scholarly journals A Factorial Design to Numerically Study the Effects of Brake Pad Properties on Friction and Wear Emissions

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Jens Wahlström
Keyword(s):  
Factorial Design ◽  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Friction Material ◽  
Particulate Emissions ◽  
Third Body ◽  
Wear Process ◽  
Disc Brakes ◽  
The Coefficient Of Friction ◽  
Contact Situation

Airborne particulate emissions originating from the wear of pads and rotors of disc brakes contribute up to 50% of the total road emissions in Europe. The wear process that takes place on a mesoscopic length scale in the contact interfaces between the pads and rotors can be explained by the creation and destruction of contact plateaus. Due to this complex contact situation, it is hard to predict how changes in the wear and material parameters of the pad friction material will affect the friction and wear emissions. This paper reports on an investigation of the effect of different parameters of the pad friction material on the coefficient of friction and wear emissions. A full factorial design is developed using a simplified version of a previously developed cellular automaton approach to investigate the effect of four factors on the coefficient of friction and wear emission. The simulated result indicates that a stable third body, a high specific wear, and a relatively high amount of metal fibres yield a high and stable mean coefficient of friction, while a stable third body, a low specific wear, a stable resin, and a relatively high amount of metal fibres give low wear emissions.

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.

Frictionally Excited Thermoelastic Instability in Automotive Drum Brakes

1999 ◽  
Vol 122 (4) ◽  
pp. 849-855 ◽  
Author(s):  
Kwangjin Lee
Keyword(s):  
Coefficient Of Friction ◽  
Material Properties ◽  
Critical Speed ◽  
Hot Spot ◽  
Frictional Heating ◽  
Friction Material ◽  
Thermoelastic Instability ◽  
Critical Speeds ◽  
Drum Brake ◽  
The Coefficient Of Friction

Thermoelastic instability in automotive drum brake systems is investigated using a finite layer model with one-sided frictional heating. With realistic material properties of automotive brakes, the stability behavior of the one-sided heating mode is similar to that of the antisymmetric mode of two-sided heating but the critical speed of the former is higher than that of the latter. The effects of the friction coefficient and brake material properties on the critical speeds are examined and the most influential properties are found to be the coefficient of friction and the thermal expansion coefficient of drum materials. Vehicle tests were performed to observe the critical speeds of the drum brake systems with aluminum drum materials. Direct comparisons are made between the calculation and measurement for the critical speed and hot spot spacing. Good agreement is achieved when the critical speeds are calculated using the temperature-dependent friction material properties and the reduced coefficient of friction to account for the effect of intermittent contact. [S0742-4787(00)01503-4]

Some Tribological Properties of an Ionic Liquid

2005 ◽  
Author(s):  
Takashi Nogi
Keyword(s):  
Ionic Liquid ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Wear Performance ◽  
Lubrication Regime ◽  
Pin On Disc ◽  
The Coefficient Of Friction

Some tribological properties of an ionic liquid were investigated by using a pin-on-disc friction and wear tester. Due to running-in, the coefficient of friction of the ionic liquid decreased with time to a very low value of 0.02 which suggests that the lubrication regime was hydrodynamic at the end of the tests. Anti-wear performance of the ionic liquid was substantially comparable to a paraffin-based oil.

Study on the Friction and Wear Characteristics of Tungsten Carbide and Zirconium With Phosphor-Containing Liquid

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Myeong-Woo Ha ◽  
Kwang-Hee Lee ◽  
Chul-Hee Lee ◽  
Jong-Myung Choi ◽  
Jun-Wook An
Keyword(s):  
Tungsten Carbide ◽  
Coefficient Of Friction ◽  
Contact Surface ◽  
Friction And Wear ◽  
Yttrium Aluminum Garnet ◽  
Experimental Results ◽  
Wear Characteristics ◽  
Hard Materials ◽  
The Coefficient Of Friction ◽  
Friction And Wear Characteristics

The dispenser ejects the ceramic filler and phosphor-containing liquid for making various products. When the particle-containing liquid is ejected under high-velocity conditions, however, the ejection reliability decreases because of the wear of the contact surface between the rod and nozzle even though these components are made of hard materials. It is therefore necessary to characterize the friction and wear properties of the hard materials, tungsten carbide (WC) and zirconium (Zr), with the high-viscosity liquid-containing nitride or yttrium aluminum garnet (YAG) particles under reciprocating conditions. Particle contents of 15 wt.% and 30 wt.% are added to the liquid. A reciprocating test was implemented to this end, and WC and Zr specimens were used. The liquid used in the experiment contains nitride and YAG. The experimental results show that the particles inside the liquid are worn out, leading to particle lubrication and the decrease in the coefficient of friction. Also, it is confirmed that the more the particles are, the less the coefficient of friction is due to particle lubrication. For each experimental condition, the coefficient of friction is measured and compared. Moreover, the contact surface of the specimen is analyzed using an electron microscope, and a profilometer is used to measure the surface roughness of the specimen before and after the test. The reciprocation friction and wear characteristics of WC and Zr with phosphor-containing liquid are evaluated by analyzing the experimental results.

Friction and wear studies of silicon in sliding contact with thin-film magnetic rigid disks

1993 ◽  
Vol 8 (7) ◽  
pp. 1611-1628 ◽  
Author(s):  
Bharat Bhushan ◽  
Sreekanth Venkatesan
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Coefficient Of Friction ◽  
Amorphous Carbon ◽  
Friction And Wear ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Carbon Transfer ◽  
Zn Ferrite ◽  
The Coefficient Of Friction

Silicon is an attractive material for the construction of read/write head sliders in magnetic recording applications from the viewpoints of ease of miniaturization and low fabrication cost. In the present investigation we have studied the friction and wear behavior of single-crystal, polycrystalline, ion-implanted, thermally oxidized (wet and dry), and plasma-enhanced chemical vapor deposition (PECVD) oxide-coated silicon pins while sliding against lubricated and unlubricated thin-film disks. For comparison, tests have also been conducted with Al2O3–TiC and Mn–Zn ferrite pins which are currently used as slider materials. With single-crystal silicon the rise in the coefficient of friction with sliding cycles is faster compared to Al2O3–TiC and Mn–Zn ferrite pins. In each case, the rise in friction is associated with the burnishing of the disk surface and transfer of amorphous carbon and lubricant (in the case of lubricated disks) from the disk to the pin. Thermally oxidized (under dry oxygen conditions) single-crystal silicon and PECVD oxide-coated single-crystal silicon exhibit excellent tribological characteristics while sliding against lubricated disks, and we believe this is attributable to the chemical passivity of the oxide coating. In dry nitrogen, the coefficient of friction for single-crystal silicon sliding against lubricated disks behaves differently than in air, decreasing from an initial value of 0.2 to less than 0.05 within 5000 cycles of sliding. We believe that silicon/thin-film disk interface friction and wear is governed by the uniformity and tenacity of the amorphous carbon transfer film and oxygen-enhanced fracture of silicon.

scholarly journals Sintered Hydroxyapatite Ceramic for Wear Studies

1978 ◽  
Vol 57 (7-8) ◽  
pp. 777-783 ◽  
Author(s):  
Hillar M. Rootare ◽  
John M. Powers ◽  
Robert G. Craig
Keyword(s):  
Coefficient Of Friction ◽  
Tricalcium Phosphate ◽  
Friction And Wear ◽  
Tangential Force ◽  
Hydroxyapatite Ceramic ◽  
Track Width ◽  
Failure Data ◽  
Surface Failure ◽  
Human Enamel ◽  
The Coefficient Of Friction

A sintered hydroxyapatite (HAP) ceramic for use in wear studies was prepared from a commerical tricalcium phosphate. The sintered HAP had physical properties close to those of human enamel. The coefficient of friction and wear of the sintered HAP ceramic as characterized by tangential force, track width, and surface failure data, approximated those of human enamel.

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

2018 ◽  
Vol 20 (17) ◽  
pp. 12027-12036 ◽  
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.

scholarly journals The Effect of Surface Texture on Lubricated Fretting

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4886
Author(s):  
Agnieszka Lenart ◽  
Pawel Pawlus ◽  
Andrzej Dzierwa ◽  
Slawomir Wos ◽  
Rafal Reizer
Keyword(s):  
Coefficient Of Friction ◽  
Surface Texture ◽  
Friction And Wear ◽  
Normal Load ◽  
Disc Surface ◽  
The Coefficient Of Friction ◽  
42Crmo4 Steel ◽  
Ball Diameter ◽  
Steel Balls ◽  
Effect Of Surface

Experiments were conducted using an Optimol SRV5 tester in lubricated friction conditions. Steel balls from 100Cr6 material of 60 HRC hardness were placed in contact with 42CrMo4 steel discs of 47 HRC hardness and diversified surface textures. Tests were carried out at a 25–40% relative humidity. The ball diameter was 10 mm, the amplitude of oscillations was set to 0.1 mm, and the frequency was set to 80 Hz. Tests were performed at smaller (45 N) and higher (100 N) normal loads and at smaller (30 °C) and higher (90 °C) temperatures. During each test, the normal load and temperature were kept constant. We found that the disc surface texture had significant effects on the friction and wear under lubricated conditions. When a lower normal load was applied, the coefficient of friction and wear volumes were smaller for bigger disc surface heights. However, for a larger normal load a higher roughness corresponded to a larger coefficient of friction.

scholarly journals Experimental Evaluation of Oxide Nanoparticles as Friction and Wear Improvement Additives in Motor Oil

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Nicholaos G. Demas ◽  
Robert A. Erck ◽  
Cinta Lorenzo-Martin ◽  
Oyelayo O. Ajayi ◽  
George R. Fenske
Keyword(s):  
Laboratory Test ◽  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Oxide Nanoparticles ◽  
Test Machine ◽  
Motor Oil ◽  
Test Configuration ◽  
Test Conditions ◽  
Contact Configuration ◽  
The Coefficient Of Friction

The effect of two nanoparticle oxides on friction and wear was studied under laboratory test conditions using a reciprocating test machine and two test configurations. The addition of these nanoparticles in base stock oil under certain conditions reduced the coefficient of friction and improved wear, but that depended on the test configuration. Examination of the rubbed surfaces showed the pronounced formation of a tribofilm in some cases, while polishing on the surface was also observed in other cases. Contact configuration is important when oxide nanoparticles are being evaluated and the conclusions about their efficacy can be vastly different.

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