• Title/Summary/Keyword: 고체음

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The Development of Shipboard Noise Analysis System using Statistical Energy Analysis(I) (SEA를 이용한 선박소음해석 시스템 개발(I))

  • Hyun-J. Kang;Hyun-S. Kim;Jae-S. Kim;Sung-Y. Han;Young-C. Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.31 no.1
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    • pp.133-141
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    • 1994
  • In this paper, experiences obtained during the development of MASS(Noise Analysis of Ship-board using SEA) are described. The results are summarized as follows. (1) The modelling techniques for ship structure and cabins are suggested. (2) Structureborne and airborne noise for a real ship were measured at sea trial and predicted by NASS. The differences between the two values are acceptably small for the cabins located on higher decks, although problems related with modelling of lower decks and evaluation of radiation efficiency were found.

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Study on the Transmission Loss of Structureborne Noise Using Statistical Energy Analysis (SEA이론을 이용한 고체음 전달해석에 관한 연구)

  • Hyun-Ju Kang;Jae-Seung Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.1
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    • pp.113-122
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    • 1992
  • When predicting shipboard noise levees, the accuracy depends largely on the value of the structureborne noise transmission loss. Although empirical formulars are frequently used because of their simplicities, researches on the analytical methods to estimate the transmission loss of structureborne noise such as wave guide theory and SEA has long bean one of the major topics in shipboard acoustics to overcome the inherent limiations of empirical ones. This paper describes an application of SEA to predict the transmission loss of the structureborne noise of a simple shiplike structural mode1 consisted of 22 flats plates. The result shows trial discrepancies between experimental and theoretical transmission losses are less than 3 dB.

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An Analysis on Structureborne Noise Tranmission Loss of Ship Structure (선체구조의 고체음 전달해석)

  • 강현주;김재승;김현실
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1991.04a
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    • pp.31-39
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    • 1991
  • When predicting shipboard noise levels, the accuracy depends largely on the value of the structureborne noise transmission loss. Although empirical formulars are frequently used because of their simplicities, researches on the analytical methods to estimate the transmission loss of structureborne noise such as wave guide theory and SEA has long been one of the major topics in shipboard acoustics to overcome the inherent limitations of empirical ones. This paper describes an application of SEA to predict the transmission loss of the structurebornenoise of a simple ship-like structural model consisted of 22 flat plates. The result shows that discrepancies between experimental and theoretical transmission losses are less than 3 dB.

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A Study on the Propagation Characteristics of Solid-Borne Sound in Apartment Building (아파트에서 고체음의 부파성상에 관한 연구)

  • 김영완;박병진
    • The Journal of the Acoustical Society of Korea
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    • v.5 no.4
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    • pp.5-15
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    • 1986
  • This pater is a study on the measurement of solid-borne sound propagation in buildings. The purpose of this paper is to present the data needed for comfortable building enevironment. Solid-Borne sound in apartment building was measured at the source of sound and at many receiving locations in building. Dispersion of the sound level was analyzed to understand noises level at different locations. Graphic method as well as polynomial regression techniques were employed. For this experiment, we made use of the TAPPING MACHINE according to the standard rules of ISO as a impulse exciter, and the measurement was carried out after the building has been all completed. Noticeable noise reductions were observed as the distance from the source to the receiving location increases.

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Structure-borne noise in a house generated by the subway operation (지하철 주행에 의한 건물내 고체음)

  • 채수연
    • Journal of the Korean Professional Engineers Association
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    • v.19 no.2
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    • pp.21-25
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    • 1986
  • Structure-borne noise due to forced vibration which is originated from subway operation and transmitted to buildings in order of rail-wood tie-concrete bed-structure-soil-building foundations-members of building results in social problem of environmental pollution. Moreover this becomes a serious problem because of the increment of surface traffic and subway operation made by meeting traffic system in crowded cities. Since subway is constructed along the principal road or through the residential area and as the worst case may be, building foundations is contact with top part of subway structure, it is possible that vibration resonance results in fatal damage of buildings. And, structure-borne vibration noise due to subway operation at late and early hours have the residents suffer from insonmia, restlessness and so on. Therefore, to satisfy the future need concerning the environmental protection, this report deals with the influence of structure-borne vibration noise on the basis of the characteristics of Seoul Subway System.

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Reduction of structure-borne noise from machineries including pumps (펌프류 장비의 고체음 저감에 관한 연구)

  • 김상렬;김현실;김재승;강현주;고성윤
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.510-515
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    • 1998
  • Most of large structures such as ship, airplane, and so on have internal structure home noise sources. The operation of the machineries results in vibration and noise of the structure. Particularly, the vibration of the machineries is transmitted to the far place from the sources and emits noise into the water or outdoor as well as the inner space of the structure. In the case of warships this emission into the water induces noise to reduce the performance of its underwater acoustic equipment. Therefore the structure home noise levels of the installed machineries are strictly limited. This paper shows examples of structure home noise reduction from machineries including pumps.

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Transfer Function of Structure-borne Noise to Underwater Radiated Noise (고체음의 수중방사소음 전달함수)

  • 김재승;김현실;김상렬
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.138-142
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    • 2001
  • A comparison between theoretical and measured transfer function, which relates structure-borne noise source level to underwater radiated noise, of a naval ship is presented in this study. Transfer functions are obtained by dividing far field underwater noise by the value of structure borne noise source levels below machinery mounts. In prediction, statistical energy analysis of the whole ship structure is used to get vibration levels of wetted hull plates below water line. Then, far field radiated noise is calculated by summing up contributions from each plates using vibration levels and radiation efficiencies. And 1/3-octave band underwater sound pressure at the distance of 1 m away from the hull were measured to get experimental transfer functions. The two transfer functions are compared to show resonable agreements in spite of the subtle physical differences between each other.

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Study on the Structure-borne Sound Transmission of a Machine through Rubber Mounts (고무마운트를 통한 장비의 고체음 전달에 관한 연구)

  • Kim, Bong-Ki;Kim, Jae-Seung;Kim, Hyun-Sil;Kang, Hyun-Joo;Kim, Sang-Ryul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.655-660
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    • 2000
  • Machines on board a ship are mounted on decks and transmit its structure-borne sound to the deck through resilient mounts. To predict the ship noise generated by the structure-borne sound of the machine, It is necessary to estimate the vibration level of the base structure. In this paper, a simple dynamic model is considered for vibration isolation systems consisting of a source, an isolator, and a base structure. The high frequency mobilities of the simple base structure are reviewed and wave effects in the mount are discussed in relation to isolation performance.

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Effect of Adsorption of Surfactant to the Particles on Dispersion Stability of Particulate Soil in Anionic-nonionic Surfactant Mixed Solution (음-비이온계 혼합계면활성제 용액에 있어 입자에의 계면활성제 흡착량이 고형오구의 분산안정성에 미치는 영향)

  • 정선영;강인숙
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.436-437
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    • 2003
  • 고형오구의 분산안정화 작용은 고체 입자의 계면에 흡착한 계면활성제에 의한 전기적 반발력과 입체적 보호작용에 영향을 받게 된다. 특히 현재 시판세제의 조성에서 비이온계 계면활성제의 혼합이 점차 중요시되는 이때 입체적 보호작용에 의한 고형오구의 분산안정성은 의류제품의 세척성 제고에 좋은 정보가 되리라 생각된다. 따라서 본 연구는 시판되고 있는 세제 대부분이 음-비이온계 계면활성제의 혼합으로 되어 있는 점을 고려하여 음이온 계면활성제로서 D5S(sodium dodecyl benzene sulfonate), 비이온계 계면활성계 NPE(nonyl phenol polyoxyethylene ether, EO$_{10}$) 혼합용액에서 음이온과 비이온계 계면활성제의 입자에의 흡착과 고형오구의 안정성을 관련시켜 고찰하였다. (중략)

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The Study On Road Noise Affected By Tread Hardness (트레드 물성이 타이어 로드노이즈에 미치는 영향도)

  • Hwang, S.W.;Kim, B.S.;Park, N.;Bang, M.J.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.266-269
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    • 2006
  • Tire is in charge of a lot of function, which is supporting vehicle load, transferring traction and. brake, absorbing impact by road etc. As the silence of vehicle increase more important, the importance of tire noise is more raised. In recent, the study on reduction of tire noise is generally processed. Tire noise is divided in structure home noise and all borne noise. Tire tread properties have a lot of multiplicity. Rubber properties are caused by changing or tread hardness. That change Elastic Modulus and Loss Modulus, which is related by tire noise. In the study, we found that road noise is affected by tread hardness

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