EHL OF COATED SURFACES .2. NON-NEWTONIAN RESULTS

A complete non-Newtonian elastohydrodynamic lubrication solution for m ultilayered elastic solids is introduced in this paper. A modified for m for the Reynolds equation was derived by incorporating the circular non-Newtonian fluid model associated with a limiting shear strength di rectly into the momentum equations that govern the instantaneous equil ibrium of a fluid element inside the lubricated conjunction. The modif ied Reynolds equation, the elasticity equations of multilayered elasti c half-space, the lubricant pressure-viscosity equation, the lubricant pressure-density equation, and the load equilibrium equation were sol ved simultaneously by using the system approach. The effects of the su rface coating on pressure profiles, film shapes, and surface shear str ess profiles are shown. Furthermore, the effects of coating thickness on the minimum film thickness and on the coefficient of friction are p resented for different coating materials. The results show that for ha rd coatings non-Newtonian fluid effects on the pressure profiles and f ilm shapes are significant because of the increase in the contact pres sure.