A Research of V-Belt Transmission Mechanics with Two Same Pulleys

2010 ◽  
Vol 450 ◽  
pp. 357-360 ◽  
Author(s):  
Qing Bao Wei ◽  
Xin Chen ◽  
Da Yu Zheng
Keyword(s):  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Mechanical Analysis ◽  
Belt Drive ◽  
Equilibrium Equations ◽  
Elasticity Limit ◽  
Friction Forces ◽  
The Coefficient Of Friction ◽  
Groove Structure ◽  
Belt Transmission

V-belt is made of a special anisotropic material, its material and pulley groove structure make the V-belt drive mechanics complicated. The elasticity limit, seating and unseating effects, radial compliance makes us consider the macro features of the drive and not to consider the material heterogeneity. We focus on the steady mechanics of V-belt drive in the state of sliding friction between groove and belt. The pulley groove leads to two-dimensional radial and tangential friction forces whose direction depends on the relative speed between belt and the pulley along the contact arc. The belt model is analyzed with comparing method which is performed through acquiring the equivalent coefficient of friction, and replacing the coefficient of friction in the flat belt mechanical equilibrium equations for v-belt analysis. Through the sample calculation it is proved that this method is simple and valid for V-belt mechanical analysis.

scholarly journals Solid Lubrication by Multiwalled Carbon Nanotubes in Air and in Vacuum for Space and Aeronautics Applications

2005 ◽  
Author(s):  
K. Miyoshi ◽  
K. W. Street ◽  
R. L. Vander Wal ◽  
R. Andrews ◽  
David Jacques ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Solid Lubrication ◽  
Multiwalled Carbon ◽  
Solid Lubrication Friction ◽  
The Coefficient Of Friction ◽  
Dry Conditions ◽  
Steel Balls

To evaluate recently developed aligned multiwalled carbon nanotubes (MWNTs) and dispersed MWNTs for solid lubrication applications, unidirectional sliding friction experiments were conducted with 440C stainless steel balls and hemispherical alumina-yttria stabilized zirconia pins in sliding contact with the MWNTs deposited on quartz disks in air and in vacuum. The results indicate that MWNTs have superior solid lubrication friction properties and endurance lives in air and vacuum under dry conditions. The coefficient of friction of the dispersed MWNTs is close to 0.05 and 0.009 in air and in vacuum, respectively, showing good dry lubricating ability. The wear life of MWNTs exceeds 1 million passes in both air and vacuum showing good durability. In general, the low coefficient of friction can be attributed to the combination of the transferred, agglomerated patches of MWNTs on the counterpart ball or pin surfaces and the presence of tubular MWNTs at interfaces.

scholarly journals Anisotropic Vibration Tactile Model and Human Factor Analysis for a Piezoelectric Tactile Feedback Device

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 448 ◽  
Author(s):  
Jichun Xing ◽  
Huajun Li ◽  
Dechun Liu
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Ciliary Body ◽  
Human Factor ◽  
Sliding Friction ◽  
Excitation Frequency ◽  
Tactile Feedback ◽  
Body Structure ◽  
Full Coverage ◽  
The Coefficient Of Friction

Tactile feedback technology has important development prospects in interactive technology. In order to enrich the tactile sense of haptic devices under simple control, a piezoelectric haptic feedback device is proposed. The piezoelectric tactile feedback device can realize tactile changes in different excitation voltage amplitudes, different excitation frequencies, and different directions through the ciliary body structure. The principle of the anisotropic vibration of the ciliary body structure was analyzed here, and a tactile model was established. The equivalent friction coefficient under full-coverage and local-coverage of the skin of the touch beam was deduced and solved. The effect of system parameters on the friction coefficient was analyzed. The results showed that in the full-coverage, the tactile effect is mainly affected by the proportion of the same directional ciliary bodies and the excitation frequency. The larger the proportion of the same direction ciliary body is, the smaller the coefficient of friction is. The larger the excitation frequency is, the greater the coefficient of friction is. In the local-coverage, the tactile effect is mainly affected by the touch position and voltage amplitude. When changing the touch pressure, it has a certain effect on the change of touch, but it is relatively weak. The experiment on the sliding friction of a cantilever touch beam and the experiment of human factor were conducted. The experimental results of the sliding friction experiment are basically consistent with the theoretical calculations. In the human factor experiment, the effects of haptic regulation are mainly affected by voltage or structure of the ciliary bodies.

The development of wear-protective oxides and their influence on sliding friction

1980 ◽  
Vol 369 (1739) ◽  
pp. 557-574 ◽  
Keyword(s):  
Metal Oxide ◽  
Coefficient Of Friction ◽  
Metal Surfaces ◽  
Sliding Friction ◽  
Constant Thickness ◽  
Partial Pressures ◽  
Metal Wear ◽  
The Coefficient Of Friction ◽  
Metal Wear Particles ◽  
Clean Metal

The friction behaviour of iron and Fe-Cr alloys in unidirectional and reciprocating sliding motions at 293 K has been examined in oxygen of controlled partial pressure. During sliding, a progressive decrease in coefficient of friction accompanies the development of compacted oxide films on the metal surfaces, eventually resulting in a steady value of about 0.6 when almost complete oxide coverage is attained. This is achieved more rapidly at higher oxygen partial pressures. A model to account for the experimental observations is proposed, based on the growth of oxide on the clean metal surfaces and metal wear particles between each wear traversal and the removal of that oxide during the subsequent traversal. The oxidized debris is fragmented further and compacted on to the metal surfaces to form a layer of nominally constant thickness, the area of which increases progressively with the number of sliding traversals. The model relates the coefficient of friction to the area of compacted oxide in terms of several interfacial metal, oxide and metal-oxide parameters. The importance of some of these parameters on the frictional behaviour is discussed in light of the experimental observations.

ON THE FRICTION OF INFLATED RUBBER TIRES ON ICE

1958 ◽  
Vol 36 (5) ◽  
pp. 599-610 ◽  
Author(s):  
C. D. Niven
Keyword(s):  
Friction Force ◽  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Rolling Friction ◽  
The Other ◽  
Slow Speed ◽  
Dry Ice ◽  
Load Axis ◽  
Cold Room ◽  
The Coefficient Of Friction

The friction on ice of some small inflated rubber tires was measured on a turntable in a cold room. When rolling-friction force was plotted against load, the relation was either linear or slightly curved away from the load axis; such curvature implies that Thirion's Law does not hold for rolling friction. On the other hand when sliding-friction force was plotted against load the curvature was toward the load axis as would be expected if Thirion's Law applied. The coefficient of friction can go as low as 0.01 or even lower for a hard-pumped tire when the temperature is near 0 °C, but at −1 °C. rolling friction on dry ice is quite appreciable. The results refer only to measurements at very slow speed.

Plowing Friction Under Harmonic Normal Loads

1999 ◽  
Vol 121 (2) ◽  
pp. 282-285 ◽  
Author(s):  
D. P. Hess
Keyword(s):  
Shear Strength ◽  
Coefficient Of Friction ◽  
Metal Surfaces ◽  
Sliding Friction ◽  
Normal Load ◽  
Hard Materials ◽  
Lubricated Contacts ◽  
Highly Nonlinear ◽  
Average Coefficient ◽  
The Coefficient Of Friction

The influence of harmonic normal loads on sliding friction is investigated through analysis of contacts consisting of conical and spherical sliders of hard materials on softer metal surfaces. Friction for such contacts is assumed to result from a plowing component and a shearing component. Calculations and experiments show that the coefficient of friction is essentially independent of normal load for contacts with conical sliders. However, for spherical sliders the relation between the coefficient of friction and normal load is highly nonlinear. In the presence of harmonic variations in normal load, this non-linearity causes a shift in the average coefficient of friction. For ideal lubricated contacts, the shearing component of friction is very small and for this case, it is shown that the maximum average reduction in the coefficient of friction is ten percent. When the shearing component is more significant, as with dry contacts, the shift is less. For example, when the shear strength is one-sixth the hardness of the softer material, the maximum average reduction in the coefficient of friction is five percent.

Tribological properties of structural alloys for the heat exchange equipment parts subjected to fretting

2020 ◽  
pp. 401-407
Author(s):  
E.A. Marchenko ◽  
M.M. Khrushchov ◽  
S.M. Kaplunov ◽  
V.A. Panov
Keyword(s):  
Stainless Steel ◽  
Heat Exchange ◽  
Titanium Alloys ◽  
Fatigue Fracture ◽  
Coefficient Of Friction ◽  
Wear Mechanism ◽  
Sliding Friction ◽  
Adhesive Interaction ◽  
Heat Exchange Equipment ◽  
The Coefficient Of Friction

Trobological characteristics of sliding friction in stainless steel and titanium alloys in dry and water lubricated conditions have been determined. The character of the coefficient of friction variation with load and the duration of tests have confi rmed the prevailing wear mechanism in these materials to be frictional fatigue fracture that in the case of titanium alloys is accompanied with adhesive interaction and plastic plowing. The frictional fatigue curves built in a result of this investigation make possible to estimate the materials tribological longevity.

Experimental Studies of Deformation and Temperature Processes Mandrelling in the Deform-3D System

2021 ◽  
Vol 1037 ◽  
pp. 357-368
Author(s):  
Mikhail F. Selemenev ◽  
Arkady A. Cherepenko ◽  
Elena A. Zvyagina ◽  
Artem N. Tkachenko ◽  
Elena M. Selemeneva
Keyword(s):  
Heat Transfer ◽  
Coefficient Of Friction ◽  
Experimental Studies ◽  
Contact Stresses ◽  
Temperature Analysis ◽  
Friction Forces ◽  
The Coefficient Of Friction ◽  
Cutting Zone ◽  
Deform 3D

The article discusses the effect of epilamated coatings during mandrelling. The picture of the change in contact stresses in the DEFORM-3D system is presented. It was established that a decrease in the coefficient of friction from 0.9 to 0.6 leads to a decrease in the number of foci and areas of contact stresses, as well as temperature analysis showed that a decrease in the friction forces reduces heat transfer in the cutting zone by about 40 ° C.

Influence of the characteristics surface layer of the tool and composition technological lubricant on the coefficient of friction in methods combined mandreling of holes

2020 ◽  
pp. 331-336
Author(s):  
А.V. Shchedrin ◽  
А.А. Bekaev ◽  
N.Yu. Chikhacheva
Keyword(s):  
Surface Layer ◽  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Metal Coating ◽  
The Coefficient Of Friction ◽  
Technological Lubricant ◽  
Combined Methods

The influence of the nature and parameters microgeometry of the surface layer tool on the sliding friction coeffi cient in the combined methods opening under the conditions of using metal-coating lubricants, which implement the effect of wear-free friction of Garkunov—Kragelsky, is studied comparatively using the theoretical provisions of the adhesivedeformation theory of friction

Mechanics and Sliding Friction in Belt Drives With Pulley Grooves

2005 ◽  
Vol 128 (2) ◽  
pp. 494-502 ◽  
Author(s):  
Lingyuan Kong ◽  
Robert G. Parker
Keyword(s):  
System Analysis ◽  
Sliding Friction ◽  
General Purpose ◽  
Computational Technique ◽  
Belt Drive ◽  
Friction Forces ◽  
Belt Drives ◽  
Contact Points ◽  
Torque Loss ◽  
Axially Moving

The steady mechanics of a two-pulley belt drive system are examined where the pulley grooves, belt extension and wedging in the grooves, and the associated friction are considered. The belt is modeled as an axially moving string with the tangential and normal accelerations incorporated. The pulley grooves generate two-dimensional radial and tangential friction forces whose undetermined direction depends on the relative speed between belt and pulley along the contact arc. Different from single-pulley analyses, the entry and exit points between the belt spans and pulleys must be determined in the analysis due to the belt radial penetration into the pulley grooves and the coupling of the driver and driven pulley solutions. A new computational technique is developed to find the steady mechanics of a V-belt drive. This allows system analysis, such as speed/torque loss and maximum tension ratio. The governing boundary value problem (BVP) with undetermined boundaries is converted to a fixed boundary form solvable by a general-purpose BVP solver. Compared to flat belt drives or models that neglect radial friction, significant differences in the steady belt-pulley mechanics arise in terms of belt radial penetration, free span contact points, tension, friction, and speed variations.

Clot friction variation with fibrin content; implications for resistance to thrombectomy

2017 ◽  
Vol 10 (1) ◽  
pp. 34-38 ◽  
Author(s):  
Gillian M Gunning ◽  
Kevin McArdle ◽  
Mahmood Mirza ◽  
Sharon Duffy ◽  
Michael Gilvarry ◽  
...  
Keyword(s):  
Blood Cell ◽  
Coefficient Of Friction ◽  
Red Blood Cell ◽  
Sliding Friction ◽  
Imaging Techniques ◽  
Static Friction ◽  
Cell Content ◽  
Content Ratio ◽  
Custom Made ◽  
The Coefficient Of Friction

BackgroundDespite significant advancements in the procedural efficacy of mechanical thrombectomy in patients with ischemic stroke in recent years, there still remains a portion of the population that does not achieve good recanalization. The reasons for this may be varied. We hypothesized that static friction between the clot and the vessel, or catheter wall might contribute to the difficulty in removing the clot.ObjectiveTo determine if there is a relationship between clot composition and the resistance to sliding (friction) which might contribute to resistance to clot removal.MethodsAs clot composition can vary significantly, we investigated five different types of clot in order to measure their respective frictional properties. To do this, a custom-made testing apparatus was created, consisting of various replaceable low-friction surfaces on which the clots could be placed. The surface was then gradually tilted until the clots began to slide; the angle at which this occurred is related to the coefficient of friction of the clots. The experiment was repeated on a bovine aortic surface in order to confirm the results.ResultsWe found that fibrin-rich clots (<20% red blood cell content) have a significantly higher coefficient of friction than clots with a red blood cell content >20%. This result was confirmed by repeating the experiment on a bovine aortic surface as a representation of the interaction between clots and the arterial wall.ConclusionsThe friction properties of clots were found to be related to the content ratio of fibrin to red blood cells. Future imaging techniques that could show fibrin and red blood cell content might help us to predict the ‘stickiness’ of a clot.

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