Influence of the pulverized coal content on the relationship between the slip ratio and the coefficient of friction when the rollers roll on the layered coal

2019 ◽  
Vol 2019.57 (0) ◽  
pp. 913
Author(s):  
Masayuki HAGIHARA ◽  
Kentaro OSHIRO ◽  
Kazuhiro WATANABE ◽  
Emi OHNO ◽  
Akira KOBAYASHI ◽  
...  
Keyword(s):  
Coefficient Of Friction ◽  
Pulverized Coal ◽  
Slip Ratio ◽  
The Coefficient Of Friction ◽  
The Relationship

Experimental study on the relationship between the friction coefficient and interference in locomotive axle press-fitting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Friction Pair ◽  
Rolling Stock ◽  
Content Type ◽  
Press Fitting ◽  
The Press ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Locomotive Wheels

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.

Investigation of the causes of damage to freight cars during disbanding on non-mechanized sorting slides and development of measures to prevent them

2021 ◽  
pp. 4-13
Author(s):  
S. V. Tankeev ◽  
◽  
A. E. Kolodin ◽  
V. B. Sverdlov ◽  
A. V. Nazarov ◽  
...  
Keyword(s):  
Low Power ◽  
Coefficient Of Friction ◽  
Damage Assessment ◽  
Laboratory Tests ◽  
Rolling Stock ◽  
Third Body ◽  
Normative Documents ◽  
The Coefficient Of Friction ◽  
Loading And Unloading ◽  
The Relationship

The damage assessment of freight cars during shunting and loading and unloading operations was made. The need to review the normative documents regulating the relationship between the owners of rolling stock, owners of non-public tracks and the carrier is noted. The reasons for formation of damage on the wheel pairs of freight cars when disbanding on low-power sorting slides are considered. The conditions for ensuring the deceleration of detachments on non-mechanized sorting slides without damaging the wheels are determined. The analysis of methods for ensuring braking on low-power slides is carried out. A method was chosen to ensure the wheel set rotation by introducing a third body between the rubbing surfaces during the braking of cars, which will take over a part of the resulting heat flow, reducing the temperature and increasing the coefficient of friction in the «wheel-rail» contact zone. A method is proposed to provide braking on the non-mechanized sorting slide during shoe braking by applying a friction compound to a non-working rail. Laboratory tests were carried out, which showed that the introduction of a friction additive can achieve the necessary coefficient of friction to comply with the standard parameters of deceleration of the car in the braking zone.

scholarly journals The Effect of Elemental Composition and Nanostructure of Multilayer Composite Coatings on Their Tribological Properties at Elevated Temperatures

2020 ◽  
Author(s):  
Alexey Vereschaka ◽  
Sergey Grigoriev ◽  
Vladimir Tabakov ◽  
Mars Migranov ◽  
Nikolay Sitnikov ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Elevated Temperatures ◽  
Composite Coatings ◽  
Multilayer Composite ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Tribological Parameters ◽  
Adhesion Component

The chapter discusses the tribological properties of samples with multilayer composite nanostructured Ti-TiN-(Ti,Cr,Al,Si)N, Zr-ZrN-(Nb,Zr,Cr,Al)N, and Zr-ZrN-(Zr,Al,Si)N coatings, as well as Ti-TiN-(Ti,Al,Cr)N, with different values of the nanolayer period λ. The relationship between tribological parameters, a temperature varying within a range of 20–1000°C, and λ was investigated. The studies have found that the adhesion component of the coefficient of friction (COF) varies nonlinearly with a pronounced extremum depending on temperature. The value of λ has a noticeable influence on the tribological properties of the coatings, and the nature of the mentioned influence depends on temperature. The tests found that for the coatings with all studied values of λ, an increase in temperature first caused an increase and then a decrease in COF.

Prediction of the Coefficient of Friction for Pneumatic Tyres on Hard Pavement

1975 ◽  
Vol 189 (1) ◽  
pp. 259-266
Author(s):  
Shri Kant ◽  
D. L. Prasanna Rao ◽  
M. L. Munjal
Keyword(s):  
Coefficient Of Friction ◽  
Vertical Load ◽  
Contact Patch ◽  
The Coefficient Of Friction ◽  
The Relationship

The relationship between the coefficient of friction and the slip of a flexible wheel, such as the pneumatic tyre, plays a major role in the design of refined braking systems for vehicles. The available data being partly empirical in nature, it was desirable to be able to predict this relationship. In this paper an attempt is made to explain the mechanism defining this relationship for a pneumatic tyre operating on a hard pavement. The distinct roles of the flexibility of the tyre and the sliding of the wheel are identified and utilized in predicting the curve. A model of the tyre is proposed to explain the role of flexibility of the tyre. It is shown that the procedure suggested here can clearly bring out the effects of some of the operating paramenters of the vehicle, such as speed of the vehicle, presence of contaminants in the contact patch, stiffness of the tyre, and vertical load on the wheel.

A Contribution to the Theory of Friction and Wear and the Relationship between them

1976 ◽  
Vol 190 (1) ◽  
pp. 477-488 ◽  
Author(s):  
J. Halling
Keyword(s):  
Shear Stress ◽  
Coefficient Of Friction ◽  
Interfacial Shear Stress ◽  
Failure Criteria ◽  
Elastic Behaviour ◽  
Total Load ◽  
Perfectly Plastic ◽  
The Coefficient Of Friction ◽  
Wear Law ◽  
The Relationship

The nature of the interaction between a rigid spherical asperity and an asperity governed by the stress/strain law [Formula: see text] is studied. The interfacial shear stress is defined by f τmax where 0 < f < 1, τ maxbeing the maximum allowable shear stress at the contact. By integrating the total effect of a population of such surface asperities expressions for the total frictional forces, and the total load are derived. The value of the coefficient of friction is thus obtained and the special conditions for perfectly plastic and elastic behaviour are considered. In both cases the friction coefficient is seen to contain a term defined by the deformation and dependent on surface roughness and a term totally defined by f. Using the same model a fatigue type failure criteria is introduced to predict the volume of wear. It is then possible to produce a wear law which is consistent with experience and which includes the relationship between the wear and the coefficient of friction.

EXPERIMENTAL STUDY OF THE ROLLING–SLIDING CONTACT CONDITIONS IN A PA66/STEEL GEAR USING TWIN-DISC TEST RIG: FRICTION AND WEAR ANALYSIS

2015 ◽  
Vol 22 (06) ◽  
pp. 1550074
Author(s):  
MEFTAH MBAREK ◽  
SADOK RHAIEM ◽  
MOHAMED KHARRAT ◽  
MAHER DAMMAK
Keyword(s):  
Coefficient Of Friction ◽  
Angular Speed ◽  
Linear Increase ◽  
Contact Temperature ◽  
Test Rig ◽  
Contact Conditions ◽  
Slip Ratio ◽  
The Coefficient Of Friction ◽  
Adhesive Interactions ◽  
Different Diameters

This study investigates the effects of sliding ratio on the tribological response of the contact between the teeth of a metal/polymer gear in the regions close to the pitch point. For this purpose, a new twin-disc test rig was developed on the basis of two discs of different diameters rotating one above the other at the same angular speed. Two different materials were used: non-alloyed structural steel (C45) and polyamide (PA66). The effect of the slip ratio (4%, 12%, 20% and 28%) was studied at a constant pressure of 34 MPa and a constant angular speed of 300 rpm. In addition, the contact conditions were controlled with measurements of the two discs surface temperatures. The results indicate that the wear and the friction are closely related to the contact temperature generated by the sliding phenomenon. At low slip ratio (4% and 12%), the coefficient of friction and the temperature are characterized by a quasi-linear increase with time, and the wear increases slowly. At higher slip ratio (20% and 28%), the coefficient of friction and the temperature presents a steady state, and the wear increases dramatically. During the test, a film of transferred PA66 is formed on the steel surface causing the development of adhesive interactions between the contacting discs which increase the friction coefficient and the contact temperature. The high thermal conductivity of steel as compared to that of the polymer can reduce enormously the contact temperature generated by the sliding process.

Research of the effect of shot peening vibro-abrasive machining on the properties of the steel NC11LV

Mechanik ◽  
2017 ◽  
Vol 90 (1) ◽  
pp. 74-75
Author(s):  
Sławomir Spadło ◽  
Damian Bańkowski ◽  
Joanna Kowalczyk
Keyword(s):  
Coefficient Of Friction ◽  
Shot Peening ◽  
Friction And Wear ◽  
Abrasive Machining ◽  
Tribological Tests ◽  
Working Medium ◽  
The Coefficient Of Friction ◽  
Relationship Of ◽  
The Relationship

The article presents the results of the effect of vibro-abrasive machining using as a working medium balls of steel-check on the properties of disks made of steel NC11 (X160CrMoV121). Tribological tests using the tester T-01 made it possible to determine the relationship of time of shot peening on the coefficient of friction and wear linear-in. They were presented typical consumption profiles.

scholarly journals The Role of Friction and Tangential Compliance on the Resultant Launch Angle of a Golf Ball

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 27
Author(s):  
Erik Henrikson ◽  
Paul Wood ◽  
Chris Broadie ◽  
Tom Nuttall
Keyword(s):  
Theoretical Model ◽  
Coefficient Of Friction ◽  
Coulomb Friction ◽  
Golf Ball ◽  
Golf Club ◽  
The Coefficient Of Friction ◽  
Hertzian Impact ◽  
The Relationship ◽  
Launch Angle

A thorough understanding of how the delivered face angle and club path of a golf club influences the initial launch direction of a golf ball can play a significant role in the design of various club types as well as help players and coaches better understand performance in the field. A theoretical model based on a Hertzian impact formulation with the inclusion of tangential compliance via Coulomb friction is compared to empirical results. This comparison demonstrates that the initial launch direction of a golf ball for a given club path and face angle can be sufficiently predicted by the theoretical model, providing insights into the mechanisms leading to different launch direction percentages relative to face angle for various club types. Additionally, the relationship between launch direction and the coefficient of friction is explored for various angles of incidence.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

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