• Title/Summary/Keyword: 비파괴탐상

Search Result 228, Processing Time 0.03 seconds

A Basic Study on Eddy Current Testing of End-Cap Welds (봉단 용접부 와전류탐상의 기초적인 연구)

  • Suh, D.M.;Sim, K.S.;Kwon, W.J.;Kim, J.H.;Park, C.H.
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.18 no.2
    • /
    • pp.85-91
    • /
    • 1998
  • In nuclear fuel manufacturing process, end-closure welding has long been recognized as requiring very high integrity. In this basic study, ECT(eddy current testing) method for end-closure welding has been developed to detect end cap weld discontinuities for nuclear fuel safety. In order to improve the inspection reliability, the maximum scanning speed and the maximum frequency is investigated for end-closure welding inspection. The bandpass filter(0-250Hz) is used for removing noise effects. This study shows that ECT method is effective and sensitive for the detection of small defect(0.35mm diameter).

  • PDF

Development of Automated Non-Destructive Ultrasonic Inspection Equipment for Welding Crack Inspection (용접크랙검사용 비파괴 초음파탐상 자동화검사장비 개발)

  • Chai, Yong-Yoong
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.15 no.1
    • /
    • pp.101-106
    • /
    • 2020
  • This research is related to a development of the ultrasonic detector for an internal defect detection of various assembly part's welding zone. In this research, measurement S/Ws including system's motion control, S/W ultrasonic transmitter/receiver control, defect judgment standard setting, etc. have been designed for ultrasonic detection, and welding defects sample network, etc. were also designed for comparison between products in good condition and defective products. Through this kind of system, automatic detection function can be performed for the depth and the defect location of the assembly parts welding zone, and the system is able to make a judgment of internal defect detection which is used to be performed by an expert in the past.

Development of the small NDT gauge using Magnetic Flux Leakage (자기 누설 탐상 방식을 이용한 소형 비파괴 검사기 개발)

  • Seong, Kyung-Jun;Jo, Bong-Kyun;Lee, Gen-Bo;Hong, Young-Whan;Park, Chi-Young;Park, Il-Whan;Park, Jung-Gil;Park, Gwan-Soo
    • Proceedings of the KIEE Conference
    • /
    • 2006.04b
    • /
    • pp.405-407
    • /
    • 2006
  • 자기누설 탐상시스템은 자성체인 구조물에 서검사 대상 물체를 자화시켜 결함부위에서 자기 누설의 여부를 측정함으로써 구조물의 결함, 부식 등을 탐지하는 시스템이다. 본 논문에서는 소형 비파괴 검사시스템을 설계하고 제작하였다. 또한 3차원 유한요소법을 이용하여 해석하고 측정하여 결과를 비교 분석하였다.

  • PDF

Scattering of Surface Waves in Anisotropic Media for Applications in Wave Barriers and Non-Destructive Evaluation (방진구조물 및 비파괴 응력파 탐상의 응용을 위한 비등방성 재료의 표면파 산란에 관한 연구)

  • 이종세
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.2 no.2
    • /
    • pp.77-85
    • /
    • 1998
  • Propagation of elastic surface waves in anisotropic media is considered in this study. An analytical technique is proposed to study the scattering of surface waves at the interface between two anisotropic quarter-spaces. The Green's function technique is used to derive a system of equations which can determine the scattering coefficients at the interface. A numerical study is carried out and the trade-offs between the material anisotropy and inhomogeneity are studied.

  • PDF

Effects of the PIG Draft Velocity on the Defect Signals in MFL NDT System (자기 누설 비파괴 탐상 시스템에서 PIG의 주행속도가 검출신호에 미치는 영향)

  • 박상호;박관수
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.52 no.10
    • /
    • pp.475-483
    • /
    • 2003
  • In this paper, dynamic characteristics of the magnetic flux leakage(MFL) type non-destructive testing(NDT) are analyzed. Effects of a sensor speed in MFL PIG system and remanent magnetization of the gas pipeline are analyzed by using 3 dimensional nonlinear finite element analysis including eddy current and hysteresis characteristics. Results show that the speed of the sensor reduces the magnitude of the sensing signals where as the hysteresis of the pipeline distorts the sensing signals.

Pipeline Defects Detection Using MFL Signals and Self Quotient Image (자기 누설 신호와 SQI를 이용한 배관 결함 검출)

  • Kim, Min-Ho;Rho, Yong-Woo;Choi, Doo-Hyun
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.30 no.4
    • /
    • pp.311-316
    • /
    • 2010
  • Defects positioning of underground gas pipelines using MFL(magnetic flux leakage) inspection which is one of non-destructive evaluation techniques is proposed in this paper. MFL signals acquired from MFL PIG(pipeline inspection gauge) have nonlinearity and distortion caused by various external disturbances. SQI(self quotient image), a compensation technique for nonlinearity and distortion of MFL signal, is used to correct positioning of pipeline defects. Through the experiments using artificial defects carved in the KOGAS pipeline simulation facility, it is found that the performance of proposed defect detection is greatly improved compared to that of the conventional DCT(discrete cosine transform) coefficients based detection.

Study for Non-Destructive Testing of Polyethylene Electrofusion Joints - Ultrasonic Imaging test (폴리에틸렌 배관의 전기융착부 비파괴검사기술에 관한 연구)

  • Kil Seong Hee;Kwon Jeong Rock
    • Journal of the Korean Institute of Gas
    • /
    • v.8 no.3 s.24
    • /
    • pp.31-36
    • /
    • 2004
  • Electrofusion(EF) joints have been widely used as they are easy to fuse and suitable for high-quality joints for polyethylene(PE) pipes. This paper studies the cause of defects and classifies 5 types of defects. The defect detection technique for electrofusion joints of polyethylene piping is utilized by the ultrasonic phased array technique to obtain ultrasonic images of electrofusion joints. Test sample joints have been designed and fabricated using artificial defects which were made using paper. Finally, we studied the condition of electrofusion in the field and analyzed the main causes of defects. And we classified the defect types as local lack of fusion, sand inclusion, voids or air inclusion, short stab, excess penetration or excess bead.

  • PDF

Performance Comparison of Pipeline Defects' Length Estimation Using MFL Signals (자기 누설 신호를 이용한 배관 결함의 길이 추정 성능 비교)

  • Kim, Tae-Wook;Rho, Yong-Woo;Choi, Doo-Hyun
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.29 no.2
    • /
    • pp.108-113
    • /
    • 2009
  • MFL(magnetic flux leakage) inspection is a general method of non-destructive evaluation(NDE) of underground gas pipelines. Pipelines are magnetized by permanent magnets when MFL PIG(pipeline inspection gauge) gets through them. If defects or corrosions exist in pipelines, effective thickness is changed and thus variation of leakage flux occurs. The leakage flux signals detected by hall-sensors are analyzed to characterize defect's geometries such as length, width, depth, and so on. This paper presents several methods for estimating defect's length using MFL signals and their performances are compared for real defects carved in KOGAS pipeline simulation facility. It is found that 80% and 90% of minimum values for axial and peak values for radial signals respectively show the best performance in the point of length estimation error.

The Basic Study on the Method of Acoustic Emission Signal Processing for the Failure Detection in the NPP Structures (원전 구조물 결함 탐지를 위한 음향방출 신호 처리 방안에 대한 기초 연구)

  • Kim, Jong-Hyun;Korea Aerospace University, Jae-Seong;Lee, Jung;Kwag, No-Gwon;Lee, Bo-Young
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.29 no.5
    • /
    • pp.485-492
    • /
    • 2009
  • The thermal fatigue crack(TFC) is one of the life-limiting mechanisms at the nuclear power plant operating conditions. In order to evaluate the structural integrity, various non-destructive test methods such as radiographic test, ultrasonic test and eddy current are used in the industrial field. However, these methods have restrictions that defect detection is possible after the crack growth. For this reason, acoustic emission testing(AET) is becoming one of powerful inspection methods, because AET has an advantage that possible to monitor the structure continuously. Generally, every mechanism that affects the integrity of the structure or equipment is a source of acoustic emission signal. Therefore the noise filtering is one of the major works to the almost AET researchers. In this study, acoustic emission signal was collected from the pipes which were in the successive thermal fatigue cycles. The data were filtered based on the results from previous experiments. Through the data analysis, the signal characteristics to distinguish the effective signal from the noises for the TFC were proven as the waveform difference. The experiment results provide preliminary information for the acoustic emission technique to the continuous monitoring of the structure failure detection.

A Study of the Acoustic Microscope System by Large Aperture Probe (대구경 탐촉자를 이용한 초음파 현미경 시스템 연구)

  • Cho, Yong-Sang;Kim, Jae-Hoon
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.23 no.5
    • /
    • pp.475-479
    • /
    • 2003
  • Traditional ultrasonic evaluation to detect micro/small surface cracks is the pulse-echo technique using the normal immersion transducer with high frequency, or the angle beam transducer with surface wave. It is difficult to make the automatic ultrasonic system that is to detect micro and small surface crack and position on the large structure like steel and ceramic rolls, because of the huge data of inspection and the ambiguous position data of transducer. The aim of this study using the high precision scanning acoustic microscope with 10MHz large aperture transducer was to display the real time A, B, C-scan for the automatic ultrasonic system in order to detect the existence and position of surface crack. The ultrasonic method with large aperture transducer was improved the scanning time and speed over 10times faster than traditional methods.