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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society for Nondestructive Testing
Journal Basic Information
Journal DOI :
The Korean Society for Nondestructive Testing
Editor in Chief :
Volume & Issues
Volume 10, Issue 2 - Nov 1990
Volume 10, Issue 1 - May 1990
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Development of Eddy Current Technique for Reactor In-Core Flux Thimble Wear
Park, S.S. ; Jang, Y.Y. ; Yim, C.Y. ; Park, K.H. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 15~22
Since in-core flux thimble tube wear the due to flow-induced vibration could degrade the integrity of nuclear reactor, the effective detection and interpretation of the wear is important. In order to establish an inspection technique for thimble tubes, an eddy current experiment was performed to determine the optimum test frequency, defect sensitivity and evaluation accuracy. Eddy current probes were designed and fabricated with a theory. Specimens with artificial defects were fabricated using electro discharge machining method. The results from inspection technique developed and on-site inspection showed good applicability.
Discrimination of Acoustic Emission Signals using Pattern Recognition Analysis
Joo, Y.S. ; Jung, H.K. ; Sim, C.M. ; Lim, H.T. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 23~31
Acoustic Emission(AE) signals obtained during fracture toughness test and fatigue test for nuclear pressure vessel material(SA 508 cl.3) and artificial AE signals from pencil break and ultrasonic pulser were classified using pattern recognition methods. Three different classifiers ; namely Minimum Distance Classifier, Linear Discriminant Classifier and Maximum Likelihood Classifier were used for pattern recognition. In this study, the performance of each classifier was compared. The discrimination of AE signals from cracking and crack surface rubbing was possible and the analysis for crack propagation was applicable by pattern recognition methods.
A Development of Computer Controlled 5 Axis Ultrasonic Testing System
Kim, Y.S. ; Kim, J.G. ; Park, J.C. ; Kim, N.I. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 32~37
A computer controlled 5 axis ultrasonic testing system is developed in order to detect flaws in special parts with complex shape. The various kinds of ultrasonic test can be performed automatically using computer program which was developed by DHI(Daewoo Heavy Industries Ltd.). By use of this computer program, the detector location can be programed and the amplitude signal of echo can be processed digitally. The test results can be plotted graphically on a high resolution display monitor in real time base. The test data can be also saved in magnetic memory devices(HDD or FDD) as well as in the form of hard copy through color printer. The computer software contains c- scan, c+a scan processing programs as well as statistical analysis for test data.
Fiber Orientation Determination of CFRP Composites using CODF Concept
Lee, S.S. ; Ahn, B.Y. ; Lee, J.R. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 38~42
The specific strength of the fiber reinforced composite material is closely related to the anisotropy of the material. For the quantitative characterization of the anisotropy in the composite material, applied was CODF concept which was extensively used in the metallic material. As the results, the anisotropy of the material could be quantitatively analysed from the measurement of the phase velocities of the angular dependent
A Study on the Microdefect Detection of Semiconductor Package by Digital Ultrasonic Image Processing
Kim, J.Y. ; Han, E.K. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 43~49
Ultrasonic testing is one of the most useful NDT method for detection of microdefect in the opaque materials. Recently, many applications of the ultrasonic techniques have been extended widely in the new field like electron is and advanced materials. From the result of the experiment, we have hardly found out a crack in the internal parts of the resin and a delamination between chip and resin because of poor performance of the system.
Thermal Inspection of GFRP using Liquid Crystal
Kim, Y.H. ; Kwon, O.Y. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 50~55
Flaws in GFRP(Glass Fiber Reinforced Plastics) were thermally detected using cholesteric liquid crystals. Presence of flaws changes the thermal conductivity of GFRP, and disturbs heat flow. When a uniform heat source is applied, the surface temperature of flawed region is different from that of sound region. The surface temperature distributions were measured by thermo-optic properties of liquid crystal. Since the colors of liquid crystal indicate temperature distribution of GFRP surface, the thermal disturbance by flaws could be detected. The locations of flaws in GFRP could be determined from the distribution of liquid crystal colors.
A Study on the Detection of Surface Acoustic Waves by Noncontact Method
You, I.H. ; Yoon, J.S. ; Kim, D.I. ;
Journal of the Korean Society for Nondestructive Testing, volume 10, issue 2, 1990, Pages 56~62
Surface Acoustic Waves(SAW) are generated on silicon wafer and
substrate and are detected by noncontact method. As wave sources two kinds of transducers are used : the wedge-type of 20.0 MHz and fabricated Interdigital Transducer(IDT) of 20.8 MHz. SAW are modulated by the optical chopper frequency and are syncronized with a laser beam. In signal processing, intensity variations of light due to the intensity of SAW are analyzed using lock- in amplifier. From the results, corresponding to the applied input power, the intensity variations of a deflected light by corrugations on the substrates are increased and saturation phenomenon is observed.