• 제목/요약/키워드: acoustic absorbent

검색결과 14건 처리시간 0.038초

공기층을 갖는 공조덕트 구조물에서 흡음재의 흡음특성에 관한 연구 (A Study on the Absorption Characteristics of Absorbents in Duct System with the Air Cavity)

  • 김찬묵;김도연;방극호
    • 소음진동
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    • 제10권5호
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    • pp.892-897
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    • 2000
  • In this paper, experimental methods to find acoustic characteristics of acoustically treated air-conditioning duct system are proposed. Existing methods to analyze acoustic properties of duct with absorbent material have dilemma which has to assume the wave in duct to be a plane wave. Under this assumption. applicable frequency limitation makes accurate analysis of practical air-conditioning system impossible. In order to analyze the properties of in-lined treated absorbent with high degree of accuracy, in this experiments the range of exciting frequency of sound source is broadband, which means that source speaker excited higher mode of in-duct sound field. Also, to define the relations of air cavity to the acoustic characteristics, acoustic experiments on ducts with air cavity of different depth are operated. In conclusion, air-cavity makes the absorbing ability of duct improved in low frequency range. Due to the interactions between the air cavity depth and the depth of absorbents, according to depth of cavity, the magnitude of absorption coefficients vs frequencies in specific range is changed. In lower frequency range, the absorption of sound energy by air cavity is more dominant than by absorbent itself, in higher range, the inversion is true.

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유한요소법에 의한 흡음재 음향특성 연구 및 검증 (Finite Element analysis of Acoustic Behavior of Absorbent Materials with experimental Verification)

  • 정환익;김관주;박진규;김상헌
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 추계학술대회논문집
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    • pp.874-878
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    • 2003
  • Acoustic materials are used for the purpose of absorbing noise and reducing transmission of sound into the receiving room. The purpose of this research is to predict the performance of absorbent materials with respect to absorbing behavior and transmission loss as possible as accurately. The performance of the absorbent materials are carried out systematically as follows: The Biot parameter are measured, first. Then using above parameters as input, LMS's SYSNOISE and VIOLINS programs are used to predict absorption coefficient and transmission loss values, which magnitudes are compared with experimental results. As an sample acoustic material, SK SKY VIVA and PET are selected.

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흡음형 방음판넬의 음향특성 (The Acoustical Characteristics of an Absorptive Panel)

  • 황철호;정성수;이우섭;김용태
    • 대한환경공학회지
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    • 제22권10호
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    • pp.1843-1850
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    • 2000
  • 다공판과 흡음재, 그리고 공기총으로 구생되는 방음판에 대한 흡음계수를 측정하고 이론값과 비교하였다. 방음판은 세 가지 기본적인 조합물(다공판 + 공기층 + 흡용재, 다공판 + 흡음재, 다공판 + 흡음재 + 공기층)으로 구성하였다. 실험결과 저주파수 영역의 흡음력은 다공판과 공기층으로 구성되는 공명형 구조물의 공명 흡음에, 그리고 고주파수 영역은 다공판의 기공률에 크게 영향을 받음을 알 수 있었다.

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공기층을 갖는 실제덕트 구조물에서의 소음저감에 관한 연구 (A study on the noise reduction of practical duct system with the air cavity)

  • 김찬묵;이두호;방극호
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.1687-1692
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    • 2000
  • In this paper, experimental methods to find acoustic characteristics of acoustically treated air-conditioning duct system are proposed. Existing methods to analyze acoustic properties of duct with absorbent material have a dilemma which has to assume the wave in duct to be a plane wave. Under this assumption, applicable frequency limitation makes accurate analysis of practical air-conditioning system impossible. In order to analyze the properties of in-lined treated absorbent with high degree of accuracy, in this experiments the range of exciting frequency of sound source is broadband, which means that source speaker excites higher mode of in-duct sound field. Also, to define the relations of air cavity to the acoustic characteristics, acoustic experiments on ducts with air cavity of different depth are operated. In conclusion, air-cavity makes the absorbing ability of duct improved in low frequency range. Due to the interactions between the air cavity depth and the depth of absorbents, according to depth of cavity, the magnitude of absorption coefficients vs frequencies in specific range is changed. In lower frequency range, the absorption of sound energy by air cavity is more dominant than by absorbent itself, in higher range, the inversion is true.

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흡음재 내부의 음향전파가 고려된 2차원 흡음형 소음기의 음향성능 예측 (Prediction of the acoustic performance of the two-dimensional dissipative silencer with the propagation of sound in the absorbent)

  • 김회전;이정권
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 추계학술대회논문집
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    • pp.870-873
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    • 2003
  • This research is about the sound attenuation in the duct with lining sound absorbing material in it. Many previous researches assumed the property of lining material as locally-reacting. As the thickness of lining material thickens or the upper limit of the interested frequency range goes higher, there is a growing tendency for the experiment results to deviate from the theoretical results based on the locally reacting assumption. In this paper, the acoustic performance of the two-dimensional dissipative silencer with the propagation of sound in the absorbent was derived theoretically and calculated. The effect of increase of sound absorbing material is also considered. These results are compared from the previous results with using the locally-reacting property of sound absorbing material.

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흡음재 배치를 통한 닫힌 공간에서의 소음원 방사 파워 제어 (Radiation Power Control by Means of Absorptive Material Arrangement in an Enclosure)

  • 조성호;김양한
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 춘계학술대회논문집
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    • pp.688-691
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    • 2004
  • We have studied the possibility of global noise reduction by the sound power control through selection of distribution and impedance of absorptive materials. It is necessary to investigate the relation between the global sound energy in the field and the total sound power radiated by sources. In the previous work (1,2), the authors presented a useful design method to change boundary condition that can be useful to reduce noise in acoustically small enclosures. The possibility of total acoustic potential energy reduction by acoustic source power control is examined in an acoustically small cavity. Using acoustic energy balance equation, the relation between global noise control performance and absorptive material's arrangement/impedance is deduced. Numerical simulation is performed to interpret its physical meaning in terms of absorbent's distribution and impedance.

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흡음재의 배치와 임피던스 선정을 통한 음원 방사파워 제어와 전역 소음 감소 (Acoustic Source Power Control and Global Noise Reduction by Selection of Distribution and Impedance of Absorptive Materials in Acoustically Small Enclosures)

  • 김양한;조성호
    • 한국소음진동공학회논문집
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    • 제14권8호
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    • pp.668-674
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    • 2004
  • The possibility of global noise reduction by the sound power control through selection of distribution and impedance of absorptive materials is discussed. It is necessary to investigate the relation between the global sound energy in the field and the total sound power radiated by sources. In the previous work,$^{(1.2)}$ the authors presented a useful design method to change boundary condition that can be useful to reduce noise in acoustically small enclosures. Changing boundary condition Is related to not only enclosure’s geometrical shape but also acoustical treatment on walls for example, attaching of impedance patches (ex: absorptive material). In many practical situations, we often meet situation to change acoustical treatment on walls. The possibility of total acoustic potential energy(globa1 noise) reduction by acoustic source power control is examined in an acoustically small cavity Using acoustic energy balance equation, the relation between global noise control performance and absorptive material’s arrangement/impedance is deduced. Numerical simulation is performed to interpret its physical meaning in terms of absorbent’s distribution and impedance.

흡음재의 종류에 따른 진공청소기의 흡음성능 특성 연구 (A Study on Acustic absorption Efficiency of Vacuum cleaner by Kind of Acustic absorbent)

  • 김정훈;조태정;정지원;최명진;이순걸
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.687-692
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    • 2007
  • Vacuum cleaner, one of those household articles, have easily used in our life. Recently vacuum cleaner tends to be compact and portably with high suction power and low noise. As increasing this suction power, the vibration and noise of vacuum cleaner become important problem. To reduce noise efficiently, it is important to identify the noise and the vibration. This pater is to characterize the noise and vibration of a vacuum cleaner.

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Acoustic performance of industrial mufflers with CAE modeling and simulation

  • Jeon, Soohong;Kim, Daehwan;Hong, Chinsuk;Jeong, Weuibong
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제6권4호
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    • pp.935-946
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    • 2014
  • This paper investigates the noise transmission performance of industrial mufflers widely used in ships based on the CAE modeling and simulation. Since the industrial mufflers have very complicated internal structures, the conventional Transfer Matrix Method (TMM) is of limited use. The CAE modeling and simulation is therefore required to incorporate commercial softwares: CATIA for geometry modeling, MSC/PATRAN for FE meshing and LMS/SYSNOISE for analysis. Main sources of difficulties in this study are led by complicated arrangement of reactive elements, perforated walls and absorption materials. The reactive elements and absorbent materials are modeled by applying boundary conditions given by impedance. The perforated walls are modeled by applying the transfer impedance on the duplicated node mesh. The CAE approach presented in this paper is verified by comparing with the theoretical solution of a concentric-tube resonator and is applied for industrial mufflers.