نتایج جستجو برای: frictional soils

تعداد نتایج: 55503  

2017
Mohamed Ahmed Salim

Frictional resistance is an important counterforce to orthodontic tooth movement during sliding mechanics. This study was carried out to evaluate the effect of ceramic bracket and ceramic bracket with metal slot -archwire‐ ligation combinations on “resistance to sliding” during simulated canine retraction on typodont model. The frictional resistance was tested between Ceramic brackets (3MUNITEK...

Journal: :Journal of Experimental and Theoretical Physics Letters 2002

Journal: :Journal Of Geophysical Research: Solid Earth 2023

Frictional interfaces lose stability via earthquake-like ruptures, which are close analogues of shear cracks that well-described by fracture mechanics. Interface however, need to be first formed—or nucleated. Rupture nucleation therefore determines the onset friction, replacing concept a characteristic “static friction coefficient”. Utilizing rupture arrest at an imposed barrier, we experimenta...

2010
S. Henkes M. van Hecke

While frictionless spheres at jamming are isostatic, frictional spheres at jamming are not. As a result, frictional spheres near jamming do not necessarily exhibit an excess of soft modes. However, a generalized form of isostaticity can be introduced if fully mobilized contacts at the Coulomb friction threshold are considered as slipping contacts. We show here that, in this framework, the vibra...

2009
HERIBERT BLUM

In this paper, we study mixed variational nite element methods for the unilateral problems arising in contact mechanics.The presented discrete spaces can handle the case of non matching meshes in the contact area. We rst state the static problem and then extend it to the frictional contact case, and end with the dynamic frictional problem.

Journal: :iranian journal of materials forming 2014
sh. molaei m. shahbaz r. ebrahimi

frictional shear stress is usually determined by utilizing the coefficient of friction or the constant friction factor models. the present study deals with finite element analysis of double cup extrusion process to determine the relationship between constant friction factor (m) and coefficient of friction (µ), since the metal flow in this process is very sensitive to frictional conditions. ther...

Journal: :international journal of robotics 0
farid sheikholeslam isfahan university of technology shahram hadian jazi shahrekord university mehdi keshmiri isfahan university of technology

there have been many researches on object grasping in cooperating systems assuming no object slippage and stable grasp and the control system is designed to keep the contact force inside the friction cone to prevent the slippage. however undesired slippage can occur due to environmental conditions and many other reasons. in this research, dynamic analysis and control synthesis of a cooperating ...

2007
S. C. Bellemare M. Dao S. Suresh

Indentation hardness has been used extensively for material characterization and many recent computational studies have established quantitative relationships between elasto-plastic mechanical properties and the response in instrumented indentation. In contrast, very few studies have systematically quantified the effect of the plastic deformation characteristics on the frictional sliding respon...

Journal: :European journal of orthodontics 2009
Giancarlo Cordasco Giampietro Farronato Felice Festa Riccardo Nucera Elena Parazzoli Giovanni Battista Grossi

The aim of this in vitro study was to evaluate the frictional forces between bracket and archwire that included three passive self-ligating brackets (Damon SL2 SDS). The brackets were individually bonded to a brass mount using a preformed 0.021 x 0.025 inch stainless steel wire jig in order to exclude adverse tipping or torsion. The central bracket was positioned 1 mm higher than the others, in...

Journal: :The journal of contemporary dental practice 2011
Nadeem Husain Avinash Kumar

AIM The purpose of this investigation was to determine the kinetic frictional resistance offered by stainless steel and Titanium bracket used in combination with rectangular stainless steel wire during in vitro translatory displacement of brackets. MATERIALS AND METHODS In this study. Brackets: (All brackets used had a torque of - 7° and an angulation of 0°): (1) Dynalock (Unitek) 0.018'' slo...

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