• 드라이브 ㆍ 컨트롤
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• 제18권2호
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• pp.32-37
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• 2021

The piston reservoir is mainly used in hydraulic blow-down system for aerospace engineering. The reservoir is heavy due to both hydraulic cylinder and piston in pressurization. The positive expulsion tank with rubber diaphragm has been mostly applied propellant and fuel tank at low pressure to satellites. To reduce weight, the reservoir that can be used at high pressure with rubber diaphragm was developed. In this research, the prediction of life-time for the rubber diaphragm was implemented through an accelerated life test, as a part of development of new reservoir. Also, the diaphragm was stored in an temperature chamber at the same condition as and operation with hydraulic oil. As a result, the life-time for a rubber diaphragm was successfully evaluated via Arrhenius law and Time-Temperature Superposition based on failure times over temperatures in the accelerated test.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3221-3223
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• 2007

Recently, nuclear power plant companies have been extending the turbine valve test interval to reduce the potential of the reactor trip accompanied with a turbine valve test and to improve the NPP's economy through the reduction of unexpected plant trip or decreased operation. In these regards, the extension of the test interval for turbine valves was reviewed in detail. The effect on the destructive overspeed probability due to the test interval change of turbine valves is evaluated by Fault Tree Analysis(FTA) method. Even though the test interval of turbine valves is changed from 1 month to 3 months, the analysis result shows that the reliability of turbine over speed protection system meets acceptance criteria of 1.0E-4/yr. This result will be used as the technical basis on the extension of the test interval for turbine valves. In this paper, the propriety of the turbine valve test interval extension is explained through the review on the turbine valve test interval status of turbine overspeed protection system, the analysis on the annual turbine missile frequency and the probability evaluation of the destructive overspeed due to the test interval extension.

• Strategy21
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• 통권39호
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• pp.114-139
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• 2016

Korea and China are neighboring countries with close contacts in many areas from long time ago, and have shared interests in maintaining peace and stability on the Korean Peninsula, and in deepening economic relationship which has been mutually complementary in their nature. Therefore their bilateral relations has been developed at a remarkable pace to the extent that it can't be better than now. However, the differences in their responses to North Korean nuclear test and ensuing long-range ballistic missile test-fire and the Chinese strong concern on the possible deployment of THAAD (Terminal High Altitude Air Defence) anti-missile system in Korea show that there are some weaknesses in their relations. For example, Korea is not still confident that China would fully implement the sanction measures contained in the UNSC resolution and I argue that Chinese proposal of parallel negotiation of the denuclearization and the replacement of Korean armistice with the Peace Agreement is not much persuasive. In THAAD issue, if Korea comes to conclusion in the future that THAAD is the most effective way to counter North Korean threats, Korea should make every efforts to assure China that Korea-US alliance is not targeting China, and the THAAD is a defensive system, not damaging Chinese security. In the longer-term, deepening strategic distrust and competition between the US and China in this part of East Asia, changing nature of economic cooperation between Korea and China, and the revival of 'great country mentality' by Chinese people together with the rising nationalism in both Korea and China would cast shadow on Korea-China relation in the years ahead, unless properly handled. In this regard, I suggest that the security communications between the two countries be further strengthened, and the tri-lateral dialogue channel be established among the three countries of Korea, the US and China, particularly on North Korean issues. I also suggest the new pattern of economic cooperation be sought, considering the changing economic environment in China, while strengthening the efforts to understand each other through more interactions between the two peoples.

• 한국전산구조공학회논문집
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• 제32권5호
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• pp.333-340
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• 2019

모듈형 LNG Tank의 외조를 구성하는 SCP(sandwich concrete panel)에 대해서 중속충돌시험기로 충돌시험을 수행하고 이에 대한 수치해석을 수행하였다. 충돌시험에 사용된 시험체는 가로세로 각각 2m로 외조의 일반단면과 연결부단면의 특성을 가지도록 제작하였다. 51kg의 탄자를 설계기준에 규정된 충돌에너지를 갖도록 중속충돌시험기로 45m/sec로 이상의 속도로 가속하여 충돌시켰다. 이런 충돌시험을 두 차례 반복하고 시험체의 극한능력을 평가하기 위하여 충돌속도를 2배로 하여 충돌시켰다. 충돌시험의 수치해석 모델은 LS-DYNA를 이용하여 수행되었다. 외측의 강판와 그 사이의 충진콘크리트를 고체요소로 모델링하고 전단연결재는 보요소를 이용하여 모델링하였다. 강재의 재료모델은 탄소성 및 파단거동을 고려하였으며 콘크리트의 재료는 CSCM재료로 모델링하였다. 해석에서 전면부의 충돌변형은 시험에서 얻어진 변형과 유사한 값을 얻었으나 후면부의 변형은 시험결과와 다소 작은 값을 보였다. 일반부 단면에 대한 2배속 충돌시험에서는 전후면의 강판이 파손되었으나 해석결과에서는 전면부의 강판만 파손되었다. 수치해석에서 충돌에너지는 주로 충진 콘크리트로 전이되었는데 이는 이전 연구에서 보였던 고에너지를 가진 충돌의 경우와 다른 경향이다. 작성된 모델은 구조적으로 보수적인 결과를 보이므로 실제 설계에 적용할 수 있을 것으로 판단된다.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.405-413
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• 2011

Defense Systems Test Center in ADD supports increasingly various missile test requirements such as higher altitude event, multi target operation and low-altitude, high velocity target tracking. In this paper, we have proposed the development of instrumentation radar tracking status simulator based on virtual reality. This simulator can predict the tracking status and risk of failure using several modeling algorithms. It consists of target model, radar model, environment model and several algorithms includes the multipath interference effects. Simulation results show that the predict tracking status and signal are similar to the test results of the live flight test. This simulator predicts and analyze all of the status and critical parameters such as the optimal site location, servo response, optimal flight trajectory, LOS(Line of Sight). This simulator provides the mission plan with a powerful M&S tool to rehearse and analyze instrumentation tracking radar measurement plan for live flight test at DSTC(Defense Systems Test Center).

• 한국항공우주학회지
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• 제35권1호
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• pp.73-78
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• 2007

국내 개발에 성공한 기본훈련기(KTX-1) 시제기 및 외부연료탱크를 활용하여 유도무기에 적용되는 핵심 부품의 비행환경 성능을 검증할 수 있는 탑재비행시험(Captive Flight Test) 절차 및 결과를 소개한다. 2001년부터 2006년까지 총 150 쏘티 이상의 탑재비행시험을 통하여 국내 개발된 탐색기, 항법장치/기법, 관성센서, 전파고도계 등을 비행환경에서 시험평가하여 유도무기체계 연구개발 단계에서 일정단축 및 비용절감에 기여하였다.

• 항공우주정책ㆍ법학회지
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• 제22권1호
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• pp.55-74
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• 2007

When the People's Republic of China destroyed one of its own defunct meteorological satellites, the Fengyun-1C, at an altitude of some 865 km above the earth's surface, the PRC was accused of initiating, or at the very least risking an(other) arms race in outer space also. The test also gave rise to a few legal questions as to the permissibility of this test, and the broader permissibility of using space for military and other weapon-touting activities, Whilst the test cannot be considered to constitute a direct threat to international peace and security so as to invoke relevant legal principles and consequences in terms of the UN Charter for example, it highlights the importance of such clauses in international space law as requiring international cooperation and consultation, due regard for the interests of all other countries both on earth and in outer space, and the further development of general regimes of registration and space debris-prevention. From that perspective, the PRC violated international outer space law not so much by the test itself but by the accompanying lack of information, consultation and due regard for other states', and indeed mankind's, interests.

• 항공우주정책ㆍ법학회지
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• 제spc호
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• pp.181-199
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• 2007

When the People's Republic of China destroyed one of its own defunct meteorological satellites, the Fengyun-1C, at an altitude of some 865 km above the earth's surface, the PRC was accused of initiating, or at the very least risking an(other) arms race in outer space also. The test also gave rise to a few legal questions as to the permissibility of this test, and the broader permissibility of using space for military and other weapon-touting activities, Whilst the test cannot be considered to constitute a direct threat to international peace and security so as to invoke relevant legal principles and consequences in terms of the UN Charter for example, it highlights the importance of such clauses in international space law as requiring international cooperation and consultation, due regard for the interests of all other countries both on earth and in outer space, and the further development of general regimes of registration and space debris-prevention. From that perspective, the PRC violated international outer space law not so much by the test itself but by the accompanying lack of information, consultation and due regard for other states', and indeed mankind's, interests.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1132-1139
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• 2006

Non-contact underwater explosions against surface ship could cause extensive equipment damage during wartime service. Thus, the need to develop methods for the design of shock resistant equipment structures and systems was strongly established. In analytical methods, DDAM(Dynamic Design and Analysis Method) and transient repsonse method are used for ship shock design. In this paper, to analyze the characteristics of DDAM, medium weight shock test, DDAM and transient response analysis for missile system equipment are performed.

• 한국군사과학기술학회지
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• 제10권4호
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• pp.125-131
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• 2007

This paper considers the mechanical properties test results of the ceramic fiber reinforced plastic using hyper temperature. These materials were developed to make antenna cover which should not only protect antenna from high temperature and high pressure but also transmit and receive radio frequency for hypersonic missile. So the bending strength tests under the room temperature and the hyper temperature for new materials were done to evaluate of their performances. Also, the conductivity, specific heat, diffusivity and density were tested.