• Title/Summary/Keyword: Hybrid Composite Materials

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Technology and Application of Hybrid Insulation Film for Electric Magnet Wire (하이브리드 절연필름의 전동기권선 적용 특성 연구)

  • Han, Se-Won;Han, Dong-Hee;Kang, Dong-Phil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.210-211
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    • 2006
  • This study presents the technology and application of hybrid insulation film for electric magnet wire. In order to make the high efficient motor with high space factor, it is necessary to develop a self-lubrication heat-resistant insulation film that can be used when the space factor 70% or more. A key to achieving high windability is to increase the lubricity and bonding strength of vanish, which for a magnet wire generally determines the mechanical scratches characteristics. Effective ways to reduce scratches include improving insulation film prepared by organic and inorganic hybrid synthesis methods.

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A Study on the Evaluation of the Failure for Carbody Structures made of Laminated Fiber-Reinforced Composite Materials Using Total Laminate Approach (전체 적층판 접근법을 이용한 섬유강화 적층 복합재 차체 구조물의 파손평가 연구)

  • 신광복;구동회
    • Composites Research
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    • v.17 no.1
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    • pp.18-28
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    • 2004
  • In order to evaluate the strength of carbody structures of railway rolling stock made of laminated fiber-reinforced composite materials, total laminate approach was introduced. Structural analyses were conducted to check the basic design of hybrid composite carbody structures of the Korean Tilting Train eXpress(TTX) with the service speed of 180km/h. The mechanical tests were also conducted to obtain strengths of composite laminates. The results show that all stress components of composite carbody structures are inside of failure envelopes and total laminate approach is recommended to predict the failure of hybrid composite carbody structures at the stage of the basic design.

Prediction of Spring-back for GFR/CFR Unsymmetric Hybrid Composites (유리섬유/탄소섬유 강화 비대칭 하이브리드 복합재의 스프링 백 예측)

  • Jung, Woo-Kyun;Ahn, Sung-Hoon;Won, Myung-Shik
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.158-161
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    • 2005
  • The fiber-reinforced composite materials have been advanced for various applications because of its excellent mechanical and electromagnetic properties. On their manufacturing processes, however, thermo-curing inherently produces the undesired thermal deformation mainly from temperature drop from the process temperature to the room temperature, so called spring-back. The spring-back must be removed to keep the precision of designed shape. In this research, the spring-back of {glass fiber / epoxy}+{carbon fiber / epoxy} unsymmetric hybrid composites were predicted using Classical Lamination Theory (CLT), and compared with the experimental data. Additionally, using finite element analysis (ANSYS), the predicted data and experimental data were compared. The predicted values by CLT and ANSYS were well matched with experimental data.

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Effect of Water Absorption on the Tensile Properties of Carbon-Glass/Epoxy Hybrid Composite in Low Temperature (탄소-유리/에폭시 하이브리드 복합재의 저온 인장 특성에 미치는 수분의 영향)

  • Jung, Hana;Kim, Yonjig
    • Korean Journal of Metals and Materials
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    • v.50 no.10
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    • pp.729-734
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    • 2012
  • This study investigated the effect of water absorption on the tensile properties of carbon-glass/epoxy hybrid composites at room temperature and $-30^{\circ}C$. To investigate the effect of the position of glass fabric in the hybrid composite on the tensile properties, the stacking pattern of the fiber fabrics for reinforcing was created in three different ways: (a) glass fabrics sandwiched between carbon fabrics, (b) carbon fabrics sandwiched between glass fabrics and (c) alternative layers of carbon and glass fabrics. They were manufactured by a vacuum-assisted resin transfer molding (VARTM) process. The results showed that there was surprisingly little difference in tensile strength at the two different temperatures with dry and wet conditions. However, the water absorption into the hybrid system affected the tensile properties of the hybrid composites at RT and $-30^{\circ}C$. When the glass fabrics were at the outermost layers, the hybrid composite had the lowest tensile properties. This is attributed to the fact that the composite had a relatively high water absorption rate.

Development of a Composite Rotor for Flywheel Energy Storage System (플라이휠 에너지 저장 장치용 복합재 로터 개발)

  • Kim, Myung-Hun;Han, Hun-Hee;Kim, Jae-Hyuk;Kim, Seong-Jong;Ha, Seong-Gyu
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.169-172
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    • 2005
  • A flywheel system is an electromechanical energy storage device that stores energy by rotating a rotor. The rotating part, supported by magnetic bearings, consists of the metallic shaft, composite rims of fiber-reinforced materials, and a hub that connects the rotor to the shaft. The delamination in the fiber wound composite rotor often lowered the performance of the flywheel energy storage system. In this work, an advanced hybrid composite rotor with a split hub was designed to both overcome the delamination problem in composite rim and prevent separation between composite rim and metallic shaft within all range of rotational speed. It was analyzed using a three-dimensional finite clement method. In order to demonstrate the predominant perfom1ance of the hybrid composite rotor with a split hub, a high spin test was performed up to 40,000 rpm. Four radial strains and another four circumferential strains were measured using a wireless telemetry system. These measured strains were in excellent agreement with the FE analysis. Most importantly, the radial strains were reduced using the hybrid composite rotor with a split hub, and all of them were compressive. As a conclusion, a compressive pressure on the inner surface of the proposed flywheel rotor was achieved, and it can lower the radial stresses within the composite rotor, enhancing the performance of the flywheel rotor.

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Electrical properties of polyethylene composite films filled with nickel powder and short carbon fiber hybrid filler

  • Mironov, V.S.;Kim, Seong Yun;Park, Min
    • Carbon letters
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    • v.14 no.2
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    • pp.105-109
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    • 2013
  • Effects of the amount of nickel powder (Ni) in Ni-carbon fiber (CF) hybrid filler systems on the conductivity(or resistivity) and thermal coefficient of resistance (TCR) of filled high density polyethylene were studied. Increases of the resistivity and TCR with increasing Ni concentration at a given hybrid filler content were observed. Using the fiber contact model, we showed that the main role of Ni in the hybrid filler system is to decrease the interfiber contact resistance when Ni concentration is less than the threshold point. The formation of structural defects leading to reduced reinforcing effect resulted in both a reduction of strength and an increase of the coefficient of thermal expansion in the composite film; these changes are responsible for the increases of both resistivity and TCR with increasing Ni concentration in the hybrid filler system.

Torsional Fatigue Characteristics of Aluminum/Composite Co-Cured Shafts with Axial Compressive Preload (축예하중을 가한 알루미늄/복합재료 동시경화 샤프트의 비틀림 피로 특성)

  • Kim, Jong-Woon;Hwang, Hui-Yun;Lee, Dai-Gil
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.183-186
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    • 2003
  • Long shafts for power transmission should transmit torsional load with vibrational stability. Hybrid shafts made of unidirectional fiber-reinforced composite and metal have high fundamental bending natural frequency as well as high torque transmission capability. However, thermal residual stresses due to the coefficient difference of thermal expansion of the composite and metal are developed so that the high residual stresses decrease fatigue resistance of the hybrid shafts, especially at low operating temperatures. In this work, axial compressive preload was given to the shaft in order to change the residual stresses. Static and fatigue torsional tests were performed and correlated with stress analyses with respect to the preload and service temperature.

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Impact Properties of Glass/Kevlar Hybrid Composites (유리/케블라 하이브리드 구조로 강화된 복합재료의 충격 거동)

  • Joo, Ki-Ho;Ryou, Han-Sun;Chung, Kwan-Soo;Kang, Tae-Jin
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.191-194
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    • 2005
  • Impact properties of glass/Kevlar hybrid composites which have 3-D braided structures were studied. Results were compared to those of composites made of only glass fibers where the same epoxy resin were used as matrix. Absorbed impact energies evaluated through the combination of the data from the impact tester and high speed camera were compared to each other. In order to see the difference between the damaged area distribution CCD camera captures were performed.

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Geometrical Modeling for Hybrid 3-D Braided Composites (하이브리드 삼차원 브레이딩 복합재료의 기하학적 모델링)

  • 한문희;강태진;윤재륜
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.67-70
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    • 2003
  • To develop an effective geometric modeling is essential in order that precise mechanical properties and the geometrical properties of the 3-D braided composites can be estimated. RVE(representative volume element) was adopted fur geometrical modeling. RVE consisted of IC(inner unit cell), ISUC(interior surface unit cell) and ESUC(exterior surface unit cell). The whole geometrical model fur hybrid 3-D braided composites was developed.

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Machinability Evaluation of Hybrid Ti2 Ceramic Composites with Conductivity in Micro Electrical Discharge Drilling Operation (전도성을 가지는 하이브리드 Ti2AlN 세라믹 복합체의 마이크로 방전드릴링에서 가공성 평가)

  • Heo, Jae-Young;Jeong, Young-Keun;Kang, Myung-Chang;Busnaina, Ahmed
    • Journal of Powder Materials
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    • v.20 no.4
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    • pp.285-290
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    • 2013
  • $Ti_2AlN$ composites are a laminated compounds that posses unique combination of typical ceramic properties and typical metallic(Ti alloy) properties. In this paper, the powder synthesis, SPS sintering, composite characteristics and machinability evaluation were systematically conducted. The random orientation characteristics and good crystallization of the $Ti_2AlN$ phase are observed. The electrical and thermal conductivity of $Ti_2AlN$ is higher than that of Ti6242 alloy. A machining test was carried out to compare the effect of material properties on micro electrical discharge drilling for $Ti_2AlN$ composite and Ti6242 alloy. Also, mixture table as a kind of tables of orthogonal arrays was used to know how parameter is main effective at experimental design. Consequently, hybrid $Ti_2AlN$ ceramic composites showed good machining time and electrode wear shape under micro ED-drilling process. This conclusion proves the feasibility in the industrial applications.