Statistical Analysis of Kinetic Friction Coefficient for Dry Sliding Plain Bearing on Shaft Test of Polytetrafluoroethylene

Author(s):  
João Luiz do Vale ◽  
Carlos Henrique da Silva
2010 ◽  
Vol 44-47 ◽  
pp. 1923-1927 ◽  
Author(s):  
Xian Jie Meng

A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the stability of vibration system at the equilibrium points is analyzed using the nonlinear dynamics theory. Finally the numerical method is taken to study the impacts of friction coefficient on brake groan. The calculation result shows that with the increase of kinetic friction coefficient /or the decrease of difference value between static friction coefficient and kinetic friction coefficient can prevent or restrain self-excited vibration from happening.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Pranav Dev Srivyas ◽  
M.S. Charoo

Advanced composites are the materials of the new generation. Hence, the focus of the study is to determine the tribological properties of the eutectic Al-Si alloy reinforced with (2, 4, 6, 8, and10 wt. %) of n-Al2O3 against chrome-plated steel ball under dry sliding conditions. The novelty of this work is the fabrication of the composite sample with this elemental composition, which is not done before. Spark plasma sintering (SPS) nonconventional fabrication method is used to fabricate advanced composite samples. Friction coefficient (COF) and wear rate of the composite samples were studied under high load, varying from 50 N to 300 N, using the ball-on-disc tribometer configuration, with other parameters such as stroke, frequency, sliding distance, and sliding velocity remaining constant at 2 mm, 30 Hz, 120 meter, and 0.120 m/s, respectively. Reduction in wear volume for the advanced composite was reported in the range 15.45–44.58% compared to the base alloy (eutectic Al-Si alloy). An increase in friction coefficient was reported in the range 28.80–35.65% compared to the base matrix alloy material. It was also reported that the wear rate increases and the friction coefficient of the composite sample decreases with an increase in load for the tribo-pair. It was observed that an increase in the wt. % of reinforcement influences the friction and wear behavior of the composite. Wear mechanism at high load was characterized by plastic deformation, adhesion, delamination, and abrasion wear. For pre- and postcharacterization of surface and worn tracks, scanning electron microscopy (SEM) electron dispersion spectroscopy (EDS), 3D surface profilometer, and optical microscopy were used. This work aimed to investigate the influence of load on the tribological properties of Al-Si eutectic reinforced n-Al2O3 under dry sliding conditions. Its main objective was to provide a new contribution to the tribological behavior of these composites fabricated using the nonconventional spark plasma sintering method.


Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1862 ◽  
Author(s):  
Luanxia Chen ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Qinghua Song ◽  
Yi Wan ◽  
...  

Eutectic aluminum-silicon alloys present high frictional coefficient and a high wear rate due to the low hardness under sliding friction conditions. In this paper, the eutectic aluminum-silicon alloy was textured firstly by micro-milling operations. Then, the micro-textured specimen was subjected to anodizing to fabricate alumina films. The surface topography, surface roughness, and bearing area ratio of micro-textured and anodizing micro-textured specimens were measured and characterized. For the anodizing micro-textured specimens, the surface roughness and superficial hardness increase compared with those for micro-textured ones. Tribological tests indicate that anodizing micro-textured samples present lower friction coefficient of 0.37 than that of flat samples of 0.43 under dry sliding conditions. However, they exhibit higher friction coefficient at 0.16 than that of flat samples of 0.13 under oil-lubricated conditions. The difference between the friction coefficient of anodizing micro-textured and flat samples under dry and oil-lubricated conditions is ascribed to the influence mechanism of surface roughness, bearing area ratio curves, and its relative parameters on the tribological performance of testing samples. The dry sliding friction coefficient has a positive correlation with bearing area ratio curves, while they present negative correlation with bearing area ratio curves under oil-lubricated conditions. The synergy method treated with micro-milling and anodizing provides an effective approach to enhance the dry sliding friction property of eutectic aluminum-silicon alloys.


2011 ◽  
Vol 314-316 ◽  
pp. 137-142
Author(s):  
Bin Cai ◽  
Ye Fa Tan ◽  
Hui Yong Ji ◽  
Xiao Long Wang ◽  
Long He ◽  
...  

In order to reduce friction coefficient of the Ni-base alloy coating and further improve its wear resistance, the graphite/TiC/Ni-base alloy composite coating was prepared on the surface of 45 carbon steel by plasma spray. Effects of loads, friction counterparts and lubricants on tribological properties of the coating were investigated. The results show that friction coefficient of the composite coating is reduced by 33% than that of the Ni-base alloy coating when worn against GCr15. Wear losses of the composite coating are less than those of the Ni-base alloy coating at all loads of 6N, 8N, 10N and 12N. Worn against Si3N4, friction coefficient of the composite coating is 13% less than that worn against GCr15, but its wear loss is 2.9 times of that worn against GCr15. Wear mechanism of the composite coating is micro cutting and brittle fraction when worn against Si3N4. Under lubrication of NaCl solution, friction coefficient of the composite coating is almost the same as that under dry sliding, wear loss is increased by 1.6 times. Stress corrosion and wedging effects of the NaCl solution are main wear mechanisms of the composite coating.


2016 ◽  
Vol 35 (5) ◽  
pp. 487-492
Author(s):  
Ahmet Karaaslan ◽  
Alptekin Kısasöz ◽  
Ş. Hakan Atapek ◽  
Kerem Altuğ Güler

AbstractThe wear behavior of cast A7075 and A7075/SAF 2205 composite material fabricated by vacuum-assisted investment flask casting was investigated under dry sliding condition. The wear tests were carried out using a “ball-on-disc” type tribometer. In the wear tests, 100Cr6 and ZrO2 balls were used as counterparts and the load, total distance and rotating speed were selected as 10 N, 100 m and 100 rpm, respectively. The results were evaluated using the friction coefficient–distance diagram, weight loss and wear rate. All worn surfaces were examined by scanning electron microscope and wear characteristics of the materials were discussed as a function of the microstructural features. It was concluded that composite material had lower friction coefficient, less weight loss and slower wear rate than that of cast material.


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