• Title/Summary/Keyword: Squeal

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An Experimental Study of Squeal Noise Characteristics for Railway Using a Scale Model Test Rig (축소 모델 실험장치를 이용한 철도 스킬소음의 특성에 대한 실험적 연구)

  • Kim, Jiyong;Hwang, Donghyeon;Lee, Junheon;Kim, Kwanju;Kim, Jaechul
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.5
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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.

Squeal Noise Analysis and Reduction of Drum Brake Using Component Mode Synthesis (구분모드합성에 의한 드럼 브레이크 스퀼 소음 해석 및 저감)

  • Kim, Jin-Ho;Bae, Byung-Ju;Lee, Shi-Bok;Kim, Tae-Jong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.1 s.94
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    • pp.72-80
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    • 2005
  • Recent studies have dealt with brake squeal in terms of the coupled vibration of brake component parts. In this paper, we assemble the mode models derived from FE analysis of the individual components of the drum brake system into the system model by considering the friction interaction of the lining and drum at the interface. The validity of the component models are backed up by the experimental confirmation work. By scrutinizing the real parts of the complex eigen-values of the system, the unstable modes, which may be strong candidate sources of squeal noise, are identified. Mode participation factors are calculated to examine the modal coupling mechanism. The model predictions for the unstable frequencies pointed well the actual squeal noise frequencies measured through field test. Sensitivity analysis is also performed to identify parametric dependency trend of the unstable modes, which would indicate the direction for the squeal noise reduction design. Finally, reduction of the squeal noise tendency through shape modification is tried.

The study on the influence of contact pressure distribution on brake squeal analysis (브레이크 스퀼 해석에서 접촉압력분포의 영향에 관한 연구)

  • Lee, Ho-Gun;Son, Min-Hyuk;Seo, Young-Uk;Boo, Kwang-Seok;Kim, Heung-Seob
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1120-1124
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    • 2007
  • Recently in the automotive brake industry brake squeal noise has become one of the top automotive quality warranty issues. The contact pressure is used to predict friction coupling in the brake squeal analysis. The formulation of friction coupling has performed by nonlinear static analysis prior to the complex eigenvalue analysis. This paper proposes a validation methodology of squeal analysis using modal testing and contact analysis and examines the effect of predicted contact pressure that leads to the discrepancy between unstable complex mode and squeal frequency. This studies compose a three step validation process : examining the modal characteristics of component and assembly loaded contact pressure using modal testing and FEM analysis and verifying the contact pressure distribution using nonlinear static analysis and experiment. Finally, the unstable modes from complex eigenvalue analysis and realistic squeal frequency from the noise dynamometer are investigated.

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Squeal Analysis of Disc Brake Using Analytical-FE Squeal Model (스퀼융합모델을 이용한 디스크 브레이크 스퀼 소음 연구)

  • Kang, Jaeyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.11
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    • pp.6406-6411
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    • 2014
  • This paper presents the analytical-FE (finite element) squeal model, which can provide the efficient simulation time and accuracy. The system geometry and the extraction of the vibration modes were constructed using the finite element method. Instead, the friction contact model was derived from theoretical contact kinematics of the rotating disc and the stationary pads. This modeling procedure was incorporated into the perturbed equations of motion based on the finite elements of the system. Throughout the analytical-FE squeal model, the accuracy of linear stability analysis and the simulation time of FE squeal analysis were improved. In addition, the sensitivity of contact stiffness on brake squeal and the mode-coupling mechanism were provided by the system parameter study.

Experimental Study for the Reduction of Wet-brake Squeal Noise in a Forklift (지게차용 습식 브레이크의 스퀼소음 저감에 관한 실험적 연구)

  • Kim, Tae-Jong;Koo, Ja-Ham;Jeong, Weui-Bong;Kim, Young-Hyun;Joo, Won-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.12
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    • pp.1147-1152
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    • 2010
  • The wet brakes used in an industrial forklift often produce noise on braking. Elimination or reduction of this squeal noise is an important task for the improvement of comforts. In this paper, a test rig was developed which was possible for testing of brake noise and an experimental measurement on squeal noise was performed. The causes of the brake noise are identified by experimenting how the factors such as automatic transmission fluid, the groove of friction-plate pad and the material of friction-plate pad affect the squeal noise. In order to identify the squeal characteristics, the signal analyses for noise are performed by using frequency spectrums. Experimental results showed that the viscosity of automatic transmission fluid and the groove pattern of friction-plate pad largely affect the reduction of the wet brake squeal noise in an industrial forklift.

A Study on the effect of Driving Speed and Breaking Power on Squeal Noise of Disk Break (주행속도와 제동력의 변화에 의한 디스크 브레이크의 스퀄 소음에 미치는 영향)

  • Kim J.H.;Kim K.H.;Choi M.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.269-270
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    • 2006
  • Brake noise is classified according to frequency territory: judder, groan and squeal. Squeal noise of disk brake is a noise and self excited vibration with frequency of $1{\sim}10Khz$ caused by the friction force between the disk and the pad of the automobile. Passengers in a vehicle feel uncomfortable. It causes unstable characteristic to the brake system when you try to stop the vehicle. Thus this study aims to find in which conditions the vehicles are stable during the braking hour and find ways to decrease a squeal noise and the vibration by measuring various factors including squeal noise and self excited vibration between the pad and disk brake system during the braking hour. From the result the countermeasure for a squeal noise and a vibration decrease is established. Also the analyzed data is found to be useful and can be applied to the actual brake model.

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Analysis of Curve Squeal Noise for Busan Metro Line 3 (부산 도시철도 3호선 차량 곡선부 스퀼소음 특성)

  • Hong, Do-Kwan;Ahn, Chan-Woo;Han, Geun-Jo;Gang, Hyeon-Uk
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.4
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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.

A Study on Squeal Noise Simulation considering the Friction Material Property Changes according to Temperature and Pressure in an Automotive Brake Corner Module (차량용 브레이크 코너 모듈에서 마찰재의 온도와 압력에 따른 물성치 변화를 고려한 스퀼 소음 해석 연구)

  • Cho, Hojoon;Kim, Jeong-Tae;Chae, Ho-Joong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.546-552
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    • 2012
  • This paper is a study on squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material. For this, data of pressure and temperature dependent material properties of lining is achieved by using lining data base and exponential curve fit. Complex eigenvalue analysis is performed for predicting squeal noise frequency and instability and chassis dynamo test is performed for achieving squeal noise frequency, sound pressure level, occurrence temperature & pressure. Initial multi models are composed for considering complex interface conditions such as pad ear-clip, piston-housing and guide pin-torque member. The simulation result of base models is compared with the test result. Squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material is performed and analyzed using multi models. And additional condition is disc material property variation. Entire simulation conditions are combined and analyzed. Finally, this paper proposes direction of the warm squeal noise model.

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Analysis of the Front Disk Brake Squeal Using Kriging Method (크리깅기법을 이용한 전륜 디스크 브레이크 모델의 스퀼 저감 해석)

  • Sim, Hyun-Jin;Park, Sang-Gil;Kim, Heung-Seob;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.10
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    • pp.1042-1048
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    • 2008
  • Disc brake noise is an important customer satisfaction and warranty issue for many manufacturers as indicated by technical literature regarding the subject coming from Motor Company. This research describes results of a study to assess disk brake squeal propensity using finite element methods and optimal technique (Kriging). In this study, finite element analysis has been performed to determine likely modes of brake squeal. This paper deals with friction-induced vibration of disc brake system under contact friction coefficient. A linear, finite element model to represent the floating caliper disc brake system is proposed. The complex eigen-values are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model. In this paper, Kriging from among the meta-modeling techniques is proposed for an optimal design scheme to reduce the brake squeal noise.

Effect of Reducing Squeal Noise at Railway of Curve Section by using the Watering (살수를 이용한 철도곡선구간 스퀼소음 저감효과에 관한 연구)

  • Ji, Hae-Young;Koo, Dong-Hoe;Jeon, Seung-Woo
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2928-2933
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    • 2011
  • The urban railway has been planned not only the subway, but also the elevated railway in Seoul, South Korea. Therefore, it is steadily increasing civil complaints for railway noise passing through that residential district. In this paper, we focused on noise of squeal characteristics induced by interaction between railway vehicle's wheel and rail. Then we selected the point that carried out scattering water droplet to the rail and compared the noise level of the watering test results before and after. Scattering water test results showed that level of the noise reduced intermittently occurring high frequency characteristics of squeal noise as well as overall noise level. In the future, we will apply the sensor to the sprinkling system for noise reduction where the place of existing squeal noise is, and make a suggestion of this solution will be more economical, environmental-friendly, and appropriate to reduce the squeal noise occurred by railway vehicle than others.

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