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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Nondestructive Testing
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Journal DOI :
The Korean Society for Nondestructive Testing
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Volume & Issues
Volume 26, Issue 6 - Dec 2006
Volume 26, Issue 5 - Oct 2006
Volume 26, Issue 4 - Aug 2006
Volume 26, Issue 3 - Jun 2006
Volume 26, Issue 2 - Apr 2006
Volume 26, Issue 1 - Feb 2006
Selecting the target year
A Simulation Tool for Ultrasonic Inspection
Krishnamurthy, Adarsh ; Mohan, K.V. ; Karthikeyan, Soumya ; Krishnamurthy, C.V. ; Balasubramaniam, Krishnan ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 153~161
A simulation program SIMULTSONIC is under development at CNDE to help determine and/or help optimize ultrasonic probe locations for inspection of complex components. SIMULTSONIC provides a ray-trace based assessment for immersion and contact modes of inspection. The code written in Visual C++ operating in Microsoft Windows environment provides an interactive user interface. In this paper, a description of the various features of SIMULTSONIC is given followed by examples illustrating the capability of SIMULTSONIC to deal with inspection of canonical objects such as pipes. In particular, the use of SIMULTSONIC in the inspection of very thin-walled pipes (with 450 urn wall thickness) is described. Ray trace based assessment was done using SIMULTSONIC to determine the standoff distance and the angle of oblique incidence for an immersion mode focused transducer. A 3-cycle Hanning window pulse was chosen for simulations. Experiments were carried out to validate the simulations. The A-scans and the associated B-Scan images obtained through simulations show good correlation with experimental results, both with the arrival time of the signal as well as with the signal amplitudes.
Application of Phase-Shifting Method in Speckle Interferomtery to Measurement of Micro-Scale Displacement
Baek, Tae-Hyun ; Kim, Myung-Soo ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 162~168
Speckle interferometry with phase-shifting method has been applied to measurement of micro-scale displacement through optical signal processing. Four-step phase-shifting method by PZT is used to measure out-of-plane displacement in spot-welded cantilever and results of optical experiments are comparable to those of FEM. Phase-shifting method using Fourier transform by PZT is applied to measurement of in-plane displacement on rectangular steel plate with a circular hole. The results of optical experiment agree well with theoretical calculation. New phase-shifting method in speckle interferometry has been implemented with a quarter wave plate. In-plane displacement of specimen is measured by the new phase-shifting method. Results of optical experiment show that the quarter wave plate can be used for phase-shifting method that is cheap and easy to use in speckle interferometry.
In-Service Identification of the Heterogeneous Zone in Petrochemical Pipelines by Using Sealed Gamma-Ray Sources
Kim, Jin-Seop ; Jung, Sung-Hee ; Kim, Jong-Bum ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 169~173
In-service diagnoses of pipeline facilities are important for a systematic maintenance of them. Field applications by using sealed gamma-ray sources
were performed to identify the heterogeneous zone in the pipelines of a distillation tower and a flare stack respectively. From the results, the heterogeneous zones in the pipelines were successfully identified. In the case of the pipeline connected to the distillation tower, a vapor pocket was detected in the fluid under hydrodynamic conditions, which could explain the reason for a decrease of the flow rate. In another case, an area with some amount of catalyst deposits was found at the bottom of the gas pipeline which was connected to the flare stack. And these findings provided important information for the process operators. Diagnosis technique by using gamma radiation sources has been proven to be an effective and reliable method for providing information on a media distribution in a facility.
Simulation and Analysis of ECT Signals Obtained at Tubesheet and Tube Expansion Area
Song, Sung-Chul ; Lee, Yun-Tai ; Jung, Hee-Sung ; Shin, Young-Kil ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 174~180
Steam generator (SG) tubes are expanded inside tubesheet holes by using explosive or hydraulic methods to be fixed in a tubesheet. In the tube expansion process, it is important to minimize the crevice gap between expanded tube and tube sheet. In this paper, absolute and differential signals are computed by a numerical method for several different locations of tube expansion inside and outside a tubesheet and signal variations due to tubesheet, tube expansion and operating frequencies are observed. Results show that low frequency is good for detecting tubesheet location in both types of signals and high frequency is suitable for sizing of tube diameter as well as the detection of transition region. Also learned is that the absolute signal is good for measuring tube diameter, while the differential signal is good for locating the top of tubesheet and both ends of the transition region. In the case of mingled anomaly with tube expansion and tubesheet, low frequency inspection is found to be useful to analyze the mixed signal.
Generation of Thermoelastic Waves by Irradiating a Metal Slab with a Line-Focused Laser Pulse
Yoo, Jae-Gwon ; Baik, S.H. ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 181~189
A 2D finite-element numerical simulation has been developed to investigate the generation of ultrasonic waves in a homogeneous isotropic elastic slab under a line-focused laser irradiation. Discussing the physical processes involved in the thermoelastic phenomena, we describe a model for the pulsed laser generation of ultrasound in a metal slab. Addressing an analytic method, on the basis of an integral transform technique, for obtaining the solutions of the elastodynamic equation, we outline a finite element method for a numerical simulation of an ultrasonic wave propagation. We present the numerical results for the displacements and the stresses generated by a line-focused laser pulse on the surface of a stainless steel slab.
Use of Time Reversal Techniques for Focusing of Ultrasonic Array Transducer Beams
Kim, Hak-Joon ; Song, Sung-Jin ; Thompson R. Bruce ; Kim, Jae-Hee ; Eom, Heung-Sup ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 190~197
For enhancement of flaw detactability using array transducers, focusing of ultrasonic waves on a target in an inhomogeneous medium or through a complex geometry is important. But focusing can be strongly degraded by geometrical distortion of field radiated by the array transducers or by sound speed fluctuations in the propagating medium. In recent years, the time reversal technique has been proposed. Thus, in this paper, we describe the basic principal of the time reversal technique for focusing. Then, the implementation results of the time reversal technique for ultrasonic inspections using bulk waves and guided waves generated by array transducers are presented.
Effects of Material Anisotropy on Ultrasonic Beam Propagation: Diffraction and Beam Skew
Jeong, Hyun-Jo ; Schmerr, W. ;
Journal of the Korean Society for Nondestructive Testing, volume 26, issue 3, 2006, Pages 198~205
The necessity of nondestructively inspecting austenitic steels, fiber-reinforced composites, and other inherently anisotropic materials has stimulated considerable interest in developing beam models for anisotropic media. The properties of slowness surface playa key role in the beam models based on the paraxial approximation. In this paper, we apply a modular multi-Gaussian beam (MMGB) model to study the effects of material anisotropy on ultrasonic beam profile. It is shown that the anisotropic effects of beam skew and excess beam divergence enter into the MMGB model through parameters defining the slope and curvature of the slowness surface. The overall beam profile is found when the quasilongitudinal(qL) beam propagates in the symmetry plane of transversely isotropic austenitic steels. Simulation results are presented to illustrate the effects of these parameters on ultrasonic beam diffraction and beam skew. The MMGB calculations are also checked by comparing the anisotropy factor and beam skew angle with other analytical solutions.