scholarly journals SLIDING BEARING DIAGNOSTICS

2017 ◽  
Author(s):  
A.A. Novikov ◽  
S.V. Korotkevich ◽  
N.F. Solovey
Keyword(s):  
Contact Resistance ◽  
Operating Regime ◽  
Boundary Friction ◽  
Lubricant Layer ◽  
Control Analysis ◽  
Threshold Values ◽  
Sliding Bearing ◽  
Electrical Circuits ◽  
Bearing Diagnostics ◽  
Boundary Lubricant

An explanation of electrophysical sounding method using for sliding bearing diagnostics at a boundary friction is given. Electrical circuits and a sliding bearing diagnostic way, where the control analysis of a boundary lubricant layer (BLL) thickness is realized indirectly in accordance with contact resistance parameters are developed. The sliding bearing greasing state is defined according to installed threshold values in advance which achievement defines it operating regime.

Contributions to the Influence of Retained Austenite Content in Steels on the Temperature Stability of Boundary Lubricant Layers in Friction

1975 ◽  
Vol 97 (3) ◽  
pp. 512-515 ◽  
Author(s):  
R. M. Matveevsky ◽  
V. M. Sinaisky ◽  
I. A. Buyanovsky
Keyword(s):  
Surface Layer ◽  
Critical Temperature ◽  
Boundary Lubrication ◽  
Retained Austenite ◽  
Temperature Stability ◽  
Mineral Oil ◽  
Lubricant Layer ◽  
Austenite Content ◽  
Boundary Lubricant

The results of investigations by various authors on the influence of retained austenite on seizure are briefly considered. Using as an example the investigation of the critical temperature of mineral oil in the friction of alloyed steels, it is shown that the temperature of destruction of the lubricant layer appreciably depends on the nature and content of the alloying elements and doe not strictly depend on the retained austenite content in the surface layer of steel specimens. Certain questions are considered—the influence of the contact geometry on the determination of the critical temperature in conditions of boundary lubrication, and the expediency of using austenite steel for investigating the temperature stability of lubricant layers.

The influence of lubricant rheology and surface topography in modelling friction at concentrated contacts

1998 ◽  
Vol 212 (6) ◽  
pp. 391-400 ◽  
Author(s):  
K. A. Blencoe ◽  
G. W. Roper ◽  
J. A. Williams
Keyword(s):  
Coefficient Of Friction ◽  
Surface Engineering ◽  
Mechanical Response ◽  
Molecular Surface ◽  
Lubricant Layer ◽  
Load Parameter ◽  
Boundary Lubricant ◽  
Boundary Film ◽  
Surface Profiles ◽  
Conventional Picture

The conventional picture of a boundary lubricant layer is of a film which exhibits mechanical properties more like a solid than a liquid. In this paper the influence that the form of the dependence of shear strength on pressure has on the overall friction coefficient of contacts exhibiting both model and measured surface profiles is examined quantitatively. The analysis can provide plots of coefficient of friction versus a service or load parameter which also includes some aspects of contact topography. The results indicate that variations in the macroscopic coefficient of friction which may occur as the load is varied have their roots in both the statistical nature of the surface and the mechanical response of the lubricating boundary film. The effect of running-in on friction and safe working loads can also be observed. The value of this analysis is that it attempts to combine the behaviour of films at molecular dimensions with the topography of surfaces measured at an engineering scale and so gives an indication of the full-size effects that can be achieved by chemical or molecular surface engineering.

scholarly journals Analysis of influencing factors that can cause errors in the application of modern methods of sliding bearing diagnostics in machine and electrical systems

2020 ◽  
Vol 68 (4) ◽  
pp. 845-876
Author(s):  
Nikola Žegarac
Keyword(s):  
Influencing Factors ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
Diagnostic Methods ◽  
Sliding Bearings ◽  
Sliding Bearing ◽  
Bearing Clearance ◽  
Bearing Diagnostics ◽  
Modern Methods ◽  
Vibration Parameters

Introduction/purpose: The paper presents the application of modern methods in the diagnostics of sliding bearings and the analysis of influencing factors that can cause errors in such an application. Possibilities to determine with certainty when and where problems affect sliding bearings during system operation are presented. It is also shown how the system will continue to function over time. Causes of failures and the manner of their elimination are predicted, as well as the time for planned maintenance of technical systems. Method: The new method solves the problem of sliding bearing diagnostics by measuring the dynamic trajectories of the sleeve in the sliding bearing and by measuring vibration parameters on the inner and outer surfaces of the technical system. The dynamic trajectories of the bearing sleeve are measured with non-contact probes; therefore, the centering of probes in relation to the geometric center of the bearing is very important. Vibration parameters, directly related to the clearance in the sliding bearing, are measured on the inner and outer surfaces of the system. The choice of vibration parameters and measuring points is very important. This method has a number of advantages over other diagnostic methods, as it is easy to access measuring points. Results: By measuring the dynamic trajectory of the sleeves in the plain bearing and vibration parameters on the inner and outer surfaces, the bearing clearance quantities are determined, including: normal condition, initial clearance size, its further increase, bearing clearance sizes, and the moment when the condition parameters are close to the upper limit of the permissible bearing clearance. Conclusion: New diagnostic methods and monitoring systems can be widely applied to: internal combustion engines, all piston machines, hydroelectric power plants, thermal power plants, processing plants, and many other systems.

scholarly journals Atomic force microscope investigation of the boundary-lubricant layer in articular cartilage

2010 ◽  
Vol 18 (7) ◽  
pp. 956-963 ◽  
Author(s):  
S.M.T. Chan ◽  
C.P. Neu ◽  
G. DuRaine ◽  
K. Komvopoulos ◽  
A.H. Reddi
Keyword(s):  
Articular Cartilage ◽  
Atomic Force Microscope ◽  
Lubricant Layer ◽  
Microscope Investigation ◽  
Atomic Force ◽  
Boundary Lubricant

scholarly journals Analysis of mechanical energy losses in marine diesels

2021 ◽  
Vol 5 (2(61)) ◽  
pp. 26-32
Author(s):  
Sergii Sagin ◽  
Volodymyr Madey ◽  
Tymur Stoliaryk
Keyword(s):  
Diesel Engines ◽  
Internal Combustion Engines ◽  
Structural Characteristics ◽  
Internal Combustion ◽  
Engine Oil ◽  
Lubricant Layer ◽  
Combustion Engines ◽  
Engine Oils ◽  
Boundary Lubricant ◽  
Marine Diesel

The object of research is marine diesel engine oils, which provide lubrication, cooling and separation of friction surfaces. The subject of the research is the process of ensuring minimum mechanical losses in marine diesel engines. A problematic point in ensuring the lubrication of the cylinder-piston group and motion bearings is the lack of analytical and experimental studies that establish the relationship between the structural characteristics of engine oils and mechanical losses arising in marine internal combustion engines. The degree of orientational ordering of molecules and the thickness of the boundary lubricating layer are considered as the structural characteristics of engine oils. The determination of these values was carried out using the optical method based on the anisotropy of the light absorption coefficient by the boundary lubricant layer and the isotropic volume of the liquid (engine oil). The assessment of the level of mechanical losses arising in marine diesel engines was carried out according to an indirect indicator – the overshoot of the rotational speed and the time to reach the steady state of operation in the event of a change in load. It has been experimentally established that for engine oils used in marine internal combustion engines, the thickness of the boundary layer can be 15–17.5 µm. Motor oils, which are characterized by a higher ordering of molecules and a thickness of the boundary lubricant layer, ensure the flow of transient dynamic processes with less overshoot and a shorter transient time. This ensures the level of minimal mechanical losses occurring in marine diesel engines. The technology for determining the structural characteristics of engine oils can be used for any type and grade of oil (mineral or synthetic; high or low viscosity; used in both circulating and cylinder lubrication systems). The method of indirect assessment of mechanical losses of marine diesel engines can be used for any types of internal combustion engines of ships of sea and river transport (low-, medium- and high-speed; as well as performing the functions of both main and auxiliary engines).

Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

1987 ◽  
Vol 45 ◽  
pp. 326-327
Author(s):  
A.K. Rai ◽  
A.K. Petford-Long ◽  
A. Ezis ◽  
D.W. Langer
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Almost Everywhere ◽  
Spacer Layer ◽  
Good Contact ◽  
The Relationship ◽  
Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

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