• 한국소음진동공학회논문집
• /
• 제18권12호
• /
• pp.1262-1269
• /
• 2008

Though multilayered foam-panel structures have been widely used to reduce sound transmission in various fields, most of the previous works to design them were conducted by repeated analyses or experiments based on initially given configurations or sequences. Therefore, it was difficult to obtain an optimal sequence of multilayered foam-panel structure yielding superior sound isolation capability. In this work, we propose a new design method to sequence a multi-panel structure lined with a poroelastic material having maximized sound transmission loss. Being formulated as a one-dimensional topology optimization problem fur a given target frequency, the optimal sequencing of panel-poroelastic layers is systematically carried out in an iterative manner. In this method, a panel layer is expressed as a limiting case of a poroelastic layer to facilitate the optimization process. This means that main material properties of a poroelastic material are treated as interpolated functions of design variable. The designed sequences of panel-poroelastic multilayer were shown to be significantly affected by the target frequencies; more panels were obtained at higher target frequency. The sound transmission loss of the system was calculated by the transfer matrix derived from Biot's theory.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 추계학술대회 논문집
• /
• pp.597-600
• /
• 2009

Sound transmission loss (TL) is experimently investigated on the multi-layered panel used for the floor of a tilting train. Measurement of the intensity transmission loss is performed according to ASTM E 2249-02. The floor structure consists of corrugated steel panel, glass wool, plywood and cover. On the corrugated steel panel, TL drop by local resonance is considered and the TL improvement effect by damping treatment is estimated. Total sound transmission loss of the entire floor structure is obtained and the contribution of each layer is examined.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.326-331
• /
• 2011

Aluminum extruded panel used in a high speed train shows high stiffness, however, its sound insulation performance is remarkably decreased by local resonance phenomena. In this paper, improvement strategy of the sound insulation performance is proposed for the floor extruded panel used in HEMU-400x, 400km/h class next generation high speed train under development, and the improvement effect is verified by experiment. Aluminum extruded panel specimen for the floor is manufactured and urethane foam is installed in the core of the panel. Based on ASTM E2249-02, intensity transmission loss is measured and the improvement effect in local resonance frequency band is verified. Finally, improvement effect of the sound insulation performance is estimated on the layered floor structure including the foamed aluminum panel.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.1478-1485
• /
• 2011

이 기술은 지하철 역사 특성상 천정판 개방이 수반되는 보수공사와 각종점검이 수시로 이루어지고 있는 바, 잦은 탈 부착으로 천정판이 쉽게 탈락 및 훼손되어 역사 유지관리에 어려움이 발생되고 있는 문제를 해결하기 위해 천정판의 설치 방법을 고정방식에서 탈피하여, 일부분을 미닫이 방식으로 개폐할 수 있도록 설치함으로서 천정판의 탈 부착으로 인한 훼손을 방지하고 내구성을 증대시켜 역사 천정판 교체공사 주기를 연장시키고 이에 따른 유지관리 비용 절감 효과가 있는 천정판 시공방법을 제시코자 함.

• 한국소음진동공학회논문집
• /
• 제15권8호
• /
• pp.924-930
• /
• 2005

Sound absorptive materials have good performance in high frequency range, not at low frequencies. Therefore it has been great challenge to develop a sound absorbing structure that is good at low frequency. We propose to use a Helmholtz resonator array panel for this purpose. A Helmholtz resonator is one of noise control elements widely used in many practical applications. The resonator is a simple structure composed of a rigid-walled cavity with a neck, but it has very high performance at resonance frequency. This paper discusses the sound absorption of Helmholtz resonator array panels at normal and random incidence. First, various experimental results are introduced and studied. Secondly, we theoretically predict the absorptive characteristics of the resonator away panel. The theoretical approach is based on the Fourier analysis for a periodic absorber. We believe that this method can be used to design a panel for low frequency noise control.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 추계 학술논문 발표대회
• /
• pp.161-163
• /
• 2011

Due to various kind of waterproof materials and methods, which is difficult to select the most appropriate to waterworks. The materials used to prevent the deterioration of the service life is short, because of the chemical erosion. So, in the 2010 Office of Waterworks Seoul Metropolitan Government has set new standards. Recently, SMC panel is a trend that is being applied to water treatment facilities. However, SMC panel has not yet implemented a performance evaluation. Therefore, this study to confirm that satisfaction for the Office of Waterworks Seoul Metropolitan Government of the performance requirements, when the applied the SMC panel to water treatment structure.

• 한국진공학회지
• /
• 제19권1호
• /
• pp.28-35
• /
• 2010

플라즈마 디스플레이 패널에서 명실콘트라스트(bright room contrast ratio: BRCR)를 개선하는 방향으로 새로운 전극구조를 설계하였다. 새로운 개념의 전극을 이용하여 블랙매트릭스 패턴의 영역을 넓힐 수 있었으며 이를 통하여 패널면의 반사휘도를 낮출 수 있었다. 제작한 플라즈마 디스플레이 패널에 대하여 방전전압, 방전효율, 휘도 등을 평가하였으며 명실콘트라스트가 크게 개선됨을 확인하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1097-1102
• /
• 2009

In a railway vehicle, corrugated steel panel is widely used for the floor panel because of its high bending stiffness and light weight. However, this panel shows lower sound insulation performance than that of the plate with the same weight. Especially, in a particular frequency band, transmission loss (TL) rapidly decreases and it results in the deterioration of TL of the overall floor panel. This study identifies that the remarkable drop in TL is caused from the local resonance of the periodic corrugated structure. This study shows that the frequency band of the TL drop can be controlled by the proper design of the corrugated structure. In addition, improvement effect of TL by attaching foam and glass wool is estimated by experiment. The purpose of the study is to provide the practical information for the improvement of the sound insulation performance of the corrugated steel.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
• /
• pp.203-204
• /
• 2000

We have developed 14.1" XGA transflective panel for both transmissive mode and reflective mode. We designed new panel structure, optimized optical films and adopted pixel with high aperture and high transmittance color filter. This can be applied for mobile tool and sub-note without regard to environment.

• Smart Structures and Systems
• /
• 제20권5호
• /
• pp.595-605
• /
• 2017

The present article reported the thermal buckling strength of the sandwich shell panel structure and subsequent improvement of the same by embedding shape memory alloy (SMA) fibre via a general higher-order mathematical model in conjunction with finite element method. The geometrical distortion of the panel structure due to the temperature is included using Green-Lagrange strain-displacement relations. In addition, the material nonlinearity of SMA fibre due to the elevated thermal environment also incorporated in the current analysis through the marching technique. The final form of the equilibrium equation is obtained by minimising the total potential energy functional and solved computationally with the help of an original MATLAB code. The convergence and the accuracy of the developed model are demonstrated by solving similar kind of published numerical examples including the necessary input parameter. After the necessary establishment of the newly developed numerical solution, the model is extended further to examine the effect of the different structural parameters (side-to-thickness ratios, curvature ratios, core-to-face thickness ratios, volume fractions of SMA fibre and end conditions) on the buckling strength of the SMA embedded sandwich composite shell panel including the different geometrical configurations.