Experimental evidence of non-Amontons behaviour at a multi-contact interfaceJ. Scheibert1, A. Prevost1, J. Frelat2, P. Rey3 and G. Debrégeas1
1 Laboratoire de Physique Statistique de l'ENS, UMR 8550, CNRS/ENS/Université Paris 6/Université Paris 7 24 rue Lhomond, F-75231 Paris, France, EU
2 Laboratoire de Modélisation en Mécanique, UMR 7607, CNRS/Université Paris 6 4 place Jussieu, F-75252 Paris, France, EU
3 CEA-LETI - 17 rue des Martyrs, F-38054 Grenoble Cedex 09, France, EU
received 21 January 2008; accepted in final form 16 June 2008; published August 2008
published online 23 July 2008
We report on normal stress field measurements at the multicontact interface between a rough elastomeric film and a smooth glass sphere under normal load, using an original MEMS-based stress-sensing device. These measurements are compared to Finite-Elements Method (FEM) calculations with boundary conditions obeying locally Amontons' rigid-plastic-like friction law with a uniform friction coefficient. In dry contact conditions, significant deviations are observed which decrease with increasing load. In lubricated conditions, the measured profile recovers almost perfectly the predicted profile. These results are interpreted as a consequence of the finite compliance of the multicontact interface, a mechanism which is not taken into account in Amontons' law.
46.55.+d - Tribology and mechanical contacts.
81.40.Pq - Friction, lubrication, and wear.
85.85.+j - Micro- and nano-electromechanical systems (MEMS/NEMS) and devices.
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