• Title, Summary, Keyword: vibration-based monitoring

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Vibration-based Structural Health Monitoring of Caisson-type Breakwaters Damaged on Rubble Mound (사석마운드가 손상된 케이슨식 방파제의 진동기반 구조건전성 모니터링)

  • Lee, So-Young;Kim, Jeong-Tae;Kim, Heon-Tae
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.90-98
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    • 2010
  • In this paper, vibration-based structural health monitoring methods that are suitable for caisson-type structures are examined by an experimental evaluation. To achieve the objective, four approaches are implemented. First, vibration-based structural health monitoring methods are selected to monitor the structural condition of caisson-type breakwaters. Second, a lab-scaled caisson structure is constructed to verify the selected monitoring methods. Third, the vibration characteristics are numerically analyzed using an FE model due to the change in the rubble mound condition. Finally, experimental vibration tests of the lab-scaled caisson structure are performed to monitor the vibration responses due to changes in rubble mound conditions and the performances of the selected methods are examined from the monitoring results.

Implementation of Spectrum Analysis System for Vibration Monitoring

  • Nguyen, Thanh Ngoc;Jeon, Taehyun
    • International Journal of Internet, Broadcasting and Communication
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    • v.11 no.2
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    • pp.27-30
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    • 2019
  • Factory monitoring systems are gaining importance in wide areas of industry. Especially, there have been many efforts in implementation of vibration measurement and analysis for monitoring the status of rotating machines. In this paper, a digital signal processor (DSP) based monitoring system dedicated to the vibration monitoring and analysis on rotating machines is discussed. Vibration signals are acquired and processed for the continuous monitoring of the machine status. Time domain signals and fast Fourier transform (FFT) are used for vibration analysis. All of the signal processing procedures are done in the DSP to reduce the production and maintenance cost. The developed system could also provide remote and mobile monitoring capabilities to operator via internet connection. This paper describes the overview of the functional blocks of the implemented system. Test results based on signals from small-size single phase motors are discussed for monitoring and defect diagnosis of the machine status.

Wireless structural health monitoring of stay cables under two consecutive typhoons

  • Kim, Jeong-Tae;Huynh, Thanh-Canh;Lee, So-Young
    • Structural Monitoring and Maintenance
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    • v.1 no.1
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    • pp.47-67
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    • 2014
  • This study has been motivated to examine the performance of a wireless sensor system under the typhoons as well as to analyze the effect of the typhoons on the bridge's vibration responses and the variation of cable forces. During the long-term field experiment on a real cable-stayed bridge in years 2011-2012, the bridge had experienced two consecutive typhoons, Bolaven and Tembin, and the wireless sensor system had recorded data of wind speeds and vibration responses from a few survived sensor nodes. In this paper, the wireless structural health monitoring of stay cables under the two consecutive typhoons is presented. Firstly, the wireless monitoring system for cable-stayed bridge is described. Multi-scale vibration sensor nodes are utilized to measure both acceleration and PZT dynamic strain from stay cables. Also, cable forces are estimated by a tension force monitoring software based on vibration properties. Secondly, the cable-stayed bridge with the wireless monitoring system is described and its wireless monitoring capacities for deck and cables are evaluated. Finally, the structural health monitoring of stay cables under the attack of the two typhoons is described. Wind-induced deck vibration, cable vibration and cable force variation are examined based on the field measurements in the cable-stayed bridge under the two consecutive typhoons.

Development of knowledge based expert system for fault diag industrial rotating machinery (산업용 회전 기기의 현장 이상 진단을 위한 지식 기반 전문가 시스템 개발)

  • 이태욱;이용복;김승종;김창호;임윤철
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.633-639
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    • 2001
  • This paper proposes a knowledge-based expert system. which is assembled into hardware organized with sensor module. AID converter, USB. data acquisition PC and software composed of monitoring and diagnosis module combined with a frame-based method using Sohre's chart and a rule-based method. Vibration signals using various sensors are acquired by AID converter. transferred into PC and processed to obtain a continuous monitoring of the machine status displayed into several plots. Through combining frame-base which covers wide vibration causes with rule-base which gives relatively specified diagnosis results, high accuracy of fault diagnosis can be guaranteed and knowledge base can be easily extended by adding new causes or symptoms. Some examples using experimental data show the good feasibility of the proposed algorithm for condition monitoring and diagnosis of industrial rotating machinery.

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Fiber Optic Sensor Design for the Monitoring of Structural Sound and Vibration (구조물 음향진동 모니터링을 위한 광섬유 센서 설계)

  • Lee, Jong-Kil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.81-84
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    • 2007
  • In this paper, fiber optic sound and vibration monitoring sensor which is latticed shape structure based on Sagnac interferometer is fabricated and tested in laboratory conditions. To detect external vibrations surface mounted fibers on the latticed steel wire fence with a dimension of 170cm by 180cm is used. To detect external sound frequency the tightened fiber optic itself wire netting fence with a dimension of 50cm by 50cm is used. Experiments for the detection of the excited vibration and sound signals were performed. A small vibrator induced external vibration signal and it is applied to the latticed structure in the range of 100Hz to several kHz. External sound signal applied to the fiber optic sensor net using non-directional sound speaker. The detected optical signals were compared and analyzed to the detected both accelerometer and microphone signals in the time and frequency domain. Based on the experimental results, distributed fiber optic sensor using Sagnac interferometer detected effectively external vibration and sound signal and had a good performance. This system can be expanded to the monitoring of a significant system and to the structural health monitoring system.

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Vibration-based Energy Harvester for Wireless Condition Monitoring System (무선 상태감시 시스템용 진동 기반 에너지 획득 장치)

  • Cho, Sung-Won;Son, Jong-Duk;Yang, Bo-Suk;Choi, Byeong-Keun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.4
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    • pp.393-399
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    • 2009
  • Historically, industrial condition monitoring has been performed by costly hard-wired sensors or infrequent checks by maintenance personnel equipped with hand held monitoring equipment. Self- powered wireless condition monitoring systems provides on-line monitoring of critical plant and machinery providing major operating cost benefits. A vibration energy harvester(VEH) is a device that converts kinetic energy occurred by machine vibration into useable electrical energy. Using VEHs to power wireless monitoring systems can yield significant benefits: increased reliability, lower life time costs and no battery disposal issues, etc. This paper proposes the novel prototype design and manufacturing of a VEH that can eliminate the effect by failed batteries.

Vibration-based damage monitoring of harbor caisson structure with damaged foundation-structure interface

  • Lee, So-Young;Nguyen, Khac-Duy;Huynh, Thanh-Canh;Kim, Jeong-Tae;Yi, Jin-Hak;Han, Sang-Hun
    • Smart Structures and Systems
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    • v.10 no.6
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    • pp.517-546
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    • 2012
  • In this paper, vibration-based methods to monitor damage in foundation-structure interface of harbor caisson structure are presented. The following approaches are implemented to achieve the objective. Firstly, vibration-based damage monitoring methods utilizing a variety of vibration features are selected for harbor caisson structure. Autoregressive (AR) model for time-series analysis and power spectral density (PSD) for frequency-domain analysis are selected to detect the change in the caisson structure. Also, the changes in modal parameters such as natural frequency and mode shape are examined for damage monitoring in the structure. Secondly, the feasibility of damage monitoring methods is experimentally examined on an un-submerged lab-scaled mono-caisson. Finally, numerical analysis of un-submerged mono-caisson, submerged mono-caisson and un-submerged interlocked multiple-caissons are carried out to examine the effect of boundary-dependent parameters on the damage monitoring of harbor caisson structures.

Self-reliant wireless health monitoring based on tuned-mass-damper mechanism

  • Makihara, Kanjuro;Hirai, Hidekazu;Yamamoto, Yuta;Fukunaga, Hisao
    • Smart Structures and Systems
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    • v.15 no.6
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    • pp.1625-1642
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    • 2015
  • We propose an electrically self-reliant structural health monitoring (SHM) system that is able to wirelessly transmit sensing data using electrical power generated by vibration without the need for additional external power sources. The provision of reliable electricity to wireless SHM systems is a highly important issue that has often been ignored, and to expand the applicability of various wireless SHM innovations, it will be necessary to develop comprehensive wireless SHM devices including stable electricity sources. In light of this need, we propose a new, highly efficient vibration-powered generator based on a tuned-mass-damper (TMD) mechanism that is quite suitable for vibration-based SHM. The charging time of the TMD generator is shorter than that of conventional generators based on the impedance matching method, and the proposed TMD generator can harvest 16 times the amount of energy that a conventional generator can. The charging time of an SHM wireless transmitter is quantitatively formulated. We conduct wireless monitoring experiments to validate a wireless SHM system composed of a self-reliant SHM and a vibration-powered TMD generator.

Hybrid acceleration-impedance sensor nodes on Imote2-platform for damage monitoring in steel girder connections

  • Kim, Jeong-Tae;Park, Jae-Hyung;Hong, Dong-Soo;Ho, Duc-Duy
    • Smart Structures and Systems
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    • v.7 no.5
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    • pp.393-416
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    • 2011
  • Hybrid acceleration-impedance sensor nodes on Imote2-platform are designed for damage monitoring in steel girder connections. Thus, the feasibility of the sensor nodes is examined about its performance for vibration-based global monitoring and impedance-based local monitoring in the structural systems. To achieve the objective, the following approaches are implemented. First, a damage monitoring scheme is described in parallel with global vibration-based methods and local impedance-based methods. Second, multi-scale sensor nodes that enable combined acceleration-impedance monitoring are described on the design of hardware components and embedded software to operate. Third, the performances of the multi-scale sensor nodes are experimentally evaluated from damage monitoring in a lab-scaled steel girder with bolted connection joints.

Vibration Monitoring of a 1kW Small Wind Turbine Generator (1kW소형 풍력발전기의 진동 모니터링)

  • Kim, Seock-Hyun;Nam, Y.S.;Yoo, N.S.;Kim, Yun-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • pp.308-311
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    • 2006
  • A vibration monitoring is performed on a 1kW class stand alone wind turbine(W/T). When a W/T model is developed, general performance under various wind condition should be verified to introduce the product in the market. Especially, vibration characteristics within operating speed range are very important in the aspect of structural stability as well as generator's electrical efficiency. This paper examines the vibration performance of a home made 1kW W/T Various data of the W/T model are acquired in real time using a remote vibration monitoring system installed in Daekwanryung test site. Vibration stability of the W/T structure is diagnosed based upon the data and the result is used to estimate the applicability of the W/T model.

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