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구조-음향 연성현상을 갖는 방사 방향을 가질 수 있는 방사체 설계방법
서희선(Seo, Hee-Seon),김양한(Kim, Yang-Hann) 한국소음진동공학회 2005 한국소음진동공학회 논문집 Vol.15 No.2
This paper presents a design method for the structural-acoustic coupled radiator that can emit sound in the desired direction. A coupled system that has a finite space and a semi-infinite space separated by two flexible walls and an opening is considered. An objective function is selected to maximize radiation power on a main axis and minimize a side lobe level. To get initial values, prediction of a pressure distribution on field points and radiation pattern of the structural-acoustic coupling system is shown at a coupled-resonant frequency. Three different optimization methods are adapted to design the coupled radiator. Pressure and intensity distribution of the designed radiator is presented.
서희선(Seo, Hee-Seon),조요한(Cho, Yo-Han),조치영(Joh, Chee-Young) 한국소음진동공학회 2007 한국소음진동공학회 논문집 Vol.17 No.9
A study was carried out to investigate the fluid-structure interaction phenomena of buried hydrophone system that exposed complex loads due to handling, transportation and installation. The buried hydrophone system has necessarily neighborhood structures for installation. Because of the neighborhood structure, acoustic field is deformed. We analyze the piezoelectric-structural-acoustic coupled problem and the results to use a finite element analysis software, ANSYS, which has an coupled field analysis capability. The effect of the component of hydrophone system is revealed altogether in pressure distribution. So, we classify and analyze the problem by four different compositions for decomposition.
입구와 유연한 구조물로 구성된 경계를 가지는 구조-음향 연성계의 수학적 표현
서희선(Seo, Hee-Seon),김양한(Kim, Yang-Hann) 한국소음진동공학회 2005 한국소음진동공학회 논문집 Vol.15 No.5
This paper explains a general coupling system in terms of the system parameters. impedance of a cavity or mobility of a structure. To easily access the mechanism of the structural-acoustic coupled system, a simple expression is derived. A general coupled equation is also derived of a general coupled problem constituted a flexible structure and an opening boundary in terms of vector and matrix notation, and is analyzed the coupling phenomena using the understanding acquired simple coupled system. The paper shows that the general coupled equation is expanded version of the simple coupled equation by some limiting checks. The paper also shows that the degree of coupling is proportioned to a stiffness of the acoustic system and a modal coupling coefficient, but is in inverse proportion to a mass of the structural system and the difference of the excitation frequency and resonant frequency of the acoustic or structural system.
조치영,서희선,이정민,Joh, Chee-Young,Seo, Hee-Seon,Lee, Jung-Min 한국음향학회 1996 韓國音響學會誌 Vol.15 No.4
본 연구에서는 샌드위치형 압전 트랜스듀서의 등가 회로 모델을 규명하는 방법을 제시하였다. 공기중에서 실험적으로 측정한 트랜스듀서의 전기적 어드미턴스와 이론적으로 계산된 어드미턴스의 오차가 최소가 되도록 하는 비선형 최적화 문제를 풀어 등가 회로에 관련된 미지 상수를 규명하였다. 예제 트랜스듀서에 대해 제안된 방법을 적용하여 등가회로를 모델링하고, 수중에서의 송신 음압 감도(TVR) 및 수신 읍압 감도(RVS)을 예측하고 실험치와 비교하여 규명된 등가 회로 모델의 타당성을 검증하였다. In this paper an identification method is presented to obtain the equivalent electric model of a sandwitch type piezoelectric transducer. Unknown parameters related to the equivalent circuit are identified by solving a nonlinear optimization problem which can minimize an error between the experimental and analytical admittances in air. The proposed method is applied to an example transducer. The validity of equivalent circuit model is demonstrated by the comparison between the experimental measurements and analytical calculations of transmitting voltage response(TVR) and receiving voltage response(RVS).