• Title/Summary/Keyword: Material properties

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A Study on the Surface Properties of Polymer Insulators for Improving Electrical Insulation Performance (전기 절연성능 향상을 위한 폴리머 애자의 표면 특성 연구)

  • Park, Yong Seob;Bae, Jae Sung;Hong, Byungyou;Lee, Jae Hyeong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.1
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    • pp.63-67
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    • 2021
  • In this paper, we investigated the surface properties of polymer insulators to improve electrical insulation performance. First, after washing the polymer insulator in various ways, its contact angle was increased, thereby improving the hydrophobic properties and electrical insulation properties. In addition, TiO2 thin films, which have been used as a photocatalytic material and have been applied to the polymer insulator surface of to enhance the surface and electrical insulating properties. For the sputtering method, the contact angle after coating the TiO2 thin film increased with increasing RF power, but it was lower compared to that before coating, indicating that the hydrophobic properties of the surface were slightly deteriorated. Consequently, the electrical properties of the polymer-insulating material were maintained or improved after the TiO2 thin-film coating.

A Study on Wearing Sensations of Girls'High School Uniforms Based on Elasticity(1) -Focusing on Mechanical Properties and Insulation- (신축성에 따른 여고생 교복의 착용감에 관한 연구(제1보) -역학적 특성과 보온성에 관하여-)

  • 민경혜;류덕환
    • Journal of the Korean Society of Clothing and Textiles
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    • v.27 no.5
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    • pp.545-553
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    • 2003
  • A good school uniform leads students to good behavior and have them enjoy desirable school life. Therefore a better fabric for girls' high school uniform suggested through two series of studies; first, examined the various aspects of current uniforms. Second, made a new fabric for uniform considering elasticity for activity and comfortableness, and compared its characteristics with those of the current uniforms. The results are as follows; 1 Most of students wanted uniforms considering elasticity for activity and wearing. 2. The measurement of the elasticities of the uniform materials showed that the material which was made using the elastic material was more elastic than the currently used material by 42.12% in summer material and 20.05% in winter one. 3. The analysis using the combination of the values of mechanical properties showed that the elastic material was better in the wearing, tactile senses, and drape properties than the current material, even though it was a little worse in shape-stability. 4. To compare the thermal insulation, clo values were measured. For winter uniform, the elastic material was better than the current one in keeping warm. However, This study did not find any big difference between summer uniform materials.

The Effects of Various Cement Type and Compositions on the Material Properties of high Strength Concrete (시멘트 특성의 변화가 고강도콘크리트의 재료특성에 미치는 영향)

  • 백상현;이종열;엄태선;임채용;안광원
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.47-52
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    • 2000
  • Recently, it is very necessary the development of the manufacturing techniques for high strength concrete(HSC) for the large-scale size and good quality of civil structure. But, the manufacture and quality control of HSC of which shrinkage, heat of hydration and workability at construction filed are considered, is very difficult due to its low water-cement ratio and high quantity of unit cement content. In the present study, we tried to know and assess the influences of chemical and physical properties of cement on the material properties of HSC. We analyzed basic properties of 4 kinds of cement whose chemical and physical properties are different each other through various tests such as chemical analysis and mortal test. Also, we performed the assessment of the material properties of HSC for each dement by the test for the conditions of same mix design and similar compressive strength. From the results in the study, the assessment of the important quality factors of cement influencing the properties of HSC may be utilized to quality control of applied cement to manufacture the HSC of high quality.

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Temperature, Electric Field, Pressure Dependency and Dielectric properties on the interface between XLPE and EPDM (XLPE와 EPDM의 계면에 따른 유전특성과 온도, 전계, 압력의존성)

  • 김동식;박대희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.109-111
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    • 1997
  • In this paper, we have evaluated temperature, electric field, Pressure dependency and dielectric properties of EPDM XLPE and EPDM/XLPE\`s interface. Temperature dependency of EPDM had great influence with dielectric properties, but pressure and applied voltage of EPDM had no effect on dielectric properties. Dielectric properties of XLPE were influenced by not only temperature but also pressure and applied voltage. We knowed that dielectric properties of EPDM/XLPE were trended toward tendency of those of EPDM

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Recalculation Research of Material properties for CFRP FEM Non-linear Analysis (CFRP FEM 비선형 해석을 위한 물성치 재확립에 관한 연구)

  • Kim, Jung-Ho;Kim, Chi-Joong;Cha, Cheon-Seok;Kim, Ji-Hoon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.4
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    • pp.608-612
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    • 2012
  • To reduce these costs and time by finite element analysis program has been much research (3~4). At virtual CAE program as like Abaques, Ansys, Ls-dyna and Nastran, the input data of material is got bellow coupon test. In case of carbon composite, it is also put in lamina/laminate properties. There have big problem. If you want to simulate FW(filament winding or wind blade) how do you input material data. Each area of FW is different stacking conditions. It's too hard that each area is tested for inputting lamina or laminate properties. The composite structure increasing load is applied occurred as the matrix dependence of the crack-induced nonlinearity and nonlinear mobility appears since the initial damage. And uni-direction for this research applies the theory to have been confined to. On this study, we are going to get basically fiber properties and matrix than carbon composite properties for simulating according stacking method by GENOA-MCQ. It is help to simulate easily composite material. Also Calculate the matrix nonlinear for simulating non-linear.

Thermo-mechanically induced finite element based nonlinear static response of elastically supported functionally graded plate with random system properties

  • Lal, Achchhe;Jagtap, Kirankumar R.;Singh, Birgu N.
    • Advances in Computational Design
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    • v.2 no.3
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    • pp.165-194
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    • 2017
  • The present work proposes the thermo mechanically induced statistics of nonlinear transverse central deflection of elastically supported functionally graded (FG) plate subjected to static loadings with random system properties. The FG plate is supported on two parameters Pasternak foundation with Winkler cubic nonlinearity. The random system properties such as material properties of FG material, external loading and foundation parameters are assumed as uncorrelated random variables. The material properties are assumed as non-uniform temperature distribution with temperature dependent (TD) material properties. The basic formulation for static is based on higher order shear deformation theory (HSDT) with von-Karman nonlinear strain kinematics through Newton-Raphson method. A second order perturbation technique (SOPT) and direct Monte Carlo simulation (MCS) are used to compute the nonlinear governing equation. The effects of load parameters, plate thickness ratios, aspect ratios, volume fraction, exponent, foundation parameters, and boundary conditions with random system properties are examined through parametric studies. The results of present approaches are compared with those results available in the literature and by employing direct Monte Carlo simulation (MCS).

Crack Analysis of Piezoelectric Material Considering Bounded Uncertain Material Properties

  • Kim, Tae-Uk;Shin, Jeong-Woo
    • International Journal of Aeronautical and Space Sciences
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    • v.4 no.2
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    • pp.9-16
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    • 2003
  • Piezoelectric materials are widely used to construct smart or adaptive structures. Although extensive efforts have been devoted to the analysis of piezoelectric materials in recent years, most researches have been conducted by assuming that the material properties are fixed and have no uncertainties. Intrinsically, material properties have a certain amount of scatter and such uncertainties can affect the performance of component. In this paper, the convex modeling is used to consider such uncertainties in calculating the crack extension force of piezoelectric material and the results are compared with the one obtained via the Monte Carlo simulation. Numerical results show that crack extension forces increase when uncertainties considered, which indicates that such uncertainties should not be ignored for reliable lifetime prediction. Also, the results obtained by the convex modeling and the Monte Carlo simulation show good agreement, which demonstrates the effectiveness of the convex modeling.

Damping Properties of the Spray Type Vibration Reduction Material for the Use of the Automotive Interior Parts (자동차 내장용 분무형 제진재의 제진특성)

  • 윤주호;윤여성;김영명;김의용;김종수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.138-146
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    • 2002
  • The new type of vibration reduction material far an automotive interior, which is spray-type liquid material, is developed in this study The new material has better damping property and lower mass density than other damping materials, for example asphalt sheet. It can be sprayed by an automatic robot, so it is expected to improve productivity and cut down manpower. And it solves a poor adhesion problem and makes an automotive to be lightweight by optimizing spray process. So, It is a next generation automotive vibration reduction material. In this paper, the chemical process for making the new damping materials is described. And then, the damping properties of the vibration reduction materials are analyzed by modal testing of damping treatment specimens. The new vibration reduction materials have good damping properties than asphalt sheet in the experimental results.

Microstructures and Mechanical Properties of AZ31-(0~0.5%)Ca alloys (AZ31-(0~0.5)%Ca 합금의 미세조직과 기계적 성질)

  • Jun, Joong-Hwan;Park, Bong-Koo;Kim, Jeong-Min;Kim, Ki-Tae;Jung, Woon-Jae
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.5
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    • pp.299-304
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    • 2004
  • Influence of Ca addition on microstructure and room temperature mechanical properties has been studied for AZ31(Mg-3%Al-1%Zn-0.2%Mn)-(0~0.5)%Ca wrought alloys, based on experimental results from metallography, X-ray diffractometry and mechanical tests. Yield strength, ultimate tensile strength and hardness of the alloys increased remarkably with increasing Ca content, whereas elongation was deteriorated continuously. Microstructural examination revealed that Ca addition efficiently refined grains of ${\alpha}$(Mg) phase and that some of the Ca dissolved in ${\beta}(Mg_{17}Al_{12})$ precipitates. The former and the latter facts are thought to be responsible for improved strength and loss of ductility of the AZ31+Ca wrought alloys, respectively.