• 한국공간구조학회논문집
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• 제7권3호
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• pp.153-165
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• 2007

연성 구조물은 축강성은 강하고 휨 강성이 매우 작은 재료를 주 구조재로 사용하므로 초기강성에 매우 민감한 구조체이다. 막 구조물을 설계하기 위해서는 우선 초기장력 도입으로 인한 구조물의 형상을 정확히 알아야 한다. 이를 위해서 모형을 통한 모델링이나 컴퓨터를 이용한 형상해석이 요구되며, 초기장력의 도입으로 형성되는 막 구조물의 곡면은 일반적으로 등장력 곡면이다. 따라서 연성 구조물의 해석과 설계는 기존의 강성구조물과는 다른 형상해석, 응력-변형해석, 재단도 작성 및 시공해석의 3단계 해석이 요구되어진다. 본 연구는 재단도 작성 프로그램 NASScut를 이용하여 경계면 곡률의 오차를 최소화 할 수 있는 삼각형 Re-mesh 패턴을 제안하고, 재단도를 작성한다.

• 한국강구조학회 논문집
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• 제25권1호
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• pp.25-34
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• 2013

매닮 데크플레이트를 이용한 슬래브의 휨거동을 실험적으로 조사하기 위한 것이 본 논문의 목적이다. 슬래브의 휨성능을 평가하기 위한 실험의 주요 변수로는 데크의 춤과 두께, 스팬, 철근보강 유무 및 단부지지 조건(단순, 고정) 이다. 이러한 슬래브에 수직하중이 작용하도록 총 6개의 실험체를 제작하여 실험하였다. 실험결과, 주요변수와 관계없이 슬래브의 내력은 수직방향 휨변형에 의해 지배됨을 알 수 있다. 또한, 리브단면 내에 휨철근이 배근된 실험체가 초기강성 및 균열강성, 휨강도 측면에서 상당히 높게 평가됨을 알 수 있다. 이론값과의 내력 비교결과, 평균 1.05로 상당히 잘 일치하는 것으로 나타났다.

• 대한기계학회논문집A
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• 제40권1호
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• pp.81-86
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• 2016

밸브는 배관의 유량을 차단 및 제어하기 위한 장치로써 게이트 밸브, 글로브 밸브, 체크 밸브 등 많은 종류가 사용되고 있다. 그 중 글로브 밸브는 고압력 조건에서의 유량조절이 용이하여 LNG 선박, 증기 배관 등에 사용된다. 본 논문에서는 글로브 밸브의 누설 문제를 구조적으로 해결하기 위해 시트의 형상을 변형하는 방법을 제시하였다. 또한 유한 요소 해석을 통해 각 모델의 응력분포와 변형량을 비교하고 이를 통하여 제안한 모델에 대한 검증을 진행하였다. 시뮬레이션 결과 제안된 모델에서 원주 방향의 변형이 줄어들고, 누설을 감소시킬 수 있는 Self-supporting 효과를 확인할 수 있었다.

• Steel and Composite Structures
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• 제21권2호
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• pp.267-287
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• 2016

The seismic performance of the ordinary steel reinforced concrete (SRC) columns has no significant improvement compared to the reinforced concrete (RC) columns mainly because I, H or core cross-shaped steel cannot provide sufficient confinement for core concrete. Two improved SRC columns by constructing with new-type shaped steel were put forward on this background, and they were named as enlarging cross-shaped steel and diagonal cross-shaped steel for short. The seismic behavior and carrying capacity of new-type SRC columns have been researched theoretically and experimentally, while the shear behavior remains unclear when the new-type columns are joined onto SRC beams. This paper presents an experimental study to investigate the shear capacity of new-type SRC joints. For this purpose, four new-type and one ordinary SRC joints under low reversed cyclic loading were tested, and the failure patterns, load-displacement hysteretic curves, joint shear deformation and steel strain were also observed. The ultimate shear force of joint specimens was calculated according to the beam-end counterforce, and effects of steel shape, load angel and structural measures on shear capacity of joints were analyzed. The test results indicate that: (1) the new-type SRC joints display shear failure pattern and has higher shear capacity than the ordinary one; (2) the oblique specimens have good bearing capacity if designed reasonably; and (3) the two proposed construction measures have little effect on the shear capacity of SRC joints embedded with diagonal cross-shaped steel. Based on the mechanism observed from the test, the formulas for calculating ultimate shear capacity considering the main factors (steel web, stirrup and axial compression ratio) were derived, and the calculated results agreed well with the experimental and simulated data.

• 한국정보통신학회논문지
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• 제15권11호
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• pp.2493-2499
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• 2011

나노 바이오산업의 발전과 더불어 세포 성장 과정에서 발견되는 세포의 이동, 분열, 통합, 아포토시스(apoptosis), 모양 변형, 세포들 간의 상호 작용 등을 포함하는 세포의 행동을 분석하기 위한 자동화된 시스템의 개발은 매우 중요하다. 본 연구에서는 세포 배양 과정에서 광학현미경을 통해 얻은 세포의 실시간 이미지들의 변화/변형 과정을 2D 또는 3D 분석 하기위한 전처리 방법과 세포와 클러스터(둘 이상의 세포의 결합)를 자동 식별하기 위한 방법, 시간의 흐름에 따라 변화되는 세포와 클러스터의 개수를 계수하기 위한 방법을 제시한다. 제안된 방법들은 30분 간격으로 촬영한 3T3 세포 배양 이미지들을 이용하여 실험하였으며 세포 및 클러스터를 분류하고 각각의 개수를 자동계수한 결과 평균 99.8%의 정확도를 보여 주었다.

• 한국정밀공학회지
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• 제29권12호
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• pp.1272-1278
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• 2012

The micro barrier rip array structures have been applied in a variety of areas including as privacy films, micro heat sinks, touch panel and optical waveguide. The increased aspect ratio (AR) of barrier rip array structures is required in order to increase the efficiency and performance of these products. There are several problems such as burr, defect of surface roughness and deformation and breakage of barrier rip structure with machining high-aspect ratio micro barrier rip array structure using orthogonal cutting method. It is essential to develop technological methods to solve these problems. The optimum machining conditions for machining micro barrier rip array structures having high-aspect ratio were determined according to lengths ($200{\mu}m$ and $600{\mu}m$) and shape angles ($2.89^{\circ}$ and $0^{\circ}$) of diamond tool, overlapped cutting depths ($5{\mu}m$ and $10{\mu}m$), feed rates (100 mm/s) and three machining processes. Based on the optimum machining conditions, micro barrier rib array structures having aspect ratio 30 was machined in this study.

• 한국정밀공학회지
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• 제29권12호
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• pp.1331-1339
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• 2012

Safety valve used in LNG/LNG-FPSO ships is a high value valve, and it plays an important role in maintaining a fixed level of pressure by emitting LNG gas out of pipes in LNG piping system under the cryogenic and high-pressure condition when the pressure of the system connected with the LNG storage tank and pipes reaches over the set pressure. The structural stability is required for the inner pressure and thermal load because of the cryogenic and high-pressure condition, and a reliability of the safety valve is necessary for impact and deformation by opening the valve. But, the safety valve, which plays a key role for a safety of the transport and storage system, is depended on imports for over 90%, and in domestic production, the design of the valve is performed on the basis of experiences of the works without quantitative analysis for the inner operation characteristics and structural stability of the valve. In this study, impact velocity is calculated by theoretical analysis for obtaining the structural stability of the guide according to the impact load by opening the valve. The shape of the guide and the diaphragm for satisfying the structural stability are suggested and verified by using a thermal-structural analysis.

• Composites Research
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• 제30권5호
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• pp.280-287
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• 2017

복합재 후퇴익은 비행 중 굽힘 하중 외에도 비틀림 하중을 받아 복잡한 변형이 발생할 수 있다. 따라서 복잡한 변형이 나타나는 복합재 후퇴익의 구조 건전성 평가를 위해 복합재 후퇴익 구조물의 변위 예측이 요구된다. 날개의 변위 예측은 변위와 변형률 관계를 통해 예측할 수 있지만 후퇴익의 복잡한 변형으로 고정단 부근의 변형률 분포는 복잡하게 나타나기 때문에 일부 위치의 변형률 센서만으로 변형률을 측정하면 변위 예측의 오차가 발생할 수 있다. 본 논문에서는 복잡한 변형률 분포를 고려한 평판 형태의 복합재 후퇴익의 변위를 예측하는 연구를 수행하였다. 유한요소 해석을 통해 변형률 측정 지점을 선정하였다. 측정 지점의 변형률을 이용하여 예측한 변위는 해석에서 계산된 변위와 잘 일치하였으며, 실험을 통하여 검증하였다.

• 한국공간구조학회논문집
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• 제20권2호
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• pp.39-49
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• 2020

In this study, we will develop a hybrid cross-sectional shape of steel inserted type glued-laminated timber that can improve the strength of structural glued-laminated timber and maximize the ductility by using steel plate with excellent tensile and deformation ability. A total of three specimens were fabricated and the flexural performance test was carried out to evaluate the structural performance of the steel inserted type glued-laminated timber. In order to compare the effect of steel inserted glued-laminated timber, one structural glued-laminated timber test specimen composed of pure wood was manufactured. In addition, in order to evaluate the adhesion performance of the steel inserted, one each of a screw joint test specimen and a polyurethane joint test specimen was prepared. As a result, all the specimens showed the initial crack in the finger joint near the force point. This has been shown to be a cause of crack diffusion and strength degradation. The use of finger joints in the maximum moment section is considered to affect the strength and ductility of the glued-laminated timber beam. Polyurethane-adhesive steel inserted glued-laminated timber showed fully-composite behavior with little horizontal separation between the steel plate and glued-laminated timber until the maximum load was reached. This method has been shown to exhibit sufficient retention bending performance.

• 대한기계학회논문집A
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• 제22권3호
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• pp.529-539
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• 1998

A quantitative study of impact damage of ${Al_2}}O_3}-TiO_2$ plasma coated soda-lime glasses was carried out and compared with that of the uncoated smooth glass specimen. The shape of cracks by the impact of steel ball was observed by stereo-microscope and the decrease of the bending strength due to the impact of steel ball was measured through the 4-point bending test. At the low velocity, cone cracks were occurred. As the impact velocity increases, initial lateral cracks were propagated on the slanting surface of a cone crack, and radial cracks were generated at the crushed site. When the impact velocity of steel ball exceeds the critical velocity, the contact site of specimen was crushed due to plastic deformation and then radial and lateral cracks were largely grown. Crack length of coated specimens was smaller than that of uncoated smooth specimen due to the effect of coating layer on the substrate surface. According to impact velocity, the bending strength of coated specimens had no significant difference, compared with that of the uncoated smooth specimen. But this represents that the bending strength of coated specimens was increased, considering the effect of sand blasting damage which was performed to increase the adhesion force of coating layer.