• 한국압력기기공학회 논문집
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• 제8권2호
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• pp.7-13
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• 2012

A spacer grid which is one of the most important structural components in a pressurized water reactor fuel is an interconnected array of slotted grid straps, welded at the intersections to form an egg-crate structure. The spacer grid is required to not only protect fuel rods stably but also have sufficient lateral crush strength for the sake of enabling shut-down of the nuclear reactor during abnormal operating environments. Then, the lateral crush strength of the spacer grid is closely related with welding quality of the spacer grid. Previous research on the crush strength analysis of the spacer grid had been performed using only parent material properties. In this study, to investigate the effect on the crush strength of the spacer grid when used mechanical properties in weld zone instead of parent material properties, crush strength analysis considering mechanical properties in weld zone obtained from the instrumented indentation technique was performed and compared the results with the previous research.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1663-1668
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• 2012

가압경수로 핵연료의 구조부품인 지지격자체는 홈이 있는 격자 스트랩들을 끼우고, 끼워진 교차부위를 용접한 구조물이다. 원자로 비정상 운전중에 원자로의 긴급정지가 가능하도록 하기 위해 지지격 자체는 충분한 횡방향 충격강도를 갖도록 설계되어야 한다. 지지격자체의 횡방향 충격강도 해석에 대한 예전의 연구는 모재의 물성치만을 사용하여 수행되었다. 본 연구에서는 지지격자체 용접부에 모재 물성치를 사용하는 대신 용접물성치를 사용할 경우에 지지격자체 횡방향 충격강도에 미치는 영향을 조사하였다. 계장형 압입시험법으로부터 얻은 용접물성치를 용접부에 적용한 해석을 수행하였고, 그 해석 결과를 예전 연구결과와 비교하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1581-1586
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• 2009

The CEM (Crash Energy Management) concept is getting important in rail vehicle design to minimize Injury on passengers and drivers on crash event. In this paper, the accuracy of the FEA analysis result was verified through the crush test on the front part of a non-CEM based carbody. Using the verified FEA analysis method, the energy absorbing capability of the CEM based carbody was estimated.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.128-136
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• 2003

In today's design trend of vehicle structure, crush zone is fiequently reinforced by adding a box-shaped sub-frame in order to avoid an excessive deformation against a high-speed offset barrier such as EU Directive 96/97 EC, IIHS offset test. That kind of vehicle structure design results in a relatively monotonic crash pulse for airbag ECU(Electronic Control Unit) located at non-crush zone. As for an angular crash event, the measured crash signal using a single-axis accelerometer in a longitudinal direction is usually weaker than that of frontal barrier crash. Therefore, it is not so easy task to achieve a satisfactory crash discrimination performance for offset and angular crash events. In this paper, we introduce a new crash discrimination algorithm using an electronic X-Y 2-axis accelerometer in order to improve crash discrimination performance especially for those crash events. The proposed method uses a crash signal in lateral direction(Y-axis) as well as in longitudinal direction(X-axis). A crash severity measure obtained from Y-axis acceleration is used to improve the discrimination between fire and no-fire events. The result obtained by the proposed measure is logically ORed with an existing algorithm block using X-axis crash signal. Simulation and pulse injection test have been conducted to verify the performance of proposed algorithm by using real crash data of a 2,000cc passenger vehicle.

• Archives of Reconstructive Microsurgery
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• 제15권1호
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• pp.10-16
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• 2006

We retrospectively evaluated our results of replantations of distal digital amputations and analyzed the factors deterrent to the survival of replanted digits. From January 2004 to 2005 June, we performed 101 cases of replantations following complete amputations at or distal to interphalangeal joint level. The study included 98 patients with a mean age of 35.6 years (range 1 to 63 years). Amputation level correlated to zone I (distal to the lunula)in 47 cases and zone II (lunula to distal interphalangeal joint) in 54 cases according to Yamano's classification. According to the mechanism of amputation, 24 cases (22.9%) suffered from guillotine type injury, 27 cases (27.1 %) from avulsion type injury and 50 cases (50%) from crush type injury. In all cases, a single arterial anastomosis was performed. Venous anastomosis on either volar or dorsal side was performed in 12 cases of amputation in zone II. Salvage procedure for venous drainage was performed in 98 cases. The mean duration of salvage procedures was 5.9 days (ranging from 4 to 14 days). Successful replantation was achieved in 96 cases (95.1%), which included 93.7% cases in zone I amputations and 96.3% cases in zone II amputations. A single venous anastomosis was performed in 12 cases of amputation in zone II. All of them survived completely. Among the 5 cases that failed to survive, 3 cases were related with avulsion injury in zone I. Initial mechanism of injury determines the survival rate of amputated parts as it is directly related with the status of vessels and soft tissues. Meticulous precaution during the salvage procedure may affect the overall survival rate of distal digital replantations.

• 한국지구과학회지
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• 제22권6호
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• pp.548-557
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• 2001

충남 예산지구 활석광상지역에는 선캄브리아기의 유구편마암을 관입하고 쥬라기 흑운모화강암과 백악기의 산성 및 염기성 암맥의 관입을 받은 시대미상의 초염기성암체가 있다. 이 초염기성암체는 주로 사문암이고, 소량의 각섬암과 주로 사문암으로부터 형성된 활석광체를 포함한다. 이 사문암들은 사문석 반정과 layering의 발달정도에 따라 S1 ${\sim}$ S5의 5개 암석단위로 구분된다. 그러나 이들의 구성광물 및 화학조성들이 유사한 것으로 보아 사문암의 기원암은 동일마그마 기원의 감람암(dunite와 pyroxene peridotite)으로 해석된다. 사문암의 기원암인 감람암은 유구편마암이 받은 각섬암상의 광역변성작용시에 사문석화작용을 받아 사문암으로 되었고, 이 사문암으로부터의 주 활석화작용은 파쇄대를 따라 상승한 열수에 의한 열수변질작용으로 해석된다.

• 한국철도학회논문집
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• 제2권1호
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• pp.16-27
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• 1999

The purpose of this study is to suggest the effective analytical procedure using finite element model for the crashworthiness of motorized trailer of high speed train. The static crush of rectangular section frame is analyzed by experiment and numerical simulation. The equivalent thickness distribution of the aluminum frame ensuring the same energy absorption as the steel frame is obtained. In the analysis of end-on collision of TGV-K, deformed pattern and section forces are obtained, and the effect of crushable zone are examined. The numerical results are applied to the design of motorized trailer of Korean high speed train.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2040-2045
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• 2008

The priority of Crashworthiness concept for rolling stock is progressively increasing to reduce the damage of drivers and passengers as well as the car. For the first step of this research, the analysis of the crash elements have been performed. Also the longitudinal collapse force and mode is important point for whole carbody structure to guarantee the lower force at end part rather than the main passenger area. The carbody quasi-static collapse analysis and real test has been performed in the research. The crash elements FEA and test has been performed as well. After the initial Analysis and test, the correlation analysis between the FEA and test has been performed by FEA tunning. All this result will be used for real crashworthiness design for carbody structure.

• 에너지공학
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• 제14권2호
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• pp.153-158
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• 2005

본 연구에서는 폴리에틸렌 배관 전기융착부 단기성능 평가를 위한 비파괴검사를 실시할 경우 발견되는 결함에 대한 판정기준을 개발하였다. 인위적으로 $3.8mm\~25mm$ 내에서 6가지 크기의 결함을 삽입한 시험 편을 설계 및 제작하여 기계적 평가를 실시하고 또 이론적 해석을 하였다. 안전계수 2를 적용하여 유효 응력을 산정할 경우 최대 허용 가능한 결함 크기는 11 mm(열선 폭의 $30\%$)이며 안전 계수를 4를 적용할 경우에 최대 허용 가능한 결함 크기는 3.8mm(열선 폭의 $10\%$)이다.

• 터널과지하공간
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• 제29권6호
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• pp.508-522
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• 2019

비탈면의 붕괴로 인해 재산피해뿐만 아니라 인명피해 또한 발생할 수 있으므로 안정성 평가를 통해 비탈면의 붕괴여부 예측 및 보강을 진행해야 한다. 본 논문은 비탈면 영상에서 암반 절리군, 암반 단층, 토양, 비탈면 누수영역 등 비탈면 붕괴와 관련하여 특성화 시킬 수 있는 지반 영역들을 정의하고 이를 딥러닝 기법을 통해 자동으로 분류해 낼 수 있는 방법에 대해 고찰하였다. 이에 따라 딥러닝 객체 영역분할(Instance segmentation) 네트워크를 활용하여 영상에 보여지는 다른 특성을 갖는 지반영역의 정확한 형상을 인식하고 자동 분할 할 수 있음을 보였으며, 향후 비탈면 안정성 평가를 위해 시행되는 비탈면 매핑 작업을 지원하고, 비탈면 보강 대책 등 의사결정에 필요한 비탈면의 지반특성 정보를 자동으로 산출할 수 있는 가능성을 보였다.