• Title/Summary/Keyword: Composites Material

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능동 화이버 복합재의 모델링 및 적용 연구 (Modeling and Application of Active Fiber Composites)

  • 하성규;이영우;김영호
    • 대한기계학회논문집A
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    • 제25권8호
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    • pp.1261-1268
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    • 2001
  • Effective material properties of active fiber composites with interdigitated electrodes are derived as a function of the fiber volume fraction. For the purpose of applying the rule of mixture, three unit cell models are introduced; each for the deformation and stress continuities in the out of plane and in-plane directions, and the continuity of the electrical displacement in the longitudinal direction. Derived effective material properties are compared with the results by the finite element method; good agreements are observed between them. As an application, the electromechanical behavior of the angle ply laminates with the active fiber layers bonded on the top and bottom surfaces are investigated; the angle of piezoelectric fiber to maximize the twisting curvature is obtained using the present model.

Epoxy/Annealing $SiO_2$ Composites의 충진함량에 대한 저 유전특성 (Low Dielectric Properties of Epoxy/Annealing $SiO_2$ Composites for Filler Contents Variation)

  • 박재준;안준오;윤종현
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.224-225
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    • 2007
  • The Low dielectric properties of epoxy/Annealing $SiO_2$ composites using Annealing new material of nanosized amorphous particles were investigated as function frequency, temperature and filler contents composition. The dielectric constant decrease with increasing frequency and also increase with increasing ambient temperature. The dielectric constant decrease with increase annealing filler contents for epoxy base. The result of x-ray diffraction could obtained single crystal of annealing $SiO_2$ from 500nm amorphous $SiO_2$ powder.

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균질화기법을 이용한 WFC의 등가물성치 산출 (Computation of equivalent material properties of woven fabric composites using homogenization technique)

  • 장지현;윤민우;이진희
    • 대한기계학회논문집A
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    • 제22권3호
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    • pp.588-594
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    • 1998
  • Reliable three-dimensional models of woven fabric composites had scarcely been proposed for their geometric complexity. Simplified models, mostly one- or two-dimensional, currently used are not considered effective enough because of their oversimplifications. In this paper, the equivalent thermal conductivities and elasticity properties of woven fabric composites are computed using homogenization technique. The computational results show that the strength and thermal conductivity linearly increase with fiber volume fraction and that the variations of undulation of fibers has little effect on equivalent material properties. Homogenization technique is proved useful in the study of woven fabric composites and may find a lot more applications in the area.

$ABO_w/AC4CH$복합재료의 제조 및 기계적 특성 (Manufacture and Mechanical Properties of $ABO_w/AC4CH$ Composite Material)

  • 허선철;박원조;허정원
    • 한국자동차공학회논문집
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    • 제9권5호
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    • pp.188-194
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    • 2001
  • Metal matrix composites with whisker reinforcements have significant potential for demanding mechanical applications including defense, aerospace, and automotive industries. Especially, metal matrix composites, which are reinforced with aluminum borate whisker, have been used for the part of piston head in automobile because of good specific strength and wear resistance. Aluminum alloy-based metal matrix composites with whisker reinforcements have been produced using squeeze casting method, which is kind of an infiltration method. In this study, AC4CH-based metal matrix composites with $Al_{18}B$_4$O_{33}$ reinforcement have been produced using squeeze casting method, after T6 heat treatment, we evaluated mechanical properties of matrix and MMC composite were evaluated.

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자기-전기(ME) 복합체를 활용한 초미세 자기장 감지 기술 (Sensing of ultra-low magnetic field by magnetoelectric (ME) composites)

  • 황건태;송현석;장종문;류정호;윤운하
    • 세라미스트
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    • 제23권1호
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    • pp.38-53
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    • 2020
  • Magnetoelectric (ME) composites composed of magnetostrictive and piezoelectric materials derive interfacial coupling of magnetoelectric conversion between magnetic and electric properties, thus enabling to detect ultra-low magnetic field. To improve the performance of ME composite sensors, various research teams have explored adopting highly efficient magnetostrictive and piezoelectric phases, tailoring of device geometry/structure, and developing signal process technique. As a result, latest ME composites have achieved not only outstanding ME conversion coefficient but also sensing of ultra-low magnetic field below 1pT. This article reviews the recent research trend of ME composites for sensing of ultra-low magnetic field.

고온진공가압 티타늄 금속기 복합재료의 미시-기계적 특성에 관한 연구 (A Study on the Micro-mechanical Characteristics of Vacuum Hot Pressed Titanium Metal Matrix Composites)

  • 하태준;김태원
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2003년도 추계학술발표대회 논문집
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    • pp.207-210
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    • 2003
  • Vacuum hot pressing has been used for the development of Ti-MMCs using foil-fiber-foil method, and subsequent micro-mechanical characteristics of the composites are evaluated by means of several experimental processes. As shown by the results, fiber strength degradation occurs during the consolidation, and particularly residual stresses results from the thermal expansion mismatch between fiber and matrix materials during cooling process are incorporated in the changes of mechanical properties of the composites. In industrial applications, the processing conditions avoiding micro-material failures are important together with the properties of finished products, and therefore should be included in the assesment of the material characterization.

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SiC 입자로 분산 강화된 고력 알루미늄 합금 복합재료의 기계적 성질 (Mechanical Properties of High Strength Aluminum Alloy Composites Reinforced by SiC Particulates)

  • 이의길;최운;남승의
    • 한국주조공학회지
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    • 제17권2호
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    • pp.164-169
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    • 1997
  • Mechanical properties of aluminum-matrix composites, fabricated by dispersion of fine SiC particulates of which size was less than 1 ${\mu}m$ into 2024 and 7075 aluminum alloys, have been investigated. Homogeneous mixing between the matrix and SiC particulates could be achieved by jar milling for 8 hours with appropriate processing agent. At temperatures below 473K, high-temperature tensile strength of the composites was higher than that of the 2024 and 7075 aluminum alloys which were used as matrix materials. However, tensile strength of the composites was approximated to that of the matrix materials at 573K. Thus, it could be suggested that effects of particle dispersion on tensile strength of aluminum alloys was diminished at temperatures higher than 573K.

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굴곡진 보강섬유를 가진 두꺼운 복합재료의 인장/압축 비선형 거동 및 강도예측 (Predictions of Nonlinear Behavior and Strength of Thick Composites with Fiber Waviness under Tensile/Compressive Load)

  • 유근수;전흥재
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.819-822
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    • 2001
  • Fiber waviness is one of manufacturing defects encountered frequently in thick composite structures. It affects significantly on the behavior as well as strength of thick composites. Thick composites with fiber waviness have two kinds of nonliearity. One is material nonlinearity, and the other is geometrical nonliearity due to fiber waviness. There are only a few studies that have considered both material and geometrical nonlinearities. In this paper, a FEA model was proposed to predict nonlinear behavior and strength of thick composites with fiber waviness.

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알루미나 단섬유 및 입자강화 알루미늄 청동기지 복합재의 마모특성 (On the Wear Properties of the Alumina Short Fiber and Particle Reinforced Aluminium Bronze Alloy Composite)

  • 이상로;허무영
    • Tribology and Lubricants
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    • 제10권3호
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    • pp.39-46
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    • 1994
  • In order to investigate the effect of the ceramic reinforcements on the wear properties of aluminum bronze composites, Cu-8wt%Al aluminum bronze alloys reinforced with the Saffil alumina short fiber were produced by the powder metallurgical method and tested by a pin-ondisc wear testing machine. The wear surfaces of the pin specimens and discs, wear debris, and the cross sections of the wear specimens were observed by SEM. The wear mechanism according to various wear conditions and the change of microstructure in the composites were also discussed. In the results, the reinforcement of the composites with alumina short fiber was very effective at the higher applied load over 10N. The material transportation to the counter disc was observed in the alloy specimens without reinforcements. However, the composites reinforced with ceramic particles and fibers showed the resistance against the material transportation.

FeCoGe/페놀 복합체의 영률 측정 (Young's Modulus Measurement of FeCoGe/phenol Composites)

  • 박경일;김홍근;신광호;사공건
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 제5회 영호남 학술대회 논문집
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    • pp.107-109
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    • 2003
  • The magnetostriction of FeCoGe/phenol composites is measured under the external magnetic field. A few Measurement are carried out by using the electrical-resistance strain gage, the Wheaton Bridge for eliminating the unnecessary voltage, the lock-in-amplifier for the signal amplification and noise filtering. When the external magnetic field is applied to the longitudinal direction against those samples which is the 10wt.% phenol in composites, the theoretical maximum strain of 120ppm is obtained. According to the larger strain than that of others solid state actuators and piezoelectric actuators. FeCoGe/phenol composites could be useful as an actuator.

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