• Title/Summary/Keyword: dynamic eccentricity

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A Study on the Designs of John Galliano (존 갈리아노(John Galliano)의 디자인 연구(硏究))

  • Park, Hye-Won
    • Journal of Fashion Business
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    • v.3 no.2
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    • pp.19-29
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    • 1999
  • The purpose of this study is for consideration of John Galliano's fashion design works. Galliano, young British designer, became the chief designer of Givenchy in 1995 and of Christian Dior in 1996. Through fashion information from WWD, High Fashion, Mode et Mode, Collezioni, Vogue, Internet sites and video tapes from 1995 to 1999, his works were concerned for this study. The results are as followed; First, we can find dynamics in Galliano's works. The dynamic mood came from his study about historic costume. Second, new beauty from dismantling and reconstruction was expressed on his designs. Third, his experimental creativities were based on fashion business. Therefore Galliano's eccentricity signify the Maximalism against the Minimalism which dominated the end of 20th century. So we can find a clue to new millenium in fashion world in his designs.

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Transient Dynamic Analysis of a Dynamci Eccentric Rotor with Unbalanced Magnetic Forces in BLDC Motors (BLDC 전동기의 동적 편심 및 전자기적 불평형력을 고려한 편심 회전자의 과도 동적 해석)

  • 김태종;황상문;박노길
    • Journal of KSNVE
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    • v.10 no.3
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    • pp.401-409
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    • 2000
  • Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins through the motor air-gap. When a relative misalignment of rotor in the air-gap center exists on the assemblage it is considered to influence the motor system characteristics, depending on the degree of misalignment. The rotor-motor system used in a washing machine is modeled using FE-TM and a magnetic force of BLDC motor with radial rotor eccentricity is analyzed. And the transient whirl responses of a rotor system with relative misalignment in the motor air-gap are investigated considering mechanical origins and magnetic effects. Results show that rotor misalignment in the air-gap affect the vibration of the rotor-motor system.

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Efffects of Synchronous Vibration of Bearing on Stability of Externally Pressurized Air Journal Bearing (베어링의 동기 진동이 외부 가압 공기 저어널 베어링의 안정성에 미치는 영향)

  • Lee, Jeong-Bae;Kim, Kyung-Woong
    • Tribology and Lubricants
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    • v.13 no.1
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    • pp.28-33
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    • 1997
  • Results of theoretical investigations of the stability characteristics of externally pressurized air journal bearing, of which bearing is synchronously vibrate with respect to rotor, are presented. Linearized perturbation method is used to get the dynamic coefficients of air bearing, and the Routh-Hurwitz criterion is used to obtain stability map. The stability characteristics operating at zero steady-state eccentricity is investigated of various phase difference of bearing to rotor. It is shown that stability of air bearing is greatly influenced by synchronous motion of bearing, there exists optimum phase difference which gives maximum stability threshold.

Behavior Analysis of Double Lip Seal with Interference (간섭량에 따른 이중 립 실의 거동 해석)

  • Jung, H.G.;Yoo, J.C.;Park, T.J.
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1576-1580
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    • 2007
  • Typical lip seals are widely used as sealing mechanism of rotary and reciprocating shaft. Double lip seal has comparatively high stiffness and dynamic radial eccentricity. Usually material of these seals is made of elastomer and nonlinear finite element analysis is required to analyze behaviour of this material because Young's modulus is varied with working load. In this paper, MSC MARC/MENTAT is used for nonlinear analysis of double lip seal with pressure variation and interference. The contact normal force of double lip seal between lip and shaft is analyzed to reduce power loss when shaft rotates.

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Acoustic Noise Reduction of A SRM for Fan in Air conditioner (에어컨 팬 모터용 SRM의 소음 저감)

  • Lee, Dong-Il;Shin, Hyoun-Jeong;Lim, Jun-Young;Han, Seung-Do
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.816-821
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    • 2002
  • It is getting more important that energy efficiency and manufacturing cost of the electric motor in appliance. The SRM has been alternative choice. But acoustic noise and harshness in this motor was widely known. So this paper had been studied on the noise reduction of a SRM in air conditioner. This works include some parameters regarding to blown noise sources like a reluctance torque ripple, air gap eccentricity, Especially, it was focused on dynamic characteristics of the system based on mechanical viewpoint. It came to successful results. Besides, this gave us a validity of phase excitation in experimental measurements.

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Cracked rotor diagnosis by means of frequency spectrum and artificial neural networks

  • Munoz-Abella, B.;Ruiz-Fuentes, A.;Rubio, P.;Montero, L.;Rubio, L.
    • Smart Structures and Systems
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    • v.25 no.4
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    • pp.459-469
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    • 2020
  • The presence of cracks in mechanical components is a very important problem that, if it is not detected on time, can lead to high economic costs and serious personal injuries. This work presents a methodology focused on identifying cracks in unbalanced rotors, which are some of the most frequent mechanical elements in industry. The proposed method is based on Artificial Neural Networks that give a solution to the presented inverse problem. They allow to estimate unknown crack parameters, specifically, the crack depth and the eccentricity angle, depending on the dynamic behavior of the rotor. The necessary data to train the developed Artificial Neural Network have been obtained from the frequency spectrum of the displacements of the well- known cracked Jeffcott rotor model, which takes into account the crack breathing mechanism during a shaft rotation. The proposed method is applicable to any rotating machine and it could contribute to establish adequate maintenance plans.

3 Dimensional Modeling and Sensitivity Analysis for Vibration Reduction of the Spin-Coater System

  • Park, Jin-Bae;Han, Chang-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.170.2-170
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    • 2001
  • In this paper, the dynamic system modeling and the state sensitivity analysis of the spin-coater system for the reduction of the vibration are proposed. In the respect of modeling, the spin-coater system is composed of components of servomotor, belt, spindle, and a supported base. Each component is defined and combined modeling is derived to 3dimensional equations. Verification of modeling is verified by experimental values of actual system in the frequency domain. By direct differentiation the constraint equations with respect to kinematic design variables, such as eccentricity of spindle, moment of inertia, torsional stiffness and damping of supported base, sensitivity equations are derived to the verified state equations. Sensitivity of design variables could be used for vibration reduction and natural frequency shift in the frequency domain. Finally, dominant design variables ...

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Performance Evaluation of KHSR Bridges Using 2-D Train/Track/Bridge Interaction Analysis Method (2차원 상호작용 해석법을 이용한 한국고속철도 교량의 성능평가)

  • 김만철;심성택;이희연
    • Proceedings of the KSR Conference
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    • 2000.11a
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    • pp.366-373
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    • 2000
  • This paper represents the results carried out to determine the dynamic response characteristics of Korea High Speed Rail(KHSR) bridges. The responses of the KHSR bridges subjected to the moving train loading are obtained through the simplified method for the 2-dimensional train/track/bridge interaction analysis in which the eccentricity of axle loads and the effect of the torsional forces acting on the bridge are included for the more accurate train/track/bridge interaction analysis. The results of the analyses are compared with the field test data to verify the performance of the 2-dimensional train/track/bridge interaction analysis method.

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A Study on the Lond Characteristics of Air-Lublicated Hydrodynamic Wave Journal Bearing (공기윤활 웨이브 저어널 베어링의 부하 특성에 관한 연구)

  • 조성욱;임윤철
    • Tribology and Lubricants
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    • v.17 no.1
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    • pp.28-32
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    • 2001
  • A new bearing concept, the wave journal bearing, has been developed to improve the static and dynamic performances of an air-lubricated hydrodynamic journal bearing. This concept features waves on bearing surface. In this study, we present the solution of the compressible Reynolds equation valid for arbitrary Knudsen numbers. Straight wave journal bearing is investigated numerically. The performances of straight wave bearing are compared to the plain journal bearing over relatively wide range of bearing number and eccentricity. The wave journal bearing offers better stability than the plain journal bearing under all bearing numbers covered in this study. The bearing load and stability characteristics are dependent on the geometric parameters such as the amplitude and the starting point of the wave relative to the applied load. Under the condition of Knudsen number>0.01, we can not ignore the effect of slip for Journal bearing.

3-Dimensional Modeling and Sensitivity Analysis for Vibration Reduction of the Spin-Coater System (스핀 코터 시스템의 진동 저감을 위한 3차원 모델링과 민감도 해석)

  • 채호철;류인철;한창수
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.209-217
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    • 2003
  • In this paper, the dynamic system modeling and the state sensitivity analysis of the spin-coater system are proposed for the reduction of the vibration. In the respect of modeling, the spin-coater system is considered to be composed of servomotor, spindle, supporting base and so on. Each component of model is combined and derived to 3 dimensional equations. The combined model is verified by experimental values of actual system in the frequency domain. By direct differentiation of the constraint equations with respect to kinematic design variables, such as eccentricity of spindle, moment of inertia, rotational stiffness and damping of supported base, sensitivity equations are derived to the verified state equations. Sensitivity of design variables could be used for vibration reduction and natural frequency shift in the frequency domain. Finally, dominant design variables are selected from the sensitivity analysis.