• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.127-134
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• 1999

An optimization algorithm based on Genetic Algorithm(GA) is developed for discrete optimization of reinforced concrete plane frame by constructing databases. Under multiple loading conditions, discrete optimum sets of reinforcements for both negative and positive moments in beams, their dimensions, column reinforcement, and their column dimensions are found. Construction practice is also implemented by linking columns and beams by group ‘Connectivity’between columns located in the same column line is also considered. It is shown that the developed genetic algorithm was able to reach optimum design for reinforced concrete plane frame construction practice.

• 한국전산구조공학회논문집
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• 제33권3호
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• pp.153-158
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• 2020

본 논문에서는 부분 CFST (concrete-filled steel tube) 기둥에 대한 수치해석적 저항력 평가 방법에 대해 소개하고 있다. 기존 RC(reinforced concrete) 기둥에서 소성힌지가 발생할 것으로 예상되는 부분을 강관으로 보강함으로써 완전 CFST 기둥보다는 적은 재료를 사용하여 비슷한 휨 모멘트 저항력을 가지는 부분 CFST 기둥의 디자인 컨셉을 제시하였다. 부분 CFST 기둥에서 외부 강관과 내부 콘크리트 사이의 계면에서 거동을 수치해석적으로 모사하기 위해 개선된 부착슬립모델을 적용한 유한요소모델을 구축하고, 이중곡률 휨-압축시험결과와 비교를 통해 타당성을 검증하였다. 검증된 수치모델을 바탕으로 매개변수 연구를 통해서 P-M 상관도를 그려 단면 조건에 따른 최대 저항력을 평가하였다. 또한, 강관 두께별로 필요 보강길이를 산출하고, 보강 조건에 따른 부분 CFST 기둥에서의 파괴메커니즘을 분석하였다.

• 한국강구조학회 논문집
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• 제10권2호통권35호
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• pp.153-160
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• 1998

각형 강관(${\boxe}-75{\times}75{\times}3.2,\;{\boxe}-100{\times}100{\times}4.2,\;{\boxe}-125{\times}125{\times}6.0$) 기둥의 단면 치수와 초기 변형을 측정하였다. 인장시험, 단주 압축강도 실험, 그리고 세장비 $46{\sim}84$ 사이의 기둥에 대한 압축강도 실험을 수행하였다. 유한요소법에 의한 기둥의 압축 강도를 산출하였다. 단면의 공칭 치수에 대한 측정값의 오차는 무시할 정도이며, 초기변형은 각 단면별로 세장비 100에 해당하는 기둥길이에 대해 초과 확률 2.5% 값이 각각 1/490, 1/1121, 1/1395로 나타났다. 인장시험 결과 강재의 항복강도는 최소 규정 강도보다 30% 이상 높다. 기둥 실험 결과 얻은 각형 강관 기둥의 압축강도는 단주 압축강도를 강재의 항복강도로 간주하고 비교하면 유한요소 해석 결과나 AISC, Eurocode의 강도 곡선과 거의 같거나 약간 높은 값이나, 강재의 최소 규정강도를 기준으로 비교하면 실험 결과가 훨씬 높은 강도를 보이는 것으로 나타났다.

• Steel and Composite Structures
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• 제50권5호
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• pp.499-513
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• 2024

This paper describes the experimental and numerical investigations of octagonal Concrete-Filled Double Skinned Steel Tube (CFDST) short columns under the influence of various internal sizes of the circular and square steel tubes, with constant cross-sectional dimensions of the external octagonal steel tube under concentric loading. The non-linear finite element analysis of octagonal CFDST columns was executed using the ABAQUS to forecast and compare the axial compression behavior influenced by the various sizes of internal circular and square steel tubes. The study shows that the axial compressive strength and ductility of octagonal CFDST columns were significantly influenced by various internal dimensions of the circular and square steel tubes with the strengths of constituent materials.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.7.1-7.4
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• 2024

The document "Understanding the Relationship Between Particle Size, Performance, and Pressure" explores the impact of particle size on chromatographic performance and system pressure. The study highlights how smaller particles can improve separation efficiency by providing higher resolution and faster analysis times. However, this comes at the cost of increased backpressure, which can challenge the system's hardware and require higher operating pressures. The document discusses the balance needed between particle size, column dimensions, and system pressure to optimize performance without exceeding the pressure limits of chromatographic systems. It outlines the advantages of using superficially porous particles (SPPs) over fully porous particles (FPPs) in achieving high efficiency with lower backpressure. The study also emphasizes the importance of selecting appropriate column dimensions and flow rates to manage system pressure while maintaining optimal performance. In conclusion, understanding the interplay between particle size, performance, and pressure is crucial for optimizing chromatographic separations, ensuring system longevity, and achieving high-quality analytical results.

• 복합신소재구조학회 논문집
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• 제6권3호
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• pp.77-85
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• 2015

In this paper, we present the result of investigations pertaining to the elastic buckling of simply supported columns with various cross-sectional dimensions but the same length and volume. In the investigations the accuracy of the analysis methods is studied and it was found that the result obtained by the successive approximations technique is the most accurate. In addition, the elastic buckling loads of columns with variable cross-section dimensions are obtained by the theoretical and numerical methods. From the results, it was found that the buckling loads obtained by the numerical methods are close to the buckling loads obtained by the successive approximations technique for the practical standpoints. Moreover, the buckling load of column with convexity in its middle is the highest while the buckling load of the tapered column is the lowest as expected.

• Steel and Composite Structures
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• 제17권1호
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• pp.83-103
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• 2014

The objective of this research is to study the ultimate moment capacity of the connections between steel I-beams and concrete-filled steel tube columns using different stiffener configurations. The main parameters considered are column cross section shape, square or circular, and filling the column with concrete. This analytical study includes finite element models using ANSYS program taking geometric and material nonlinearities into consideration. These models are verified against the experimental results obtained from previous researches and current design guides. The results show that using proper stiffener configuration affects the stress distribution through the connection and increases the ultimate moment capacity of the connections. Also, circular column is advantageous than the square column for all stiffener configurations and dimensions.

• 한국정밀공학회지
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• 제12권1호
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• pp.87-96
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• 1995

A new fungivle material named Epoxy-Granite composite is applied to the column structure of drilling center in order to investigate the advanced dynamic charateristics comparing with a conventional cast iron material. The dimensions of new column structure are adjusted to keep the same stiffness (EI value) and the manufacturing conditions are formulated based on the preceeding research experience about the development of Epoxy-Granite structural material. The two kinds of experiments are set up, one of which is for the measurement of natural mode and frequency using experimental modal analysis, and the other one is for the measurement of vibration amplitude during idling operation of a machine tool. The comparison of maximum accelerance values at each natural frequency of bending mode shows a Epoxy-Granite column have larger modal damping ratios(over 2times) than a cast iron column. The vibration amplitude of Epoxy-Granite column measrued on the bed, motor base, and top of column are also much smaller (up to 12%) than the case of cast iron column. It is therefore confirmed that a Epoxy-Granite material exhibits a good anti- vibrational propderty even if it is used under the actual operational environments of machine tool as a practical structural element.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 춘계학술대회 논문집
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• pp.158-165
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• 1995

A new fungible materal named Epoxy-Granite composite is applied to the column structure of drilling center in order to investigate the advanced dynamic chatateristics comparing with a conventional cast iron material. The dimensions of new colum structure are adjusted to keep the same stiffness (El value) and the manufacturing conditions are formulated based on the preceeding research experience about the development of Epoxy-Granite structural material. The two kinds of experiments are set up. one of which is for the measurement of natural mode and frequency using experimental modal analysis and the other one is for the measurement of vibration amplitude during idling operation of a machine fool. The comparison of maximum, accelerance values at each natural frequency of bending mode shows a Epoxy-Granite column have larger modal damping ratios(over 2times) than a cast iron column. The vibration amplitude of Epoxy-Granite column measued on the bed motor base and top of column are also much smaller (up to 12%) than the case of cast iron column. It is therefore confirmed that a Epoxy-Granite materal exhibits a good anti-vibrational property even if it is used under the actual operational environments of machine eool as a practical structural element.

• Structural Engineering and Mechanics
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• 제89권2호
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• pp.155-170
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• 2024

Several types of column-beam connections are used in the design of steel structures. This situation causes different cross-section effects and, therefore, different displacements and deformations. In other words, connection elements such as welds, bolts, continuity plates, end plates, and stiffness plates used in steel column-beam connections directly affect the section effects. This matter reveals the necessity of knowing the steel column-beam connection behaviours. In this article, behaviours of bolted column-beam connection with end plate widely used in steel structures are investigated comparatively the effects of the stiffness plates added to the beam body, the change in the end plate thickness and bolt diameter. The results obtained reveal that the moment and force carrying capacity of the said connection increases with the increase in the end plate thickness and bolt diameter. In contrast, it causes the other elements to deform and lose their capacity. This matter shows that optimum dimensions are very important in steel column-beam connections. In addition, it has been seen that adding a stiffness plate to the beam body part positively contributes to the connection's moment-carrying capacity.