Steady State EHL Line Contact Analysis with Surface Roughness and Linear Piezo-viscosity

Abstract

A special form of hydrodynamic lubrication, elastohydrodynamic lubrication (EHL), is generally encountered in mechanical components involving highly stressed non-conformal contact such as gears, cams, roller bearing etc. EHL is characterized with substantial elastic deformation of the interacting surface and piezo-viscous rise in lubricant viscosity which assist largely in evolution of load carrying fluid film.In the current paper, the effect of surface roughness of different magnitude in EHL line contact on pressure distribution is considered. At the same time graph between film thickness with rolling direction is plotted which gives reader the knowledge of EHL film thickness. Steady state effect of EHL with linear piezo-viscosity response at low pressure is taken into consideration. Full isothermal, Newtonian simulation of the EHL problem is discussed. It investigate the pressure distribution of sinusoidal waviness in the line contact, more precisely it study the effect of linear piezo-viscous fluid on surface roughness of different amplitude in steady state EHL line contact. Graphs plotted gives the clear idea to the designers, the behaviour of surface roughness with several amplitude and wavelength by linear piezo-viscous liquid like 2, 3-Dimethylpentane, L7808 (high temperature lubricant) and water/glycol solution of two water percentage and exponential fluid like santotrac 40 (S 40).The Reynolds equation, which governs the generation of pressure in the lubricated contact, is discretized using finite differences and solved along with the load balance equation using Newton-Raphson technique. A computer code is developed for implementation of solution algorithm. The results are obtained to study the linear and exponential piezo-viscous effect on surface roughness on the EHL characteristics.