Unloading contact mechanics analysis of elastic–plastic fractal surface

• Published in: Archive of applied mechanics (1991) 2021-06, Vol.91 (6), p.2697-2712
• Main Authors: Pan, Wujiu, Song, Changxuan, Ling, Liangyu, Qu, Haoyong, Wang, Minghai
• Format: Article
• Language: English
• Subjects: Asperity; Classical Mechanics; Deformation mechanisms; Dissipation factor; Elastic analysis; Elastic deformation; Energy dissipation; Engineering; Fractal analysis; Fractal geometry; Fractal models; Fractals; Friction factor; Hysteresis loops; Original; Plastic deformation; Prediction models; Theoretical and Applied Mechanics; Three dimensional models; Two dimensional models
• ISSN: 0939-1533; 1432-0681
• DOI: 10.1007/s00419-021-01918-0

At present, there are many researches on the loading between contact surfaces, but it is also very important to predict the unloading process between rough surfaces. In this paper, based on the three-dimensional fractal loading model we built earlier and the unloading finite element results of the single asperity by Etsion et al., the unloading fractal prediction model between rough contact surfaces is established. The model takes into account the friction factor between surfaces, the three-dimensional fractal characteristics of rough surfaces and the elastic–plastic deformation mechanism of asperities. The model is compared with the unloading model based on the two-dimensional fractal curve established by Miao et al. and the finite element results. The results show that the unloading process between rough surfaces depends on the final loading state of the surface; the loading and unloading curves form a hysteresis loop, which represents the energy dissipation in a contact cycle; both the friction factor and fractal dimension of the contact surface have important effects on the unloading model.