반복하중을 받는 H형강 유공보의 소성 및 국부좌굴 거동

이은택,김철환,오우훈,Lee, Eun Taek,Kim, Cheol Hwan,Oh, Woo Hun 한국강구조학회 2003 韓國鋼構造學會 論文集 Vol.15 No.3

유공부재의 탄성 및 비탄성 거동을 나타내기 위하여 많은 연구가 이루어져왔으나 단축하중상태의 연구에 집중되어있는 실정이다. 또한, 국부좌굴을 고려한 유공보 설계에 대한 식들은 일반적으로 Darwin의 연구결과를 토대로 하여 사용되고 있으나, 그 연구결과가 단조하중에 집중되어있어 반복하중과 국부좌굴을 고려한 연구의 필요성이 제기되었다. 따라서, 본 연구에서는 반복하중상태에서의 7개의 원형유공보에 대한 실험이 행해졌다. 실험체의 형상 및 변수는 Darwin에 의해 제안된 설계과정에 기초를 두었다. 본 실험을 통하여, 기존 설계식의 타당성, 소성힌지의 영향, 유공 부분의 반복국부좌굴의 영향 등이 관찰 연구되었다. Many researches have been conducted to describe the elastic and inelastic behavior of H-shaped beams with web openings, and were generally concentrated on the uniaxial loading conditions. With previous research results, the formulae for the design of beams with web openings, considering local buckling, have been proposed by Darwin. Although the formulae are so simple and useful to apply to real situations, it needs more research on cyclic loading conditions. In this experimental study, a total of seven H-shaped beams with circular web openings under cyclic loading conditions were investigated. The dimension criteria were based on the formulae proposed by Darwin. The suitability of the existing design formulae, the effects of plastic hinges on beams with web openings, and the local bucking around the web openings to the beam strength under cyclic loading were also investigated through by the observations of the behavior of these beams with various dimensional openings.

Experimental Study on Structural Performance of the New Shaped Weak-Axis Connection in Full-Scale Test

이은택,Min-Joung Kang,김성배,김상섭 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

The bracket-type connection is often used for the weak-axis steel connection of H-shaped beam-to-column. However it lead to weakness of competitiveness in steel structure due to difficulty in production and installation of connection. Consequently, new shaped weak-axis connection was developed. It has a simple shape with less spot of welding points, and has advantage about showing the obvious power flow in connection points. In this study, monotonic and cyclic loading tests in full-scale were performed to evaluate structural behavior and examine on-site application. Therefore, 12 specimens (9 specimens for monotonic loading test and 3 specimens for cyclic loading test) were manufactured for the variables which are overlap length of beam end and column flange. As the results, new shaped weak-axis connection is appeared Special Moment Frame (SMF) and have excellent structural performance and workability when the parameter is over 50 mm.

반복하중을 받는 유공 H-형강 보의 소성 거동

이은택,Lee, E.T. 한국강구조학회 2001 韓國鋼構造學會 論文集 Vol.13 No.5

Darwin의 식을 근거로 하여 9개의 유공 H-형강 보의 소성영역에서의 반복 거동을 알아보았다. 이 실험을 통하여 기존의 식, 소성힌지의 효과 개구부 주위의 크랙 발생 및 파단 이후의 소겅거동을 연구하고자 한다. 이 실험의 변수는 개구부 치수, 개구부의 위치 및 갯수, 개구부간의 거리이다. 본 실험을 통하여 국부좌굴이나 개구부의 균열 발생 이후 5~10 사이클에서의 유공보의 내력은 각 실험체 최대내력의 50% 내외로 감소하는 양상을 보였고, 이러한 현상은 일반 H-형강 보의 국부좌굴 후 내력저하와 비교하여 매우 심각한 것으로 나타났다. 따라서 지진하중과 가튼 소성 반복하중에 대한 폭-두께비의 고려나 보강재의 사용 등이 검토되어야 한다. A total of nine H-shaped beams with web openings under cyclic loading condition were investigated. The dimension criteria are based on the formulae proposed by Darwin. The suitability of existing design formulae the effects of plastic hinge on beams with web openings the fracture around the web openings and the influence of cracks neighboring web openings to the beam strength under cyclic loading were also investigated through the observation of the behavior of these beams with various opening dimensions. locations numbers and spacing between the two openings.

開高健『新しい天體』論

이은택 한국일본어문학회 2007 日本語文學 Vol.32 No.-

開高健の『新しい天體』は"食"をめぐる小說風エッセイといったていのものである。全篇"食"に終始している。食いものの味を表現するのは、多くの作家がいっているように難しいことこの上ない。開高健はそれに挑戰した。"食"は死ぬまでつきまとう根源的な欲求であるのに、食談や食欲描寫や料理の話というのが、これまでの日本文學にめったに登場してこなかったという僞善的な知的フィ-ルドに果敢に挑んだわけである。もちろん"食"の表現のさまざまなデッサンを通じて文章の練習をするという意圖もあった。本稿では開高健が仕事の一分野として"食"に關する文章にいつごろから手を染めたのか、そして彼の"食"の表現へのこだわりとはどういうものであったのかに觸れてから、『新しい天體』でその"食"がどのような文體で捉えられているかを見た。そのような考察は當然、他の作家の作品では"食"の描寫が作品の核として、あるいは痛切な細部としてどう生かされているかという考察を誘い、その結果、開高健が『新しい天體』をはじめ"食"に關する文章を意識的に發表して以來、いわば"食"という私生兒は認知されたという結論をえた。そういう意味で『新しい天體』は時代に先驅けた作品といえる。

국부좌굴된 강구조부재의 비탄성 반복 거동

이은택,송금정,Lee, Eun Taik,Song, Keum Jung 한국강구조학회 2005 韓國鋼構造學會 論文集 Vol.17 No.2

Post-local buckling behavior is a very important consideration in plastic and seismic design of steel structures. It describes the structural behavior up to the final collapse state. In order to assess the actual reliability of structures under severe repeated loading, such as strong earthquakes, it is necessary to evaluate the progressive cyclic deterioration of stiffness as well as the strength and energy dissipation capacity of the structures after local buckling happens. In this study, a simple analytical model developed for predicting post-local buckling behavior for cyclic and non-proportional loading histories, has been proposed. This analytical model uses the stress resultant model based on the two surface model. Analytical moment-curvature relationship using this model compare well with the experimental results in constant amplitude cycling, and linearized energy deterioration which is very important in seismic design can be predicted from the proposed model. 소성설계에 있어서 국부좌굴 후의 거동은 매우 중요한 고려사항이며, 최종 붕괴상태에 이르는 거동을 설명한다. 지진과 같은 복잡한 하중에 대하여 구조물의 실질적인 신뢰성을 얻기 위해, 국부좌굴 이후의 구조물의 점진적인 소재의 약화와 강성과 강도의 감소, 에너지 소실능력을 평가하여야 한다. 본 연구에서는, two-surface 모델에 근거하여 반복 불비례 하중에서의 국부좌굴 후 거동을 예측하기 위하여 제시된 stress resultant model을 이용하여, 단순화된 국부좌굴해석모델을 제안하였다. 이 모델을 사용한 해석적 모멘트-곡률관계는 일정한 반복 사이클 내에서 실험결과와 적절히 부합하며, 내진설계에 있어 중요한 선형 분포된 에너지 감소를 제안 모델로부터 예측할 수 있다.

구조용 강재의 반복소성모델 분석 연구

이은택,Lee, Eun Taik 한국강구조학회 2002 韓國鋼構造學會 論文集 Vol.14 No.6

소성이론이의 연구방향은 일반적으로 두 가지 대별된다. 첫 째는 강재의 소성변형을 적절하게 나타내는 응력-변형도 관계를 정립하는 것이고, 둘 째는 위의 과정을 이용한 기법을 개발하고 구조물을 설계하는 것이다. 소성이론을 연구하는데 한 가지 중요한 문제는 복잡한 하중이력에 대하여 소성영역에서 경화재료의 거동을 묘사하는 것이다. 또한 구조물이 강한 지진이나 바람하중을 받을 경우, 비례하중보다는 복잡한 불비례하중에 의하여 영향을 받는다. 따라서 소성이론과 강재의 소성거동에 대한 연구는 불비례하중의 거동과 영향을 나타낼 수 있어야 한다. 지금까지 많은 연구자들이 이 분야에서 이론을 발표하였고, 지금도 계속하여 새로운 소성모델 연구를 하고 있다. 본 논문은 지금까지 가장 많이 쓰이고 있는 소성 모델을 two-surface 소성모델을 중심으로 분석하고 각 소성모델의 특징과 문제점을 파악하였고 앞으로의 연구과제를 제안하였다. The task of plastic theory is twofold: first, to set up relationships between stress and strain that adequately describe the observed plastic deformation of metals, and second, to develop techniques for using these relationships in studying of the mechanics of metal forming processes, and the anlaysis and design of structures. One of the major problems in the theory of plasticity is to describe the behavior of work-hardening materials in the plastic range for complex loading histories. This can be achieved by formulating constitutive laws either in the integral or differential forms. To adequately predict the response of steel members during cyclic loading, the hardening rule must account for the features of cyclic stress-strain behavior. Neithe of the basic isotropic and kinematic hardening rules is suitable for describing cyclic streess-strain behavior, although a kinematic hardening rule describes the nearly linear portions of the stabilized hystersis loops. There is also a limited expansion of the yield surface as predicted by the isotropic hardening rule. Strong ground motions or wind gusts affect the complex and nonproportional loading histories in the inelastic behavior of structues rather than the proportional loading. Nonproportional loading is defined as externally applied forces on the structure, with variable ratios during the entire loading history. This also includes the rate of time-dependency of the loads. For nonproportional loading histories, unloading may take place along a chord instead of the radius of the load surface. In such cases, the shape of the stress-strain curve has to be determined experimentally for all non-radial loading conditions. The plasticity models including two surface models ae surveyed based on a yield surface and a bound surface that represent a state of maximum stress. This paper is concerned with the improvement of a plasticity models of the two-surface type for structural steel. This is follwed by an overview of plasticity models on structural steel. Finally the need for further research is identified.

우주여행과 건강문제

이은택 한국항공우주의학협회 2019 항공우주의학 학술대회 Vol.2019 No.4

상악 제3대구치 발거후 발생한 광범위한 피하기종

이은택,민승기,오승환,이동근 大韓顎顔面成形再建外科學會 2003 Maxillofacial Plastic Reconstructive Surgery Vol.25 No.1

Subcutaneous air emphysema is a relatively uncommon phenomenon. It has been reported in both the medical and dental literature following such various procedures as rectal biopsy, nasogastric intubation, radical neck dissection, tonsillectomy, adenoidectomy, root canal treatment, dental restoration and extraction of maxillary and mandibular teeth. The most common cause involves extraction of mandibular third molar. Subcutaneous emphysema of the head, neck and thorax is a swelling caused by introduction of air into the space of the connective tissue. The clinical signs are local swelling, tenting of the skin, and crepitation on palpation. In extreme casesk, air has been reported to pass through the masticatory space into the parapharyngeal and retropharyngeal space, and penetrate into the mediastinum. If the inflowing air contains bacteria, serious infection may ensue. The first case of subcutaneous emphysema associated with a dental procedure was first reported in 1900. This emphysema is a often limited only to the spaces of head and neck, but also can involve deeper structure. This case is diffuse subcutaneous emphysema following maxillary third molar extraction with a high-speed drill.

이부성형술에서 강선 고정술과 소강판 고정술간의 안정성에 관한 임상적 연구

이은택,김수남 원광대학교 치의학연구소 2002 圓光齒醫學 Vol.11 No.2

Performing genioplasty for greater stability of the changed chin position, incision, dissection, osteotomy design and fixation are important technical considerations. Basically, wire osteosynthesis method has been used in genioplasty, but plate/screw osteosynthesis has been introduced in rigid fixation. The purpose of this study is that comparison of stability between wire and plate/screw osteosynthesis in genioplasty. In this study, the genioplasty groups were divided into three groups ; advanced genioplasty group, reduction genioplasty group, advanced with reduction genioplasty group. In wire osteosynthesis groups, there were l5patients who had advanced genioplasty, l3patients who had reduction genioplasty, and 12patients who had advanced with reduction genioplasty. In plate/screw osteosynthesis groups, there were 15patients who had advanced genioplasty, 13patients who had reduction genioplasty, and 13patients who had advanced with reduction genioplasty. Lateral cephalograms ; pre- and postoperatively, postoperatively lmonths, and at the latest follow-up(>6months); were analyzed by linear measurement to evaluate changes in position (hard tissue B, Pogonion point) and compare relapse between both groups. The results obtained were as follows : 1. In advanced groups, the horizontal relapse rate of wire group is 13.42%, 19.07%,post-OP lmonth, post-OP 6month respectively and vertical relapse rate is 19.21%, 21.78% respectively. The horizontal relapse rate of plate/screw group is 11.16%, 15.21%, respectively and vertical relapse rate is 18.36%, 20.06% respectively. There were no statistical difference between both groups. 2. In reduction groups, the horizontal relapse rate of wire group is 20.18%, 23.45%, post-OP lmonth, post-OP 6month respectively and vertical relapse rate is 28.36%, 30.45% respectively. The horizontal relapse rate of plate/screw group is 20.67%, 23.37%, respectively and vertical relapse rate is 17.93%, 21.88% respectively. There were no statistical difference in horizontal relapse rate, but were that in vertical relapse rate(p<0.01). 3. In advanced with reduction groups, the horizontal relapse rate of wire group is 20.35%, 22.75% post-OP (month, post-OP 6month respectively and vertical relapse rate is 29.72%, 32.36% respectively. The horizontal relapse rate of plate/screw group is 18.47%, 20.81% respectively and vertical relapse rate is 13.60%, 18.67% respectively. There were no statistical difference in horizontal relapse rate, but were that in vertical relapse rate(p<0.01).

수온 변화에 따른 방사무늬김(Neopyropia yezoensis) 패각 사상체의 각포자 형성량 비교

이은택,정달상,김철원,최성제,Eun Taek Lee,Dal Sang Jeong,Chul Won Kim,Sung Je Choi 국립한국농수산대학교 교육개발센터 2023 현장농업연구지 = Journal of practical agricultural resear Vol.25 No.3

This study investigated effect of water temperature change on the formation and release of conchospores of Neopyropia yezoensis. We observed that conchocelis growth and conchospores formation in oyster shell at labolatory during 7 weeks. In order to investigate the amount of conchospore formation in oyster shells, which was being cultured at 28℃, was moved to 10℃, 18℃, 28℃, and culture during 6 weeks. At 10℃, we observed an average of 127 for 1 week, 127 for 2 weeks, 95 for 3 weeks, 90 for 4 weeks, 76 for 5 weeks, and 75 for 6 weeks. At 18℃, we observed an average of 141 for 1 week, 135 for 2 weeks, 94 for 3 weeks, 153 for 4 weeks, 162 for 5 weeks, and 2 for 6 weeks. At 28℃, we observed an average of 167 for 1 week, 102 for 2 weeks, 148 for 3 weeks, 157 for 4 weeks, 270 for 5 weeks, and 138 for 6 weeks. Conchospores released from the shell grew into a young thalli in the culture for 6 weeks, and the number of ones was counted. The number of young thalli were investigated at 10℃, 0 for 1 week, 189 for 2 weeks, 200 for 3 weeks, 89 for 4 weeks, 56 for 5 weeks and 27 for 6 weeks. At 18℃, It observed 0 for 1 week, 26 for 2 weeks, 546 for 3 weeks, 16 for 4 weeks, 17 for 5 weeks and 154 for 6 weeks. It was not observed at 28℃.