scholarly journals Local coating of curved rails by using low friction material for squeal noise reduction

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098065
Author(s):  
Jae Chul Kim ◽  
Hee-Min Noh ◽  
Yang Soo Yun
Keyword(s):  
Friction Coefficient ◽  
Friction Material ◽  
Low Friction ◽  
Before And After ◽  
The Coefficient Of Friction ◽  
Roller Rig ◽  
Comparison Of The Results ◽  
Curve Squeal ◽  
Squeal Noise ◽  
Contact Position

Curve squeal noise is one of the most prominent noises among railway noises. High levels of noise are generated when a train passes through curved sections, resulting in several complaints from the residents and vehicle passengers. To mitigate this problem, the squeal noise was attempted to be mitigated by laser cladding the composite material on the head of the rail. First, the effect of the negative gradient of the coefficient of friction on the squeal noise was theoretically examined. A simple model analysis indicated that the vibration of the wheel increased rapidly when the vibration system involved instability characteristics. In addition, the change in the friction coefficient owing to the local coating of the rail with a low friction material was investigated using a roller rig test equipment. The results demonstrated that the negative friction coefficient did not occur when the contact position between the wheel and rail was locally coated. Furthermore, the effect of the low friction local coating on the squeal noise in the curve section was examined in operational rails. The comparison of the results obtained before and after the local coating confirmed that the local coating of the rail can effectively reduce the squeal noise.

The Study of Disc Brake Noise on Three Different Types of Friction Materials

2014 ◽  
Vol 663 ◽  
pp. 113-118 ◽  
Author(s):  
Ahmad Razimi Mat Lazim ◽  
Abd Rahim Abu Bakar ◽  
Mohamed Kchaou
Keyword(s):  
Friction Material ◽  
Pressure Level ◽  
Material Composition ◽  
Disc Brake ◽  
The Road ◽  
Before And After ◽  
Squeal Noise ◽  
The Relationship ◽  
Brake Noise ◽  
Brake Friction Material

This work investigates the effect of road grit particles and material compositions on disc brake squeal noise. Three different Non Asbestos Organic (NAO) brake pad samples and road particles with a size range between 400 μm to 500 μm are used in the squeal experiment. The relationship between the existence of road particle with the noise occurrence were studied through the change in pressure level, friction coefficient (CoF), sound pressure level (SPL) and material composition. The material compositions were analyzed before and after squealing condition using energy dispersive X-ray analysis (EDX). Result has shown the road particles contribute to the emission of squeal noise and the increasing of some material composition of brake friction material components.

Understanding Friction Behavior in Automatic Transmission Fluid LVFA Test: A New Positive Curve Parameter to Friction Coefficient Ratio Index Evaluation

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Hongyuan Zhao ◽  
Ardian Morina ◽  
Anne Neville ◽  
John Durham ◽  
Richard Vickerman
Keyword(s):  
Friction Coefficient ◽  
Automatic Transmission ◽  
Friction Material ◽  
Material Surface ◽  
Test Machine ◽  
Oil Absorption ◽  
Friction Behavior ◽  
Index Evaluation ◽  
The Coefficient Of Friction ◽  
Friction Performance

The frictional characteristics of some basic additive systems used in automatic transmission fluids (ATFs) were assessed using a variable speed friction test machine. The test evaluates the coefficient of friction in unidirectional sliding contact over a range of speeds, loads, and temperatures. Tests were performed on a steel-versus-clutch friction material tribocouple, mainly to establish the link between the lubricant/surface interactions and additive system performance. A new parameter that measures the positive μ-v curve slope speed range was applied, together with friction coefficient ratio index, to show the antishudder property. It is suggested that this is a good complimentary method to the friction coefficient ratio index evaluation. Lubricant formulation is important to the overall friction performance. Both friction modifiers and detergents are shown to be important to the ATF antishudder performance. Oil absorption ability of the post-test friction material surface is proposed to be an important parameter to indicate the antishudder durability in the test. The detergent and antiwear agents are also suggested to be responsible for the decreased oil absorption and pore plugging of the friction material surface.

Analysis of sliding friction of WC-Co composite on particleboard

2020 ◽  
Vol 111 ◽  
pp. 60-67
Author(s):  
Jacek Wilkowski ◽  
Marek Barlak ◽  
Radosław Jałocha ◽  
Zbigniew Werner ◽  
Alicja Auriga
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Sliding Friction ◽  
Roughness Parameter ◽  
Average Increase ◽  
Average Coefficient ◽  
Before And After ◽  
The Coefficient Of Friction ◽  
Nano Size

Analysis of sliding friction of WC-Co composite on particleboard. The paper presents the analysis of the coefficient of friction at the contact area between WC-Co composite and particleboard. The four types of WC-Co composite in the form of milling indexable knives for wood materials machining were tested. The tests were carried out on a linear reciprocating tribotester (pin-on-flat), where the sample was the clearance surface of WC-Co indexable knives and the counter-sample was made of three-layer particleboard. Before and after tribological tests, the surface roughness of tested knives was measured. The highest values of friction coefficient were obtained for the type UMG04 of cemented carbide - with nano size of WC grains and the lowest content of cobalt. The average coefficient of friction for selected types of WC-Co correlated with the average increase in surface roughness (the roughness parameter Ry).

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