• 한국자동차공학회논문집
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• 제15권6호
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• pp.50-61
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• 2007

The structural stiffness, strength and stability on the bodyshell and floor structures of the Korean Low Floor Bus composed of laminate, sandwich panels and metal reinforced frame were evaluated. The laminate composite panel and facesheet of sandwich panel were made of WR580/NF4000 glass fabric/epoxy laminate, while aluminum honeycomb or balsa was applied to the core materials of the sandwich panel. A finite element analysis was used to verify the basic design requirements of the bodyshell and the floor structure. The use of aluminum reinforced frame and honeycomb core was beneficial for weight saving and structural performance. The symmetry of the outer and inner facesheet thickness of sandwich panels did not affect the structural integrity. The structural strength of the panels was evaluated using Von-Mises criterion for metal structures and total laminate approach criterion for composite structures. All stress component of the bodyshell and floor structures were safely located below the failure stresses. The total laminate approach is recommended to predict the failure of hybrid sandwich composite structures at the stage of the basic design.

• Steel and Composite Structures
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• 제46권5호
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• pp.659-667
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• 2023

Nonlinear forced vibration behaviors of sandwich plates having graphene platelets (GPL) based face sheets have been researched in this article. Possessing low weight together with low stiffness, square honeycomb cores are mostly constructed by aluminum. Herein, the square shaped core has been fortified by two skins of GPL-based type in such a way that the skins have uniform and linearly graded GPL dispersions. The square shaped core has the effective material specification according to the relative density concept. The whole formulation has been represented based upon classical plate theory (CPT) while harmonic balance approach is applied for solving the problem and plotting the amplitude-frequency curves. The forced vibration behaviors of such plates are influenced by square-shaped core and the relative density, skin's height and GPL fortification.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.82-89
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• 2007

Sound transmission characteristics are investigated on the corrugated steel and aluminium extruded panels used for railway vehicles. Sewell-Sharp-Cremer(SSC) model, equivalent orthotropic plate model and equivalent mass law are applied to predict the sound transmission loss. The predicted values of the sound transmission loss are compared with the measured values. The reliability and the limitation of the prediction models are investigated. For the corrugated panels and honeycomb panels, the coincidence and local resonance severely deteriorate the sound insulation performance around the corresponding frequency bands. The result of the study shows that the equivalent orthotropic plate model and the SSC model can be used as good prediction models, if the coincidence frequency or local resonance frequency is correctly applied.

• Composites Research
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• 제20권4호
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• pp.42-50
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• 2007

본 논문에서는 바이모달 트램의 차체와 바닥재 구조 재료로 적용되는 2종류의 샌드위치 패널에 대한 충격 손상을 시험과 수치해석을 통해 상호 비교하였다. 적용된 시편은 $100mm{\times}100mm$의 크기를 가지며 저속충격시험기를 사용하여 4가지 경우의 충격에너지에 대해 시험하였다. 또한, 저속충격 조건에 따라 차체 적용 샌드위치 구조물의 저속 충격 특성을 유한요소해석으로 분석하기 위해 범용 외연유한요소해석 프로그램인 LS-DYNA3D를 이용하여 특성을 분석하였다. 이때 금속재와 복합재 재료의 손상모델, 그리고 직교이방성 특성을 갖는 하니컴 재료의 유효손상모델을 제시하기 위하여 기계적 특성 시험을 수행하여 물성 파라메터를 획득하였고, 시험과 해석결과 충격 하중에 대한 샌드위치 패널의 손상 영역과 깊이를 비교적 잘 예측할 수 있음을 증명하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.74-77
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• 2001

The impact response and damage of CLAS panel was investigated experimentally. The facesheet material used was RO4003 woven-glass hydrocarbon/ceramic and the core material was Nomex honeycomb with a cell size of 3.2mm and a density of 96 kg/$\textrm{m}^{3}$. The shield plane used was RO4003 and 2024-T3 aluminum. Static indentation and impact test was conducted to characterize the type and extent of the damage observed in two CLAS panels, and the performance of antenna used in a wireless LAN system. Correlation of peak contact force, residual indentation and the delamination area shows impact damage of the panel with an aluminum shield plane is larger than that of the panel with RO4003 shield plane, although tile former is more penetration resistant. The damage was observed by naked eye, ultrasonic inspection and cross sectioning. The shape and size of delamination was estimated by ultrasonic inspection, and the area of delamination linearly increases as impact energy increases. The performance of impact damaged antenna was estimated by measuring return loss and radiation pattern.

• Composites Research
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• 제14권6호
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• pp.1-8
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• 2001

본 연구에서는 샌드위치 패널 구성 요소인 면재와 심재를 변화시켜 4종류의 샌드위치 패널을 제작하였다. 그리고 제작된 샌드위치 패널의 기계적 특성과 철도차량 개발시 중요한 요인으로 작용하는 음향투과 특성 그리고 화재에서의 안정성을 확인하기 위하여 난연특성 실험을 통하여 샌드위치 패널의 특성을 검토하고자 하였다. 샌드위치 패널의 기계적 특성은 알루미늄 면재 + 알루미늄 하니컴 심재로 구성된 샌드위치 패널이 면방향 인장강도와 변방향 압축강도 특성에서 우수하며 알루미늄 면재 + 노멕스 하니컴 심재로 구성된 샌드위치 패널은 면방향 압축강도와 굽힘 강도가 우수한 것으로 확인되었다. 알루미늄 면재 + PMI 포옴 심재로 구성된 샌드위치 패널은 심재의 전단강도 및 면재의 굽힙강도가 우수하였다. 난연성 시험에서는 phenol 수지 면재와 2종의 외국 면재는 모든 시험 결과에서 유사한 견과를 확인하였다.

• 한국태양에너지학회 논문집
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• 제30권2호
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• pp.10-15
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• 2010

The experimental study was conducted to optimize the system dissipating properly heat from the in-situ solar panel installed on the roof. For this purpose, six 12-Watt panels, which were consisted of the different design conditions such as containing phase change material(PCM), changing the array of the aluminum fin and honeycomb at the back of the panel, were tested. PCM, which had $44^{\circ}C$ melting point, was chosen in this study. In order to enhance absorbing and expelling heatin PCM, profiled aluminum fin was placed either inward oroutward from the panel. Furthermore, Aluminum honeycomb is imbedded in the back container to find if it would improve the thermal conductivity of PCM. During the experiment, there were ranged to $26^{\circ}C\sim32^{\circ}C$ for outdoor temperature and $700W/m^2\sim1000W/m^2$ for irradiance. As a result, the solar panel, combined with honeycomb and outward fins with PCM instead of placing the fins inward, is showing the best performance in terms of controling panel temperature and its efficiency.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.721-724
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• 2005

With the advantages of large vibration energy dissipation of structures, the granular materials are used as vibration and acoustic treatments. In this case of vibro acoustic controls, a finite dynamic strength of the solid component (frame) is an important design factor. The dynamic stiffness of hollow cylindrical beams containing porous and granular materials as damping treatment was measured. Using the Rayleigh-Ritz method, the effects of damping materials on the dynamic characteristics of beams were investigated. The results suggested that the acoustic structure Interaction between the frame and the structure enhances the dissipation of the vibration energy significantly. The same methods were applied also to vibration control of sandwich panels. By filling the cavities of honeycomb cores using unconsolidated granular materials, its sound transmission toss was improved significantly.

• Composites Research
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• 제19권1호
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• pp.9-14
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• 2006

본 연구는 KS F 2278 2003 (창호의 단열성 시험 방법)에 의하여 철도차량 및 버스의 내/외장재로 적용 가능한 카본/에폭시 스킨-알루미늄 하니콤 & 발사코어 샌드위치 판넬(두께 : 37mm), 카본/에폭시 스킨-알루미늄 하니콤 코어 샌드위치 판넬(두께 : 57mm, 단열재 포함) 및 카본/에폭시 스킨-알루미늄 하니콤 코어 샌드위치 판넬(두께 : 37mm)에 대한 열관류율 시험을 하였다. 또한 KS F2277 . 2002 (건축용 구성재의 단열성 측정방법-교정열상자법 및 보호열상자법)에 의하여 추가로 알루미늄 스킨-알류미늄 하니콤 샌드위치 판넬들 (두께 : 27mm, 35n1m)과 알루미늄 스킨-포밍 알루미늄 샌드위치 판넬 (두께27mm)에 대한 열관류율 시험을 수행하였다. 본 연구를 통해 면제와 심재사이에 열전달은 실제 단면적이 넓을수록 열관류율이 높았으며, 하이브리드형 복합재 일수록 단열성능이 우수함을 확인하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.97-101
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• 2001

Composite materials have been applied widely in interior panels of buildings and transport vehicles. Recently good fire performance and weight reduction are key issues in the fields. In the present study we investigated effects of processing parameters on the performance of honeycomb sandwich panels, especially peel strength of the panel and fire performance. The processing parameters considered were types of matrix resin, resin contents, panel cure conditions, and surface painting process conditions. The results showed that the higher resin content provides the better peel strength. Controled cure steps are also needed to obtain good pee] strength. Paint processing parameters including base putty thickness and paint drying conditions and paint thickness are important to obtain good paint adhesion and good fire performance.