Effect of surface parameters on finite element method based deterministic Gaussian rough surface contact model

Abstract

Three-dimensional rough surface contact models enrich the understanding of the influence of surface texture in rough surface contacts. Most of the existing contact models did not consider the effect of elasto-plastic deformation and neighboring asperity interactions for the rough surface contact analysis, or only to a limited extent. In the present work, three-dimensional contact analyses of Gaussian rough surfaces are carried out using finite element method. By fast Fourier transform approach, Gaussian rough surfaces having auto-correlation lengths of 0.5, 2.0, 5.0, and 10 µm and surface roughness of 0.001, 0.01, and 0.1 µm are generated. The generated rough surfaces are transferred to finite element method based ANSYS package for micro-contact analysis. The continuity of elastic, elasto-plastic, and plastic deformations of near realistic feature-based asperities and effects of asperity interactions are inherently included in the present analysis. Each rough surface contact analysis is carried out in such a manner to cover the entire asperity distribution with incremental displacements. The contact load, real area of contact, and contact pressure are extracted from each analysis. The results showed that the surface having low surface roughness, the asperities deform mostly elastically whereas in medium and high surface roughness surfaces, the elasto-plastic and plastic deformation of asperities are significant and also in low auto-correlation length surface, the intensification of sub surface stresses cause the mean contact pressure ratio to reach peak value whereas in high auto correlation length surface, the larger size of asperities and the neighboring asperity interaction keep the mean contact pressure ratio at low level.