Natural contacting surfaces have remarkable surface mechanical properties, which has led to the development of bioinspired surface structures using rubbery materials with strongly enhanced adhesion and static friction. However, sliding friction of structured rubbery surfaces is almost always significantly lower than that of a flat control, often due to significant loss of contact. Here we show ...

We demonstrate measurement and control of nanoscale single-asperity friction by using cantilever probes featuring an in situ solid-state heater in contact with silicon oxide substrates. The heater temperature was varied between 25 and 790 °C. By using a low thermal conductivity sample, silicon oxide, we are able to vary tip temperatures over a broad range from 25 ± 2 to 255 ± 25 °C. In ambient ...

BACKGROUND Friction between archwires and brackets is assuming greater importance for finishing with increased use of sliding mechanics in orthodontics as friction impedes the desired tooth movement. The following study is conducted to compare and evaluate the effect of ligation on friction in sliding mechanics using 0.022" slot bracket in dry condition. MATERIALS & METHODS In the study 48 co...

In this paper, by applying analytical method and using experimental method data, the effect of sliding velocity on friction coefficient for contact of copper with copper is investigated. Some equations for obtaining friction coefficient as a function of sliding velocity for contact of copper with copper by applying second analytical method and using experimental method data are achieved. The re...

Friction and wear, often treated as unrelated, distinct phenomena, are manifestations of the same dissipative physical processes occurring at sliding interfaces. Friction force dissipates power and generates entropy. Wear irreversibly changes a material structure, often with loss of material. Associated with both friction and wear is production of irreversible entropy by interfacial dissipative...

Friction, lubrication, and wear have a strong influence on the performance and behavior of mechanical systems. This paper deals with different friction models for sliding contacts running under different conditions. The models presented are suited to different situations, depending on the type of contact, running conditions, and the behavior of interest. The models will be discussed from simula...

Discussions of energy dissipation during friction processes have captured the attention of engineers and scientists for over 300 years. Why then do we know so little about either dissipation or friction processes? A simple answer is that we cannot see what is taking place at the interface during sliding. Recently, however, devices such as the atomic force microscope have been used to perform fr...

We describe herein how a quartz crystal microbalance (QCM) can be used to measure wetting behavior and sliding friction levels of adsorbed films and a brief summary of the status of the fundamental energy dissipative mechanisms that give rise to friction in these systems. The relation between sliding friction values, diffusion coefficients, and film lubricity is next described. Finally, as a sp...

Everyone learns the basics of friction in high-school physics classes: the friction force experienced by a sliding object is proportional to the normal force that an object exerts on a surface. Remarkably, this extremely simple and empirical relation, known as Amontons’ Law, is still often used in creating the most technologically sophisticated machines and devices, even though friction is know...

The mismatched perturbations and system chattering are the two main challenging problems in sliding mode control. This paper tries to solve these problems by deriving the invariant sets created by the sliding mode controller where the present work is devoted to a second order nonlinear affine system. If the state started in these sets it will not leave it for all future time. The first invarian...