Figure 1

Time evolution of the shear force and the instantaneous and local densities of the real contact area.

(a) The shear force and (b) the instantaneous and local densities of the real contact area are shown for V = 0.4 mm/s, h = 10 mm and F_z = 400 N. The inset of (a) displays an enlarged view of F_x near t = 5 s. The arrows indicate when local precursor slipping occurs, the vertical broken lines show when bulk sliding occurs and the red circles denote where local precursor slipping stops.