Towards a modeling of the time dependence of contact area between solid bodies

E. A. JAGLA

JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT

IOP PUBLISHING LTD

Lugar: Londres; Año: 2010 vol. 2010 p. 1 - 18

1742-5468

I present a simple model of the time dependence of the contact area between solid bodies, assuming either a totally uncorrelated surface topography or a self-affine surface roughness. Time-dependent deformation due to ´creep´ processes is incorporated using a recently proposed model, which produces the time increase of the contact area A(t). For an uncorrelated surface topography, A(t) is numerically found to be well fitted by expressions of the form , where the exponent q depends on the normal load FN as q ∼ F Nβ, with β close to 0.5. In particular, when the contact area is much smaller than the nominal area I obtain A(t)/A(0) ∼ 1 + Cln(t/t0 + 1), i.e. a logarithmic time increase of the contact area, in accordance with experimental observations. The logarithmic increase for low loads is also obtained analytically in this case. For the more realistic case of self-affine surfaces, the results are qualitatively similar.