• Title, Summary, Keyword: Shock Response Spectrum

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Analysis of Shock Mechanism and Actuator Behavior of HDD (내충격성 향상을 위한 HDD Actuator의 거동 연구)

  • 손진승;좌성훈;이행수;홍민표
    • Journal of KSNVE
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    • v.11 no.3
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    • pp.449-454
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    • 2001
  • The shock performance of hard disk drives has been a serious issue for portable computers and AV application HDD. Focusing on the motion of an actuator, we investigated non-operational shock mechanism and studied several parameters that affect the shock performance by experimental analysis. It was found that there are two important factors fort the actuator to endure high shock revel. One is a shock transmissibility and the other is a beating between the arm blade and the suspension. To generalize the shock transmissibility, the concept of shock response spectrum was introduced. The shock response spectrum of the actuator system was obtained experimentally and compared with that of an analytical single degree of freedom model. It was found that there was a good agreement. The first bending natural frequency of the arm blade was found to be the most important factor for the low shock transmissibility. By applying the shock response spectrum and avoiding the beating, we could design an actuator of high shock performance.

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Shock Waveform Synthesis for Shock Response Spectrum Test by Using Wavelets (충격반응 스펙트럼 시험에서 웨이브레트를 이용한 충격파형 합성)

  • 윤을재
    • Journal of the Korean Society of Propulsion Engineers
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    • v.2 no.2
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    • pp.88-98
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    • 1998
  • A waveform for shock response spectrum test on a shaker is synthesized using wavelets such that a specified shock response spectrum of a test profile is achieved. The parameters of a wavelet are center frequency, amplitude, number of half cycles, delay and polarity. The amplitude of each wavelet component is iteratively adjusted so a specified shock response spectrum is matched. The waveform so synthesized is regarded as a reference acceleration waveform for a shaker shock response spectrum test. The author proposes the use of a long duration and low peak waveform. The usefulness of this approach is illustrated with some examples.

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Analysis for Driving Shock Resistance of Military Vehicle (군용 차량 주행 내충격 분석)

  • Jeon, Jong-Ik;Lee, Jong-Hak;Jeong, Eui-Bong;Kang, Kwang-Hee;Choi, Ji-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.267-272
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    • 2014
  • In this paper, we analyze the characteristics for the driving shock resistance of the military vehicle through the bump test. Prior to the experiment, theoretical analysis was performed by using the SRS(shock response spectrum) and VRS(vibration response spectrum) analysis method. And we estimated the characteristics for the driving shock resistance of the military vehicle. Bump test was performed using the acceleration sensor and the driving test at a different speed. We evaluated the characteristics for the driving shock resistance of the military vehicle based on the result. And predicted values were compared with the theoretical analysis. In addition, we evaluated the results of the theoretical prediction of the SRS and the VRS analysis. And we evaluate the suitability of the prediction method at military vehicle shock analysis.

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Shock Waveform Synthesis Methods for Shock Response Spectrum over Short Time Interval, Digital Filter for Obtaining Shock Response History and Applications Thereof (충격응답 스펙트럼이 나타나는 시간들의 차이가 짧은 충격파형의 합성방법 및 충격응답 내역을 구하는 디지털 필터)

  • Yoon, Eul-Jae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.3
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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.

Firing Shock Measurement and Shock Response Spectrum Analysis of Small Arms (소구경 화기의 사격충격 측정 및 충격응답스펙트럼 분석)

  • Lee, Joon-Ho;Choe, Eui-Jung;Yoon, Joo-Hong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.588-593
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    • 2012
  • Nowadays, various forms of electro-optical rifle scope have been developed and used in order to enhance the accuracy of small arms. However, firing shock acceleration has characteristics of pyroshock having a big acceleration value with very short duration time, which the electro-optical scopes should be designed to sustain. In this paper, the firing shock acceleration, which is transmitted to the electro-optical scope, was measured and SRS (Shock Response Spectrum) analysis was performed by using the measured firing shock acceleration. Furthermore, a shock test condition using a drop-table shock tester, which can simulate the actual firing shock acceleration, was devised. The devised shock test condition will be utilized to test the electro-optical scope itself before attaching it to the small arms.

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Multi-point response spectrum analysis of a historical bridge to blast ground motion

  • Haciefendioglu, Kemal;Banerjee, Swagata;Soyluk, Kurtulus;Koksal, Olgun
    • Structural Engineering and Mechanics
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    • v.53 no.5
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    • pp.897-919
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    • 2015
  • In this study, the effects of ground shocks due to explosive loads on the dynamic response of historical masonry bridges are investigated by using the multi-point shock response spectrum method. With this purpose, different charge weights and distances from the charge center are considered for the analyses of a masonry bridge and depending on these parameters frequency-varying shock spectra are determined and applied to each support of the two-span masonry bridge. The net blast induced ground motion consists of air-induced and direct-induced ground motions. Acceleration time histories of blast induced ground motions are obtained depending on a deterministic shape function and a stationary process. Shock response spectrums determined from the ground shock time histories are simulated using BlastGM software. The results obtained from uniform and multi-point response spectrum analyses cases show that significant differences take place between the uniform and multi-point blast-induced ground motions.

A Study on the Shock Analysis of the Multi-Function Console According to the Shock Response Spectrum Requirements of the Elastic Platform (탄성플랫폼 충격응답 스펙트럼 기준에 따른 다기능콘솔 충격해석 연구)

  • Park, Jae Hoon;Kim, Won Hyung;Kim, Hyun Sil;Choi, Young Cheol
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.10
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    • pp.805-811
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    • 2016
  • Prior to installation in a navy ship, shipboard equipment should be qualified by shock test requirements. The multi-function console mounted on the elastic platform of the ship should also withstand given shock loads. In this study, both real shock test methods, as well as numerical computer simulations using the finite element method were used to verify structural durability under shock load conditions. First, we used domestic test facilities to perform possible shock tests, including an impact hammer test, a drop table test and a shaker shock test. Full model tests satisfying the shock response spectrum level were performed. Thereafter, an analytical model of the complex console structure was built by the finite element method. Finally, numerical results were verified by modal test results of the real product and an FEA analysis was also performed with a full model transient response analysis.

A Numerical Study on the Shock Behavior of Multi-layered Panels (다층 패널의 피탄충격거동에 관한 수치해석적 연구)

  • Park, Chan-Young;Yang, Hong-Jun;Lee, Kyoung-Hoon;Woo, Kwan-Je;Koo, Man-Hoi;Joo, Jae-Hyun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.6
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    • pp.986-992
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    • 2011
  • In this paper, the characteristics of shock behavior of multi-layered panels under impact were studied. The panels consist of four different lightweight materials including al, al-foam, rubber and FRP in order to enhance their shock energy absorption. A commercial code, Ls-dyna was used to build the numerical model and study shock behavior based on the analysis of shock response spectrum and peak response acceleration. The reliability of the numerical model was estimated by its comparison with the experimental results acquired under the same impact conditions.

Experimental Study on the Shock Response of a Cylindrical Structure with the Bolted Joint (조인트를 가진 원통형 구조물의 충격 응답에 관한 실험적 연구)

  • Jeon, Ho-Chan;Song, Ohseop
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.5
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    • pp.581-589
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    • 2019
  • Guided missiles assembled with the bolted joint are subjected to various shock loading conditions while flying in the air and operating on the ground or platform. Especially, It is important to analyze the effect of the shock load on the structure because it affects the structure for a short duration time while its acceleration magnitude is quite large. In this study, mechanical shock tests on the structure with the bolted joint have been carried out to measure the acceleration changes of the structure against external shock loads by electrical exciter. Variation of dynamic characteristics of a structure with fastening methods and fastening forces has been investigated through Shock Response Spectrum analysis.

Comparison of Shock Isolation Characteristics using Rubber Washer (고무 와셔를 이용한 충격 절연 특성 비교)

  • Yang, Hong-Jun;Hong, Chang-Seob;Oh, Taek-Yul
    • Journal of the Korean Society of Mechanical Technology
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    • v.19 no.3
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    • pp.340-347
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    • 2017
  • The object of this study is to compare the shock isolation characteristics of the commercially available rubber washers due to the difference in a tightening torque and hardness. Drop impact test using a steel ball which can simulate the pyroshock acceleration was devised. The test results show that silicon had the highest shock isolation performances followed by urethane, nitrile showed the least performances. In addition, the test results show that the smaller a tightening torque and hardness, the shock isolation characteristics are improved. And this study propose an analysis method using the shock transmissibility function in order to minimize some uncertainty of the impact excitation in the shock response spectrum analysis.