纳米圆柱体与平面粘着接触的分子动力学模拟

用分子动力学方法模拟了不同半径的刚性圆柱体压头与弹性基体的粘着接触过程。给出了接触力、静态结构因子及压头与基体最小间隙随压头位移的变化关系,以及接触区域的von Mises应力分布。结果表明,在突跳接触与接触分离时,随着压头尺寸的增大,粘着滞后现象越明显。高应力区出现在接触区域两边,且当压头半径减小时,von Mises应力随着压入深度的增大而迅速增大,说明粘着力对小尺寸压头的接触过程影响较大。

Applying Principles of Molecular Dynamics to Simulating Adhesive Contact between Nanocrystalline Cylindrical Probe and Plane

With the appearance of nanomaterial,the adhesive force between surfaces needs to be more closely scrutinized.We apply the principles of molecular dynamics to simulating the behavior of adhesive contact between rigid cylindrical probe and elastic half-space substrate,both consisting of copper nanocrystals. In the full paper,we explain in detail the application of the principles of molecular dynamics to our particular problem.In this abstract,we just add some pertinent remarks to listing the two topics of explanation.The first topic is: the model for rigid cylindrical probe and elastic half-space substrate.In the first topic,we devise the model according to the principles of molecular dynamics using the classical Lennard-Jones potential.Also in the first topic,we mention that the three probes we use have different radii of 10r0,20r0 and 30r0 respectively,where r0=0.227 7 nm according to Ref.2 authored by P.M.Agrawal et al. The second topic is: results and discussion.The four subtopics of the second topic are: the process of contact and separation(subtopic 2.1),the jump to contact and the adhesive hysteresis(subtopic 2.2),the zero-loading state and the pressure contact state(subtopic 2.3) and the von Mises stress distribution for each contact state(subtopic 2.4).In the second topic,there are figures in the full paper summarizing the calculation results,which indicate preliminarily that:(1) the adhesive hysteresis is more apparent with increasing radius of probe;(2) high von Mises stress regions exist at the edge of contact due to adhesion;(3) the maximum von Mises stress increases steeply during pressure contact with decreasing radius of probe.