• Title/Summary/Keyword: 공기공동 공명

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FE Analysis for Fundamental Air-cavity Resonant Frequency of Tire (타이어의 첫 번째 공기공동 공명에 관한 유한요소해석)

  • Kim, Yong-Woo;Bang, Sung-Huyn
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.7
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    • pp.685-692
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    • 2009
  • Vehicle interior noise is the results of numerous sources of excitation. One source involving tire pavement interaction is the tire cavity resonance and the forcing it provides to the vehicle spindle. Using a simplified model for the tire acoustic cavity system only, we formulated finite element equation to predict the fundamental acoustic cavity resonant characteristics inside tire-wheel assembly of undeformed and deformed tire. Combining the finite element analysis with experimental verification, we explained the acoustic characteristics theoretically. Especially, we have shown that the difference between the first two resonant frequencies increases as the deformation of deformed tire increases.

FE Analysis for Fundamental Air-Cavity Resonant Frequency of Tire (타이어의 첫 번째 공기공동 공명에 관한 유한요소해석)

  • Kim, Yong-Woo;Bang, Sung-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.551-556
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    • 2009
  • Vehicle interior noise is the results of numerous sources of excitation. One source involving tire pavement interaction is the tire cavity resonance and the forcing it provides to the vehicle spindle. Using a simplified model for the tire acoustic cavity system only, we formulated finite element equation to predict the fundamental acoustic cavity resonant characteristics inside tire-wheel assembly of undeformed and deformed tire. Combining the finite element analysis with experimental verification, we explained the acoustic characteristics theoretically. Especially, we have shown that the difference between the first two resonant frequencies increases as the deformation of tire due to vertical load increases.

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Experiments on Temperature Effect on Air Cavity Resonance and Tire's Vibration Characteristics of a Radial Tire (온도 변화가 승용차용 레이디얼 타이어의 공기공동 공명 및 타이어의 진동특성에 미치는 영향에 관한 실험)

  • Kim, Yong-Woo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.3
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    • pp.102-110
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    • 2008
  • It is well known that the acoustic cavity inside the tire-wheel assembly contributes to vehicle interior noise and ride comfort. In this paper, we performed acoustic and structural modal testings by varying the temperature ranging from $20^{\circ}\;to\;45^{\circ}C$ to investigate the effects of temperature on acoustic cavity resonance and structural vibration characteristics for unloaded and loaded tires. The testing has given us some findings, which are reported in this paper.

Experiments on the Influence of the Air Cavity Resonance on the Structural Vibration Modes in Radial Tire (승용차용 레이디얼 타이어에서 공기공동진동형이 구조진동형에 미치는 영향에 관한 실험)

  • Kim, Yong-Woo;Jeong, Kyoung-Shin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.6
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    • pp.44-49
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    • 2007
  • It is well known that the acoustic cavity inside the tire-wheel assembly contributes to vehicle interior noise. In this paper, we have performed acoustic and structural modal testings to investigate the influences of the acoustic cavity resonance on structural vibration characteristics for the tire in free-suspension and for the loaded tire. The testings have given us some findings, which are reported in this paper.

공동주택 세대간 생활소음 저감을 위한 소음기 개발

  • Lee, K.H.;Kwon, B.H.;Lee, J.H.;Oh, J.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1450-1454
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    • 2007
  • 주상복합형 주거공간에 각 실간 Cross Talking에 의한 소음을 저감시키고 실내기의 공기조화로 발생하는 팬의 소음을 저감 시키기 위하여 소음 환기 장치를 개발 하였다. 공명형과 팽창형의 특성을 적용한 복합적 소음기로 저감주파수 대역에 따른 설계가 가능하며 이 소음기 성능시험 결과 특정 주파수 대역에서 20dB이상의 삽입손실치가 발생하고, 삽입에 의한 압력손실 2mmAq 이하가 됨을 확인하였다. 본 개발품의 특성은 구조가 간단하고 분해조립이 가능하여 설치 및 유지보수가 용이한 제품이다.

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3-D Vibration Modes of the Tire in Ground Contact and Its Effects on Wheel and Axle When Excited by a Vertical Impact at the Center of Contact Patch (접지면 중앙에서 수직방향 가진에 의한 타이어의 3차원 진동모드가 휠/축에 미치는 영향)

  • Kim, Yong-Woo;Nam, Jin-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.4
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    • pp.325-332
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    • 2004
  • Tire vibration modes are known to play a key role in vehicle ride and comfort characteristics. Inputs to the tire such as impacts, rough road surface, tire nonuniformities, and tread patterns can potentially excite tire vibration. In this study, experimental modal analysis on the tire with ground contact are performed by impacting the tire in the radial direction at the center of contact patch. To investigate which modes of tire influence the vibration of wheel and axle when the tire is in contact with ground, the vibration characteristics such as frequency response functions, natural frequencies and their mode shapes from tire to wheel/axle are examined.

3-D Vibration Modes of the Tire in Ground Contact and Its Effects on Axle When Excited by a 3-D Impact at the Center of Contact Patch (접지면 중앙에서 3차원 방향의 충격 가진에 의한 타이어의 3차원 진동형이 축에 미치는 영향)

  • 김용우;남진영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.6
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    • pp.171-182
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    • 2003
  • Tire vibration modes are known to play a key role in vehicle ride and comfort characteristics. Inputs to the tire such as impacts, rough road surface, tire nonuniformities, and tread patterns can potentially excite tire vibration. In this study, experimental modal analysis on the tire in ground contact are performed by a 3-D impact at the center of contact patch to investigate which modes of tire influence the vibration of wheel and axle. Through the experiment, the vibration transmission properties from tire to axle are examined. And we have compared the influential tire modes when the tire is excited by a vertical impact with those when excited by the 3-D impact. Additionally, the modes of ground contact tire are compared with those of the suspended tire.

A experimental Feasibility of Magnetic Resonance Based Monitoring Method for Underground Environment (지하 환경 감시를 위한 자기공명 기반 모니터링 방법의 타당성 연구)

  • Ryu, Dong-Woo;Lee, Ki-Song;Kim, Eun-Hee;Yum, Byung-Woo
    • Tunnel and Underground Space
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    • v.28 no.6
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    • pp.596-608
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    • 2018
  • As urban infrastructure is aging, the possibility of accidents due to the failures or breakdowns of infrastructure increases. Especially, aging underground infrastructures like sewer pipes, waterworks, and subway have a potential to cause an urban ground sink. Urban ground sink is defined just as a local and erratic collapse occurred by underground cavity due to soil erosion or soil loss, which is separated from a sinkhole in soluble bedrock such as limestone. The conventional measurements such as differential settlement gauge, inclinometer or earth pressure gauge have a shortcoming just to provide point measurements with short coverage. Therefore, these methods are not adequate for monitoring of an erratic subsidence caused by underground cavity due to soil erosion or soil loss which occurring at unspecified time and location. Therefore, an alternative technology is required to detect a change of underground physical condition in real time. In this study, the feasibility of a novel magnetic resonance based monitoring method is investigated through laboratory tests, where the changes of path loss (S21) were measured under various testing conditions: media including air, water, and soil, resonant frequency, impedance, and distances between transmitter (TX) and receiver (RX). Theoretically, the transfer characteristic of magnetic field is known to be independent of the density of the medium. However, the results of the test showed the meaningful differences in the path loss (S21) under the different conditions of medium. And it is found that the reflection coefficient showed the more distinct differences over the testing conditions than the path loss. In particular, input reflection coefficient (S11) is more distinguishable than output reflection coefficient (S22).