• Title/Summary/Keyword: coaxial monitoring

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Coaxial Monitoring during Laser Lap Welding (겹치기 이음부의 레이저용접 동축 모니터링)

  • Kim, Jung-Hak;Kim, Cheol-Hee;Kim, Jeong-Han;Rhee, Se-Hun
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1294-1298
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    • 2007
  • Welding process monitoring is advantageous for maintaining weld quality and numerous sensing techniques have been developed for laser welding. Coaxial image monitoring enables direct monitoring of the weld pool shape and keyhole behavior, but requires the complex optical system and the image processing technique. In this study, we coaxially acquired the weld pool images during laser lap welding by using the camera and special illumination. The welding characteristics - pool width and length, keyhole shape, etc - were extracted by using image processing and the relationship between these characteristics and the penetration depth were investigated.

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Development of Coaxial Monitoring System in Laser Arc Hybrid Welding for Automotive Body Application (자동차 차체 적용을 위한 레이저-아크 하이브리드 용접의 동축 모니터링 시스템 개발)

  • Park, Young-Whan;Rhee, Se-Hun;Kim, Cheol-Hee
    • Journal of Welding and Joining
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    • v.27 no.6
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    • pp.9-16
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    • 2009
  • In this paper, the coaxial monitoring system to capture image of weld pool was developed in laser-arc hybrid welding. In order to obtain the reliable image, green laser was used as a illumination system and measuring components such as band pass filter, ND (Neutral Density) filter and shutter speed was designed and optimized. Using this monitoring system, weld pool images were captured according to laser power, welding speed, welding current and interspace between laser and arc through the experiment. ANOVA (Analysis of Variation) was carried out to identify the influence of process variables on bead widths extracted from captured images of monitoring system. Welding speed and current were major factor to affect weld pool.

Application of Time Domain Reflectometry to the Monitoring or Rock Mass Deformation with Coaxial Cable (동축 케이블을 이용한 시간영역 반사법의 암반변위 계측에의 적용)

  • 정슬람;정소걸;정현기;박철환;박철환;이희근
    • Tunnel and Underground Space
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    • v.6 no.4
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    • pp.306-315
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    • 1996
  • This paper presents an application of the TDR(Time Domain Reflectometry) to the monitoring of the deformation of rock mass with grouted coaxial cables through laboratory tests. The grouted cable can easily deform together with the rock mass movements, and the deformed cable loses its original capacitance and the reflected waveform produced along the deformed cable consequently represents a change of voltage pulse. Therefore, it is possible to monitor the deformation of rock mass by measuring the changes in these reflection signatures. Shear test of the cemented mortar containing a specimen of coaxial cable showed that the shear deformation correlated linearly with the reflection coefficient, so the TDR was effective to monitor the displacement of the rock mass. Bending test were carried out in order to determine the influence of the crooked cables on the monitoring of rock mass movements. Controlled cirmping and shearing test upon a cable of 50 m long, 12.7 mm diameter showed not only the fact that the reflection amplitudes decreased as the cable length increased but also the proper crimping depth, width and interval between two adjacent crimps. Two coaxial cables-one 100 m long and other 175m long-were installed and grouted into the separate boreholes drilled in a sedimentary formation. The behavior of the cable was monitored with metallic TDR cable tester to measure rock mass deformation based on the interpretative techniques developed through laboratory tests.

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A practical modification to coaxial cables as damage sensor with TDR in obscured structural members and RC piles

  • Mehmet Ozgur;Sami Arsoy
    • Structural Monitoring and Maintenance
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    • v.10 no.2
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    • pp.133-154
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    • 2023
  • Obscured structural members are mostly under-evaluated during condition assessment due to lack of visual inspection capability. Insufficient information about the integrity of these structural members poses a significant risk for public safety. Time domain reflectometry (TDR) is a novel approach in structural health monitoring (SHM). Ordinary coaxial cables "as is" without a major modification are not suitable for SHM with TDR. The objective of this study is to propose a practical and cost-effective modification approach to commercially available coaxial cables in order to use them as a "cable sensor" for damage detection with the TDR equipment for obscured structural members. The experimental validation and assessment of the proposed modification approach was achieved by conducting 3-point bending tests of the model piles as a representative obscured structural member. It can be noted that the RG59/U-6 and RG6/U-4 cable sensors expose higher strain sensitivity in comparison with non-modified "as is" versions of the cables used. As a result, the cable sensors have the capability of sensing both the presence and the location of a structural damage with a maximum aberration of 3 cm. Furthermore, the crack development can be monitored by the RG59/U-6 cable sensor with a simple calibration.

Implementation of A Bridge Monitoring System Based on Ubiquitous Sensor Networks (USN기반의 교량 모니터링 시스템 구현)

  • Lee, Sung-Hwa;Jeon, Min-Suk;Lee, An-Kyu;Kim, Jin-Tae
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.9 no.4
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    • pp.1-8
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    • 2009
  • The proposed real-time structural health monitoring(SHM) system in past transferred and received data, central server gathered data from sensors, through coaxial cable. an immense sum of money is required to structure sensor network using coaxial cable. This paper proposes USN-based structural health monitoring(SHM). AIso, this paper designs and realizes prototypes according to proposed SHM. The value of sensing data obtained through HSDPA transfer to the BMS(Bridge Monitoring Server) passing through the TCP / IP socket by building two-way communication system, We have implemented a complete graph converting full system.

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Condition Monitoring System: High Performance Wireless Measurement System (기계 상태 감시: 임베디드형의 고성능 무선 측정시스템)

  • Shim, M.C.;Yang, B.S.
    • Journal of Power System Engineering
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    • v.11 no.1
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    • pp.28-32
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    • 2007
  • This research proposed that development of wireless condition monitoring system using WLAN network. It offers the prospect of improved performance that removed a current a coaxial cable and reduced overall cost of condition monitoring. Recently, there is an interesting concern for wireless system as an infrastructure technology construct ubiquitous computing environment in the future. High performance computing board makes minimization with integrate of a various functions which support wireless LAN network. Instead of wired coaxial cable using measurement system in industry, wireless LAN network assists industry automation and engineer's convenience. Developed system adapted wireless LAN network on shipboard with engine room and deck house, it also executes wireless measurement test on 8500TEU containership.

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Implementation of condition monitoring system in underground utility tunnels using inductive coupler (유도성 커플러를 이용한 지하공동구의 상태감시시스템)

  • Ju, Woo-Jin;Kim, Hyun-Sik
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.8
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    • pp.1597-1603
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    • 2017
  • The incidence of fire in underground utility tunnel is lower than other fires, but the damage caused by fire can cause social loss due to social management paralysis as well as economic loss. Hereupon, this paper presents the results of an empirical test on the construction of the underground utility tunnel condition monitoring system using the leakage coaxial cable installed in the underground utility tunnel. For this reason, a verification test was conducted by connecting a inductive coupler 200 Mbps power line communication modem with insertion loss characteristics of $-6{\pm}2dB$ to the installed the leakage coaxial cable installed in the underground utility tunnel. As a result, We confirmed sending/receiving of IP cameras up to 500 m. Therefore, it is judged that it is possible to construct a condition monitoring system for underground utility tunnel by using the leakage coaxial cables installed in the underground utility tunnels without installing additional communication lines for data transmission.

Crack mapping in RC members using distributed coaxial cable crack sensors: modeling and application

  • Greene, Gary Jr.;Belarbi, Abdeldjelil;Chen, Genda
    • Smart Structures and Systems
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    • v.1 no.4
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    • pp.385-404
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    • 2005
  • The paper presents a model to calculate reinforcement strain using measured crack width in members under applied tension, flexure, and/or shear stress. Crack mapping using a new type of distributed coaxial cable sensors for health monitoring of large-scale civil engineering infrastructure was recently proposed and developed by the authors. This paper shows the results and performance of such sensors mounted on near surface of two flexural beams and a large scale reinforced concrete box girder that was subjected to cyclic combined shear and torsion. The main objectives of this health monitoring study was to correlate the sensor's response to strain in the member, and show that magnitude of the signal's reflection coefficient is related to increases in applied load, repeated cycles, cracking, and reinforcement yielding. The effect of multiple adjacent cracks, and signal loss was also investigated. The results shown in this paper are an important step in using the sensors for crack mapping and determining reinforcement strain for in-situ structures.

Method for Power control of Wired and Wireless linkage Sensor Network for Low-power Wireless network (저전력 무선 네트워크를 위한 유무선 연동 센서 네트워크의 전력 제어 방법)

  • Lee, Kyung-Sook;Kim, Hyun-Deok
    • Convergence Security Journal
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    • v.12 no.3
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    • pp.27-34
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    • 2012
  • In this paper, using a new low-power consumption method for ZigBee device, which consume low-power using an output power control algorithm through RSSI monitoring as interlocking wireless network using ZigBee which has advantages of a low-power consumption, a low-cost, a compatibility and a draft international standardization enacted by IEEE and ZigBee Alliance, with wired network using built coaxial cable to overcome the disadvantage of the existing wireless sensor network, is proposed. Effectiveness of the output power control algorithm through RSSI monitoring has been verified by experimentation for more optimized low-power consumption.