نتایج جستجو برای: temperature dependent friction

تعداد نتایج: 1136870  

Analysis of intrinsic irreversibility and heat transfer in a buoyancy-driven changeable viscosity liquid along an incline heated wall with convective cooling taking into consideration the heated isothermal and isoflux wall is investigated. By Newton’s law of cooling, we assumed the free surface exchange heat with environment and fluid viscosity is exponentially dependent on temperature. Appropr...

2013
Philip Egberts Robert W. Carpick

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...

2012
Mohammad Ali Khasawneh Robert Y. Liang

Both short-term and long-term variations have been observed in measured friction on pavement surface. These variations have been attributed to different factors, such as traffic, rainfall and temperature. Due to the fact that Hot Mix Asphalt (HMA) pavement surface and rubber tires are viscoelastic materials, it is believed that temperature may affect the measured frictional properties. Some res...

2016
S. Golovin I. Golovin V. Seleznev

Kinetic dependence of martensitic transformation and properties changes in Fe-24%Ni5%Mo alloys with different carbon content have been obtained. Internal friction method was used for the precise investigation of structural changes after austenization, during martensitic transformation at sub zero temperature and during the postheat. The influence: (i) of frequency of oscillations, (ii) rate of ...

Journal: :Nanotechnology 2008
Kwang-Seop Kim Yasuhisa Ando Kyung-Woong Kim

Adhesion and friction tests were carried out in order to investigate the effect of temperature on the tribological characteristics of poly(methylmethacrylate) (PMMA) film using AFM. The pull-off and friction forces on the PMMA film were measured under a high vacuum condition (below 1 × 10(-4) Pa) as the temperature of the PMMA film was increased from 300 to 420 K (heating) and decreased to 300 ...

Journal: :journal of nanostructures 2013
s. a. hashemizadeh v. rafee

in this paper, for the first time we have studied theoretically the effect of exchange-correlation holes around electrons in gaalas/gaas/gaalas nanostructure on the temperature-dependent dynamic dielectric function of two-dimensional electron gas by employing random phase, stls and hubbard approximations. also, we have investigated another interesting system which is coupled quantum wells struc...

2009
J. SERVANTIE David Andrieux Sébastien Viscardy Eric Gerritsma Nathan Goldman

The objective of this PhD thesis was the study of friction in carbon nanotubes by analytical methods and molecular dynamics simulations. The goal of this research was to characterize the properties of friction in nanotubes and from a more general point of view the understanding of the microscopic origin of friction. Indeed, the relative simplicity of the system allows us to interpret more easil...

2017

It is shown that the exhibition of smooth sliding and relaxation oscillations, or 4 stick-slips under conditions of boundary lubrication, when frictional forces are measured by the deflexion of an elastic system, may be explained as due to the dependence of kinetic friction on velocity. In the cases giving smooth sliding, kinetic friction decreases as velocity decreases, at very low speeds; for...

1999
Tuğrul Özel Taylan Altan

This paper presents a methodology to determine simultaneously (a) the flow stress at high deformation rates and temperatures that are encountered in the cutting zone, and (b) the friction at the chip–tool interface. This information is necessary to simulate high-speed machining using FEM based programs. A flow stress model based on process dependent parameters such as strain, strain-rate and te...

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