The plasticity index has often been invoked as an indicator of the most likely condition for scuffing of metals. The particular condition for initiating scuffing was thought to be 2% plastic strain in contacting asperities, which would lead to adhesion between asperities. E~eriments were done to validate the hypothesis using low alloy steels and stainless steel, lubricated with plain mineral oi...

The paper presents some typical results regarding the evolution of friction torque during four balls scuffing tests. tests were conducted in 10 seconds running periods having 100 N loading steps, according to ISO 20623:2017. For testing, 12.7 mm bearing manufactured by SKF used and as lubricant, U90Ca3 grease was used. A special device conceived built evaluate between using a force transducer m...

Metal matrix composites are undoubtedly a group of advanced engineering materials. Compared to unreinforced matrix material, they are characterized by increased strength, greater stiffness, increased wear resistance, better mechanical properties and dimensional stability at elevated temperatures as well as lower density. Due to its very favorable tribological properties for many years research ...

Abstract General reductions in lubricant viscosities many machine components mean that the role of additives forming tribofilms has become increasingly important to provide adequate surface protection against scuffing. However, relationship between scuffing and formation removal not been systematically demonstrated. In this study, a step-sliding speed test based on contra-rotation using MTM-SLI...

The diversity of multidisciplinary approaches suggests that fundamentals of scuffing require systemic, complex multi-scale and multi-physics analysis of an irreversible process as it is postulated in present study. That is probably one of the reasons of lack of unequivocal model of this irreversible transitional process from stable more or less lubricated wear to scuffing described only by one ...

The slow progress in the understanding of scuffing (scoring) and runningin of most lubricated surfaces is probably due to an inadequate understanding of the details of asperity deformation and oxide formation. The thickness and properties of oxides influence the stress states imposed on asperities as much as does the liquid lubricant, but the oxides are ignored in theories. Present theories als...

Free-piston diesel engines are characterized by freely moving pistons without any crankshaft or camshaft connected to the pistons. This allows a compact and efficient engine design, but requires automatic control of the piston motion. This paper present a dynamic mathematical model of a free-piston diesel engine, and a control oriented dynamic analysis leading to a piston motion control structu...

Diagnostic methods including bearing problems represent one of the most important challenges. The scuffing phenomenon initiation of the bearing elements produces an important increase in the vibration level and can be emphasized by the analysis of the bearing friction forces which are the most sensitive indicator of the bearing failure. Commonly used technique for damage detection is the vibrat...

The relationship between a Lubrication Mode Diagram (LMD) for concentrated contacts (LCC‘s) and the ‘IRG transition’ diaLubrication Modes and the IRG Transition D i ag ram gram has been studied. In addition, scuffing results, obtained by the IRG (International Research Group) have been analysed, as well as the results of scuffing tests performed by different workers using a two-disc apparatus. ...