SS330 용접재에서 재분포 잔류응력 및 균열닫힘영향을 고려한 파로거동에 관한 연구

이용복,정진성,조남익,Lee, Yong-Bok,Jeong, Jin-Seong,Jo, Nam-Ik 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.7

In this study residual stress in weldment was considered about the effect on the fatigue propagation and about the effect of redistribution of residual stress. Then, fatigue tests were conducted by the center notched specimens machined with welded plate. The residual stress and its redistribution after the crack growth were measured by the magnetizing stress indicator and hole-drilling method. Fatigue crack propagation was estimated by the specimens having residual stress redistributed after the cracks growth and having the effects of crack closure. Crack growth rates were predicted and compared with experimental results. It had been found that the predicted crack propagation rates have a good agreement with experimental results when the redistribution of residual stress was considerd.

압연 및 용접방향이 같은 맞대기 용접강판의 하중방향에 따른 피로균열 진전특성

이용복,김성엽,오병덕,Lee Yong-Bok,Kim Sung-Yeup,Oh Byung-Duck 대한용접접합학회 2005 대한용접·접합학회지 Vol.23 No.6

Most of the welding steel plate structures have complicated mechanical problems such as rolling directional characteristics and residual stresses caused by manufacturing process. For the enhancement of reliability and safety in those structures, therefore, a systematic investigation is required. SS400 steel plate used for common structures was selected and welded by FCAW butt-welding process for this study, and then it was studied experimently about characteristics of fatigue crack propagations with respect to rolling direction and welding residual stress of welded steel plates. When the angles between rolling direction and tensile loading direction in base material are increased, their ultimate strength not show a significant difference, but yielding strength are increased and elongations are decreased uniformly. It is also shown that fatigue crack growth rate can be increased from those results. When the angles between welding bead direction and loading direction in welded material are increase, fatigue crack growth rate of them are decreased and influenced uniformly according to the conditions of residual stress distribution. In these results, it is shown that the welded steel plate structures are needed to harmonize distributed welding residual stress, rolling direction and loading direction fur the improvement of safety and endurance in manufacture of their structures.

20세기 최대의 발견은 퀘이사와 중성자성

이용복,Lee, Yong-Bok 한국과학기술단체총연합회 1998 과학과 기술 Vol.31 No.12

훈련용 워게임 모델의 부대 DB를 분석용 워게임 모델에 재사용하기 위한 변환방법 연구 : 창조21모델과 비전21모델을 중심으로

이용복,박민형,김익현,Lee, Yong-Bok,Park, Min-Hyoung,Kim, Yeek-Hyun 한국시뮬레이션학회 2019 한국시뮬레이션학회 논문지 Vol.28 No.2

국방 M&S(Modeling&Simulation) 분야에서는 다양한 전투 환경을 동시에 모의하기 위해 다수의 워게임 모델을 연동하는 연구를 활발하게 추진하여 성과를 달성하고 있으나, 워게임 모델을 운용하기 위한 부대 DB(DataBase)는 동일한 자료임에도 불구하고 데이터의 속성(메타데이터)에 대한 표현 방법이 달라서 상호참조가 불가능한 것으로 인식되어 왔다. 이로 인해 워게임 모델을 운용하는 기관에서 같은 부대 DB를 각각 구축하기 위한 시간과 노력의 중복이 발생하고 있다. 본 연구에서는 해상도와 모의 논리는 유사하지만 도메인이 다른 훈련용 워게임 모델의 부대 DB를 분석용 워게임 모델에서 재사용하는 방법을 연구하여 실제 분야에 적용했다. 이를 위해 군단 및 사단 전투지휘훈련용 모델인 '창조21 모델'과 군단 및 사단 작전계획 모의분석용 모델인 '비전21 모델'의 부대 DB 메타데이터를 분석하여 부대 DB를 전환하는 절차를 정의하고, 부대 DB의 서로 다른 메타데이터를 매핑하는 알고리즘을 제안하였다. 본 연구는 국방 M&S 분야에서 워게임 모델 간 부대 DB의 재사용을 위해 이질적인 메타데이터를 의미상으로 통합하여 매핑을 시도한 최초 사례로서 의의가 있다. 또한, 국방 M&S 분야에서 워게임 모델 간 부대 DB의 재사용이 가능하다는 패러다임 전환과, 부대 DB 메타데이터의 표준화 필요성에 대한 시사점을 제공하였다. In the field of defense M&S, we are actively pursuing researches that interoperable multiple war game models to simulate various combat environments at the same time. Although the 'unit DB(Database)' for operating the war game models is originated from the identical data, it has been recognized that the method of expressing the attribute of the data is different and the cross reference is impossible. As a result, it makes unnecessary time and effort in establishing the same unit DB in the organizations that operate the war game model. In this study, a method of reusing the unit DB of the training war game model to the analysis war game model with similar resolution and simulated logic was applied to the actual field. For this purpose, we defined the procedure for converting the unit DB by analyzing metadata of the 'Chang-Jo21', a combat training model for corps and division, and the 'Vision21', an analysis model for corps and division operation plan. And we introduced an algorithm that can map different metadata of two unit DBs. This study was meaningful as the first attempt to map and integrate heterogeneous metadata semantically for the reuse of unit DB between different war game models in defense M&S field. Also, it provided implications for the necessity of paradigm shift that reuse of the unit DB between two different war game models is possible and the need for standardization of the unit DB metadata in the defense M&S filed.

고압 터보 펌프의 실 및 로토다이나믹스 연구

이용복,김창호,Lee, Yong-Bok,Kim, Chang-Ho 한국유체기계학회 2004 한국유체기계학회 논문집 Vol.20 No.3

시메티딘이 간혈류량에 미치는 영향 - Rat에 있어서 Indocyanine Green의 체내 동태를 중심으로 -

이용복,고익배,Lee, Yong-Bok,Koh, Ik-Bae 한국임상약학회 1993 한국임상약학회지 Vol.3 No.2

The influence of cimetidine pretreatment(100mg/kg, single i.p.) on the hepatic blood flow was investigated using pharmacokinetic parameters of indocyanine green(ICG) in the rat on the basis of hepacc perfusion-limited model. ICG(1mg/kg) was respectively administered via femoral and portal vein to the control and to the cimetidine-pretreated rats. The rate constant K12, K20 and the systemic clearance(CLt) of ICG were significantly(p<0.05) decreased ill the cimetidine-pretrea-to(B rats, but no significant diffirences were observed in hematocrit and liver weight. The biliary excretion rates of ICG were also decreased regardless of the route of administration in the cimetidine-pretreated rats. And also the hepatic blood flow in rats was decreased about $16\%$ by cimetidine. It may be concluded that the decreased hepatic blood flow with cimetidine mainly contributed to the decreased hepatic uptake and the decreased systemic clearance of ICG.

나프록센의 비선형 체내동태에 미치는 페노바르비탈의 영향

이용복,채명애,고익배 ( Yong Bok Lee,Myung Ae Chae,Ik Bae Koh ) 한국약제학회 1997 Journal of Pharmaceutical Investigation Vol.27 No.2

N/A In order to elucidate the effect of phenobarbital (PB) on the nonlinear pharmacokinetic behavior of naproxen (NAP), we compared the dose dependent hepatic intrinsic clearance, biliary excretion and protein binding of NAP in control rats to those in the PB-pretreated rats which were intraperitoneally pretreated with PB sodium (75 ㎎/㎏) once a day for four days. NAP was injected via femoral (1.5 ㎎/㎏) and portal(0.25, 0.5, 1.5, 15 and 30 ㎎/㎏) vein to the control and PB-pretreated rats, respectively. And also. we measured the plasma free fraction of NAP with the equilibrium dialysis method and the biliary excreted total amounts of NAP in both rats. Plasma free fraction of NAP was decreased in lower concentration than 150 ㎍/㎖ of NAP due to PB pretreatment. In higher concentration, however, plasma free fraction was increased. These in vitro results suggest that the total protein concentration was increased but the total binding capacity of NAP to protein was decreased by PB-pretreatment. The total plasma clearance and the hepatic intrinsic clearance of NAP had similar values in both groups, respectively. And, both clearances of NAP were significantly increased by PB-pretreatment. Even though the plasma free fractions of NAP in both groups were constantly remained within the concentration range according to the increase of administration dose, the hepatic intrinsic clearances of NAP were significantly increased in both groups with the increased dose. And, the biliary excreted total amounts of NAP were significantly increased by PB-pretreatment at the lower dose, but decreased at the higher dose. These in vivo results suggest that NAP represents the uncommon nonlinear pharmacokinetic behavior that the hepatic intrinsic clearance was enhanced with the increased dose, and that PB enhances further the hepatic intrinsic clearance of NAP with the increased dose due to its enzyme induction effect.

현대천문학의 등장

이용복,Lee, Yong-Bok 한국과학기술단체총연합회 1998 과학과 기술 Vol.31 No.11

공공기관의 입장에서본 AI

이용복,Lee, Yong-Bok 한국과학기술단체총연합회 1987 과학과 기술 Vol.20 No.11

십자형 필릿 용접부에서 재료 두께 및 용접 층수에 따른 피로파괴 특성

이용복,Lee, Yong-Bok 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.6

Most of joining processes for machine and steel structure are performed by butt and fillet welding. The mechanical properties and fatigue strength of their welding zone can be effected largely by the differential of generated heat and changes of grain size according to thickness of material and number of passes in welding process. In this study, it was investigated about characteristics of fatigue failure according to thickness of material and number of passes in cruciform fillet weld zone as the basic study for safe and economic design of welding structures. Fracture modes in cruciform fillet weld zone are classified into toe failure and root failure according to non-penetrated depth. It can be accomplished economic design of welding structures considering fatigue strength when the penetrated depth in fillet weld zone is controled properly.