• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.598-598
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• 2010

와이퍼 작동 중에 발생하는 진동소음 중 1000Hz 이상의 스퀼 소음은 발생 메커니즘이 정확하게 알려지지 않았으며 발생하는 조건도 불규칙하다. 이 스퀼 소음의 발생 빈도 및 주파수를 변경하는 설계를 위하여 스퀼 진동 소음의 발생 메커니즘의 원인분석이 우선적으로 이루어져야 한다. 이 논문에서는 자동차 와이퍼 시스템에서 워셔액을 분사하였을 때 발생하는 스퀼 소음을 측정하고 인자 별로 분석하였다. 스퀼 소음이 발생하는 인자들을 마찰계수와 연관이 있는 인자, 기하학적인 인자, 와이퍼의 운동과 관련된 인자들로 나누어 분석하였다. 실제 와이퍼 시스템을 구현하기 위하여 모터와 원판 지지대 등을 이용하였고, 마이크로폰, 레이저 바이브로미터, 노이즈북, 아르테미스를 이용하여 측정 및 분석하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.536-541
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• 2003

When a rail vehicle transverses tight curves, it often emits an intense, high-pitched squeal. This squeal has always been noticed as one of the most disturbing noise sources of railway systems. At present, w cannot predicted squeal noise that is influenced by a large number of dependent parameters. In this study, we performed structural analysis to find out the frequency of the wheel and measured squeal noise at Seoul subway. We also tested reduction effectiveness of squeal noise through rail lubricator

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.345-352
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• 2017

In this study, squeal noise with respect to pressure variation is measured by a lab-scaled brake dynamometer and estimated by a complex finite element (FE) eigenvalue analysis. From the FE eigenvalue sensitivity analysis, unstable frequencies occur due to a mode-coupling mechanism and are found to change with variation in contact stiffness. In the experiment, squeal frequencies near 1 kHz, 2.5 kHz, 3.5 kHz, and 4 kHz are increased with pressure variation. The sensitivity of squeal modes to contact stiffness variation obtained from the FE analysis is shown to approximate the variation of squeal frequencies under pressure variation in the experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.672-675
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• 2014

• Journal of the Korean Society for Railway
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• v.6 no.3
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• pp.209-214
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• 2003

When a rail vehicle transverses tight curves, it often emits an intense, high-pitched squeal. This squeal has always been noticed as one of the most disturbing noise sources of railway systems. At present, we cannot predict squeal noise that is influenced by a large number of dependent parameters. In this study, we performed structural analysis to find out the frequency of the wheel and measured squeal noise at Seoul subway. We also tested reduction effectiveness of squeal noise through rail lubricator.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.1092-1098
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• 2009

The squeal propensity of an automotive disc brake system is studied in the theoretical and computational manner. The rotating disc is in contact with two stationary pads and the nonlinear friction is engaged on the contact surface. The friction-coupled equations of motion are derived in the finite element(FE) of the actual brake disc and pad. From the general definition of friction force, the rotation and in-plane mode effects can be included properly in the brake squeal model. The eigenvalue sensitivity analysis and the mode shape visualization at squeal frequencies are also conducted for the detailed investigation. It is found that the squeal propensity is strongly influenced by rotation effect and the in-plane mode can be involved in squeal generation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.5
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• pp.374-380
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• 2014

This article proposes a design guideline to reduce squeal noise generated by an automobile wiper blade. In order to explain the squeal noise phenomenon, a source of squeal noise is experimentally investigated using a rotating disk equipment, and then a single-degree-of-freedom stick-slip vibration model is established for a blade tip. Based on analytical results, we discuss a tendency of the squeal noise for various physical parameters.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.12
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• pp.954-961
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• 2014

Brake squeal noise of KTX is very uncomfortable to passengers and workers in stations. A lot of study has been conducted to inquire into the mechanism of the squeal noise. But understanding of the brake squeal noise is still challenging. In this study, we developed a full-scale tester equipped with a KTX mechanical brake unit. And we measured the vibrational characteristics of each component of the brake unit and compared them with frequency response functions of brake squeal noise measured also in the tester. It was found that the brake squeal noise was more closely related to the vibrational characteristics of the brake pads and hangers in friction condition than those of free components.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.253-261
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• 2013

According to the measured results of KTX brake squeal noise in this study, high level brake noise occurred in a wide frequency range, 100~18,000Hz. To identify the sources of the brake squeal noise, unstable vibration modes due to brake disc/pad interaction were analyzed under various conditions by the finite element method. Complex eigenvalues for a brake unit with a disc and four pads were obtained. It was found that the real parts of the complex eigenvalues, that is, unstable vibration modes, were closely related to friction coefficients, pressure on the brake cylinders, elastic moduli of the components, and other conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.445-446
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• 2012