title: Boundary lubrication of heterogeneous surfaces and the onset of cavitation in frictional contacts.
abstract: Surfaces can be slippery or sticky depending on surface chemistry and roughness. We demonstrate in atomistic simulations that regular and random slip patterns on a surface lead to pressure excursions within a lubricated contact that increase quadratically with decreasing contact separation. This is captured well by a simple hydrodynamic model including wall slip. We predict with this model that pressure changes for larger length scales and realistic frictional conditions can easily reach cavitation thresholds and significantly change the load-bearing capacity of a contact. Cavitation may therefore be the norm, not the exception, under boundary lubrication conditions.
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany.
authors.forename: Daniele
authors.identifier: 0000-0003-1908-2379
authors.initials: D
authors.lastname: Savio
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany.; Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center μTC, Wöhlerstraße 11, 79108 Freiburg, Germany.
authors.forename: Lars
authors.identifier: 0000-0001-8351-7336
authors.initials: L
authors.lastname: Pastewka
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany.; Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center μTC, Wöhlerstraße 11, 79108 Freiburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Gumbsch
mesh_terms: D000465:Algorithms; D008153:Lubrication; D008962:Models, Theoretical; D011312:Pressure; D013314:Stress, Mechanical; D013499:Surface Properties
keywords: Boundary lubrication; cavitation; confined fluid; molecular Dynamics; reynolds equation; surface heterogeneity; tribology; wall slip