Cylinder-flat-surface contact mechanics during sliding

J. Wang, A. Tiwari, B. N.J. Persson*, I. M. Sivebaek

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Using molecular dynamics we study the dependency of the contact mechanics on the sliding speed when an elastic block (cylinder) with a cos(q0x) surface height profile is sliding in adhesive contact on a rigid flat substrate. The atoms on the block interact with the substrate atoms by Lennard-Jones potentials, and we consider both commensurate and (nearly) incommensurate contacts. For the incommensurate system the friction force fluctuates between positive and negative values, with an amplitude proportional to the sliding speed, but with the average close to zero. For the commensurate system the (time-averaged) friction force is much larger and nearly velocity independent. For both types of systems the width of the contact region is velocity independent even when, for the commensurate case, the frictional shear stress increases from zero (before sliding) to ≈0.1MPa during sliding. This frictional shear stress, and the elastic modulus used, are typical for polydimethylsiloxane rubber sliding on a glass surface, and we conclude that the reduction in the contact area observed in some experiments when increasing the tangential force must be due to effects not included in our model study, such as viscoelasticity or elastic nonlinearity.

Original languageEnglish
Article number043002
JournalPhysical Review E
Volume102
Issue number4
Number of pages6
ISSN2470-0045
DOIs
Publication statusPublished - 2020

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