서지주요정보
다공질형 재료의 음향 전파 상수와 특성 임피던스의 결정 = Estimation of sound propagation constant and characteristic impedance of porous materials
서명 / 저자 다공질형 재료의 음향 전파 상수와 특성 임피던스의 결정 = Estimation of sound propagation constant and characteristic impedance of porous materials / 이화수.
저자명 이화수 ; Lee, Hwa-Soo
발행사항 [대전 : 한국과학기술원, 1998].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8008617

소장위치/청구기호

학술문화관(문화관) 보존서고

MME 98065

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

The sound absorbing material is one of the important countermeasures for the control of noise, especially by using passive means. In order to use the absorbing materials most efficiently for given design conditions, the physical parameters and its acoustic characteristics of the materials should be known a priori. In this study, a method based on both of the experiment and the theory has been studied for the estimation of the acoustic propagation constant and the characteristic impedance of porous sound materials, which are most fundamental acoustic properties of materials. The rigid frame model of the porous material was adopted in the underlying governing equations. First, a new measurement method was proposed by using the two loads and three microphones in the duct: the normal incidence of sound was assumed. Two types of porous materials were tested in the experiments: the glass fiber and the polyurethane foam. The measured propagation constant and characteristic impedance were compared with those by the direct method using the conventional two microphone method and by the two cavity method. The results of the proposed method showed very good agreements with those by the existing techniques and could be regarded as very reliable. Second, the measured two acoustic parameters were compared with the theoretical rigid frame models of Biot-Allard, Johnson and Attenborough, and by using the iterative curve fitting to the measured two acoustic parameters, the basic physical parameters of the porous material could be estimated. In this way, the unmeasurable physical parameters such as tortuosity and shape factors could be determined by using the measurable quantities such as porosity, flow resistivity, density, etc. Finally, from the estimated complex density and the bulk modulus of the material, the sound absorption coefficient as a function of the frequency could be predicted and the good agreements with the directly measured results could be observed. The method studied in this thesis is thought to be useful in the efficient application of the sound absorbing porous materials to many practical noise control problems.

서지기타정보

서지기타정보
청구기호 {MME 98065
형태사항 vi, 73 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 : 시편 크기와 장착 상태의 영향
저자명의 영문표기 : Hwa-Soo Lee
지도교수의 한글표기 : 이정권
지도교수의 영문표기 : Jeong-Guon Lee
학위논문 학위논문(석사) - 한국과학기술원 : 기계공학과,
서지주기 참고문헌 : p. 66-68
주제 흡음재
전파 상수
특성 임피던스
물리적 인자
Sound absorbing material
Propagation constant
Characteristic impedance
Physical parameters
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