On the contact between elasto-plastic media with self-affine fractal roughness

Modeling the elasto-plastic contact between rough interfaces may require high computational effort as real surfaces present broad roughness spectra. In this work, we propose an efficient multi-asperity model where each asperity follows Jackson and Green's equations and both coupling and coalescence of contact spots are considered. In agreement with previous studies, the contact area A is found to rise linearly with the applied load. Moreover, under the assumption of yield stress independent of the asperity size, no differences are found with respect to the elastic contact solution for nanometric root mean square (rms) roughness amplitudes hrms. On the contrary, for micrometric hrms, the slope of the area-load relation is observed to increase when reducing the yield strength crY. We have also investigated the effect of increasing the rms roughness gradient of the surface h ' rms by adding fine-scale wavelengths to the roughness spectrum. Due to plastic deformations, the contact area A is found to be independent of the high-frequency cut-off of the roughness spectrum as it converges when increasing the number of roughness scales.

Automated summary

In this study, an efficient multi-asperity model considering contact coupling and coalescence is proposed for modeling the elasto-plastic contact between rough interfaces. The results show that the contact area increases linearly with the applied load, and this relationship is affected by the yield strength and roughness amplitude. Additionally, the contact area is found to be independent of the high-frequency cut-off of the roughness spectrum due to plastic deformations.