Calculations of the coefficient of friction under elastic contact conditions

1969 ◽  
Vol 4 (2) ◽  
pp. 149-152
Author(s):  
N. M. Mikhin
Keyword(s):  
Coefficient Of Friction ◽  
Elastic Contact ◽  
Contact Conditions ◽  
The Coefficient Of Friction

EXPERIMENTAL STUDY OF THE ROLLING–SLIDING CONTACT CONDITIONS IN A PA66/STEEL GEAR USING TWIN-DISC TEST RIG: FRICTION AND WEAR ANALYSIS

2015 ◽  
Vol 22 (06) ◽  
pp. 1550074
Author(s):  
MEFTAH MBAREK ◽  
SADOK RHAIEM ◽  
MOHAMED KHARRAT ◽  
MAHER DAMMAK
Keyword(s):  
Coefficient Of Friction ◽  
Angular Speed ◽  
Linear Increase ◽  
Contact Temperature ◽  
Test Rig ◽  
Contact Conditions ◽  
Slip Ratio ◽  
The Coefficient Of Friction ◽  
Adhesive Interactions ◽  
Different Diameters

This study investigates the effects of sliding ratio on the tribological response of the contact between the teeth of a metal/polymer gear in the regions close to the pitch point. For this purpose, a new twin-disc test rig was developed on the basis of two discs of different diameters rotating one above the other at the same angular speed. Two different materials were used: non-alloyed structural steel (C45) and polyamide (PA66). The effect of the slip ratio (4%, 12%, 20% and 28%) was studied at a constant pressure of 34 MPa and a constant angular speed of 300 rpm. In addition, the contact conditions were controlled with measurements of the two discs surface temperatures. The results indicate that the wear and the friction are closely related to the contact temperature generated by the sliding phenomenon. At low slip ratio (4% and 12%), the coefficient of friction and the temperature are characterized by a quasi-linear increase with time, and the wear increases slowly. At higher slip ratio (20% and 28%), the coefficient of friction and the temperature presents a steady state, and the wear increases dramatically. During the test, a film of transferred PA66 is formed on the steel surface causing the development of adhesive interactions between the contacting discs which increase the friction coefficient and the contact temperature. The high thermal conductivity of steel as compared to that of the polymer can reduce enormously the contact temperature generated by the sliding process.

scholarly journals The Tribological Adaptability for Ventral Scales of Dinodon rufozonatum in Dry/Wet/Rough Environments

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Song Hu ◽  
Ge Shi ◽  
Qinggang Guo ◽  
Long Zheng ◽  
Luquan Ren ◽  
...  
Keyword(s):  
Coefficient Of Friction ◽  
Water Lubrication ◽  
Substrate Roughness ◽  
Contact Conditions ◽  
Frictional Performance ◽  
The Coefficient Of Friction ◽  
Dry Conditions ◽  
Multiple Environments ◽  
Lubrication Conditions

The ventral scales of Dinodon rufozonatum were investigated to understand the outstanding tribological adaptability in various environments. The coefficient of friction (COF) of ventral scales was measured and changed with the contact conditions. It was discovered that the COF of scales under water-lubrication conditions (WLC) was larger than that under dry conditions (DC). More interestingly, the COF increased first and then decreased as the substrate roughness reduced. The abrasion marks on scales were then observed. The results indicated that the scales in DC wore more gently than that in WLC. Moreover, the degree of wear reduced with the decrease of substrate roughness. The frictional performance of ventral scales enabled the snakes to move more efficiently, quickly, and flexibly in multiple environments.

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 Tribological Aspects, Optimization and Analysis of Cu-B-CrC Composites Fabricated by Powder Metallurgy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4217
Author(s):  
Üsame Ali Usca ◽  
Mahir Uzun ◽  
Mustafa Kuntoğlu ◽  
Serhat Şap ◽  
Khaled Giasin ◽  
...  
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Applied Load ◽  
Practical Significance ◽  
Tribological Characteristics ◽  
M 10 ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Four Levels

Tribological properties of engineering components are a key issue due to their effect on the operational performance factors such as wear, surface characteristics, service life and in situ behavior. Thus, for better component quality, process parameters have major importance, especially for metal matrix composites (MMCs), which are a special class of materials used in a wide range of engineering applications including but not limited to structural, automotive and aeronautics. This paper deals with the tribological behavior of Cu-B-CrC composites (Cu-main matrix, B-CrC-reinforcement by 0, 2.5, 5 and 7.5 wt.%). The tribological characteristics investigated in this study are the coefficient of friction, wear rate and weight loss. For this purpose, four levels of sliding distance (1000, 1500, 2000 and 2500 m) and four levels of applied load (10, 15, 20 and 25 N) were used. In addition, two levels of sliding velocity (1 and 1.5 m/s), two levels of sintering time (1 and 2 h) and two sintering temperatures (1000 and 1050 °C) were used. Taguchi’s L16 orthogonal array was used to statistically analyze the aforementioned input parameters and to determine their best levels which give the desired values for the analyzed tribological characteristics. The results were analyzed by statistical analysis, optimization and 3D surface plots. Accordingly, it was determined that the most effective factor for wear rate, weight loss and friction coefficients is the contribution rate. According to signal-to-noise ratios, optimum solutions can be sorted as: the highest levels of parameters except for applied load and reinforcement ratio (2500 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 0 wt.%) for wear rate, certain levels of all parameters (1000 m, 10 N, 1.5 m/s, 2 h, 1050 °C and 2.5 wt.%) for weight loss and 1000 m, 15 N, 1 m/s, 1 h, 1000 °C and 0 wt.% for the coefficient of friction. The comprehensive analysis of findings has practical significance and provides valuable information for a composite material from the production phase to the actual working conditions.

scholarly journals Influence of Beam Power on Young’s Modulus and Friction Coefficient of Ti–Ta Alloys Formed by Electron-Beam Surface Alloying

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1246
Author(s):  
Stefan Valkov ◽  
Dimitar Dechev ◽  
Nikolay Ivanov ◽  
Ruslan Bezdushnyi ◽  
Maria Ormanova ◽  
...  
Keyword(s):  
Electron Beam ◽  
Young’S Modulus ◽  
Coefficient Of Friction ◽  
Young's Modulus ◽  
Beam Power ◽  
Surface Alloying ◽  
Surface Alloys ◽  
X Ray ◽  
The Coefficient Of Friction ◽  
Beam Surface

In this study, we present the results of Young’s modulus and coefficient of friction (COF) of Ti–Ta surface alloys formed by electron-beam surface alloying by a scanning electron beam. Ta films were deposited on the top of Ti substrates, and the specimens were then electron-beam surface alloyed, where the beam power was varied from 750 to 1750 W. The structure of the samples was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Young’s modulus was studied by a nanoindentation test. The coefficient of friction was studied by a micromechanical wear experiment. It was found that at 750 W, the Ta film remained undissolved on the top of the Ti, and no alloyed zone was observed. By an increase in the beam power to 1250 and 1750 W, a distinguished alloyed zone is formed, where it is much thicker in the case of 1750 W. The structure of the obtained surface alloys is in the form of double-phase α’and β. In both surface alloys formed by a beam power of 1250 and 1750 W, respectively, Young’s modulus decreases about two times due to different reasons: in the case of alloying by 1250 W, the observed drop is attributed to the larger amount of the β phase, while at 1750 W is it due to the weaker binding forces between the atoms. The results obtained for the COF show that the formation of the Ti–Ta surface alloy on the top of Ti substrate leads to a decrease in the coefficient of friction, where the effect is more pronounced in the case of the formation of Ti–Ta surface alloys by a beam power of 1250 W.

Reducing the Coefficient of Friction for Fast-Absorbing Gut Suture

2009 ◽  
Vol 35 (12) ◽  
pp. 2004 ◽  
Author(s):  
Jonathan Lee Bingham ◽  
Mariah R. Brown ◽  
Julian Ramsey Mellette
Keyword(s):  
Coefficient Of Friction ◽  
The Coefficient Of Friction

First Paper: Effect of Under-Lip Temperature on the Lubrication of Rotary Shaft Garter Spring Seals

1966 ◽  
Vol 181 (1) ◽  
pp. 185-190 ◽  
Author(s):  
D. J. Lines ◽  
J. M. Lawrie ◽  
J. P. O'Donoghue
Keyword(s):  
Coefficient Of Friction ◽  
Operating Temperature ◽  
Lubrication Theory ◽  
Fluid Film ◽  
Hydrodynamic Parameter ◽  
Accurate Knowledge ◽  
The Coefficient Of Friction ◽  
Surface Thermocouple ◽  
Sealing Mechanism ◽  
Film Lubrication

Although rotary shaft garter spring seals are widely used throughout industry, very little is known about the sealing mechanism of the lip-shaft interface. It is now generally accepted that some sort of fluid film separates the lip and the shaft. Previous workers have also postulated a relationship between the coefficient of friction and a non-dimensional hydrodynamic parameter, as in standard lubrication theory. This present paper clarifies this relationship, and shows that seals can also operate over the mixed friction, as well as the full film lubrication region. The results were obtained by accurate knowledge of the operating temperature under the sealing lip. Two types of surface thermocouple were developed to do this and these are described in full.

The Effect of Nanoparticle Functionalization on Lubrication Performance of Nanofluids Dispersing Silica Nanoparticles in an Ionic Liquid

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Cengiz Yegin ◽  
Wei Lu ◽  
Bassem Kheireddin ◽  
Ming Zhang ◽  
Peng Li ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Coefficient Of Friction ◽  
Shear Thinning ◽  
Antiwear Additives ◽  
Functionalized Silica ◽  
Low Concentrations ◽  
Lubrication Performance ◽  
The Coefficient Of Friction ◽  
High Concentrations ◽  
Newtonian Behavior

Recently, ionic liquids (ILs) have received an increasing attention as lubricants owing to their intriguing properties such as tunable viscosity, high thermal stability, low emissions, nonflammability, and corrosion resistance. In this work, we investigate how the incorporation of octadecyltrichlorosilane (OTS) functionalized silica nanoparticles (NPs) in 1-butyl-3-methylimidazolium (trifluoromethysulfony)imide influences the tribological properties and rheological properties of IL under boundary lubrication and elastohydrodynamic conditions, respectively. It was found that the coefficient of friction was depended on the concentration of NPs in IL with a concave upward functional trend with a minimum at 0.05 wt.% for bare silica NPs and at 0.10 wt.% for OTS-functionalized silica NPs. For steel–steel sliding contact, the presence of functionalized NPs in IL at the optimum concentration decreased the coefficient of friction by 37% compared to IL and 17% compared to IL with bare silica NPs. While IL with bare NPs demonstrated a shear thinning behavior for all concentrations, IL with functionalized NPs showed a Newtonian behavior at low concentrations and shear thinning behavior at high concentrations. Overall, this study provides new insights into the antifriction and antiwear additives for lubrication systems involving ILs.

Paper 16: Friction in Wet Clutches

1967 ◽  
Vol 182 (14) ◽  
pp. 132-138 ◽  
Author(s):  
E. M. Evans ◽  
J. Whittle
Keyword(s):  
Coefficient Of Friction ◽  
Power Transmission ◽  
Sliding Speed ◽  
Friction Materials ◽  
Friction Characteristics ◽  
Sliding Surfaces ◽  
Base Oils ◽  
Wet Friction ◽  
Friction Clutch ◽  
The Coefficient Of Friction

This paper is intended to demonstrate that designers of wet clutches for power transmission can obtain the optimum friction characteristics for specific applications by considering the interaction between friction materials and lubricants. A friction clutch plate rig is described and the friction results obtained are presented. It is shown that a wide variation of coefficients of friction and frictional characteristics in wet friction clutches can be obtained by changing the oils and friction materials. In particular the coefficient of friction is dependent upon (1) the oil, (2) the materials of the sliding surfaces, (3) sliding speed, and (4) temperature. It is also shown that the coefficient of friction is affected by ( a) refining treatment given to the oil, ( b) different base oils, and ( c) additives.

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