• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.963-963
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• 2008

• 대한기계학회논문집A
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• 제38권12호
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• pp.1351-1358
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• 2014

본 논문은 차량 제동 시 발생하는 소음의 원인을 해석적으로 예측하고, 본 실험실에서 제작한 브레이크 다이나모 메터를 이용하여 실험적으로 검증하였다. 압력 변화에 따른 브레이크 시스템에 대한 주파수 응답 시험 및 유한 요소 해석(FEM)을 실시하여 캘리퍼 및 디스크의 수직 모드(Out-of-plane)의 시스템 주파수를 추적하였다. 이를 제동 시 발생한 스퀼 소음의 주파수와 비교해본 결과 스퀼 주파수는 캘리퍼 및 패드의 변위를 갖는 시스템 모드임을 확인하였다. 또한 유한 요소 해석을 이용한 복소수 고유치 해석 결과 패드의 회전변위를 발생시키는 캘리퍼 모드가 음의 마찰곡선 기울기와 연동하여 불안정하게 됨을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.604-605
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• 2008

Modal participation factor (MPF) is a widely used in a mode-coupling squeal noise problem for finding the most sensitive component over a complex brake system in a vehicle using eigenvectors of sub-components. This methodology requires the problematic total response of system by the unstable squeal noise at a specific frequency as well as eigenvectors of each component belonging to brake system. In this paper, a unit-force response analysis is performed for intact total system to obtain eigenvectors of each component and then such data is directly used for the contribution analysis of a squeal noise problem. Since the eigenvectors of each component induced from virtual unit-excitation is most reliable owing to the intact boundary condition, it can be expected that the corresponding contribution analysis with MPF also provides a trustworthy result.

• 한국기계가공학회지
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• 제14권1호
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• pp.57-62
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• 2015

The wet brakes used on a forklift often produce noise upon engagement. The elimination or reduction of this squeal noise is an important task for the improvement of the comfort of those operating these machines. In this paper, a test rig was developed for the testing of brake noise, and the squeal noise was measured with this apparatus. Automatic transmission fluid and grooves in the material of the friction-plate pad were found to be the main factors causing squeal noise. In order to identify the characteristics of this type of noise, signal analyses of the noise were conducted using different frequency spectra. The experimental results showed that the viscosity of the automatic transmission fluid and the groove pattern on the friction-plate pad largely affected the reduction of the wet brake squeal noise made by an industrial forklift.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.861-864
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• 2005

Brake noise has been one of the most difficult concerns in the automotive industry. Although substantial research has been conducted to predict and eliminate brake noise, there is yet no method to completely suppress brake noise. Furthermore, little effort has been made to improve noise and vibration characteristics of the railway brake system. The amount of sound energy radiated from the railway brake system is much larger than that from the automobile, and it causes discomfort of passengers in the station. In this paper, noise and vibration caused by the braking force of the KTX vehicle have been measured and analysed. Results show that noise level increases abruptly right before a train comes to a complete stop. Furthermore, typical characteristics of the disk brake squeal have been observed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.606-607
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• 2008

Nowadays, noise and vibration phenomena of a disc brake system have been given various names that provide some definitions of sound and vibration emitted such as grind, grunt, moan, squeak, squeal, judder and wire brush. The most common and annoying noise of a disc brake system is squeal noise. It is defined as noise whose frequency content is 1 kHz and higher with excessively high and irrigating sound pressure levels. In this paper, the noise and vibration characteristics of a disc brake system have been investigated to develop the fusion-type friction material, which overcomes the low steel and non-asbestos organic friction materials. For the purpose, both experimental evaluation and complex eigenvalue analysis have been carried out.

• 한국소음진동공학회논문집
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• 제22권12호
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• pp.1206-1212
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• 2012

The brake squeal propensity due to the friction-velocity curve is numerically investigated. The finite element models for the disc and pad are correlated with the modal test. In the friction-engaged system modeling, the friction function is linearized at the equilibrium. The damping term induced by friction-velocity slope is incorporated into the equations of motion. In the complex eigenvalue analysis, it is found that the pad shear mode is very sensitive to the friction curve. The results shows that the squeal propensity of the pad shear mode can be controlled by the design parameters such as pressure and stiffness.

• 대한기계학회논문집A
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• 제32권11호
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• pp.930-936
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• 2008

This paper studies the effect of pad at initial stage and wear during braking on the dynamic contact pressure distribution. Wear is influenced by variable factor (contact pressure, sliding speed, radius, temperature) during dynamic braking and variation in contact pressure distribution. Many researchers have conducted complex eigenvalue analysis considering wear characteristic with Lim and Ashby wear map. The conventional analysis method is assumed the pad has smooth and flat surfaces. The purpose of this paper is to validate that wear rate induced by braking is considered for the precise squeal prediction. After obtaining pad wear from experiment, it is incorporated with FE model of brake system. Finally, the comparisons in fugitive nature of squeal will be carried out between the complex eigenvalue analysis and noise dynamometer experiment.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.41-47
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• 1994

An optimal brake pad must have stable friction, low wear and least amount of squeal. In this study, the friction, wear and squeal behavior of some non-asbestos Kevlar materials have been evaluated experimentally. Four specimens with different formulations and a pin-on-disk machine were used for this study. To determine the role of each component in friction and squeal of a brake pad, statistical correlations have been obtained and discussed. The components tested were : Kevlar, Steel Powder, Barium Sulfate and fillers combined by Resin.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.41-47
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• 2005

This paper deals with a squeal noise in a brake system. It has been proved that the squeal noise is influenced by the angular misalignment of a disk, disk run-out, with the previously experimental study. In this study, a cause of the noise is examined by using FE analysis program(SAMCEF) and numerical analyses with a derived analytical equation of the disk based on the experimental results. The FE analyses and numerical results show that the squeal noise is due to the disk run-out as the experimental results and the frequency component of the noise equals to that of a disk's bending mode arising from the Hopf bifurcation.