Tangential force during displacement

Figure 1. Evolution of the tangential force during the displacement of the sample at constant velocity (v = 400 nm. s ) Stiction effect.

Figure 8. A) Tangential force during the displacement of the sample at a constant velocity of 5 nm.s and a periodic solicitation with an amplitude of+/-2.5 nm at 4 Hz. B) Variation of the characteristic length of the contact area and of the continuous part of the tangential force obtained from response A).

The principle of a scratch experiment is to move an indentor into a topcoat while the sample is translated perpendicular to the indentor motion. During the process, the force parallel to indentor motion (Normal force) and force parallel to sample motion (Tangential force), the displacements of indentor and sample are controlled or measured with high resolution and fast dynamic response. In addition, other controllable parameters are penetration rate, scratch rate, lubrication condition, cutting geometry and temperature. 

The mobility distribution in static packings of bidisperse frictional disks depends on tbe treatment of the tangential contact forces during the packing-generation procedure. Three variants of the Cundall-Strack model cf. Section 6.2.2) are used. In the first (method 1), the relative tangential displacement (,... 

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