22.05.2017 tribonet 341 Views
The ASTM definition of lubricating grease is: “A solid or semi-solid lubricant consisting of a thickener agent in a liquid lubricant. Other ingredients imparting special properties may be included” A commercial lubricating grease usually consists […]
Industrial Lubrication

What Are Lubricants?

17.04.2017 tribonet 865 Views
Definition Lubricant is a substance which is used to control (more often to reduce) friction and wear of the surfaces in a contact of the bodies in relative motion. Depending on its nature, lubricants are […]
Hydrodynamic Lubrication

Hydrodynamic Lubrication

16.02.2017 tribonet 1278 Views
Definition Hydrodynamic lubrication theory is a theory used to reduce friction and/or wear of rubbing solids with the aid of liquid lubricant. For a vast majority of the surfaces encountered in nature and used in […]
Elastic Deformation

Elastic Deformation

16.02.2017 tribonet 820 Views
Definition Elastic deformation is a change of the shape of the body as a reaction to applied stress. This deformation is only temporary and once the stress is released, the undeformed shape of the body […]


14.02.2017 tribonet 578 Views
Tribometers are the devices used to analyze and characterize tribological systems. The most common direct measurement is the measurement of friction coefficient (and shear strength). During the post processing stage other quantities can be measured, […]
Friction Coefficient

Coefficient of Friction

06.02.2017 tribonet 1154 Views
Friction is a force resisting relative motion and may occur at the interface between the bodies, but may also occur within the bodies. The concept of friction coefficient was first formulated by Leonardo da Vinci […]
EHL film meniscus

Elastohydrodynamic Lubrication (EHL)

05.02.2017 tribonet 1682 Views
Definition of EHL Elastohydrodynamic Lubrication – or EHL – is a type of hydrodynamic lubrication (HL) in which significant elastic deformation of the surfaces takes place and it considerably alters the shape and thickness of […]
Fatigue Surface Crack

Rolling Contact Fatigue

25.01.2017 Aydar Akchurin 1181 Views
Rolling-contact fatigue (RCF) is defined as a failure or material removal driven by crack propagation caused by the near-surface alternating stress field.  It is typically considered that if a bearing is properly mounted, aligned, lubricated, […]
Osborne Reynolds

Generalized Reynolds Equation: Derivation

14.01.2017 tribonet 908 Views
Reynolds equation is one of the fundamental equations of lubrication theory and tribology. In the simplest case, it considers incompressible and Newtonian lubricant. This model is sufficient to describe lubricant friction in some cases (relatively […]
Fatigue Wear

Fatigue Wear

08.01.2017 tribonet 804 Views
Fatigue wear is a type of wear where a number of cycles is needed to generate debris. The fatigue process in metals may induce the generation of surface and subsurface cracks, which after a critical […]