• Structural Engineering and Mechanics
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• 제44권5호
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• pp.649-661
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• 2012

An experimental research was conducted to investigate the strength of biaxially loaded short and slender reinforced concrete columns with high strength concrete. In the study, square and L-shaped section reinforced concrete columns were constructed and tested to obtain the load-deformation behaviour and strength of columns. The test results of column specimens were analysed with a theoretical method based on the fiber element technique. The theoretical ultimate strength capacities and the test results of column specimens have been compared and discussed in the paper. Besides this, observed failure mode and experimental and theoretical load-lateral deflection behaviour of the column specimens are presented.

• Structural Engineering and Mechanics
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• 제66권4호
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• pp.439-444
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• 2018

This paper presents a numerical study on the behavior of continuous hollow steel beam strengthened using carbon fiber reinforced polymers (CFRP). Most previous studies on the CFRP strengthening of steel beams have been carried out on the steel beams with simple boundary conditions. No independent study, to the researcher's knowledge, has studied on the CFRP strengthening of square hollow section (SHS) continuous steel beam. However, this study explored the effect of the use of adhesively bonded CFRP flexible sheets on the behavior of the continuous SHS steel beams. Finite Element Method (FEM) has been employed for modeling. Eleven specimens, ten of which were strengthened using CFRP sheets, were analyzed under different coverage length, the number of layers, and the location of CFRP composite. ANSYS software was used to analyze the SHS steel beams. The results showed that the coverage length, the number of layers, and the location of CFRP composite are effective in increasing the ultimate load capacity of the continuous SHS steel beams. Application of CFRP composite also caused the ductility increase some strengthened specimens.

• 전기의세계
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• 제13권3호
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• pp.38-41
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• 1964

This thesis is aimed to obtain efficiently economically any desired phases and single phase transformer without unbalance by using only a new transformer, applying the theory of rotating magnetic field. The brief construction and principle is as floow: two pieces of similar ring cores, triangular cores or polygonal cores are located on the upper and lower sides with equidistance. And the some number of similar leg cores, shaped a square-pillar or a sylinder, are arranged at equidistant of the core section. Ring windings or polyphase windings of AC machines are adopted as a winding method on the upper and lower cores. Three phase AC is applied to the primary windings on these cores so that the rotating magnetic field is induced on the cores and this magnetic fluxes pass through each of the secondary windings on the leg-cores with some difference in time.

• 전산구조공학
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• 제9권1호
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• pp.115-123
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• 1996

본 논문은 기하학적 비선형과 재료적 비선형을 고려하여 강구조 부재 및 골조의 비선형 해석을 위한 프로그램을 개발하고 강재의 응력도 변형도 관계를 정식화하였다. 본 프로그램의 효율성을 검증하기 위하여 단조 하중을 받는 H형강 보와 각형강관 기둥, 그리고 반복 수평력을 받는 브레이스 강재 라멘에 대한 수치해석을 행하였다. 본 그로그램에 의해 얻어진 결과는 대체적으로 기존의 실험 및 해석결과와 일치하였다.

• Steel and Composite Structures
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• 제4권1호
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• pp.1-8
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• 2004

Tests on steel tubular columns of square, rectangular and circular section filled with normal and lightweight aggregate concrete were conducted to investigate the failure modes of such composite columns. Thirty-six full scale columns filled with lightweight and normal weight aggregate concrete, eighteen specimens for each, were tested under axial loads. Nine hollow steel sections of similar specimens were also tested and results were compared to those of filled sections. The test results were illustrated by a number of load-deflection and axial deformation curves. The results showed that both types of filled columns failed due to overall buckling, while hollow steel columns failed due to bulging at their ends (local buckling). According to the above-mentioned results, and due to low specific gravity and thermal conductivity of the lightweight concrete the further interest should be concentrated in replacing the normal concrete by the lightweight aggregate concrete.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.198-200
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• 1993

This paper represents the experimental results of electrohrdrodynamic(EHD) micropump driven by traveling- wave voltage. We fabricated 60 electrodes array with $100{\mu}m$ width and $100{\mu}m$ interval on the pyrex glass. On that glass we fabricated the micro channel which had the cross section of 3mm by 0.5mm. This pump was driven by 6 phase square traveling-wave voltage. We used the corn oil for experiments and increased the temperature of fluid by resistive heater. An optical microscope with CCD camera and monitor was used for observation. The fluid velocity was large for the large driving voltage and the high temperature. This EHD pump had the fluid velocity in specific frequency (near 1Hz) which had relation to the charge relaxation time in that oil.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.864-868
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• 1988

During the 1980s, the use of high-speed printing and copying machines which will not tolerate much variation in paper weight has increased. As a result, there is a growing demand for improved basis weight control systems for paper machines. Basis weight, the weight of a square meter sheet of paper, is the most important measure of paper consistency. Until quite recently, basis weight could only be controlled manually; this required experienced operators. The reasons for the difficulty in automating control of basis weight is due to the complexity and variability of process characteristics, the "noisiness" of the process (process disturbances), and actuator inadequacies. This paper describes a method of automatic control that we have developed; it incorporates the experience of expert operators, and the results of simulation, in confidence factors.e factors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1434-1437
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• 2003

Sometimes open holes are required for the function and the weight reduction of structure and machinery. However, the serious stress concentration occurs because of the geometric discontinuity caused by the holes and cutting section. In this study, it is attempted to obtain the stress concentration coefficients of the inner surface of the hole boundary by changing the position and the shape of holes on the homogeneous isotropic plate. And the effects on the plate are investigated. The results show that the stress level becomes low and the distribution area widens the position of stress concentration changes as the ratio a/b increases and change to a circle. And as the ratio a/l decreases, the stress concentration reduces. As the plate with three holes. the stress $\sigma$$\_$x/ and $\tau$$\_$xy/ of hole 1,3 becomes high, especially $\sigma$$\_$x/ dominant and high.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1902-1906
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• 2003

Micro-milling is an efficient method for fabricating micro structures because of its high machining rate compared with other non-conventional micro machining processes. But it is not easy to make a micro milling tool with less than 50 $\mu\textrm{m}$ in diameter by conventional machining. In this study, the characteristics of a micro milling tool fabricated by wire electrical discharge machining (WEDM) were studied. The workpiece is copper and stainless steel. The effects of some machining conditions such as feed rate, depth of cut, and a shape of tool were studied. The tools with D-shape and square shape in cross section were tested for machining micro grooves and 3D structures.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.771-776
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• 1998

TORT is employed for fast neutron fluence calculation at the reactor pressure vessel. KORI Unit 1 reactor at cycle 1 is modeled for this calculation. Three-dimensional cycle averaged assembly power distributions for KORI Vnit 1 at cycle 1 are calculated by using the core physics code, NESTLE 5.0. The root mean square error is within 4.3% compared with NDR (Nuclear Design Report) far all burnup steps. The C/E (Calculated/Experimental) values for the in-vessel dosimeters distribute between 0.98 and 1.36. The most updated cross-section library. BUGLE-96 based on ENDF/B-VI is used for the neutron fluence calculation. The makimum fast neutron nun calculated on reactor pressure vessel for KORI Unit 1 operated for 411.41 effgctive full power days is 1.784x10$^{18}$ n/$\textrm{cm}^2$. The position of the maximum neutron fluence in RPV wall 1/4 T is nearby 60cm below the midplane at zero degree.