Surface effects on elastohydrodynamic lubrication contact of piezoelectric materials with non-Newtonian fluid

Abstract

By using surface piezoelectricity theory, this article investigates the elastohydrodynamic lubrication (EHL) line contact of a transversely isotropic piezoelectric half-plane with consideration of the surface effect under a rigid cylindrical punch. The surface effect in the surface piezoelectricity theory is mainly described by the following parameters: surface piezoelectric constant, surface dielectric constant, surface elastic constant, and residual surface stress. The punch is treated as the electrical insulator. The lubricant, whose viscosity and density are dependent on fluid pressure, is chosen as non-Newtonian fluid. Firstly, by analyzing the frictionless dry contact of piezoelectric materials with surface effect, dry contact pressure distribution and EHL film thickness equation are obtained. Then, an iterative method is proposed to get fluid pressure and film thickness at lubricant contact region by calculating the fluid-solid coupled nonlinear equations. Effects of surface dielectric constant, surface piezoelectric constant, surface elastic constant, residual surface stress, punch radius, entraining velocity, and slide/roll ratio on the film thickness and fluid pressure are examined. Our analysis indicates that surface effect has an essential effect on the EHL contact behaviors of piezoelectric materials at micro-/nano-scales.