Central film thickness prediction for line contacts under pure impact

The lubricant film thickness in lubricated rolling contacts can be predicted quantitatively, thanks to the work of Dowson, Higginson, Hamrock and others. However, most industrial applications are governed by time dependent operating conditions. For the most extreme time dependent case (impact), no film thickness predictions exist. The current work derives a dimensionless Reynolds line contact equation based on the Johnson dry contact impact analysis. It is shown that similar to the film thickness under rolling conditions, the Piezoviscous Elastic impact problem is governed by only 2 parameters. The numerical results are curve fitted to obtain a central film thickness predictive equation.