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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 32, Issue 6 - Dec 2012
Volume 32, Issue 5 - Oct 2012
Volume 32, Issue 4 - Aug 2012
Volume 32, Issue 3 - Jun 2012
Volume 32, Issue 2 - Apr 2012
Volume 32, Issue 1 - Feb 2012
Selecting the target year
Analysis of Acoustic Emission Signal for Vehicle CNG Tank Using Wideband Transducer
Jee, Hyun-Sup ; Lee, Jong-O ; Ju, No-Hoe ; So, Cheal-Ho ; Lee, Jong-Kyu ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 1~6
DOI : 10.7779/JKSNT.2012.32.1.001
This study is damage evaluation for CNG fuel tank during the burst test through the analysis of acoustic emission signals. Kaiser effect until the pressure 420 bar appears, but More than 420 bar by the creep effect appears significantly damaged vessels, and 480 bar pressure, the Kaiser effect of the rising phase was missing. Resonant transducer at 540 bar than 480 bar decreased activity such as energy and count Continually, but increased wideband transducer. In addition, through the rise time or frequency analysis of composite pressure vessels in order to observe the damage mechanisms wideband transducer is more effective than resonant transducer.
Study on NDT Fault Diagnosis of the Ball Bearing under Stage of Abrasion by Infrared Thermography
Seo, Jin-Ju ; Hong, Dong-Pyo ; Kim, Won-Tae ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 7~11
DOI : 10.7779/JKSNT.2012.32.1.007
For fault detection about the abrasion stage of rotational machineries under the dynamic loading conditions unlike the traditional diagnosis method used in the past decade, the infrared thermographic method with its distinctive advantages in non-contact, non-destructive, and visible aspects is proposed. In this paper, by applying a rotating deep-grooved ball bearing, passive thermographic experiments were conducted as an alternative way to proceeding the traditional fault monitoring on spectrum analyzer. As results, the thermographic experiment was compared with the traditional vibration spectrum analysis to evaluate the efficiency of the proposed method. Based on the results obtained as NDT, the temperature characteristics and abnormal fault detections of the ball bearing according to the abrasion stage were analyzed.
Determination of an Test Condition for IR Thermography to Inspect a Wall-Thinning Defect in Nuclear Piping Components
Kim, Jin-Weon ; Yun, Won-Kyung ; Jung, Hyun-Chul ; Kim, Kyeong-Suk ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 12~19
DOI : 10.7779/JKSNT.2012.32.1.012
This study conducted infrared (IR) thermography tests using pipe and plate specimens with artificial wall-thinning defects to find an optimal condition for IR thermography test on the wall-thinned nuclear piping components. In the experiment halogen lamp was used to heat the specimens. The distance between the specimen and the lamp and the intensity of halogen lamp were regarded as experimental parameter. When the distance was set to 1~2 m and the lamp intensity was above 60 % of full power, a single scanning of IR thermography detected all artificial wall-thinning defects, whose minimum dimension was
, d/t=0.5, and
, within the pipe of 500 mm in length. Regardless of the distance between the specimen and the lamp, the image of wall-thinning defect in IR thermography became distinctive as the intensity of halogen lamp increased. The detectability of IR thermography was similar for both plate and pipe specimens, but the optimal test condition for IR thermography depended on the type of specimen.
Assessment of Plastic Deformation in Al6061 Alloy using Acoustic Nonlinearity of Laser-Generated Surface Wave
Kim, Chung-Seok ; Nam, Tae-Hyung ; Choi, Sung-Ho ; Jhang, Kyung-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 20~26
DOI : 10.7779/JKSNT.2012.32.1.020
The objective of this study is to assess plastic deformation in aluminium alloy by acoustic nonlinearity of laser-generated surface waves. A line-arrayed laser beam made by high-power pulsed laser and mask slits is utilized to generate the narrowband surface wave and the frequency characteristics of laser-generated surface waves are controlled by varying the slit opening width and slit interval of mask slits. Various degrees of tensile deformation were induced by interrupting the tensile tests so as to obtain aluminum specimens with different degrees of plastic deformation. The experimental results show that the acoustic nonlinear parameter of a laser-generated surface wave increased with the level of tensile deformation and it has a good correlation with the results of micro-Vickers hardness test and electron backscatter diffraction (EBSD) test. Consequently, acoustic nonlinearity of laser-generated surface wave could be potential to characterize plastic deformation of aluminum alloy.
Fringe Analysis around an Inclined Crack Tip of Finite-Width Plate under Tensile Load by Photoelastic Phase-Shifting Method
Li, Weizheng ; Baek, Tae-Hyun ; Hong, Dong-Pyo ; Lee, Byung-Hee ; Seo, Jin ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 27~33
DOI : 10.7779/JKSNT.2012.32.1.027
Photoelasticity is a technique of experimental methods and has been widely used in various domains of engineering to determine the stress distribution of structures. Without complicated mathematical formulation, this technique can conveniently provide a fairly accurate whole-field stress analysis for a mechanical structure. Here, stress distribution around an inclined crack tip of finite-width plate is studied by 8-step phase-shifting method. This method is a kind of photoelastic phase-shifting techniques and can be used for the determination of the phase values of isochromatics and isoclinics. According to stress-optic law, the stress distribution could be obtained from fringe patterns. The results obtained by polariscope arrangement combined with 8-step method and ABAQUS FEM simulations are compared with each other. Good agreement between them shows that 8-step phase-shifting method is reliable and can be used for determination of stress by experiment.
Effect of Bonding Layer on Guided Wave Mode Behavior in FRP Plate Bonded on Concrete
Lee, Yong-Ju ; Shin, Sung-Woo ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 34~40
DOI : 10.7779/JKSNT.2012.32.1.034
In this study, effects of bonding agent, e.g. epoxy, on the behavior of fundamental guided wave modes propagated in FRP plate bonded on a concrete, are investigated. Global matrix model of multilayered FRP-epoxy-concrete system was constructed to obtain the velocity and attenuation dispersion curves of the fundamental A0 and S0 modes. Two variables, thickness and elastic modulus of epoxy layer, were considered in the dispersion analysis. It was found that both the thickness and the elastic modulus of epoxy layer greatly affect the phase velocity and attenuation of S0 mode while those are negligible for A0 mode. Based on the results, it was concluded that S0 mode is more effective than A0 mode for bonding condition assessment for FRP plate bonded concrete.
Measurement of Elastic Constants of Thin Metallic Foil by Guided Wave Dispersion Characteristics
Lee, Dong-Jin ; Cho, Youn-Ho ; Jang, Kang-Won ; Cho, Seung-Hyun ; Ahn, Bong-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 41~46
DOI : 10.7779/JKSNT.2012.32.1.041
As the development of MEMS/NEMS structure and application technology the demand for an assessment of the mechanical properties have increased. The mechanical properties are mainly evaluated by using tensile test or ultrasonic wave measurement. However, the new technology have been developed such as nano-indentation, guided wave method because they have a limitation in case of a thin plate and thin film. In the study, the guided wave velocities are measured by electromagnetic-acoustic transducer(EMAT), the material properties of thin metallic foils are obtained using optimization process of the theoretical and experimental group velocity of guided wave. The Young's modulus obtained by the optimization process(201.6 GPa), nano-indentation(207.0 GPa) and literature value(203.7 GPa) of a
thick nickel thin plate shows good agreement within 3%.
Determination of Impact Source Location Using a Single Transducer and Time Reversal Technique
Jeong, Hyun-Jo ; Cho, Sung-Jong ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 47~55
DOI : 10.7779/JKSNT.2012.32.1.047
A structural health monitoring technique for locating impact position in a plate structure is presented in this paper. The method employs a single sensor and spatial focusing of time reversal (TR) acoustics. We first examine the TR focusing effect at the impact position and its surroundings through simulation and experiment. The imaging results of impact points show that the impact source location can be accurately estimated in any position of the plate. Compared to existing techniques for locating impact or acoustic emission source, the proposed method has the benefits of using a single sensor and not requiring material properties and geometry of structures. Furthermore, it does not depend on a particular mode of dispersive Lamb waves that is frequently used in other ultrasonic testings of plate-like structures.
Eddy Current and Ultrasonic IRIS Signal Characteristics of Reboiler Tube by Using STS 316L Calibration Specimen
Tak, Kyeong-Joo ; Kim, Byung-Il ; Gook, Jin-Seon ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 56~63
DOI : 10.7779/JKSNT.2012.32.1.056
In this study, a field applicability of reboiler tube was evaluated by comparing ECT signal with IRIS signal about wall loss rate and remaining wall thickness using worked austenite STS 316L ASME standard calibration tube. In the case of wall-loss rate, as a result, tolerance about
flat bottom hole and 10% O D groove(ECT), 80% defect and 10% O D groove(IRIS) occurred up to
. In the case of remaining wall thickness, ECT was satisfied with the both tolerance, but tolerance about 80% defect occurred up to
in IRIS. Therefore, if the IRIS is performed for interpretation of non-relevant indication and measurement of wall-loss rate after ECT, reliability is supposed to be improved.
A Study on Electrical Characteristics for Coil Winding Number Changes of Eddy Current Bobbin Coil for Steam Generator Tubes in NPPs
Nam, Min-Woo ; Kim, Cheol-Gi ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 64~70
DOI : 10.7779/JKSNT.2012.32.1.064
Two kinds of eddy current probes are mainly used to perform the steam generator tube integrity assesment in NPPs. The first one is the bobbin probe using for inspection of volumetric defect like a fretting wear. The second one is the rotating probe using for inspection of non-volumetric defect like a crack. The eddy current probe is one of the essential components which consist of the whole eddy current examination system, and provides a decisive data for the tube integrity in accordance with acceptance criteria described in specific procedures. The design of ECT probe is especially important to improve examination results because the quality of acquired ECT data is depended on the probe design characteristics, such as coil geometry, electrical properties, operation frequency. In this study, it is analyzed that the coil winding number of differential bobbin probe affects the electrical properties of the probe. Eddy current bobbin probes for the steam generator tubes in NPPs are designed and fabricated according to the results. Experiment shows that the change in coil winding number has much effects on the optimum inspection frequency determined by the tube geometry and material. Therefore, the coil winding number in bobbin probe is very important in the probe design. In this study, a basis of the coil winding number for the eddy current bobbin probe design for steam generator tubes in NPPs is established.
A Principle of Radiographic Contrast
Joo, Gwang-Tae ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 71~77
DOI : 10.7779/JKSNT.2012.32.1.071
Recent Nondestructive Testing Using Structural Health Monitoring Techniques
Kim, Dae-Hyun ;
Journal of the Korean Society for Nondestructive Testing, volume 32, issue 1, 2012, Pages 78~85
DOI : 10.7779/JKSNT.2012.32.1.078