• Title/Summary/Keyword: Campbell Diagram

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Vibration Characteristic Study of Bevel Geared System Using Transfer Matrix Method (전달행렬법을 이용한 베벨기어 시스템의 진동특성연구)

  • Lee, Hyoung-Woo;Bae, Myung-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.4
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    • pp.118-126
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    • 2008
  • A new approach to the critical speed calculation of general multi-mesh gear chain system included bevel gear is presented. A transfer matrix mode! based on Hibner's branch method is developed and the natural properties of the branched rotor system are calculated with using the ${\lambda}$-matrix formulation. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the neighborhood of the operating speed, there are the two critical speeds amplifying the first mode and the eighth mode.

Rotordynamic Design and Stability Prediction of 100 Watts Micro Power System (100 Watts 급 초소형 파워 시스템의 회전체 동역학적 설계 및 안정성 예측)

  • Kwak, Hyun-Duck;Lee, Yong-Bok;Ryu, Keun;Kim, Chang-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.459-464
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    • 2003
  • The Roordynamic feasibility of Micro Power System supported by air foil bearings is investigated. The Micro Power System is new portable power source based on brayton cycle, which consists of compressor, turbine, generator, and combustion chamber. In this paper, the analysis of Rotordynamic characteristics of Micro Power System is performed based upon the bearing equilibrium position, Campbell diagram and stability. As a result, it is demonstrated that the air foil bearings could be adopted well to the Micro Power System. However, for more stable operation at target running speed, the damping characteristics of air foil bearing should be enhanced.

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Finite Element and Experimental Modal Analyses of Multiple Thin-Disked Flexible Spindle Systems (다중 박 원판을 갖는 유연 회전축계의 유한 요소 및 실험적 모드 해석)

  • 임승철;제인주
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.1029-1035
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    • 1999
  • This paper relates to the flexural vibration analysis of slender spindle systems with multiple thin disks, supported by the ball bearings by means of the finite element method. Each system component is analytically modeled taking into account its flexibility and also the centrifugal effect especially for the disk. In order to show the rapid convergence rate and accuracy of the proposed approach, an experimental set-up is built to be versatile. In two distinct cases, its natural modes are numerically computed using only a small number of total element meshes as the shaft rotational speed is varied, and verified through experimental frequency response function obtained by the impact test.

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Optimization and dynamic characteristics of the hybrid type vacuum pump (하이브리드 타입 진공펌프의 동특성 및 최적화)

  • Kim, Yong-Hwi;Lee, Jong-Myeong;Ahn, Byeong-Hyun;Ha, Jeong-Min;Choi, Byeong-Keun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.306-310
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    • 2014
  • The purpose of this study is the stability evaluation of a vacuum pump through modal test and rotor dynamics. Eigenvalue was solved by the finite-element method(FEM) using 2D and 3D models, then the modal test result was compared with the FEM result. According to the comparison, the analysis result using the 2D was more accurate than the 3D model. Therefore, rotor dynamics was performed by the 2D model. Campbell diagram and root-locus maps, which were calculated by complex-eigenvalue analysis, were used to evaluate the stability of the rotors of the vacuum pump. And displacement solved by unbalance response analysis was compared with the minimum clearance between two rotors of the vacuum pump. Thus, the vacuum pump is assumed operated under steady state through the evaluation of the rotor dynamics.

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Natural Vibration and Failure Trouble in LP Stage Blades of Nuclear Power Turbine (원전 터빈 저압단 블레이드의 절손사고와 진동특성)

  • Koo, Jae-Raeyang;Lee, Woo-Kwang;Cho, Cheul-Whan;Kim, Yeon-Whan;Kang, Byeong-Yeon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1040-1043
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    • 2006
  • Every mechanical system has a series of natural frequencies at which it will vibrate and to which it will respond if an external stimulus or excitation at this frequency is applied. Vibration is not of itself dangerous, and is always anticipated in an operating unit. However, if the frequency of operation is coincidental with one of the natural frequency of the blade system or the blade has a natural frequency near coincide with the exciting stimulus, then the amplitude of vibration of the blade may increase to the destructive damage can result. In this paper We investigated damage of blade when turbine operated.

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A Study on Dynamic Characteristics by Gearbox of High-speed Pump (고속 펌프용 증속기의 동특성에 관한 연구)

  • Lee, Dong-Hwan;Lee, Hyeong-U
    • 연구논문집
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    • s.31
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    • pp.65-75
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    • 2001
  • A dynamic model of pump having one step gearbox and two step gearbox is developed by the lumped parameter method. The model accounts for shafts, ball bearings and journal bearings flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Excitation forces of pump having one step gearbox and two step gearbox are considered as the mass unbalance of the rotors and gear transmission error which comes from the modified tooth surface. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered, shows that there are no critical speeds at the operating speeds. One step and two step gearboxes are manufactured and are estimated for vibration/noise, lubrication and performance.

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Dynamic Analysis of FCEV Turbo Blower (연료전지 자동차용 터보 블로워의 동특성 해석)

  • Yook, J.Y.;Yang, H.S.;Lee, C.H.;Cho, K.S.;Kim, K.I.;Kwon, H.R.;Park, Y.S.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.7
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    • pp.591-598
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    • 2011
  • This paper presents dynamic analysis of FCEV(fuel cell electric vehicle) turbo blower. To analyze the dynamic characteristics of turbo blower, FEA(finite element analysis) and experimental test are performed. Evaluations of stress safety for rotor sleeve and impeller due to rotational force and shrink fit are performed. Rotor dynamic analysis is conducted by Campbell diagram and structure vibration analyses are performed using FEA and experimental test. Through these results, noise sources of turbo blower are verified.

Analytical Evaluation of Rotor Dynamic Characteristic of Roots Type Vacuum Pump (루츠타입 진공펌프 동특성의 해석적 평가)

  • Lee, Jong-Myeong;Kim, Yong-Hwi;Ha, Jeong-Min;Gu, Dong-Sik;Choi, Byeong-Keun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.12
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    • pp.1112-1119
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    • 2011
  • The goal of this study is the stability evaluation of a vacuum pump through modal test and rotor dynamics. Roots type vacuum pump, which is a dry vacuum pump, is necessary for the manufacturing process of the semiconductor and the display. Eigenvalue was solved by the finite-element method(FEM) using 2D and 3D models, then the modal test result was compared with the FEM result. According to the comparison, the analysis result using the 2D was more accurate than the 3D model. Therefore, rotor dynamics was performed by the 2D model. Campbell diagram and root-locus maps, which were calculated by complex-eigenvalue analysis, were used to evaluate the stability of the rotors of the vacuum pump. And displacement solved by unbalance response analysis was compared with the minimum clearance between two rotors of the vacuum pump. Thus, the vacuum pump is assumed operated under steady state through the evaluation of the rotor dynamics.

Operational Vibration Experiment and Analysis of a Small Vertical-Axis Wind Turbine Considering the Effect of a Tower Stiffness (타워강성 효과를 고려한 소형 수직축 풍력발전기 운전 진동실험 및 해석)

  • Choo, Heon-Ho;Sim, Jae-Park;Oh, Min-Woo;Kim, Dong-Hyun
    • The KSFM Journal of Fluid Machinery
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    • v.16 no.3
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    • pp.5-9
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    • 2013
  • In this study, operational vibration experiment and analysis have been conducted for the 4-blade small vertical-axis wind turbine (VAWT) including the effect of tower elastic behavior. Computational structural dynamics analysis method is applied to obtain Campbell diagram for the VAWT with elastic tower. An open type wind-tunnel is used to change and keep the wind velocity during the ground test. Equivalent elastic tower is used to support the VAWT so that the effect of elastic stiffness of the tower can be considered in the present vibration experiment. Various excitation conditions with wind loads are considered and the dominant operating vibration phenomena are physically investigated in detail.

Running Bucket Vibration Test of Steam Turbines (증기 터빈 버킷의 회전 진동 시험)

  • 박종포;신언탁;김호종
    • Journal of KSNVE
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    • v.8 no.2
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    • pp.331-335
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    • 1998
  • A design modification was made on the 9-th stage wheel dovetail of a high-intermediate pressure (HIP) turbine rotor for a fossil power plant that necessitates the use of new long-shank buckets for the row. A bucket vibration test is necessary to verify that the new 9-th stage buckets have adequate frequency margin from a nozzle passing frequency when running at speed. A finite element analysis (FEA) has been performed using a commercial S/W to approximately estimate bucket natural frequencies, and thus to help the vibration test. A row of the new buckets has assembled on the HIP rotor for the vibration tests using dynamic balancing facilities. The tests have been done during deceleration run with air excitation. The test results are compared with the calculation using our empirical formula, and show that the modified design meets the frequency-margin requirements.

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