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.

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.

A novel technique for modeling friction behavior in knitted fabric simulation

2017 ◽  
Vol 29 (6) ◽  
pp. 776-792
Author(s):  
Vajiha Mozafary ◽  
Pedram Payvandy
Keyword(s):  
Friction Coefficient ◽  
Uniform Distribution ◽  
Friction Force ◽  
Experimental Result ◽  
Knitted Fabric ◽  
Friction Behavior ◽  
Content Type ◽  
Novel Technique ◽  
Fabric Structure ◽  
Fabric Surface

Purpose Fabric-object friction force is a fundamental factor in cloth simulation. A large number of parameters influence the frictional properties of fabrics such as fabric structure, yarn structure, and inherent properties of component fibers. The purpose of this paper is to propose a novel technique for modeling fabric-object friction force in knitted fabric simulation based on the mass spring model. Design/methodology/approach In this technique, unlike other studies, distribution of friction coefficient over the fabric surface is not uniform and depends on the fabric structure. The main reason for considering non-uniform distribution is that in various segments of fabric, contact percent of fabric-object is different. Findings The proposed technique and common methods based on friction coefficient uniform distribution are used to simulate the frictional behavior of knitted fabrics. The results show that simulation error values for proposed technique and common methods are 2.7 and 9.4 percent as compared with the experimental result, respectively. Originality/value In the existing methods of the friction force modeling, the friction coefficient of fabric is assumed uniform. But this assumption is not correct because fabric does not have an isotropic structure. Thus in this study, the friction coefficient distribution is considered based on fabric structure to achieve more of realistic simulations.

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.

Friction Behavior Between Epoxy and Flexible Pipes Armor Wires

2016 ◽  
Author(s):  
Diego A. Lorio ◽  
Facundo J. Wedekamper ◽  
Fabiano Bertoni ◽  
Facundo S. Lopéz ◽  
George C. Campello ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Contact Pressure ◽  
Normal Load ◽  
Surface Profile ◽  
Repeated Measurements ◽  
Analytical Models ◽  
Friction Coefficients ◽  
Wire Sample ◽  
Flexible Pipes ◽  
The Wire

The offshore industry has presented an increasing demand over the last few decades, requiring the production in deep water fields. The end fittings (EF) are critical points within the production system. Therefore, structural and fatigue analyses are essential in the EF design, making it necessary to know the stress distribution experienced by the armor wires along the EF. Numerical and analytical models are often used in order to assess the stress state. However, characteristics like geometries, materials and interactions must be previously known in order to apply these models. The purpose of this work was to analyze the arithmetic mean surface roughness (Ra) and to determine the friction coefficient (μ) for two types of armor wires when in contact with resin used to fill the EF. The resin used in the interaction with the armor wires was an epoxy filled with metallic particles. For the experimental analysis straight carbon steel armor wires with different cross-sections, typically used in 2.5″ and 8″ flexible pipes were used. Surface profile was obtained for each wire by repeated measurements along two lines over each surface. A total of three repetitions were performed in each measure line. Longitudinal roughness was determined through these profiles. Finally, friction coefficients were obtained experimentally by means of a device that allows to simulate the wire pullout and sliding process. In this device, two epoxy pads were put in contact with the surface of the analyzed wire sample, and rigid bodies in contact with the pads were used to ensure that the normal load applied is transmitted uniformly through the contact surface. The displacement rate, contact pressure between the surface of the wire and the epoxy resin pads, and axial force were recorded. The roughness in the longitudinal direction of the wires was analyzed through descriptive statistic and compared by Student’s “t” test. The highest values were obtained on wires with larger sections. This behavior is exposed on the results obtained for the friction coefficient as a function of the contact pressure. Friction coefficient for both wires was analyzed and compared using a Mann-Whitney U test. Both friction coefficients have a positive slope, indicating a small increase as the contact pressure raise. The significance value obtained for the means comparisons was p = 0.0001 and confirms that the average friction coefficient of the two wires are really different. Because of that, we conclude that is necessary to treat the EF project for different flexible pipes differentially.

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.

Friction and wear behavior of hydrogenated diamond-like carbon coating against titanium alloys under large normal load and variable velocity

2017 ◽  
Vol 69 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Jun Liu ◽  
Zhinan Zhang ◽  
Zhe Ji ◽  
Youbai Xie
Keyword(s):  
Friction Coefficient ◽  
Service Life ◽  
Carbon Coating ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Diamond Like Carbon ◽  
Content Type ◽  
Friction And Wear Behavior ◽  
Dlc Coating

Purpose This paper aims to investigate the effects of reciprocating frequency, large normal load on friction and wear behavior of hydrogenated diamond-like carbon (H-DLC) coating against Ti-6Al-4V ball under dry and lubricated conditions. Design/methodology/approach The friction and wear mechanisms are analyzed by scanning electron microscope, energy dispersive spectroscopy and Raman spectroscopy. Findings The results show that as reciprocating frequency increases under lubricated conditions, the friction coefficient decreases first and then increases. When the reciprocating frequency is 2.54 Hz, the value of friction coefficient reaches the minimum. The friction reduction is because of the transformation from sp3 to sp2, the formation of transfer layer on Ti-6Al-4V ball and the reduction in viscous friction, whereas the increase of friction coefficient is related to wear. In dry conditions, the friction coefficient is between 0.06 and 0.1. And, the service life of H-DLC coating decreases with the increase in reciprocating frequency and normal load. Research limitations/implications It is confirmed that adding the lubricant could prolong the service life of H-DLC coating and reduce friction and wear efficiently. And, the wear mechanisms under dry and lubricated conditions encompass abrasive wear and adhesive wear. Originality/value The results are helpful for application of diamond-like carbon coating.

scholarly journals The kinetic friction of saline ice against itself at low sliding velocities

1991 ◽  
Vol 15 ◽  
pp. 242-246 ◽  
Author(s):  
D. E. Jones ◽  
F. E. Kennedy ◽  
E. M. Schulson
Keyword(s):  
Experimental Investigation ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Testing System ◽  
Kinetic Friction ◽  
Sliding Velocity ◽  
Sliding Interface ◽  
The Mean ◽  
Peak Value

An experimental investigation was performed on the kinetic friction coefficient of laboratory-grown, columnar saline ice sliding against itself. Tests were performed on a dual-opposing load apparatus specially manufactured for attachment to an MTS testing system. The mean kinetic friction coefficient, μ, was measured for sliding velocities from 10−6 to 5 × 10−2 m s−1 at temperatures from —3° to —40°C under a contact pressure of about 20 kPa. The ice specimens were oriented with grain columns perpendicular to the sliding interface. At -3°C and at —10°C, three distinct regions were observed: from 10−6 to about 10−5ms−1, μwas nearly constant at 0.5; at velocities from 10−5 to 10−3 m s−1, μ began to drop rapidly to about 0.1; and, above 10−3 m s−1, μ began to level off at ~0.05. The velocity at which μ began to decline increased with decreasing temperature. At temperatures below —10°C, μ increased from ~0.5 at v =10−6ms−1 to a peak value of ~0.7 near a velocity of 5 × 10−5ms−1 and then fell rapidly to about 0.1 at 10−2ms−1. In general, μ increased with decreasing temperature and sliding velocity.

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