Dissipative Properties of EHD Lubricant Film

For the case of the failure of the lubricant film at hydrodynamic lubrication a common thermodynamic theory of strength is considered. According to this theory the failure occurs when the internal energy density (potential and thermal components) in the volume of material reaches a constant for a given material. A special case of this theory is considered when only the density of heat (kinetic) component of internal energy is taken into account. Temperature condition determines the limit state for liquid lubricants - mineral oils. When analyzing the regularities of friction at EHD lubrication the state and properties of the oil film at the condition of irregular and hydrostatic compression. The original structural model of oil film at EHD lubrication in the form of the rotary oscillating cells with elastic interactions to each other is proposed. It is similar to the Rayleigh-Benard cells and corresponds to the cellular hypothesis of J. Gibbs for the case of equilibrium and reversible process. It is quite possible that the size of the cells have an order of about nano level. The oil film dissipates energy in the direction of relative motion of bodies. This oil film has the highest dissipative properties.