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볼트이음방식의 블록전단파괴에 미치는 영향에 대한 실험적 연구
이진옥(Lee, Chin-Ok),박경현(Park, Gyung-Hyeon),문지호(Moon, Jiho),이학은(Lee, Hak-Eun),임남형(Lim, Nam-Hyoung) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.11
블록전단파괴는 인장부재의 한계상태에 해당하는 것으로 강구조물의 인장부재 또는 연결부 설계 시 주의를 요한다. 많은 연구 결과와 설계기준에서는 블록전단파괴에 대한 볼트 이음 방식의 영향을 고려하지 않고 있다. 본 연구에서는 볼트 이음 방식(지압이음과 마찰이음)이 블록전단파괴의 파괴모드와 파괴강도에 미치는 영향을 분석하고 자 인장실험을 실시하였다. 실험결과의 분석으로부터 설계기준, 지압이음, 마찰이음에 따른 파괴모드의 차이를 제시 하였으며 마찰이음에서 발생되는 마찰력으로 인한 블록전단파괴강도의 변화를 고찰하였다. Block shear failure is one of limit states, and demands great caution in designing the tension member or connection joint of steel structures. From many studies and design specification, it is shown that the effect of the bolted connection type on the block shear failure was not considered. In order to investigate the effect of the bolted connection type(bearing type connection and slip critical connection) on the mode/strength of the block shear failure, tensile experiment is conducted in this study. Differences about the failure mode according to the design specification, bearing type connection, and slip critical connection are proposed from the analysis of test results. The variation of the block shear failure strength due to the frictional force in the slip critical connection is also investigated.
이진옥(Chin Ok Lee),이학은(Hak Eun Lee),유철수(Chul Soo Yu) 한국강구조학회 1993 韓國鋼構造學會誌 Vol.5 No.2
An elasto-plastic response was studied for economical and rational seismic design of arch bridge. Only elastic design for earthquake of small probability could cause noneconomical results. Considering the fact that basic concept of seismic design permits damages of bridge and requires sustaining of essential function after earthquake, the elasto-plastic seismic analysis of arch bridge contributes to the more economical seismic design and examination of stability for seismic loading. In the case of the steel deck type arch bridge subjected to strong earthquake, columns are first yielded into plastic deformation and showed fragility for the seismic loading and the generation of plastic hinge was found each time step. The present study enables to estimate of failure mode of bridge structure subjected to strong earthquake.
임남형,최상현,이진옥,성익현,Lim, Nam Hyoung,Choi, Sang Hyun,Lee, Chin Ok,Sung, Ik Hyun 한국강구조학회 2005 韓國鋼構造學會 論文集 Vol.17 No.5
During summer, very high compressive force occurs on the continuous welded rail (CWR) track because of the increase of rail temperature (max. $60^{\circ}C$). This extreme temperature stress can cause the CWR track to buckle. Among many CWR parameters affecting the track buckling, the influence of the lateral and longitudinal ballast resistance was investigated on the stability of the CWR track in this study. Also, the sensitivity of the track irregularity such as the alignment defect and the gauge irregularity was investigated. 혹서기에 레일의 높은 온도 상승(최대 $60^{\circ}C$)으로 인해 장대레일 궤도에는 매우 큰 압축력이 작용하게 된다. 이러한 압축력은 장대레일 궤도의 좌굴을 발생시키기도 한다. 본 연구에서는 장대레일 궤도의 좌굴에 영향을 미치는 많은 요소들 중에서 도상 횡저항력 그리고 도상 종저항력이 궤도 좌굴에 미치는 영향을 파악하기 위한 연구를 수행하였다. 또한 줄틀림과 궤간틀림의 민감도를 분석하였다.
기니픽 심근의 수축력과 세포내 $Na^+$ 활성도에 미치는 ${\alpha}_1-Adrenergic$ 수용체 자극효과
김진상,강형섭,채수완,이진옥,Kim, Jin-Sang,Kang, Hyung-Sub,Chae, Soo-Wan,Lee, Chin-Ok 대한약리학회 1996 대한약리학잡지 Vol.32 No.2
Myocardial ${\alpha}_1-adrenoceptors$ have been shown to mediate a biphaslc inotropic response that was characterized by a transient decline followed by a sustained increasing phase in guinea pig ventricular muscle. Recently one group reported that an ${\alpha}_1-adrenoceptors-induced$ intracellular $Na^+$ decrease is linked to fast $Na^+$ channel inhibition and another group reported that it is linked to $Na^+$-$K^+$ pump activation by ${\alpha}_{1b}-adrenoceptors$. But until now, its mechanism is not clear. Therefore, to see whether the $Na^+$channel or $Na^+-K^+$ pump is related to a decrease in intracellular $Na^+$ activity and/or the negative inotropic response, and which ${\alpha}_1-adrenoceptor$ subtype was involved in the decrease in intracellular $Na^+$activity by phenylephrine, we used conventional and sodium selective microelectrodes, and tension transducer to determine the effects of ${\alpha}_1-adrenergic$ stimulation on membrane potential, intracellular $Na^+$ activity, and twitch force in guinea pig ventricular muscles. $10^{-5}$ M Phenylephrine produced a slight hyperpolarization of the diastolic membrane potential, a decrease or increase in $a_N^i_a$, and a biphasic inotropic response. The negative inotropic response accompanied by a decrease in intracellular $Na^+$activity, whereas in muscles showing a remarkable positive inotropic response without initial negative inotropic effect was accompanied by an increase in intracellular $Na^+$ activity. The decrease in intracellular $Na^+$ activity was apparently inhibited by WB4101, an antagonist of the ${\alpha}_{1a}-adrenoceptors$. The decrease in intracellular $Na^+$ activity caused by phenylephrine was not abolished or reduced by a block of the fast $Na^+$ channels. $V_{max}$ also was not affected by phenylephrine. Phenylephrine produced an increase in intracellular $Na^+$ activity in the presence of a high concentration of extracellular $Ca^{2+}$ (in quiescent muscle) or phorbol dibutyrate, a protein kinase C activator(in beating muscle). These suggest that the ${\alpha}_{1a}-adrenoceptors-mediated$ decrease in intracellular $Na^+$ activity may be related to the protein kinase C.
SS275 강재의 응력 평가를 위한 바크하우젠 잡음 특성
김종민(Kim, Jong-Min),이진옥(Lee, Chin-Ok),임남형(Lim, Nam-Hyoung) 한국방재학회 2022 한국방재학회논문집 Vol.22 No.2
전자기 바크하우젠 잡음(MBN)은 강자성 재료의 피로, 크리프, 응력 및 경도를 감지하는 데 잠재적인 능력이 있다. 최근 국내에서 철도 레일의 잔류응력을 측정하기 위하여 전자기 바크하우젠 잡음을 이용한 비파괴 장비(센서와 데이터수집장치, 데이터분석프로그램)가 개발되었다. 이러한 MBN은 강자성체인 강재의 종류와 잔류응력에 따라 다른 특성을 가지고 있다. 본 연구에서는 개발된 MBN 장비를 사용하여 SS275강재의 응력 변화에 따른 MBN 신호의 특성을 실험적으로 분석하였다. 본 연구의 결과는 향후 SS275 강재의 잔류응력 추정을 위한 기본 자료로 활용될 수 있다. Magnetic Barkhausen noise (MBN) can be used to potentially detect fatigue, creep, stress, and hardness in ferromagnetic materials. Recently, non-destructive measurement equipment using MBN has been developed to measure the residual stress of railway rails in Korea. MBN has different characteristics depending on the type of ferromagnetic steel and residual stress. In this study, MBN signal characteristics based on the stress change of SS275 steel are experimentally analyzed using the developed MBN equipment. The results of this study can be used as basic data for estimating the residual stress of SS275 steel in the future.