한국소음진동공학회논문집 (Transactions of the Korean Society for Noise and Vibration Engineering)

  • 제18권6호
  • /
  • Pages.598-605
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  • 2008
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  • 1598-2785(pISSN)
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  • 2287-5476(eISSN)
한국소음진동공학회 (The Korean Society for Noise and Vibration Engineering)
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자유 음장 조건에서 개선된 빔형성 방법을 이용한 흡음재의 수직 입사 표면 임피던스 측정

Measurement of Normal Incidence Surface Impedance of Absorbing Materials Using the Improved Beamforming Method in a Free Field

  • 신창우 (서울대학교 기계항공공학부) ;
  • 선종천 (서울대학교 기계항공공학부) ;
  • 강연준 (서울대학교 기계항공공학부) ;
  • 백순권 (현대.기아자동차)
  • 발행 : 2008.06.20
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초록

An improved beamforming method is proposed to measure the surface impedance of absorbing materials in a free field. It is possible to estimate the surface impedance by decomposing measured signals into incident and reflected signals by using the spatial filter matrix of the beamforming method. Wavelet do-noising techniques which reduce the white Gaussian noise are applied to improve the results. Phase calibration method is also used to improve the results of the measured surface impedance in a low frequency range. The results of the normal incidence experiments that are performed in a semi-anechoic chamber are verified by comparing with those of the standard test method that is presented in ASTM E1050. The proposed method is found to be reliable to measure the surface impedance for frequencies higher than 400 Hz.

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참고문헌

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