The inhomogeneous distribution of surface asperities generated by deformation induces variability in the friction and initiates strain localizations during metal forming. The friction literature generally does not account for the strong influence localized variations in material properties have on the friction behavior. A prototype apparatus was developed that measures the friction behavior und...

The paper deals with experimental friction identificat ion method of a DC motor. For precise positioning tasks a friction phenomenon plays a large problem. For this a friction has to be identified and subsequently compensated if it is important. At first the paper deals with basic friction models. In the next section the DC motor mathemat ical model is stated. The DC motor friction identificat ...

This paper describes a new friction model, called the “brush model“, suitable for haptic rendering in virtual environments. A novel two-layer multiasperity surface contact model is presented that provides real-time rendering of friction forces at haptic refresh rates. This new friction model has several advantages; of particular importance is the accuracy with which it handles static friction a...

Friction is responsible for several servomechanism limitations, and their elimination is always a challenge for control engineers. In this paper, model-based feedback compensation is studied for servomechanism tracking tasks. Several kinetic friction models are employed and their parameters identified experimentally. The effects of friction compensation on system response are examined using des...

The friction welding of Zr55Al10Ni5Cu30 bulk metallic glasses (BMG) has been tried. An apparatus for the friction welding of BMGs adopting a pneumatic cylinder and gripper based on a conventional lathe, and a welding process which provides a sufficient cooling rate after welding were devised. Friction time and friction pressure were chosen as the control parameters in the friction welding proce...

Aim: To evaluate the effect of ligation method on friction and the efficacy of the new slick elastomeric modules (TP Orthodontics, USA) and slide elastomeric modules (Leone Orthodontics, Italy) which claim to reduce friction at the module/wire interface. Materials and methods: Slick and slide modules were compared with regular modules, modules tied in figure of eight fashion, tight stainless st...

Orthodontic tooth movement can be regarded as teeth sliding on a wire like pearls on a string, the force being supplied by springs or elastics. The movement implies friction between wire and bracket, taking up part of the force and leaving an uncontrolled amount to act on the teeth. The friction is likely to depend on bracket construction and wire material. Therefore, in this investigation the ...

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 ...

In this paper, we investigate the sliding friction and wear behavior of a hydrogenated diamond-like carbon (DLC) film in ultrahigh vacuum (UHV) and under partial pressures of water vapor, oxygen, nitrogen and hydrogen. The initial friction coefficient of the film in UHV was 0.15, but decreased steadily to values as low as 0.03 after about 30 sliding passes. During longer duration tests, the fri...

To clarify the friction durability, both during and after the high-temperature heating of nanometer-thick diamond-like carbon (DLC) films, deposited using filtered cathodic vacuum arc (FCVA) and plasma chemical vapor deposition (P-CVD) methods, the dependence of the friction coefficient on the load and sliding cycles of the DLC films, were evaluated. Cluster-I consisted of a low friction area i...