• 한국철도학회논문집
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• 제8권2호
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• pp.188-194
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• 2005

Aging characteristics of glass fabric/phenolic composites for tilting train subjected to combined environmental aging factors were investigated. A 2.5KW accelerated aging tester with a xenon-arc lamp was used to provide environmental aging factors such as temperature, moisture, and ultraviolet. A series of aging tests were conducted up to 3000 hours and several types of specimens were prepared along the warp direction and the fill direction. Mechanical degradations for tensile, flexural, and shear properties were evaluated as a function of exposure times through a material testing system. Thermal analysis properties such as storage shear modulus, loss shear modulus, and tan 3 were measured through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using a scanning electron microscope. According to the experimental results, mechanical properties and thermal analysis properties of glass fabric/phenolic composites were found to be slightly degraded as a function of exposure times due to combined environmental effects.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.391-396
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• 2005

Salt water spray test and salt water immersion test were experimentally conducted in order to investigate the durability of fiber reinforced composites under salt water environment. The specimens were made of glass fabric reinforcement and phenolic resin. Mechanical test was performed to obtain mechanical properties such as tensile properties, flexural properties, and shear properties by varying with exposure times. Also dynamic mechanical test and FTIR were conducted to investigate a change in chemical structure as well as thermal analysis properties such as storage shear modulus, loss shear moduls, and tan ${\delta}$. According to the results, salt water environment has effected on mechanical properties and thermal analysis properties and especially the durability of glass fabric/phenolic composites were severely affected on salt water immersion environment rather than salt water spray environment.

• Composites Research
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• 제18권4호
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• pp.27-34
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• 2005

염수시험기를 통해 6개월 동안 염수분무시험과 염수침수시험을 수행함으로써 염수환경에 노출된 유리섬유직물페놀 복합재의 내구성을 실험적으로 조사하였다. 이때 염수환경에 노출된 시간에 따른 인장특성, 굽힘특성, 전단특성 등의 기계적 특성을 평가하고 동역학 측정장치를 적용하여 저장전단탄성계수. 손실전단탄성계수, tan $\delta$ 등의 열분석 특성을 측정하였다. 또한 적외선 분광분석기를 적용하여 염수환경에의 노출시간에 따른 화학구조의 변화를 분석하였다. 연구결과에 따르면 기계적 특성과 열분성 특성은 노출시간에 민감하게 변하며 노출시간이 길어짐에 따라 점차 감소되는 양상을 나타낸다. 그러나 강성의 경우에는 염수환경에 노출되면 복합재의 가소화로 인해 노출의 초기에는 감소하기 시작하고 노출시간이 길어짐에 따라 복합재의 팽창, 수지의 소성화, 가교 결합의 증가 등으로 인해 다소 증가하는 양상을 나타내지만 노출시간이 더욱 더 길어지면 점차 감소할 것으로 추측된다. 또한 FT-IR 선도에서의 피크 형상과 위치는 노출시간에 큰 영향을 받지 않으며 피크 세기는 노출시간에 따라 달라진다. 마지막으로 염수침수환경은 염수분무환경에 비해 유리섬유직물/복합재의 내구성에 더욱 심각한 영향을 미침을 알 수 있었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.352-357
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• 2004

In this study. the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated through a 2.5KW accelerated environmental aging tester. Environmental factors such as temperature. moisture, and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile, bending, and shear specimens those are warp direction and fill direction were used to investigate the effects of environmental factors on mechanical properties of the composites. The glass fabric $\sharp$650/AP300 was used for the fabrication of specimens. Mechanical degradations for tensile, bending and shear properties were evaluated through a UTM. Also. storage shear modulus. loss shear modulus, and tan $\delta$ were measured as a function of exposure times through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using II scanning electron microscope.

• International Journal of Railway
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• 제1권3호
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• pp.113-116
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• 2008

The long-tenn exposure of polymeric composite materials to extreme-use environments, such as pressure, temperature, moisture, and load cycles, results in changes in the original properties of the material. In this study, the effect of combined environmental factors such as ultraviolet ray, high temperature and high moisture on mechanical and thermal analysis properties of glass fabric and phenolic composites are evaluated through a 2.5 KW accelerated environmental aging tester. The environmental factors such as temperature, moisture and ultraviolet ray applied of specimens. A xenon-arc lamp is utilized for ultraviolet light and exposure time of up to 3000 hours are applied. Several types of specimens - tensile, bending, and shear specimens that are warp direction and fill direction are used to investigate the effects of environmental factors on mechanical properties of the composites. Mechanical degradations for tensile, bending and shear properties are evaluated through a Universal Testing Machine (UTM). Also, storage shear modulus, loss shear modulus and tan a are measured as a function of exposure time through a Dynamic Mechanical Analyzer (DMA). From the experimental results, changes in material properties of glass fabric and phenolic composites are shown to be slightly degraded due to combined environmental effects.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.86-91
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• 2002

Glass/phenolic composite laminates have been used in the field of non-flammable light rail transit and their applications have expanded more widely. Low velocity impact tests have been used to evalute the effect of temperature and acceleration aging on low velocity impact response of phenolic matrix composites reinforced with woven E-glass fabric. The damage of matrix cracking and delamination are suddenly reduced the compressive strength after impact. The damage area increases with increasing temperature and impact energy. UT C-scan is used to determine damage areas by impact loading. Therefore, all this observations indicate reduced impact damage resistance and damage tolerance of the laminates at elevated temperature.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.51-54
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• 2004

Testing methods for mechanical properties of the advanced composites were introduced. The mechanical properties, such as tensile properties, compressive properties, in-plane shear properties, flexural properties, and interlaminar shear properties, were evaluated along the warp and the fill directions. The CF3327 of the carbon fabric, the HG1581 of the glass fabric, and the HK285 of the aramid fabric were considered as reinforcements. Epoxy and phenolic resin were used as resin. The experimental results obtained in this study would be applicable in the design and structural analysis for the manufacture of the carbody of the tilting train.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.93-96
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• 2002

Instrumented impact tests and compression-after-impact(CAI) tests have been used to evaluate the effect of temperature on the low-velocity impact characteristics of phenolic matrix composites reinforced with various woven glass fabric. Impact characteristics and damage area in laminates are evaluated by C-scan. It is shown that the extent of damage and residual compressive strength of the laminates vary with energy level and impact test temperature. The damage area increases with increasing impact energy and temperature. All these observations indicate reduced impact damage resistance and damage tolerance of the laminates at elevated temperature.