• Coupled systems mechanics
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• 제8권6호
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• pp.473-488
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• 2019

The present work is the study of mechanical behavior due to variation of the geometrical parameters in the core of the sandwich honeycomb panel. This study has allowed us to increase or decrease the strains and stresses of the panel, in changing the angle of alveolus, as explained and described below. In taking into consideration the results obtained previously to improve the mechanical properties and increase the adhesion of different parts of the panel, without changing the adhesive, we have conceived two new models, in increasing the contact surfaces in boundary of each part of the panel and giving a conical hexagonal shape in his corp.

• 한국정밀공학회지
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• 제30권11호
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• pp.1203-1210
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• 2013

Korea's first Naro-Science small class satellite was launched by Naro launcher in 2013. The structure of the satellite is mostly composed of aluminum honeycomb and frame. The honeycomb structure is homogenized with asymptotic homogenization method and its mechanical properties were used for the numerical analysis. There have been some difficulties to modeling the honeycomb sandwich panels for FEA. In the present study, the mechanical characteristics of the sandwich panel composite were numerically computed and used for the simulation. This methodology makes it easy to overcome the weakness of modeling of complicated sandwich panels. Both an experiment of vibration test and numerical analyses were conducted simultaneously. The analysis results from the current homogenization were compared with that of experiment. It shows a good agreement on the dynamic responses and certified the reliability of the present methodology when manipulate sandwich panel structure.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권6호
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• pp.554-562
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• 2016

Recently, regulations pertaining to the noise and vibration environment of offshore plants have been strengthened. For example, the NORSOK standards have been applied, which are very strict regulations that are comparable to those applied to passenger ships. Furthermore, the use of porous materials, such as those used in most of the current insulating panels, has been forbidden. Therefore, honeycomb-backed Micro-Perforated Plates (MPPs) are now regarded as next-generation absorber materials. This paper reports the results of parametric studies that were performed using numerical methods to determine the effect of the thickness on the performance of a honeycomb panel and the effect of the perforation ratio on the MPP performance. The numerical results were verified through experiments. Finally, we propose a combined honeycomb/MPP panel where the MPP is placed between upper and lower honeycomb panels and one end surface is also replaced with an MPP.

• Advances in aircraft and spacecraft science
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• 제9권5호
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• pp.377-400
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• 2022

The aim of this work is a numerical comparison (FEM) between lattice pyramidal-core panel and honeycomb core panel for different core thicknesses. By evaluating the mid-span deflection, the shear rigidity and the shear modulus for both core types and different core thicknesses, it is possible to define which core type has got the best mechanical behaviour for each thickness and the evolution of that behaviour as far as the thickness increases. Since a specific base geometry has been used for the lattice pyramidal core, the comparison gives us the opportunity to investigate the unit cell strut angle giving the higher mechanical properties. The presented work considers a detailed FEM modelling of a standard 3-point bending test (ASTM C393/C393M Standard Practice). Detailed FEM modelling addresses to detailed discretization of cores by means of beam elements for lattice core and shell elements for honeycomb core. Facings, instead, have been modelled by using shell elements for both sandwich panels. On lattice core structure, elements of core and facings are directly connected, to better simulate the additive manufacturing process. Otherwise, an MPC-based constraint between facings and core has been used for honeycomb core structure. Both sandwich panels are entirely built of Aluminium alloy. Prior to compare the two models, the FEM sandwich panel model with lattice pyramidal core needs to be validated with 3-point bending test experimental results, in order to ensure a good reliability of the FEM approach and of the comparison. Furthermore, the analytical validation has been performed according to Allen's theory. The FEM analysis is linear static with an increasing midspan load ranging from 50N up to 500N.

• 대한기계학회논문집A
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• 제34권1호
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• pp.55-60
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• 2010

틸팅형 고속열차의 차체에 적용되는 하니컴 복합재 조인트 구조물의 경우 운행중 외팔보형 굽힘하중을 받게된다. 하이브리드 복합재 조인트 구조물에 대한 굽힘시험평가를 수행하기 위해 실제 틸팅열차 차체 구조물에서 조인트부를 절단 채취하여 시험편으로 제작하였다. 굽힘시험결과 시험편의 파괴거동은 정적하중과 피로하중하에서 확연히 달라짐을 보였다. 정적굽힘하중 하에서는 하니컴 코어 영역에서 전단변형과 파괴가 발생하였으며, 피로굽힘하중 하에서는 복합재 표피층과 하니컴 코어층 사이에서 계면분리가 발생하거나, 또는 금속재 언더프레임과의 용접부에서 파괴가 발생하였다. 이러한 파괴거동은 다른 산업분야에서 사용되는 유사한 구조의 하니컴 복합재 조인트 구조물에서도 발생할 수 있기 때문에, 본 실험 결과를 하니컴 복합재 조인트 구조물의 설계변수를 개선하기 위해 이용될 수 있다.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1931-1936
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• 2010

한국형 틸팅열차에는 고속화와 경량화를 위하여 허니콤 복합재가 처음으로 사용된다. 틸팅열차의 측벽은 탄소섬유강화 에폭시층과 접착된 알미늄 허니콤 및 노멕스 허니콤 판재를 주 요소로, 유리면이 적층된 복합 적층재이다. 본 연구에서는 ASTM E2249-02에 근거하여 알미늄 및 노멕스 허니콤 복합 적층재의 층별 인텐시티 투과손실을 측정한다. 질량법칙편차를 이용하여 허니콤 복합재의 중량 대비 차음 성능을 평가하고, 차음 측면에서 알미늄 허니콤 복합재가 기존의 주름강판을 대체할 수 있는지의 가능성을 검토한다. 본 연구를 통하여 얻은 허니콤 복합 적층재의 차음성능 자료는 향후 틸팅 열차의 실내 소음 대책 수립에 활용될 것이다.

• 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.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.273-278
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• 2009

The experimental study is performed to investigate the optimum design of the system dissipating properly heat from the in-situ solar panel installed on site. For this purpose, six 12-Watts panels, which are set at the different conditions of the solar panels contained phase change material, changing the array of the aluminum fin and honeycomb at the back of the panel, are tested. PCM, which has $44^{\circ}C$ melting point, is chosen in this study. In order to enhance the thermal heat from the absorbed heat in PCM, finned aluminum plate is placed. Furthermore, Aluminum honeycomb is imbedded in the back container to find if it would improve the thermal conductivity of PCM. As a result, the solar panel, which is combined with honeycomb and outward fins with PCM instead of placing the fine inward, is showing the best performance in terms of controling panel temperature and efficiency.

• Composites Research
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• 제26권2호
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• pp.116-122
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• 2013

본 연구는 동일한 코어재를 가지는 알루미늄과 유리섬유의 하니컴 샌드위치 판넬의 저속 충격시 발생하는 충격 거동 및 압축 실험을 통하여 압축 강도와 압축 계수를 살펴본다. 저속 충격을 받는 하니컴의 충격 거동을 살펴보기 위하여 중량 낙하식 충격 시험을 실시하며, 충격을 가한 후 데이터 분석 및 현미경을 통하여 전형적인 충격파손모드와 손상정도를 비교 평가하였다. 동일한 충격에너지일 때 유리섬유 하니컴 샌드위치 판넬이 알루미늄 하니컴 샌드위치 판넬보다 최대 하중이 높고, 탄성 에너지가 크며, 충격 강도가 높은 것을 확인할 수 있었다.

• 해양환경안전학회지
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• 제23권7호
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• pp.948-955
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• 2017

현재 해양플랜트용 패널의 주요한 중심재는 다공성재료(미네랄울) 이지만, 뛰어난 차음성능에도 불구하고 환경적인 이유로 이를 대체할 재료가 요구되고 있다. 허니컴 구조는 무게 대비 강도가 우수하여 산업전반에서 많이 쓰이고 있다. 하지만 소음진동 측면에서의 연구는 미미하다. 다공성재료를 대체하기 위한 연구로서 허니컴의 음향학적 연구가 필요하다. 본 논문에서는 허니컴패널을 대칭모드와 비대칭모드의 중첩으로 가정하여 수치해석을 진행하였다. 이러한 이론을 통한 수치해석과 실험결과를 비교하여 수치해석의 신뢰성을 검증하였다. 그리고 수치해석을 통해 허니컴패널의 차음특성을 연구하고 중심재로서의 가능성을 평가하였다. 패널두께를 키울수록 일치주파수가 저주파수로 이동하였다. 셀사이즈와 셀벽의 사이각이 감소함에 따라 차음성능이 개선되었고, 셀벽두께의 경우 증가할수록 차음성능이 향상되었다.