Self-affine roughness effects on the contact area between elastic bodies

Abstract

We have calculated the real contact area between elastic bodies with self-affine rough surfaces, which are described in terms of analytical correlation models in Fourier space. It is found that the roughness has a strong influence on the real contact area A(λ) at lateral length scales λ which are comparable with the in-plane roughness correlation length ξ, and for significant applied loads σo beyond the linear regime (or A∝σo). The effect of the roughness exponent H can be rather complex, depending on the relative magnitude of the roughness correlation length ξ with respect to the lateral length scale λ where the contact area is considered. Finally, we also show that descriptions of the influence of the roughness that is only based on power law approximations of the self-affine roughness spectrum are rather insufficient, especially for large roughness exponents H (>0.5).