• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.242-245
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• 2006

This paper is an assessment on the dynamic test results of optical bench for LEO satellite. According to the design requirements, optical bench was designed and manufactured. Dynamic test was performed to verify stability of optical bench. Low level random vibration test, sine burst test and sine vibration test are carried out to identify dynamic characteristics and to verify static strength and safety under quasi-static load conditions. From the result it can be stated that the optical bench is well qualified under the launch environmental conditions.

• 한국위성정보통신학회논문지
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• 제5권1호
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• pp.80-84
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• 2010

위성 구조계의 가장 기본적인 임무 및 역할은, 우선 위성 자체의 미션 및 기능을 위해 필요한 여러 탑재체 및 장비들을 장착하고 지지할 수 있는 공간을 제공하고, 발사 시에 발생하는 이런 극심한 발사환경 하중에서 위성체 및 탑재체들을 안전하게 보호하는 것이다. 위성체가 발사체에 실려 발사될 때에 매우 높은 가속도에 의한 정적하중 및 공기의 저항에 의한 하중, 연소 가스 분출 시 발생하는 음향에 의한 하중, 발사체로부터 분리될 때 발생하는 충격 하중 등 여러 가지의 극심한 하중을 겪게 된다. 이런 여러 발사환경 중, 저주파 동적 하중 환경의 검증을 위한 정현파 가진 시험 시에 주요 탑재체 및 장비들의 고유모드에서 과도한 하중이 가해지는 것을 피하기 위해 정현파 가진 규격에 노칭을 적용하게 된다. 본 논문은 정현파 가진 시험을 주요 내용으로 하며, 시험을 수행하기 위한 노칭된 예측 입력하중과 실제 시험에 사용된 입력하중을 비교하여 유한요소모델 및 예측의 정확성을 확인해 보고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.747-750
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• 2004

After launching, spacecraft is exposed to extreme environments. So spacecraft should be tested after design/manufacture to verify whether components can be operated functionally. Acceleration transferred from launch vehicle to spacecraft produces quasi-static load, sine vibration and random vibration. Random vibration is also induced by acoustic vibrations transferred by surface of spacecraft. And shock vibration is produced when spacecraft is separated from launch vehicle. To verify operation of spacecraft under these launch environments, separation shock test, sine vibration test, acoustic vibration test and random vibration test should be performed. This paper describes these launch environment test requirements.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.966-970
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• 2005

On the basis of the development of KSLV-1, KoDSat was designed and manufactured to demonstrate the performance of KSLV-1. KoDSat is exposed to a severe vibrational environment at launch. The structural reliability of KoDSat has to be verified using vibrational test. The structural compatibility and verification of components between analysis and test can be proved using environmental vibration test. In this paper, we review the structural characteristic of thruster control unit for a space launch vehicle and design TCU housing using mathematical model. In order to verify the structural compatibility and reliability, half-sine shock, random and sing sweep vibration test was performed. Especially, sing sweep vibration test result is compared with analysis result and mathematical model is verified.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.119-122
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• 2002

인공위성 발사 시 안테나를 비롯한 탑재체는 극심한 진동을 경험하게 된다. 따라서 공진에 의한 구조물의 파손을 방지하기 위해 지상 인증시험을 수행하게 되며, 이를 위하여 구조 동해석을 통해 인증시험에 적용되는 적정 하중값을 결정하는 과정이 선행된다. 본 논문에서는 복합재료로 이루어진 Ka 대역 안테나 구조물의 동해석을 위하여 자유진동해석과 정현파 진동해석을 수행하고, 그 결과로서 진동시험 시 구조물의 인증시험에 요구되는 적정 하중값을 노칭기법을 이용하여 산출하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.581-586
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• 2014

In general vibration test considers both harmonic vibration and random vibration, When developing the vehicle component. But the effect of harmonic vibration is larger in the parts around the vehicle engine, sole testing the harmonic vibration is considered. In this study, the fatigue damage of the linear system fixed around the engine is analyzed when the effect of random vibration is higher, harsher than the normal road surface condition. In condition the vehicle speed and the engine RPM are similar, the higher the harshness of the road surface condition is, the larger the fatigue damage level is. Therefore both random vibration and harmonic vibration must be considered in vibration test of components around the engine. Proposing the sine on random(SOR) vibration test that can exam considering both of vibrations, harmonic and random.

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.187-204
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• 2018

The sine sweep base excitation test campaign is a major milestone in the process of mechanical qualification of space structures. The objectives of these vibration tests are to qualify the specimen with respect to the dynamic environment induced by the launcher and to demonstrate that the spacecraft FE model is sufficiently well correlated with the test specimen. Dynamic qualification constraints lead to performing base excitation sine tests using a sine sweep over a prescribed frequency range such that at each frequency the response levels at all accelerometers, load cells and strain gages is the same as the steady state response. However, in practice steady state conditions are not always satisfied. If the sweep rate is too high the response levels will be affected by the presence of transients which in turn will have a direct effect on the estimation of modal parameters. A study funded by ESA and AIRBUS D&S was recently carried out in order to investigate the influence of sine sweep rates in actual test conditions. This paper presents the results of this study along with recommendations concerning the choice of methods.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.587-591
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• 2012

Review of practical vibration test methods those applied in various industrial fields - such as automotive industry, electrics and electronics industry, defense industry and aerospace industry - is described on this paper. Swept sine test, random vibration test and advanced vibration techniques are explained according to their parametric values and also application fields of each test method are suggested by the characteristic of each method. For more proper application of each test method, standardized test specifications should be always reviewed and revised according to the transition of environmental factors.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.515-518
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• 2006

A vibration test for a cylindrical rod inserted on the grid support structure was tested using the sine sweep excitation method with closed loop force control. The effect of the mounting location of a test rod on the vibration characteristics of a rod continuously supported by the full size($16{\times}16$) grid support was identified. An electromagnetic vibration shaker, non-contact displacement sensor and HP/VXI data acquisition device were used and TDAS software was also used as a data sampling and processing tools. The natural frequencies and mode shape of the test rod were consistent with the previous works of a rod vibration test with partial grids($3{\times}3,\;5{\times}5\;and\;7{\times}7$). The frequency characteristics of the rod according to the mounting location were shown clear discrepancies, but mode shapes were nearly same. As the test rod closes to the bottom clamping region of the spacer grid, peak vibration amplitudes of the rod become smaller.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.4776-4783
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• 2014

1차 소음원을 저감시키기 위한 많은 연구가 진행되어 왔지만 BSR과 같은 감성품질에 대한 연구는 상대적으로 적다. 본 논문은 다축 가진기를 이용한 시트 프레임의 BSR 시험을 실시한다. 정현파 스윕(sine wave sweep) 테스트를 실시하여 BSR 소음과의 관계를 연구하고 시트 프레임의 진동 내구 시험 전후 BSR 시험을 실시한다. 그 결과 첫 번째 수평(lateral)방향 공진이 고주파의 BSR소음을 발생시키며 또한 레일의 위치에 따라 BSR 소음 특성이 변하는 것을 확인했다. 또한 시트 프레임의 내구 시험 후 시스템 강성이 감소하였고, 그에 따라 BSR 소음이 감소되는 것을 확인할 수 있었다.