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 Scaling theory of rubber sliding friction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reinhard Hentschke ◽  
Jan Plagge
Keyword(s):  
Experimental Data ◽  
Dimensional Analysis ◽  
Coefficient Of Friction ◽  
Solid Surface ◽  
Viscoelastic Properties ◽  
Sliding Friction ◽  
Simple Expression ◽  
The Other ◽  
Coefficient Of Sliding Friction ◽  
The Coefficient Of Friction

AbstractCurrent theoretical descriptions of rubber or elastomer friction are complex—usually due to extensive mathematical detail describing the topography of the solid surface. In addition, the viscoelastic properties of the elastomer material itself, in particular if the rubber is highly filled, further increase the complexity. On the other hand, experimental coefficients of sliding friction plotted versus sliding speed, temperature or other parameters do not contain much structure, which suggests that a less detailed approach is possible. Here we investigate the coefficient of sliding friction on dry surfaces via scaling and dimensional analysis. We propose that adhesion promotes viscoelastic dissipation by increasing the deformation amplitude at relevant length scales. Finally, a comparatively simple expression for the coefficient of friction is obtained, which allows an intuitive understanding of the underlying physics and fits experimental data for various speeds, temperatures, and pressures.

The Efficiency of Involute Spur Gears

1981 ◽  
Vol 103 (1) ◽  
pp. 160-169 ◽  
Author(s):  
K. F. Martin
Keyword(s):  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Experimental Tests ◽  
Rolling Friction ◽  
Gear Train ◽  
Small Range ◽  
Load Effect ◽  
Coefficient Of Sliding Friction ◽  
The Coefficient Of Friction ◽  
Basic Characteristics

Approximate equations produced by Trachman |15| are used to predict the coefficient of sliding friction between the gear teeth. These equations apply when the lubrication regime is elastohydrodynamic; this is true during many gear contacts. The equations, which require only certain basic characteristics of the lubricant and the gears, are relatively simple and produce values for the coefficient of friction which are acceptable. The use of this coefficient of friction, together with a calculation for the rolling friction force allows the calculation of instantaneous and overall efficiency of the gear train. Contact ratios greater than one are accounted for and the load is assumed to be shared equally between the pairs of teeth. The computed values show that the load torque has a significant effect on both coefficient of friction and efficiency; as the load increases the coefficient of friction increases and the efficiency decreases. The effect of speed does not, over the small range of computations made, have as much significance as load, although it appears that efficiency will probably increase as the speed increases. Comparison of these predicted results with the few experimental tests which are relevant indicates some support, especially for the load effect.

scholarly journals Scaling Theory of Rubber Sliding Friction

2021 ◽  
Author(s):  
Reinhard Hentschke ◽  
Jan Plagge
Keyword(s):  
Experimental Data ◽  
Dimensional Analysis ◽  
Coefficient Of Friction ◽  
Solid Surface ◽  
Viscoelastic Properties ◽  
Sliding Friction ◽  
Simple Expression ◽  
The Other ◽  
Coefficient Of Sliding Friction ◽  
The Coefficient Of Friction

Abstract Current theoretical descriptions of rubber or elastomer friction are complex-usually due to extensive mathematical detail describing the topography of the solid surface. In addition, the viscoelastic properties of the elastomer material itself, in particular if the rubber is highly filled, further increase the complexity. On the other hand, experimental coefficients of sliding friction plotted versus sliding speed, temperature or other parameters do not contain much structure, which suggests that a less detailed approach is possible. Here we investigate the coefficient of sliding friction on dry surfaces via scaling and dimensional analysis. We propose that adhesion promotes viscoelastic dissipation by increasing deformation amplitude at relevant length scales. Finally, a comparatively simple expression for the coefficient of friction is obtained, which allows an intuitive understanding of the underlying physics and fits experimental data for various speeds, temperatures and pressures.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

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.

Tribological Properties of Polyoxymethylene Composites Against Aluminum

2003 ◽  
Vol 125 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Masaya Kurokawa ◽  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Susumu Nagai
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Surface ◽  
Surface Hardness ◽  
Disk Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
The Other ◽  
The Coefficient Of Friction

Tribological properties of several kinds of polyoxymethylene (POM) composites were evaluated for the purpose of developing a polymeric tribomaterial especially suited for mating with aluminum parts having low surface hardness. POM composites containing small amounts of silicon carbide (SiC), POM/SiC; those containing a small amount of calcium octacosanonoate besides SiC, POM/SiC/Ca-OCA; and the one blended with 24 wt % of polytetrafluoroethylene, POM/PTFE(24); were injection-molded into pin specimens and their tribological properties were tested by means of a pin-on-disk type wear apparatus using an aluminum (A5056) mating disk in comparison with a 303 stainless steel (SUS303) disk. Evaluation was focused on observation of the sliding surfaces of the pin specimens and the mating disks by a scanning electron microscope and an optical microscope together with the measurement of surface roughness. In the case of mating against a SUS303 disk having high surface hardness, all pin specimens did not roughen the disk surfaces even after long time of rubbing. Only POM/PTFE(24) composite obviously made a transfer film on the disk surface, while the other composites made an extremely thin one on it. POM/SiC(0.1)/Ca-OCA(1) composite, containing SiC 0.1 wt. % and Ca-OCA 1 wt. %, was found to show the lowest coefficient of friction and the lowest wear rate forming extremely thin transfer film on the mating disk. On the other hand, against an A5056 disk which has lower surface hardness than that of SUS303 disk, unfilled POM and POM composites except POM/SiC(0.1)/Ca-OCA(1) composite roughened the disk surfaces. However, the sliding surface of the A5056 disk rubbed with POM/SiC(0.1)/Ca-OCA(1) composite was significantly smoother and that of the pin specimen was also quite smooth in comparison with other pin specimens. Further, when each POM composite was rubbed against the A5056 disk, formation of transfer film was not obvious on the disk surfaces. For POM/SiC(0.1)/Ca-OCA(1) composite, the wear rate was the lowest of all POM composites, and the coefficient of friction was as low level as 60 percent of that of unfilled POM, but slightly higher than that of POM/PTFE(24) composite. For POM/SiC(0.1)/Ca-OCA(1) composite, the nucleating effect of SiC and Ca-OCA, which accelerated the crystallization of POM during its injection molding to form a matrix containing fine spherulites, must have resulted in increasing the toughness of the matrix and lowering the wear rate. Also, the lubricant effect of Ca-OCA should have lowered the coefficient of friction of the same matrix for rubbing against aluminum mating disk. POM/SiC(0.1)/Ca-OCA(1) composite was concluded as an excellent tribomaterial for mating with aluminum parts.

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.

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.

Study of Metal Friction Materials Using Hot Press

2013 ◽  
Vol 750-752 ◽  
pp. 2084-2087
Author(s):  
Shenq Yih Luo ◽  
Can Yu Bai
Keyword(s):  
Coefficient Of Friction ◽  
Wear Mechanisms ◽  
Bending Strength ◽  
Copper Matrix ◽  
Friction Material ◽  
The Other ◽  
Hot Press ◽  
Friction Materials ◽  
The Coefficient Of Friction ◽  
Metal Friction

The metal friction materials of copper matrix with and without resin using hot press were investigated to study their hardness, porosities, bending strengths, microstructures, coefficient of frictions, and wear mechanisms. The experiment results show that the hardness and bending strength of the friction materials with increase of amount of copper increase, but the porosity decreases. The resulting coefficient of frictions show more stable and their values are about 0.5~0.6. In addition, the wear mechanism of friction material shows mainly grit abrasive and adhesion, which cause the coefficient of friction to become stable. On the other hand, when the copper matrix containing resin is used, the resulting porosity of friction materials becomes higher and the bending strength decreases. This shows that the wear mechanisms of grit abrasive, roughness, and adhesion cause the coefficient of friction to produce a higher value.

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