Modeling and Data Analysis of the NASA-WSTF Frictional Heating Apparatus: Effects of Test Parameters on Friction Coefficient

2009 ◽  
pp. 172-172-16 ◽  
Author(s):  
S-H Zhu ◽  
JM Stoltzfus ◽  
FJ Benz ◽  
WW Yuen
Keyword(s):  
Data Analysis ◽  
Friction Coefficient ◽  
Frictional Heating ◽  
Test Parameters

Abrasive wear response of Al-Si–SiCp composite: Effect of friction heat and friction coefficient

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Raj Kumar Singh ◽  
Amit Telang ◽  
Satyabrata Das
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Abrasive Wear ◽  
Applied Load ◽  
Frictional Heating ◽  
Matrix Alloy ◽  
Composite Effect ◽  
Friction Heat ◽  
Wear Response ◽  
Abrasive Size

Abstract The effects of friction heat and friction coefficient on the abrasive wear response of Al-7.5Si–SiCp composite against low-cost hypereutectic (Al-17.5Si) alloy were investigated as functions of the abrasive size and applied load in both as-cast and after heat-treatment conditions. Experiments were performed on pin-on-disc apparatus at 38 –80 μm abrasive size, 5 – 20 N applied load, 100 –400 m abrading (sliding) distances and 1 m s–1 constant sliding speed. The frictional heating of as-cast and heat-treated composite was superior compared to the matrix alloy and hypereutectic alloy, whereas the trend reversed for the friction coefficient. The frictional heating and friction coefficient of the materials increased with the abrasive size and applied load in both as-cast and after heat-treatment. The worn surface and wear debris particles were examined by using field emission scanning electron microscopy to understand the wear mechanism.

Tribological and percolation properties of polypropylene/nanodiamond soot composites

2019 ◽  
Vol 28 (6) ◽  
pp. 369-377
Author(s):  
Oleg V Lebedev ◽  
Olga I Bogdanova ◽  
Galina P Goncharuk ◽  
Alexander N Ozerin
Keyword(s):  
Friction Coefficient ◽  
Percolation Threshold ◽  
Mechanical Characteristics ◽  
Testing Procedure ◽  
Test Parameters ◽  
Wear And Friction ◽  
Drastic Increase ◽  
The Relationship ◽  
Disk Testing ◽  
Physical And Mechanical Characteristics

The relationship between surface- and bulk-related physical and mechanical characteristics of polypropylene (PP)-based composites filled with nanodiamond soot (NDS) particles was investigated. The tribological properties of a composite were considered as surface properties. Wear and friction coefficient values were measured using a steel pin-on-composite disk testing procedure under the justified set of test parameters. Loading of NDS particles to the PP matrix resulted in a drastic increase in the composite’s wear resistance. A significant increase in friction coefficient and contact temperature was observed for the composites with NDS content below a certain value assumed to be the percolation threshold for the selected processing method and components used. After the percolation threshold is reached, the friction coefficient decreases sharply and returns to the value characteristic of a filler-free PP. The effects observed were attributed to changes in properties of polymer matrix and composite melt.

scholarly journals Dependency of Rubber Friction on Normal Force or Load: Theory and Experiment

2017 ◽  
Vol 45 (1) ◽  
pp. 25-54 ◽  
Author(s):  
Gaetano Fortunato ◽  
Vincenzo Ciaravola ◽  
Alessandro Furno ◽  
Michele Scaraggi ◽  
Boris Lorenz ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Frictional Heating ◽  
Measured Temperature ◽  
Load Theory ◽  
Time Integral ◽  
Rubber Friction ◽  
Pressure Dependency ◽  
Road Surfaces ◽  
Good Agreement

ABSTRACT In rubber friction studies, it is often observed that the kinetic friction coefficient μ depends on the nominal contact pressure p. We discuss several possible origins of the pressure dependency of μ: (1) saturation of the contact area (and friction force) due to high nominal squeezing pressure; (2) nonlinear viscoelasticity; (3) nonrandomness in the surface topography, in particular the influence of the skewness of the surface roughness profile; (4) adhesion; and (5) frictional heating. We show that in most cases the nonlinearity in the μ(p) relation is mainly due to process (5), frictional heating, that softens the rubber, increases the area of contact, and (in most cases) reduces the viscoelastic contribution to the friction. In fact, because the temperature distribution in the rubber at time t depends on the sliding history (i.e., on the earlier time t′ < t), the friction coefficient at time t will also depend on the sliding history, that is, it is, strictly speaking, a time integral operator. The energy dissipation in the contact regions between solids in sliding contact can result in high local temperatures that may strongly affect the area of real contact and the friction force (and the wear-rate). This is the case for rubber sliding on road surfaces at speeds above 1 mm/s. Previously, we derived equations that described the frictional heating for solids with arbitrary thermal properties. Here, the theory is applied to rubber friction on road surfaces. Numerical results are presented and compared to experimental data. We observe good agreement between the calculated and measured temperature increase.

Investigation on the Effect of Test Parameters on Small Punch Creep Tests by Finite Element Method

2009 ◽  
Vol 631-632 ◽  
pp. 393-398 ◽  
Author(s):  
Jian Ping Wang ◽  
Gang Chen ◽  
Peng Cheng Zhai ◽  
Qing Jie Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Friction Coefficient ◽  
Specimen Thickness ◽  
Regression Equations ◽  
Test Results ◽  
Small Punch ◽  
Test Parameters ◽  
Inner Diameter ◽  
Element Method

The small punch creep (SP-C) test technique is a new method which is applied to evaluate the high temperature creep properties of materials by using miniature specimen. In the present paper, the Finite Element Method (FEM) is employed to simulate the SP-C test in order to investigate the effects of test parameters on testing results of the SP-C test. In this attempt, we perform systematic numerical simulations of SP-C tests by changing friction coefficient, specimen thickness, the diameter of punch ball and the inner diameter of lower die, and discuss the effects of the variation of test parameters on test results in detail. The resulting regression equations for assessing the effects of testing parameters on test results are obtained. It is found that the test results are influenced significantly by the specimen thickness, the diameter of punch ball and the inner diameter of lower die. However, the effects of friction coefficient on the results of the SP-C test can be neglected.

Effect of Surface Profile Structure on Stability of Friction and Wear

2004 ◽  
Author(s):  
A. Titov ◽  
R. Dubrovsky
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Testing Machine ◽  
Surface Profile ◽  
Friction Testing ◽  
Test Parameters ◽  
Texture Parameters ◽  
Wear Friction ◽  
Profile Characteristics

This paper describes the role of surface texture parameters of bodies in contact on friction coefficient and wear rate. Experiments are done on wear friction testing machine that allows dynamically tracking friction coefficient and wear rate of surfaces in contact under heavy-duty boundary lubrication conditions. Experiments based on conforming steel 4340 -bronze SAE 40 friction couple showed the role of profile characteristics of bodies in contact such as skewness and bearing length ratio. Experimental results demonstrated that for surfaces with similar roughness, waviness and profile parameters, a surface with skewness higher than −1.3 invokes instability in test parameters causing fast climb of friction coefficient and increased mass loss.

scholarly journals Effect of Test Parameters on the Friction Behaviour of Anodized Aluminium Alloy

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
M. Guezmil ◽  
W. Bensalah ◽  
A. Khalladi ◽  
K. Elleuch ◽  
M. De-Petris Wery ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Friction Coefficient ◽  
Oxide Layer ◽  
Wear Mechanism ◽  
Optical Emission ◽  
Anodic Oxide ◽  
Tribological Behaviour ◽  
Speed Increase ◽  
Test Parameters ◽  
Pin On Disc

The tribological behaviour of anodic oxide layer formed on Al5754, used in automotive applications, was investigated against test parameters. The friction coefficient under different normal loads, sliding speeds, and oxide thicknesses was studied using a pin on disc tribometer. Results show that the increase of load and sliding speed increase the friction coefficient. The rise of contact pressure and temperature seems to cause changes in wear mechanism. Glow-discharge optical emission spectroscopy (GDOES) was used to investigate the chemical composition of the oxide layer. Morphology and composition of the wear tracks were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). On the basis of these characterization techniques, a wear mechanism was proposed. The observed mechanical properties can be related to the morphology and the chemical composition of the layer.

scholarly journals Parameters that influence microtensile bond testing of adhesive systems

2014 ◽  
Vol 62 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Estevam Carlos de Oliveira LULA ◽  
Taissa Helena Martins LEITE ◽  
Cláudia Maria Coelho ALVES ◽  
Ivone Lima SANTANA ◽  
Ana Maria Lima ALMEIDA ◽  
...  
Keyword(s):  
Data Analysis ◽  
Critical Review ◽  
Search Strategy ◽  
Reliable Data ◽  
Test Results ◽  
Review Of The Literature ◽  
Adhesive Systems ◽  
Analysis Methodology ◽  
Test Parameters ◽  
Microtensile Test

The aim of this study was to provide a critical review of the literature regarding factors that can interfere with microtensile test results for enamel and dentin adhesive systems. Primarily, reports in English, Spanish, or Portuguese that were published between July 1994 and September 2009 and are catalogued in MEDLINE and BBO were used. Additionally, we compiled relevant articles found in the references of these articles and dissertations and theses available in electronic databases of Brazilian universities that examined factors that can influence implementation of the microtensile test at each stage. The search strategy included searching for the following key term groups: microtensile and test; microtensile and assay; microtensile and test and parameters; microtensile and test and factors; microtensile and specimen; microtraccón and especimen. We reviewed 25 selected articles and found that they showed that even after adjustment of test parameters, changes found in the dentin could be responsible for variations observed amongst results. This influence could potentially be reduced by using the cohesive strength value of dentin adjacent to the adhesive interface as a standard for comparison, but more studies are needed to confirm whether such an approach would be reliable. Data analysis methodology should be taken into account when comparing studies.

scholarly journals Tribological Behavior of Polymers and Polymer Composites

2020 ◽  
Author(s):  
Lorena Deleanu ◽  
Mihail Botan ◽  
Constantin Georgescu
Keyword(s):  
Friction Coefficient ◽  
Tribological Behavior ◽  
Glass Beads ◽  
Linear Wear ◽  
Neat Polymer ◽  
Linear Wear Rate ◽  
Test Parameters ◽  
Order Of Magnitude ◽  
Contact Durability

This chapter means to explain the tribological behavior of polymer-based materials, to support a beneficial introducing of those materials in actual applications based on test campaigns and their results. Generally, the designers have to take into consideration a set of tribological parameters, not only one, including friction coefficient, wear, temperature in contact, contact durability related to application. Adding materials in polymers could improve especially wear with more than one order of magnitude, but when harder fillers are added (as glass beads, short fibers, minerals) the friction coefficient is slightly increased as compared to neat polymer. In this chapter, there are presented several research studies done by the authors, from which there is point out the importance of composite formulation based on experimental results. For instance, for PBT sliding on steel there was obtained a friction coefficient between 0.15 and 0.3, but for the composite with PBT + micro glass beads, the value of friction coefficient was greater. Adding a polymer playing the role of a solid lubricant (PTFE) in these composites and also only in PBT, decreased the friction coefficient till a maximum value of 0.25. The wear parameter, linear wear rate of the block (from block-on-ring tester) was reduced from 4.5 μm/(N⋅km) till bellow 1 μm/(N⋅km) for a dry sliding regime of 2.5…5 N, for all tested sliding velocities, for the composite PBT + 10% glass beads +10% PTFE, the most promising composite from this family of materials. This study emphasis the importance of polymer composite recipe and the test parameters. Also there are presented failure mechanisms within the tribolayer of polymer-based materials and their counterparts.

scholarly journals Rapeseed oil additivated with hexagonal boron nitride

2020 ◽  
Vol 12 (2) ◽  
pp. 63-72
Author(s):  
Traian Florian IONESCU ◽  
Adrian-Alin SORCARU ◽  
Dionis GUGLEA ◽  
George Catalin CRISTEA ◽  
Constantin GEORGESCU ◽  
...  
Keyword(s):  
Particle Size ◽  
Friction Coefficient ◽  
Boron Nitride ◽  
Rapeseed Oil ◽  
Mass Concentration ◽  
Hexagonal Boron Nitride ◽  
Average Particle Size ◽  
Average Particle ◽  
Test Parameters ◽  
Tribological Parameters

This paper presents the influence of hexagonal boron nitride (hBN) as additive in refined rapeseed oil in different mass concentration of 0.25%wt, 0.5%wt and 1%wt on the tribological parameters, obtained on a four-ball machine. The test parameters were load: 100 N, 200 N and 300 N and the rotational speed 1000 rpm, 1400 rpm and 1800 rpm, corresponding to the following sliding speed, 0.38 m/s, 0.53 m/s and 0.69 m/s, respectively. The average particle size of hBN is 14 nm. For the tested ranges of the parameters, the additivation of rapeseed oil with hBN does not improve the friction coefficient, but the wear rate of WSD seems to be less sensitive for the more severe regimes when the vegetal oil is additivated.

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