| Abstrakt: |
In this research, the friction between the contact surfaces was modeled and simulated with random distribution of roughness in Nano scale. For this purpose, firstly the modified AMM friction model was derived for the contact between smooth flat/ rough flat surfaces on the basis of JKR contact model, HK friction model and random distribution of Greenwood-Williamson (GW) model. According to the results of simulation, the modified AMM friction model predict more value for the friction force considering Nano scale surface interaction forces, and it also has more accuracy in comparison to the initial AMM model. In the following, the obtained model was extended for evaluating the friction between smooth spherical/rough flat surfaces and finally the friction between the tip of Atomic Force Microscopic on the rough surface, then the effects of geometric parameters of surface included of standard deviation of asperities' height and radius of asperities' peak on the magnitudes of normal load, friction force and finally friction coefficient between atomic force microscopic tip and rough surface has been investigated. The achieved results demonstrate that normal force and friction force both will raise by rising of standard deviation of asperities' height while as friction coefficient will decrease. Furthermore, the normal and friction forces and also friction coefficient will increase by increase of roughness' peaks radius. It is also observed that the effects of standard deviation of asperities' height on friction parameters is more than the effects of asperities' peaks radius. [ABSTRACT FROM AUTHOR] |
