Figure 4

Schematic illustrations of four different distributions of multi-asperity contacts on a frictional interface. (a) A reference state of contact with (N₁,r₁), where N and r are the number of asperities per unit area and the asperity radius, which give the contact area S=N π r² and the specific stiffness κ=N c E r of the interface. (b) Case with (N₂,r₂)=(N₁/I²,I r₁), (c) case with (N₃,r₃)=(J N₁,r₁), and (d) case with $(N_4,r_4)=(N_1,\sqrt{J}{r}_1)$. In each panel, also shown is the resultant (S _i ,κ _i ). Circles represent the population of asperity contacts and black portions represent the increased parts of the contact area with respect to Figure 4a. Here, plotting is done with (I,J)=(2,1.5).