• Composites Research
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• v.28 no.1
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• pp.22-27
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• 2015

Although it is important to have high strength of each of fiber and matrix, interface between fiber and matrix is most important. If NaCl water penetrates the interface, that area will be weak. So experiment about increasing interfacial strength is in process. In this study, the change of properties by mechanical, interfacial and micromechanical tests was observed after NaCl and aging treatment. The changes in mechanical properties of glass fiber were investigated using single-fiber tensile test. Interfacial properties between glass fiber and epoxy resin were evaluated using nondestructive acoustic emission (AE) and micromechanical test applied to fatigue test. Through change of fatigue properties, relative interfacial properties were evaluate. In conclusion, glass fiber diameter decreased and the reduction of mechanical and interfacial was observed with NaCl solution and aging treatment.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.107-110
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• 2003

본 연구에서는 3차원 브레이딩 기계를 이용하여 제작된 6 layer의 3차원 원형 형태로 브레이드된 유리 섬유 강화 복합재료의 프리프레그를 이용하여 에폭시 수지를 모체로 하는 RTM(Resin Transfer Molding) 공정을 통해 직교 이방성 복합재료를 제작하였다. 또한 탄성한계 내에서의 구성방정식을 얻기 위해 unit cell 모델링을 통해 복합재료의 기하를 모사하고 method of cells 이론과 homogenization technique를 이용하여 복합재료의 구성방정식을 나타내는 수치해석 코드를 개발하였다. (중략)

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.429-438
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• 2003

The effects of fiber orientation on acoustic emission(AE) characteristics have been studied for the unidirectional and satin-weave, continuous glass-fiber reinforced plastic(UD-GFRP and SW-GFRP) tensile specimens. Reflection and transmission optical microscopy was used for investigation of the damage zone of specimens. AE signals were classified as different types by using short time fourier transform(STFT) : AE signals with high intensity and high frequency band were due to fiber fracture, while weak AE signals with low frequency band were due to matrix and interfacial cracking. The feature in the rate of hit-events having high amplitudes showed a process of fiber breakages, which expressed the characteristic fracture processes of individual fiber-reinforced plastics with different fiber orientations and with different notching directions. As a consequence, the fracture behavior of the continuous GFRP could be monitored as nondestructive evaluation(NDE) through the AE technique.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.4
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• pp.247-254
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• 2012

Vitrification technology has been widely applied as one of effective processing methods for wastes generated in nuclear power plants. The advantage of vitrifying for low- and intermediate-level radioactive wastes has a large volume reduction and good durability for the final products. Recently, a filter using on HVAC(Heating Ventilating & Air Conditioning System) is composed with media (glass fiber) and separator (aluminum film) has been studied the proper treatment technology for meeting the waste disposal requirement. Present paper is a feasibility study for the filter vitrification that developing of the glass compositions for filter melting and melting test for physicochemical characteristic evaluation. The aluminum metal of film type is preparing with 0.5 cm size for proper mixing with glass frit, glass fiber is also preparing with 1 cm size within crucible. The glass compositions should be developed considering molten glass are related with wastes reduction. Glass compositions obtained from developing on glass formulation are mainly composed of $SiO_2$ and $B_2O_3$ for aluminum metal. A variety of factors obtained from the glass formulation and melting test are reviewed, which is feeding rate and glass characteristics of final products such as durability for implementing the wastes disposal requirement.

• Composites Research
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• v.13 no.4
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• pp.75-82
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• 2000

A small diameter steel-ball impact experiment was performed to study the impact resistance of the surface of glass plates bonded with glass fabric/epoxy lamina. Five kinds of materials were used in this study: soda-lime glass plates, glass/epoxy lamina(one layer)-bonded and unbonded glass plates, glass/epoxy lamina(three layers)-bonded and unbonded glass plates. The range of impact velocity was 40 120m/s. The maximum stress and absorbed fracture energy were measured on the back surface of glass plates. With increasing impact velocity, various types of surface cracks such as ring, cone, radial and lateral cracks took place in the interior near the impacted site of glass plates. The cracks drastically decreased with glass/epoxy lamina coating. The surface fracture behavior could be evaluated using the maximum stress and the absorbed fracture energy.

• Polymer(Korea)
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• v.24 no.4
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• pp.459-468
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• 2000

To improve the mechanical properties of fiber-reinforced polymer matrix composites, laminated composites plates were fabricated using different matrix resins and glass or aramid fibers. The effect of matrix resin system were evaluated by tensile, flexural strength measurements. In the case of surface treated aramid fiber and unsaturated polyester resin composite, maximum flexural properties were observed in the composite prepared from the glass fiber treated with 0.5 wt% silane coupling agents. Vinylester resin composites show the highest tensile properties and isophthalic polyester composites have the highest flexural properties among the unsaturated polyester resin composites studied. The relationship between overlap laminated composites plates and mechanical properties of polymer composites is also investigated in order to improve mechanical properties of glass fiber and unsaturated polyester resin composites.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.163-169
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• 2017

Although the strength of polyethylene terephthalate (PET) fibers which are generally used to make plastic bottles is low, the deformability of PET fibers is substantially high. Due to these material characteristics, a PET fiber can be used as a reliable strengthening material to resist a large deformation caused by earthquake and research pertinent to application of PET fibers is actively conducted in Japan. Therefore, in this study, experiments have been carried out to investigate the lateral confinement effect of PET fibers and to assess the applicability of PET fibers to construction fields by comparing the strengthening effect of PET fibers to that of carbon and glass fiber sheets. For this purpose, concrete cylinder specimens with parameters of different concrete strength and strengthening layers of carbon fiber sheets, glass fiber sheets, and PET fibers were respectively tested using two sets of cylinders for each parameter. As a result, specimens strengthened with carbon fiber sheets and glass fiber sheets failed due to sudden decrease of strength as with existing studies. However, specimens with PET fibers reached their maximum strength and then failed after gradual decrease strength without failure of PET fibers. In addition, although the strength of specimens with PET fibers did not significantly increase in comparison with that of specimens with carbon fiber sheets and glass fiber sheets, specimens with PET fibers indicated considerable deformability. Thus, a PET fiber can be considered as an effective strengthening material.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.189-190
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• 2003

섬유강화 복합재료의 사용이 점점 증가함에 따라 구조용 및 내장재 등으로 사용된 수명이 다한 섬유강화 복합재료의 사용후 폐기가 문제가 되고 있다. 특히, 자동차 부품, 건축자재 및 전기절연재 등으로 가장 많이 사용되는 유리섬유 복합재료의 폐기물이 급격히 증가하여 환경 오염문제가 심각해지고 있어서, 환경 친화적인 새로운 복합재료에 대한 필요성이 제기되어 왔다. 따라서 본 연구에서는 천연섬유를 이용한 천연섬유/생분해성 수지계 복합소재를 대상으로 환경적합성이 우수하고 자연환경에서 완전한 생분해성을 가지며, 유리 섬유복합재료를 대체할 물성이 우수한 새로운 Biocomposite를 개발하고자 하였다. (중략)

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.4
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• pp.159-165
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• 2021

The fiber composites have been investigated as lightweight structure material platforms for aerospace applications because their strength can be enhanced by adding reinforcement without a significant increase in weight. In this study, the fabrication and characterization of carbon nanotube (CNT) reinforced glass fiber composites are demonstrated to enhance the tensile strength of longitudinal direction along the glass fibers. Due to the reinforcement of CNT in epoxy layers, the yield strength of fiber/epoxy composites is enhanced by about 10 %. Furthermore, using scanning electron microscopy, analysis of fracture surfaces shows that mixed CNT in epoxy layers acts as necking agents between fractured surfaces of fiber/epoxy; thereby, initiation and evolution of crack across fiber composite can be suppressed by CNT necking between fractured surfaces.

• Proceedings of the Korean Fiber Society Conference
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• 1992.06b
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• pp.34-34
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• 1992