• Title, Summary, Keyword: phased application

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A Study on the Application of Phased Array Ultrasonic Testing to Main Steam Line in Nuclear Power Plants (원전 주증기배관 웰더렛 용접부 위상배열초음파검사 적용연구)

  • Lee, Seung-Pyo;Kim, Jin-Hoi
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.7 no.3
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    • pp.40-47
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    • 2011
  • KSNPs(Korea Standard Nuclear Power Plant) have been applied the break exclusion criteria to the high energy lines passing through containment penetration area to ensure that piping failures would not cause the loss of containment isolation function, and to reduce the resulting dynamic effects. Systems with the criteria are the Main Steam system, Feed Water system, Steam Generator Blowdown system, and Chemical & Volume Control system. In accordance with FSAR(Final Safety Analysis Report), a 100% volumetric examination by augmented in-service inspection of all pipe welds appled the break exclusion criteria is required for the break exclusion application piping. However, it is difficult to fully satisfy the requirements of inspection because 12", 8" and 6" weldolet weldments of Main Steam pipe line have complex structural shapes. To resolve the difficulty on the application of conventional UT(Ultrasonic Testing) technique, realistic mock-ups and UT calibration blocks were made. Simulations of conventional UT were performed utilizing CIVA, a commercial NDE(Nondestructive Examination) simulation software. Phased array UT experiments were performed through mock-up including artificial notch type flaws. A phased array UT technique is finally developed to improve the reliability of ultrasonic test at main steam line pipe to 12", 8" and 6" branch connection weld.

The Development of a Beam Steering System for X-band 2-D Phased Array Antenna (X-대역 2차원 위상배열안테나 빔조향 시스템 개발)

  • Kim, Doo-Soo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.4
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    • pp.92-98
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    • 2008
  • A beam steering system of X-band 2-D phased array antenna for radar application is developed. The beam steering system consists of real-time command generator, beam steering unit, control PCB of array module and power supply. It plays a role of beam steering and on-line check of phased array antenna. The performance of beam steering system is verified with pulse timing of current control in phase shifters and measurement of far-field of phased array antenna. The developed beam steering system offers basic technology to develop full-scale beam steering system of multi-function radar.

Feasibility Study for Low Pressure Turbine Inspection of Nuclear Power Plant Using Shear Wave Phased Array Ultrasonic Transducer (횡파 위상배열 초음파탐촉자를 이용한 원자력발전소 저압 터빈 검사 적용 타당성 연구)

  • Yoon, Byung Sik;Kim, Yong Sik;Kim, Jin Hoi
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.9 no.1
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    • pp.8-14
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    • 2013
  • Steam turbine blades and discs of nuclear power plants are one of the most highly stressed areas of turbine rotor, and periodic inspection of the blade roots is essential for monitoring integrity and preventing turbine failure. Ultrasonic technique is applied for volumetric inspection of blade root. However, the complexity of blade root geometry imposes challenges to inspection of blades and discs. Recently, phased array ultrasonic inspection technology is being applied to numerous power generation inspection applications including turbine rotor. The phased array ultrasonic technique requires customized inspection wedges which are generally necessary to generate effectively higher incident angle. But the usage of this wedge can cause access limitation for the lower stage blades of turbine because of the wedge front length. Therefore, the shear wave phased array probe which can generate high inspection angle without wedge is essentially necessary. In this study, feasibility study is conducted for the shear wave phased array ultrasonic probe application to blade and disc inspection. As results, the experimental results show that the shear wave phased array probe can detect the flaw and measure its size with reliable accuracy. Therefore if this shear wave phased array probe is applied to field inspection of blade and disc, more reliable inspection is expected for turbine having access limitation.

Near-Field Receiving Measurement of Active Phased Array Antenna for Full Digital Radar Application (완전 디지털 레이다에 적용 가능한 능동위상배열안테나 근접전계 수신 시험)

  • Chae, Heeduck;Lee, Jae-Min;Kim, Young-Wan;Kim, HanSaeng;Jin, Hyoung Seog;Park, Jongkuk
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.7
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    • pp.625-634
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    • 2016
  • A full digital receiving active phased array antenna generates final receiving beams by digital beam forming of received digital signals in element-level that makes difficult to use typical near-field measurement method. Thus in this paper, a modified near-field measurement method which is suitable for full digital receiving active phased array antenna is proposed. Also the measured results of receiving beam pattern and G/T using developed L-band full digital receiving active phased array antenna are shown for the verification of proposed method.

Numerical Analysis of Ultrasonic Beam Profile Due to the Change of the Number of Piezoelectric Elements for Phased Array Transducer (Phased Array트랜스듀서에 있어서 구성 압전소자수의 변화에 따른 초음파 빔 전파 특성의 수치 해석)

  • Choi, Sang-Woo;Lee, Joon-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.19 no.3
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    • pp.207-216
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    • 1999
  • A phased array is a multi-element piezoelectric device whose elements are individually excited by electric pulses at programmed delay time. One of the advantages of using phased array in nondestructive evaluation (NDE) application over conventional ultrasonic transducers is their great maneuverability of ultrasonic beam. There are some parameters such as the number and the size of the piezoelectric elements and the inter-element spacing of the elements to design phased array transducer. In this study, the characteristic of ultrasonic beam for phased array transducer due to the variation of the number of elements has been simulated for ultrasonic SH-wave on the basis of Huygen's principle. Ultrasonic beam directivity and focusing due to the change of time delay of each element were discussed due to the change of the number of piezoelectric elements. It was found that ultrasonic beam was much more spreaded and hence its sound pressure was decreased as steering angle of ultrasonic beam was increased. In addition, the ability of ultrasonic bean focusing decreased gradually with the increase of focal length at the same piezoelectric elements. However, the ability of beam focusing was improved as the number of consisting elements was increased.

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Development and Application of Phased Array System for Defect Imaging in Plate-like Structures (평판 구조물의 영상화를 위한 위상 배열 시스템 개발 및 응용)

  • Lee, Joo Kyung;Kwon, Young Eui;Lee, Heung Son;Seung, Hong Min;Kim, Ki Yeon;Lee, Jun Kyu;Kim, Hoe Woong;Lee, Ho Cheol;Kim, Yoon Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.2
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    • pp.123-130
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    • 2014
  • An ultrasonic magnetostrictive transducer-based phased-array system for imaging defects in plate structures is newly proposed. In that most ultrasonic phased array systems rely on piezoelectric transducers or electromagnetic acoustic transducers, this system has its own unique feature of employing magnetostrictive transducers. Interest in using a phased array system using magnetostrictive transducers has been recently reported for pipe inspection but no such system has been developed for plate inspection. In this investigation, we aim to propose a phased array system using OL-MPTs (Omnidirectional Lamb wave Magnetostrictive Patch Transducers) for plate inspection. The developed system consists of a multi-channel function generator, power amplifiers, preamplifiers and a data acquisition unit. In the process of its development, each of the units must be checked and in doing so, we suggest types of ultrasonic wave experiments that should be carried out. Finally, the phased system using a transducer array composed of eight OL-MPTs is newly configured and is applied for actual crack detection experiments.

The Study of Time Phased Reorder Models for Non-Instaneous Receipt with Learning Effect (수시접수 및 학습효과를 고려한 기간별 재발주 모형에 관한 연구)

  • 남호기
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.19 no.40
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    • pp.321-327
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    • 1996
  • Time phased reorder models for non-instaneous receipt was Presented in a recent paper [l]. This paper extends the models under learning effects and learning retention after breaks. The result of this model show that learning and learning retention significantly influence the amount of inventory and production lot size. Sample example demonstrate the application of the proposed methodology.

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Strategy and Application of Phased Context Teaching-Learning for Helping Physics Learning (물리 학습을 돕기 위한 단계적 상황 교수·학습 전략 및 적용)

  • Song, Youngwook;Choi, Hyukjoon
    • Journal of Science Education
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    • v.39 no.3
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    • pp.333-342
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    • 2015
  • The purpose of this research was to investigate the effect of physics learning through the teaching-learning strategy of phased context in introductory physics classes. The participants in the study included 35 university freshmen. The teaching-learning strategy of phased context were developed by idealizing, extending and comparing contexts which were then applied in introductory physics classes : six hour classes about straight line motion, two-dimensional motion and Newton's laws of motion. The effects of the physics learning were then analyzed by the FCI (Force Concept Inventory) and MPEX (Maryland Survey on Physics Expectation) questionnaires. The results showed that the teaching-learning strategy of phased context helped change the force concept and did not change the belief about physics learning. Finally, based on the results of the study, we discuss possible educational implications for phased context in introductory physics classes.

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Simulation of Ultrasonic Beam Focusing on a Defect in Anisotropic, Inhomogeneous Media

  • Jeong, Hyun-Jo;Cho, Sung-Jong;Erdenetuya, Sharaa;Jung, Duck-Yong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.6
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    • pp.635-641
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    • 2011
  • In ultrasonic testing of dissimilar metal welds, application of phased array technique in terms of incident beam focusing is not easy because of complicated material structures formed during the multi-pass welding process. Time reversal(TR) techniques can overcome some limitations of phased array since they are self-focusing that does not depend on the geometrical and physical properties of testing components. In this paper, we test the possibility of TR focusing on a defect within anisotropic, heterogeneous austenitic welds. A commercial simulation software is employed for TR focusing and imaging of a side-drilled hole. The performance of time reversed adaptive focal law is compared with those of calculated focal laws for both anisotropic and isotropic welds.

Phased Array Ultrasonic Application for Defects Estimation of FRP Box Member (FRP 박스부재의 결함평가를 위한 위상배열초음파 적용성 평가)

  • Kwak, Kae-Hwan;Yang, Dong-Woon;Kim, Ho-Sun;Lee, Ho-Hyun;Yun, Kuk-Hyun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.5
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    • pp.69-76
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    • 2010
  • The structural material with the highest possibility of new materials that will be used in the future construction field is fiber reinforced polymer. The current studies on FRP members by using such excellent material characteristics mostly focused on stability, composite problem, and durability of FRP members. The initially constructed FRP members secure excellent stability and durability compared to reinforced concrete and steel materials, but measures for defections during the periodical inspection, methods for detecting breakages, and maintenance and reinforcement are not insufficient. Accordingly, this study proposed a measurement system using the FRP sensor to evaluate the safety of the FRP modular box member, and applied the phased array ultrasonic technique to detect the defects and damage likely to occur during the performance period.