纳米级粗糙表面接触行为的分子动力学模拟

Molecular Dynamics Simulation of Contact Mechanics Between Nanoscale Rough Surfaces

为了研究纳米级粗糙表面接触的微观机理,以金刚石为例,采用Tersoff势,用分子动力学方法研究了具有分形粗糙表面的刚性球形探头与弹性平面的接触过程。模拟结果显示,探头的表面形貌是影响趋近阶段粘附力的重要因素,分形维数越大,粘附力越大;探头的表面形貌对载荷-位移曲线也有影响,载荷较小时,探头表面粗糙形貌显著影响载荷的增长规律,载荷较大时,表面形貌对载荷-位移曲线变化的影响不再显著,载荷与位移线性增长;探头表面的纳米级粗糙峰,显著地影响了探头与基体之间的接触行为。但这种改变,并不会影响接触过程中真实接触面积与法向载荷间的线性关系。

We adopted large-scale molecular dynamics simulations with Tersoff potential to establish contact mechanics between nanoscale rough surfaces.Nominally spherical tips with fractal rough surfaces were pressed into atomic smooth diamond substrates.It shows that surface morphology of tip is the critical factor of the adhesion and normal force in the event of the small normal force,and the adhesion force is increased with the fractal dimension of surface.At the large normal force,the critical factor of normal lo...