On the Shear Bands and Shear Localizations in EHL Films

Liquid lubricants in elastohydrodynamic lubrication (EHL) are subjected to high pressures of the magnitude of 10⁹ N/m² (GPa). Under these high pressures, the lubricants in room temperatures are usually in the glassy state behaving as amorphous solids. Similar to the polymers, the lubricants exhibit elastic or visco-elastic behavior under low-shear-stress loading and plastic or visco-plastic behavior with high shear stresses. Recent laboratory experiments have revealed two types of localized shear responses that can take place in the lubricant bulk. The localized shear may be active in the EHL film and may play a significant role in the responses exhibited by the contact conjunction. A typical example is the EHL traction. This paper summarizes the up-to-date research related to the shear localizations.