• 제목/요약/키워드: Primary Vibration System

검색결과 189건 처리시간 0.021초

감쇠진동계에 부착된 복합동흡진기의 효과에 관한 연구 (A Study on the Effects of Dual Dynamic Vibration Absorber for Damped Vibration System)

  • 안찬우;최석창;김동영
    • 소음진동
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    • 제7권6호
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    • pp.1039-1048
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    • 1997
  • This paper describes the effects of dual dynamic vibration absorbers attached to a primary vibration system with damping. The efficiency of dual dynamic vibration absorbers was investigated with the height of amplitude ratio at the resonance frequency ratio of the damped vibration system according to mass ratio, natural frequency ratio and damping ratio. The variation of amplitude ratio related to frequency ratio of primary vibration system is verified experimentally and theoretically according to dual dynamic vibration systems using computer program designed to find mutual relationship between two absorbers.

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기반의 조화운동을 받는 감쇠선형진동계의 최적 복합동흡진기에 관한 연구 (A Study on Optimal Multi-dynamic Absorber of Damped Linear Vibration System under the Harmonic Motion of the Base)

  • 안찬우;김동영;홍도관
    • 소음진동
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    • 제10권2호
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    • pp.325-330
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    • 2000
  • A dynamic absorber is used to protect the primary vibration system under the steady-state harmonic disturbance. In a number of cases it appears expedient to install several absorbers of smaller masses instead of one. This may be due to the need of distribute the absorber's response along the construction, restrictions on the absorber's installation. So, we studied characteristics of the primary vibration system for the optimal natural frequency ratio and the optimal damping ratio of serial multi-dynamic absorber. Also we obtained the optimum values of the serial multi-dynamic absorber parameters using computer simulation for the damped primary vibration system. In designing multi-dynamic absorber, we presented for the optimal natural frequency and the optimal damping ratio of multi-dynamic absorbers.

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Active Nonlinear Vibration Absorber for a Nonlinear System with a Time Delay Acceleration Feedback under the Internal Resonance, Subharmonic, Superharmonic and Principal Parametric Resonance Conditions Simultaneously

  • Mohanty, S;Dwivedy, SK
    • 항공우주시스템공학회지
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    • 제13권5호
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    • pp.9-15
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    • 2019
  • In this paper, dynamic analysis of a nonlinear active vibration absorber is conducted with a time delay acceleration feedback to suppress the vibration of a nonlinear single degree of freedom primary system. The primary system consisting of linear and nonlinear cubic springs, mass, and damper is subjected to the multi-harmonic hard excitation with a parametric excitation. It is proposed to reduce the vibration of the primary system and the absorber by using a lead zirconate titanate (PZT) stack actuator in series with a spring in the absorber which configures as an active vibration absorber. The method of multiple scales (MMS) is used to obtain the approximate solution of the system under the internal resonance, subharmonic, superharmonic, and principal parametric resonance conditions simultaneously. Frequency and time responses of the system are investigated considering a delay in the feedback for the various parameters of the absorber configuration and controlling force.

감쇠진동계에 부착된 코일스프링과 오일댐퍼로 구성된 동흡진기

  • 최석창;안찬우;박일수;이희범
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 춘계학술대회 논문집
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    • pp.289-293
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    • 1996
  • Vibration absorber is used to protect the primary system from steady-state harmonic disturbance. By attaching the absorber to the primary system which is modeled as a SDOF system, the new system becomes two DOF system. Depending on the driving frequency on the original system, the absorber needs to be carefully tuned, that is, to choose adequate value of the absorber mass and stiffness, so that the motion of the original mass is a minimum. This paper presents the effects of resonance frequency ratio and of vibration absorber with oil damper and coil spring for linear damped primary systems.

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Robust design of liquid column vibration absorber in seismic vibration mitigation considering random system parameter

  • Debbarma, Rama;Chakraborty, Subrata
    • Structural Engineering and Mechanics
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    • 제53권6호
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    • pp.1127-1141
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    • 2015
  • The optimum design of liquid column dampers in seismic vibration control considering system parameter uncertainty is usually performed by minimizing the unconditional response of a structure without any consideration to the variation of damper performance due to uncertainty. However, the system so designed may be sensitive to the variations of input system parameters due to uncertainty. The present study is concerned with robust design optimization (RDO) of liquid column vibration absorber (LCVA) considering random system parameters characterizing the primary structure and ground motion model. The RDO is obtained by minimizing the weighted sum of the mean value of the root mean square displacement of the primary structure as well as its standard deviation. A numerical study elucidates the importance of the RDO procedure for design of LCVA system by comparing the RDO results with the results obtained by the conventional stochastic structural optimization procedure and the unconditional response based optimization.

감쇠진동계에 부착된 코일스프링과 오일댐퍼로 구성된 동흡진기 (Dynamic Vibration Absorber Having Coil Springs and Oil Damper for a Damped Vibration System)

  • Ahn, C.W.;Park, S.C.;Lee, H.B.
    • 한국정밀공학회지
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    • 제13권12호
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    • pp.129-135
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    • 1996
  • This paper presents the effectiveness of the dynamic vibration absorber consisting of a single mass, coil springs and oil damper on the resonance freauency ratio and amplitude ratio for damped linear systems, that is, primary vibration system with damping. The effects of the dynamic vibration absorber are investigated numerically and experimentally for values of mass ratio, natural frequency ratio, and damping ratio. The experimental results show good agreement with calculated ones. As a result, the characteristics shown by the present work are useful in optimal tuning the dynamic vibration absorber in practice.

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Experimental study on vibration serviceability of cold-formed thin-walled steel floor

  • Bin Chen;Liang Cao;Faming Lu;Y. Frank Chen
    • Steel and Composite Structures
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    • 제46권4호
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    • pp.577-589
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    • 2023
  • In this study, on-site testing was carried out to investigate the vibration performance of a cold-formed thin-walled steel floor system. Ambient vibration, walking excitation (single and double persons), and impulsive excitation (heel-drop and jumping) were considered to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes) and vertical acceleration response. Meanwhile, to discuss the influence of cement fiberboard on structural vibration, the primary vibration parameters were compared between the systems with and without the installation of cement fiberboard. Based on the experimental analysis, the cold-formed thin-walled steel floor possesses high frequency (> 10 Hz) and damping (> 2%); the installed cement fiberboard mainly increases the mass of floor system without effectively increasing the floor stiffness and may reduce the effects of primary vibration parameters on acceleration response; and the human-structure interaction should be considered when analyzing the vibration serviceability. The comparison of the experimental results with those in the AISC Design Guide indicates that the cold-formed thin-walled steel floor exhibits acceptable vibration serviceability. A crest factor 𝛽rp (ratio of peak to root-mean-square accelerations) is proposed to determine the root-mean-square acceleration for convenience.

점성댐퍼를 갖는 엔진 축계의 안정성 해석 및 비선형 비틀림강제진동 (A Study on the Stability Analysis and Non-linear Forced Torsional Vibration for the Dngine Shafting System with Viscous Damper)

  • 박용남;하창우;김의간;전효중
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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    • pp.282-287
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    • 1996
  • The non-linear torsional vibrations of the propulsion shafting system with viscous damper are considered. The motion is modeled by non-linear differential equations of second order. the equivalent system is modeled by two mass softening system with Duffing's oscillator. The steady state response of a equivalent system is analyzed for primary resonance only. Harmonic balance method as a non-linear vibration analysis technique is used. Jump phenomena are explained. The primary unstable region obtained by the Mathieu equation is investigated. Both theoretical and measured results of the propulsion shafting system are compared with and evaluated. As a result of comparisons with both data, it was confirmed that Duffing's oscillator can be used as a analysis method in the modeling of the propulsion shafting system attached viscous damper with non-linear stiffness.

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불규칙가진의 반발계수 진동-충격 시스템의 수치해석 (Numerical Analysis of Randomly Driven Vibro-Impact System With a Coefficient of Restitution Contact Mechanism)

  • 이창희
    • 소음진동
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    • 제8권3호
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    • pp.513-523
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    • 1998
  • Impact response of a vibro-impact system and its contact mechanism was studied. The vibro-impact system is composed of a small secondary system is constrained to move along a slot of fixed length in a large primary system. The contact mechanism is characterized by its coefficient of restitution. Numerical simulation analysis has been used to determine the time-history and the impact statistics of the primary and secondary systems. Input excitation of the primary system was random, and the responses obtained were the velocities of the primary and secondary system, the closing velocity in time axis and the duration time between impacts. The validity of the numerical simulation method was checked by comparing the results with those obtained by other researchers analytically. It is shown that the results obtained by the nemerical simulation analysis showed a good agreement with those for the analytical method.

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이동하중을 받는 보와 가동 기초 위에 설치된 계에의 동흡진기의 이용 (Usage of Dynamic Vibration Absorbers for a Beam Subjected to Moving Forces and for a System Mounted on a Moving Base)

  • 이건명;변재현
    • 한국기계가공학회지
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    • 제14권6호
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    • pp.27-34
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    • 2015
  • Dynamic vibration absorbers are widely used in machinery, buildings, and structures, including bridges. Two cases of their usage are considered in this paper. One is a simply supported beam subjected to either a moving force or a sequence of moving forces, which simulates a train-bridge interaction problem. The other is a case where a primary system is mounted on a base that is not grounded and is excited by an external force. The conditions that the dynamic vibration absorbers must meet in these cases are found and compared to those for usual cases where bases of primary systems are grounded.