以界面摩擦为研究对象,探讨了基于耦合振子模型(coupled-oscillator model)的滑动摩擦微观机理,分析了滑动过程中的能量耗散问题.采用Maugis-Dugdal接触模型替代界面摩擦中的Lennard-Jones势能,并将该模型融入耦合振子模型之中,通过计算振子在一个周期内的能量增加值,推导出了界面摩擦力的理论计算公式.理论分析表明,对于探针-试样接触系统,滑动摩擦力近似随着法向载荷的2/3次方增加,这与纳米摩擦学经典理论是相符的.理论计算结果与超高真空原子力显微镜镀铜探针在Cu(111)晶面扫描实验结果符合良好,表明本文提出的理论和方法可行.
A new model named the coupled-oscillator model, in which the relationship of the lateral force and the normal force are considered, is proposed for studying the interfacial friction. The Maugis-Dugdal model is used to approximately substitute the Lennard-Jones potential of the interfacial friction in the new model. Then, the formulas for frictional force calculation are deduced. Comparison between the theoretical results and the experimental data obtained by an atomic force microscope shows that the model and the formulas are practically feasible. Based on the coupled-oscillator model, it is found that the frictional force increases approximately with the 2/3th power of the normal force for a tip-sample contact system, which is the same as the classical conclusion of nano-tribology.