Measurement of Tribological Parameters

2014 ◽  
Vol 875-877 ◽  
pp. 496-499 ◽  
Author(s):  
Eva Labašová ◽  
Rastislav Ďuriš
Keyword(s):  
Coefficient Of Friction ◽  
Test Equipment ◽  
Tribological Characteristics ◽  
Sliding Speed ◽  
Sliding Joint ◽  
The Coefficient Of Friction ◽  
Run Up ◽  
Tribological Parameters

The contribution deals with measurement of the coefficient of friction in the sliding joint. Rotanional sliding pair, which was tested, is described in this paper. Their tribological characteristics were measured by test equipment Tribotestor`89. The value of the coefficient of friction for the bushings from brass, aluminium and polyamide for chosen load (the sliding speed, loading, duration) are analysed in the paper. The largest decrease in the size of the coefficient of friction was recorded for bushings from aluminium, its value have decreased by 87.5% during the run up. Decrease of the coefficient of friction was recorded about 82% for bushings from brass and about 72% for bushings from polyamide. Run up lasted 10 minutes in all tests.

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.

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.

The Dependence of the Friction Coefficient on the Size and Course of Sliding Speed

2014 ◽  
Vol 693 ◽  
pp. 305-310 ◽  
Author(s):  
Eva Labašová
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
Testing Machine ◽  
Current Component ◽  
Sliding Speed ◽  
Rectangular Shape ◽  
Coefficient Increase ◽  
The Coefficient Of Friction ◽  
Ring Method ◽  
Run Up

The coefficient of friction for the bronze material (CuZn25Al6) with insert graphite beds and other bronze material (CuSn12) are investigated in this paper. Friction coefficient was investigated experimentally by the testing machine Tribotestor`89 which uses the principle of the ring on ring method. The external fixed bushing was exposed to the normal load of the same size in all tests. Process of load was increased from level 50 N to 600 N during run up 300 s, after the run up the appropriate level of load was held. The internal bushing performed a rotational movement with constant sliding speed. The value of sliding speed was changed individually for every sample (v = 0.2 (0.3, 0.4) m.s-1). The forth test had a rectangular shape of sliding speed with direct current component 0.3 m.s-1 and the amplitude 0.1 m.s-1 period 300 s, the whole test took 2100 s. The obtained results reveal that friction coefficient increase with the increase of sliding speed.

scholarly journals The Effect of Elemental Composition and Nanostructure of Multilayer Composite Coatings on Their Tribological Properties at Elevated Temperatures

2020 ◽  
Author(s):  
Alexey Vereschaka ◽  
Sergey Grigoriev ◽  
Vladimir Tabakov ◽  
Mars Migranov ◽  
Nikolay Sitnikov ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Elevated Temperatures ◽  
Composite Coatings ◽  
Multilayer Composite ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Tribological Parameters ◽  
Adhesion Component

The chapter discusses the tribological properties of samples with multilayer composite nanostructured Ti-TiN-(Ti,Cr,Al,Si)N, Zr-ZrN-(Nb,Zr,Cr,Al)N, and Zr-ZrN-(Zr,Al,Si)N coatings, as well as Ti-TiN-(Ti,Al,Cr)N, with different values of the nanolayer period λ. The relationship between tribological parameters, a temperature varying within a range of 20–1000°C, and λ was investigated. The studies have found that the adhesion component of the coefficient of friction (COF) varies nonlinearly with a pronounced extremum depending on temperature. The value of λ has a noticeable influence on the tribological properties of the coatings, and the nature of the mentioned influence depends on temperature. The tests found that for the coatings with all studied values of λ, an increase in temperature first caused an increase and then a decrease in COF.

Study on the effects of nano-aluminum-oxide particulates on mechanical and tribological characteristics of chopped carbon fiber reinforced epoxy composites

2015 ◽  
Vol 231 (4) ◽  
pp. 403-422 ◽  
Author(s):  
Kali Dass ◽  
SR Chauhan ◽  
Bharti Gaur
Keyword(s):  
Carbon Fiber ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Epoxy Composites ◽  
Specific Wear Rate ◽  
Tribological Characteristics ◽  
X Ray ◽  
The Coefficient Of Friction ◽  
Mechanical And Tribological Characteristics

An experimental study has been carried out to investigate the mechanical and tribological characteristics of chopped carbon fiber (CCF) reinforced epoxy composites filled with nano-Al2O3 particulates, as a function of fiber and filler contents. The experiments were conducted using a pin-on-disc wear test apparatus under dry sliding conditions. The coefficient of friction and specific wear rate of these composites was determined as a function of applied normal load, sliding velocity, sliding distance, and reinforcement content. The tensile, flexural, and compression strengths of ortho cresol novalac epoxy and chopped carbon fiber (OCNE/CCF) filled composites are found to be within the ranges of 48–58.54 MPa, 115–156.56 MPa, and 48–61.15 MPa. Whereas the tensile, flexural, and compression strengths of OCNE/CCF/Al2O3-filled composites are found to be within the ranges of 96–110 MPa, 176–204.66 MPa, and 72–85.65 MPa, respectively. It has been observed that the coefficient of friction decreases and specific wear rate increases with increase in the applied normal loads. Further increases in the fiber (6 wt%) and particle (3 wt%) contents in the epoxy matrix resulted in a decrease of both the mechanical and tribological properties, but remains above that of the CCF reinforced epoxy composites. The worn surfaces of composites were examined with scanning electron microscopy equipped with energy dispersion X-ray analyzer and X-ray diffraction analysis technique to investigate the wear mechanisms.

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.

Friction of a Rubber Wedge Sliding on Glass

1991 ◽  
Vol 64 (1) ◽  
pp. 108-117 ◽  
Author(s):  
C. W. Extrand ◽  
A. N. Gent ◽  
S. Y. Kaang
Keyword(s):  
Coefficient Of Friction ◽  
Applied Load ◽  
Unit Length ◽  
Sliding Speed ◽  
Normal Loading ◽  
Contact Width ◽  
Wide Range ◽  
The Coefficient Of Friction ◽  
Apparent Coefficient Of Friction ◽  
Pressure Independent

Abstract The contact width, and hence contact area, for an elastic wedge pressed against a rigid flat surface appears to be proportional to the applied load per unit length. For a particular rubber sample, the reciprocal of the constant of proportionality, i.e., the mean normal pressure, was 130 kPa, i.e., about 7% of the tensile modulus E of the material. It was also independent of sliding speed over the range examined. Thus, a sharp wedge gave a relatively high loading pressure, independent of the applied load. As a result, the coefficient of friction was also independent of applied load over a wide range. The coefficient of friction was measured for a wedge of an unfilled natural rubber vulcanizate over wide ranges of sliding speed (50 µm/s to 100 mm/s) and test temperature (3°C to 63°C). It was found to increase with sliding speed and decrease with temperature over these ranges. The results at different temperatures were superposable using the WLF rate-temperature equivalence to create a master curve of friction vs. reduced sliding speed, rising from a value of about 1.5 at high temperatures and low speeds to about 5 at low temperatures and high speeds. Chlorination of a thin surface region reduced the coefficient of friction and its dependence on speed and temperature. It then became similar to that typically found for thermoplastics, 0.4 to 0.7. The geometry of sliding a flexible strip against a rigid curved surface caused high values of the apparent coefficient of friction to be obtained at relatively small departures from normal loading. In an extreme case, frictional seizure was observed when a high-friction sample contacted the glass surface at an angle of about 15° to the direction of loading. The apparent coefficient of friction then became indefinitely large. This same phenomenon of abnormally large frictional effects would be expected to occur in the case of conventional windshield-wiper blades, sliding over curved glass windshields.

scholarly journals RESEARCH OF WORKING BENEFITS OF BEARINGS APPLICATION OF MATHEMATICAL METHOD

2021 ◽  
Vol 08 (04) ◽  
pp. 95-98
Author(s):  
Sevinc Abasova Sevinc Abasova
Keyword(s):  
Coefficient Of Friction ◽  
Thermoplastic Elastomer ◽  
Operating Parameters ◽  
Specific Load ◽  
Sliding Speed ◽  
Friction Units ◽  
Joint Influence ◽  
The Coefficient Of Friction ◽  
Heavy Loads ◽  
Main Operating

It is known that the service life of oilfield machines and mechanisms is to a certain extent determined by the operability of friction units, the operation of which, as a rule, occurs under severe conditions (heavy loads, abrasive aqueous medium, etc.). It is also known that the determining parameters in the units of machines and mechanisms (lubricated with water) with polymer elements are specific load, sliding speed and relative clearance. In the field, these factors affect the coefficient of friction together, therefore, the study of their influence [µ = f (p, ʋ, ψ)] on the coefficient of friction is possible only with the use of mathematical modeling. We have studied the nature of the joint influence of the main operating parameters on the performance of the ison thermoplastic elastomer plain bearings. Keywords: Operation, polymer elements, field conditions, bearings, sliding speed.

Paper 19: Unlubricated Sliding at High Speeds between Copper and Steel Surfaces

1966 ◽  
Vol 181 (15) ◽  
pp. 25-30 ◽  
Author(s):  
M. J. Kadhim ◽  
S. W. E. Earles
Keyword(s):  
Oxide Layer ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Sliding Speed ◽  
Wear Rates ◽  
High Speeds ◽  
Before And After ◽  
The Coefficient Of Friction ◽  
Steel Disc ◽  
Steel Surfaces

Experiments are described in which stationary copper specimens are rubbed in a normal atmosphere against a rotating S62 steel disc under normal loads up to 4·5 lbf. The coefficient of friction is measured at sliding speeds of 93, 220, 328, and 490 ft/s using ⅛-in diameter specimens. Except at the lowest speed a gradual buildup of a continuous copper oxide layer on the disc track is observed with increasing normal load together with a corresponding decrease in the coefficient of friction. Having established an oxide layer on the track the coefficient of friction observed is low for all normal loads. The coefficient of friction is shown to decrease with normal load N and sliding speed U, to be a function of N1/2 U, and to depend on the state of the disc surface. Wear of -in diameter specimens is measured by weighing before and after a test. The wear rate is shown to decrease with sliding speed and increase with load, and for speeds of 220 and 328 ft/s to be a function of N/U. The wear rates measured at 93 ft/s are the same function of N/U for low values of N/U.

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