• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.262-265
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• 2007

Metallic sandwich plates constructed of two face sheets and low relative density cores have lightweight characteristics and various static and dynamic load bearing functions. To predict the formability and performance of these structured materials, a computationally efficient FE-analysis method incorporating virtual equivalent projected model has been newly introduced for analysis of metallic sandwich plates. Two dimensional models using the projected shapes of 3D structures have the same equivalent elastic-plastic properties with original geometries including anisotropic stiffness, yield strength and linear hardening function. The projected shapes and virtual properties of the virtual equivalent projected model have been estimated analytically with the same equivalent properties and face buckling strength of 3D pyramidal truss core.

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

Experimental investigation on heat transfer ratio was firstly performed with three types of sandwich panels such as the Carbon/Epoxy Skin-Aluminum Honeycomb and Balsa Core Sandwich Panel of 37mm thickness, the Carbon/Epoxy Aluminum Skin-Honeycomb Core Sandwich Panel of 57mm thickness (including insulator) and the Carbon/Epoxy Skin-Aluminum Honeycomb Core Sandwich Panel of 37mm thickness based on the KS F 2278:2003(Insulation test method of windows). In additional to this investigation, experimental tests were also done for evaluation of heat transportation ratio with the Aluminum Skin- Aluminium Honeycomb Sandwich Panels of 27mm and 35mm thickness, and Aluminum Skin-Foaming Aluminum Sandwich Panel of 27mm thickness by the KS F2277:2002 (Insulation measuring method of construction component-Calibration heat box method or protective heat box method). In this study, it was found that the larger net heat transfer cross sectional area between the skin and the sandwich core is given, the higher heat transportation ratio occurs. It was also found that the hybrid type insulation had better insulation characteristics compared to the non-hybrid type insulation.

• The magazine of the Korean Society for Advanced Composite Structures
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• 제5권4호
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• pp.29-42
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• 2014

• Fire Science and Engineering
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• 제23권1호
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• pp.33-39
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• 2009

In this study, the combustion properties, which are called the reaction-to-fire's performance, of sandwich panels were tested and analyzed according to both ISO 5660 (cone calorimeter method) and EN 13823 (SBI). Several variables including ignition time, mass loss, heat release rate, smoke production rate and $O_2$ density about four sandwich panels and four core materials (thermal insulation material) were evaluated. Combustion properties' similarity and difference of sandwich panels and core materials were compared by materials and test methods respectively. Finally test results were evaluated by Japanese standard building code, National Building code of Canada and EN 13501-1 as well.

• Journal of the Korean Society for Railway
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• 제15권2호
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• pp.97-103
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• 2012

Composite honeycomb sandwich plate is light and strong. It is easy to produce. It began to be applied to the bodyshell of rolling stock. Generally, weight saving amounts to 27%. However, the material cost of it is much higher than that of aluminum extrusion profile, which prevents popular use of it for bodyshell. In this paper, manufacturing processes of two light materials were compared to investigate cost impact. After cost breakdown was defined, economics of two materials was analyzed using the previous cost data. Easy production of composite bodyshell could compensate for higher material cost. Mass production of composite bodyshell can make the equipment cost lower for the composite bodyshell so that it may have strong competitiveness to the aluminum bodyshell. Operational energy saving due to weight reduction was also presented referring to the actual statistical data in a metro line.

• Journal of Food Hygiene and Safety
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• 제22권1호
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• pp.45-51
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• 2007

The Collected 70 samples from 5 sandwich shops were analysed for the pathogenic bacteria such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus. As a result of Listeria monocytogenes and Saphylococcus aureus were detected in 1 sample, 11 samples, respectively. However, Escherichia coli O157:H7 and Salmonella spp. were not detected in anywhere. The antibiotics test of isolated bacteria was pelformed by the disk diffusion method from NCCLS. The resistance rate of Listeria monocytogenes isolates was confirmed 38.5% to 10 species such as Am, B, P, and Va for antibiotics of 26 species. MRSA was determinated 4 strains in S. aureus isolates. The resistance pattern of Staphylococcus aureus isolates were confirmed 36.4% to P Am OX B K E CXM, 18.2% to P Am B K E CXM B, 9.1% to P Am B K, 27.3% to P Am B, and 9.1% to Te B Nb. Therefore, continuous surveillance and monitoring for antibiotic resistance strains are demanded for prevention of increases in multiple antibiotic resistance strains.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1301-1302
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• 2011

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제16권1호
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• pp.239-244
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• 2016

The polarization characteristics of polarization-insensitive directional coupler based on double sandwiched rib-type and curved waveguides are explored in detail by using conformal transformation method (CTM) and longitudinal modal transmission-line theory(L-MTLT). To obtain the polarization-insensitive condition of polarization-insensitive curved directional coupler(PI-CDC), the coupling length and coupling efficiency according to the inner radius of PI-CDC are analyzed for quasi-TE and quasi-TM modes. The numerical results show that the PI-CDC with a few micrometer scales can be realized by properly choosing the curvature and structural and material parameters of double sandwiched layers. Furthermore, the mode profiles propagating through PI-CDC are evaluated, and the influence on coupler performance has been investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.702-705
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• 2005

Metallic sandwich plates with Inner dimpled shell subjected to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high quality precision and bonded with same material skin sheets by resistance welding or adhesive bonding process. Optimized shape of inner dimple is a hemispherical shell to minimize weight without failure, including face yielding, face buckling and inner dimple buckling. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times than solid plates with same strength

• Journal of KSNVE
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• 제5권4호
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• pp.577-583
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• 1995

The sandwich type piezoelectric resonator is widely used for the acoustic sources of underwater acoustic transducers, whose important design parameters are shapes, materials, dimensions and supporting methods. Practical design method of resonators consists of manufacturing, experiments and modification so that it requires much time and expenses. In this study, an analytical design method of sandwich type piezoelectric resonators is presented based on the nonlinear optimization technique. The proposed method is applied to the design of an example resonator model in order to maximize the output powers. For the investigation of performance according to the division and their electrical connection, three types of resonators are manufactured. In addition, their dynamic characteristics such as electrical admittance and transmitting voltage response are measured and compared.