• 제목/요약/키워드: Strip Vibration

검색결과 100건 처리시간 0.023초

비정수 차수를 갖는 비례적분미분제어법과 가우시안 혼합모델을 이용한 연속아연도금라인에서의 전자기 제진제어 기술 (Electromagnetic Strip Stabilization Control in a Continuous Galvanizing Line using Mixture of Gaussian Model Tuned Fractional PID Controller)

  • 구배영;원상철
    • 제어로봇시스템학회논문지
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    • 제21권8호
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    • pp.718-722
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    • 2015
  • This paper proposes a fractional-order PID (Proportional-Integral-Derivative) control used electromagnetic strip stabilization controller in a continuous galvanizing line. Compared to a conventional PID controller, a fractional-order PID controller has integration-fractional-order and derivation-fractional-order as additional control parameters. Thanks to increased control parameters, more precise controller adjustment is available. In addition, accurate transfer function of a real system generally has a fractional-order form. Therefore, it is more adequate to use a fractional-order PID controller than a conventional PID controller for a real world system. Finite element models of a $1200{\times}2000{\times}0.8mm$ strip, which were extracted using a commercial software ANSYS were used as simulation plants, and Gaussian mixture models were used to find optimized control parameters that can reduce the strip vibrations to the lowest amplitude. Simulation results show that a fractional-order PID controller significantly reduces strip vibration and transient response time than a conventional PID controller.

열간 사상압연기에서의 진동 원인 (The Cause of Vibration at Finishing Stands in a Hot Strip Mill)

  • 손붕호;노용래;이영호
    • 소음진동
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    • 제4권1호
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    • pp.43-50
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    • 1994
  • Chatter vibration of a rolling machine in steel plants has a significant effect on thickness quality of the products. The cause and mechanism of the mill chattering is addressed through measurement of vibration and dynamic torque. An FFT system and an FM telemetry system are employed to collect data at several locations of possible damages. The results reveal the followings as sources of the mill vibration. The first is defects in roller bearings of a work roll chock. The second is instability of an oil film bearing in a backup roll chock, which has been investigated with a theoretical model describing the phenomenon. Dynamic torque is not the direct cause of mill vibration but rather influenced by the vibration. Appropriate treatment methods are suggested to address each of the above sources.

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플랫 블레이드 윈드실드 와이퍼의 역전 진동 저감에 관한 연구 (A Study on the Attenuation of Flip-over Vibration in the Flat Blade Windshield Wiper)

  • 이형일
    • 한국소음진동공학회논문집
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    • 제22권10호
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    • pp.974-984
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    • 2012
  • 플랫 블레이드 와이퍼의 블레이드의 누름압 분포를 조정하여 역전과정에서 발생되는 진동을 저감하는 방법을 제시하였다. 블레이드와 유리면 사이에 길이방향으로 불균일한 누름압 분포를 도입, 고무스트립에 점진적인 역전을 유도함으로써 역전과정에서 발생하는 충격력을 저감하였다. 블레이드 내의 바디스프링 형상을 이전 연구에서 제시된 방법을 통해 구해진 형태를 적용함으로써 누름압 분포를 조정하였다. 이 방법을 적용하여 전체 길이에 균일한 누름압과 불균일한 누름압을 발생시키는 두 종류의 블레이드를 개발한 다음 누름압을 측정하여 확인하였다. 두 블레이드에서 발생하는 수직방향 및 횡방향 진동을 측정 비교한 결과, 불균일한 누름압을 가진 블레이드가 균일한 누름압의 블레이드에 비해 훨씬 작은 수직방향 진동을 나타냄을 확인하였다.

550MW급 초초임계압(USC, Ultra Super Critical) 증기터빈의 Spike Vibration 에 관한 원인 규명 및 대책 (Root Cause and Countermeasure on the Spike Vibration of a 550MW Class USC(Ultra Super Critical) Steam Turbine)

  • 양승헌;김용석;나운학
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.442-447
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    • 2007
  • A very abnormal vibration was occurred at the LP(low pressure) turbine continuously during the pre-operation for a 550MW class USC(ultra super critical) steam turbine. This vibration was initiated at the rotating speed of about 3,450rpm and then the vibration amplitude was highly increased the number by $2{\sim}3$ times with the increase of the rotating speed to the rated speed(3,600rpm). In this paper, this abnormal vibration named spike vibration. This spike vibration was caused by the rubbing between the rotating bucket tip seal and the Lower Half of spill strip. Also, this paper presents the mechanism of the spike vibration and the proper method to eliminate this abnormal vibration problem. This result would be good practice to find the solution of similar high vibration in the USC steam turbines for power plant as well as industrial rotating machineries.

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550MW급 초초임계압(USC, ultra super critical) 증기터빈의 Spike Vibration에 관한 원인 규명 및 대책 (Root Cause and Countermeasure on the Spike Vibration of a 550MW Class USC(ultra super critical) Steam Turbine)

  • 양승헌;김용석;나운학;박종권
    • 한국소음진동공학회논문집
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    • 제17권12호
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    • pp.1238-1245
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    • 2007
  • A very abnormal vibration was occurred at the LP(low pressure) turbine continuously during the pre-operation for a 550MW class USC(ultra super critical) steam turbine. This vibration was initiated at the rotating speed of about 3,450 rpm and then the vibration amplitude was highly increased the number by $2{\sim}3$ times with the increase of the rotating speed to the rated speed (3,600 rpm). In this paper, this abnormal vibration named spike vibration. This spike vibration was caused by the rubbing between the rotating bucket tip seal and the lower half of spill strip. Also, this paper presents the mechanism of the spike vibration and the proper method to eliminate this abnormal vibration problem. This result would be good practice to find the solution of similar high vibration in the USC steam turbines for power plant as well as industrial rotating machineries.

타이어의 2차원 유한 요소 모델 (2-D Finite Element Model of Tires)

  • Kim, Yong-Joe;J. Stuart Bolton
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.314.1-314
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    • 2002
  • It has been shown that the vibrational response of a tire can be represented by a set of decaying waves, each associated with a particular cross-sectional shapes, in the region near the contact patch. Thus, it can be concluded that tires can be effectively modeled as lossy waveguides. It has also been shown that the sound radiation from tires is mainly from the region close to contact patch. (omitted)

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자동차용 웨더스트립의 영구변형 예측 (Numerical Prediction of Permanent Deformation of Automotive Weather Strip)

  • 박준철;민병권;오정석;문형일;김헌영
    • 한국자동차공학회논문집
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    • 제18권4호
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    • pp.121-126
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    • 2010
  • The automotive weather strip has functions of isolating of water, dust, noise and vibration from outside. To achieve good sealing performance, weather strip should be designed to have the high contact force and wide contact area. However, these design causes excessive permanent deformation of weather strip. The causes of permanent deformation is generally explained to be the chemical material detrioration and physical variation and cyclic loading, etc. This paper introduces a numerical method to predict the permanent deformation using the time dependent viscoelastic model which is represented by Prony series in ABAQUS. Uniaxial tension and creep tests were conducted to obtain the material data. And the lab. test for the permanent deformation was accelerated during shorter time, 300 hours. The permanent deformation of weather strip was successfully predicted under the different loading conditions and different section shapes using the suggested numerical process.

Pasternak지반으로 지지된 변화폭 원호형 띠기초의 휨-비틀림 자유진동 (Flexural-Torsional Free Vibrations of Circular Strip Foundation with Variable Breadth on Pasternak Soil)

  • 이병구;박광규;강희종;윤희민
    • 한국강구조학회 논문집
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    • 제19권5호
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    • pp.539-548
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    • 2007
  • 이 논문은 Pasternak지반으로 지지된 변화폭 원호형 띠기초의 휨-비틀림 자유진동에 관한 연구이다. 띠기초의 단면은 단면깊이는 일정하고, 단면폭은 1차식으로 변화하는 변화폭을 갖는 직사각형 단면으로 채택하였다. 띠기초의 지반은 Winkler지반에 전단층을 갖는 Pasternak지반으로 모형화하였다. 이러한 원호형 띠기초의 자유진동을 지배하는 상미분방정식과 경계조건을 유도하였다. 자유진동의 관성항으로는 휨관성, 회전관성 및 비틀림관성을 고려하였다. 상미분방정식을 수치해석하여 4개의 최저차 고유진동수를 산출하였다. 수치해석의 결과로 띠기초의 변수들이 고유진동수에 미치는 영향을 고찰하였다. 이 논문의 결과는 띠기초의 동적 설계에 매우 유용한 자료를 제공할 수 있을 것으로 기대된다.

Development of Physical Treatment Technology for Stall Wastewater

  • Oh, In-Hwan;Park, Jeung-Hyun
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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    • pp.728-736
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    • 1996
  • Solid/Liquid(S/L) separation is crucial for biological treatment of animal wastewater. Liquid portion from S/L separation has less BOD-load and proper post-strip treatment can be obtained . Screen or declined sieve was normally used to separate the solid parts. For better separating efficiency a vibration and a cylindrical separator were constructed and tested. The results are summarized as follows : Solids removal efficiency and moisture content of separated solid were 15-26% and 85-88%, respectively for the vibration separator. For the cylindrical separator, solid removal efficiency and moisture content of solid were 16-39% and 86-89% , respectively. The greatest amount of drymatter was obtained when operating vibration separator with 10。 inclination and 100% vibrating power. For the cylindrical separator maximum efficiency was obtained with 40rpm and 19 inclination . The vibration and the cylindrical separator have shown 21% and 26% in BOD removal, respectively. These two types of separator were proved to be applicable methods for animal wastewater separation.

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얇은 판 스프링에 의해 지지되는 튜브의 진동 시 지지조건에 따른 마멸분석 (Wear Analysis of a Vibrating Tube supported by Thin Strip Springs incorporating the Supporting Conditions)

  • 김형규;하재욱;이영호;허성필;강흥석
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 제35회 춘계학술대회
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    • pp.63-70
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    • 2002
  • Wear on the tube-to-spring contact is investigated experimentally. The wear is caused by the vibration of the tube while the springs support it. As for the supporting conditions, applied are the contacting normal force (P) of 5 N, just-contact (P = 0 N) and the gap of 0.1 mm. The gap condition is tried far considering the influence of simultaneous impacting and sliding on wear. Results show that the wear volume increases in the order of the gap, the just-contact and the 5 N conditions. This is explained from the contact geometry of the spring, which is convex of smooth contour. The contact shear force is regarded smaller in the case of the gap existence compared with the other conditions. Wear mechanism is considered from SEM observation of the worn surface. The variation of the normal contact traction is analysed using the finite element analysis to estimate the slip displacement range on the contact with consulting the fretting map previously obtained.

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