Atomistic Modeling of Friction
نویسندگان
چکیده
Friction is a well-known, but poorly understood, phenomenon that affects virtually all aspects of daily life. In some cases, friction is desirable, e.g., high friction in clutches leads to the effective transmission of forces between an automobile’s engine and its wheels, while in other cases friction is a significant drawback, e.g., friction between the piston and cylinder wall decreases the efficiency of automobile engines. Although macroscopic friction laws were introduced a few centuries ago,1 and the existence of friction was recognized long before that, the underlying atomic-level mechanisms leading to friction have remained elusive. The identification of these mechanisms has emerged as a topic of significant interest, which has been driven by the miniaturization of mechanical devices, the peculiar behavior of condensed matter at the nanoscale, and advances in simulating chemically complex lubricants and surfaces with ever-increasing accuracy.2–4 Although a great deal of research has been directed towards elucidating the fundamental, atomic-level origins of friction in recent years, many key questions remain unanswered. Atomic-level simulation has been used extensively in the study of friction, not simply as a means of supplementing experimental studies, but as a powerful tool for gaining unique insight into the relevant processes. Indeed, simulations allow one to study well-defined systems under a variety of conditions that may be difficult, or even impossible, to examine in real laboratory experiments. As such, simulations have shed much-needed light on fundamental aspects of friction, and in some cases have even overturned conventional wisdom regarding the origins of friction. In this chapter,
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