• 한국산업융합학회 논문집
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• 제4권2호
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• pp.119-125
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• 2001

This paper discuss the Qualification Test Procedure which is composed of main functional and environmental tests for the localizing avionics and subsystems, especially the detail test approaches of General Avionics Computed(GAC) through the analysis of related technical data packages for the purpose of performance proof of final products. Quality assurance procedures are properly established with the several kinds of inspections and functional test items. They are called as process inspections, functional test, acceptance test procedure and qualification test procedure. The Qualification test procedure are composed of the analysis of original engineering design concept and shall be performed for the acquisition of the certification of the GAC's quality as well as the aquisition of the related techniques and engineering know-how items.

• 한국산업융합학회 논문집
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• 제3권3호
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• pp.251-256
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• 2000

This report analyzes the Source Qualification Test which is composed of main functional and environmental tests for the localizing avionics(electronic subsystem for aircrafts and spacecraft) and high performance mechanical subsystem. Especially the detail test approaches of integrated servo actuators which is the main part to supply the power to the main and other flying control panel. Nowadays this subsystem works with mechanical and electrical engineering technique. In detail, electrical signal is used as input and transferring tool and mechanical part is the output as a power and manufacture the physical dimensions and functions. Finally in this review, the new test procedure to prove the function by the new manufacturer is established.

• 한국항공우주학회지
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• 제44권12호
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• pp.1035-1042
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• 2016

상용 비행시뮬레이션 게임 엔진 X-Plane을 이용하여 구성한 비행시뮬레이터에 대해 FTD level 5를 만족시킬 수 있는 QTG작성에 대해 연구하였다. 모델은 Cirrus사(社)의 SR-20을 대상으로 하였다. QTG의 테스트항목 중에는 조종반력을 측정하는 항목도 있다. 따라서 Brunner사(社)의 CLS(Control Loading System)을 조종 장치에 설치하여 조종반력을 측정할 수 있도록 구성하였다. X-Plane은 자체적으로 트림루틴을 제공하지 않으므로 외부에서 Autopilot을 구성하여 항공기가 트림상태에 도달할 수 있도록 하였다. 또한 테스트를 자동으로 수행할 수 있는 알고리듬을 개발하여 수동으로 조종하여 테스트하는 번거로움을 피하고 같은 테스트를 같은 조건으로 진행할 수 있도록 하였다. FTD Level 5의 경우 실제 비행데이터가 아닌 alternative data source를 적용할 수 있으며 이를 활용하여 모든 테스트 결과가 주어진 범위를 만족하였다.

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.225-237
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• 2018

The difficulties of satellite vibration testing are due to the commonly expressed qualification requirements being incompatible with the limited performance of the entire controlled system (satellite + interface + shaker + controller). Two features cause the problem: firstly, the main satellite modes (i.e., the first structural mode and the high and low tank modes) are very weakly damped; secondly, the controller is just too basic to achieve the expected performance in such cases. The combination of these two issues results in oscillations around the notching levels and high amplitude beating immediately after the mode. The beating overshoots are a major risk source because they can result in the test being aborted if the qualification upper limit is exceeded. Although the abort is, in itself, a safety measure protecting the tested satellite, it increases the risk of structural fatigue, firstly because the abort threshold has been already reached, and secondly, because the test must restart at the same close-resonance frequency and remain there until the qualification level is reached and the sweep frequency can continue. The beat minimum relates only to small successive frequency ranges in which the qualification level is not reached. Although they are less problematic because they do not cause an inadvertent test shutdown, such situations inevitably result in waiver requests from the client. A controlled-system analysis indicates an operating principle that cannot provide sufficient stability: the drive calculation (which controls the process) simply multiplies the frequency reference (usually called cola) and a function of the following setpoint, the ratio between the amplitude already reached and the previous setpoint, and the compression factor. This function value changes at each cola interval, but it never takes into account the sensor signal phase. Because of these limitations, we firstly examined whether it was possible to empirically determine, using a series of tests with a very simple dummy, a controller setting process that significantly improves the results. As the attempt failed, we have performed simulations seeking an optimum adjustment by finding the Least Mean Square of the difference between the reference and response signal. The simulations showed a significant improvement during the notch beat and a small reduction in the beat amplitude. However, the small improvement in this process was not useful because it highlighted the need to change the reference at each cola interval, sometimes with instructions almost twice the qualification level. Another uncertainty regarding the consequences of such an approach involves the impact of differences between the estimated model (used in the simulation) and the actual system. As limitations in the current controller were identified in different approaches, we considered the feasibility of a new controller that takes into account an estimated single-input multi-output (SIMO) model. Its parameters were estimated from a very low-level throughput. Against this backdrop, we analyzed the feasibility of an LQG control in cancelling beating, and this article highlights the relevance of such an approach.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.224-227
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• 2007

This paper introduces the results of acoustic loads test conducted on the upper stage assembly of KSLV-I, which is the first Korea space launch vehicle. A launch vehicle and its payloads are subjected to severe acoustic pressure loading when they lift off and ascent during the transonic periods. Acoustic loadings are spreaded out broad frequncy-spectrum up to 10,000Hz. Acoustic loads are a primary source of structural random vibration of the upper stage and payloads. Therefore, in order to verify the structural integrity of the upper stage assembly of KSLV-I and the survivability of its components under severe random vibration environment, acoustic loads test is conducted in the high intensity acoustic chamber with 142dB (overall SPL). The results show the structural design and component random vibration specifications well meet with the environmental requirements.

• 한국산학기술학회논문지
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• 제18권6호
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• pp.90-102
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• 2017

최근 들어 학교 밖 청소년들의 수가 증가하고 있으며 이들의 진로문제가 중요한 청소년 문제로 대두되고 있다. 본 연구의 목적은 고졸검정고시를 준비하는 학교 밖 청소년들이 지각한 진로장벽과 사회적 지지의 유형 및 사회적 지지원 간의 관계를 밝히고, 이들의 지각한 사회적 지지가 소외감을 매개로 하여 진로장벽에 영향을 미치는지를 알아보는 것이다. 이를 위해 전국 5개 권역의 청소년지원센터 꿈드림(학교 밖 청소년지원센터)과 검정고시 학원의 학교 밖 청소년 207명을 대상으로 사회적지지, 진로장벽, 소외감에 대한 설문을 실시하였다. 또한 상관분석과 회귀분석과 Sobel test를 활용하여 변인간의 관계와 소외감의 매개효과를 분석하였다. 그 결과, 지각된 사회적 지지는 진로장벽, 소외감과 유의한 부적상관이 있었으며, 소외감과 진로장벽은 유의한 정적상관이 있는 것으로 나타났다. 진로장벽과 소외감은 사회적지지 중에서도 부모의 지지와 평가적 지지와 가장 높은 부적상관을 보였다. 또한 소외감은 부모지지 및 교사 지지와 진로장벽 간의 관계를 완전매개 하였으며, 친구지지와 진로장벽 간의 관계를 부분매개 하였다. 소외감은 정보적, 물질적, 평가적, 정서적 사회적 지지의 모든 유형과 진로장벽 간의 관계를 완전매개 하였다. 이는 고졸 검정고시를 준비하는 학교 밖 청소년들의 경우 부모 및 교사, 친구들이 제공하는 여러 유형의 사회적 지지를 향상하여 소외감을 낮춰줌으로써 진로장벽을 낮춰갈 수 있다는 것을 시사한다.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2387-2395
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• 2021

Seismic qualifications of electrical equipment, such as cabinet systems, have been emerging as the key area of nuclear power plants in Korea since the 2016 Gyeongju earthquake, including the high-frequency domain. In addition, electrical equipment was sensitive to the high-frequency ground motions during the past earthquake. Therefore, this paper presents the rocking behavior of the electrical cabinet system subjected to Reg. 1.60 and UHS. The high fidelity finite element (FE) model of the cabinet related to the shaking table test data was developed. In particular, the first two global modes of the cabinet from the experimental test were 16 Hz and 24 Hz, respectively. In addition, 30.05 Hz and 37.5 Hz were determined to be the first two local modes in the cabinet. The high fidelity FE model of the cabinet using the ABAQUS platform was extremely reconciled with shaking table tests. As a result, the dynamic properties of the cabinet were sensitive to electrical instruments, such as relays and switchboards, during the shaking table test. In addition, the amplification with respect to the vibration transfer function of the cabinet was observed on the third floor in the cabinet due to localized impact corresponding to the rocking phenomenon of the cabinet under Reg.1.60 and UHS. Overall, the rocking of the cabinet system can be caused by the low-frequency oscillations and higher peak horizontal acceleration.