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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
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Volume & Issues
Volume 21, Issue 6 - Dec 2001
Volume 21, Issue 5 - Oct 2001
Volume 21, Issue 4 - Aug 2001
Volume 21, Issue 3 - Jun 2001
Volume 21, Issue 2 - Apr 2001
Volume 21, Issue 1 - Feb 2001
Selecting the target year
Recent Ultrasonic Guided Wave Inspection Development Efforts
Rose, Joseph L. ; Tittmann, Bernhard R. ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 371~382
The recognition of such natural wave guides as plates, rods, hollow cylinders, multi-layer structures or simply an interface between two materials combined with an increased understanding of the physics and wave mechanics of guided wave propagation has led to a significant increase in the number of guided wave inspection applications being developed each year. Of primary attention Is the ability to inspect partially hidden structures, hard to access areas, and teated or insulated structures. An introduction to some physical consideration of guided waves followed by some sample problem descriptions in pipe, ice detection, fouling detection in the foods industry, aircraft, tar coated structures and acoustic microscopy is presented in this paper. A sample problem in Boundary Element Modeling is also presented to illustrate the move in guided wave analysis beyond detection and location analysis to quantification.
Long-Range Guided Wave Inspection of Structures Using the Magnetostrictive Sensor
Kwun, He-Geon ; Kim, Sang-Young ; Light, Glenn M. ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 383~390
Long-range guided wave inspection is a new emerging technology for rapidly and globally inspecting a large area of a structure from a single test location. This paper describes a general overview of the guided wave properties and its application for long-range inspection of structures the principle and instrument system for a guided wave inspection technology called "magnetostrictive sensor (MsS)" that generates and detects guided waves electromagnetically in the material under testing, and examples of long-range guided wave inspection of structures that can be accomplished using the MsS.
Thickness Assessment of Adhesive Layer in Inhomogeneous Layer by Guided Wave
Cho, Youn-Ho ; Ham, Hyo-Sik ; Choi, Heung-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 391~397
The guided wave propagation in inhomogeneous multi-layered structures is experimentally explored based on theoretical dispersion curves. It turns out that proper selection of incident angel and frequency is critical for guided wave generation in multi-layered structures. Theoretical dispersion curves greatly depend on adhesive zone thickness, layer thickness and material properties. It was possible to determine the adhesive zone thickness of an inhomogeneous multi-layered structure by monitoring experimentally the change of dispersion curves.
Evaluation of Size for Crack around Rivet Hole Using Lamb Wave and Neural Network
Choi, Sang-Woo ; Lee, Joon-Hyun ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 398~405
The rivet joint has typical structural feature that can be initiation site for the fatigue crack due to the combination of local stress concentration around rivet hole and the moisture trapping. From a viewpoint of structural assurance, it is crucial to evaluate the size of crack around the rivet holes by appropriate nondestructive evaluation techniques. Lamb wave that is one of guided waves, offers a more efficient tool for nondestructive inspection of plates. The neural network that is considered to be the most suitable for pattern recognition has been used by researchers in NDE field to classify different types of flaws and flaw sizes. In this study, clack size evaluation around the rivet hole using the neural network based on the back-propagation algorithm has been tarried out by extracting some features from the ultrasonic Lamb wave for A12024-T3 skin panel of aircraft. Special attention was paid to reduce the coupling effect between the transducer and the specimen by extracting some features related to time md frequency component data in ultrasonic waveform. It was demonstrated clearly that features extracted from the time and frequency domain data of Lamb wave signal were very useful to determine crack size initiated from rivet hole through neural network.
Guided Wave Mode Selection and Flaw Detection for Long Range Inspection of Polyethylene Coated Steel Gas Pipes
Song, Sung-Jin ; Park, Joon-Soo ; Shin, Hyeon-Jae ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 406~414
Ultrasonic guided waves were explored to apply them to the long range inspection of polyethylene coated steel gas pipes. The steel pipes have such dimensions as 190.7mm inside diameter and 5.3mm thickness. The outside surface of the pipe is coated by a polyethylene layer of
thickness. Non-axisymmetric guided waves were excited on the outside surface of the polyethylene coated pipe by using a 0.5MHz transducer with a variable angle shoe. Frequency and phase velocity tuning was used to find optimum guided wave modes for the inspection. The dispersive characteristics of the modes were analyzed in time-frequency representation obtained by short time Fourier transforms. Sample results were presented for artificial defects such as wall thinning and hole.
Degradation Estimation of 2.25Cr-1Mo Steel by Ultrasonic Guided Wave
Park, Ik-Keun ; Park, Un-Su ; Lee, Sang-Young ; Kwun, Sook-In ; Cho, Youn-Ho ; Yoon, Seung-Hyun ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 415~424
The destructive method is reliable and widely used for the estimation of material degradation but, it have time-consuming and a great difficulty in preparing specimens from in-service industrial facilities. Therefore, the estimation of degraded structural materials by nondestructive evaluation is strongly desired. In this paper, the use of guided wave was suggested for the evaluation on thermally damaged 2.25Cr-1Mo steel as an alternative way to compensate for limitations of fracture tests. The observation of microstructure variations of the material including carbide precipitation increase and spheroidization near grain boundary was conducted and the correlation with the guided wave features such as energy loss ration and group velocity changes was investigated. Through this study, the feasibility of ultrasonic guided wave evaluation for thermally damaged materials was explored.
Assessment of Fatigue Damage of Adhesively Bonded Composite -Metal Joints by Acousto-Ultrasonics and Acoustic Emission
Kwon, Oh-Yang ; Lee, Kyung-Joo ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 425~433
A correlation between fatigue damage and acousto-ultrasonic (AU) parameters has been obtained from signals acquired during fatigue loading of the single-lap joints of a carbon-fiber reinforced plastic (CFRP) laminates and A16061 plate. The correlation showed an analogy to those representing the stiffness reduction
of polymer matrix composites by the accumulation of fatigue damage. This has been attributed to the transmission characteristics of acoustic wave energy through bonded joints with delamination-type defects and their influence on the change of spectral content of AU signals. Another correlation between fatigue cycles and the spectral magnitude of acoustic emission (AE) signals has also been found during the final stage of fatigue loading. Both AU and AE can be applied almost in real-time to monitor the evolution of damage during fatigue loading.
Fabrication and Evaluation of Piezoelectric Torsional Transducers
Kwon, Oh-Soo ; Kim, Jin-Oh ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 434~438
Piezoelectric torsional transducers have been fabricated to generate torsional waves in a rod. The principle of generating torsional wane is based on the use of the circumferential shear motion derived by axial voltage exerted on the piezoelectric disk poled in the circumferential direction. The natural frequency or the piezoelctric torsional dish has been reduced by fabricating Langevin-type torsional transducers. The natural frequecies of the fabricated transducers have been measured and have shown good agreement with the characteristics predicted by analysis.
A Study on the High Frequency Ultrasonic Attenuation Characterization in Artificially Aging Degraded 2.25Cr-1Mo Steel
Park, Ik-Keun ; Park, Un-Su ; Kim, Chung-Seok ; Kim, Hyun-Mook ; Kwun, Sook-In ; Byeon, Jai-Won ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 439~445
The destructive method is reliable and widely used lot the estimation of material degradation but, it have time-consuming and a great difficulty in preparing specimens from in-service industrial facilities. Therefore, the estimation of degraded structural materials used at high temperature by nondestructive evaluation such as electric resistance method, replica method, Barkhausen noise method, electro-chemical method and ultrasonic method are strongly desired. Ultrasonic nondestructive evaluation technique has been reported good to attain efficiency of measurement, high sensitivity of measurement, and rapidity and reliability of result interpretation. In this study, it was verified experimentally the feasibility of the evaluation of degraded 2.25Cr-1Mo steel specimens which were prepared by the isothermal aging heat treatment at
by high frequency longitudinal wave method investigating the change of attenuation coefficient by FFT analysis and wavelet transform. Because of carbide precipitation increase and spheroidization near grain boundary of microstructure to aging degradation, attenuation coefficient had a tendency to increase as degradation proceeded. It was identified possibly to evaluate degradation using the characteristics of high-frequency ultrasonics. Frequency dependence of ultrasonic attenuation coefficient to aging degradation appeared large, which made sure that attenuation coefficient is an important parameter for evaluation of aging degradation.
Understanding and Application of Ultrasonic Guided Waves
Cho, Youn-Ho ;
Journal of the Korean Society for Nondestructive Testing, volume 21, issue 4, 2001, Pages 446~460