• Title, Summary, Keyword: Pyroshock

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On the Characteristics of Pyroshock Simulator (파이로충격 모사장비 특성분석)

  • Chun, Young-Doo;Im, Jong-Min;Seo, Sang-Hyun;Chung, Eui-Seung;Cho, Gwang-Rae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.172-175
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    • 2005
  • Since, similar to other commercial launch vehicles, various kinds of pyrotechnique devices are used in the KSLV-I(Korea Space Launch Vehicle), the electronic equipment on the vehicle equipment bay is exposed to the sever pyroshock environment during Pyrotechnique device detonation. In order to confirm the survivability of electrical instruments from these pyroshock conditions, shock tests are performed by using a pyroshock simulation during development and qualification phase. In this paper, the pyroshock simulator installed in KARI(Korea Aerospace Research Institute) are briefly introduced, and its performance of pyroshock generating is compared with the measured shock response spectrums from small scaled fairing jettisoning tests. The results show that the pyroshock simulator is still proper to generate severe pyroshocks similar to real pyrotechique detonating conditions, but the redesign on the test jigs is necessary to improve its test performance.

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Pyroshock Measurement and Characteristic Analysis of Explosive Bolt and Pyrotechnic Initiator (폭발볼트와 착화기의 파이로충격 계측 및 특성 분석)

  • Lee, Juho;Hwang, Dae-Hyun;Jang, Jae-Kyeong;Lee, YeungJo;Kim, Dong-Jin;Lee, Jung-Ryul;Han, Jae-Hung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.2
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    • pp.213-220
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    • 2017
  • Pyroshock produced by the pyrotechnic devices can induce failures in nearby electronic devices. To handle and mitigate pyroshock inducing problems, appropriate measurement of pyroshock is essential. In this study, pyroshock measurement technique is established using laser Dopper vibrometers (LDVs) and shock accelerometers. Pyroshock produced by the explosive bolts and the pyrotechnic initiators under various environments is measured. The characteristics of pyroshock including the effects of supporting structures, propagation form on thin plate, sensor (contact and non-contact) types are discussed.

Pyroshock measurement results of satellite mock-up for launch vehicle (발사체 목업(Mock-up) 위성의 파이로 충격 측정 결과)

  • Youn, S.H.;Jeong, H.K.;Seo, S.H.;Jang, Y.S.;Yi, Y.M.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.363-366
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    • 2006
  • In general, pyrotechnic shock or pyroshock is generated during the operation of separation devices, which use explosives, such as pyrobolt, puronut, purocutter, linear shape charge, and so on. During the flight of launch vehicle, pyroshock is mainly produced at the events of satellite separation, fairing separation and stage separation. In this paper, characteristics of pyroshock are introduced in the first place and measured shock result data at the UMR of satellite mock-up during the separation tests of satellite and fairing are suggested. These results are compared with the suggested pyroshock test specification of satellite, and it finally confirms that the specification is reasonable for the qualification of satellite against pyroshock.

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Pyroshock Isolation Performance Test using Wiremesh Isolators (와이어메쉬 절연계의 파이로 충격 절연 성능 시험)

  • Youn, Se-Hyun;Jang, Young-Soon;Han, Jae-Hung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.9
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    • pp.923-928
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    • 2008
  • Pyrotechnic shock or pyroshock is characterized as a transient vibration phenomenon which shows large acceleration and high frequency range up to 10kHz during the operation of separation devices where explosives are used. During the flight of a launch vehicle, pyroshock is mainly generated at several events such as satellite separation, fairing separation and stage separation. In this paper, wiremesh isolators are introduced and several types of isolators are manufactured for the performance tests. For the investigation of typical characteristics of wiremesh isolators, compressive loading tests are basically performed and pyroshock tests are accomplished to confirm pyroshock isolation ability of each wiremesh isolator by using 4Kg dummy mass.

Pyroshock and Vibration Characteristics of PEEK Washer Shock Absorbers (PEEK 와셔를 적용한 충격저감장치의 파이로 충격 및 진동 특성)

  • Youn, Se-Hyun;Jang, Young-Soon;Han, Jae-Hung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.3
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    • pp.285-290
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    • 2008
  • Pyrotechnic shock or pyroshock is characterized as a transient vibration phenomena which shows large acceleration and high frequency range up to 10kHz during the operation of separation devices where explosives are used. During the flight of a launch vehicle, pyro-shock is mainly generated at several events such as satellite separation, fairing separation and stage separation. In this paper, characteristics of pyroshock are introduced briefly, and PEEK washer shock absorber is applied for the reduction of pyroshock in the high frequency range. With some electronic devices, reduction characteristic of pyroshock using washer type shock absorber are studied. Random vibration tests are also performed for the verification of vibrational characteristics.

The Parametric Study of the Design Variables on the SRS of Pyroshock Resonant Bar (파이로 충격 모사 시험 장치 주요 매개변수에 따른 SRS 분석)

  • Jeon, Hyeonkyu;Kim, Munguk;Kim, Minsung;Kwon, Yeongmin;Yu, Yejin;Kim, In-Gul
    • Journal of the Korea Institute of Military Science and Technology
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    • v.21 no.4
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    • pp.413-421
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    • 2018
  • The pyroshocks can cause failure of electronics devices and structures. Metal-metal impact methods are utilized to simulate mechanical pyroshock, and to adjust the knee frquency of the SRS(Shock Response Spectrum) through resonant structures. In this paper, the major parameters of pyroshock simulation device which affect the SRS were examined. Through the Hertzian contact law and the modal characteristics of the resonant bar, it was found that the SRS is affected by the length and mass of a bar and various impact conditions such as velocity and mass of impactor. The characteristics due to the geometric parameters of a resonant bar was analyzed by performing FEA and also the resonant bar was designed and fabricated. Through the pyroshock simulation test, the characteristics of SRS due to the variation of impact parameters were examined.

Pyroshock and Vibration Isolation using SMA Mesh Washer Isolator (형상기억합금 메쉬 와셔 절연계의 파이로 충격 및 진동 절연 시험)

  • Youn, Se-Hyun;Jang, Young-Soon;Han, Jae-Hung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.3
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    • pp.307-313
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    • 2009
  • In general, pyroshock is generated from the actuation of separation devices for several stage, fairing, and satellite separation in the flight of a launch vehicle. During these events, transient vibration phenomenon called pyroshock, which shows large acceleration in the high frequency range, occurs and it can result in the malfunction of electronic components which is equipped inside the launch vehicle or satellite. In this paper, mesh washer isolators made out of SMA were introduced for the isolation of pyroshock. One type of isolator primarily used pseudoelastic characteristics of SMA and the other type of isolator used shape memory effect of SMA. For the study of basic load-displacement relationship of each SMA isolator, compressive loading tests were performed and the results showed the capability of the isolator itself. Pyroshock isolation tests were followed and verified the outstanding isolation performance of isolator. In addition, random vibration tests were also performed and checked the dynamic characteristics of each SMA isolator.

Pyroshock Prediction of the Satellite Launch Vehicle at the Payload Fairing Separation (인공위성 발사체 노즈페어링 분리 시 구조물의 충격량 예측)

  • Jeong, Ho-Kyeong;Youn, Se-Hyun;Park, Soon-Hong;Jang, Young-Soon;Lee, Yeoung-Moo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.250-253
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    • 2005
  • This paper is investigates the separation shock of payload fairing. Separation test of subscale PLF using half separation device and half PLA is performed. Resulting shock loads at equipment bay and fairing joint are measured. Pyroshock estimation is performed using AUTOSEA Pyroshock Module. Input data to analysis model is obtained from the separation test results of subscale PLF. And model of AUTOSEA is updated comparing results between tests and analysis.. This enables us to validate the AUTOSEA model. Tuned model of subscale PLF and separation device is used to update full scale model, and the shock analysis result of full scale model is estimated in this paper. This paper also discusses the results regarding the difficulty of structural modeling and its numerical implementation in AutoSEA2 Software.

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Comparisons of Isolation Performances for the SMA Mesh Washer Isolator with the Variation of Pre-compressed Displacement (초기압축변위에 따른 형상기억합금 메쉬 와셔 절연계의 절연 성능 비교)

  • Youn, Se-Hyun;Jeong, Ho-Kyeong;Han, Jae-Hung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.2
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    • pp.162-168
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    • 2011
  • Launch vehicles and satellites experience severe vibration and pyroshock during the flight phase. These severe dynamic loading could result in the malfunction of electric devices which equipped in the launch vehicle and satellite. In this paper, mesh washer isolators are applied to attenuate these severe shock and vibration and isolation performances are enhanced by applying pseudoelasitic SMA wire material. Through random vibration and ground pyroshock tests, outstanding isolation performances are studied. Especially, comparison of isolation performances due to the change of pre-compressive displacement of mesh washer itself are suggested and applicablity to the adaptive vibration control are confirmed.

The Application of Pyrotechnic Shock in Korean Aerospace Program (한국 우주개발분야의 충격시험 적용사례)

  • Lee, Sang-Seol;Kim, Hong-Bae;Moon, Sang-Mu;Woo, Sung-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1161-1168
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    • 2000
  • The tenn "Pyrotechnic Shock" or "Pyroshock" is used to describe short duration, high amplitude and high frequency transient structural responses in aerospace vehicle structures..The transients are generally initiated by firing of an ordnance item to separate or release a structural member of fastener. The objective of this paper is to present a set of pyrotechnic shock environment information - specific characteristics induced by many separation devices, prediction, testing, measurement and analysis methods of pyroshock environment. In addition, it is introduced the application of pyrotechnic shock test in Korean aerospace development program.

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