نتایج جستجو برای: friction time

تعداد نتایج: 1920712  

In some engineering fields, wear resistance and a low friction coefficient are required at the sametime. In this research, PTFE nanoparticles and carbon nanotubes were co-deposited within Ni-Pmatrix to obtain an Ni-P-PTFE-CNT hybrid coating for wear resistance and a low friction coefficient.The tribological properties of the deposits were evaluated by pin on disc tribometer. T...

1998
Chris Marone

This paper reviews rock friction and the frictional properties of earthquake faults. The basis for rateand state-dependent friction laws is reviewed. The friction state variable is discussed, including its interpretation as a measure of average asperity contact time and porosity within granular fault gouge. Data are summarized showing that friction evolves even during truly stationary contact, ...

2015
Philipp Damm Alwina Bender Georg Bergmann

Loosening of the artificial cup and inlay is the most common reasons for total hip replacement failures. Polyethylene wear and aseptic loosening are frequent reasons. Furthermore, over the past few decades, the population of patients receiving total hip replacements has become younger and more active. Hence, a higher level of activity may include an increased risk of implant loosening as a resu...

2008
Florian Schmid

A quasi-static contact problem is considered for a non-linear elastic system with finitely many degrees of freedom. Coulomb’s law is used to model friction and the friction coefficient may be anisotropic and may vary along the surface of the rigid obstacle. Existence is established following a time-incremental minimization problem. Friction is artificially decreased to resolve the discontinuity...

2007
G. Kweon T. E. Grift D. Miclet

nt matter & 2007 IAgrE. temseng.2007.02.013 thor. Tel.: +1 217 333 2854; : [email protected] (T.E. Gri This paper describes the development of a device capable of measuring the dynamic friction coefficient of particles accelerated in a tube spinning in a horizontal plane. The dynamic friction coefficient is not the classical Coulomb friction coefficient, but a lumped parameter influenced by the Co...

2008
José M. Sancho Aldo H. Romero Katja Lindenberg

The Kramers problem in the energy-diffusion limited regime of very low friction is difficult to deal with analytically because of the repeated recrossings of the barrier that typically occur before an asymptotic rate constant is achieved. Thus, the transmission coefficient of particles over the potential barrier undergoes oscillatory behavior in time before settling into a steady state. Recentl...

Journal: :The Journal of chemical physics 2008
Daniel Neuhauser Kenneth Lopata

Friction is a desired property in quantum dynamics as it allows for localization, prevents backscattering, and is essential in the description of multistage transfer. Practical approaches for friction generally involve memory functionals or interactions with system baths. Here, we start by requiring that a friction term will always reduce the energy of the system; we show that this is automatic...

2013
Aidong Deng Hao Cao Hang Tong Li Zhao Kang Qin Xi Yan

Friction fault diagnosis of rotating machinery based on acoustic emission (AE) technique is a research hotspot in recent years. The rotating machinery will produce multi-source noise during the operation process, so how to correctly identify the friction acoustic emission signals has become a key factor for accurate diagnosis of the fault. In this paper, it proposes a Gaussian mixed model (GMM)...

2016
C. Caroli B. Velicky

Unlike the well known Amontons-Coulomb laws of dry friction, the recent precise experimental studies of low velocity friction dynamics provide sensitive tests for a theoretical description. We introduce a model, in which the friction force originates from multistability induced by interactions of individual pairs of asperities whose properties undergo a slow time evolution due to plastic creep ...

2018
Cunao Feng Dekun Zhang Kai Chen Yongbo Guo

This paper aims to investigate the microscopic friction mechanism based on in situ microscopic observation in order to record the deformation and contact situation of friction lining during the frictional process. The results show that friction coefficient increased with the shear deformation and energy loss of the surfacee, respectively. Furthermore, the friction mechanism mainly included adhe...

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