ASSESSMENT OF THE INFLUENCE OF THE COEFFICIENT
OF FRICTION ON THE TEMPERATURE DISTRIBUTION OF A DISC
BRAKE DURING THE BRAKING PROCESS

Brake assemblies are key mechanisms in the aspect of safe and reliable operation of devices and machines. Due to intense thermal processes that occur during braking, the brakes are exposed to an accelerated wear. The article assesses the impact of tribological cooperation conditions between the caliper and the disc of a disc brake on the temperature of a disc. The variable value in the simulations was the coefficient of friction between the cooperating surfaces. A direct effect of the increase of the analysed parameter on the enhancement of brake elements’ temperature was found. At the same time, a similar nature of thermal processes was observed for all values of the friction coefficient taken into account.

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

International Journal of Structural Integrity ◽

10.1108/ijsi-01-2021-0007 ◽

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.

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Anisotropic Vibration Tactile Model and Human Factor Analysis for a Piezoelectric Tactile Feedback Device

Micromachines ◽

10.3390/mi10070448 ◽

2019 ◽

Vol 10 (7) ◽

pp. 448 ◽

Cited By ~ 1

Author(s):

Jichun Xing ◽

Huajun Li ◽

Dechun Liu

Keyword(s):

Friction Coefficient ◽

Coefficient Of Friction ◽

Ciliary Body ◽

Human Factor ◽

Sliding Friction ◽

Excitation Frequency ◽

Tactile Feedback ◽

Body Structure ◽

Full Coverage ◽

The Coefficient Of Friction

Tactile feedback technology has important development prospects in interactive technology. In order to enrich the tactile sense of haptic devices under simple control, a piezoelectric haptic feedback device is proposed. The piezoelectric tactile feedback device can realize tactile changes in different excitation voltage amplitudes, different excitation frequencies, and different directions through the ciliary body structure. The principle of the anisotropic vibration of the ciliary body structure was analyzed here, and a tactile model was established. The equivalent friction coefficient under full-coverage and local-coverage of the skin of the touch beam was deduced and solved. The effect of system parameters on the friction coefficient was analyzed. The results showed that in the full-coverage, the tactile effect is mainly affected by the proportion of the same directional ciliary bodies and the excitation frequency. The larger the proportion of the same direction ciliary body is, the smaller the coefficient of friction is. The larger the excitation frequency is, the greater the coefficient of friction is. In the local-coverage, the tactile effect is mainly affected by the touch position and voltage amplitude. When changing the touch pressure, it has a certain effect on the change of touch, but it is relatively weak. The experiment on the sliding friction of a cantilever touch beam and the experiment of human factor were conducted. The experimental results of the sliding friction experiment are basically consistent with the theoretical calculations. In the human factor experiment, the effects of haptic regulation are mainly affected by voltage or structure of the ciliary bodies.

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Effect of Iron Oxide Nanoparticles on the Properties of Water-Based Drilling Fluids

Energies ◽

10.3390/en13246718 ◽

2020 ◽

Vol 13 (24) ◽

pp. 6718

Author(s):

Muhammad Awais Ashfaq Alvi ◽

Mesfin Belayneh ◽

Sulalit Bandyopadhyay ◽

Mona Wetrhus Minde

Keyword(s):

Iron Oxide ◽

Coefficient Of Friction ◽

Drilling Fluid ◽

Precipitation Method ◽

Fluid Loss ◽

Drilling Fluids ◽

The Coefficient Of Friction ◽

Filtrate Loss ◽

Co Precipitation ◽

The Impact

In recent years, several studies have indicated the impact of nanoparticles (NPs) on various properties (such as viscosity and fluid loss) of conventional drilling fluids. Our previous study with commercial iron oxide NPs indicated the potential of using NPs to improve the properties of a laboratory bentonite-based drilling fluid without barite. In the present work, iron oxide NPs have been synthesized using the co-precipitation method. The effect of these hydrophilic NPs has been evaluated in bentonite and KCl-based drilling fluids. Rheological properties at different temperatures, viscoelastic properties, lubricity, and filtrate loss were measured to study the effect of NPs on the base fluid. Also, elemental analysis of the filtrate and microscale analysis of the filter cake was performed. Results for bentonite-based fluid showed that 0.019 wt% (0.1 g) of NPs reduced the coefficient of friction by 47%, and 0.0095 wt% (0.05 g) of NPs reduced the fluid loss by 20%. Moreover, for KCl-based fluids, 0.019 wt% (0.1 g) of additive reduced the coefficient of friction by 45%, while higher concentration of 0.038 wt% (0.2 g) of NPs shows 14% reduction in the filtrate loss. Microscale analysis shows that presence of NPs in the cake structure produces a more compact and less porous structure. This study indicates that very small concentration of NPs can provide better performance for the drilling fluids. Additionally, results from this work indicate the ability of NPs to fine-tune the properties of drilling fluids.

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A novel nonlinear nano-scale wear law for metallic brake pads

Physical Chemistry Chemical Physics ◽

10.1039/c8cp01061g ◽

2018 ◽

Vol 20 (17) ◽

pp. 12027-12036 ◽

Cited By ~ 1

Author(s):

Sandeep P. Patil ◽

Sri Harsha Chilakamarri ◽

Bernd Markert

Keyword(s):

Molecular Dynamics ◽

Temperature Distribution ◽

Coefficient Of Friction ◽

Friction And Wear ◽

Brake Pads ◽

Braking System ◽

System P ◽

The Coefficient Of Friction ◽

Dynamics Simulations ◽

Wear Law

In the present work, molecular dynamics simulations were carried out to investigate the temperature distribution as well as the fundamental friction characteristics such as the coefficient of friction and wear in a disc-pad braking system.

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The Size of the Friction Coefficient Depending on the Size and Course of Normal Load

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.474.303 ◽

2014 ◽

Vol 474 ◽

pp. 303-308 ◽

Cited By ~ 4

Author(s):

Eva Labašová

Keyword(s):

Friction Coefficient ◽

Coefficient Of Friction ◽

Normal Load ◽

Testing Machine ◽

Constant Load ◽

Current Component ◽

Rectangular Shape ◽

The Coefficient Of Friction ◽

Ring Method ◽

Run Up

The coefficient of friction for the bronze material (CuZn25Al6) with inset graphite beds is investigated in the present paper. Friction coefficient was investigated experimentally by the testing machine Tribotestor`89 which uses the principle of the ring on ring method. Tribotestor`89 machine may be classed to the rotary tribometers. The tested sliding pairs were of the same material. The internal bushing performed a rotational movement with constant sliding speed (v = 0.8 m s-1). The external fixed bushing was exposed to the normal load, which was of different sizes and different variations. Process of load was increased from level 50 N to 200 N (400 N, 600 N) during run up 600 s, after the run up the appropriate level of load was held.The forth test had a rectangular shape of loading with direct current component 400 N and the amplitude 200 N period 600 s, the whole test took 1800 s. The obtained results reveal that friction coefficient decreases with the increase of normal load. Further, that the coefficient of friction was found smaller at constant load, as compared to rectangular shape of loading.

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The vibration of the friction pads of disc brake in the aspect of changing the coefficient of friction

Rail Vehicles ◽

10.53502/rail-138465 ◽

2017 ◽

pp. 62-68

Author(s):

Wojciech Sawczuk

Keyword(s):

Coefficient Of Friction ◽

Disc Brake ◽

The Coefficient Of Friction

W pojazdach szynowych ze względu na coraz to większe prędkości jazdy prowadzi się prace nad udoskonalaniem układów hamulcowych tak, aby zatrzymanie pojazdu odbyło się na możliwie najkrótszej drodze hamowania. Niestabilność pracy wynika między innymi z występowania drgań na styku elementów ciernych, co wpływa na obniżenie sprawności procesu hamowania. W praktyce oznacza to, że podczas hamowania pojazdów występujący zmienny w czasie opór tarcia może być powodem nierównomiernego przebiegu procesu hamowania. Skutki tych zmian mogą objawić się w postaci drgań samowzbudnych. Celem artykułu jest przedstawienie związku zmian chwilowego współczynnika tarcia hamulca tarczowego ze zmianami chwilowych przyspieszeń drgań okładziny ciernej w czasie hamowania.

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Research of the drawing of bars plate in the refiners

Journal of Physics Conference Series ◽

10.1088/1742-6596/2094/4/042038 ◽

2021 ◽

Vol 2094 (4) ◽

pp. 042038

Author(s):

S N Vikharev ◽

VA Morkovin

Keyword(s):

Friction Coefficient ◽

Contact Interaction ◽

Coefficient Of Friction ◽

Wood Pulp ◽

Contact Processes ◽

Low Concentration ◽

The Coefficient Of Friction ◽

Radial Arrangement

Abstract Object of research of article is the drawing of bars plate in the refiners at refining of chips and wood pulp. On the basis of the theory of contact interaction of bars influence of the drawing of plate on characteristics of contact processes is investigated. The friction coefficient between plate decreases at increase in density of contact of bars. At increase in an angle of crossing of bars rotor and stator and refining of pulp with concentration up to 6% the coefficient of friction decreases. At increase in an angle of crossing of bars chips and pulp with concentration over 10% the coefficient of friction increases. Therefore it is recommended to increase the angle of crossing of bars rotor and stator at refining of pulp of low concentration, and at refining of pulp of concentration over 10% and chips - to reduce, up to a radial arrangement.

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Initial Selection of Disc Brake Pads Material based on the Temperature Mode

Materials ◽

10.3390/ma13040822 ◽

2020 ◽

Vol 13 (4) ◽

pp. 822 ◽

Cited By ~ 2

Author(s):

Aleksander A. Yevtushenko ◽

Piotr Grzes

Keyword(s):

Cast Iron ◽

Coefficient Of Friction ◽

Motor Vehicle ◽

Maximum Temperature ◽

Disc Brake ◽

System Of Equations ◽

Brake Pad ◽

Vehicle Velocity ◽

Braking Torque ◽

The Coefficient Of Friction

A spatial computational model of a motor vehicle disc brake, based on the system of equations of heat dynamics of friction and wear (HDFW), was developed. The interrelations of temperature-dependent coefficient of friction and coefficient of intensity of wear through the contact temperature and vehicle velocity were taken into account. The solution of the system of equations of HDFW was obtained by the finite element method (FEM) for six different brake pad materials associated with the cast-iron disc during a single braking. Changes in the braking time, coefficient of friction, braking torque, vehicle velocity, mean temperature of the contact area of the pads with the disc and wear of the friction surfaces were determined. Then, the obtained calculation results were evaluated in terms of stabilization of the coefficient of friction (braking torque), as well as minimization of the maximum temperature, wear, braking time and pads mass. As a result, recommendations were given to select optimum brake pad material in combination with a cast-iron disc.

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Coefficient of Friction for Aluminum Alloy Sheet in Contact with Polyurethane Rubber

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.26-28.320 ◽

2010 ◽

Vol 26-28 ◽

pp. 320-325 ◽

Cited By ~ 3

Author(s):

Li Li Wang ◽

Dong Sheng Li ◽

Xiao Qiang Li ◽

Liang Wang ◽

Wei Jun Yang

Keyword(s):

Aluminum Alloy ◽

Coefficient Of Friction ◽

Normal Load ◽

Orthogonal Experimental Design ◽

Sliding Velocity ◽

Stretch Forming ◽

Forming Process ◽

Alloy Material ◽

The Coefficient Of Friction ◽

The Impact

Stretch forming process of aircraft skin over reconfigurable compliant tooling is a new technology in skin manufacturing. During this process, the coefficient of friction is important for modeling accurately the process of stretch forming. The objective of this research is to measure the coefficient of friction for aluminum alloy in contact with polyurethane rubber in reciprocal sliding. An orthogonal experimental design was used to reveal the impact of four factors on the coefficient of friction, including lubrication, normal load, aluminum alloy material and sliding velocity. It is shown that lubrication is a major factor, sliding velocity is a minor factor. The influence of normal pressure is less than sliding velocity and the influence of aluminum alloy material is not very obvious. Finally, based on the experiment results, the selections of lubricant and stretching velocity are discussed in order to improve the process of stretch forming.

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