• Title/Summary/Keyword: Noise and Vibration Characteristics

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Vehicle Noise Status and Characteristics (자동차소음 현황과 특성)

  • 강대준;정일록;김종민;서웅열;박준철;최용호
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.616-622
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    • 2001
  • The road traffic noise becomes aggravated due to the rapid increase of motor vehicles. It has a great effect on the dwelling environment. Therefore we investigate the characteristics and sources of the motor vehicle noise through grasping the status of the motor vehicle noise. Traffic noise results from the collective contribution of the noise produced by individual motor vehicles. The motor vehicle noise varies enormously depending upon its type and mode of operation.

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Tyre/road Noise Status and Characteristics (타이어소음 현황 특성)

  • 강대준;정일록;장성기;서충열;박준철
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.711-718
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    • 2001
  • The tyre/road noise becomes aggravated due to the rapid increase of motor vehicles. It has a great effect on the dwelling environment. Therefore we investigate the characteristics and sources of the tyre/road noise through grasping the status of the tyre/road noise. Traffic noise results from the collective contribution of the noise produced by individual motor vehicles. The tyre/road noise varies enormously depending upon its type and mode of operation.

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Evaluating the Vibrational Characteristics of Floor Impact Noise in Different Structural Elements of an Apartment House (바닥충격에 의한 공동주택의 바닥, 벽, 천장의 진동 및 소음방사특성 연구)

  • Lee, Byung-Kwon;Jeon, Jin-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.351.2-351
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    • 2002
  • The overall noise reduction was compared in regard to the vibrational characteristics of floor impact noise in a multi story residential building which has several noise reduction treatments. The vibration through its structural elements such as wall, floor and ceiling and sound emitting were investigated for each insulation treatment. It was found that, in case of heavy-weight impact noise, the vibration energy is emitted mostly from ceiling, but for the light-weight impact noise, most of the energy comes through ceiling and walls. (omitted)

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Vibro-acoustic Characteristics of a Cylindrical Shell Type Gearbox Models by Helical Gear Excitation (헬리컬기어 가진에 의한 원통형 기어박스 모델의 진동음향 특성)

  • Park, Chan IL
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.1
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    • pp.36-42
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    • 2017
  • Helical gear excitation is transmitted to a gearbox through the shafts and bearings and the vibration of the gearbox radiates the noise in the air. Therefore gearbox modeling is essential to evaluate the gear noise. This work deals with vibration and acoustic analysis of a cylindrical shell-type gearbox with/without holes excited by helical gears and focuses on the development of the simple gearbox model. To do so, helical gears and bearing forces are calculated. Gearbox with/without holes is modeled by the aluminum end plates and PMMA cylindrical shell body. The vibration mode and the forced harmonic response were calculated by the commercial FE software and the end plate of the gearbox is more contributed to vibration than the body. Acoustic analysis was also conducted by the commercial acoustic software and a cylindrical shell type gearbox with/without holes has the similar vibro-acoustic characteristics.

Development of precision vibration isolation table and study of dynamic characteristics with experiment (정밀 제진대 개발 및 동특성에 관한 실험적 연구)

  • 김인수;김종연;한문성;김영중
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11a
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    • pp.329-334
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    • 2001
  • Recently, the high precision technology can not be developed continuously if we don't have anti vibration technology. Vibration isolation technology using an air spring and laminated robber bearing is widely used because it has excellent vibration isolation characteristics. We developed high precision vibration table with two good element(air spring and LRB) for semiconductor factory. Air Spring is used for isolating the vertical vibration and LRB is used for isolating the horizontal Vibration. As a result, It has D-Class degree in BBR-Criteria. In this paper, we talk about orifice characteristics in the self-damped air spring and design flow of the laminated robber bearing. The orifice characteristics is delicate shade of length and diameter. When we do experimentation to find orifice characteristics, length is fixed and diameter is changed. The orifice diameter is the wider and the air spring stiffness is the softer.

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The source identification of noise & vibration using characteristics of vibro-acoustic transmission (진동-음향 전달특성을 이용한 진동 및 소음원의 규명)

  • Oh, Jae-Eung;Kim, Dong-Sup;Kim, Woo-Taek;Kang, Hyun-Seok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.495-499
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    • 2000
  • The booming noise of a vehicle is usually caused by the vibration of the vehicle's body transmitted from the engine through the mounting system. Thus the engine mounting system must be cautiously designed to reduce the noise. Vector synthesis analysis is performed to predict the booming noise when the characteristic of the engine mounting system is changed., i.e., when magnitudes and phases of vibratory forces after the mounts are altered. To effectively use the method, the concept of 'effectiveness' is introduced to identify the contributions of each vibration sources and transmission paths to interior noise. When the magnitudes and phases of the forces due to the engine vibration are changed, the synthesized interior booming noise level is predicted by the vector synthesis diagram. Thus, the optimum characteristics of the forces are obtained through the simulations of the vector synthesis analysis. It is shown that the vector synthesis method can be used to obtain the optimum design characteristic of the mounting system to control the interior booming noise of a vehicle.

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Study on Noise Reduction of Plasma Display Panel (플라즈마 디스플레이의 소음 저감 연구)

  • Park, Dae-Kyong;Kweon, Hae-Sub;Jang, Dong-Seob
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.693-698
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    • 2002
  • For the evaluation of the plasma display panel (PDP)'s noise, vibration and sound characteristics of fanless PDP are measured and investigated. PDP is a type of two-electrode vacuum tube which operates on the same principle as a household fluorescent light. An inert gas such as argon or neon is injected between two glass plates on which transparent electrodes have been formed, and the glass is illuminated by generating discharge. For this discharge, both high voltage and currents are needed and cause an acoustic noise. We investigated the noise characteristics connected with both a electromagnetic elements from SMPS to panel through X, Y and logic board, and a mechanical elements form panel to case through transfer path which related with vibration and heat. To reduce the noise of PDP, a discharge pulse memory design related with both higher brightness and lower power consumption is important and mechanical characteristics connected with dissipation process of both heat and vibration generated by panel discharge must be investigated.

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Driving Characteristics of SRM with an Auxiliary Fully Pitched Winding

  • Jung, Tae-Uk;Oh, Seok-Gyu;Ahn, Jin-Woo;Hwang, Young-Moon
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.763-767
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    • 1998
  • In this paper, we analyzed the characteristics and source of vibration and acoustic noise in SRM drives. The paper study the reduction technique of those by new SRM which has auxiliary field winding. The operating mechanism and vibration and acoustic noise characteristics is examined. This paper suggests the control strategies of auxiliary field winding in order to reduce vibration and acoustic noise.

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Study on Noise Reduction of DLP Projector (DLP 프로젝터의 소음 저감 연구)

  • 박대경;장동섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.132-137
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    • 2003
  • For the evaluation of acoustic noise of a DLP projector, vibration and sound characteristics of a DLP projector were studied. The acoustic noise of DLP projector could be classified into three categories, that is, the direct noise from a body of rotation, the air-bone noise generated from turbulence or vortex occurred during cooling process and the structural born noise produced by vibrating elements. Cooling fans and color filter wheel which rotates at 9000 rpm are main causes of acoustic noise induced in DLP projector. Since the structure of an optical module in a DLP projector can be excited by the excessive vibration of a color filter wheel, the structural design for anti-vibration should be considered. To make a reduction of overall acoustic noise, the anti-vibration design and the enclosing structure have been studied and applied to a color filter wheel.

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