• 접착 및 계면
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• 제3권2호
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• pp.17-29
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• 2002

Micromechanical 시험법과 표면 젖음성 측정을 이용한 implant용 생분해성 복합재료의 계면물성과 미세파괴 분해 메카니즘을 연구하였다. 분해시간이 경과함에 따라서 poly(ester-amide) (PEA)와 생활성 유리섬유의 인장강도와 탄성률 그리고 신율은 점차적으로 감소하는 경향을 보인 반면, chitosan 섬유는 거의 변화가 없었다. 생활성 유리섬유와 poly-L-lactide(PLLA) 사이의 계면전단강도는 PEA나 chitosan 섬유 시스템의 경우보다 더 큰 값을 보였으나, 계면전단강도 감소 속도는 가장 빨랐고 chitosan 섬유의 경우가 가장 느린 결과를 보였다. 접착일 ($W_a$)은 생활성 유리섬유와 PLLA 사이에서 가장 높은 값을 나타냈으며, 이러한 표면 젖음성 결과는 계면전단강도 결과와 잘 일치하였다. 계면물성과 미세파괴 분해 메카니즘은 생분해성 복합재료의 성능을 조절할 수 있는 가장 중요한 요인들이다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.373-373
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• 2006

Rigid polyurethane foams(PUFs) are widely used in most areas of insulations such as storage tank and pipe line for transporting liquefied gas. Glass fiber and nanoclay are used for improvement in mechanical property and thermal insulation of rigid PUF at very low temperature(<$-150^{\circ}C$). These rigid PUFs have been characterized in terms of thermal, mechanical, dynamic mechanical properties and cell morphology. It was found that mechanical properties, thermal conductivity and dimensional stability of rigid PU foams were improved by glass fiber and nanoclay.

• 한국농공학회논문집
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• 제46권6호
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• pp.37-45
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• 2004

In this study, twelve different glass fiber reinforced polymer concrete composite panel specimens with various rib heights and tensile side and reinforced side thickness were produced, and the flexural tests were conducted to figure out the effect of The height and thickness influencing on the flexural properties of composite panel. Test results of the study are presented. Especially, a prediction equation of the ultimate moment based on the strength design method agrees well with the test results, and it is thought to be useful for the corresponding design of cross-section according to various spans as the glass fiber reinforced polymer concrete composite panel is applied for a permanent mold.

• Computers and Concrete
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• 제7권2호
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• pp.169-190
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• 2010

The focus of this research effort was characterization of the flexural and tensile properties of a specific ultra-high-strength, fiber-reinforced concrete material. The material exhibited a mean unconfined compressive strength of approximately 140 MPa and was reinforced with short, randomly distributed alkali resistant glass fibers. As a part of the study, coupled experimental, analytical and numerical investigations were performed. Flexural and direct tension tests were first conducted to experimentally characterize material behavior. Following experimentation, a micromechanically-based analytical model was utilized to calculate the material's tensile failure response, which was compared to the experimental results. Lastly, to investigate the relationship between the tensile failure and flexural response, a numerical analysis of the flexural experiments was performed utilizing the experimentally developed tensile failure function. Results of the experimental, analytical and numerical investigations are presented herein.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 봄 학술발표회 논문집
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• pp.5-10
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• 1990

There are two main methods in reinforcing cements with glass fibers : spray-suction and premixing method. But GRC have been mostly studied by spray technique. In order to develop GRC made by premixing method, in this paper, the influence of glass fiber length, volume content and curing conditions upon the compressive, direct tensile and bending strengths of composites fabricated by a premixing method, were investigated. According to the test results, although it was difficult to obtain perfectly uniform distribution of fibers in GRC Pannel, it was found that tensile strength of cements with glass fiber was improved 2~5 times and flexural strength 4 times compared to conventional cement mortar upto fiber length 35 mm, volume content 4%.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권6호
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• pp.321-327
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• 2000

FRP has been used very much as high strength and electrical insulation materials. The fiber contributes the high strength and modulus to the composite. The main roles of the matrix in composite materials like FRP are to transmit and distribute stresses among the individual fibers. The fiber orientation in FRP has a great effect on the strength of FRP because the strength of FRP mainly depends on the strength of fiber. In this study, compressive and bending stresses of FRP rods were simulated and measured according to the winding orientation of glass fiber. Inner part of FRP was made unidirectionally by pultrusion method and outer part of FRP was made by filament winding method to give fiber orientation to the FRP. The shear stresses had great effect on the strength of FRP although the stress of parallel direction of FRP was much higher. The tendency of compressive and bending strengths with glass fiber orientation was different each other.

• 소성∙가공
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• 제32권3호
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• pp.129-135
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• 2023

The use of engineering plastic products in internal combustion engine and electric cars to improve stiffness and reduce weight is increasing significantly. Among various lightweight materials, engineering plastics have significant advantages such as cost reduction, improved productivity, and weight reduction. In particular, engineering plastics containing glass fibers are used to enhance stiffness. However, the stiffness of glass fibers can increase or decrease depending on their orientation. Before developing plastic products, optimal designs are determined through injection molding and structural analysis to enhance product reliability. However, reliable analysis of products with variable stiffnesses caused by anisotropy cannot be achieved via the conventional isotropic structural analysis, which does not consider anisotropy. Therefore, based on the previously reported study "the Effect of Impacted Fracture in Glass Fiber Orientation with Injection Molding & Structural Coupled Analysis," this study aims to investigate the structural analysis and degradation mechanisms of various polymers. In particular, this study elucidates the actual mechanism of plastic fracture by analyzing various fracture conditions and their corresponding simulations. Furthermore, the objective of this study is to apply the injection molding and structural coupled analysis mechanism to develop engineering plastic products containing glass fibers. In addition, the study aims to apply and improve the plastic fracture mechanism in actual products by exploring anisotropy and stiffness reduction owing to the unfilled polymer weld line.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 추계학술대회논문집
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• pp.181-187
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• 1995

The effet of glass fiber and graphite on the wear properies in tin-bronze alloy matrix composites was studied by a pin-on-disk type wear testing machine. The results obtained from the wear test were analized by SEM observations of worn surfaces of pins and disks and EPMA composition measurments. The amount of wear was devreased as increasing the content of glass fiber in matrix, since the alloy matrix was reinforced by glass fibers. The wear mechanism of the matrix specimen without glass fibers was proved as the contact area delamination. Oxide layer formed on sliding surface led to the increasing wear resistance. Specimens containing graphite particles showed an lubrication effect to counter disks.

• 한국해양공학회지
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• 제30권6호
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• pp.520-525
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• 2016

In this study, a mixture of polypropylene fibers and glass fibers were used to weave polypropylene/glass fiber-reinforced composite panels with characteristics such as highly elongated short fibers, high ductility, anti-fouling, and hydrophobicity as a result of a directional property. Mechanical and environmental tests were carried out with specimens fabricated with this composite panel, and its applicability to shipbuilding and ocean leisure industries was evaluated through a comparison with existing glass fiber-reinforced composite materials. The results of this experiment verified the excellence of the polypropylene/glass-mixed woven fiber-reinforced composite material compared to the existing glass fiber-reinforced composite material. However, the forming process needs to be changed to improve the weak interfacial bonding, and the properties of the composite material itself could be improved through mixed weaving with other fibers after development. Maximizing of the advantages of the polypropylene fibers and overcoming their shortcomings will improve their applicability to the shipbuilding, ocean leisure, and other industries, and increase the value of polypropylene fibers in the composite material market.

• 대한치과보철학회지
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• 제42권3호
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• pp.280-293
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• 2004

Statement of problem. Glass fiber post is one of recent developments to accommodate esthetic restoration for endodontically treated teeth. This has many advantages over conventional post system in physical properties, esthetic factor, risk of root and restoration fracture, adhesion to core, radiopacity, removal and retrievabilty, biocompatibility and chemical stability. Purpose. This in vitro study was to evaluate the most suitable type of resin core for the glass fiber post through surveying the fracture modes and the maximum load that fractures the tooth. Material and methods. 50 sound maxillary premolars restored with glass fiber posts($ParaPost^{(R)}$ Fiber White) and different types of resin cores(ParaCore, $Z100^{TM}$, $Rebilda^{(R)}$ and $Admira^{(R)}$) were prepared and loaded to faiure in a universal test machine. The maximum fracture load and fracture mode were investigated in the specimens that were restored with resin and those of metal cast and core. With the data, Wilcoxon rank sum test was used to validate the significance between the test groups, and Tukey' s studentized range test was used to check if there is any significant statistical difference between each test group. Every analysis was approved with 95% reliance. Results. On measuring the maximum fracture load of teeth specimens, there was a significant difference between the maximum fracture loads of the tooth specimens. ParaCore showed the highest mean maximum fracture load followed by $Z100^{TM}$. And, the distribution of fracture mode of tooth specimens showed generally Type D, the three parted fracture of the core around the post was mostly seen(62.5%), and specifically, ParaCore showed 90% and $Z100^{TM}$ showed 100% Type D fracture. Conclusion. Referring to the values of maximum fracture load and mean compressive fracture load, ParaCore and $Z100^{TM}$ had high values and are recommended as tooth colored resin core material for glass fiber post. CLINICAL IMPLICATIONS. This study was carried out intending to be of aid in selecting the appropriate resin core for the glass fiber post. The dual cure type composite resin ParaCore and light cure type composite resin $Z100^{TM}$ have good properties and are recommended as tooth colored resin core material for glass fiber post.