lubricants are an effective way to control adhesion, reduce contact wear and noise in rail transport. However, despite the widespread use of these lubricants, there is currently no standard defining how to test and evaluate their performance. This work aims to develop a methodology for testing top-of-rail lubricants in a laboratory environment using a tribometer in a ball-on-disk configuration. At first, important operational parameters of experiments are analyzed and experimentally tested. These are mainly wear-in and run-in, method of application, roughness and geometric parameters of contact bodies. The result of this work is a testing methodology that guarantees good repeatability and reliability of results. In the last part of this work, the methodology is verified using commercial top-of-rail lubricants.
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The effect of surface roughness on friction and lubrication in simulated gear contact
Mořický, Ondřej ; Čermák, Jan (referee) ; Šperka, Petr (advisor)
This diploma thesis deals with experimental study of the effect of surface roughness on lubricating film formation and friction behaviour in lubricated point contact. The ball-on-disc contact is operated under conditions of transition from mixed to elastohydrodynamic lubrication regime. The measurement of the thickness of thin lubrication films on generally rough surfaces is approached by fluorescence microscopy. The effects of magnitude and character of the initial roughness, including their evolution during the running-in processes, are described. The result is a closer understanding of the mechanisms taking place in this type of contact and the identification of the optimum surface roughness in terms of resistance to changes during running-in for specific operating conditions.
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Running-in of machine elements
Rejent, Pavel ; Křupka, Jiří (referee) ; Šperka, Petr (advisor)
This bachelor’s thesis deals with the effect of topography change on the running-in of a machine element. The objective was to evaluate the time change of the friction coefficient during running-in of five steel balls with different surface treatment. The experiment was performed in mixed lubrication regime. There was also a task to measure the change of surface topography after a concrete time intervals. Another task was to evaluate a fluid film thickness for every steel ball. The output of the measurement are graphs containing the time function of friction coefficient and time change of selected surface topography parameters. The change of topography was also displayed on Abbott-Firestone curves and the fluid film evaluation was compared with the predicted value. The thesis improves knowledge about running-in process and provides comparison for surface machining by three different types of sandpaper and shown change in the behaviour of machine element after lapping or polishing.
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The effect of surface roughness on friction and lubrication in simulated gear contact
Mořický, Ondřej ; Čermák, Jan (referee) ; Šperka, Petr (advisor)
This diploma thesis deals with experimental study of the effect of surface roughness on lubricating film formation and friction behaviour in lubricated point contact. The ball-on-disc contact is operated under conditions of transition from mixed to elastohydrodynamic lubrication regime. The measurement of the thickness of thin lubrication films on generally rough surfaces is approached by fluorescence microscopy. The effects of magnitude and character of the initial roughness, including their evolution during the running-in processes, are described. The result is a closer understanding of the mechanisms taking place in this type of contact and the identification of the optimum surface roughness in terms of resistance to changes during running-in for specific operating conditions.
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Testing of Rail Lubricants Performance
Tomčová, Renata ; Polach, Pavel (referee) ; Galas, Radovan (advisor)
Top-of- rail lubricants are an effective way to control adhesion, reduce contact wear and noise in rail transport. However, despite the widespread use of these lubricants, there is currently no standard defining how to test and evaluate their performance. This work aims to develop a methodology for testing top-of-rail lubricants in a laboratory environment using a tribometer in a ball-on-disk configuration. At first, important operational parameters of experiments are analyzed and experimentally tested. These are mainly wear-in and run-in, method of application, roughness and geometric parameters of contact bodies. The result of this work is a testing methodology that guarantees good repeatability and reliability of results. In the last part of this work, the methodology is verified using commercial top-of-rail lubricants.
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|
|
Running-in of machine elements
Rejent, Pavel ; Křupka, Jiří (referee) ; Šperka, Petr (advisor)
This bachelor’s thesis deals with the effect of topography change on the running-in of a machine element. The objective was to evaluate the time change of the friction coefficient during running-in of five steel balls with different surface treatment. The experiment was performed in mixed lubrication regime. There was also a task to measure the change of surface topography after a concrete time intervals. Another task was to evaluate a fluid film thickness for every steel ball. The output of the measurement are graphs containing the time function of friction coefficient and time change of selected surface topography parameters. The change of topography was also displayed on Abbott-Firestone curves and the fluid film evaluation was compared with the predicted value. The thesis improves knowledge about running-in process and provides comparison for surface machining by three different types of sandpaper and shown change in the behaviour of machine element after lapping or polishing.
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