• The Korean Journal of Rheology
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• v.10 no.2
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• pp.74-81
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• 1998

사출성형품의 설계는 그 내부의 기계적 물성 변화보다는 전통적으로 용도에 부합하 는 형상을 위주로 하여 이루어져 왔기 때문에 설계조건의 개선을 통하여 성능이 우수한 제 품을 얻기까지 많은 시행착오가 요구되고 있다. 그런데 사출성형 실험이나 물성평가 시험을 하기 전에 성형품의 부위별 기계적 물성을 알수있다면 제품의 설계나 금형 설계에 많은 도 움이 될 수 있으므로 최근에 물성 예측을 위한 방법론들의 개발이 다양하게 시도되고 있다. 따라서 본 연구에서는 학습시스템, 사출성형 수치모사와 기계적 물성과의 상관관계를 밝히 는 방법을 만들어 사출물이 제작되기 전에 그들의 기계적 물성을 사출성형 수치모사에서 얻 어진 열적·기계적 이력으로부터 예측하고자 하였다. 이때 성형품의 기계적 물성과 열적· 기계적 이력 사이에는 매우 복잡하고 비선형적인 상관관계를 보이기 때문에 이들 사이를 비 매개변수적으로 연관짓기 위하여 역전파 인공신경망 알고리듬을 사용하였으며 열적·기계적 이력은 사출성형용 수치모사 소프트웨어를 이용하여 구하였다. 학습과정에서 전역최소값에 도달하지 못하는 인공신경망의 문제점을 해결하기 위하여 모멘텀변수와 잡음지수를 포함하 는 일련의 항을 첨가하여 연결가중치를 보정하였다. 그 결과 어떤 초기값에 의하여 학습이 되더라도 전역최소값에 도달하는 것을 확인하였으며 이를 이용하여 다른 사출조건에서 사출 물의 기계적 물성을 잘 예측할수 있었다.

• Tunnel and Underground Space
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• v.25 no.1
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• pp.1-23
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• 2015

In this technical report we summarize the observational data on thermal and mechanical properties of rocks reported by over 70 best published papers. The experimental results reported individually are integrated and presented in tables and figures here, which will provide fundamental data to fairly determine and evaluate the rock properties at the initial design stage of underground structures exposed to high temperature environment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.4
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• pp.429-438
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• 2011

In this paper, experiment of thermal conductivity among thermal properties for CCS insulation material was carried out under the condition ranged from room temperature to cryogenic temperature. CCS insulation system should be sustained under cryogenic temperature($-163^{\circ}C$), and lots of investigations will be conducted how to block the heat to insulation material. CCS components which consist of various materials are especially the main interests, and how the temperature of the entire CCS along the location is should be investigated through these studies. With the experimental thermal properties, the steady state thermal analysis of the entire cargo system was conducted. When the LNG leaked through the insulation system with external impact, temperature distribution and thermal safety of secondary barrier, especially plywood and hull structure, was observed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.4
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• pp.347-355
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• 2014

Thermal problems that are directly related to the lifetime of an electronic device are becoming increasingly important owing to the miniaturization of electronic devices. To solve thermal problems, it is essential to study thermal stability through thermal diffusion and insulation. A honeycomb sandwich plate has anisotropic thermal conductivity. To analyze the thermal deformation and temperature distribution of a system that employs a honeycomb sandwich plate, the thermal and elastic properties need to be determined. In this study, the thermal and elastic properties of a honeycomb sandwich plate, such as thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and shear modulus, are predicted. The properties of a honeycomb sandwich plate vary according to the hexagon size, thickness, and material properties.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.517-518
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• 2011

본 논문에서는 국내 원자력 발전소용 고압케이블의 열화평가를 위해 열적, 화학적 시험을 진행하였다. 최근 설계수명이 종료되는 원자력 발전소와 케이블들에 대한 열화평가 연구가 시작되고 있다. 그러나 현재까지 기초연구 수준에 머물러 있기 때문에 체계적인 열화평가 이루어지고 있지 않다. 따라서 본 논문에서는 국내 원전 고압케이블의 열적, 화학적 시험을 통해 기초 물성자료를 구축하고 열화평가에 이용하기 위해 본 시험을 수행하였다.

• Elastomers and Composites
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• v.49 no.2
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• pp.117-126
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• 2014

Methylene diisocyanate (MDI) was investigated as a novel interfacial modifier to enhance the performances of poly(methyl methacrylate)-modified starch/styrene-butadiene rubber (PMMA-modified starch/SBR) composites. Owing to the formation urethane linkage on one side and ${\pi}-{\pi}$ adhesion on the other side, MDI acted as an intermediated linkage role in the PMMA-modified starch/SBR interfaces, which was evidenced by the morphological, mechanical, dynamic mechanical and thermal decomposition studies. As a result, the presence of MDI significantly improved the mechanical properties and thermal stability of PMMA-modified starch/SBR composites. In addition, the effect of starch concentration on the various performances of the resulted MDI/PMMA-modified starch/SBR composites, such as morphology, vulcanization characteristics, mechanical properties, toluene swelling behavior, and thermal stability were investigated and discussed in detail. The obtained MDI/PMMA-modified starch/SBR composites exhibited superior mechanical properties to carbon black/SBR (CB/SBR) composites, demonstrating the potential use of the renewable starch as a substitute for CB in the rubber compounds.

• Clean Technology
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• v.12 no.1
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• pp.11-18
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• 2006

In this study, aqueous polyurethane dispersion(PUD) was synthesized using polyhexamethylene carbonate glycol (PHMCG) as soft segment, isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as hard segment. Also, polyurethane/clay nanocomposites were prepared by adding pristine montmorillonite (PM) and organically modified clays, C15A and C30B into PUD. The degree of clay dispersion in the nanocomposites was investigated using XRD and the physical and thermal properties were examined through UTM and TGA. These results showed that nanocomposites with C15A gave higher physical and thermal properties than those with C30B or PM. As a result, the properties of nanocomposites were observed to vary depending on the types of clay modifiers and clay contents.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.1-9
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• 2023

Recently, as Synthetic Aperture Radar (SAR), communication, and signal surveillance missions of spacecraft have become more advanced, research has been actively conducted on the deployable large mesh antenna system with excellent storage efficiency compared to the deployment area, and light weight. Deployable Mesh antennae are characterized by an increase in the number of Openings Per Inch (OPI), which is a measure of mesh weaving density as the mission frequency band increases, and this OPI change directly affects the thermal optical properties of the mesh antenna, so research on this is required. In this paper, to verify the thermal relationship between the optical properties of the mesh and antenna reflector, thermal sensitivity analysis between the mesh and the antenna reflector is performed by in-orbit thermal analysis with various optical characteristics of the mesh based on existing overseas research cases. In addition, the temperature gradient effect of the mesh reflector is analyzed.

• Proceedings of the Korean Fiber Society Conference
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• 1999.10a
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• pp.119-122
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• 1999

• Proceedings of the Korean Geotechical Society Conference
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• 1994.03b
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• pp.133-140
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• 1994