%0 Journal Article
%T Probing locally the onset of slippage at a model multi-contact interface
%A V. Romero
%A E. Wandersman
%A G. Debr¨¦geas
%A A. Prevost
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevLett.112.094301
%X We report on the multi-contact frictional dynamics of model elastomer surfaces rubbed against bare glass slides. The surfaces consist of layers patterned with thousands spherical caps (radius of curvature 100 $\mu$m) distributed both spatially and in height, regularly or randomly. Use of spherical asperities yields circular micro-contacts whose radius is a direct measure of the contact pressure distribution. In addition, optical tracking of individual contacts provides the in-plane deformations of the tangentially loaded interface, yielding the shear force distribution. We then investigate the stick-slip frictional dynamics of a regular hexagonal array. For all stick phases including the initial one, slip precursors are evidenced. They are found to propagate quasi-statically, normally to the iso- pressure contours. A simple quasi-static model relying on the existence of interfacial stress gradients is derived and predicts qualitatively the position of slip precursors.
%U http://arxiv.org/abs/1311.1690v1