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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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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 28, Issue 6 - Dec 2008
Volume 28, Issue 5 - Oct 2008
Volume 28, Issue 4 - Aug 2008
Volume 28, Issue 3 - Jun 2008
Volume 28, Issue 2 - Apr 2008
Volume 28, Issue 1 - Feb 2008
Selecting the target year
Analysis of the O-Ring Deformation Behavior by the Computed Tomography
Kim, Dong-Ryun ; Kim, Jae-Hoon ; Park, Sung-Han ; Lee, Hwan-Gyu ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 1~8
The object of this study is to develop the examination technique for measuring the O-ring deformation behavior under the pressure and the squeezed condition simultaneously. The O-ring deformation measuring device in which two grooves were dug to insert the two O-rings was manufactured to be not deformed under the high pressure and the 1 mm and 0.1 mm gap were designed to measure the extrusion lengths under the internal pressure. The beam hardening correction, the histogram analysis and the dead zone correction were executed to exactly measure the shape of O-ring deformation and the lengths of the O-ring deformation were measured by the LSF and the ERF. The computed tomography applied the pressure of 0, 1.378, 4.902, 9.804, 15.692 MPa at 22.3% squeezed condition and the expanded diameter, contact length and extrusion depth were measured in each pressure. The shape of O-ring deformation was evaluated by the FEM to verify the results of measuring by the computed tomography and the area of O-ring was mutually compared to the area measured by the computed tomography.
Development of New ECT Probe Separating the Permebility Variation Signal in the SG Tube
Park, Duck-Gun ; Ryu, Kwon-Sang ; Lee, Jeong-Kee ; Son, De-Rac ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 9~15
A new ECT probe to separate the ECT signal distortion due to PVC (permeability variation clusters) and ordinary defects created in SG tubes has been developed. The hystersis loops of PVC which are extracted from retired SG (steam generator) tubes of Kori-1 NNP were measured. The tensile tests were performed to identify the mechanism of PVC creation. The conditions detecting the PVC created in 56 tubes were investigated using computer simulation, and the signal processing circuits were inserted in the probe for the digital signal transmission. The new Probe can measure and separate the PVC signal which is created in the SG tubes, and also measures the defects in Ni-sleeving part of SG tubes. furthermore the new ECT probe can measure the defects as fast as bobbin probe, and enhance the testing speed as well as reliability of the defect detection of SG tubes.
A Study on Properties of a Near-Field Microwave Microscope Using a Waveguide Resonator
Kim, Hyun ; Kim, Song-Hui ; Kim, Joo-Young ; Lee, Kie-Jin ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 16~24
Near-field scanning microwave microscope (NSMM) has been used to characterize the electromagnetic properties of samples based on a cavity perturbation technique. We used a NSMM using a waveguide cavity to couple a metallic probe tip as a point like evanescent field emitter. We explained the quality of our NSMM system by applying the cavity perturbation theory. First, to make a shape perturbation, we inserted linear and loop probes in the waveguide resonator. To check up electric and magnetic field distribution inside the waveguide resonator by shape perturbation, we confirmed the field distribution by using a HFSS simulation. Second, to make material perturbation, we located a dielectric sample in front of the probe tip and measured reflection coefficient
. We found that the resonance frequency
was changed linearly as the dielectric constant of resonator
Low-Energy Sealed Source for Nondestructive Testing Applications Utilizing HANARO
Son, K.J. ; Hong, S.B. ; Jang, K.D. ; Han, H.S. ; Park, U.J. ; Lee, J.S. ; Seo, K.S. ; Han, I.S. ; Cho, W.K. ; Lee, S.S. ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 25~32
] industrial NDT sealed sources were developed by using
pellets as the target and demonstrated for their performance. To produce the pellets, optimal compacting and sintering conditions were determined experimentally. Source holders for
were designed and fabricated. After assembling an active source produced from HANARO with the developed source holder, a demonstration experiment was performed to compare the quality of the radiographs from
and soft X-rays. This demonstration study showed that the developed
produced better radiographs than
for a carbon steel with less than a 4 mm thickness.
Quantitative Comparison of Out-of-Plane Deformation Measured by Dual-Function Interferometer System
Kim, Kyoung-Suk ; Chang, Ho-Seob ; Lee, Seung-Seok ; Jung, Hyun-Chul ; Kwag, Jae-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 33~39
Dual-function interferometer is an interferometer that has all features of ESPI (electronic speckle pattern interferometry) and shearography in one interferometer setup. The deformatiou of an object is directly obtained by ESPI while the slope of the deformation of an object is obtained by shearography. If the result of shearography is divided by shearing amount and integrated by numerical analyzing, then finally the reconstructed deformation of an object that is the same as the results directly obtained by ESPI can be measured by shearography. In this study, rubber and alruminum plates are used as specimen and its out-of-plane deformation is measured by ESPI and shearography setup of the dual-function interferometer. Each of the results obtained by ESPI and shearography is compared by using numerical integration to the result of shearography. From this study, it is confirmed that the reconstructed deformation results obtained by numerical integration good agree with the results obtained by ESPI.
Measurement of Longitudinal and Transverse Wave Speed in Solid Materials Using Immersion Ultrasonic Testing
Shin, Yo-Sub ; Yoon, Yeo-Ho ; Kim, Young-H. ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 40~45
Immersion ultrasonic testing (UT) was used to determine elastic moduli of solid materials instead of the widely-used contact UT method. Conventionally, immersion UT is only used for determining the longitudinal wave speed. However, in this research, transverse wave speed was measured through finding transverse wave echoes caused by mode-conversion at material's boundary. Also, even in the cases when wave speeds could not be determined due to unknown thickness, Poisson's ratio was able to be calculated from the ratio of longitudinal and transverse wave speeds. This technique was verified for several materials, and it was found that higher accuracy was obtained by immersion UT method for materials either with relatively high wave speed or with relatively small Poisson's ratio. This technique thus will be suitable fur ceramics or high strength materials.
Evaluation of Internal Defect of Composite Laminates Using A Novel Hybrid Laser Generation/Air-Coupled Detection Ultrasonic System
Lee, Joon-Hyun ; Lee, Seung-Joon ; Byun, Joon-Hyung ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 46~53
Ultrasonic C-scan technique is one of very popular techniques being used for detection of flaws in polymer matrix composite(PMC). However, the application of this technique is very limited for evaluation of defects in PMC fabricated by the automated fiber placement process. The purpose of this study is to develop a novel ultrasonic hybrid system based on nondestructive and non-contact ultrasonic techniques for evaluation of delamination in carbon/epoxy and carbon/PPS composite laminates. It was shown that the newly developed ultrasonic hybrid system based on dual air-coupled pitch-catch technique with ultrasonic scattering reflection concept could provide excellent image with higher resolution of delamination in PMC compared with the conventional pitch-catch method. It is expected that this ultrasonic hybrid technique can be applied for on-line inspection of flaws in PMC during the fabrication process.
Time Reversa1 Reconstruction of Ultrasonic Waves in Anisotropic Media
Jeong, Hyun-Jo ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 54~58
Time reversal (TR) of body waves in fluids and isotropic solids has been used in many applications including ultrasonic NDE. However, the study of the TR method for anisotropic materials is not well established. In this paper, the full reconstruction of the input signal is investigated for anisotropic media using an analytical formulation, called a modular Gaussian beam (MGB) model. The time reversal operation of this model in the frequency domain is done by taking the complex conjugate of the Gaussian amplitude and phase received at the TR mirror position. A narrowband reference signal having a particular frequency and number of cycles is then multiplied and the whole signal is inverse Fourier transformed. The original input signal is seen to be fully restored by the TR process of MGB model and this model can be more generalized to simulate the spatial and temporal focusing effects due to TR process in anisotropic materials.
Reconstruction of Dispersive Lamb Waves in Time Plates Using a Time Reversal Method
Jeong, Hyun-Jo ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 59~63
Time reversal (TR) of nondispersive body waves has been used in many applications including ultrasonic NDE. However, the study of the TR method for Lamb waves on thin structures is not well established. In this paper, the full reconstruction of the input signal is investigated for dispersive Lamb waves by introducing a time reversal operator based on the Mindlin plate theory. A broadband and a narrowband input waveform are employed to reconstruct the
mode of Lamb wave propagations. Due to the frequency dependence of the TR process of Lamb waves, different frequency components of the broadband excitation are scaled differently during the time reversal process and the original input signal cannot be fully restored. This is the primary reason for using a narrowband excitation to enhance the flaw detectability.
Comparison of TOFD and Radiographic Testing for a Mock-up Specimen
Kim, Chung-Jick ; Jeon, Jong-Gun ; Kim, Jin-Taek ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 1, 2008, Pages 64~69
In order to detect the internal defects which occur in welding parts of pressure vessel and structures, radiographic testing and ultrasonic testing is applied. However, because of the risks of radiation exposure and film processing, radiographic testing takes a relatively long time to verify the test results and it has affected in the production process. Typically, the manual ultrasonic testing is not easy to reproduce the result and it is highly dependent on the tester's skills. The TOFD technique, one of the automatic ultrasonic testings is spreading alternatively. This research describes the comparing test results by applying radiographic testing and TOFD technique to a mock-up specimen incruding the flaws. The TOFD technique will contribute to improve the objective reliability of the ultrasonic technique.