Milne Zachary B, Hasz Kathryn, McClimon J B, Castro Juan, Carpick Robert W
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA.
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
Philos Trans A Math Phys Eng Sci. 2022 Sep 19;380(2232):20210342. doi: 10.1098/rsta.2021.0342. Epub 2022 Aug 1.
Several key features of nanoscale friction phenomena observed in experiments, including the stick-slip to smooth sliding transition and the velocity and temperature dependence of friction, are often described by reduced-order models. The most notable of these are the thermal Prandtl-Tomlinson model and the multibond model. Here we present a modified multibond (mMB) model whereby a physically-based criterion-a critical bond stretch length-is used to describe interfacial bond breaking. The model explicitly incorporates damping in both the cantilever and the contacting materials. Comparison to the Fokker-Planck formalism supports the results of this new model, confirming its ability to capture the relevant physics. Furthermore, the mMB model replicates the near-logarithmic trend of increasing friction with lateral scanning speed seen in many experiments. The model can also be used to probe both correlated and uncorrelated stick slip. Through greater understanding of the effects of damping and noise in the system and the ability to more accurately simulate a system with multiple interaction sites, this model extends the range of frictional systems and phenomena that can be investigated. This article is part of the theme issue 'Nanocracks in nature and industry'.
实验中观察到的纳米尺度摩擦现象的几个关键特征，包括从黏滑到平滑滑动的转变以及摩擦对速度和温度的依赖性，通常由降阶模型来描述。其中最著名的是热普朗特 - 汤姆林森模型和多键模型。在此，我们提出一种改进的多键（mMB）模型，通过一个基于物理的判据——临界键伸长长度来描述界面键的断裂。该模型明确纳入了悬臂和接触材料中的阻尼。与福克 - 普朗克形式体系的比较支持了这个新模型的结果，证实了它捕捉相关物理现象的能力。此外，mMB模型再现了许多实验中观察到的摩擦随横向扫描速度增加的近对数趋势。该模型还可用于探究相关和不相关的黏滑现象。通过更深入了解系统中阻尼和噪声的影响以及更准确模拟具有多个相互作用位点的系统的能力，这个模型扩展了可研究的摩擦系统和现象的范围。本文是主题为“自然与工业中的纳米裂纹”的一部分。
