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 15, Issue 3 - Dec 1995
Volume 15, Issue 2 - Sep 1995
Volume 15, Issue 1 - Jun 1995
Volume 14, Issue 4 - Mar 1995
Selecting the target year
Nondestructive Evaluation of Adhesive Bonding Quality by Measurements of Peak Amplitude of Simulated Stress Wave
Son, Y.H. ; Lee, J.O. ; Lee, S.H. ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 357~363
Disbond size of adhesively bonded single lap and double lap joints CFRP composite specimens has been evaluated using acousto-ultrasonic(AU) technique. Frequency spectra for all specimens were obtained by measuring peak amplitude of the stress wave propagated through the bond-lines. By analyzing these frequency spectra, peak amplitude was found to be proportional to fractional bonding area and to be maxima at the fundamental and the third order higher harmonic frequencies of specimen thickness mode. The disbond size can be evaluated quantitatively and this technique can be applied to real structures if the reference specimens are prepared in advancve.
Evaluation of High Attenuation Material Using Utrasonic Wave Analysis
Nam, Young-Hyun ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 364~370
The purpose of this paper was to develop a nondestructive evaluation method of sintered material by ultrasonic method. The density distribution of sintered material becomes inhomogeneous partially because of the friction between the powder and the die during compaction. The inhomogeneity was investigated by measurement of the energy attenuation coefficient and the shift of the center frequency in the frequency spectrum of the ultrasonic reflection echo. The experimental results showed that the center frequency of reflection wave depended linearly on the density of sintered materials. However, the attenuation coefficient decreased inversely as the density increased. This study shows that the shift of the center frequency in the frequency spectrum of reflection wave can be used to a nondestructive evaluation of sintered materials.
A Study on Constitution of Plant Safety Inspection System for Measuring Joint Axial Force of High Tension Bolt
Kim, J.Y. ; Park, S.G. ; Kim, H.S. ; Kim, C.H. ; You, S. ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 371~377
By using ultrasonic waves, we obtained conclusion from the experiment for measuring joint axial force of high tension bolt. The conclusion is followed. : From the high tension bolts used at turbine of Thermoelectric Power Plant, we obtained the equation of calculating joint axial force that is
. By using IBM PC, which is inputed by the equation for calculating joint axial force of high tension bolts, we got joint axial force of high tension bolts form beam path of ultrasonic waves. Furrther, we can identify that constitution of plant safety inspection system is possible.
Directivity Analysis of Ultrasonic Wave Reflected from the Artificial Defect in Simulated Butt Welded Joint
Nam, Young-Hyun ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 378~385
The ultrasonic non-destructive testing uses the directivity of the ultrasonic pulse wave which propagates in one direction. The directivity is expressed as the relationship between the propagate direction and its sound pressure. The directivity of ultrasonic wave is closely related to determination of probe arrangement, testing sensitivity, scanning pitch and defect location and characterization. The paper measured the directivity of shear wave, which reflected from artificial defect located in weld metal zone in butt welded joint similar model made of pyrex glass by using visualization method. 2 MHz and 4 MHz angle probes were used to measure the directivity of reflection wave at the artificial defect. The directivity of shear waves reflected from the defect was different according to the probe position and the shape of butt welded joint. The difference of directivity of reflection wave was existed between 2 MHz and 4 MHz angle probes. The angle of reflection wave became equal to angle of incidence as increase of the height of excess metal.
Normalization of the Misaligned Moire Pattern Using Fourier Transform
Park, T.W. ; Morimoto, Y. ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 386~394
The fringes developed by misalignment, an application of Moire method measuring small deformation of specimen, was transformed to frequency function. After that, theory of normalization was applied to derive the equations explaining the relation of the deformation and Moire fringes. Above all, the equations were produced to explain the rotation and increasing of fringes. In addition to that, the relation of fringe number and strain was illustated with the equations deduced from frequency function and geometrical method respectively. These two expressions were more effective than the used ones owing to the one can accommodate the other.
An Ultrasonic Pattern Recognition Approach to Welding Defect Classification
Song, Sung-Jin ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 395~406
Classification of flaws in weldments from their ultrasonic scattering signals is very important in quantitative nondestructive evaluation. This problem is ideally suited to a modern ultrasonic pattern recognition technique. Here brief discussion on systematic approach to this methodology is presented including ultrasonic feature extraction, feature selection and classification. A stronger emphasis is placed on probabilistic neural networks as efficient classifiers for many practical classification problems. In an example probabilistic neural networks are applied to classify flaws in weldments into 3 classes such as cracks, porosity and slag inclusions. Probabilistic nets are shown to be able to exhibit high performance of other classifiers without any training time overhead. In addition, forward selection scheme for sensitive features is addressed to enhance network performance.
New Requirements for Inservice Inspection of Nuclear Power Plant, Components and Its Prospect
Lee, J.P. ; Choi, H.L. ;
Journal of the Korean Society for Nondestructive Testing, volume 15, issue 2, 1995, Pages 407~414