• 한국지반공학회논문집
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• 제24권12호
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• pp.33-40
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• 2008

본 연구에서는 유한요소해석을 이용하여 암반에 근입된 현장타설말뚝의 말뚝-지반 상호작용즉, 지반의 연속성을 고려한 하중전이해석을 수행하였다. 이를 위하여 주면 하중전이함수를 사용자 정의의 경계면 모델(FRIC)로 구현하여 말뚝지반의 미끄러짐 거동과 하중전이 거동을 모델링 하였다. 본 연구결과, 주면마찰력에 의해 발생되는 선단침하량으로 대변되는 지반 연속성 영향은 주면마찰력이 극한상태로 도달할 때까지 증가함을 알 수 있었으며, 말뚝직경과 암반계수의 비(D/$E_{mass}$), 전체하중에서 주면마찰력의 비($R_s$/Q)에 영향을 받는 것으로 나타났다. 현장재하시험 사례와의 비교분석 결과, FRIC을 이용한 유한요소해석방법은 말뚝의 하중전이 거동과 말뚝-지반 상호작용 효과(coupling effect)를 적절히 나타낼 수 있었으며, 말뚝의 거동을 예측하는데 크게 개선되었음을 확인하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.159-166
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• 2000

Non-destructive out-hole tests, impact-echo and impact-response are widely applied to evaluate integrity of drilled shafts. In these tests, vibratory motions of drilled shafts are interpreted, which induced by impacts on the shaft head. In applying the tests to evaluating integrity of shaft, it has been attended whether the tests have resolutions enough to distinguish existence of slime at between the shaft end and a bearing soil deposit. To distinguish existence of slime by tests, modes of shaft vibrations need to be reasonably interpreted, which generally vary according to a shaft boundary condition such as, a free-free or a free-fixed condition. The boundary condition of a shaft is, however, found to be significantly affected by stiffness of soil deposits around shaft as well as penetration depths of shaft into a bearing soil deposit. Thus, these effects on the boundary condition of a shaft should be considered reasonably in interpreting test results to decide the existence of slime. To investigate the effects, in this study, vibratory motions of shafts constructed in various soil conditions and end penetration depths are examined analytically. Based on the studies, variations of boundary condition are characterized in terms of soil stiffness contrast between a shaft perimeter and a shaft end, and also the ratio of a penetration depth to a shaft length. The results can be applied to verify the applicability of tests to identify the slime.

• 한국생산제조학회지
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• 제19권5호
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• pp.667-671
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• 2010

The study was aimed at developing a power transmission coupling that is possible to transfer power without any trouble even if the two rotating shafts are making minute misalignment. The coupling that has been developed is Flange Flexible Urethane-key Coupling that connects two shafts by flanges with Urethane-key. A model coupling for use in transmitting power of 10hp was made and undergone performance evaluation and tests. Property and usefulness was proved through the test. The performance evaluation has demonstrated a property of $11.25Kgf{\cdot}m$ of allowable torque and 28.25hp of power at 1,80Orpm, which was found to be superior compared to the performance of similar couplings. Based on the performance test, study was made also for improving the shape of the Urethane-key and was successful to make the flange in smaller outside diameter. Further application test at site has proved that the product is easy to install and maintain, and has property of absorbing minute misalignment between two shafts and vibration caused there from.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.9-16
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• 2005

The purpose of this study is to investigate the settlement characteristics of large drilled shafts embedded into bed rocks. To perform this research, 35 pile load test results for the large drilled shafts are used, because these deep foundations generally used as substructure systems for grand bridges. In case of the yield load can not be easily determined by load(P)-settlement(S) curve from the pile load test at the maximum loads, the standard settlements which can determine a yield load is established. The residual settlement equation of pile embedded in gneiss and igneous rocks is presented in this study. Also a equation is proposed to characterize the relationship between loads and elastic settlements in pile load tests on the large drilled shaft embedded into bedrock. Then, large drilled shaft's settlement characteristics are examined on pile length, pile diameter and pile's socked depth into rock at the pile tip.

• 한국운동역학회지
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• 제22권1호
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• pp.75-82
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• 2012

The purpose of this study was to suggest the proper shaft and head fitting methods of the golf club to increase the flight distance of the golf ball. Rotations per minute of the golf ball(RPM), ratio of Ball speed to club head speed(T-Ratio) and launch angle right after impact(LA), which are directly related to ball flight distance, were measured using Spectra with shutter speed of 1/1000sec at the constant head speed of 95mph which was controlled by robot golf swing machine. In order to investigate the effect of club shaft to the 3 selected variables, 10 shafts were used to make ten test clubs with one controlled club head which is the most commonly used by golf players. To measure the effect of the club head to the 3 selected variables, 6 golf club heads which are most commonly used by golfers were selected to make 6 test clubs with a controlled shaft which is one of the best known by players. The shafts and the heads were identified by statistical analysis to increase or decrease the RPM, T-ratio and LA. A proper fitting method of the selected shafts and the club head was suggested to increase the ball flight distance in golf.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.492-497
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• 2013

In this study, a parametric study is performed to investigate the squeal noise of an automobile water pump. The squeal noise studied in this paper is generated by the self-excited torsional resonance of the rotating shaft, and this noise is related to the stick-slip phenomenon of the mechanical seal in the water pump. The mechanical seal friction has the characteristics of the negative velocity-gradient. The equations of motion of multiple-degree-of-freedom torsional vibration model is constructed by the Holzer's method and then the equation is transformed to an equivalent single-degree-of-freedom torsional resonance simulation model. A squeal noise criteria is determined by the simulation model to perform the parametric study. The design parameters(the mass moment of inertia of the pulley, the mass moment of inertia of the impeller, the length of the shafts, the radius of the shafts, spinning speed of the shafts, the position of the mechanical seal, radius of the mechanical seal, and normal load of the mechanical seal) are investigated to confirm the stability for the squeal noise.

• 한국생산제조학회지
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• 제24권6호
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• pp.675-681
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• 2015

When many holes on a plane are machined simultaneously, the positional precision and machining efficiency are very important. Multi-spindle heads are typical order making products of which the number of shafts and hole positions vary depending on the size or form of the product. For the automatic design of multi-spindle heads, the design modules for power transmission systems for drive, idle, and spindle shafts were developed, and a design technique the determining the optimum position and number of idle shafts according to gear positions was developed. In addition, for the precise determination of the multi-spindle head, the design methods for the guide planes of columns, and feed mechanisms were devised. In addition, the design modules for accurate clamping and automatic transportation mechanisms were developed. Finally, in order to simplify and standardize the design process, the design analysis and simulation verification modules are integrated.

• 디자인학연구
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• 제15권1호
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• pp.81-92
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• 2002

Through network draft, it′s possible to describe curve draft with main motive in a lobby loom and to fulfill draft design more conveniently thanks to the development of computer device. Network draft was introduced by Alice Schlein, who is an American weaving artist, and I had ever published research paper on "The unfolding and development of network draft using computer dobby system" . The purpose of the next study was to develop the design of network draft while do make a design network draft in a dobby loom with 16 shafts, and could reach follow conclusion as a result of designing a variety of drafts. The initial of 4-end in a loom with 16 shafts was a basic condition to describe more perfect shape in comparison with draft in 8 shafts through the development of network. The development of draft line was essential to deride the pattern of fabric, and the pattern of draft is decided according to selecting key peg plan. Thereby, could get a variety of draft patterns derive from mix key peg plan with initial selected by developing the kind of draft line and applying diverse key peg plan. As for the variation and diversification of draft line, the shape of patters varied depending col the curve extent and connectivity of draft line and the size of curve. The pattern of network draft can be changed infinitely by free round curve of draft line. In addition, a variety of draft designs shall be developed by increasing the number of shaft, enlarging the scale of draft line, and developing more creative draft line.

• 설비공학논문집
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• 제17권4호
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• pp.325-332
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• 2005

This paper addresses the development of a scroll expander for power generation from relatively low temperature steam source. It has a double-sided orbiting scroll member so that no thrust bearing is needed to support the base plate of the orbiting scroll. Three power transmission shafts are placed at the periphery of the orbiting scroll base plate, and these shafts can also function as anti-rotation devices. Final output is obtained from the main central shaft engaged with the three power transmission shafts through gear assembly. The clearance between the fixed and orbiting scroll elements was estimated by comparing measurement of the mass flow rate with calculation results of a computer simulation. Due to large clearance, the expander total and volumetric efficiencies were measured to be $34\%\;and\;43\%$, respectively. It has been shown through the computer simulation that the total and volumetric efficiencies could be improved to $65\%\;and\;83\%$, respectively, if the current clearance is reduced by half.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.883-888
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• 2008

Various effluents generated in cooking processes contribute a great deal to indoor air pollution among many other indoor pollutants such as dusts from outdoor and carbon dioxide from human body. Kitchen exhaust hoods are not believed to exhaust indoor contaminants properly in many cases, while generating too much noise. Instead of focusing on individual products of kitchen hoods, we should address the problem by attacking the ventilation system as a whole including vertical shafts and building air-tightness. In this study, it is intended to investigate the pressure distribution along the vertical shaft depending on various system parameters, such as shaft size, concurrent hood usage rate, roof fan, inlet pressure loss, and outdoor temperature. The maximum static pressure in the vertical shaft has been obtained using the method of design of experiments and analyzed by the analysis of variance. The results can be used for the design of kitchen exhaust systems by analyzing the pressure distributions in vertical shafts.