• 한국정밀공학회지
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• 제28권4호
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• pp.427-435
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• 2011

This paper deals with the measurement and analysis of the squeal noise according to the curvature of rail. The squeal noise is generated by the friction between the railway with curve and the wheel. The squeal noise is a big problem in Busan Metro Line 3. If the developing panel type ANC(Active Noise Control) system which is attached to the floor can reduce 5 dB in below 500 Hz, the sound pressure level of the whole band pass can be reduced about 4-4.8 dB in squeal noise above the curvature of R400. Curve squeal noise is the intense high frequency tonal that can occur when a railway vehicle transverses a curve. The frequency range is from around 500 to almost 20,000 Hz, with noise levels up to about 15 dB in curve.

• 한국정밀공학회지
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• 제28권5호
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• pp.572-577
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• 2011

Curve squealing of inter-city railway vehicle is a noise with high acoustic pressure and rather narrow frequency spectra. This noise turns out to be very annoying for the people living in the neighborhood of locations and the passenger in railway vehicle where this phenomenon occurs. Squealing is caused by a self-exited stick-slip oscillation in the wheel-rail contact. Curve squeal noise of railway vehicles that passed by a factor of the speed limit, so to overcome in order to improve running performance is one of the largest technology. In the present paper, characteristic of squeal noise behavior at the Hanvit-200 tilting train test-site. Curve squealing of railway wheels/rail contact occurs in R400~ R800 curves with a frequency range of about 4~11 kHz. If the curve is less than the radius of wheel frail contact due to |left-right| noise level difference (dBA) shows a significant effect of squeal noise were more likely.

• 한국소음진동공학회논문집
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• 제22권2호
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• pp.163-169
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• 2012

The brake squeal propensity associated with friction curve is investigated by using the hybrid finite element(FE)-analytical model. The modal analysis of an actual disc and pad is conducted by FE method. Also, the modeling for the accurate contact and disc rotation is analytically achieved. The eigenvalue analysis for the hybrid model provided the squeal dependency on the friction curve. Particularly, some pad modes and the disc torsion mode are shown to be sensitive for the friction curve.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.520-526
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• 2016

Squeal noise is a typical brake noise that is annoying to both passengers and pedestrians. Its frequency range is fairly wide from 1 kHz to 18 kHz, which can be distressful to people. The brake squeal noise occurs due to various mechanisms, such as the mode coupling of the brake system, self-excited vibration, unstable wear, and others. In this study, several parameters involved in the generation of a squeal noise are investigated experimentally by using a brake noise dynamometer. The speed, caliper pressure, torque, and friction coefficient are measured as functions of time on the dynamometer. The contact pressure and temperature distributions of the disc and the pad are also measured by using a thermal imaging camera and a pressure mapping system. As a result of the simultaneous measurement of the friction coefficient and squeal amplitude as functions of the velocity, it is found that the onset of the squeal may be predicted from the ${\mu}-v$ curve. It is also found that a non-uniform contact pressure causes instability and, in turn, a squeal. Based on the analysis results, design modifications of the pad are suggested for improved noise characteristics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.29-32
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• 2005

This paper presents experimental analysis of a friction-driven wheel that is responsible for wheel squeal. Squeal noise generating mechanism and environment of train u heels has been tried to reproduce under laboratory condition. Scale down size rail and wheel are made and influential parameters to squeal noise are measured, e. g. frictional force, pressure between rail and wheel, creep speed of rail. Negative damping characteristic curve are calculated currently. Necessary relating computational analysis is also carried on.

• 한국소음진동공학회논문집
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• 제23권8호
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• pp.717-724
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• 2013

The present study provides the numerical results in association with caliper stiffness and friction curve. From the numerical results, it is concluded that the pad vibration modes with dominant displacement in rotation direction is sensitive in the flutter instability. Particularly, the pad rigid mode is shown to become the squeal mode when the caliper stiffness is introduced in brake squeal model. Therefore, the caliper contact stiffness between the pad and caliper is expected to contribute to the squeal modes of the brake pad.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.174-177
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• 2007

In this paper the noise characteristics of metro train is investigated experimentally. It is primarily aimed at observing the squealing noise radiation of each wheel when the vehicle pass the curve sections. This will be used to understand the noise excitation mechanism at the contact area between squealing wheels and rails which induce squeal noise at curve sections. To identify the related key parameters and boundary conditions on-board monitorings of the noise, vibration of the wheel and bogie and displacement behaviour of the wheels and rails have been done. In this paper only noise measurement and results are discussed. From spectrogramms squeal noise due to creepage and noise due to flange contact of the wheels could be identified. At the moment of the curve passing the highest squeal levels are found on the front inner wheel. However since curve noise depends on variable factors more analyses will be followed to identify the squealing wheels and the noise excitation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1187-1190
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• 2009

CURVE SQUEAL NOISE IS THE INTENSE HIGH FREQUENCY TONAL THAT CAN OCCUR WHEN A RAILWAY VEHICLE TRAVERSES A CURVE OR A SWITCH. THE HIGH NOISE LEVEL CAUSES ANNOYANCE FOR PEOPLE WHO LIVE IN THE NEIGHBOURHOOD OF THE SQUEALING RAILWAY TRACK AS WELL AS FOR THE PASSENGERS IN CARS WITH CURVES. THIS PAPER EXAMINES THE SPECTRAL SOUND DISTRIBUTION IN CURVES FOR KTX TRAIN. THE FREQUENCY RANGE IS FROM AROUND 4,000 TO ALMOST 16,000Hz, WITH NOISE LEVELS UP TO 92dB IN CURVE R400.

• 한국소음진동공학회논문집
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• 제25권5호
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• pp.352-360
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• 2015

Squeal noise is a harsh, high-pitched sound that occurs when railways are running at sharp curve tracks. The cause of squeal noise is known to be the transient lateral traction force between wheel and rail. Field measurements are too difficult to control the parameters. Thus, the scaled test rig should have been made in order to investigate the generating mechanism of squeal noise. The unique feature of our test rig, HSTR(Hongik Squeal Testing Rig), is that DOFs of its wheelset are as close to as those of the real railway. The attack angle and running speed of the rail roller are controlled in real time for simulating a transient characteristic of driving curve. The environment conditions, such as given axle load, running speed, and wheel's yaw angle have been identified for generating squeal noise and the squeal noise itself has been measured. The relation between wheel creepage and creep force in lateral direction and the criteria for squeal noise have been investigated, which results has been verified by finite element method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.362-367
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• 2010

This paper deals with the correlation between the interior noise and the floor vibration of the train from rolling, impulse and friction in Busan Metro line 3. The correlation is verified by sound and vibration measurement causing friction between the railway and the wheel. If ANC(Active Noise Control) system can reduce 5 dB in below 500 Hz, the sound pressure level of the whole band pass can be reduced about 1.8-4.8 dB in squeal noise. Curve squeal noise is the intense high frequency tonal that can occur when a railway vehicle transverses a curve. The frequency range is from around 500 to almost 20,000 Hz, with noise levels up to about 15 dB in curve.