• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• Composites Research
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• v.23 no.1
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• pp.17-22
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• 2010

The compressive and dynamic properties of magnetorheological elastomers were investigated as functions of magnetizable particle volume fraction, alignment of the embedded particle and magnetic force. The specimens consisted of pure and filled silicons with randomly dispersed, longitudinal and transverse aligned magnetizable particle chains. To align the embedded particles in the elastomer, the cross-linking of the elastomer composites took place in a magnetic field. The compression and dynamic tests in the absence and the presence of different magnetic forces were carried out. The modulus and loss factor of the elastomer composites increase with increasing volume fraction at the same magnetic force. The case of longitudinal alignment shows a high modulus and loss factor when compared to the case of transverse alignment or random dispersion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.556-560
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• 1996

In order to examine thd accuracy of intersection counting method, the fiber orientation distribution of simulation figure platted by PC is measured using image processing. The fiber orientation distribution obtained by an image processing method is compared with those by the intersection counting method. The result shows that the errors of the intersection counting method are large because its measurement is made by the cross point of the scanning line and the fiber.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.104-113
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• 1993

Characteristics of fiber-reinforced thermoplastic sheet depend on the quantity and shape of fibers. During a molding process of composites, the fiber-maxtrix separation and fober orientation are caused by the flow during the molding process. As a result, the product tends to be nonhomogeneous and anisotropic. Hence, it is very important to clarify the relations between separation-orientation and molding conditions. The correlation between the separation and the orientation have to be clarified for designing the fiber 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 scammer. Correlation between the degree of nonhomogeneity and the orientation function is discussed.

• Proceedings of the Korean Fiber Society Conference
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• 2000.04a
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• pp.169-172
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• 2000