TY  - JOUR
AU  - Dapp, Wolfgang
AU  - Müser, Martin
TI  - Contact mechanics of and Reynolds flow through saddle points: On the coalescence of contact patches and the leakage rate through near-critical constrictions
JO  - epl
VL  - 109
IS  - 4
SN  - 0295-5075
CY  - Les Ulis
PB  - EDP Sciences
M1  - FZJ-2015-02409
SP  - 44001
PY  - 2015
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000351955600018
DO  - DOI:10.1209/0295-5075/109/44001
UR  - https://juser.fz-juelich.de/record/189218
ER  -