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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
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Volume & Issues
Volume 20, Issue 6 - Dec 2000
Volume 20, Issue 5 - Oct 2000
Volume 20, Issue 4 - Aug 2000
Volume 20, Issue 3 - Jun 2000
Volume 20, Issue 2 - Apr 2000
Volume 20, Issue 1 - Feb 2000
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Modeling of Radiation Beams from Ultrasonic Transducers in a Single Medium
Song, Sung-Jin ; Kim, Hak-Joon ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 91~101
Modeling of radiation beam from ultrasonic transducers has been investigated extensively, since it is one of the most important, fundamental issues that have great influence on the accuracy of an ultrasonic measurement model. Here, three popular radiation models, namely the Rayleigh-Sommerfeld integral model, the boundary diffraction wave model and the edge element model, are discussed briefly, and the radiation beam fields from ultrasonic transducers with planar, circular and rectangular cross-sections are calculated using these three models. Then, the accuracy and the time-efficiency of these methods are compared based on the calculation results.
Analysis of Scattered Fields Using High Frequency Approximations
Jeong, Hyun-Jo ; Kim, Jin-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 102~109
This paper describes two different theories used to model the scattering of ultrasound by a volumetric flaw and a crack-like flaw. The elastodynamic Kirchhoff approximation (EKA) and the geometrical theory of diffraction (GTD) are applied respectively to a cylindrical cavity and a semi-infinite crack. These methods are known as high frequency approximations. The 2-D elastodynamic scattering problems of a plane wave incident on these model defects are considered and the scattered fields are expressed in terms of the reflection and diffraction coefficients. The ratio of the scattered far field amplitude to the incident wave amplitude is computed as a function of the angular location and compared with the boundary element solutions.
The Electro-Mechanical Signal Transformation of Piezo-Electric Transducer
Ahn, Tae-Won ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 110~115
The electromechanical reciprocity identity is introduced to relate the voltage at the terminals of a transducer to the acoustic wavefields scattered from the specimen. The voltage at the terminals of the transducer is expressed as an integral equation in terms of the displacement and stress of the incident and scattered waves on the closed surface enclosing the scatterer. The equation is used to relate the voltage at the terminals of an acoustic microscope's transducer to the acoustic wavefields at the interface between the specimen and the coupling fluid. The voltage calculated using the integral equation is compared with the experimental result.
Numerical Techniques for Modeling of Ultrasonic Testing - The Finite Difference and Finite Element Methods
Yim, Hyun-June ; Yoo, Seung-Hyun ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 116~129
Due to the great complexity of the physical phenomena involved in most ultrasonic nondestructive testing, the numerical method is effective in many cases of their theoretical modeling. A brief overview is provided in this paper of the numerical methods used in modeling ultrasonic nondestructive testing, with an emphasis on the finite difference and the finite element methods. The procedures of execution, special considerations required, and some previous research results of the finite difference and the finite element methods are presented, with a rather extensive list of work reported in the literature. These numerical modeling techniques for ultrasonic nondestructive testing are expected to be more reliable and more convenient, as a result of the continuing technological development of computers.
A Study on Scattered Field of Ultrasonic Wave Using the Boundary Element Method
Lee, Joon-Hyun ; Lee, Seo-Il ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 130~137
Ultrasonic technique which is one of the most common and reliable nondestructive evaluation techniques has been applied to evaluate the integrity of structures by analyzing the characteristics of signal scattered from internal defects. Therefore, the numerical analysis of the ultrasonic scattered field is absolutely necessary for the accurate and quantitative estimation of internal defects. Various modeling techniques now play an important role in nondestructive evaluation and have been employed to solve elastic wave scattering problems. Because the elastodynamic boundary element method is useful to analyze the scattered field in infinite media. it has been used to calculate the ultrasonic wavefields scattered from internal defects. In this study, a review of the boundary element method used for elastic wave scattering problems is presented and, as examples of the boundary element method, the scattered fields due to a circular cavity subjected to incident SH-wave and due to a surface-breaking crack subjected to incident Rayleigh wave are illustrated.
Modeling of Elastodynamic Problems in Finite Solid Media
Cho, Youn-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 138~149
Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi mode conversion of guided wave scattering problems. Time dependent wave forms are obtained through the inverse Fourier transformation of the numerical solutions in the frequency domain. 3D BEM program development is underway to model more practical ultrasonic wave signals. Some encouraging numerical results have recently been obtained in comparison with the analytical solutions for wave propagation in a bar subjected to time harmonic longitudinal excitation. It is expected that the presented modeling techniques for elastic wave propagation and scattering can be applied to establish quantitative nondestructive evaluation techniques in various ways.
Modeling of Ultrasonic Testing and Its Application
Song, Sung-Jin ;
Journal of the Korean Society for Nondestructive Testing, volume 20, issue 2, 2000, Pages 150~161