• Title/Summary/Keyword: Vibration Localization

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Vibration Localization of Open Loop Repeated Structures (개방형 반복구조물의 진동국부화)

  • 하동진;유홍희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.489-494
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    • 2003
  • Vibration localization characteristics of open loop repeated structures with mistuning are investigated in this paper. Mistuning of a periodic structure often creates significant non-uniformity in vibration responses. As a result of the localization, critical fatigue problems often occur in repeated structures. Therefore, it is of great importance to predict the vibration response of the mistuned repeated structures accurately. In this paper, a simplified model for the open-loop repeated structure is introduced and dimensionless parameters which influence the localization characteristics are identified. The effects of the parameters on the localization characteristics are investigated through numerical study.

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Statistical Approach to Analyze Vibration Localization Phenomena in Periodic Structural Systems

  • Shin Sang Ha;Lee Se Jung;Yoo Hong Hee
    • Journal of Mechanical Science and Technology
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    • v.19 no.7
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    • pp.1405-1413
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    • 2005
  • Malfunctions or critical fatigue problems often occur in mistuned periodic structural systems since their vibration responses may become much larger than those of perfectly tuned periodic systems. These are called vibration localization phenomena and it is of great importance to accurately predict the localization phenomena for safe and reliable designs of the periodic structural systems. In this study, a simple discrete system which represents periodic structural systems is employed to analyze the vibration localization phenomena. The statistical effects of mistuning, stiffness coupling, and damping on the vibration localization phenomena are investigated through Monte Carlo simulation. It is found that the probability of vibration localization was significantly influenced by the statistical properties except the standard deviation of coupling stiffness.

Vibration Localization due to Mistuned Coupling Effects Among Repeated Structures (반복 구조간 연성 효과의 불균일성에 의한 진동 국부화)

  • Kang, Min-Kyoo;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.12
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    • pp.994-1000
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    • 2002
  • In periodically repeated cyclic structures, small property irregularity of their substructures often causes significant difference in their dynamic responses. which results in unpredicted premature failures. The small irregularity and the resulting phenomenon are called the mistuning and the vibration localization. respectively. In this paper, the vibration localization phenomena due to mistuned coupling effects are investigated. To effectively achieve the objective, a simple coupled multi-pendulum system Is employed. The results show that if there exists some coupling stiffness irregularity, vibration localization may occur and becomes more predominant as the number of substructures increases.

Comparison study on mode and response localization (모드국부화와 응답국부화의 비교연구)

  • 하동진;유홍희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.704-709
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    • 2003
  • Vibration localization characteristics of repeated mistuned structures are investigated by two ways. The mistuning often creates significant response discrepancies among subcomponents of the repeated structures. As a result of the discrepancies, critical fatigue problems often occur in repeated structures. Therefore, it is of great importance to predict the vibration response of the mistuned repeated structures accurately. In this paper, a simplified model is employed and dimensionless parameters that influence the localization characteristics are first identified. Through the parameter study, the two localization phenomena are investigated and compared.

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Mode Localization Phenomenon in Non-Periodic Multispan Beams (불규칙 다경간 보의 모우드 편재현상에 관한 연구)

  • 김동옥;이인원
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.211-216
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    • 1997
  • The mode localization phenomenon in non-periodic multispan beam is theoretically investigated. When localization occurs, the free vibration amplitude of a normal mode becomes confined to a local region of the structure. It is well known that the weakly coupled periodic structures are sensitive to certain types of periodicity-breaking disorder, resulting in the mode localization. The results of this study indicate that the mode localization occurs also in nonperiodic structures and the degrees of mode localization of some modes are very sensitive to system parameters. Free vibration analysis of simply supported two-span beams of arbitrary span lengths is performed. Degrees of mode localization and their sensitivities to system parameters are appraised by considering the characteristic graph and the structural line defined in this study first.

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Vibration Localization of Open Loop Repeated Structures (개방형 반복구조물의 진동국부화)

  • Ha, Dong-Jin;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.12
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    • pp.911-917
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    • 2003
  • Vibration localization characteristics of open loop repeated mistuned structures are investigated. The mistuning often creates significant response discrepancies among subcomponents of the repeated structures. As a result of the discrepancies, critical fatigue problems often occur in repeated structures. Therefore. it is of great importance to predict the vibration response of the mistuned repeated structures accurately in this Paper, a simplified model for an open-loop repeated structure is introduced and dimensionless parameters that influence the localization characteristics are identified. The effects of the parameters on the localization characteristics are investigated through numerical study.

Comparison Study on Mode and Response Localizations (모드 국부화와 응답 국부화의 비교연구)

  • 하동진;유홍희
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.6
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    • pp.478-485
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    • 2004
  • Vibration localization characteristics of mistuned repeated structures are investigated. The mistuning often creates significant response discrepancies among subcomponents of a repeated structure. As the result of the discrepancies, critical fatigue often occurs in a repeated structure. Therefore, it is of great importance to predict the vibration response of the mistuned repeated structures accurately. In this paper, a simplified model is employed and dimensionless parameters that influence the localization characteristics are identified. Through parameter study, two localization phenomena are investigated and compared.

Vibration Localization of a Periodic Structure Undertaking External Force (외력을 받는 주기적 구조물의 진동 국부화)

  • Kim, Jae-Young;Yoo, Hong-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.543-548
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    • 2000
  • Vibration localization of a periodic structure with mistuning is presented in this paper. Mistuning in periodic structures can lead to an increase of the forced response which is much larger than those of perfectly tuned assembly. Thus, mistuning has a critical impact on high cycle fatigue in structures, and it is of great importance to predict the mistuned forced response in efficient manner. In this paper, forced response of a coupled pendulum is investigated to identify localization effects of periodic structures. The effects of mistuning and damping on the maximum forced response are examined. It is seen that in certain condition of mistuning and coupling, strong localization occurs and this can be significant under weak damping.

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The Effects of the Stiffness Mistuning and the Excitation Force Phase Difference on the Vibration Localization of Cyclic Structures (순환 구조물의 진동 국부화에 미치는 강성 불균일 및 가진력 위상차의 효과)

  • Kang, Min-Kyoo;Yoo, Hong-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.8
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    • pp.1347-1352
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    • 2003
  • In periodic cyclic structures, small property irregularity of their substructured often causes significant difference in their dynamic responses, which results in unpredicted premature failures. The small irregularity and the resulting phenomenon are called the mistuning and the vibration localization, respectively. In this paper a simple coupled multi-pendulum system is employed to investigate the effects of the stiffness mistuning and the phase difference in excitation force on the vibration localization of periodic cyclic structures.