Particle entrapment in elliptical, elastohydrodynamic, rough contacts and the influence of intermolecular (van der Waals) forces

Abstract

The entrapment/rejection process of spherical, rigid microparticles in elliptical, rough elastohydrodynamic contacts is modelled. An earlier model of the author is extended to include van der Waals intermolecular forces, in addition to mechanical (reaction and friction) and fluid–particle forces. Surface roughness effects are also introduced in terms of the intermolecular force formulation and in the microscale friction (particle–asperity) sub-model. Possibilities related to particle entry into a contact are quantified by weight factors and performance indices. A total entrapment index is defined and linked to the probability of particle entrapment. A parametric analysis investigates the effect of the intermolecular particle force on the entrapment probability by varying the contact load, lubricant viscosity, elastic modulus of the contacting solids, contact velocity and the macroscopic (Coulomb) coefficient of friction.

Molecular dynamics analysis of friction-triggering process with spherical probe

“…The interaction distance of van der Waals force ranges from 0.1 nm to 1 nm [29,30] in the friction contact process at the mesoscopic scale. In figure 1(a), the depth of the spherical indenter pressed into the workpiece along the Z-[001 ¯] direction is denoted by d, which was defined as 1.2 nm to generate a contact force and simulate the sliding friction contact process of the 3D probe.…”