• 터널과지하공간
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• 제14권5호
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• pp.339-344
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• 2004

침식에 따른 횡방성 암반의 초기응력비 변화를 수치해석적으로 구하여 등방성의 경우 및 이론해와 비교한 결과 횡등방성의 영향은 크지 않아 초기지응력비가 작고 침식심도가 깊을 때만 고려하는 것이 좋을 것으로 판단되었다. 수치해석에 의한 응력과 이론적인 값의 차이는 초기 지응력비가 클수록 또 침식되는 깊이가 증가할수록 증가하였다. 또 침식 후의 초기응력비는 심도가 깊어짐에 따라 초기 응력비로부터 발산하였다. 이를 감안하여 침식에 따른 초기응력비 산정식을 제안하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.139-145
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• 1998

This paper addresses the R-curve properties, wear resistance, and erosion resistance of the two silicon carbide ceramics with different microstructures, i.e. , fine grained SiC and in situ-toughened SiC(IST SIC). Fine grained SiC exhibits a relatively flat R-curve behavior whereas the IST SiC exhibits a increasing R-curve behavior. The increasing R-curve behavior in IST SiC is attributed to relatively weak grain boundaries. The rate of material removal during wear tests and erosion tests was higher for IST SiC than that for fine grained SiC. This is attributed to the weaker grain boundaries in IST SiC than that in fine grained SiC. It is implied that fracture toughness in short crack regime should be taken into consideration in the interpretation of the microscopical material removal process. We show that the higher the strength of grain boundaries is, the higher wear and erosion resistances are.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.199-202
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• 2003

A study for permeability and erosion characteristics of short fiber reinforced soils was performed. As mixing ratio increases from 0 to 1.0% permeability of short fiber reinforced soils increased but, maximum increment ratio($k_{1.0%}/k_{0%}$) was 8.47. As a result of permeability test with 19, 38 and 60mm fiber reinforced soils, there were no difference in fiber length. Void ratio increased with increment of mixing ratio and decrease of compaction energy and as a result of plotting permeability and void ratio, log k increased linearly by void ratio. As a result of erosion test, soil erosion was decreased sharply by increase of fiber mixing ratio up to 1.0%. Despite increase of soil erosion by slope angle, the increment ratio was decreased by mixing ratio.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2008년도 공동추계학술대회
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• pp.251-253
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• 2008

Erosion and landslide cause serious damage to forest areas. As a consequence, partial or complete destruction of vegetation occurs, which leads to many cascading problems. In this study, an attempt has been made to identify the forest areas, which are under different risk categories of erosion and landslide, in part of Eastern Ghats of Tamil Nadu. Relevantthematic maps were generated from satellite data, topographical maps, primary and secondary data and weights to each map were assigned appropriately. Weighted overlay analysis was carried out to identify the erosionprone forest areas. The result of erosion and landslide prone model reveals that 4712 ha(17%) of forest area is under high risk category and 15879 ha(58.65%) isunder medium risk category. The results of spatial modeling would be very much useful to the forest officials and conservationist to plan for effective conservation.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.258-264
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• 1998

Three kinds of reation-bonded SiC that reaction-bonded SiC(RBSC), RBSC reinforced by carbon fiber and RBSC reinforced by activated carbon fiber were prepared for investigating the change of erosion properties. The characteristics of microstructures and the phases have been investigated by using scanning electron microscope and XRD analysis. The hardness test, toughness test and erosion test were camed out. In the cases with no carbon fiber, those kind of specimens had the highest result of hardness test and the lowest result of toughness test. With the increase of carbon fiber content, The hardness and the weight loss were decreased but the toughness was increased in the cases with carbon fiber In the cases with activated carbon fiber those specimens had the highest result of toughness test and the lowest result of hardness test with 30% contents of activated carbon fiber.

• Tribology and Lubricants
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• 제15권1호
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• pp.59-67
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• 1999

Three kinds of reation-bonded SiC that reaction-bonded SiC(RBSC), RBSC reinforced by carbon fiber and RBSC reinforced by activated carbon fiber were prepared for investigating the change of erosion properties. The characteristics of microstructures and the phases have been investigated by using scanning electron microscope and XRD analysis. The hardness test toughness test and erosion test was carried out. In the cases with no carbon fiber, those kind of specimens had the highest value of hardness and the lowest value of toughness. With the increase of carbon fiber content the hardness and the weight loss were decreased, but the toughness was increased in the cases with carbon fiber. In the cases with activated carbon fiber specimens had the highest value of toughness and the lowest value of hardness with 30% contents of activated carbon fiber.

• Journal of Welding and Joining
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• 제20권4호
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• pp.551-556
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• 2002

Solid particle erosion wear characteristics of high Cr white iron hardfacing were investigated using the erosion wear test method according with the ASTM G76-95. Wear experiments, where the blast angle, blast distance and blast pressure were selected as test variables, were planned and analyzed by response surface method (RSM to evaluate the wear loss statistically and quantitatively. The measured wear losses well coincided with the calculated ones by the experimental equation. The wear loss of high Cr cast iron hardfacing was increased with blasting pressure, but affected in a complicated way by the blasting angle and distance. Erosion wear of high Cr cast iron hardfacing could be well predicted by RSM analysis of wear variables.

• 한국주조공학회지
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• 제30권4호
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• pp.142-146
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• 2010

To elucidate the characteristics of cavitation erosion of super duplex stainless steel, a cavitation erosion test, an optical microstructure, a hardness test, and a transmission electron microscope (TEM) analysis were conducted. As aging time at $475^{\circ}C$ increased, the hardness of ferrite phase increased whereas that of austenite phase was nearly constant. The reason why the cavitation erosion resistance increased with an increase of aging time was due to the formation of W-rich phases (${\alpha}$') of a nanometer scale with the high hardness that were precipitated within ${\alpha}$-grains and at ${\alpha}$-grain boundaries during aging, compared with that of the solution annealed alloy.

• International Journal of Precision Engineering and Manufacturing
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• 제9권2호
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• pp.11-17
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• 2008

Critical erosion kinetic energy models for radial/median cracks and lateral cracks in a workpiece are established in this study. We used experimental results to demonstrate that the fracture erosion resistance and erosion machining number could be used to evaluate the brittle fracture resistance and machinability of a workpiece. Erosion kinetic energy models were developed to predict brittle fracture and ductile shear, and a critical erosion kinetic energy model was developed to predict the transition from brittle fracture to ductile shear. These models were verified experimentally.

• 한국표면공학회지
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• 제33권1호
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• pp.10-16
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• 2000

Characteristics of cavitation erosion resistance of Fe-20Cr-1Si-1C-xMn(x=0, 5, 15) alloys were investigated by SEM and XRD analysis. The effects on strain-induced transformations were considerably reduced with increasing the amounts of Mn due to twining that occurred at 5, 15Mn alloys, activating cavitation erosion rates(mg/$\textrm{cm}^2$) which varied as 0.055, 0.114 and 0.160mg/$\textrm{cm}^2$ for 0, 5, 15Mn. From the results, it was found that the addition of Mn element in Fe-base alloy provides more cracking sites at twins rather than absorbing strain energies, so accelerates cavitation erosion rates.