• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.267-270
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• 2007

한국항공우주연구원은 호주 University of Queensland(UQ)와 2006년 10월 스크램제트 엔진 성능시험 계약을 체결하고, 2007년 6월 UQ의 T4 Free Piston shock tunnel에서 마하 7.6, 고도 31.2 km 조건에서 스크램제트 엔진의 지상 성능시험을 수행하였다. 본 논문에는 T4 충격파 터널의 구조 및 데이터 취득 기법에 대하여 정리하였다.

• 한국군사과학기술학회지
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• 제8권3호
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• pp.73-82
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• 2005

This paper describes shock waveform synthesis methods for a shock response spectnlm over a short time interval with which intereference between parts within a test item is increased to perform a sufficient shock test for damage or malfunction which may be caused by the interference between parts, and a digital filter for obtaining a shock response history required for the shock waveform synthesis and a digital inverse filter for restoration by inversely using the digital filter. The time at which the maximax value occurs in the response history is detected in order to establish a delay time which is one of the parameters in the wavelet, on the condition that the natural frequency of SDOF system with a Q (quality factor) of 10 equals to the wavelet frequency of the zero delay wavelet input. A shock response spectrum over a short time interval and an abrupt change in the acceleration for an instant are illustrated as features of the synthesized waveform.

• 한국운동역학회지
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• 제22권2호
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• pp.237-242
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• 2012

The purpose of this study was (a) to develop carbon nanotube-based shock absorbers for reducing potentially harmful impact forces and excessive foot pronation, and (b) to briefly determine how the effects of carbon nanotube-based shock absorbers on biomechanical variance during drop landing. A university student(age: 24.0 yrs, height: 176.2 cm, weight: 679.5 N) who has no musculoskeletal disorder was recruited as the subject. Hardness, specific gravity, tensile strength, elongation, 100% modulus, tear strength, split tear strength, compression set, resilience, vertical GRF, and loading rate were determined for each material. For each dependent variable, a descriptive statistics was used for different conditions. The property test results showed that tensile strength, tear strength, split tear strength, compression set, and resilience in carbon nanotube-based shock absorbers were greater than general Ethylene Vinyl Acetate(EVA). These indicated that resistance against variable strength in developed carbon nanotube-based shock absorbers were greater than general EVA. In vertical GRF of CNTC was less than those of EVA during drop landing and loading rate of CNTC was greater than EVA. It seems that the use of CNT can be a effective way of reducing and controlling shock from impact.

• 대한조선학회논문집
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• 제38권3호
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• pp.117-122
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• 2001

함정에 탑재되는 주요장비는 내충격성능을 확인하기 위해 충격시험을 실시하고 계측된 신호는 최대충격가속도, 지속시간, 응답스펙트럼 등 충격응답신호의 신간이력을 분석한다. 그러나 계측된 신호는 배경잡음, 계측기오차, 케이블의 과도운동 등으로 충격성잡음과 백색잡음으로 인한 신호왜곡이 발생할 수 있으므로 충격시험으로부터 정확한 시간이력을 추출하기 위해서는 이러한 잡음을 제거해야 한다. 충격성잡음은 중간값필터를 이용하여 제거하고 백색잡음은 웨이블렛의 계수값을 축소함으로써 잡음이 제거된 충격응답신호의 시간이력으로부터 정도높은 최대충격, 지속시간 및 충격응답스펙트럼이 획득가능하다. 제안된 기법의 타당성을 판단하기 위해 수치 시뮬레이션을 수행한 결과 신호대잡음비가 30dB 이상 향상되었음을 확인하였고, 실제계측된 수중폭발충격신호에 적용시켜 향상된 충격응답스펙트럼을 추출하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권3호
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• pp.169-175
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• 2014

In this paper, the evaluating test methods of the fire and the electric shock on the Electric pad using the house is proposed. We analyzed electric pad using magnetic shielded type hot wire because electric pad using the magnetic shielded type hot wire generally be used in the home. We analyzed FMEA in order to analyze the mechanism of the fire and the electric shock of the electric pad and designed testing methods (Durability tests on the environment, Mechanical durability tests, Electrical durability tests) obtained through the two-step QFD and tested. We verified the evaluating test methods of the fire and the electric shock on the Electric pad using the house through the analysis of the test results.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.214-215
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• 2005

Naval equipments are installed and used for naval vessel with different environmental conditions comparing to the commercial vessel, for example, high engine power per ship displacement size, severe vibration and shock due to high running speed and explosion from naval gun's bombardment and underwater weapons. Therefore, those equipments must be installed on shipboard with small spaces, high ambient temperature around engine room and which are required be fabricated with high resistances of vibration, shock and heat resources. But in case of commercial vessel, the performances of their recent equipments naval have been improved continuously due to the technology development of domestic shipbuilding and shipboard equipment industries, together with the related fundamental industries i.e, metal, steel and electronic industries, to an international level since 1970. With these results, it became possible to unify the specifications of shipboard equipments for the commercial and military vessels(Dual-Use). In this study, vibration and shock test standards for the commercial and military vessels will be compared and reviewed technically.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.163-169
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• 2015

In this paper, the evaluating test methods of the fire and the electric shock on the led lamp supply using the house is proposed. We analyzed FMEA in order to analyze the mechanism of the fire and the electric shock of the led lamp supply and designed durability tests on the environment ($85^{\circ}C$, 85% R.H.) and obtained through the two-step QFD and tested. We verified the evaluating test methods of the fire and the electric shock on the led lamp supply using the house through the analysis of the test results.

• 대한기계학회논문집A
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• 제38권6호
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• pp.663-668
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• 2014

기계 및 전자 장비들은 다양한 분야에 여러 형태로 사용되고 있어 충격과 같은 외부 환경에 노출되어 있다. 장비들의 내충격 특성을 평가하기 위해 충격시험장치가 사용되고 있으며, 과도한 응력의 발생에 의한 영구 변형이나 파손, 높은 가속도에 의한 장비 내부 부품의 파손 및 기능정지 등에 대한 평가가 이루어 진다. 이러한 충격시험장치에 있어서 물체를 고속으로 움직이게 하여 물체간의 충격을 유발할 수 있는 속도발생기가 필요하다. 본 연구에서는 유공압을 이용하여 물체를 고속으로 움직일 수 있게 하는 속도발생기를 개념적으로 설계하고, AMESim을 이용한 해석모델을 통하여 발생 속도를 예측하였다. 해석 결과는 축소 제작된 속도발생기의 시험 결과와 비교하여 검증하였으며, 해석 결과를 이용하여 목표 속도에 적합한 속도발생기를 설계하였다.

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.177-186
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• 2018

This paper deals with the idea to replace the usual high-level sine sweep test on shaker at system level, very severe, by a low level one completed by a transient test in the same configuration, in order to be more representative of the real environment, thus limiting over testing and improving the payload comfort. The problem of the transient test specification is first discussed. The proposed solution is to derive from LV/SC coupled analyses a shock response spectrum corresponding to two damping ratios. Then, the question of adequate shock synthesis is tackled. A new method with a given spectrum is considered for better potential and accuracy than the usual wavelets. A campaign on the Intespace bi-shaker devoted to system level showed its capability to perform the resulting test with one spectrum. First investigations to extend this approach to two spectra are in progress.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.250-254
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• 2011

Main role of landing gear is to absorb the energy which is generated by aircraft lanidng and ground maneuvering. Generally, in order to absorb the impact energy during landing, oleo-pneumatic type shock absorber is used for aircraft landing gear. Oleo-pneumatic type shock absorber has a good energy absorbing efficiency and is light in weight because its structure is relatively simple. For the landing gear development, it is necessary to conduct drop test in order to verify shock absorbing performance. In the drop test, first, gas spring curve verification tests are conducted. Then, limit and reserve energy absorption drop tests are performed based on the STANAG 4671. The drop tests results with performance analysis results are presented.