  This paper advances an analytical incremental contact model for the purely
elastic or elastic-perfectly plastic Gaussian rough surfaces. The contact is
modelled by the accumulation of identical circular contacts with radius given
by the total truncated area at varying heights divided by the contact patch
number. The contact area-load relationship is derived analytically, showing
approximate linearity for the contact fraction up to 10%. Good agreement is
found between the new proposed model and the direct finite element simulations.
To characterize the influence of plastic deformation, a dimensionless
plasticity parameter is introduced as the ratio of yield strain to root mean
square gradient of the rough surface. It is demonstrated that the general
elastic-plastic contact response would approach to the limit of purely elastic
as the plasticity parameter increases.
