The Size of the Friction Coefficient of the Sliding Pair Depending on the Lubricant Used

2018 ◽  
Vol 919 ◽  
pp. 327-334
Author(s):  
Eva Labašová ◽  
Vladimír Labaš
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Normal Load ◽  
Test Machine ◽  
Simple Test ◽  
Experimental Equipment ◽  
Sliding Velocity ◽  
Characteristic Parameters ◽  
Input Parameters ◽  
Load Conditions

Tribometry Methods are Focused on the Research of Tribological Processes. these Method Also Include Model Tests on Experimental Equipment, which Operate in Exactly-Defined Mode. Input Parameters of Tests are Transparent and Easy to Maintain Constant. Outputs Variables, which are Recorded, Represent Characteristic Parameters of Tribological Processes. Tests are Carried out on Simple Test Samples. the Aim of these Methods is to Numerically Express the Magnitude of Friction Force, Friction Moment, Respectively Determinate the Friction Coefficient. the Contribution is Focused on Determining the Friction Coefficient for Brass and Steel Test Samples. the Measurements were Realized on a Test Machine Tribotestor M`89. Size of the Sliding Velocity and Size of the Loading Force were Entered to the Tests as Input Parameters. Two Types of Oil were Used in the Experiments: Castrol Manual EP 80W and Madit PP90. the Results Obtained Show that the Friction Coefficient Value Decreases with the Increasing Normal Load for both Materials and Also for both Lubricants. Smaller Friction Coefficient Values were Achieved Using Lubricant Castrol Manual EP 80W for both Materials. the Average Values of the Friction Coefficient under the Load Conditions Ranged from 0.056 to 0.1240.

Experiment and simulation of friction coefficient of polyoxymethylene

2018 ◽  
Vol 70 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Xiaoshuang Xiong ◽  
Lin Hua ◽  
Xiaojin Wan ◽  
Can Yang ◽  
Chongyang Xie ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Friction Force ◽  
Normal Load ◽  
Fe Model ◽  
Sliding Velocity ◽  
Experiment Data ◽  
Simulation Data ◽  
Content Type

Purpose The purposes of this paper include studying the friction coefficient of polyoxymethylene (POM) under a broad range of normal load and sliding velocity; developing a mathematical model of friction coefficient of POM under a broad range of normal loads and sliding velocities; and applying the model to dynamic finite element (FE) analysis of mechanical devices containing POM components. Design/methodology/approach Through pin-on-disc experiment, the friction coefficient of POM in different normal loads and sliding velocities is investigated; the average contact pressure is between 5 and 15 Mpa and the sliding velocity is from 0.05 to 0.9 m/s. A friction algorithm is developed and embedded in the FE model to simulate the friction of POM in different normal loads and sliding velocities. Findings The friction coefficient of POM against steel declines with the increase of normal loads when the contact pressure is between 5 and 15 Mpa. The friction coefficient of POM against steel increases markedly when the sliding velocity is between 0.05 and 0.15 m/s, it decreases sharply between 0.15-0.45 m/s and then it stabilizes at high sliding velocity between 0.45 and 0.9 m/s. The friction coefficient of POM in different working operations has a significant effect on contact stress and shear stress. The simulation data and experiment data of POM friction force fit very well; therefore, it can be concluded that the friction algorithm and FE model are accurate. Originality/value The friction coefficient of POM under a broad range of normal loads and sliding velocities is investigated. The friction coefficient model of POM is established as a function of normal loads and sliding velocities in the dry sliding condition. A friction algorithm is developed and embedded in the FE model of the friction of POM. The mathematical model of the friction coefficient accurately agrees with the experiment data, and simulation data and experiment data of the POM friction force fit very well.

Friction Coefficient and Wear Rate of Different Materials Sliding Against Stainless Steel

2013 ◽  
Vol 1 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Dewan Muhammad Nuruzzaman ◽  
Mohammad Asaduzzaman Chowdhury
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Normal Load ◽  
304 Stainless Steel ◽  
Sliding Velocity ◽  
Stainless Steel 304 ◽  
Different Types ◽  
Pin On Disc ◽  
Ss 304

This paper examines the relation between friction/wear and different types of steel materials under different normal loads and sliding velocities and to explore the possibility of adding controlled normal load and sliding velocity to a mechanical process. In order to do so, a pin on disc apparatus is designed and fabricated. Experiments are carried out when different types of disc materials such as stainless steel 304 (SS 304), stainless steel 316 (SS 316) and mild steel slide against stainless steel 304 (SS 304) pin. Variations of friction coefficient with the duration of rubbing at different normal loads and sliding velocities are investigated. Results show that friction coefficient varies with duration of rubbing, normal load and sliding velocity. In general, friction coefficient increases for a certain duration of rubbing and after that it remains constant for the rest of the experimental time. The obtained results reveal that friction coefficient decreases with the increase in normal load for all the tested materials. It is also found that friction coefficient increases with the increase in sliding velocity for all the materials investigated. Moreover, wear rate increases with the increase in normal load and sliding velocity. At identical operating condition, the magnitudes of friction coefficient and wear rate are different for different materials depending on sliding velocity and normal load.

Friction Characteristics and Adhesion Force Under Low Normal Load

1995 ◽  
Vol 117 (4) ◽  
pp. 569-574 ◽  
Author(s):  
Yasuhisa Ando ◽  
Yuichi Ishikawa ◽  
Tokio Kitahara
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Adhesion Force ◽  
Normal Load ◽  
Adhesion Forces ◽  
Test Pieces ◽  
Before And After ◽  
Constant Normal Load ◽  
The Mean ◽  
Steel Balls

The friction coefficient and adhesion force between steel balls and flat test pieces were measured during friction under low normal load in order to examine the tribological characteristics. First, the friction coefficients were measured under a constant normal load of 0.8 to 2350 μN, and the adhesion forces were measured before and after each friction. The result showed that the friction coefficient was highest at low normal loads, while the friction force divided by the sum of the normal load and the mean adhesion force was almost constant over the whole range of loads. Second, when the normal load was reduced gradually during friction, friction still acted when the normal load became negative and a pulling off force was applied to the surface. Thus an adhesion force acts during friction and this adhesion force affects the friction force in the same way as the normal load.

The effect of serpentine additive on energy-saving and auto-reconditioning surface layer formation

2017 ◽  
Vol 69 (2) ◽  
pp. 158-165 ◽  
Author(s):  
Xiao Wang ◽  
Junwei Wu ◽  
Xicheng Wei ◽  
Rende Liu ◽  
Qi Cao
Keyword(s):  
Surface Layer ◽  
Friction Coefficient ◽  
Mass Loss ◽  
Energy Saving ◽  
Normal Load ◽  
Lubricant Additive ◽  
Test Machine ◽  
Content Type ◽  
Saving Effect ◽  
Worn Surface

Purpose This paper aims to investigate the energy-saving effect and mechanism of serpentine as lubricant additive in the simulated condition. Design/methodology/approach An ABLT-1 bearing test machine was used for 1,350 hours and an MM-W1 three-pin-on-disk apparatus was used to investigate its anti-friction effect. The worn surface was characterized by scanning electron microscopy equipped with energy dispersive spectroscopy. Findings The results show that the energy-saving effect was improved after adding serpentine powder in oil and that both the friction coefficient and mass loss were dramatically decreased. The analysis on worn surface layer demonstrates that an auto-reconditioning surface layer was formed on the worn surface, which was responsible for the decrease in friction and wear. Originality/value The simulation test for the metal bearing was conducted over 1,350 hours using lubricant with and without serpentine powder. The addition of serpentine powder enhanced the energy-saving rate over time, stabilizing at about 13 per cent after 1,000 hours. An auto-reconditioning surface layer was formed on the surfaces of disassembled bearing lubricated with serpentine doped oil, resulting in dramatic decrease of both the friction coefficient and the mass loss. In addition to normal load and the accumulation of serpentine powder in the furrows and scratches of the deformed layer, the formation of the surface layer was possibly related to the substrate deformation induced by friction force.

scholarly journals Modeling and Analysis for Wear Performance in Dry Sliding of Epoxy/Glass/PTW Composites Using Full Factorial Techniques

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
M. Sudheer ◽  
Ravikantha Prabhu ◽  
K. Raju ◽  
Thirumaleshwara Bhat
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Hybrid Composites ◽  
Normal Load ◽  
Glass Fibers ◽  
Dry Sliding Wear ◽  
Dry Sliding ◽  
Sliding Velocity ◽  
Wear Performance ◽  
Full Factorial

The dry sliding friction and wear behavior of epoxy hybrid composites reinforced with glass fibers and a varying amount of potassium titanate whiskers (PTWs) fabricated by vacuum hand layup method were studied. The influence of normal load, sliding velocity, and whisker content on both friction coefficient and specific wear rate was investigated on a pin-on-disc machine. The tests were conducted at ambient conditions based on the 3 × 3 (3 factors at 3 levels) full factorial design. Analysis of variance (ANOVA) was performed to obtain the contribution of control parameters on friction coefficient and wear rate. The density and hardness of the composites were found to be enhanced with the PTW loading. The friction coefficient and wear resistance of the hybrid composites were found to be improved with the whisker content and were also greatly influenced by normal load and sliding velocity. A correlation between dry sliding wear behaviors of composites with wear parameters was obtained by multiple regressions. The worn out surface of selected samples was observed under scanning electron microscope (SEM) to identify wear mechanisms. This study revealed that the addition of the ceramic microfillers such as PTW improves the wear performance of the epoxy/glass polymer composites significantly.

Effect of Velocity and Load on the Development of Kinetic Friction at a Lubricated Steel on Polymer Interface

2012 ◽  
Author(s):  
Matthew M. Bunten ◽  
Shannon J. Timpe
Keyword(s):  
Friction Coefficient ◽  
Adhesion Force ◽  
Normal Load ◽  
Polymer Surface ◽  
Sliding Velocity ◽  
Disk Interface ◽  
Synthetic Hydrocarbon ◽  
Velocity Effect ◽  
Adhesive Effect ◽  
Soft Disk

The effect of normal load and sliding velocity on the development of friction at a lubricated steel pin on polymer disk interface was investigated. Polyoxymethylene homopolymer disks were lubricated with a lithium soap thickened synthetic hydrocarbon grease and tested against a 6 mm diameter stainless steel pin. The normal load was varied from 3 to 80 N, and the sliding velocity was varied from 0.0004 to 0.2 m/s. The engineering friction coefficient displayed a power law dependence on the external applied load, indicating a significant adhesive effect in the presence of the lubricant. The true friction coefficient was 0.04, and the average adhesion force was calculated to be 29 N. With the soft disk and hard pin configuration, velocity and time effects were found to be negligible in the presence of the dominant dependence on the normal load. However, a velocity effect emerged with steel disks and polymer pins, likely due to a temperature rise at the polymer surface.

Micro-Tribological Behavior of Boron Carbide Self-Mated Pairs

2007 ◽  
Vol 336-338 ◽  
pp. 1740-1742
Author(s):  
Fang Wu ◽  
Sheng Ming Xu ◽  
Song Zhe Chen ◽  
Lin Yan Li ◽  
Gang Xu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Boron Carbide ◽  
Tribological Properties ◽  
Tribological Behavior ◽  
Normal Load ◽  
The Self ◽  
Sliding Velocity ◽  
Oxidation Treatment ◽  
Sliding Distance

Tribological behavior of B4C-SiC self-mated pairs was studied, and pre-oxidation treatment was adopted to improve the tribological properties of B4C-SiC. At the same SiC content, self-friction coefficient of B4C-SiC decreases with the increase of sliding distance, normal load, and sliding velocity; while the increasing of SiC content leads to increase of both self-friction coefficient and ware rate, which was determined to be within the range of 0.8×10-6~5.8×10-6 mm3·N-1·m-1. Pre-oxidation treatment of the B4C-SiC resulted in the formation of B2O3/H3BO3 lubricant layers, which effectively reduced the self-friction coefficient.

Experimental Investigation on Friction Coefficient of Engineering Polymers Sliding against Different Counterface Materials

2014 ◽  
Vol 903 ◽  
pp. 90-95
Author(s):  
Mohammad Lutfar Rahaman ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman
Keyword(s):  
Experimental Investigation ◽  
Stainless Steel ◽  
Friction Coefficient ◽  
Mild Steel ◽  
Normal Load ◽  
Operating Conditions ◽  
The Other ◽  
Sliding Velocity ◽  
Friction Process ◽  
Engineering Polymers

In this research, friction coefficients of engineering polymers such as nylon and polytetrafluoroethylene (PTFE) are investigated under normal load and sliding velocity. Experiments are conducted when nylon and PTFE slide against different counterface pin materials such as mild steel and stainless steel 202 (SS 202). Experiments are carried out at different normal loads 2, 4 and 6 N, and sliding velocities 0.2, 0.4 and 0.6 m/s. Results show that in general, friction coefficient of nylon decreases with the increase in normal load and sliding velocity. On the other hand, during friction process, PTFE shows different trend i.e. friction coefficient of PTFE increases with the increase in normal load and sliding velocity. Moreover, it is observed that at identical operating conditions, the values of friction coefficient of nylon and PTFE are different depending on normal load, sliding velocity and counterface material.

Forced Response of Shrouded Blades With Intermittent Dry Friction Force

2008 ◽  
Author(s):  
Weiwei Gu ◽  
Zili Xu ◽  
Lv Qiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Forced Response ◽  
Gap Size ◽  
Algebraic Equations ◽  
Friction Damper ◽  
Friction Forces ◽  
Contact Points

The gap friction damper model is presented in this paper, which is employed to simulate the friction forces at the contact points of the shroud interface. Using the harmonic balance method (HBM), the friction force can be approximated by a series of harmonic functions. The governing differential equations of blade motion are transformed into a set of nonlinear algebraic equations, which can be solved iteratively to yield the steady-state response. The results show that the forced response is attenuated due to the additional damping introduced by frictional slip. The predicted results agree well with those of the Runge-Kutta method. In addition, the effect of parameters of damping structures such as the gap size, friction coefficient and normal load on the forced response of blades were studied. The results show that increasing the damper gap size causes a increase in resonant response. However, the increment isn’t obvious. In addition, an increase in friction coefficient or normal load decreases the forced response of blade.

Friction Force Microscopy Investigation of Elastic Instabilities in Nanolubricated Junctions

2005 ◽  
Author(s):  
R. Buzio ◽  
C. Boragno ◽  
F. Buatier de Mongeot ◽  
U. Valbusa
Keyword(s):  
Friction Force ◽  
Normal Load ◽  
Experimental Results ◽  
Friction Force Microscopy ◽  
Sliding Velocity ◽  
Force Microscopy ◽  
Microscopy Investigation ◽  
Elastic Instabilities

We present experimental results concerning the Friction Force Microscopy (FFM) investigation of smooth mica and Si surfaces lubricated by a model lubricant. We have studied the friction force as a function of normal load and sliding velocity, analyzing results in the framework of interfacial liquid structuring and drainage effects.

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