纳米薄膜润滑的分子动力学模拟

Molecular dynamics simulations of the nano-scale thin film lubrication

针对广泛存在于微机电系统和精密机械中的纳米薄膜润滑问题,首先建立了作为润滑剂的正十六烷长链分子间的作用力模型;接着运用分子动力学模拟的方法得到了润滑剂在6种不同的剪切速率下的应力、速度和温度分布;研究了摩擦过程中特殊的物理现象.结果表明:随着剪切速率的变化,润滑剂的温度和所受到的剪切应力不断变化;润滑剂的分层和层间滑移现象在各种剪切速率下都会发生,是纳米薄膜润滑中的普遍现象.此研究对理解和研究纳米润滑薄膜的作用机理有促进作用.

To research the nano - scale thin film lubrication which consists widely in micro electro mechanical systems and precision instruments, firstly, an interaction model of long chain molecules hexadecane, used as lubrication, was built. Then the distribution of shear stresses, velocities and temperatures of the lubrication at six different shear velocities were obtained by the molecular dynamics simulations. Some special physical phenomena in the shear were investigated also. The results show that with the change of the shear velocity, the temperatures and shear stresses of the lubricant vary continuously. The phenomena of the delamination and the slippage between layers of the lubricant appeared at each shear velocity, which occur in the nano -scale thin film lubrication. This work could promote the understanding and research of the mechanism of the nano -scale thin film lubrication.