Go to the main menu
Skip to content
Go to bottom
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 25, Issue 6 - Dec 2005
Volume 25, Issue 5 - Oct 2005
Volume 25, Issue 4 - Aug 2005
Volume 25, Issue 3 - Jun 2005
Volume 25, Issue 2 - Apr 2005
Volume 25, Issue 1 - Feb 2005
Selecting the target year
Virtual Reality Presentation for Nondestructive Evaluation of Rebar Corrosion in Concrete based on Inverse BEM
Kyung, Je-Woon ; Yokota, Masaru ; Leelalerkiet, V. ; Ohtsu, Masayasu ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 157~162
In order to evaluate the corrosion of reinforcing steel-bars (rebar) in concrete, a nondestructive evaluation by the half-cell potential method is currently applied. In this study, potentials measured on a concrete surface are compensated into those on the concrete-rebar interface by the inverse boundary element method (IBEM). Because these potentials are obtained three-dimensionally (3-D), 3-D visualization is desirable. To this end, a visualization system has been developed by using VRML (Virtual Reality Modeling Language). As an application, results of a reinforced concrete (RC) slab with corroded rebars are visualized and discussed.
Application of a Modular Multi-Gaussian Beam Model to Ultrasonic Wave Propagation with Multiple Interfaces
Jeong, Hyun-Jo ; Park, Moon-Cheol ; Schmerr Lester W. ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 163~170
A modular Gaussian beam model is developed to simulate some ultrasonic testing configurations where multiple interfaces are involved. A general formulation is given in a modular matrix form to represent the Gaussian beam propagation with multiple interfaces. The ultrasonic transducer fields are modeled by a multi-Gaussian beam model which is formed by superposing 10 single Gaussian beams. The proposed model, referred to as "MMGB" (modular multi-Gaussian beam) model, is then applied to a typical contact and angle beam testing configuration to predict the output signal reflected from the corner of a vertical crack. The resulting expressions given in a modular matrix form are implemented in a personal computer using the MATLAB program. Simulation results are presented and compared with available experimental results.
Application of Phase-shifting Method using fourier Transform to Measurement of In-plane Displacement by Speckle Interferometry
Kim, Myung-Soo ; Baek, Tae-Hyun ; Morimoto, Yoshiharu ; Fujigaki, Motoharu ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 171~177
Phase-shifting method using Fourier transform (PSM/FT) has been applied to measurement of in-plane displacement of a specimen. Thirty-two interference fringe patterns each of which has different phase of
radian have been gathered from a specimen with in-plane displacement. Low-pass filtering by 2-D Fourier transform is used to suppress spatial noise of the fringe patterns.
Fourier transform for PSM/FT is performed by use of the low-pass filtered 32 fringe patterns. Two kinds of specimens are used for experiment. One is a rectangular steel plate and the other one is a rectangular steel plate containing a circular hole at the center. In-plane displacement of each specimen is measured by PSM/FT, and calculated by finite element method (ANSYS) for comparison. The results are quite comparable, so that PSM/FT can be applied to measurement of in-plane displacement.
Vibration-based Identification of Directional Damages in a Cylindrical Shell
Kim, Sung-Hwan ; Oh, Hyuk-Jin ; Lee, U-Sik ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 178~188
This paper introduces a structural damage identification method to identify 4he multiple directional damages generated within a cylindrical shell by using the measured frequency response function (FRF). The equations of motion for a damaged cylindrical shell are derived. by using a theory of continuum damage mechanics in which a small material volume containing a directional damage is represented by the effective orthotropic elastic stiffness. In contrast with most existing vibration-based structural damage identification methods which require the modal Parameters measured in both intact and damaged states, the present method requires only the FRF-data measured at damaged state. Numerically simulated damage identification tests are conducted to verify the feasibility of the Proposed structural damage identification method.
Ultrasonic NDE Classifications with the Gradient Descent Method and Synthetic Aperture Focusing Technique
Kim, Dae-Won ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 189~200
Ultrasonic inspection methods are widely used for detecting flaws in materials. One of the more popular methods involves the extraction of an appropriate set of features followed by the use of a neural network for the classification of the signals in the feature space. This paper describes an approach which uses LMS method to determine the coordinates of the ultrasonic probe followed by the use of SAFT to estimate the location of the ultrasonic reflector The method is employed for classifying NDE signals from the steam generator tubes in a nuclear power plant. The classification results using this scheme for the ultrasonic signals from cracks and deposits within steam generator tubes are presented.
Comparison of Absolute and Differential ECT Signals around Tube Support Plate in Steam Generator
Shin, Young-Kil ; Lee, Yun-Tai ; Song, Myung-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 201~208
In this paper, absolute and differential eddy current signals from various defects in the steam generator tube are numerically predicted and their signal slope characteristics are investigated. The signal changes due to frequency increase are also observed. After studying signal patterns from various defects and frequencies, the analysis of mixed defect signals affected by the presence of a ferromagnetic support plate is attempted. For the signal prediction, axisymmetric finite element modeling is used and this leads us to the slope angle analysis of the signal. Results show that differential signals are useful for locating the position of a defect under the support plate, while absolute signals are easy to presume and interpret even though the effect of support plate is mixed. Combined use of these two types of signals will help us accomplish a more reliable inspection.
Evaluation of the Weldability in Spot Welding using Ultrasonic Technique
Hong, Min-Sung ; Kim, No-Hyu ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 209~214
Spot welding is the most widely used in automotive and aerospace industries. The quality of weld depends upon the size of nugget between the overlapped steel plates. Recently, the thickness of the steel plates is much thinner and hence, it introduces the smaller size of nugget. Therefore, it is necessary not only to develop the criterion to evaluate the quality of weld but also to obtain the optimal welding conditions for the better performance. In this paper, the steel plates, 0.5 mm through 1.5 mm thickness, have been spot welded at different welding conditions and the nugget sizes are examined by ultrasonic technique (C-scan type). The relationships between the nugget sizes and the weldability have been investigated. The result of ultrasonic technique shows the good agreement with that of the tensile test.
Development of Self-compensated Technique for Evaluation of Surface-breaking Crack by Using Laser Based Ultrasound
Choi, Sang-Woo ; Lee, Joon-Hyun ; Cho, Youn-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 215~221
It is required to evaluate nondestructively depth of surface-breaking cracks in structures. In this paper, the self-compensated technique by laser-based ultrasound is used to measure the depth of surface-breaking defect. Optical generation of ultrasound produces a well defined pulse with reliable frequency content. It is broad banded and suitable for measurement of attenuation and scattering over a wide frequency range. The self-calibrated signal transmission data of surface wave shows good sensitivity as a practical tool far assessment of surface-breaking defect depth. It is suggested that the relationship between the signal transmission and crack depth can be used to predict the surface-breaking crack depths in structures.
A Numerical Analysis on Elastodynamic Dispersion Phenomena of Composite Pipes
Cho, Youn-Ho ; Lee, Chong-Myong ; Rose Joseph L. ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 222~227
An efficient technique fur the calculation of guided wave dispersion curves in composite pipes is presented. The technique uses a forward-calculating variational calculus approach rather than the guess and iterate process required when using the more traditional partial wave superposition technique. The formulation of each method is outlined and compared. The forward-calculating formulation is used to develop finite element software for dispersion curve calculation. Finally, the technique is used to calculate dispersion curves for several structures, including an isotropic bar, two multi-layer composite bars, and a composite pipe.
Development of Performance Demonstration Programs for Eddy Current Data Analysis
Cho, Chan-Hee ; Nam, Min-Woo ; Yang, Seung-Han ; Yang, Dong-Soon ; Lee, Hee-Jong ;
Journal of the Korean Society for Nondestructive Testing, volume 25, issue 3, 2005, Pages 228~232
The Korea Electric Power Research Institute (KEPRI) has developed performance demonstration programs for non-destructive testing personnel who analyze ECT(eddy current testing) data for steam generator tubing since 2001 The purpose of these performance demonstration programs is to ensure a uniform knowledge and skill level of data analysts and contribute to safe operation of nuclear power plants. Many changes have occurred in non-destructive testing of steam generator tubing such as inspection scope, plugging criteria and qualification requirements. According to the Notice 2004-13 revised by the Ministry of Science and Technology (MOST), the analyst for steam generator tubing shall be qualified as the qualified data analyst (QDA), and the site specific performance demonstration (SSPD) program shall be implemented. KEPRI developed these performance demonstration programs and they are being successfully implemented. The analyst's performance is expected to be improved by the implementation of these programs.