###### Analytical Solution of Reynolds Equation: Grubin’s Approximation

Derivation of famous analytical solution of EHL equations is presented here. In 1949, Grubin obtained a solution for so called elasto-hydrodynamic lubrication (EHL) line contact problem with simplifications known as Grubin approximation. He was the […]

###### Coefficient of Friction

What is a Friction Coefficient? 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 […]

###### Elastohydrodynamic Lubrication (EHL): Theory and Definition

What is Elastohydrodynamic Lubrication (EHL)? Elastohydrodynamic Lubrication – or EHL – is a lubrication regime (a type of hydrodynamic lubrication (HL)) in which significant elastic deformation of the surfaces takes place and it considerably alters […]

###### Rolling Contact Fatigue

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, […]

###### Generalized Reynolds Equation: Derivation

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 Definition: Fatigue wear is a type of wear in which the surface damage of the material takes place due to strain-induced on the surface for a particular number of cycles to a certain […]

###### Greenwood and Williamson Contact Model

Surface roughness was recognized to play a major role in forming friction and transition from one lubrication regime to another [1]. Greenwood pioneered with first rough contact model in 1966 [2]. Inspired by this milestone […]

###### Wear Particles

The wear process results in generation of debris, or particles, of various size, shape, color distributions and chemical composition[1, 2, 3]. These distributions are dependent on normal load, sliding speed, environment and many other parameters[4]. […]

###### Corrosive Wear

Corrosive wear Definition: Corrosive wear is a type of wear in which the material surface gets disintegrated due to the chemical reaction between the material surface and the corroding medium which can be either a […]

###### Abrasive Wear

Definition:   Abrasive wear is the type of wear mechanism that results in the disintegration of the material on the surface due to the influence of the hard particle in contact with the surface. It […]