原子尺度摩擦行为的分子动力学模拟  

MOLECULAR DYNAMICS SIMULATIONS OF ATOMIC-SCALE FRICTION BEHAVIOR

作　　者：段芳莉[1] 刘静[1] 杨继明[1] 

机构地区：[1]重庆大学机械传动国家重点实验室,重庆400030

出　　处：《固体力学学报》2014年第2期167-172,共6页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金项目(50875271);重庆大学机械传动国家重点实验室科研业务费(SKLMT-ZZKT-2012MS 18)资助

摘　　要：应用大规模分子动力学方法,模拟了具有原子级光滑和原子级粗糙形貌的刚性球形探头与弹性平面基体的干摩擦行为,研究了无/有粘附条件下的载荷与摩擦力、载荷与真实接触面积,以及摩擦力与真实接触面积之间的关系,对纳米尺度下的摩擦行为规律进行了分析.几种系统的真实接触面积-载荷关系都与相应的连续力学接触模型定性的一致,它们分别是Hertz光滑表面接触模型、Greenwood-Williamson粗糙表面接触模型和Maugis-Dugdale粘着接触模型.无论是由光滑表面还是粗糙表面构成的摩擦系统,在无粘附条件下摩擦力与载荷成正比,而摩擦力与真实接触面积之间没有一个简单的关系;在粘附条件下摩擦力与真实接触面积成正比,而摩擦力与载荷之间表现为Maugis-Dugdale模型预测的亚线性关系.研究表明,当表面作用从无粘附到粘附时,控制摩擦力的决定因素从载荷转变为接触面积,摩擦行为从载荷控制摩擦转变为粘着控制摩擦.The friction behaviors between rigid spherical tips with different atomic scale rough topog raphy and the elastic flat substrate are simulated using large scale molecular dynamics method . The rela tionships between the friction and load, real contact area and load, friction and real contact area are analyzed for both non adhesion and adhesion cases to study the friction behavior laws on nanometer scale. The re- suits show that the relations between real contact area and load of the studied systems all agree well with the corresponding continuum contact models,such as Hertz smooth contact model,Greenwood Williamson rough contact model and Maugis Dugdale adhesive contact model. For the non-adhesive contacts, the fric- ＊ion-load relations are linear for both smooth and rough surface system, while there is no simple relation- ship between the friction and real contact area. However, the relationships between the friction and real contact area are linear for the adhesive contacts, while the friction-load relations are sublinear and agree well with the prediction from Maugis Dugdale model. Our research shows that when it is changed from non-adhesive to adhesive surface, the decisive factor of friction will transfer from load to contact area, and the friction behavior will transfer from load controlled friction to adhesion controlled friction.

关 键 词：摩擦行为 粘附 原子尺度 分子动力学模拟 

分 类 号：O561[理学—原子与分子物理]