• Title/Summary/Keyword: Structure-borne noise

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A Study on the Excavation Method Near Fish Farms and Livestock (양만장 및 가축사육시설 인접지역 암굴착공법 검토에 관한 연구)

  • Lim, Dae-Kyu;Shin, Young-Cheol;Jun, Yang-Bae
    • Explosives and Blasting
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    • v.31 no.1
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    • pp.23-32
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    • 2013
  • Construction vibration such as explosive blast, hydraulic breaker, vibratory roller, pile driving noise and so on, injuries in areas around the construction sites. In particular, underwater sound caused by ground vibration is propagation such as structure borne noise. Vibration and underwater sound due to construction activities may cause injury to river, sea or land fish farms near construction sites. The purpose of present study is to measure the sound pressure level and frequency analysis of the underwater noise generated by ground vibration(Blasting, hydraulic crawler drill, hydraulic breaker, vibratory roller). Underwater noise were monitoring by a hydrophone (TC 4013) and recorded, analysis were made using a by software (Prosig).

Improvement of Interior Booming Noise in the Vehicle Using the Structural Dynamic Modification (구조물 동특성 변경을 이용한 실내 부밍 소음 개선)

  • Kim, Young-Ha;Lee, Jae-Woong;Kim, Sung-Gi
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.354-359
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    • 2012
  • Improvement of structure-borne noises in the vehicle compartments has been one of the primary concerns in the development of vehicles. The booming is an annoying low frequency interior noise and vibration in vehicle. But it is difficult to reduce the structure-born booming noise in traditional method - trial and error within the shorten development schedule. So in present, the structure dynamic modification (SDM) method helpful to predict the effect of the local mass, stiffness, and damping is introduced. So in order to reduce the interior booming noise, the SDM was performed, and verified with modal test result. It was shown that the interior booming noise was reduced as predicted.

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A Study of floor impact noise reduction in a steel structure by using the floating floor (Floating floor를 이용한 강구조물의 바닥충격음 저감에 관한 연구)

  • 김현실;김재승;강현주;김봉기;김상렬
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.751-755
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    • 2003
  • In this paper, floor impact noise reduction in a steel structure is studied. A mock-up is built by using 6t steel plate, and two identical cabins are made where 25t panel is used to construct wall and ceiling inside the steel structure. Various floating floor systems are tested for which normalized impact noise is measured according to ISO 140-7. In addition, floor SBN(Structure-borne Noise) and floor damping are measured to study the effect of floating floor. structure. It is shown that VL(Visco-elastic Layer) is more effective when hard plates are added above the VL.

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Prediction of Isolation Performance of Multi-Layered Sound Barrier System Using the Sound Pressure Radiated by Point Impact (점가진력에 의해 방사된 읍압을 이용한 다중 적층 흡차음 시스템의 차음 성능 예측)

  • 김정수;신재성;강연준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1081-1085
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    • 2002
  • A modeling is developed to predict the isolation performance of sound barrier systems under the sound pressure radiated from excited by point impact. The predicted results are compared with the measured results obtained by using APAMAT II. This instrument provides a combination of structure-borne noise and air-borne noise, which corresponds to rolling noise, by applying the excitation system projected steel balls against the steel sheet.

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Road Noise Prediction Based on Frequency Response Function of Tire Utilizing Cleat Excitation Method (크리트 가진법을 이용한 타이어특성에 따른 로드노이즈 예측 연구)

  • Park, Jong-Ho;Hwang, Sung-Wook;Lee, Sang-Kwon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.8
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    • pp.720-728
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    • 2012
  • It is important for identification of noise and vibration problem of tire to consider influence of interaction between road and tire. A quantification of road noise is a challenging issue in vehicle NVH due to extremely complicated transfer paths of road noise as well as the difficulty in an experimental identification of input force from tire-road interaction. A noise caused by tire is divided into road noise(structure-borne noise) and pattern noise(air-borne noise). Pattern noise is caused by pattern shape of tire, which has larger than 500 Hz, but road noise is generated by the interactions between a tire and a vehicle body. In this paper, we define the quantitative analysis for road noise caused by interactions between tire and road parameters. For the identification of road noise, the chassis dynamometer that is equipped $10mm{\times}10mm $ square cleat in the semi-anechoic chamber is used, and the tire spindle forces are measured by load cell. The vibro-acoustic transfer function between ear position and wheel center was measured by the vibro-acoustic reciprocity method. In this study three tires with different type of mechanical are used for the experiment work.

A Technique to Identify the Structure Borne Noise Sources Related to Structure Vibration Using Response Signals (응답측정을 통한 구조물의 진동과 관련된 구조적 소음원 규명)

  • 이재갑;여승동;방정환
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1994.10a
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    • pp.160-164
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    • 1994
  • 본 논문에서는 구조물의 진동으로 야기되는 소음원을 규명하기 위해 구조물 동작중의 응답신호를 측정한다. 먼저 응답 신호벡터에서 스펙트럼행렬을 구성하여 특이치 분리법을 수행한다. 특이치의 정보로 구조물의 응답에 영향을 미치는, 서로 독립적으로 작용하는 주 가진원을 파악한다. 간단한 구조물에 대해, 본 논문에서 적용된 기법의 유용성 및 물리적 성질을 검토한 후, 자동차 파워트레인이 구조 진동이 실내 소음에 미치는 구조적 소음을 실험을 통해 규명한다.

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The Evaluation of the Road Noise of the Automotive Tire by Subjective Test (주관적인 시험에 의한 자동차 타이어 도로소음 평가)

  • Lee, Tae-Keun;Kim, Byoung-Sam;Cho, Tae-Jea
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.6
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    • pp.91-96
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    • 2008
  • As a remarkable reduction of the vehicle noise, the important of tire noise which is generated from the vehicle and the necessity of the research for the noise reduction is being emphasized. In this study, the road noise which is excited by the interaction between tire and road has been studied. The subjective test(feeling test) according to SAE J1060 rating scale is applied to the evaluation of the road noise. The combination of the several tires and vehicles are made to consider the effect of the vehicle suspension and the tire structure for road noise. The vehicles with 3-different suspension system are applied to road noise test and the eight kinds of tires are selected. As the results, the effects of the vehicle suspension and tire structure which affects on road noise are investigated.

Prediction of Interior Noise Caused by Tire Based on Sound Intensity and Acoustic Source Quantification (공기 기인 소음 분석과 음향 인텐시티법을 이용한 타이어에 의한 실내 소음 예측)

  • Shin, Kwang-Soo;Lee, Sang-Kwon;Hwang, Sung-Uk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.4
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    • pp.315-323
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    • 2013
  • Tire noise is divided into a road noise(structure-borne noise) and a pattern noise(air-borne noise). Whilst the road noise is caused by the structural vibration of the components on the transfer path from tire to car body, the pattern noise is generated by the air-pumping between tire and road. In this paper, a practical method to estimate the pattern noise inside a passenger car is proposed. The method is developed based on the sound intensity and airborne source quantification. Sound intensity is used for identifying the noise sources of tire. Airborne source quantification is used for estimating the sound pressure level generated by each noise source of a tire. In order to apply the airborne source quantification to the estimation of the sound pressure, the volume velocity of each source should be obtained. It is obtained by using metrics inverse method. The proposed method is successfully applied to the evaluation of the interior noises generated by four types of tires with different pattern each other.

Study on the Effect of Vibration Reduction Characteristics of Floors on the Inside Running Noise in Railway Vehicles (전동차 바닥구조의 진동절연특성이 실내소음에 미치는 영향)

  • Woo, Kwan-Je
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.908-912
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    • 2008
  • Structure-borne noise is known to dominate internal running noise levels in open field. In this paper vibration isolation characteristics of floors are investigated to see their effect on the internal running noise. By using the analysis and test results of test specimen of small size, internal running noise level of complete train is estimated. Analysis results show that soft rubber as a vibration isolator has the most favorable effect on the inside running noise.

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