• 동력기계공학회지
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• 제7권2호
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• pp.44-50
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• 2003

The power steering hose is a kind of high-pressure hose with reinforced braids in rubber material. It is usually manufactured through the swaging process. In this paper, the deformation characteristics of a power steering hose during the swaging process were analyzed using the nonlinear finite element method. The material properties were obtained on experiments, and the contact conditions were used in consideration of real manufacturing process. Investigations were focused on the stress and strain values of the hose and meta] components at the maximum jaw stroke and at the completion of the process. Especially, the results of inner rubber component were interpreted in detail, because of its important role in the hose efficiency.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.194-200
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• 1999

An elastomeric bushing is a device used in automotive suspension systems to cushion the force transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid metal shaft at its inner surface and a metal sleeve at its outer surface. For axial motion case, the relation between the force applied to the shaft and their relative displacement was considered. In this paper, the relation between the moment applied to the shaft and their relative deformation(angle of rotation) is considered for the torsional motion case. Numerical solutions of the boundary value problem represent the exact bushing response for use in the method for determining the moment relaxation function of the bushing. Solutions also allow for comparison between the exact moment-deformation behavior and that predicted the proposed model. It is shown that the predictions of the proposed moment-deformation relation are in very good agreement with the exact results.

• 연구논문집
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• 통권23호
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• pp.15-27
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• 1993

The single crystal specimens were solidified by modified Bridgeman method. The surface recrystallized single crystal specimens were prepared by shot peening followed by heat treatment. The surface recrystallization begins at the dendrite cores on the surface. The recrystallized grains grew into the inner side of the specimen. The growth of recrystallized grains was inhibited by the pores and eutectic phases. The primary $\gamma'$ phases were dissolved at the recrystallized grain boundaries during the grain growth. The grain growth of recrystallized grains was similar to the cellular type transformation. No orientation relationships were found bewteen the recrystallized grains and the parent phase.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권3호
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• pp.157-161
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• 2004

We present a simple analytical expression of plasma density by making use of the electron density equation to study the dynamic behavior of the corona discharge plasma. It assumes that a specified voltage profile is fed through the inner conductor of the reactor chamber consisting of two coaxial conducting cylinders. The analytical description is based on the electron continuity equation with ionization and attachment by electrons. It is found that the electron density profile calculated between two coaxial cylindrical electrodes depends very sensitively on the Profile of applied voltage. The analytical expression of plasma density and its generation will provide important scaling laws in the corona discharge plasma.

• 한국표면공학회지
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• 제36권2호
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• pp.128-134
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• 2003

Alloys of Ti-43%Al-2%W-0.1%Si were oxidized isothermally and cyclically between $900^{\circ}C$ and$ 1050^{\circ}C$, and their oxidation characteristics were studied. During isothermal tests, the alloys oxidized slowly up to 100$0^{\circ}C$, but fast at $1050^{\circ}C$. Though the scale adherence was not good above $900^{\circ}C$, the alloys displayed better oxidation behavior than unalloyed TiAl alloys. The oxide scales consisted primarily of an outer $TiO_2$ layer, intermediate $Al_2$$O_3$-rich layer, and an inner mixed layer of (TiO$_2$ $+Al_2$$O_3$). Tungsten was present mainly at the lower part of the oxide scale, while Si over the whole oxide scale.

• 터널과지하공간
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• 제21권2호
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• pp.103-108
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• 2011

콘크리트 블록에 대한 붙이기 발파실험과 더불어 콘크리트 박스거더 교량의 모형에 대하여 발파해체 실험을 실시하였다. 장약으로는 폭발위력의 기준 약으로 사용되는 TNT를 사용하였다. 실험결과 콘크리트 박스거더 교량의 경우 폭약설치지점의 폭발력뿐 만 아니라 박스거더 내부 벽에 작용하는 폭풍압도 해체에 영향을 미치는 것으로 나타났다.

• 소성∙가공
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• 제15권9호
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• pp.635-640
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• 2006

Sandwich sheet with inner structure is expected to find many applications because of high stiffness to mass ratio. However, low resistance to the compressive pressure in the thickness direction is a dominating factor in the formability of sandwich sheet. In this study, sandwich sheet with pyramid type core is considered. For the compressive characteristics in the thickness direction, experiments and finite element simulations are carried out. In the experiment, deformation behavior is observed and discussed as the compression proceeds. It is shown that a corresponding finite element simulation can give a reasonable agreement with experiment in terms of maximum pressure. However, simulation shows some discrepancy from the experiment in terms of compressive pressure-displacement characteristics. The reasons for this discrepancy are studied in the geometrical imperfectness of sandwich sheet. It is also observed that most of deformation is dominated by buckling mode of pyramid legs.

• Journal of the Optical Society of Korea
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• 제12권1호
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• pp.31-37
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• 2008

To increase output power of a He-Ne laser we propose to use the capacitive rf discharge and implement four channel structure. Most of experiments were carried out with a single laser tube from this structure to optimize the output mirror transmission, pressure and composition of the mixture. A laser tube of 2.8 mm inner diameter and 50 cm discharge length can give an output power of above 5.5 mW at 3.39 ${\mu}m$. Four such tubes in "matrix" structure let us obtain 20 mW of output. Simplified models which can be used to evaluate the behavior of an equivalent electrical circuit with laser plasma and qualitative characteristics of output power of He-Ne laser were also described.

• The Journal of the Acoustical Society of Korea
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• 제29권3E호
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• pp.140-145
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• 2010

In the present study, tubular polyvinyl chloride (PVC) cortical bone mimics that simulate the cortical shell of long bones were used to validate the axial transmission technique for assessing the cortical thickness by measuring the ultrasonic velocities along the cortical shell of long bones. The ultrasonic velocities in the 9 PVC cortical bone mimics with wall thicknesses from 4.0 to 16.1 mm and inner diameters from 40 to 300 mm were measured as a function of the thickness by using a pair of custom-made transducers with a diameter of 12.7 mm and a center frequency of 200 kHz. In order to clarify the measured behavior, they were also compared with the predictions from a theory of guided waves in thin plates. This phantom study using the PVC cortical bone mimics provides useful insight into the dependencies of ultrasonic velocities on the cortical thickness in human long bones.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.402-405
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• 2006

Inner support regions of continuous steel and concrete composite bridge decks, transverse crackings are easely developed by tensile forces due to live loads and primary and secondary effects of concrete shrinkage. Since these cracks have an influence on the durability of bridge decks, crack width should be controlled within allowable limit values. Although crack width is a function of steel stress, bar diameter, bar spacing, etc, the current code for the amount of longitudinal reinforcements provides only one value of 2 percent of the concrete area. In order to investigate cracking bahaviors of composite girders with the variation of the longitudinal steel ratios, negative flexural tests are conducted on five composite girders and crack width and crack spacing are compared to ACI Code and Eurocode. Based on the test results, it is discussed the suitability of the current code for the longitudinal steel ratio.