• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.156-159
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• 2000

경량소재로 사용되는 polyurethane은 난연화 및 강도유지를 위해 난연제, 섬유 및 무기충진제 등을 첨가하거나 고밀도화하여 사용하며 발포시켜 경량화하여 성형된다. Polyurethane 발포체는 자동차 내장재, 건축 구조재, 건축 내외장재, 가구재, 포장재료, 신발, 의류 제품, 단열재 등 다양하게 사용되고 있다. 이러한 polyurethane 발포체는 제조 및 가공의 편리함에 비해 화재발생시 연기발생량이 많고 연소가 용이하여 화재를 전파하는 매개물의 역할을 하여 피해를 더욱 가중시키는 취약점을 가지고 있다. (중략)

• Review of KIISC
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• v.32 no.5
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• pp.45-51
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• 2022

소프트웨어의 개발에서 오픈소스 소프트웨어(Open Source Software, 이하 OSS)의 사용이 급증하고있다. 이애에 많은 OSS의 재사용 및 OSS간 재사용으로 인하여 OSS의 신규 취약점 대응 및 관리가 어려워지고 있다. 따라서 본 논문에서는 인공지능을 이용하여 OSS 프로젝트의 구조적 정보를 활용하여 여러 가지 OSS 재사용 기법에 대응하는 개선된 OSS 재사용 탐지(OSS Cloning Detection, OCD) 기술을 제안하고 그 성능을 평가한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.231-238
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• 2003

Reinforced concrete buildings damaged by earthquake which can be reused can ensure the stability in its structure by repair-restrengthening, but when such a repair-restrengthening is conducted inappropriately or its structural strength is greatly reduced by earthquake again, it should have repair-restrengthening. This study selects beam-column joints which are vulnerable to earthquake as the object of experiment, performs repair-restrengthening after applying the first and the second dynamic loading to the objects of experiment, examines the capacity of restrengthening according to structural characteristics and loading velocity and verifys the validity of repair-restrengthening.

• Composites Research
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• v.16 no.3
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• pp.49-57
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• 2003

This paper presents the tensile characteristics for carbon/epoxy, carbon/phenolic and silica/phenolic composites under elevated temperature, which are considered for vehicle structure or thermal protection materials. The tensile test was conducted with servo-hydraulic testing machine and high temperature furnace, and the mechanical properties such as tensile strength, elastic modulus and Poisson's ratio were evaluated by using high temperature strain gages. Also, they were compared each other with respect to fiber orientation and temperature effect. These test results were used for designing and analyzing some airframe structures with these composites.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.833-839
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• 2013

In this study, an experiment was performed to monitor the two-dimensional shape of a cantilever composite structure using fiber Bragg grating (FBG) sensors. To monitor the shape of a composite structure, a deflection equation developed by NASA was applied and a composite beam attached to three FBG sensors was used. In the experiment, the shape of the composite beam was successfully estimated and an error was evaluated by comparing a real deflection. The error increased with real deflection; therefore, it was compensated by using the linear relationship between the error and the real deflection. After compensating the error, the measured deflection shows good agreement with the real deflection. Finally, the experiment shows that the FBG sensor and the deflection equation are suitable for monitoring the deflection curve of the beam structure with compensation of the error.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.255-255
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• 2015

국제핵융합실험로(ITER)의 3대 목표 중 하나는 핵융합로 개발을 위한 삼중수소증식블랑켓 개념을 시험하고 검증하는 것이며, 이를 위해 시험증식블랑켓(TBM, Test Blanket Module) 프로그램을 마련, 각국이 참여할 수 있도록 하고 있다. 한국도 2012년 국가핵융합위원회 결정에 따라, EU, 일본, 중국, 인도와 함께 TBM 프로그램에 참여하고 있으며, 2021년 설치를 목표로 헬륨냉각 고체증식재 개념의 HCCR (Helilum Cooled Ceramic Reflector) TBM을 설계, 개발하고 있다. 한국형 TBM은 총 4개의 서브모듈과 하나의 후벽(Back Manifold, BM) 으로 구성되며, 각 서브모듈은 플라즈마와 대면하는 일차벽(First Wall, FW), 증식재와 증배재, 반사재를 담고 있는 증식영역(Breeding Zong, BZ), 냉각재 매니폴드 및 구조물 역할을 하는 측벽(Side Wall, SW) 등의 기능부품으로 구성되어 있다. 냉각재는 8 MPa, $300-500^{\circ}C$의 고온고압헬륨을 사용하고, Li2SiO4 혹은 Li2TiO4 형태의 Li 세라믹 증식재를 사용하며, 중성자 증배를 위해 Be 증배재 및 흑연 반사재를 사용한다 [1-3]. 2015년 2월 개념설계검토(CDR, Conceptual Design Review)를 위해, TBM-shield를 포함한 TBM-set 설계가 완료되었으며, 열수력, 구조, 지진, 전자기, 복합하중에 대한 평가가 진행되었다. 본 논문에서는 이 중 H/He-phase에 시험될 EM-TBM과 D-T phase에 시험될 INT-TBM에 대한 열수력 성능 결과를 소개하였다[5]. 각각의 열부하 조건은 0.17과 $0.3MW/m^2$이며, 중성자 조사는 D-T phase 에서만 고려되었다. 구조재 및 사용된 기능소재별 온도 요건을 정의하고, 성능해석 결과와 비교하였으며, 이를 통해 모든 온도 요건을 만족함을 최종 확인하였다. 이러한 온도 분포는 열응력 평가를 위해 구조해석 입력자료로 활용되었다.

• Composites Research
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• v.25 no.2
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• pp.46-53
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• 2012

Using pultrusion process, FRP composite structural members having various cross-section shapes can be produced with unlimited lengths. Because of such reasons, these members are suitable for the application in the construction field. Especially, this material is highly appreciated if the material is to be used in the corrosive environments such as aquatic or oceanic environments due to its high corrosion resistance. However, design criteria for the FRP structural member are not developed yet. So, the research on the development of design guideline is needed ungently. In order to use the pultruded structural FRP member efficiently, the members are composed of thin plate components, and thus, the member is prone to buckle easily and the buckling is one of the governing strength limit states for the design. In this paper, we present the analytical study results pertaining to the buckling behavior of I-shape FRP compression member. In addition, design procedure and flow-chart are also proposed based on the study results including previous experimental results. Proposed design procedure is similar to that in ANSI/AISC 360-10 with minor modification. Therefore, it is convinced that the structural design of pultruded FRP compression member could be done easily by following design procedure proposed in this paper.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.5
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• pp.326-332
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• 2010

Critical response of seawater pump impeller shaft structure to various exciting loads is a fundamental factor in re-designing of the structure after its functional failure. In this paper, a typical case of the shaft structure's failure is investigated for re-designing purposes. Failure causes of interest are excessive bending moment, fatigue loads and dynamic resonance due to relevant motor rotation and unbalancing of the rotation loads. Static analyses of shaft structure under the conditions of concerned loads are carried out, followed by a dynamic investigation of the effects of resonance between the shaft and the motor on the structure. The relevant structural analyses are carried out using the Finite Element Methods combined with ANSYS code. Based on these, the primary cause for the shaft's structural failure is obtained. It is found that the change of the bending stiffness of the shaft is the primary concern in the re-designing process. A guideline for the re-design process of the seawater pump shaft structure is established, and a re-design scheme of the structure is proposed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.1002-1008
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• 2001

The absorbing structure composed of multi-layered fiber reinforced composite materials was designed and microwave absorbing properties are investigated. On the basis of transmission line theory, the theoretical equations to predict the reflection loss and the appropriate composite material for each functional layer are suggested. The most significant result of this study is the successful design and fabrication of triple-layered composite laminates which has the superior microwave absorbing porperties (more than 10 dB in 4∼12 GHz range), without using the ferrite filler in the impedance transforming layer. In the two-layered composite laminate (absorber/substrate), however, the use of ferrite filler (about 40 wt %) in the absorbing layer is necessary to obtain the certain level of microwave absorbance. By combining the glass-fiber composite with ferrite filler and carbon-fiber composite substrate, the microwave absorbing properties more than 10 dB in 4∼12 GHz frequencies than be obtained.

• Composites Research
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• v.27 no.2
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• pp.77-81
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• 2014

In this study, it was performed damage assessment and repair of small scale aircraft adopted on composite. This aircraft adopted the sandwich structure to skin of wing. This study aims to investigate the residual strength of sandwich composites with nomex honeycomb core and carbon fiber face sheets after the open hole damage by the experimental investigation. The 4-point bending tests were used to find the bending strength, and the open hole was applied to introduce the simulated damage on the specimen. The bending strength test results after open hole were compared with the results of no damaged specimen test. In addition, The damaged composite structure was repaired using external patch repair method after removing damaged area. After that, this study presents comparison results of the experimental investigation between the damaged and the repaired specimen. It was found that the bending strength of repaired specimen was recovered up to 95% of undamaged specimen.