• Title/Summary/Keyword: Rectangular vibrating surface

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Calculation of Radiation Impedance for Rectangular Piston Vibrators with Finite Baffle (유한배플의 영향을 고려한 정방형 진동면의 방사임피던스계산)

  • 김무준;김천덕;하강열
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.7
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    • pp.3-6
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    • 2000
  • Because the generally reported radiation impedance has been calculated for vibrating surface with infinite baffle, the results have difficulties to apply for design of the real transducers with finite baffle. In this paper, with assuming a vibrating surface as a set of small point sources, a new calculation method for the vibrating surface with finite baffle is suggested by considering the effect of finite baffle on the source strength of each point source. As an example, the variation of self-radiation impedance for rectangular vibrating surface is calculated according to the size of baffle. The results show that the suggested method is useful.

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Study on Sloshing Behaviors in Liquid Storage Tank with Rectangular Cross Section (사각단면 액체저장탱크에서의 슬로싱 거동 연구)

  • 윤성호;이은동;박기진
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1087-1090
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    • 2003
  • In this study, experimental procedures were suggested to investigate the sloshing behavior of a liquid storage tank subjected to inevitably external vibrating conditions. For this purpose. liquid storage tank with rectangular cross section was made of an acrylic resin for the visualization of liquid fluctuation. A specially designed vibrator was used to provide a specified vibrating condition to the liquid storage tank. Extrapolation technique was applied to determine sloshing natural frequency by using various sloshing frequencies at each vibrating displacement and liquid contents at a fixed vibrating frequency. Sloshing mode was also determined from continuous images or liquid fluctuation captured from a video camera. In addition, change in the height of the liquid free surface was measured by using a floating target and a laser displacement sensor. It is found that the suggested method can be applicable to identify the sloshing behavior of liquid storage tank with rectangular cross section.

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Acoustic Radiation Characteristics from Flexible Steel Plate Excited by Acoustic Loading in an Rectangular enclosure (음향 가진된 밀폐계의 유연한 평판의 음향 방사 특성에 관한 연구)

  • 김상헌;안지훈;오재응
    • Journal of KSNVE
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    • v.7 no.3
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    • pp.457-466
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    • 1997
  • The experimental and analytical study was conducted to determine the noise transmission characteristics of acoustically loaded steel plate of rectangular enclosure and to investigate the sound radiation characteristics through out the enclosure. The vibrations of acoustically loaded plate give rise to sound radiations and generate the reverberant space that the sound field exists very close to a vibrating plate. Acoustic transmission loss is measured from the incident intensity into the plate and the transmitted intensity through out the plate. Sound radiation patterns are measured from both acoustic intensity technique and surface intensity technique. Those resultant patterns and vibrational modes are vital in understanding the relations between vibration and noise in the near field out of vibrating plate.

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Calculation of Self-radiation Impedance for a Rectangular Transducer (장방형 트랜스듀서의 자기방사 임피던스 계산)

  • 이기욱;김무준;하강열;김천덕
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.7
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    • pp.85-89
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    • 2000
  • In this paper, by extending the previously developed self- and mutual-radiation impedance calculation method for a regular-square vibrating surface by using numerical series, we proposed a method to obtain the self-radiation impedance of a rectangular transducer with an arbitrary integer ratio of the length to width. The proposed method exhibits high accuracy and a short computation time. After investigating the accuracy and computation time as the number of elements changes, we have calculated the self-radiation impedance of several rectangular transducers, and compared the results with those in the literature.

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Active Structural Acoustic Control for Radiated Sound Reduction in Plate (평판에서의 방사소음 저감을 위한 능동구조음향제어)

  • Hong, Jin-Seok;Oh, Jae-Eung;Lee, You-Yub;Shin, Joon
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.608-612
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    • 2000
  • Active control of sound radiation(using active structural acoustic control) from a vibrating rectangular plate by a steady-state harmonic point force disturbance is experimentally studied. Control structural input are achieved by two piezoceramic actuators bonded to the surface of the panel. Two accelerometers are implemented as error sensors. Estimated radiated sound signals using vibro-acoustic path transfer function are used as error signals. The vibro-acoustic path transfer function represents system between accelerometers and microphones. The control approach are based on a multi-channel filtered-x LMS algorithm. The results demonstrate that attenuation of sound levels of 3dB, 13dB are achieved.

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Review of Membrane Tension Maintenance System for Membrane Structures through Membrane Tension Measurement (막장력 측정을 통한 막구조물의 장력 유지관리 시스템 검토)

  • Jin, Sang-Wook;Shon, Su-Deok;Lee, Seung-Jae
    • Journal of Korean Association for Spatial Structures
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    • v.16 no.2
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    • pp.39-45
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    • 2016
  • Membrane structure is a system that is stabilized by maintaining a tensile state of the membrane material that originally cannot resist the bending or pressure. Also, it is a system that allows the whole membrane structure to bear external loads caused by wind or precipitation such as snow, rain and etc. Tension relaxation phenomenon can transpire to the tension that is introduced to the fabric over time, due to the innate characteristics of the membrane material. Thus, it is important to accurately understand the size of the membrane tension after the completion of the structures, for maintenance and management purposes. The authors have proposed the principle of theoretically and indirectly measuring the tension by vibrating the membrane surface with sound waves exposures against the surface, which is compartmentalized by a rectangular boundary, and by measuring the natural frequency of the membrane surface that selectively resonates. The authors of this paper measured the tension of preexisting membrane structure for its maintenance by using the developed portable measurement equipment. Through analyzing the measurement data, the authors review the points that should be improved and the technical method for the new maintenance system of membrane tension.