Probing the micromechanics of a multi-contact interface at the onset of frictional sliding
Résumé
I will discuss the role of surface roughness on the transition between static and kinetic friction, on the example of a flat rough elastomer in contact with a spherical smooth glass surface [1]. Digital Image Correlation is used to monitor the in-plane elastomer deformation as the shear load is increased. An annular slip region is found to progressively invade the contact, in coexistence with a central stick region. The main features of these local measurements are correctly captured by Cattaneo and Mindlin (CM)'s model. However, close comparison reveals significant discrepancies that reflect the oversimplifying hypothesis underlying CM's scenario. In particular I will show that, instead of the rigid-plastic behavior assumed in CM's model, the interface obeys an elasto-plastic-like friction law involving a roughness-related length scale. I will discuss this local constitutive law in the light of a recent model derived for homogeneously loaded macroscopic multi-contact interfaces [2]. [1] A. Prevost, J. Scheibert G. Debrégeas, Eur. Phys. J. E, in press [2] L. Bureau, C. Caroli, T. Baumberger, Proc. R. Soc. London 459, 2787 (2003)
Domaines
Mécanique [physics]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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