Abstract
Objective To study the interaction relationship and discipline between atoms in interface friction process. Methods A non-linear elastic oscillator model of stick-slip friction during interfacial friction was established based on Lennard-Jones potential theory, then alpha Fe crystal was taken as an example and simulation experiment was conducted. Results Under the condition of hypothesis, the main vibration frequency of the mass was 16 Hz; the macro velocity equaling to v = 1×10 -3 m / s was the critical value of the increase of main amplitude values. The stick-slip frequency and main vibration frequency increased respectively along with the augment of the stiffness and damping coefficient in the ranges of 1. 0 ~ 100 N / m and 1. 0×10 -4 ~ 1. 0×10 -1 N / (m / s), respectively. When the real contact area of friction interface ranged from 1. 0×10 -18 to 1. 0×10 -14 m2 , increasing the normal pressure of friction interface caused the augment of stick-slip intension. The simulation calculation results showed that the excitation force on the upper interface atoms was related to the interatomic potential and the lattice constants, and the stick-slip behavior was related to the excitation force, relative sliding velocity, block mass, system stiffness, damping coefficient and the real contact area. Conclusion When the relative sliding velocity or real contact area increased, the stick-slip intensity increased. When the mass of the sliding block or system stiffness, damping coefficient increased, the stick-slip strength was weakened. When the system stiffness or damping coefficient increased, the stick-slip frequency increased. When the mass of the sliding block increased, the stick-slip frequency decreased. The effects of the relative sliding velocity and the real contact area on the stick-slip frequency were not significant.
Key words
L-J potential; non-linear elastic oscillator; damping; stiffness; stick-slip; interfacial friction
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GONG Zhong-liang, ZHOU Cheng-bo, PENG Yuan-zheng.
Dynamics of Stick-slip on Interfacial Friction Based on the Lennard-Jones Potential Theory[J]. Surface Technology. 2015, 44(9): 36-42
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Funding
Supported by the National Natural Science Foundation of China (51405036), the Natural Science Foundation of Hunan Province (11JJ3060), the Science and Technology Project of Hunan Province (2012GK3144), and Scientific Innovation Fund for Graduate of Central South University of Forestry and Technology(CX2015B22)