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)
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机译：我将讨论平面粗糙度在静摩擦和动摩擦之间的过渡中的作用，以平面粗糙弹性体与球形光滑玻璃表面接触为例[1]。随着剪切负荷的增加，数字图像相关技术可用于监测面内弹性体的变形。发现环形滑动区域与中央杆区域共存，逐渐侵入接触。这些局部测量的主要特征可以由Cattaneo和Mindlin（CM）的模型正确地捕获。然而，密切的比较显示出显着的差异，反映了CM场景背后过于简化的假设。特别是，我将证明，界面遵循了与粗糙度相关的长度尺度的类似弹塑性的摩擦定律，而不是CM模型中假设的刚性-塑性行为。我将根据为均匀加载的宏观多触点界面[2]导出的最新模型来讨论这种局部本构定律。 [1] A. Prevost，J。Scheibert G.Debrégeas，欧洲。物理J. E，出版中[2] L. Bureau，C. Caroli，T. Baumberger，Proc。A. R. Soc。伦敦459，2787（2003）
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