• Title, Summary, Keyword: 섬유배향함수

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A Study on Fiber Orientation by Image Processing during Press Molding of Long Fiber-Reinforced Thermoplastic Sheet (장섬유강화 고분자복합판의 프레스성형에 있어서 화상처리에 의한 섬유의 배향에 관한 연구)

  • 조선형;이동기;김이곤
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.3
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    • pp.834-842
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    • 1991
  • 본 연구에서는 화상처리에 이용되는 차분오퍼레이터중 Sobel오퍼레이터를 이 용하여 성형품의 윤랑선유추출을 하여, 섬유배향각분포를 구하고, Prewitt 오퍼레이터 의 경우와 비교한다. 또 프레스성형시 발생하는 장섬유의 2차원배향상태를 파악하기 위하여 섬유배향함수에 미치는 명종 성형조건의 영향에 대한 결과를 보고한다.

Accuracy Comparison between Intensity Method and Count Method in Measurement of Planar Orientation of Fibers Using Image Processing (화상 처리를 이용한 섬유 배향각 분포 측정에서 농도법과 카운트법의 정확도 비교)

  • Lee, S.D.;Kim, H.;Lee, D.G.;Han, G.Y.;Kim, E.G.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.18 no.5
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    • pp.357-364
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    • 1998
  • To investigate accuracies between intensity method and count method for measurement of the fiber orientation distribution, fiber orientation function is derived by drawing simulation figure for the fiber orientation as varying fiber aspect ratio, fiber area ratio, and fiber orientation state, respectively. The values of fiber orientation function measured by intensity method and count method are compared with the calculated ones from simulation figures. The results show that measurement accuracy of fiber orientation angle distribution obtained by count method is by 4% higher than that by intensity method.

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A Rheological Analysis on the Semiconcentrated Fiber Suspensions Including Fiber-fiber Interactions (섬유간 상호작용을 고려한 진한 섬유현탁액에 대한 유변학적 해석)

  • 이성재
    • The Korean Journal of Rheology
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    • v.8 no.1
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    • pp.49-57
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    • 1996
  • 단섬유 강화복합재료의 가공공정에 있어서 유동 중에 일어나는 섬유 배향상태를 정 확히 예측하고 제어하는 일은 대단히 중요하다. 본 연구에서는 섬유현탁액의 거동을 살펴보 기 위하여 뉴톤유체를 매질로하는 섬유현탁액을 대상으로 하여 유변학적 해석을 하였다. 이 를 위해 섬유간 상호계수는 섬유배향상태의 함수의 섬유간 평균거리를 이용하여 계산하였는 데, 섬유간 평균거리는 변형된 Doi-Edwards의 방법을 이용하였다. 축대칭 압출팽창 문제를 예로 수치모사를 하여 본 저자들이 앞서 행한 결과와 비교하였다. 유동장을 축대칭 이차원 으로 하고 섬유배향을 삼차원 모두 고려하여 구한 수치모사의 결과는 실험과 잘 일치하였 다. 진한 섬유현탁액의 경우 섬유간 상호계수는 중요한 인자로서 이것을 섬유 배향상태에 의존하는데 이섬유간 상호계수를 섬유간 거리와 섬유배향상태의 함수로 나타내는 방법을 사 용하여 보다 실제적인 해석을 할수 있었다.

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Effect of Fiber Orientation and Fiber Contents on the Tensile Strength in Fiber-reinforced Thermoplastic Composites (섬유배향과 섬유함유량이 섬유강화 열가소성수지 복합재료의 인장강도에 미치는 영향)

  • Kim, Jin-Woo;Lee, Dong-Gi
    • Composites Research
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    • v.20 no.5
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    • pp.13-19
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    • 2007
  • Fiber-reinforced thermoplastic composites not only approach almost near to the strength of thermosetting composite but also has excellent productivity, recycling property, and impact resistance, which are pointed as weaknesses of thermosetting composites. The study for strength calculation of one direction fiber-reinforced thermoplastic composites and the study measuring precisely fiber orientation distribution were presented. Need the systematic study for the data base that can predict mechanical properties of composite material and fiber orientation distribution by the fiber content ratio was not constructed. Therefore, this study was investigated what affect the fiber content ratio and fiber orientation distribution have on the strength of composites. Fiber-reinforced thermoplastic composites by changing fiber orientation distribution and the fiber content ratio were made. Tensile strength ratio of $0^{\circ}$ direction of fiber-reinforced composites increased being proportional the fiber content and fiber orientation function as change from isotropy(J=0) to anisotropy(J=1). But, tensile strength ratio of $90^{\circ}$ direction by separation of fiber filament decreased when tensile load is imposed fur width direction of reinforcement fiber length direction.

Fiber Bridging Model Considering Probability Density Function of Fiber Inclined Angle in Engineered Cementitious Composites (보강 섬유의 배향각에 대한 확률밀도함수를 고려한 ECC내의 섬유 가교 모델)

  • Kang, Cheol-Ho;Lee, Bang-Yeun;Park, Seung-Bum;Kim, Yun-Yong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.6
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    • pp.587-596
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    • 2009
  • The fiber bridging model is the crucial factor to predict or analyze the tensile behavior of fiber reinforced cementitious composites. This paper presents the fiber bridging constitutive law considering the distribution of fiber inclined angle and the number of fibers in engineered cementitious composites. The distribution of fiber inclined angle and the number of fibers are measured and analyzed by the image processing technique. The fiber distribution are considerably different from those obtained by assuming two- or three-dimensional random distributions for the fiber inclined angle. The simulation of the uniaxial tension behavior was performed considering the distribution of fiber inclined angle and number of fibers measured by the sectional image analysis. The simulation results exhibit multiple cracking and strain hardening behavior that correspond well with test results.

A Study on Correlation Between Separation and Orientation of Fibres During Compression Molding of Long Fibre-Reinforced Polymeric Composites (장섬유강화 고분자복합판의 압축성형에 있어서 섬유의 분리와 배향의 상관관계에 관한 연구)

  • 이동기;유정훈;김이곤
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.1
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    • pp.62-68
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    • 1993
  • During compression molding of fibre-reinforced thermoplastics, the two main problems such as the fibre-matrix separation and the fibre orientation are produced by the flow state. As the molded product tends to be nonhomogeneous and anisotropic due to the separation and the orientation, it is necessary to clarify these in relation to the molding process variables and the fibre structure (fibre entanglement). If the entanglement of fibre structure is strong, the separation increases and the orientation is not easily aligned. Namely, these are inseparably related to each other. The correlation between the separation and the orientation have to be clarified for designing the fibre structure. In this paper, the degree of nonhomogeneity which is a measure of the separation is obtained using one-dimensional rectangular shaped part compression molding. And the orientation function is defined and measured by the image processing using soft X-rayed photograph and image scanner. Correlation between the degree of nonhomogeneity and the orientation function is discussed.

열가소성 고분자 복합재료의 성형에 있어서 섬유의 분리 및 배향

  • 김이곤
    • Journal of the KSME
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    • v.32 no.1
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    • pp.39-45
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    • 1992
  • 고분자 복합재료를 성형할 때 발생하는 두가지 문제점은 섬괘의 분리와 배향이다. 이 분리 및 배향은 성형조건, 섬괘의 구조 등에 의해서 영향을 받고 이 분리 . 배향을 성형 조건, 재료 등과 관련시켜서 명확히 하는 것은 복합재료의 설계, 복합재료의 부품설계, 신복합재료의 개발에 매우 중요하다. 또 이 분리와 배향은 별개의 것이 아니라 불가분의 관계가 있으며, 분리를 표현하는 불균질도라 배향의 정도를 나타내는 배향함수의 상관관계로부터 복합재료의 설계에 지침을 줄 수 있다고 생각된다.

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The comparison of the tensile strength of fiber-reinforced composites according to the change of fiber orientat and fiber orientation angle in one direction (섬유배향과 일방향 섬유배향각 변화에 다른 복합재료의 인장강도 비교)

  • Kim Jin-Woo;Lee Jung-Ju;Lee Dong-Gi
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.284-287
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    • 2004
  • After we experiment one direction fiber reinforced composites$(\theta\;=\;0^{\circ},\;J=1)$ to the X direction$(\theta\;=\;0^{\circ},\;J=1)$, we can say that fiber orientation efficiency and fiber orientation angle efficiency become lower. It is because the more the fabric is orientated in a equal direction with one direction fiber floor the more the load given from the exterior becomes shear rather than tension, even though one direction fiber floor gets the most of the exterior power. when fiber content ration is $10wt\%$, the fiber reinforcement efficiency of J=0.3 is similar with the fiber reinforcement efficiency of $\theta=30^{\circ}$ We also found that the fiber reinforcement efficiency of J=0.2 is similar with the fiber reinforcement efficiency of $\theta=20^{\circ}$ in case of $20wt\%$.

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The Mechanical Property by Fiber Orientation Distributions in Fiber-Reinforced Polymeric Composites (섬유강화 고분자 복합재료에서 섬유배향상태에 따른 기계적 성질)

  • Lee, Dong-Gi;Sim, Jae-Ki;Han, Gil-Young;Kim, Hyuk;Kim, Jin-Woo;Lee, Jung-Ju
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.202-205
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    • 2003
  • Investigated whether fiber orientation situation of fiber reinforcement macromolecule composition board and the fiber inclusion rate are perpendicular and horizontal direction tensile strength and some correlation. Fiber orientation situation of tensile strength of 0 direction of composition board increased changelessly by aeolotropy in isotropy. Tensile strength of 90 direction that is isotropy and tensile strength of 0 direction that is aeolotropy agreed almost. Get into aeolotropy, the reinforcement rate of fiber decreased. When load interacts for width direction of reinforcement.

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