• Title/Summary/Keyword: Microvibration

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Application of Smart Isolation Platform for Microvibration Control of High-Tech Industry Facilities (첨단기술산업 시설물의 미진동제어를 위한 스마트 면진플랫폼의 적용)

  • Kim, Hyun-Su;Kang, Joo-Won;Kim, Young-Sik
    • Journal of Korean Association for Spatial Structures
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    • v.14 no.2
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    • pp.87-94
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    • 2014
  • In this study, a smart isolation platform has been developed for control of microvibration of high-technology facilities, such as semi-conductor plants and TFT-LCD plants. Previously, microvibration control performance of a smart base isolation system has been investigated. This study compared microvibration control performance of a smart isolation platform with that of conventional base isolation and fixed base. For this purpose, train-induced ground acceleration is used for time history analysis. An MR damper was used to compose a smart isolation platform. A fuzzy logic controller was used as a control algorithm and it was optimized by a multi-objective genetic algorithm. Numerical analysis shows that a smart isolation platform can effectively control microvibration of a high-technology facility subjected to train-induced excitation compared with other models.

Protective systems for high-technology facilities against microvibration and earthquake

  • Yang, Jann N.;Agrawal, Anil K.
    • Structural Engineering and Mechanics
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    • v.10 no.6
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    • pp.561-575
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    • 2000
  • Microvibration of high technology facilities, such as semiconductor plants and facilities with high precision equipments, due to nearby road and rail traffic has attracted considerable attention recently. In this paper, a preliminary study is conducted for the possible use of various protective systems and their performance for the reduction of microvibration. Simulation results indicate that passive base isolation systems, hybrid base isolation systems, passive floor isolation systems, and hybrid floor isolation systems are quite effective and practical. In particular, the performances of hybrid floor isolation systems are remarkable. Further, passive energy dissipation systems are not effective for the reduction of microvibration. Finally, the protections against both microvibration and earthquake are also investigated and presented.

VIBRATION CHARACTERISTICS OF REINFORCED CONCRETE SLABS (철근콘크리트 슬래브의 진동 특성)

  • 변근주;노병철;방춘석;이호범
    • Proceedings of the Korea Concrete Institute Conference
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    • 1992.10a
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    • pp.218-223
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    • 1992
  • Some aspects of the design procedures of reinforced concrete slabs concerning microvibration behavior have to be considered. In this study, a numerical algorithm for the analysis of slabs to withstand the microvibration effects is developed. First, the evaluation criteria for controlling the microvibration of slabs is given from the literature survey. Second, the human-induced load model is developed by the experimental results. Finally, the procedure for the analysis of reinforced concrete slabs, with particular emphasis to the slab subject to human-induced dynamic load, is developed by the finite element method and is then examined by using the slab model tests, In addition, the effects of elastic modulus, mass, shape of slab, and support conditions on the microvibration behavior of reinforced concrete slabs are analyzed. It is concluded that the developed analysis procedure showns in accecptable accuracy compared with the experiments and the analysis procedure cab be easily appkied to the practical microvibration problems.

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Smart Microvibration Control of High-Tech Industry Facilities using Multi-Objective Genetic Algorithm (다목적 유전자알고리즘을 이용한 첨단기술산업 시설물의 스마트 미진동제어)

  • Kim, Hyun-Su;Kang, Joo-Won;Kim, Young-Sik
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.2
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    • pp.37-45
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    • 2013
  • Reduction of microvibration is regarded as important in high-technology facilities with high precision equipments. In this paper, smart control technology is used to improve the microvibration control performance. Mr damper is used to make a smart base isolation system amd fuzzy logic control algorithm is employed to appropriately control the MR damper. In order to develop optimal fuzzy control algorithm, a multi-objective genetic algorithm is used in this study. As an excitation, a train-induced ground acceleration is used for time history analysis and three-story example building structure is employed. Microvibration control performance of passive and smart base isolation systems have been investigated in this study. Numerical simulation results show that the multi-objective genetic algorithm can provide optimal fuzzy logic controllers for smart base isolation system and the smart control system can effectively reduce microvibration of a high-technology facility subjected to train-induced excitation.

Analytical & Experimental Study on Microvibration Effects of Satellite (인공위성의 미소 진동 영향성에 관한 해석 및 실험적 연구)

  • Park, Geeyong;Lee, Dae-Oen;Yoon, Jae-San;Han, Jae-Hung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.1
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    • pp.5-13
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    • 2014
  • Number of components and payload systems installed in satellites were found to be exposed to various disturbance sources such as the reaction wheel assembly, the control moment gyro, coolers, and others. A micro-level of vibration can introduce jitter problems into an optical payload system and cause significant degradation of the image quality. Moreover, the prediction of on-orbit vibration effects on the performance of optical payloads during the development process is always important. However, analyzing interactions between subsystems and predicting the vibration level of the payloads is extremely difficult. Therefore, this paper describes the analytical and experimental approach to microvibration effects on satellite optical payload performance with integrated jitter analysis frame-work, microvibration emulator and satellite structure testbed.

Active Microvibration Control System Using Maglev Actuator (자기부상방식의 능동 미세진동 제어시스템)

  • Lee, Joo-Hoon;Lee, Se-Han;Hwang, Don-Ha;Kim, Yong-Joo;Choi, Young-Kiu
    • Proceedings of the KIEE Conference
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    • 2004.07d
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    • pp.2492-2494
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    • 2004
  • A system, featuring the electromagnetic levitation actuator for control in the vertical direction, of active microvibration control was proposed. The main components of this system are a vibration isolation table with built-in acceleration sensors for detecting microvibration, electromagnetic levitation actuators with built-in permanent magnets and electromagnets, and a digital controller with high precision signal converters.

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Development of a Hybrid Mount System Combined Airspring with Piezostack Actuator for Microvibration (공기스프링과 압전작동기를 결합한 복합형 미진동 방진마운트 시스템 개발)

  • Moon, S.J.;Jung, H.J.;Shin, Y.H.;Jang, D.D.;Jeong, J.A.;Moon, Y.J.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.1
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    • pp.56-65
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    • 2011
  • A new hybrid mount system is proposed for microvibration control in a high-tech factory. The mount consists of an airspring as a passive device and a piezostack actuator as an active device. The two devices are connected in series. Some numerical simulations and experimental tests are carried out to evaluate isolation performance of the mount system comprising of four proposed hybrid mounts. As a control logic, the specific algorithm is adopted for considering multiple target frequencies of excitation based on a Filtered-X LMS algorithm. The results are compared with isolation performance of the passive airspring mount system. It is confirmed that the proposed hybrid mount system has great performance on microvibration.

Analytical & Experimental Study on Microvibration Effects of Satellite (인공위성의 미소 진동 영향성에 관한 해석 및 실험적 연구)

  • Park, Geeyong;Lee, Dae-Oen;Yoon, Jae-San;Han, Jae-Hung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.533-539
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    • 2013
  • Number of components and payload systems installed in satellites were found to be exposed to various disturbance sources such as the reaction wheel assembly, the control moment gyro, coolers, and others. A micro-level of vibration can introduce jitter problems into an optical payload system and cause significant degradation of the image quality. Moreover, the prediction of on-orbit vibration effects on the performance of optical payloads during the development process is always important. However, analyzing interactions between subsystems and predicting the vibration level of the payloads is extremely difficult. Therefore, this paper describes the analytical and experimental approach to microvibration effects on satellite optical payload performance with integrated jitter analysis framework, micro vibration emulator and satellite structure testbed.

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Microvibration analysis of a cantilever configured reaction wheel assembly

  • Zhang, Zhe;Aglietti, Guglielmo S.;Ren, Weijia;Addari, Daniele
    • Advances in aircraft and spacecraft science
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    • v.1 no.4
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    • pp.379-398
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    • 2014
  • This article discusses the microvibration analysis of a cantilever configured reaction wheel assembly. Disturbances induced by the reaction wheel assembly were measured using a previously designed platform. Modelling strategies for the effect of damping are presented. Sine-sweep tests are performed and a method is developed to model harmonic excitations based on the corresponding test results. The often ignored broadband noise is modelled by removing spikes identified in the raw signal including a method of identifying spikes from energy variation and band-stop filter design. The validation of the reaction wheel disturbance model with full excitations (harmonics and broadband noise) is presented and flaws due to missing broadband noise in conventional reaction wheel assembly microvibration analysis are discussed.

Microvibration Control of High Technology Facilities Subjected to Train-induced Excitation using Smart Base Isolation (열차진동하중을 받는 첨단시설물의 스마트 면진시스템을 이용한 미진동제어)

  • Kim, Hyun-Su;Kang, Joo-Won;Kim, Young-Sik
    • Journal of Korean Association for Spatial Structures
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    • v.12 no.2
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    • pp.99-108
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    • 2012
  • Microvibration problem of high-technology facilities, such as semi-conductor plants and TFT-LCD plants, has been considered as important factors that affects the performance of products and thus it is regarded as important in facilities with high precision equipments. In this paper, various base isolation control systems are used to investigate their microvibration control performance. To this end, train-induced ground acceleration is used for time history analysis and three-story example building structure is employed. Microvibration control performance of passive and smart base isolation systems have been investigated in this study. Based on numerical simulation results, it has been verified that smart base isolation system can control microvibration of a high-technology facility subjected to train-induced excitation.