• Title, Summary, Keyword: random vibration

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Maxima Response Spectrum for each Mechnical Vibration and its Application (기계적 진동에 대한 MRS 및 MRS의 응용)

  • 김재하;우호길
    • Journal of the Korea Institute of Military Science and Technology
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    • v.4 no.1
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    • pp.234-245
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    • 2001
  • This paper considers the Maximum Pesponse Spectrum for the random vibration, sinusoidal vibration, linear sweep vibration. The random vibration quality levels and the sinusoidal vibration quality level are compared using MRS. And the severity between the vibration test specification and real environments using Maximum Response Spectrum are also compared using it.

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Analysis of Fatigue Damage of the parts around the vehicle engine with Respect to Road surface conditions (도로 노면 조건을 고려한 차량 엔진 주변 부품의 피로손상도 분석)

  • Shin, Sung-Young;Kim, Chan-Jung;Lee, Bong-Hyeon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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Role of Distribution Function in Vibration Related Error of Strapdown INS in Random Vibration Test

  • Abdoli, A.;Taghavi, S.H.
    • International Journal of Aeronautical and Space Sciences
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    • v.15 no.3
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    • pp.302-308
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    • 2014
  • In this paper, a detailed investigation of the random vibration test is presented for strapdown inertial navigation systems (INS). The effect of the random vibration test has been studied from the point of view of navigation performance. The role of distribution functions and RMS value is represented to determine a feasible method to reject or reduce vibration related error in position and velocity estimation in inertial navigation. According to a survey conducted by the authors, this is the first time that the effect of the distribution function in vibration related error has been investigated in random vibration testing of INS. Recorded data of navigation grade INS is used in offline static navigation to examine the effect of different characteristics of random vibration tests on navigation error.

Random Vibration Analysis for Satellite Design (위성체 설계를 위한 랜덤 진동 해석)

  • Lee, Won-Beom;Kim, Gyeong-Won
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.102-107
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    • 2006
  • In this study, the dynamic environment of satellite consists of excessive vibration at low frequency and irregular acceleration transferred by launch vehicle structure. Excessive vibration at low frequency is generally approximated by a sinusoidal wave from 100Hz to 200Hz and primarily used to preliminary design The random vibration is created by structural vibration due to the combustion of launch vehicle, separation stage and external aerodynamic noise. these are transferred to the adapter structure between satellite and launch vehicle through the structure of launch vehicle. random vibration is being specified for acceptance tests, screening tests, and qualification tests, because it has been shown that random vibration more closely represents the true environments in which the electronic equipment must operate.

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Vibration Control of Flexible Dynamic System Exposed to Unknown Random Disturbance and Identification of the Random Disturbance (미지의 불규칙 외란에 노출된 유연 계의 진동제어 및 불규칙 외란의 규명)

  • 정근용;오용설;민성준;오경석;허훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.228-232
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    • 2004
  • This paper is to identify the position of random disturbance on flexible dynamic system, and the position of the piezo ceramic actuator 0 minimize tip response. Correlation of the output signals from each parts on flexible system is used to identify the position of random disturbance. Except the correlation with an output signal from the position of random disturbance, other correlations have time delay. This is a base idea to identify the position on this study.

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Comparison of Fatigue Damage of Linear Elastic System with Respect to Vibration Input Conditions (입력가진 조건에 따른 선형 시스템의 피로손상도 비교 평가)

  • Heo, Yun Seok;Kim, Chan-Jung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.6
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    • pp.437-443
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    • 2014
  • Vibration testing is conducted for evaluate the fatigue resistance of responsible system over excitation situations and two kinds of vibration profiles, harmonic or random, are widely used in engineering fields. Harmonic excitation profile is adequate for the rotating machinery that is primarily exposed to the orderly excited force subjected for a rotating speed; Random profile is suitable for the non-stationary vibration input, that is a ground excitation for example. Recently, the sine on random(SOR) testing method was sometimes considered to represent the real excitation conditions since the measured response signals of a target system, expecially for moving mobility, shows usually a mixture of them. So, it is important to understand the accumulated fatigue damage over different excitation patterns, harmonic and/or random, to determine the efficient vibration profile of a target system. A uniaxial vibration testing with a notched simple beam was introduced to evaluate the fatigue damage for different excitation profiles and the best choice of vibration profile was concluded from those comparison of calculated fatigue damages.

Comparison of fatigue damage of linear elastic system with respect to vibration input conditions (입력가진 조건에 따른 선형 시스템의 피로손상도 비교 평가)

  • Kim, Chan-Jung;Heo, Yun Seok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.340-345
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    • 2014
  • Vibration testing is conducted for evaluate the fatigue resistance of responsible system over excitation situations and two kinds of vibration profiles, harmonic or random, are widely used in engineering fields. Harmonic excitation profile is adequate for the rotating machinery that is primarily exposed to the orderly excited force subjected for a rotating speed; Random profile is suitable for the non-stationary vibration input, that is a ground excitation for example. Recently, the sine on random (SOR) testing method was sometimes considered to represent the real excitation conditions since the measured response signals of a target system, expecially for moving mobility, shows usually a mixture of them. So, it is important to understand the accumulated fatigue damage over different excitation patterns, harmonic and/or random, to determine the efficient vibration profile of a target system. A uniaxial vibration testing with a notched simple beam was introduced to evaluate the fatigue damage for different excitation profiles and the best choice of vibration profile was concluded from those comparison of calculated fatigue damages.

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Stochastic stability control analysis of an inclined stay cable under random and periodic support motion excitations

  • Ying, Z.G.;Ni, Y.Q.;Duan, Y.F.
    • Smart Structures and Systems
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    • v.23 no.6
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    • pp.641-651
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    • 2019
  • The stochastic stability control of the parameter-excited vibration of an inclined stay cable with multiple modes coupling under random and periodic combined support disturbances is studied by using the direct eigenvalue analysis approach based on the response moment stability, Floquet theorem, Fourier series and matrix eigenvalue analysis. The differential equation with time-varying parameters for the transverse vibration of the inclined cable with control under random and deterministic support disturbances is derived and converted into the randomly and deterministically parameter-excited multi-degree-of-freedom vibration equations. As the stochastic stability of the parameter-excited vibration is mainly determined by the characteristics of perturbation moment, the differential equation with only deterministic parameters for the perturbation second moment is derived based on the $It{\hat{o}}$ stochastic differential rule. The stochastically and deterministically parameter-excited vibration stability is then determined by the deterministic parameter-varying response moment stability. Based on the Floquet theorem, expanding the periodic parameters of the perturbation moment equation and the periodic component of the characteristic perturbation moment expression into the Fourier series yields the eigenvalue equation which determines the perturbation moment behavior. Thus the stochastic stability of the parameter-excited cable vibration under the random and periodic combined support disturbances is determined directly by the matrix eigenvalues. The direct eigenvalue analysis approach is applicable to the stochastic stability of the control cable with multiple modes coupling under various periodic and/or random support disturbances. Numerical results illustrate that the multiple cable modes need to be considered for the stochastic stability of the parameter-excited cable vibration under the random and periodic support disturbances, and the increase of the control damping rather than control stiffness can greatly enhance the stochastic stability of the parameter-excited cable vibration including the frequency width increase of the periodic disturbance and the critical value increase of the random disturbance amplitude.

Vibration Characteristics Analysis of the Communication Satellite Transponder Equipment (통신위성 중계기 부품의 진동특성 해석)

  • 김현수;이명규;박종흥;김성종;이영신
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.374-379
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    • 2001
  • The satellite electronic equipment is exposed to high level random vibration environment during the launch of spacecraft. The random vibration can cause damage of electronic equipment. Thus very careful consideration on the launch environment, especially for high level random vibration, is required in the design stage of transponder equipments of communication satellite. For the structural integrity of the communication satellite transponder equipment under qualification level random vibration, Finite Element analysis was carried out using the commercial code, MSC/Nastran and ANSYS and stress levels are presented. In order to validate the femodel, modal test was also performed and compared with numerical results.

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Optimum Design of Viscous Torsional Vibration Damper Using Random Tabu Search Method (Random Tabu 탐색법을 이용한 점성 비틀림 진동감쇠기의 최적설계)

  • 김유신;양보석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.301-306
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    • 1996
  • A torsional damper is generally used to reduce the torsional vibration which occurs at a crankshaft of a multi-cylinder high speed diesel engine. Vibration amplitude should be estimate by the appropriate simulation model to determine the optimum specifications of damper. In this paper a new method which was based on the random tabu search method(RTSM) would be introduced for the viscous damper design to optimize the damping performance. The result was ascertained by comparing with conventional rubber damper.

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