• Title, Summary, Keyword: Sound Transmission Loss

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An Experimental study to Improving the Sound Transmission Loss of Honeycomb sandwich Plates (허니컴 샌드위치판의 투과손실 개선에 관한 실험적 연구)

  • 유영훈;양보석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.2
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    • pp.92-99
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    • 1998
  • The sound insulation capacity of honeycomb sandwich plates which have relatively higher strength ratios to weight is poorer than those of uniform and another sandwich plates. Therefore, improvement of the sound insulation capacity of the honeycomb sandwich plate which has a meritof lightness is required to use it in automobile and rapid rail road industries. In this study, to improving the sound insulation capacity of the honeycomb sandwich plate, the sound transmission loss of the structure is experimentally investigated by adding a viscoelastic damping layer, The effective add position and thickness of the layer were investigated from the viewpoints of both sound transmission loss and improved sound transmission loss over the frequency range from 800Hz to 10kHz.

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Tunneling Effect on Sound Transmission Loss Measurement (차음성능 계측시 터널링 효과에 관한 해석적 연구)

  • 김봉기;김재승;김현실;강현주;김상렬
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1228-1233
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    • 2002
  • This study is aimed to evaluate a tunneling effect in association with the measurement of sound transmission loss. Based on the formulation for sound transmission loss of a finite panel in the presence of tunnel, variations of the sound transmission loss with parameters such as the location of panel and tunnel depth are investigated. It can be seen that differences in the sound transmission loss are quite evident below coincidence frequency and the sound transmission loss greatly depends on panel location in the tunnel. In comparison with the case without a tunnel, maximum difference occurs in the case where the panel is placed on the center of the tunnel and the flushing with the end of the tunnel gives the better estimation of transmission loss.

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Sound Transmission Performance of Composite panels : Reverberation chamber vs. Cabins in Ship (복합판넬의 차음특성 비교 : 잔향실과 실선)

  • Kang, Hyun-Ju;Kim, Jae-Seung;Kim, Hyun-Sil;Kim, Sang-Ryul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.843-848
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    • 2000
  • This paper deals experimently with the difference between the cabins in ship-board and the reverberation chamber in sound transmission loss. Experimental results from the cabins show that there are various flanking transmission losses which deteriorate significantly the performance of the sound transmission loss. They also show that as a representative of the flanking transmission losses, sound leakages between a ceiling and a wall, the joints of the partitions, and the luminant devices play an important role. From the various measurements, it can be is concluded that unless one do not take any treatments on the flanking transmission loss, the field sound transmission loss will be considerably decreased by more than 10 dB, comparable to the sound transmission loss.

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A Study on Tunneling Effect in Sound Transmission Loss Measurement (차음성능 측정시 터널링 효과에 관한 연구)

  • Kim, Bong-Ki;Kim, Jae-Seung;Kim, Hyun-Sil;Kang, Hyun-Ju;Kim, Sang-Ryul
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.1E
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    • pp.24-30
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    • 2004
  • This study is aimed to evaluate a tunneling effect in the laboratory measurement of sound transmission loss. Based on the formulation for sound transmission loss of a finite panel in the presence of tunnel, variations of the sound transmission loss with the parameters of panel location and tunnel depth are investigated. In comparison with the transmission loss of a finite plate in an infinite rigid baffle, the maximum difference occurs in the laboratory measurement when the panel is placed at the center of the tunnel, while a better estimation of true transmission loss is obtained when the panel is located at either end.

The Limit and Application of Two-microphone Impedance Tube Method to the Sound Transmission Loss Measurement of Sound Isolation Materials (차음재의 음향투과손실 측정에 Two-Microphone Impedance Tube Method의 적용과 한계)

  • Lee, Seung;Ahn, Min-Hong;Lee, Dong-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.883-888
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    • 2002
  • This study describes the limit and application of the two-microphone impedance tube method to the sound transmission loss measurement of several sound isolation materials with different physical properties. For the sound isolation materials having small flexural rigidity, it is shown that the two-microphone impedance tube method is validated to practically measure the sound transmission loss. For the sound isolation materials having large flexural rigidity, on the other hand, it is found that the two-microphone impedance tube method is no longer valid to measure the sound transmission loss because the regions of resonance and mass law are moved into the higher frequencies. In addition, in order to accurately measure the sound transmission loss of sound isolation materials, their size should be decided based on the consideration of the effect of acoustic excitation on their vibration response.

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New Method for Measurement and Validation of In-situ Sound Transmission Loss (In-situ 소음투과손실 측정 및 검증을 위한 기법 개발)

  • Lee, Hwa-Soo;Park, Hong-Cheol;Yoon, Seong-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.795-800
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    • 2008
  • The sound transmission loss is a key index to evaluate the acoustic performance of a car-body structure at the high frequency range. From this paper, a new validation method for in-situ sound transmission loss is proposed. First, in-situ sound transmission loss is measured by using PU intensity probe on the condition of complete vehicle. Second, validation test, which is consisted of internal, external and total frequency response function test, is performed by using volume acceleration source and microphones. Then, these test results are compared to validate the accuracy of in-situ sound transmission loss. Finally, the test result of in-site method is compared with results of two reverberant room test method and SEA analytical method. The reliability of in-situ method is confirmed by these procedures.

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Development of a Practical Two-Microphone Impedance Tube Method for Sound Transmission Loss Measurement of Sound Isolation Materials

  • Ro, Sing-Nam;Hwang, Yoon;Lee, Dong-Hoon
    • International Journal of Air-Conditioning and Refrigeration
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    • v.11 no.3
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    • pp.105-113
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    • 2003
  • This study developed a practical two-microphone impedance tube method to measure the sound transmission loss of sound isolation materials without the use of an expensive reverberation room or an acoustic intensity probe. In order to evaluate the validation and applicability of the two-microphone impedance tube method, sound transmission losses for several sound isolation materials with different surface density and bending stiffness were measured, and the measured values were compared with the results from the reverberation room method and the theory. From the experimental results, it was found that the accuracy of sound transmission loss obtained by the impedance tube method depends upon the diameter size of the impedance tube (i.e., tested sample size). For sound isolation materials having relatively large bending stiffness such as acryl, wood, and aluminum plates, it was found that the impedance tube method proposed by this study was not valid to measure the sound transmission loss. On the other hand, for sound isolation materials having relatively small bending stiffness such as rubber, polyvinyl, and asphalt sheets, the comparisons of transmission loss between the results from the impedance tube method and the theory showed a good agreement within the range of the frequencies satisfying the normal incidence mass law. Therefore, the two-microphone impedance tube method proposed by this study can be an effective measurement method to evaluate the sound transmission loss for soft sound isolation sheets having relatively small bending stiffness.

Measurement of Sound Transmission Loss in a Sound Barrier Filled with the Rice-Straw Particles by the Transfer Function and Laboratory Measurement Methods

  • Kang, Chun-Won;Jang, Eun-Suk;Jang, Sang-Sik;Kang, Ho-Yang
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.4
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    • pp.338-345
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    • 2018
  • The sound insulation capacity of a barrier is indicated by its transmission loss. In this study, the sound transmission loss of a sound barrier filled with rice-straw particles was measured by the transfer function method and a laboratory measurement method. The results of the two measurements were compared. The transmission losses measured by the two methods were similar above a frequency of 500 Hz. The loss increased greatly upon the introduction of a plywood to the sound barrier. The results of this study are expected to be used to design sound barriers for roads.

Sound Transmission Loss of Aluminium Extruded panels for Railway vehicles (철도차량용 알루미늄 압출재의 투과손실)

  • 김석현;박정철;김종년
    • Journal of KSNVE
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    • v.10 no.4
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    • pp.662-668
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    • 2000
  • Sound transmission characteristics are investigated on the aluminium extruded panels used for railway vehicles. An equivalent orthotropic plate model and mass law are applied to predict the sound transmission loss. An extruded panel specimen used in the floor of railway vehicles is manufactured and is tested to measure sound transmission loss by two reverberant chamber method. Predicted transmission loss I compared with measured values and the effect of local resonance on the transmission characteristics is identified. The results are applied to design the extruded panel having better sound insulation performance.

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Sound Insulation Performance of Corrugated Panels for Rail Way Vehicles (철도차량용 주름판재의 차음성능)

  • Kim, Seock-Hyun;Park, Jung-Mo
    • Journal of Industrial Technology
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    • v.20 no.B
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    • pp.9-14
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    • 2000
  • Sound insulation performance is investigated on the corrugated panel used for a rail way vehicle. Random incidence sound transmission loss is calculated by using the equivalent orthotropic plate model. Analysis results on several kinds of corrugated panels are in good agreement with the measured data. The analysis method is applied to predict the sound transmission loss of the corrugated panel used for Korean high speed train.

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