• Title/Summary/Keyword: resonacne

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Measurements o Elastic Moduli of Rock Cores Using Free-Free Resonacne Tests (자유단 공진시험을 이용한 암석의 탄성계수 측정)

  • 목영진
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.4
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    • pp.95-100
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    • 1999
  • Dynamic measurements are used rather sparingly to determine the elastic modull of rock cores and modulus values are not much utilized in design practice. The reason seems to result from the general perception that values obtained by dynamic measurement are much higher (about 10 times) than those determined statically. This paper presents results from dynamic and static tests on rock cores. The findings are: 1) elastic modull can be consistently determined by laboratory seismic testing. 2) nonlinear deformation characteristics of rock cores was tentatively proposed with variation in elastic modulus with strain.

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Dynamic Modeling of the Free Piston Stirling Pump for the Passive Safety Injection of the Next Generation Nuclear Power Plant (차세대 신형원자로의 피동형 안전 주입장치를 위한 프리피스톤 스터링 펌프의 동특성 모델)

  • Lee, Jae-Young
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1999.11a
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    • pp.149-154
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    • 1999
  • This paper describes a passive safety injection system with free piston Stirling pump working withabundant decay heat in the nuclear reactor during the hypothetical accident. The water column in the tube assembly connected from the hot chamber to the cold chamber in the pump oscillates periodically due to thermal volume changes of non-condensable gas in each chamber. The oscillating pressure in the water column is converted into the pumping power with a suction-and-bleed type valve assembly. In this paper a dynamic model describing the frequency of oscillation and pumping pressure is developed. It was found that the pumping pressure is a function of the temperature difference between the chambers. Also, the frequency oscillation depends on the length of the tube with water column.

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Design for improving the impact resistance of a vehicle equipped with the circuit card assembly (비행체 탑재 회로카드 조립체의 내충격 향상을 위한 설계)

  • Lee, Chang-Min;Kang, Dong-Suk;Shin, Young-Hoon;Lee, Ki-Sun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.48-53
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    • 2014
  • Rocket, held using the CCA for the mission, a plurality of recording devices, and navigation equipment. In case of a projectile which is entered the water after fired into the air, after performing stages and fairing separated in flight to enter the underwater. It is caused by the explosion of gunpowder mainly, vibration phenomenon of a large transition is induced structurally very, also on entering the water, have a significant shock structurally separated. If shock is transmitted directly to the CCA through the body, it can be caused malfunction of payloads, resulting in failure of the mission of the projectile. In order to ensure the stability against shock, in this paper, Calculating a target resonacne frequency of the CCA, and verified through modal test and analysis. Maximum acceleration position of CCA is checked by SRS analysis. In addition, effectiveness of shock isolation system through shock analysis.

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