• Title/Summary/Keyword: Vibration Reduction Method

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Torsional Vibration Analysis of a Multi-Stage Reduction Gear System (다단 감속치차계의 비틀림진동 해석)

  • 이동환;김영철;최상규;이안성
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.307-312
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    • 1996
  • A torsional vibration analysis of a multi-stage reduction gear box connected to a gas turbine system is presented. For a free vibration analysis the Modified Hibner Branch Method, so called "Blank Matrix Method", and the .lambda.-Matrix Method are used in the modeling and the eigenvalue solution, respectively. Also, a short circuit forced analysis of the system is performed, utilizing the energy method modeling. It is shown that the results of the free vibration analysis have the same tendency as those of the short circuit analysis. analysis.

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A Method of Effective Vibration Reduction for Positioning Systems Undergoing Frequent Short-distance Movement (단거리 이동을 반복하는 위치결정장치를 위한 효율적인 진동저감 방법)

  • Hong, Seong-Wook;Bae, Gyu-Hyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.3
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    • pp.421-428
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    • 2013
  • The current vibration reduction methods for positioning systems lead to either complicated motion or the need for additional hardware when the positioning systems carry out frequent short-distance movements. This paper proposes a simple yet efficient vibration reduction method for positioning systems subjected to frequent short-distance movements. The essence of the proposed method is the trapezoidal or triangular velocity profiles, whose acceleration/deceleration rates are designed to be related to the natural frequency of concern. The combined use of the proposed method and the input shaping method is also proposed for the possible application to multi-mode systems. Experiments are performed to validate the proposed method. The simulation and experiments prove that the proposed method is of great use for residual vibration reduction in positioning systems subjected to frequent short-distance movement.

A Study on Evaluation of Vibration Reduction Effect of Concrete tracks (콘크리트 궤도 유형별 진동성능평가에 대한 연구)

  • Yang, Shin-Chu;Kim, Eun;Kang, Yun-Suk;Um, Ju-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.911-916
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    • 2002
  • One of important roles of concrete track is to reduce vibration transmitting to subgrade. In this paper, a numerical method for evaluating the effects of vibration reduction of concrete track is presented. Using the method, high frequency dynamic analyses and track-tunnel-soil interaction analyses are carried out for three types of concrete track in order to investigate the vibration reduction effects compared with normal ballast track.

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Vibration Reduction of Chip-Mount System (칩 마운트 시스템의 진동 경감)

  • 임경화;장헌탁
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.8
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    • pp.331-337
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    • 2001
  • The purpose of this study is to analyze the principal causes of vibration problem and find out the method of vibration reduction in a chip-mount system. The principal causes are investigated through measurements of vibration spectrum and model parameters. Modal parameters are obtained by using an experimental model test. Based on the model parameters from experiments. a model of finite element method is formulated. The model presents effective redesign of increasing the natural frequencies in order to reduce the vibration of a chip-mount system. Further, through computer simulation for the behavior of head to be main vibration source, the best acceleration pattern of head movement can be verified to achieve effective head-positioning and reduce the vibration due to head movement.

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Reduction of Railway-induced Vibration using In-filled Trenches with Pipes

  • Hasheminezhad, Araz
    • International Journal of Railway
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    • v.7 no.1
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    • pp.16-23
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    • 2014
  • Reduction in railway-induced vibrations in urban areas is a very challenging task in railway transportation. Many mitigation measures can be considered and applied. Among these, a little attention has been paid to trenches. In this study, a numerical investigation on the effectiveness of in-filled trenches with pipes in reducing railway vibrations due to passing trains is presented. Particularly, a series of two-dimensional dynamic analysis was performed to model the behavior of ballasted railway track under harmonic load with ABAQUS software as a Finite Element method. In so doing, two types of in-filled trenches with pipes with steel and concrete materials have been investigated in this paper. In addition, effectiveness of pipes made of steel and concrete, filled with loose sand and clay in railway-induced vibration reduction has been assessed. The results point out that using in-filled trench with pipes does not effective a lot on railway-induced vibration reduction in comparison to other railway-induced vibration reduction methods. However, in-filled trenches with steel pipes are much more effective than in-filled trenches with concrete pipes. Moreover, filling pipes with loose sand and clay does not have any effect on vibration reduction efficiency of these in-filled trenches.

Straight-line Path Error Reduction for the End of a Flexible Beam Deploying from a Rotating Rigid Hub (회전하는 강체허브에서 전개하는 보 끝단의 직선궤적오차 저감)

  • Kim, Byeongjin;Kim, Hyungrae;Chung, Jintai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.11
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    • pp.898-906
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    • 2014
  • This paper presents a reduction method for a straight-line path error of a flexible beam deploying from a rotating rigid hub. Previous studies discussed about only vibration phenomena of flexible beams deploying from rotating hubs; however, this study investigates a vibration reduction of a rotating beam with variable length. The equation of motion and associated boundary conditions are derived for a flexible beam deploying from a rotating rigid hub, and then they are transformed to a variational equation. By applying the Galerkin method, the discretized equations are obtained from the variational equation. Based on the discretized equations, the dynamic responses of a rotating/deploying beam are analyzed when the beam end has a straight line motion. A reduction method for the trajectory error is proposed, using the average length of a rotating/deploying beam. It is shown that the proposed method is able to reduce the residual vibration of a rotating/deploying beam.

Shape Design of Frame Structures for Vibration Suppression and Weight Reduction

  • Hase, Miyahito;Ikeda, Masao
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2246-2251
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    • 2003
  • This paper proposes shape design of frame structures for vibration suppression and weight reduction. The $H_{\infty}$ norm of the transfer function from disturbance sources to the output points where vibration should be suppressed, is adopted as the performance index to represent the magnitude of vibration transfer. The design parameters are the node positions of the frame structure, on which constraints are imposed so that the structure achieves given tasks. For computation of Pareto optimal solutions to the two-objective design problem, a number of linear combinations of the $H_{\infty}$ norm and the total weight of the structure are considered and minimized. For minimization of the scalared objective function, a Lagrange function is defined by the objective function and the imposed constraints on the design parameters. The solution for which the Lagrange function satisfies the Karush-Kuhn-Tucker condition, is searched by the sequential quadratic programming (SQP) method. Numerical examples are presented to demonstrate the effectiveness of the proposed design method.

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Vibration Analysis Method for Railway Structure with Floating Slab (방진궤도가 부설된 역사의 진동해석 기법)

  • 양신추;김태욱;강윤석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.561-566
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    • 2003
  • In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under floating slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effects of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

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Development of Evaluation Method of Vibration-Reduction Efficiency in Slab Track (슬래브궤도의 방진효율성 평가기법 개발)

  • 양신추;강윤석;김만철;이종득
    • Proceedings of the KSR Conference
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    • 1999.11a
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    • pp.463-470
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    • 1999
  • In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effect of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

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A Case of Blasting Vibration Reduction in the Tunnel Construction under a Residential Area (주거지역 터널공사에서의 발파진동 저감사례)

  • Kang, Jin-Ook;Lee, Hyun-Koo;Lee, Myong-Choul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.175-180
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    • 2007
  • This paper presents a case study on blasting vibration reduction in NATM(New Australian Tunnelling Method) tunnel construction carried out under a congested residential area. In NATM tunnel constructions, blasting is an essential process, thus vibration phenomenon is inevitable. Therefore, the vibration reduction was tried to avoid expected complaints from the public living in the area. Test blastings were performed to get the constants for an estimation formula of vibration velocity. Then the influence area was approximated using the estimation formula, and construction methods for the vibration reduction were sought based on the results.

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