• Earthquakes and Structures
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• 제1권3호
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• pp.307-326
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• 2010

This paper is concerned with the optimal seismic design of added viscous dampers in yielding plane frames. The total added damping is minimized for allowable values of local performance indices under the excitation of an ensemble of ground motions in both regular and irregular structures. The local performance indices are taken as the maximal inter-story drift of each story and/or the normalized hysteretic energy dissipated at each of the plastic hinges. Gradients of the constraints with respect to the design variables (damping coefficients) are derived, via optimal control theory, to enable an efficient first order optimization scheme to be used for the solution of the problem. An example of a ten story three bay frame is presented. This example reveals the following 'fully stressed characteristics' of the optimal solution: damping is assigned only to stories for which the local performance index has reached the allowable value. This may enable the application of efficient and practical analysis/redesign type methods for the optimal design of viscous dampers in yielding plane frames.

• 생명과학회지
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• 제14권1호
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• pp.57-60
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• 2004

육종재료를 얻기 위하여 부산ㆍ경남지역에서 수집된 우리나라 재래종 옥수수 49계통에 대하여 주성분분두법을 이용하여 계통간 거리를 구하였고, 이를 이용하여 계통분류를 실시하였던 바 다음과 같은 결과를 얻었다. 계통간 거리에 의해 49계통은 4개의 계통군으로 분류되었고, 계통군 I 에는 11계통, 계통군 II에는 20계통, 계통군 III에 는 14계통, 그리고 계통군 IV에는 4계통이 속하였다. 계통군 I은 조생, 단간, 소수, 소분얼형의 계통들이었고, 계통군 II는 조생, 장간, 대수, 다수, 소분얼형의 계통이었고, 계통군 III은 만생, 단간, 소수, 다분얼형 의 계통이었고, 계통군 IV는 중생, 장간, 대수, 다수, 다분얼형의 계통들이었다.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.180-189
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• 1999

This paper describes the collapse characteristics of the rectangular tube under eccentric compressive load. Local buckling stress and maximum crippling load are investigated. A thin-walled tube under load is controlled by local buckling or yielding of material according to the ratio of thickness to width (t/b) of the cross section, and subsequent collapse of the section. The relationship can be divided into three regions : elastic , post-buckling and crippling . the load-displacement relationship is theoretically presented in each region by introducing the stress distribution of the cross section in the loading process. And the maximum load carrying capacity is derived in the closed form as a function of normal stress on the flange and web.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권1호
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• pp.57-61
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• 2003

A new silkworm variety, Chugangjam, with a sex-limited larval marking and high silk yielding for summer-autumn rearing season is $F_1$ hybrid between Jam 147, a Japanese race bred from P8503/8453, and Jam 148, a Chinese race from M8306/Jam 130. Jam 147, Japanese parent of the Chugangjam showed a high GCA (general combining ability) in pupation percentage and Jam 148, Chinese parent, showed a high GCA in pupation percentage and single cocoon weight. In the local adaptability test performed at 8 local areas in autumn of 2001, Chugangjam was 5% higher in cocoon yield and 8% in raw silk productivity in the 10,000 of the 3rd molted larvae, respectively, than the check variety Daesungjam.

• 한국해양공학회지
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• 제16권5호
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• pp.66-72
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• 2002

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear power plant. However, effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. Acoustic emission(AE) has been widely used in various fields because of its extreme sensitivity, dynamic detection ability and location of growing defects. In this study, we investigated failure modes of locally wall thinned pipes and AE signals by bending test. From test results, we could be divided four types of failure modes of ovalization, crack initiation after ovalization, local buckling and crack initiation after local buckling. And fracture behaviors such as elastic region, yielding region, plastic deformation region and crack progress region could be evaluated by AE counts, accumulative counts and time-frequency analysis during bending test. The result of the frequency range is expected to be basic data that can inspect plants in real-time.

• 한국강구조학회 논문집
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• 제25권2호
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• pp.131-139
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• 2013

본 연구의 목적은 H-형강 압축재의 온도상승에 따른 파괴거동을 중심으로 압축력과 파괴온도의 상관관계를 파악하기 위한 실험을 수행하는 것이다. SS400 강재로 제작된 H-형강의 시험체를 선정하여, ISO 834의 재하가열 시험방법에 따라 온도 상승에 대한 실험을 한국방재시험연구원(FILK)에서 수행하였다. 고온상태의 강재에 대한 항복강도 및 탄성계수의 감소계수는 EC3 (Eurocode3) Part 1.2 (1993) 관계식을 근거로 하여 파괴온도시 국부 및 전체좌굴 응력도와 항복응력도를 실험결과와 비교 검토하였다. 실험조건은 세장비 45.4이고 상온에서의 항복내력에 대한 50%, 70%, 80%를 재하압축력으로 설정하여 파괴온도를 측정하였다. 파괴온도와 재하압축력에 대한 실험결과로 부터 온도상승에 따른 내력은 탄성 좌굴강도보다는 항복내력에 근접함을 파악할 수 있었다.

• Steel and Composite Structures
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• 제41권6호
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• pp.861-871
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• 2021

This study aims at investigating the hysteretic performance of a novel composite wall panel fabricated by infilling aerated concrete blocks into a novel light-steel frame used for low-rise residential buildings. The novel light-steel frame is consisted of two thin-wall rectangular hollow section columns and a truss-beam assembled using patented U-shape connectors. Two bare light-steel frames and two composite wall panels have been tested to failure under horizontal cyclic loading. Hysteretic curves, lateral resistance and stiffness of four specimens have been investigated and analyzed. Based on the testing results, it is found that the masonry infill can significantly increase the lateral resistance and stiffness of the novel light-steel frame, about 2.3~3 and 21.2~31.5 times, respectively. Failure mode of the light-steel frame is local yielding of the column. For the composite wall panel, firstly, masonry infill is crushed, subsequently, local yielding may occur at the column if loading continues. Hysteretic curve of the composite wall panel obtained is not plump, implying a poor energy dissipation capacity. However, the light-steel frame of the composite wall panel can dissipate more energy after the masonry infill is crushed. Therefore, the composite wall panel has a much higher energy dissipation capacity compared to the bare light-steel frame.

• 한국강구조학회 논문집
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• 제16권2호통권69호
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• pp.275-284
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• 2004

기둥-보 약축 접합 디테일 개발을 위해서 접합부의 거동을 파악하는 것이 선행되어야한다. 약축 접합부의 형식에 따른 강축 접합부의 거동을 파악하기위하여 기존 브라켓타입 용접접합부의 각 요소들 즉 패널존, 수평스티프너의 유무 및 위치를 변수로 고려하였다. 본 연구에서는 접합부에 수평스티프너가 있는 경우는 접합부를 수직스티프너로 보강한 단순보로 치환하여 접합부의 내력을 산정하였으며, 수평스티프너가 없는 경우는 기둥플랜지의 국부휨강도, 기둥 웨브의 국부인장강도, 기둥 웨브의 크립플링강도 및 기둥웨브의 최대 좌굴강도를 고려한 내력 평가식을 사용하였고 이론해석결과와 실험결과를 비교 분석하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.319-326
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• 2001

In this paper, 3-D frame design using refined plastic-hinge analysis accounting for local buckling is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem associated with conventional refined plastic-hinge analyses, which do not consider the degradation of the flexural strength caused by local buckling, is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are presented. In this study, a model consisting of the width-thickness ratio is used to account for local buckling. The proposed analysis is verified by the comparison of the LRFD results.

• Journal of Ginseng Research
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• 제22권1호
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• pp.11-17
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• 1998

To develop a new ginseng varieties with good quality and high yielding, a lot of individual ginseng plants were selected in the farmer's fields in 1972. Among them, a promising line, 7259-3-1, has been developed through comparative cultivation of several lines selected with pure line separation of local races in Korea Ginseng '||'&'||' Tobacco Research Institute. Preliminary and advanced yield trials were performed for 8 years. It was then designated as "KG 101" and tested in the regional yield and adaptation trials for 10 years (1981-1990). KG101 has a green stem with light violet and orange-yellow fruit and flowers 3-7 days later than local race, Takyungjong. Taproot of KG101 was longer than local race Jakyungjong, and root yield of KG101 was 9% higher than local race Jakyungjong. In red ginseng quality, the rates of Chun-Jeesam (Chun and Jee means 1st and 2nd grade, respectively) were 22.3% and 9.4% for KG101 and Jakyungjong, respectively. In these results, it was clarified that KG101 was superior ginseng line with good quality.y.