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.

Analysis of sliding friction of WC-Co composite on particleboard

2020 ◽  
Vol 111 ◽  
pp. 60-67
Author(s):  
Jacek Wilkowski ◽  
Marek Barlak ◽  
Radosław Jałocha ◽  
Zbigniew Werner ◽  
Alicja Auriga
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Roughness Parameter ◽  
Average Increase ◽  
Average Coefficient ◽  
Before And After ◽  
The Coefficient Of Friction ◽  
Nano Size

Analysis of sliding friction of WC-Co composite on particleboard. The paper presents the analysis of the coefficient of friction at the contact area between WC-Co composite and particleboard. The four types of WC-Co composite in the form of milling indexable knives for wood materials machining were tested. The tests were carried out on a linear reciprocating tribotester (pin-on-flat), where the sample was the clearance surface of WC-Co indexable knives and the counter-sample was made of three-layer particleboard. Before and after tribological tests, the surface roughness of tested knives was measured. The highest values of friction coefficient were obtained for the type UMG04 of cemented carbide - with nano size of WC grains and the lowest content of cobalt. The average coefficient of friction for selected types of WC-Co correlated with the average increase in surface roughness (the roughness parameter Ry).

Experimental study on the relationship between the friction coefficient and interference in locomotive axle press-fitting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Friction Pair ◽  
Rolling Stock ◽  
Content Type ◽  
Press Fitting ◽  
The Press ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Locomotive Wheels

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.

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.

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.

The Size of the Friction Coefficient Depending on the Size and Course of Normal Load

2014 ◽  
Vol 474 ◽  
pp. 303-308 ◽  
Author(s):  
Eva Labašová
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Testing Machine ◽  
Constant Load ◽  
Current Component ◽  
Rectangular Shape ◽  
The Coefficient Of Friction ◽  
Ring Method ◽  
Run Up

The coefficient of friction for the bronze material (CuZn25Al6) with inset graphite beds is investigated in the present paper. Friction coefficient was investigated experimentally by the testing machine Tribotestor`89 which uses the principle of the ring on ring method. Tribotestor`89 machine may be classed to the rotary tribometers. The tested sliding pairs were of the same material. The internal bushing performed a rotational movement with constant sliding speed (v = 0.8 m s-1). The external fixed bushing was exposed to the normal load, which was of different sizes and different variations. Process of load was increased from level 50 N to 200 N (400 N, 600 N) during run up 600 s, after the run up the appropriate level of load was held.The forth test had a rectangular shape of loading with direct current component 400 N and the amplitude 200 N period 600 s, the whole test took 1800 s. The obtained results reveal that friction coefficient decreases with the increase of normal load. Further, that the coefficient of friction was found smaller at constant load, as compared to rectangular shape of loading.

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.

scholarly journals Research of the drawing of bars plate in the refiners

2021 ◽  
Vol 2094 (4) ◽  
pp. 042038
Author(s):  
S N Vikharev ◽  
VA Morkovin
Keyword(s):  
Friction Coefficient ◽  
Contact Interaction ◽  
Coefficient Of Friction ◽  
Wood Pulp ◽  
Contact Processes ◽  
Low Concentration ◽  
The Coefficient Of Friction ◽  
Radial Arrangement

Abstract Object of research of article is the drawing of bars plate in the refiners at refining of chips and wood pulp. On the basis of the theory of contact interaction of bars influence of the drawing of plate on characteristics of contact processes is investigated. The friction coefficient between plate decreases at increase in density of contact of bars. At increase in an angle of crossing of bars rotor and stator and refining of pulp with concentration up to 6% the coefficient of friction decreases. At increase in an angle of crossing of bars chips and pulp with concentration over 10% the coefficient of friction increases. Therefore it is recommended to increase the angle of crossing of bars rotor and stator at refining of pulp of low concentration, and at refining of pulp of concentration over 10% and chips - to reduce, up to a radial arrangement.

THE INFLUENCE OF UNIAXIAL COMPRESSION ON THE FRICTION COEFFICIENT (POLYMER–STEEL PAIR), WEAR, AND HARDNESS IN SELECTED THERMOPLASTICS

Tribologia ◽  
2018 ◽  
Vol 279 (3) ◽  
pp. 77-82 ◽  
Author(s):  
Maciej KUJAWA
Keyword(s):  
High Pressure ◽  
Wear Resistance ◽  
Friction Coefficient ◽  
Uniaxial Compression ◽  
Elastic Deformation ◽  
Coefficient Of Friction ◽  
Internal Diameter ◽  
Tension And Compression ◽  
The Coefficient Of Friction ◽  
Harsh Conditions

Plastic plain bearings are deformed during assembly. According to one of the leading manufacturers of plastic sliding elements, the bushing’s internal diameter may be reduced by up to 2.5%. Moreover, plastic sliding elements are increasingly used in harsh conditions (e.g., under high pressure). However, there are no papers that describe the influence of deformation under compression on the tribological properties of plastics. Specimens made of PTFE, PA6, and PE-HD were deformed while conducting the current research, and this deformation was maintained during cooperation with steel. The results of microhardness, wear, and the coefficient of friction tests were compared to data gathered during tests of non-deformed specimens. During deformation under compression (e ≈ 6%), microhardness lowered by up to 30% (PTFE). A significant reduction of hardness (by up to 15%) was observed when strain was only 2%, and up to this value of strain, there is mainly elastic deformation in the polymer. Changes of the coefficient of friction values were insignificant. In terms of PTFE and PE-HD, during deformation under compression up to e ≈ 6% , the block scar volumes were 20% and 40% larger, respectively, than the non-deformed form of specimens. In terms of PA6, the change in block scar volume was insignificant. It may seem that tension and compression ought to cause totally different effects. However, the comparison of the current results and the results described in the previous paper exposes that these two different processes led to the same effects – reducing hardness and increasing wear. Deformation of plastic sliding components as an effect of assembly appears to be minor; however, it affects polymer microhardness and wear resistance.

An Empirical Approach to Modeling the Friction Coefficient for Wheel-Rail Contact

2009 ◽  
Author(s):  
HyunWook Lee ◽  
Corina Sandu ◽  
Carvel Holton ◽  
Mehdi Ahmadian
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Dry Friction ◽  
Damping Ratio ◽  
Contact Dynamics ◽  
Nonlinear Dependence ◽  
Accurate Estimation ◽  
Highly Nonlinear ◽  
The Coefficient Of Friction ◽  
Wheel Vibration

The coefficient of friction (CoF) is one of the most important parameters for the contact between the wheel and the rail. Accurate estimation or measurement of the CoF has a very important role, both in terms of modeling the train dynamics and in terms of reducing operational costs in the long-term. For ease of implementation, since the nature of the wheel-rail contact dynamics is very complex, the assumption of a constant CoF is still used in most theoretical studies. Nevertheless, experimental work indicates that the CoF depends on dynamic changes in various wheel-rail conditions, like sliding velocity, contact patch shape and size for stick and sliding region, wheel and rail geometry, wheel vibration, rail surface roughness and/or lubrication, etc. In this paper we present the proposed equation to model the nonlinear dry friction coefficient at the wheel-rail contact. The friction coefficient is calculated at the three different values for change in the damping ratio while maintaining all the other conditions the same. As expected, the analysis performed to estimate the dry friction coefficient based on the proposed equation and using NUCARS® simulation results shows that the coefficient of friction has a highly nonlinear dependence on its parameters.

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.

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