• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.741-746
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• 1995

일체형원자로는 노심, 증기발생기, 가압기, 펌프 등 1차측 주기기들을 하나의 압력용기 안에 모두 포함하고 있고 또 1차측 냉각재가 원자로 안에서만 순환하므로 기존의 분리 형에 비해 구조특성상 상당히 다른 설계개념이 필요하다. 본 연구에서 개발중에 있는 일체형 열병합원자로에서 채택한 설계개념은, 먼저 증기발생기는 많은 수의 전열관들이 나사선처럼 노심지지원통을 감고 올라가는 일체형 관류식 나선형을 사용하였으며, CEDM은 지진하중과 같은 동적하중에 의한 영향을 최소화하기 위하여 원자로용기 외부로의 돌출부분을 최소화하는 설계개념을 채택하였다. 또한 가압기는 별도의 부품없이 원자로용기 헤드의 빈공간을 활용한 자기가압방식으로 대체하였고 냉각재 펑프는 Canned Motor Pump를 원자로벽에 직접 부착하는 개념을 사용하였다. 본 논문에서는 예비개념설계된 일체형 신형원자로의 기계구조설계상의 특징들을 설명하고 앞으로의 연구방향을 간략히 소개한다.

• Land and Housing Review
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• v.12 no.3
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• pp.97-108
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• 2021

In bridge abutment structures, lateral squeeze due to lateral stress of embankment placement and thermal movement of the bridge structure leads to failure of approach slabs, girders, and bridge bearings. Recently, GRS (Geosynthetic-Reinforced Soil) integral bridge has been proposed as a new countermeasure. The GRS integral bridge is a combining structure of a GRS retaining wall and an integral abutment bridge. In this study, numerical analyses which considered construction sequences and earthquake loading conditions are performed to compare the behaviors of conventional PSC (Pre-Stressed Concrete) girder bridge, traditional GRS integral bridge structure and GRS integral bridge with bracket structures (newly developed LH-type GRS integral bridge). The analysis results show that the GRS integral bridge with bracket structures is most stable compared with the others in an aspect of stress concentration and deformation on foundation ground including differential settlements between abutment and backfill. Furthermore, the GRS integral bridge with/without bracket structures was found to show the best performance in terms of seismic stability.

• Composites Research
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• v.33 no.3
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• pp.147-152
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• 2020

In this study, void behavior of composite laminate by local internal pressure gradient due to structural geometry and surface film application condition was experimentally evaluated through fabrication of spar/skin integrated structure specimens. Viscosity comparison and thermal analysis for both carbon fiber prepreg and surface film were conducted and cure characteristic and rate difference were analyzed. 2 types of spar/skin integrated structural specimens were prepared based on different application condition of surface film. Subsequently, those specimens were evaluated through visual surface inspection, non-destructive and destructive inspection. In a specimen #1 with full application of surface film, low pressurized area of composite laminate created by pressure gradient of structural geometry had voids. It exhibited that voids could not be evacuated and were locked in cured laminate by the influence of pre-cured surface film with relatively faster cure rate. In a specimen #2 without surface film, it revealed that all internal voids disappeared in the cured laminate. Therefore, it is verified that surface film acts as barrier film preventing void movement and evacuation during autoclave cure.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.116.1-116.1
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• 2005

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.70-78
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• 2018

This research was carried out to develop an integrated folding wing made from carbon composite materials. Design requirements were reviewed and composite wing sizing was conducted using design optimization with commercial software. Three composite manufacturing processes including hot-press, pultrusion, and autoclave were evaluated and the most suitable processes for the integrated wing fabrication were selected, with consideration given to performance and cost. The determined manufacturing process was verified by two design development tests for selecting the design concept. Stiffness and strength of the composite wing were estimated through structural analyses. The test loads were calculated and static tests about design limit load and design ultimate load were performed using both wings. As a result, the evaluation criterions of the tests were satisfied and structural safety was verified through the series of structural analyses and testing.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.5
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• pp.455-468
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• 2013

In recent, various types of steel pipe-roof methods, which is reinforced by mortar after propulsion of steel pipe into the ground, have been used for the construction of trenchless underpass. Integrated steel pipe-roof has flexural stiffness and can resist against overburden load and reduce the stress acting on the concrete underpass structures. Due to arching effect, vertical and horizontal stress distribution around the steel pipe-roof is changing. In this study, therefore, the characteristic of stress distribution around the underpass induced by the construction of integrated steel pipe-roof is investigated by using numerical method. To examine the soil-structure interaction, interface element is introduced. Results show that vertical stress acting on the concrete structure placing inside the steel pipe-roof is significantly reduced due to arching effect and flexural stiffness of integrated steel pipe-roof. Design load can be reduced and effective design of underpass will be available if the earth pressure reduction due to arching effect is considered in the design stage.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06a
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• pp.54-64
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• 1995

대표적인 대형 베어링인 일체형 볼 베어링과 와기어 레이스형 볼 또는 로울러 베어링의 마찰 특성을 비성형 유한요소 프로그램인 MARC를 사용하여 상호간의 마찰형상에 대한 접촉응력과 마찰력 특성을 비교 해석하였다. 특히 와이어 레이스식 슬루잉 링 베어링은 우수한 마찰특성 때문에 건설기계, 하역기계, 광산기계나 탱크와 같은 국방무기 등에서 널리 사용되고 있다. 접촉면의 변형에 따른 일체형의 볼 베어링은 마찰력과 기울기면에서 와이어 레이스식 베어링에 비하여 크고, 같은 와이어 레이스식 베어링에서는 마찰력의 경우 볼 타입이 로울러 탕입에 비하여 약간 크게 나타났다. 이들의 계산결과를 종합하면 와이어 레이스식 베어링이 일체형 베어링에 비하여 마찰특성이 우수하고, 특히 와이어 레이스 베어링중에서 로울러 타입은 마찰 토오크면에서 균일하기 때문에 베어링을 사용한 제어기능 설계에서 특히 우수한 결과를 제공할 수 있다. 유한요소 해석결과는 기존의 실험결과와 잘 일치하고 있어서 슬루잉 링 베어링의 최적설계에 유한요소 해석의 유용함을 확인하였다. 또한 상부 구조물과 하부 구조물을 연결하기 위한 체결볼트의 구멍은 하중조건에 따라서 구조적 불안정성을 야기할 수 있음도 확인하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.2
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• pp.127-133
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• 2013

In this paper, the study for the manufacture of the integrated composite wing is performed. The wing has a pivoting structure and high aspect ratio to increase lift drag ratio. The wing is designed with carbon fiber composite because the wing needs to be light and have sufficient strength and stiffness to satisfy structural design requirements. The number of structural members is decreased by part integration to reduce manufacturing cost and the wing is manufactured with the integrated molding process by an autoclave. The material properties are identified by the coupon tests and the structural strength and stiffness are verified through the component tests.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.276-282
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• 1996

일체형원자로는 노심, 증기발생기, 가압기, 펌프 등 1차측 주기기들을 하나의 압력용기안에 모두 포함하고 있고, 또 1차측 냉각재가 원자로 안에서만 순환하므로 기존의 분리형원자로에 비해 구조특성상 대용량 원자로 냉각재 상실사고(LBLOCA)의 발생 가능성을 원천적으로 제거할 수 있다. 반면 원자로 냉각재의 보충 등을 위한 소형 배관의 파단 가능성은 역시 존재하므로 소용량 원자로 냉각재 상실 사고(SBLOCA)는 여전히 존재한다. 따라서 현재 한국원자력연구소에서 연구 개발중인 중소규모 전력생산 및 열 활용 목적의 일체형 원자로에는, 원자로 압력용기 외부에 별도의 압력용기(안전용기)를 설치하여 SBLOCA시 원자로 압력용기로부터 방출되는 냉각수를 안전 용기내에 보관하도록 함으로써 사고시 외부로의 방사성 물질 유출 가능성을 획기적으로 줄 일수 있는 설계 개념을 도입하고 있다. 본 논문에서는 안전용기의 설계시 효율적인 냉각방식에 대한 열유체 해석적 접근을 시도하였고, 예비개념설계된 일체형 열병합원자로의 설계상의 특징들 및 안전용기 설계시 앞으로의 연구방향 등도 간략히 소개하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.220-228
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• 2010

A steel wire-integrated deck plate that welds integrated triangle truss steel wires on a galvanized steel sheet is developed to reduce construction costs of a slab or formwork such as shores and supports, and it is already widely applied in many construction fields. This study selected upper and lower steel wires, lattice steel wires, span, and cutting methods of ends as variables, and conducted an experimental test by manufacturing a total of 32 full scale test bodies. According to the result, changes in final destruction types of the test bodies and cutting methods of ends didn't affect structural performance of test bodies, and for a 3.2m-span test body, there was no big problems in using ${\Phi}4.5$ of lattice steel wires.