• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.96-101
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• 2007

A new metallic sandwich panel with a quasi-Kagome truss core subjected to bending load has been analyzed. First, equations of the failure loads corresponding to the eight failure modes are presented. Then, non-dimensional forms of the equations are derived as functions of three geometric variables, one material parameter (yield strain), one load index and one weight index. Failure maps are presented for a given weight index. By using the dimensionless forms of equations as the design constraints, two kinds of optimization are performed. One is based on the weight, that is, the objective function, namely, the dimensionless load is to be maximized for a given weight. Another is based on the load, that is, the dimensionless weight is to be minimized for a given load. The results of the two optimization processes are found to agree each other. The optimized geometric variables are derived as a function of given weights or failure loads. The performance of the quasi-Kagome truss as the core of a sandwich panel is evaluated by comparison with those of honeycomb cored and octet truss cored panels

• 대한기계학회논문집A
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• 제31권9호
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• pp.943-950
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• 2007

A new metallic sandwich panel with a quasi-Kagome truss core subjected to bending load has been analyzed. First, equations of the failure loads corresponding to the eight failure modes are presented. Then, non-dimensional forms of the equations are derived as functions of three geometric variables, one material parameter (yield strain), one load index and one weight index. Failure maps are presented for a given weight index. By using the dimensionless forms of equations as the design constraints, two kinds of optimization are performed. One is based on the weight, that is, the objective function, namely, the dimensionless load is to be maximized for a given weight. Another is based on the load, that is, the dimensionless weight is to be minimized for a given load. The results of the two optimization processes are found to agree each other. The optimized geometric variables are derived as a function of given weights or failure loads. The performance of the quasi-Kagome truss as the core of a sandwich panel is evaluated by comparison with those of honeycomb cored and octet truss cored panels.

• 한국화재소방학회논문지
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• 제24권4호
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• pp.47-54
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• 2010

본 연구에서는 창고 화재 사고의 위험성을 파악하기 위해서 중규모 실물 화재 실험 장비인 룸코너 시험기(Room Corner Tester)를 통해 구축된 단위 구성품의 화재 특성 DB를 바탕으로 화재에 취약할 것으로 판단되는 의류 창고를 실험 모델로 구성하여 실물 화재실험 장비인 라지 스케일 칼로리미터(Large Scale Calorimeter)에서 실물 화재실험을 실시하였다. 창고 모델의($3m{\times}3m{\times}2.4m$) 벽체는 불연등급의 그라스울과 일반 스티로폼 샌드위치 패널로 구성하였다. 실험결과 최대 열방출률은 그라스울 샌드위치 패널 창고모델에서 5MW, 스티로폼 샌드위치 패널 창고모델에서 11MW를 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.77-78
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• 2022

To improve the fire vulnerability of the organic insulation sandwich panel core, which is the main culprit of the large-scale fire disaster, an experiment was conducted to examine the thermal conductivity properties of the core material mixed with the organic insulation material EPS Bead and the inorganic insulation material glass wool. As the Additional ratio of glass wool increased, the thermal conductivity decreased, and it was determined that the replacement of glass wool of 3% or more had little effect on the decrease in thermal conductivity. In addition, it can be seen that the most ideal thermal conductivity is exhibited when 1% Replacement ratio of EPS and 3% glass wool are added. The core material of such organic and inorganic insulation materials is judged to be a core material that can compensate for the fire vulnerability of existing insulation materials. Therefore, in order to determine whether it is used as a core material for sandwich panels, additional studies such as fire resistance experiments and sound absorption experiments are needed in the future.

• Steel and Composite Structures
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• 제44권4호
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• pp.519-529
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• 2022

Sandwich structures with the superior mechanical properties such as high stiffness and strength-to-weight ratio, good thermal insulation, and high energy absorption capacity are used today in aerospace, automotive, marine, and civil engineering industries. These structures are composed of moderately stiff, thin face sheets that withstand the majority of transverse and in-plane loads, separated by a thick, lightweight core that resists shear forces. In this research, the finite element technique is used to simulate a sandwich panel with a truss core under axial compressive stress using ABAQUS software. A review of past experimental studies shows that the bondline between the core and face sheets plays a vital role in the critical failure load. Therefore, this modeling analyzes the damage initiation modes and debonding between face sheet and core by cohesive surface contact with traction-separation model. According to the results obtained from the modeling, it can be observed that the adhesive stiffness has a significant influence on the critical failure load of the specimens. To achieve the full strength of the structure as a continuum, a lower limit is obtained for the adhesive stiffness. By providing this limit stiffness between the core and the panel face sheets, sudden failure of the structure can be prevented.

• 한국농촌건축학회논문집
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• 제20권1호
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• pp.27-36
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• 2018

At present, the elderly population in Korea is 14% of the total population and then We has entered an the society of advanced age. Along with this, elderly people with dementia and palsy are also increasing. The demand for elderly nursing homes for elderly people with severe diseases such as dementia and stroke is also increasing, and the existing buildings are being secured by Conversion of existing buildings. However, it is difficult to evacuate and fire due to the out of date of buildings by Conversion of existing buildings. For example, there is a fire in the Indukukwon, Pohang City and Hyosung Geriatric Hospital, Jangseong in Korea, which have changed the use of existing buildings. Many elderly people died in a night fire. It was because of the sandwich panel walls and PVC flooring material produced toxic gas instantly. In this study, we investigated the nursing home that changing the use and established fire prevention of human injury and countermeasure of evacuation. First, the sandwich panels which leading to deaths due to the toxic gas were installed in most nursing home. We recommend the RC, the masonry wall, and the glass fiber panel instead of the sandwich panels, In addition, the PVC flooring is most used in nursing home, the flooring material is considered such as the building stones, the tile, and the yellow soil closing instead of the PVC flooring. Second, we investigated the installation status of fire fighting equipment. As a result, the automatic-emergency open&shut equipment, the smoke ventilator and the evacuation slide were rarely installed. In order to secure the golden time in case of fire and to prevent the asphyxia caused by the toxic gas, the law should be amended to install the equipment.

• 품질경영학회지
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• 제43권3호
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• pp.299-312
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• 2015

Purpose: This paper analyzes the phenomenon on the degradation of the electrical performance by the pressure in the manufacturing process of sandwich type radomes. Methods: This paper consists of two steps to analyze the relation between the electrical performance and the pressure. First, the thickness of the core of the flat panels which were fabricated with different pressure was measured with the microscope, and then the electrical performance of the flat panels was analyzed with simulation and experiment. Based on the results of the electrical performance and the measured thickness with respect to the flat panels, the relation between the electrical performance and the applied pressure in the manufacturing process was analyzed. Results: The simulated and measured results with respect to the flat panel shows that the high pressure results in the nonuniform thickness of the core, which is applied to the radome fabrication. As a result, the degradation of the electrical performance occurs because the unintended scattered field is generated as the electromagnetic wave transmits (or impinges upon) the radome. Furthermore, we observed that the electrical performance of both the flat panel and the radome got worse as the high pressure was applied. Conclusion: Through simulation and experiment, therefore, it is demonstrated that for the high pressure in the manufacturing process the nonuniform thickness of the core increases and results in the degradation of the electrical performance of the radome.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.262-267
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• 2008

1970년대부터 고도의 산업발전을 이루기 시작한 국내 건설현장에서 저렴한 공사비용 및 간편한 시공성 등을 장점으로 샌드위치패널을 활용한 건축물이 급격하게 증가하는 실정이다. 하지만 샌드위치 패널의 시공을 담당하는 기업들은 대형 건설기업보다 중소건설업체에서 시공하기 때문에 생산성 향상을 위한 연구가 부족한 상황이다. 본 연구는 샌드위치패널공사현장을 실사하여 작업조별 작업싸이클을 분석하고 Web-Cyclone을 이용한 모델링을 구축하여, 각 작업조별 생산성 및 공사금액을 분석하였다. 이를 활용하여 샌드위치패널공사의 작업조 생산성 정보를 상대적으로 연구가 부족한 국내 중 소규모 전문건설업체들이 자신들의 현장 특성에 적합한 샌드위치패널공사의 생산성 및 공사금액을 예측 및 적용할 수 있을 것이다. 또한 본 연구에서 작성한 모델링을 기반으로 유사한 공정에 대하여 시뮬레이션을 모델링화하는데 적용될 수 있을 것으로 예상된다.

• 한국재난정보학회 논문집
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• 제15권1호
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• pp.98-108
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• 2019

연구목적:본 연구는 화재 시 샌드위치패널 구조 창고의 벽 천장접합부 방호를 위한 스프링클러 성능확인 실험을 목적으로 한다. 연구방법: 현장조사결과를 기반으로 창고의 공간규격과 가연물을 선정하고 벽 코너 및 헤드 직하부에서의 방호실험을 수행하고 결과를 분석하였다. 연구결과:벽 코너 화재 시나리오에 대해서 K-80 폐쇄형 스프링클러헤드의 작동으로 샌드위치 패널의 착화 및 접합부 손상이 방지됨을 확인하였다. 결론:샌드위치패널 심재로의 착화 및 연소방지를 통한 화세제어로 이를 가정한 소방대의 소화 및 구조활동을 위한 표준진압대책이 마련되어야 한다.

• Steel and Composite Structures
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• 제32권5호
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• pp.671-686
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• 2019

Active control of solar panels with honeycomb core and carbon nanotube reinforced composite (CNTRC) facesheets for smart structures using piezoelectric patch sensor and actuator to reduce the amplitude of vibration is a lack of the previous study and it is the novelty of this research. Of active control elements are piezoelectric patches which act as sensors and actuators in many systems. Their low power consumption is worth mentioning. Thus, deriving a simple and efficient model of piezoelectric patch's elastic, electrical, and elastoelectric properties would be of much significance. In the present study, first, to reduce vibrations in composite plates reinforced by carbon nanotubes, motion equations were obtained by the extended rule of mixture. Second, to simulate the equations of the system, up to 36 mode shape vectors were considered so that the stress strain behavior of the panel and extent of displacement are thoroughly evaluated. Then, to have a more acceptable analysis, the effects of external disturbances (Aerodynamic forces) and lumped mass are investigated on the stability of the system. Finally, elastoelectric effects are examined in piezoelectric patches. The results of the present research can be used for micro-vibration suppression in satellites such as solar panels, space telescopes, and interferometers and also to optimize active control panel for various applications.