• Media type: E-Article
  • Title: Contact mechanics of and Reynolds flow through saddle points: On the coalescence of contact patches and the leakage rate through near-critical constrictions
  • Contributor: Dapp, Wolfgang [Author]; Müser, Martin [Author]
  • Published: EDP Sciences, 2015
  • Published in: epl 109(4), 44001 (2015). doi:10.1209/0295-5075/109/44001
  • Language: English
  • DOI: https://doi.org/10.1209/0295-5075/109/44001
  • ISSN: 0295-5075; 1286-4854
  • Origination:
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  • Description: We study numerically local models for the mechanical contact between two solids with rough surfaces. When the solids softly touch either through adhesion or by a small normal load L, contact only forms at isolated patches and fluids can pass through the interface. When the load surpasses a threshold value, $L_{\text{c}}$ , adjacent patches coalesce at a critical constriction, i.e., near points where the interfacial separation between the undeformed surfaces forms a saddle point. This process is continuous without adhesion and the interfacial separation near percolation is fully defined by scaling factors and the sign of $L_{\text{c}}-L$ . The scaling leads to a Reynolds flow resistance which diverges as $(L_{\text{c}}-L)^{-\beta}$ with $\beta = 3.45$ . Contact merging and destruction near saddle points become discontinuous when either short-range adhesion or specific short-range repulsion are added to the hard-wall repulsion. These results imply that coalescence and break-up of contact patches can contribute to Coulomb friction and contact aging.
  • Access State: Open Access