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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 35, Issue 6 - Dec 2015
Volume 35, Issue 5 - Oct 2015
Volume 35, Issue 4 - Aug 2015
Volume 35, Issue 3 - Jun 2015
Volume 35, Issue 2 - Apr 2015
Volume 35, Issue 1 - Feb 2015
Selecting the target year
Evaluation of Fatigue Damage for Wind Turbine Blades Using Acoustic Emission
Jee, Hyun-Sup ; Ju, No-Hoe ; So, Cheal Ho ; Lee, Jong-Kyu ;
Journal of the Korean Society for Nondestructive Testing, volume 35, issue 3, 2015, Pages 179~184
DOI : 10.7779/JKSNT.2015.35.3.179
In this study, the flap fatigue test of a 48 m long wind turbine blade was performed for 1 million cycles to evaluate the characteristics of acoustic emission signals generated from fatigue damage of the wind blades. As the number of hits and total energy continued to increase during the first 0.6 million cycles, blade damage was constant. The rise-time result showed that the major aspects of damage were initiation and propagation of matrix cracks. In addition, the signal analysis of each channel showed that the most seriously damaged sections were the joint between the skin and spar, 20 m from the connection, and the spot of actual damage was observable by visual inspection. It turned out that the event source location was related to the change in each channel`s total energy. It is expected that these findings will be useful for the optimal design of wind turbine blades.
Comparison of FEA with Condition Monitoring for Real-Time Damage Detection of Bearing Using Infrared Thermography Techniques
Kim, Hojong ; Kim, Wontae ;
Journal of the Korean Society for Nondestructive Testing, volume 35, issue 3, 2015, Pages 185~192
DOI : 10.7779/JKSNT.2015.35.3.185
Since real-time monitoring systems, such as early fault detection, have been very important, an infrared thermography technique was proposed as a new diagnosis method. This study focused on damage detection and temperature characteristic analysis of ball bearings using the non-destructive, infrared thermography method. In this paper, for the reliability assessment, infrared experimental data were compared with finite element analysis (FEA) results from ANSYS. In this investigation, the temperature characteristics of ball bearing were analyzed under various loading conditions. Finally, it was confirmed that the infrared thermography technique was useful for the real-time detection of damage to bearings.
Thermal Imaging for Detection of SM45C Subsurface Defects Using Active Infrared Thermography Techniques
Chung, Yoonjae ; Ranjit, Shrestha ; Kim, Wontae ;
Journal of the Korean Society for Nondestructive Testing, volume 35, issue 3, 2015, Pages 193~199
DOI : 10.7779/JKSNT.2015.35.3.193
Active thermography techniques have the capability of inspecting a broad range simultaneously. By evaluating the phase difference between the defected area and the healthy area, the technique indicates the qualitative location and size of the defect. Previously, the development of the defect detection method used a variety of materials and the test specimen was done. In this study, the proposed technique of lock-in is verified with artificial specimens that have different size and depth of subsurface defects. Finally, the defect detection capability was evaluated using comparisons of the phase image and the amplitude image according to the size and depth of defects.
Internal Defect Position Analysis of a Multi-Layer Chip Using Lock-in Infrared Microscopy
Kim, Seon-Jin ; Lee, Kye-Sung ; Hur, Hwan ; Lee, Haksun ; Bae, Hyun-Cheol ; Choi, Kwang-Seong ; Kim, Ghiseok ; Kim, Geon-Hee ;
Journal of the Korean Society for Nondestructive Testing, volume 35, issue 3, 2015, Pages 200~205
DOI : 10.7779/JKSNT.2015.35.3.200
An ultra-precise infrared microscope consisting of a high-resolution infrared objective lens and infrared sensors is utilized successfully to obtain location information on the plane and depth of local heat sources causing defects in a semiconductor device. In this study, multi-layer semiconductor chips are analyzed for the positional information of heat sources by using a lock-in infrared microscope. Optimal conditions such as focal position, integration time, current and lock-in frequency for measuring the accurate depth of the heat sources are studied by lock-in thermography. The location indicated by the results of the depth estimate, according to the change in distance between the infrared objective lens and the specimen is analyzed under these optimal conditions.
NDE of Low-Velocity Impact Damage in GFRP Using Infrared Thermography Techniques
Kim, Ghiseok ; Lee, Kye-Sung ; Hur, Hwan ; Kim, Sun-Jin ; Kim, Geon-Hee ;
Journal of the Korean Society for Nondestructive Testing, volume 35, issue 3, 2015, Pages 206~214
DOI : 10.7779/JKSNT.2015.35.3.206
In this study, low-velocity impact damage (LVID) in glass fiber reinforced plastic (GFRP) was investigated using pulse thermography (PT) and lock-in thermography (LIT) techniques. The main objective of this study was to evaluate the detection performance of each technique for LVID in GFRP. Unidirectional and cross-ply GFRPs were prepared with four energy levels using a drop weight impact machine and they were inspected from the impact side, which may be common in actual service conditions. When the impacted side was used for both inspection and thermal loading, results showed that the suggested techniques were able to identify the LVID which is barely visible to the naked eye. However, they also include limitations that depend on the GFRP thickness at the location of the delamination produced by the lowest impact energy of five joule.
The Study of Micro Crack Detection in Dissimilar Metal Weld Using a Variable Ultrasound Infrared Thermography
Park, Jeong-Hak ; Park, Hee-Sang ; Choi, Man-Yong ; Kwon, Koo-Ahn ;
Journal of the Korean Society for Nondestructive Testing, volume 35, issue 3, 2015, Pages 215~220
DOI : 10.7779/JKSNT.2015.35.3.215
As a nondestructive inspection technology currently in use, infrared thermography has gradually expanded its application range to industry. The method detects only defect areas by grafting ultrasound on a technique of detecting infrared energy emitted from all objects with absolute temperature of 0 K and converting this energy into thermography for inspection. Ultrasound infrared thermography has merits including the ability to inspect a wide area in a short time without contacting the target object. This study investigated the applicability of the technique for defect detection using variable ultrasound excitation inspection methods on samples of Terfenol-D, a magnetostrictive material with a tunable natural resonant frequency.