Analysis of minimum oil film thickness EHL elliptical contacts using multilevel methods

Hamrock and Dowson developed a simplified expression for influences of ellipticity parameter, dimensionless speed, load, and material parameters on minimum film thickness. However, by using a multilevel method, Ehret showed that his numerical results have a large difference compared with the simplified expression under point contact (ball-on-a-plate configuration). This paper has developed a new simplified expression. The influence of the ellipticity parameter, the dimensionless speed, load, and material parameters on minimum Min thickness is investigated from a low-pressure level (0.35 GPa) to high-pressure level (3.43 GPa). The ellipticity parameter is varied from 1 to 8. The dimensionless speed parameter is varied over a large range. The dimensionless load parameter is varied over a range of four orders of magnitude. Conditions corresponding to the use of solid materials of bronze, steet, and silicon nitride and lubrications of paraffinic and naphthenic mineral oils are considered for the dimensionless material parameter. Four hundred different cases are calculated for the new simplified expression.