The Asperities Density and Height Distribution Combined Effect on Rough Elastic Bodies Contact Characteristics

Abstract

The combined effect of the asperities density and their height distribution in contact of the rough rigid and smooth elastic half-spaces is investigated, taking into account the mutual influence of contact spots and statistical nature of the height distribution of asperities. The normal and exponential types of the height distribution of asperities with various densities and the dispersions of their height distribution are used in calculations of the contact characteristics at macroscale (the approach of contacting bodies and the relative contact area under given normal pressure) and the microscale (real contact pressure distributions). The obtained results are compared with ones calculated from the simplified models neglecting the mutual influence of individual contact spots. It is shown that neglecting the mutual influence of asperities in contact, which is made in many models of the discrete contact, can lead to significant errors in determining the contact characteristics on both the macro- and microscales. Based on the asymptotic analysis the analytical expressions for the approach of the contacting bodies and the relative contact area were derived and used for analysis of the microgeometry parameters effects on the rigid rough half-space penetration into the elastic half-space at high nominal pressures.