• Structural Engineering and Mechanics
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• 제52권6호
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• pp.1135-1156
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• 2014

The ratcheting effect greatly challenges the design of piping components. With the assistance of the quasi-three point bending apparatus, ratcheting and the ratcheting boundary of pressurized straight Z2CND18.12N stainless steel pipe under bending loading and vertical displacement control were studied experimentally. The characteristics of progressive inelastic deformation in axial and hoop directions of the Z2CND18.12N stainless steel pipes were investigated. The experiment results show that the ratcheting strain occurs mainly in the hoop direction while there is less ratcheting strain in the axial direction. The characteristics of the bending ratcheting behavior of the pressure pipes were derived and compared under load control and displacement control, respectively. The results show that the cyclic bending loading and the internal pressure affect the ratcheting behavior of the pressurized straight pipe significantly under load control. In the meantime, the ratcheting characteristics are also highly associated with the cyclic displacement and the internal pressure under displacement control. All these factors affect not only the saturation of the ratcheting strain but the ratcheting strain rate. A series of multi-step bending ratcheting experiments were conducted under both control modes. It was found that the hardening effect of Z2CND18.12N stainless steel pipe under previous cyclic loadings no matter with high or low displacement amplitudes is significant, and the prior loading histories greatly retard the ratcheting strain and its rate under subsequent loadings. Finally, the ratcheting boundaries of the pressurized straight Z2CND18.12N stainless steel pipe were determined and compared based on KTA/ASME, RCC-MR and the experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.2165-2166
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• 2006

Estrangement hierarchical by bipolarization is deepened and time space that social welfare by graying corresponds great so. Specially, is real condition that indifference by patient's increase which is solitary life string is come to involve by social problem.Together, Jaetaek bone fracture patient's ratio is zooming. Domestic BT technology, medical treatment solution technology offer more important role than role assistance enemy of modern technology and utilize by creative technology can. Specially, if apply supersonic waves in bone fracture treatment, there is treatise data that can reduce bone fracture treatment period of bone that bone does not stick well about 40%. Supersonic waves operation frequency used on both end because do 1m Hz, 1.3mHz, supersonic waves origination that have 1.5mHz's Piezo-ceramic crystal tranducer material each 4 premature senilitys in this research, and outside diameter according to impedance and Phase d used Gakgak4mm, 5.4mm, Dukke0.5mm, transformer deuce of length 70mm. Manufactured, and investigated supersonic waves distribution chart by capacity 50m W. Supersonic waves used by diagnosis mainly but is seen to become convenient medical treatment mounting in bone fracture patient's treatment if supplement clinically.If supplement system furthermore, is going to apply to osteoporosis patient, and this research tried to design poetic theme width directly and study rain standardization special quality and approach basic form because do modelling.

• 한국구조물진단유지관리공학회 논문집
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• 제17권1호
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• pp.1-9
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• 2013

철골구조에서 지진력 저항시스템으로 많이 사용되고 있는 가새골조시스템은 중심가새골조(Concentrically Braced Frames, CBF)와 편심가새골조(Eccentrically Braced Frames, EBF)로 구분하여 KBC2009 건축구조기준에서는 서로 다른 반응수정계수를 적용하여 설계하도록 되어있다. 현행 내진설계기준에서 편심가새골조에 대하여 링크 타단 접합부의 종류에 따라 모멘트 저항접합일 경우 반응수정계수는 R=8, 비모멘트 저항접합일 경우 반응수정계수 R=7로 적용하여 설계하도록 규정하고 있을 뿐 편심길이의 영향을 고려하지 않고 있다. 본 연구에서는 편심가새골조 중에서 역V형가새골조를 대상으로 비탄성 거동을 파악한 다음 편심길이에 따른 반응수정계수를 산정하여 내진설계 기준에서 제시한 값과 비교한 결과 편심가새골조에 대하여 동일한 반응수정계수를 적용하는 것은 적절하지 않음을 확인하였다.

• 한국자동차공학회논문집
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• 제18권2호
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• pp.83-90
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• 2010

The windshield wiper consists of 4 parts: a blade, an arm, a linkage and a motor. The wiper blade makes contact with the windshield and is designed to be operated normally at an angle of 30~50 degrees to the front glass. If the contact pressure between the wiper blade and windshield surface is too high, noise and wear of the rubber will result. On the other hand, if the contact pressure is too low, the performance will do badly, since foreign substances such as dust and stains will not be removed well. The pressure and friction of the wiper blade has a great influence on its effectiveness in cleaning the front window. This is due to the contact of the rubber with the window. This paper presents the dynamic analysis method to estimate the performance of the flat type blade of the wiper system. The blade has a nonlinear characteristic since the rubber is an incompressible hyper-elastic and visco-elastic material. Thus, Structural dynamic analysis using a complex contact model for the blade is performed to find the characteristics of the blade. The flexible multi-body dynamic model is verified by the comparison between test and analysis result. Also, the optimization using the central composite design table is performed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 춘계종합학술대회
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• pp.205-208
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• 2002

국제-국내간의 해저 광케이블을 설치할 때, 해양조사는 사전 정확한 해저지질 및 수심상태를 파악한다. 그리고 안전한 경로를 선정 및 해저 광케이블 매설을 위해서 용이한 위치론 확보하는 작업이다. 또한, PLGR는 광케이블 루트상의 해저 면의 해양 오염 물질(로프, 와이어, 그물)을 사전에 제거하여 광케이블의 해저면 안착을 용이하게 한다. 더불어서 Plough 및 ROV 매설 작업 시 매설작업 성능 향상 및 매설장비의 보호시킬 수 있는 작업이다. 따라서 된 논문은 해저 광케이블 건설 사업에서 해양조사, PLGR 작업을 위해서 선박의 정보를 관리하기 위한 모니터링 시스템에 대해서 논한다. 이를 위해서 GPS, gyrocompass, tension meter 데이터 취득을 위한 시리얼 멀티포트 통신 모듈을 구성, 수신 데이터의 관리 및 운용을 위한 실시간 처리, 그래프 및 인쇄 출력 모듈을 설계 및 구현하였다.

• 한국해안해양공학회지
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• 제15권2호
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• pp.86-96
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• 2003

방파제의 경사면에 거치된 콘크리트 피복재의 단면파괴에 대한 신뢰성 해석을 수행하였다. 신뢰함수는 피복재의 흔들림 또는 동요의 크기를 정량적으로 나타내는 회전각의 함수로 유도되었다. 방파제 단면에 거치된 피복재의 재질적 성질 및 기하학적 형상과 관련된 확률변수들의 단면파괴에 미치는 영향 정도가 자세히 해석되었다. 또한 파고의 함수로 피복재 개개의 단면파괴에 대한 파괴확률이 산정 되었다. 마지막으로 Bernoulli과정과 허용파손율의 개념을 동시에 고려하여 피복재의 단면파괴가 어떻게 방파제 제체의 파괴확률로 이어지는가가 해석되었다. 허용파손율 개념은 본 연구에서 도입된 것으로, 허용파손율을 어떻게 정의하느냐에 따라 피복재의 단면파괴에 의하여 유발되는 방파제 제체의 파괴확률이 다르게 거동되는 것을 확인할 수 있었다 따라서 상대적으로 수심이 깊은 곳에 중량이 큰 콘크리트 피복재를 사용하여 방파제를 설계할 때는 수리학적 안전성뿐만 아니라 구조적 안전성도 중요하게 고려되어야 한다.

• 폴리머
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• 제36권4호
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• pp.470-477
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• 2012

다양한 아민 그룹으로 개질된 다중벽 탄소나노튜브(이하 MWNT) 지지체를 기반으로 하여 페놀 화합물을 검출하기 위한 티로시나아제가 고정된 바이오센서를 개발하였다. 방사선 중합법을 이용하여 MWNT에 글리시딜메타크릴레이트를 중합한 후 중합 사슬의 아미노화 반응을 통해 MWNT에 다양한 아민 그룹을 도입시켰다. 이렇게 제조된 물질의 물리적, 화학적 특성은 SEM, XPS 그리고 TGA에 의해 평가되었다. 그리고 제조된 물질을 기반으로 제작된 티로시나아제가 고정화된 바이오센서의 전기화학적 특성도 평가하였다. 본 효소 바이오센서는 0.1-0.9 mM의 페놀을 검출할 수 있다. 결합효과, pH, 온도 그리고 다양한 페놀화합물에 대한 반응과 같은 여러 가지 변수에 대하여도 최적화하였고 상용 레드와인에서의 페놀화합물 검출도 연구하였다.

• 한국유체기계학회 논문집
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• 제14권3호
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• pp.23-27
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• 2011

Due to a roots type medium vacuum pump is operated in condition of $1{\sim}10^{-3}$ torr vacuum, it could be applied for production and process of industrial parts, such as precise processing, vaporization, enrichment, separation, casting, metaling, welding, transportation. Therefore, the demand of this pump is increasing nowadays in our industrial markets of semiconductor, electric, electronic, automobile, material, environmental and transporting industries. However, the pumps are almost imported, because the domestic pumps are inferior in fields of vacuum range as under $10^{-1}$torr, relevant techniques(design, fabrication, casting, test, etc.) to the imported ones. In this study, essential parts of the development pump are designed with using of CFD and 3D decodes, FEM for analysing strength and deformation, generated heat, vibration and noise control, and are casted with using of mechanochemistry techniques for decreasing of weights, increasing of heat resistances and abrasion durability of materials for pump caing and impellers especially. Besides, in order to achieve ultimate vacuum around $10^{-3}$torr, this pump is composed of 6 stages, among which 1st stage is operated separately from remained stages. Additionally, a test rig for prototype pumps(300$m^3/h$ and 2,500$m^3/h$) is designed and procured as to apply for multi-staged rootz type vacuum pump, with modification of the test method recommended by KS B 6314 "Positive-displacement oil-sealed rotary vacuum pumps".

• Geomechanics and Engineering
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• 제11권1호
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• pp.77-94
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• 2016

A forked tunnel, as a special complicated underground structure, is composed of big-arch tunnel, multi-arch tunnel, neighborhood tunnels and separate tunnels according to the different distances between two separate tunnels. Due to the complicated process of design and construction, surrounding jointed rock mass stability of the big-arch tunnel which belongs to the forked tunnel during excavation is a hot issue that needs special attentions. In this paper, an elasto-plastic damage constitutive model for jointed rock mass is proposed based on the coupling method considering elasto-plastic and damage theories, and the irreversible thermodynamics theory. Based on this elasto-plastic damage constitutive model, a three dimensional elasto-plastic damage finite element code (D-FEM) is implemented using Visual Fortran language, which can numerically simulate the whole excavation process of underground project and perform the structural stability of the surrounding rock mass. Comparing with a popular commercial computer code, three dimensional fast Lagrangian analysis of continua (FLAC3D), this D-FEM has advantages in terms of rapid computing process, element grouping function and providing more material models. After that, FLAC3D and D-FEM are simultaneously used to perform the structural stability analysis of the surrounding rock mass in the forked tunnel considering three different computing schemes. The final numerical results behave almost consistent using both FLAC3D and D-FEM. But from the point of numerically obtained damage softening areas, the numerical results obtained by D-FEM more closely approach the practical behaviors of in-situ surrounding rock mass.

• 대한건축학회논문집:계획계
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• 제35권7호
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• pp.81-88
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• 2019

The purpose of this study is to investigate the relations between brick and stone brick pagodas in all classes of pagoda with their construction and shape. Research objects of this study are brick and stone brick pagodas of National Treasure and Treasure and masonry pagodas that are similar to brick and stone brick pagoda. This study includes checking preceding researches, drawing questions from these preceding researches, and finding answers from these questions. The results of this study are as follows. First, pagoda of Bunhwangsa Temple, the first pagoda in the Silla Dynasty, was built as a masonry pagoda, not a stone brick pagoda. Second, roofs of stone brick pagoda barrows from brick pagoda's techniques for performance of material and ease construction. Third, brick or stone brick pagodas' base have Type II that has low and extensive foundation with soil and stones usually. Forth, Korean pagodas are categorized by their materials, construction methods, and shapes. Wooden pagodas, stone pagodas, and brick pagodas are categorized by materials, post-and lintel pagodas and masonry stone pagodas are categorized by construction methods, and pitched roof pagodas and terraced roof pagodas are categorized by shapes. Fifth, masonry pagodas of Buddhism that have shape of multi-story building were developed from Doltap, traditional stone stack, and they advanced with brick pagodas and stone pagodas to terraced roof stone pagodas and post-and lintel base brick pagodas.