Model for contact between finger and sinusoidal plane to evaluate adhesion and deformation component of friction

• We modelled the adhesion and deformation component of friction.
• Topography on nanolevel had influence on friction.
• The model can be used to estimate friction on similar surfaces.

One of the main parameters affecting finger friction, friction-induced vibrations in the finger, and consequently tactility is surface topography. Recently Skedung et al. performed finger friction measurements on fine controlled surfaces. These surfaces were sinusoidal with wavelengths from 0.27 to 8.8 µm and amplitudes from 0.007 to 6 µm. Building on those tests an analytical model for the contact was developed to explain the differences in friction coefficient. The contact was modelled as trapezoids in a circular pattern pressed against a sinusoidal plane. Results showed that the calculated contact area and therefore friction coefficient corresponded well with the measurements. This model can be used to see how the different surface parameters influence friction.