Study On The Stick-slip Of Interfacial Friction Based On The Non-linear Oscillator

With the development of MEMS (micro electro mechanical system) and storage devices, more and more mechanical system parts working in the interface friction state. The micro friction behavior influences not only the performance but also the using life of the system. owing to the difference of friction characteristics between micro and macro, the researching and controlling of friction behave is particularly important. In the present paper, the main focus is paid on the influence that the sliding velocity> material parameters and temperature on stick-slip friction behave.Firstly, the dynamics model of stick-slip friction is established based on discrete energy dissipation. The simulation calculation results show that the stick-slip behavior is infulenced not only by lateral stiffness between atoms atomic mass and lattice constant, but also by the mass of the sliding part and the sliding speed. The smaller the lateral stiffness between atoms, atomic mass, lattice constant and the mass of the sliding part, the stronger the stick-slip behavior is. but the greater the sliding speed, the stronger the stick-slip behavior is during the friction.The, a non-linear elastic oscillator model of stick-slip friction during interfacial friction is established based on Lennard-Jones potential theory. The simulation calculation results show that the excitation force on the upper interface atom being is related to the interatomic potential and the lattice constants, and the stick-slip behavior is related to the excitation force, relative sliding velocity, block mass, system stiffness, damping coefficient and the real contact area. When the relative sliding velocity or real contact area increases, the stick-slip intensity increased; while the mass of the sliding block or system stiffness, damping coefficient increases, the stick-slip strength weakened. When the system stiffness or damping coefficient increases, the stick-slip frequency increases; while the mass of the sliding block increases, the stick-slip frequency decreased; the effects of the real contact area on the stick-slip frequency is not significant.Subsequently, a temperature rising model of the atomic vibration is established by the view of the relationship between the micro structure and the temperature in contact surface, the result indicated that, Considing single factor of atomic mass, the changing of atomic mass suppress friction interface temperature rising, and the higher of interface temperature the more significant of inhibitory effect. Considering the impact of atomic mass and atomic natural frequency, when the relative sliding velocity is small and the interface temperature is lower, the changing of atomic mass on the tribological activation is very small, but when the relative sliding speed is higher and the interface temperature is high, the changing of atomic mass has the positive activation obviously. Characteristics of crystal constant with temperature changes has the inhibition effect on tribological process, and the bigger the thermal expansion coefficient of crystal,the more obvious inhibition is.Finally, by using the atomic force microscope to test the friction of mica, silicon chips and quartz under interfacial friction. The regularities of the experiments are the same as the theoretical results, which indicate that the theory and method proposed in the present paper are reasonable.