scholarly journals The tribological properties of lubricating greases produced on vegetable base and modified of polytetrafluoroethylene

2020 ◽  
Vol 37 (1−2) ◽  
Author(s):  
Rafal Kozdrach
Keyword(s):  
Correlation Function ◽  
Fatigue Life ◽  
Rheological Properties ◽  
Coefficient Of Friction ◽  
Sunflower Oil ◽  
Test Results ◽  
Wear Protection ◽  
The Coefficient Of Friction ◽  
Load Conditions ◽  
Modifying Additive

The article presents the results of research on the influence of polytetrafluoroethylene additive on the tribological and rheological properties of selected lubricant compositions. Based on the obtained test results, it was found that the introduction of a modifying additive to the lubricant structure allows a significant reduction of the coefficient of friction, thus increasing the efficiency of tribological protection of the tribosystem. All lubricating compositions modified with at least 1% polytetrafluoroethylene guarantee effective anti-wear protection under load conditions of the tribosystem. Modification of the tested lubricating compositions with the applied additive affects the increase of indicators characterizing the fatigue life of the examined lubricating greases based on sunflower oil. The introduction of the polytetrafluoroethylene into the structure of the tested lubricants changed the values of the MSD correlation function and the G’ and G’’ modules, which significantly influenced the internal structure of the tested lubricant compositions.

Friction-Instability: A New Design Parameter for Brakes

1971 ◽  
Vol 93 (4) ◽  
pp. 1225-1228 ◽  
Author(s):  
W. L. Starkey ◽  
T. G. Foster ◽  
S. M. Marco
Keyword(s):  
Quality Control ◽  
Coefficient Of Friction ◽  
Design Parameter ◽  
Control Device ◽  
Experimental Facility ◽  
Test Results ◽  
Effective Manner ◽  
The Coefficient Of Friction ◽  
Brake Lining ◽  
The Right

A new design parameter, friction-instability, is defined in this paper. Friction-instability is a variation in the coefficient of friction which may occur at any time during the life of a brake lining. A friction-index is defined which measures this variation. A lining which has a high friction index may tend to cause an automobile to swerve either to the right or to the left. A unique experimental facility is described by means of which the friction-instability characteristics of brake linings can be measured. Test results using this facility are presented and interpreted. The friction-index is proposed as a new parameter which should be taken into consideration when brakes are designed and, developed. This index should be particularly useful as a quality control device to insure that machines which use mass-produced braking systems will perform in a safe and effective manner.

Calculation of Cylindrical Worm Gear Drives of Different Tooth Profiles

1981 ◽  
Vol 103 (1) ◽  
pp. 73-82 ◽  
Author(s):  
H. Winter ◽  
H. Wilkesmann
Keyword(s):  
Coefficient Of Friction ◽  
Theoretical Basis ◽  
Power Loss ◽  
Influence Factor ◽  
Load Capacity ◽  
Worm Gear ◽  
Important Influence ◽  
Test Results ◽  
The Coefficient Of Friction ◽  
Gear Drives

The formulae of classical hydrodynamics are not suitable for the calculation of load capacity and power loss of worm gear drives. Thus a theoretical basis had to be developed for the comparison of different tooth profiles, materials of worm and worm wheel and lubricants. The data obtained were compared with test results. It proved that the coefficient of friction is an important influence factor.

The Data Processing Technique of Metallic Sheet Friction Coefficient Determination

2012 ◽  
Vol 184-185 ◽  
pp. 688-691
Author(s):  
Huan Xue ◽  
Rong Feng Li ◽  
Hong Chuan Zhu
Keyword(s):  
Data Processing ◽  
Coefficient Of Friction ◽  
Normal Pressure ◽  
Processing Technique ◽  
Test Results ◽  
Friction Zone ◽  
Data Processing Method ◽  
The Coefficient Of Friction ◽  
Processing Techniques ◽  
Metallic Sheet

The definition and research background of friction is introduced. The reason of generation of friction is analyzed, the importance of the coefficient of friction test in sheet metal forming field is indicated. The testing principle of coefficient of friction on metallic sheet is presented. The basic data processing method of the test is described. Two important data processing techniques which will obviously effects the test results, including effective friction zone and normal pressure have been carefully studied. The comparison result shows these techniques can effectively enhance the testing stability and precision.

scholarly journals Energy Dissipated in Fatigue and Creep Conditions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4724
Author(s):  
Stanisław Mroziński ◽  
Zbigniew Lis ◽  
Halina Egner
Keyword(s):  
Fatigue Life ◽  
Constant Load ◽  
Test Results ◽  
Fatigue Load ◽  
P91 Steel ◽  
Fatigue Process ◽  
Energy Dissipated ◽  
Load Conditions

The paper presents the results of tests performed on samples made of P91 steel under combined variable and constant load conditions, at temperature T = 600 °C. The analysis of the test results was carried out with the use of the energetic description of the fatigue process. It was shown that the order of occurrence of the fatigue load and creep in the load program influences the fatigue life and the value of the energy cumulated in the sample until fracture.

Comparison of Dry-Film and Zinc-Phosphate Lubricant for Tube Cold Forming

2011 ◽  
Vol 295-297 ◽  
pp. 2362-2365
Author(s):  
Zhi Yan Cheng
Keyword(s):  
Coefficient Of Friction ◽  
Zinc Phosphate ◽  
Test Results ◽  
Tube Surface ◽  
Cold Forming ◽  
Breakdown Time ◽  
Significant Difference ◽  
Potential Applications ◽  
The Coefficient Of Friction ◽  
Dry Film

Dry-film and zinc-phosphate (Zn-P) lubricants were compared for potential applications of dry-film lubricant in tube cold forming processes through the twist compression test. Test results showed that the coefficient of friction (m) had no significant difference between Zn-P soap lube and dry-film lube. The lube coating breakdown time is different between Zn-P soap and dry-film lube. A preliminary industrial trial with dry-film coated tube through the cold drawn over a mandrel showed that the tube surface quality is good and comparable with the Zn-P coated tubes.

TRIBOLOGICAL CHARACTERISTICS OF POLYURETHANES USED FOR THE SOLES OF FOOTWEAR

Tribologia ◽  
2021 ◽  
Vol 294 (6) ◽  
pp. 71-75
Author(s):  
Jacek Przepiórka ◽  
Marian Szczerek ◽  
Marian W. Sułek
Keyword(s):  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Base Material ◽  
Operating Conditions ◽  
Test Results ◽  
Footwear Industry ◽  
Wear And Tear ◽  
Variable Friction ◽  
The Coefficient Of Friction ◽  
Shoe Soles

The inability to take into account the type of base material (floor, pavement, soil), as well as the inability to take into account the variable friction conditions – load, intermediary medium (water, loose abrasive, sand or other soil particles), sliding velocity, and ambient temperature – is a significant limitation the use of friction methods and devices used so far in the footwear industry to precisely anticipate the behavior of the bottom materials in the actual operating conditions of the footwear. These limitations prompted the authors to adapt a tribological tester for this purpose, used in the area of construction and operation of machines and material engineering. A research methodology was developed and, in order to verify it, measurements of the coefficient of friction and wear of polyurethane used for shoe soles in combination with a raw and varnished wooden substrate were carried out. The obtained test results are characterized by diversity, which proves the high research resolution of the developed method. It allows determining the coefficient of friction of associations influencing the slip of the footwear and the wear and tear that determines the length of use of the footwear.

Development of Portable Tester for Measuring Skid Resistance and Its Speed Dependency on Pavement Surfaces

1996 ◽  
Vol 1536 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Kazuo Saito ◽  
Takashi Horiguchi ◽  
Atsushi Kasahara ◽  
Hironari Abe ◽  
John Jewett Henry
Keyword(s):  
Coefficient Of Friction ◽  
International Association ◽  
Constant Load ◽  
Skid Resistance ◽  
Test Results ◽  
Maintenance Program ◽  
Service Period ◽  
Friction Component ◽  
The Coefficient Of Friction

Skid resistance is an important factor in a rational maintenance program for pavement surfaces. Therefore, the skid resistance of a road surface is monitored by maintaining skid resistance inventories; in addition, spot checks are made at high accident sites. The equipment, called the dynamic friction tester (DF tester), is a disc-rotating-type tester that measures the friction force between the surface and three rubber pads attached to the disc. The disc rotates horizontally at a linear speed of about 80 to 20 km/hr under a constant load, so the DF tester can measure the skid resistance at any speed in this range with a single measurement. At the same time, the results provide speed dependency of skid resistance that will be as close as possible to the results obtained by other testing modes. The DF tester can measure on flat as well as rutted surfaces, the depths of which are less than 6 mm. In that case, the coefficient of variation is found to be less than 10 percent. The long-term characteristics of the coefficient of friction were measured by the DF tester, the British pendulum tester and the mini-texture meter. The coefficient of friction increases moderately with the traffic service period (up to 35 weeks) and decreases with increasing speed. The test results showed a significant speed dependency on the coefficient of friction measured by the DF tester although there was a high relationship between the coefficient of friction of the DF tester and the British pendulum number at each point and at each measuring speed. A weak relationship was found between the coefficient of friction and the sensor-measured texture depth values produced by the texture meter. Results of the Permanent International Association of Road Congresses experiment to compare and harmonize texture and skid resistance measurements indicate that the DF tester is capable of reporting the friction component (F60) of the international friction index using the friction coefficient at 60 km/hr.

scholarly journals The Performance of SiO2 and TiO2 Nanoparticles as Lubricant Additives in Sunflower Oil

Lubricants ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Vicente Cortes ◽  
Karen Sanchez ◽  
Ramiro Gonzalez ◽  
Mataz Alcoutlabi ◽  
Javier A. Ortega
Keyword(s):  
Silicon Dioxide ◽  
Tio2 Nanoparticles ◽  
Sunflower Oil ◽  
Parallel Plate ◽  
Lubricant Additives ◽  
Experimental Results ◽  
Wear Protection ◽  
The Coefficient Of Friction ◽  
Conventional Models ◽  
Biodegradable Lubricant

In recent years, there has been growing concern regarding the use of petroleum-based lubricants. This concern has generated interest in readily biodegradable fluids such as vegetable oils. The present work evaluated the rheological and tribological characteristics of sunflower oil modified with silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles as lubricant additives at different concentrations. A parallel plate rheometer was used to evaluate the effects of concentration and shear rate on the shear viscosity, and the experimental data was compared with conventional models. The wear protection and friction characteristics of the oil-formulations were evaluated by conducting block-on-ring sliding tests. Surface analysis-based instruments, including scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and profilometry, were used to characterize the morphology and structure of the worn surfaces. The experimental results showed that the coefficient of friction decreased with the addition of SiO2 and TiO2 nanoparticles by 77.7% and 93.7%, respectively when compared to base sunflower oil. Furthermore, the volume loss was lowered by 74.1% and 70.1%, with the addition of SiO2 and TiO2 nanoparticles, respectively. Based on the experimental results, the authors conclude that modified sunflower oil enhanced with nanoparticles has the potential for use as a good biodegradable lubricant.

scholarly journals STRUCTURE AND PROPERTIES OF THE АК12М2МгН (AlSi12Cu2MgNi) PISTON ALLOY FORMED UNDER THE INFLUENCE OF A COMPLEX MODIFYING ADDITIVE OF FULLERENE-CONTAINING SOOT AND COPPER

2021 ◽  
Vol 2 (55) ◽  
pp. 73-80
Author(s):  
A.I. Komarov ◽  
◽  
D.V. Orda ◽  
D.O. Iskandarova ◽  
◽  
...  
Keyword(s):  
Coefficient Of Friction ◽  
Relative Elongation ◽  
High Wear Resistance ◽  
Simultaneous Increase ◽  
Structure And Properties ◽  
Carbon Particles ◽  
Study Results ◽  
The Coefficient Of Friction ◽  
Tribotechnical Characteristics ◽  
Modifying Additive

The article presents the study results of the complex modification of eutectic silumin АК12М2МгН (AlSi12Cu2MgNi) with additives of fullerene-containing soot (FCS) and copper. It is shown that the effect on the alloy structure is caused by the introduction of carbon nanoparticles into the melt and is manifested in the dispersion of the structural phases and their uniform distribution in the casting volume. At the same time, the use of dispersed copper powder provides wetting of aluminum carbon particles with the melt and additional alloying of the melt. The formation of a dispersed structure leads to an increase in the mechanical and tribotechnical characteristics of the alloy: an increase in the ultimate strength (by 1.3–1.6 times) with a simultaneous increase in the relative elongation by up to 3 times, a significant decrease in the coefficient of friction (by 1.1–1.7 times) and the intensity of wear. The lowest coefficient of friction and high wear resistance are achieved at small fractions of FCS (0.05–0.1 wt.%) and the copper content in the modifier is not more than 0.5 wt.%.

Experimental Study on Friction of Steel Wires of Dynamic Umbilical for Fatigue Life Analysis

2019 ◽  
Author(s):  
Yuanchao Yin ◽  
Qingzhen Lu ◽  
Shanghua Wu ◽  
Jun Yan ◽  
Qianjin Yue ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Coefficient Of Friction ◽  
Fatigue Behavior ◽  
Steel Wire ◽  
Friction Stress ◽  
Steel Wires ◽  
Stress Changes ◽  
The Coefficient Of Friction ◽  
Life Analysis ◽  
Fatigue Life Analysis

Abstract Dynamic umbilicals are widely used in the wet tree development of deep-water field. In the application of dynamic umbilicals, fatigue is a key failure mode which may cause severe economic consequences. The fatigue behavior of dynamic umbilical is complicated by the mechanical properties of the material, the cross-section design and the interaction of different components. Published studies have shown that the interaction friction stress of steel wires is critical for fatigue analysis. Coefficient of friction were used as a constant during the fatigue life analysis. However, the friction stress and the coefficient of friction may change during the wear of the steel wire. This paper presents a new experiment method and device to evaluate the change of the coefficient of friction of steel wire. Different cycles of reciprocating wear were carried out on samples to simulate interaction of the steel wires during the process of fatigue. The samples are pairs of steel wires which were cut on a dynamic umbilical. The interaction stress and friction stress were measured during the test. Micro morphology on the surface of steel wire at the contract zone were measured to investigate the wear of the sample. The test result shows that the coefficient of friction and stress changes during the test. Worn marks were found on the contact zone of the steel wires. The change of the coefficient of friction may affect the accuracy of fatigue life analysis of dynamic umbilical. Conclusions were also presented on the coefficient of friction test and theoretical calculation method to approach a more accurate fatigue life for dynamic umbilical design.

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