A loading fractal prediction model developed for dry-friction rough joint surfaces considering elastic-plastic contact

In the microscopic view, the contact between two solid surfaces is reckoned to be the contact among asperities indeed. These asperities loaded which contact with each other are to experience three stages of deformation in succession: elastic deformation, elastic-plastic deformation, and plastic deformation, not the direct transition from elastic deformation to plastic deformation. In addition, these asperities should be distributed on the three-dimensional surface topography, and the corresponding fractal dimension is . In this study, firstly, based on the fractal theory and Hertz contact theory, the loading fractal model of rough dry-friction joint surfaces is established in consideration of elastic-plastic deformation of asperities and three-dimensional surface topography. Secondly, two important fractal parameters, fractal dimension D and fractal roughness G, can be calculated according to sampled surface topography of 45 steel and power spectrum density function method. Then, the effects of friction factor , fractal dimension D, and fractal roughness G on the loading fractal model are analyzed by numerical simulation. Finally, the present model is compared with experimental data and other models, which indicates that their trends are the same. The elastic-plastic loading modeling provides a certain theoretical reference for the accurate solution of contact among rough surfaces.