%0 Journal Article
%A Dapp, Wolfgang
%A Müser, Martin
%T Contact mechanics of and Reynolds flow through saddle points: On the coalescence of contact patches and the leakage rate through near-critical constrictions
%J epl
%V 109
%N 4
%@ 0295-5075
%C Les Ulis
%I EDP Sciences
%M FZJ-2015-02409
%P 44001
%D 2015
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000351955600018
%R 10.1209/0295-5075/109/44001
%U https://juser.fz-juelich.de/record/189218