Go to the main menu
Skip to content
Go to bottom
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
Editor in Chief :
Volume & Issues
Volume 31, Issue 6 - Dec 2011
Volume 31, Issue 5 - Oct 2011
Volume 31, Issue 4 - Aug 2011
Volume 31, Issue 3 - Jun 2011
Volume 31, Issue 2 - Apr 2011
Volume 31, Issue 1 - Feb 2011
Selecting the target year
Performance of Different Sensors for Monitoring of the Vibration Generated during Thermosonic Non-destructive Testing
Kang, Bu-Byoung ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 111~117
Vibration monitoring is required for reliable thermosonic testing to decide whether sufficient vibration is achieved in each test for the detection of cracks. From a practical point of view, a cheaper and convenient monitoring method is better for the application to real tests. Therefore, the performance of different sensors for vibration monitoring was investigated and compared in this study to find a convenient and acceptable measurement method for thermosonics. Velocity measured by a laser vibrometer and strain provide an equivalent HI when measured at the same position. The microphone can provide a cheaper vibration monitoring device than the laser and the heating index calculated by a microphone signal shows similar characteristics to that calculated from velocity measured by the laser vibrometer. The microphone frequency response shows that it underestimates high frequency components but it is applicable to practical tests because it gives a conservative value of HI.
A Study on the Characteristics of the Excited Vibration Signals in a Thermosonic Test
Kang, Bu-Byoung ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 118~126
The characteristics of the responses obtained in thermosonic tests are investigated in this study to improve the performance of a thermosonic test system. Thermosonic tests are conducted with an acoustic horn with high power capability to investigate the characteristics of the vibration produced in turbine blades with complex geometry. The influences of the excitation signal that is input to the horn and the coupling methods between a clamp and the acoustic horn on the characteristics of the vibration excited in a component are presented. As a result, an excitation method with a fast narrow band chirp test (sweep test) and a stud coupling is proposed as an excitation method for thermosonic testing. This method can be applied to different types of turbine blades and also to other components.
Development of LabVIEW Program for Lock-In Infrared Thermography
Min, Tae-Hoon ; Na, Hyung-Chul ; Kim, Noh-Yu ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 127~133
A LabVIEW program has been developed together with simple infrared thermography(IRT) system to control the lock-in conditions of the system efficiently. The IR imaging software was designed to operate both of infrared camera and halogen lamp by synchronizing them with periodic sine signal based on thyristor(SCR) circuits. LabVIEW software was programmed to provide users with screen-menu functions by which it can change the period and energy of heat source, operate the camera to acquire image, and monitor the state of the system on the computer screen. In experiment, lock-in IR image for a specimen with artificial hole defects was obtained by the developed IRT system and compared with optical image.
Infrared Thermographic Diagnosis Mechanism for Fault Detection of Ball Bearing under Dynamic Loading Conditions
Seo, Jin-Ju ; Yoon, Han-Vit ; Kim, Dong-Yeon ; Hong, Dong-Pyo ; Kim, Won-Tae ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 134~138
Fault detection for dynamic loading conditions of rotational machineries was considered from the contactless, non-destructive infrared thermographic method, rather than the traditional diagnosis method. In this paper, by applying a rotating deep-grooved ball bearing, passive thermographic experiment was performed as an alternative way proceeding the traditional fault monitoring. In addition, the thermographic experiments were compared with the vibration spectrum analysis to evaluate the efficiency of the proposed method. Based on the results, it was concluded the temperature characteristics of the ball bearing under dynamic loading conditions were analyzed thoroughly.
Defect Detection of Impacted Composite Tubes by Lock-in Photo-Infrared Thermography Technique
Kim, Kyoung-Suk ; Jeon, So-Young ; Jung, Hyun-Chul ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 139~143
The problem of delamination of composite tubes by impact has been acknowledged in aerospace and automobile industry. Non-destructive testing(NDT) methods in composite material structure are important to evaluate reliability of composite structure. There are many kinds of NDT methods which can detect the inside defect of the composite material such as Infrared Thermography(IRT). Infrared thermal imaging of object is different from that of a defect, in heated composite tubes with an internal defect, and then location and size of a defect can be measured by the analysis of thermal imaging pattern. In this study, Lock-in Infrared thermography detect internal defects of Impacted composite tubes by the inspection of infrared lay radiated from the surface of composite tubes.
Integrity Evaluation of Railway Bogie Using Infrared Thermography Technique
Kim, Jeong-Guk ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 144~149
The lock-in thermography was employed to evaluate the integrity of railway bogies. Prior to the actual application on railway bogies, in order to assess the detectability of known flaws, the calibration reference panel was prepared with various dimensions of artificial flaws. The panel was composed of structural steel, which was the same material with actual bogies. Through lock-in thermography evaluation, the optimal frequency of heat source was determined for the best flaw detection. Based on the defects information, the actual defect assessments on railway bogie were conducted with different types of railway bogies, which were used for the current operation. In summary, the defect assessment results with thermography method showed a good agreement as compared with the conventional inspection techniques. Moreover, it was found that the novel infrared thermography technique could be an effective way for the inspection and the detection of surface defects on bogies since the infrared thermography method provided rapid and non-contact mode for the investigation of railway bogies.
Study on the Qualitative Defects Detection in Composites by Optical Infrared Thermography
Park, Hee-Sang ; Choi, Man-Yong ; Park, Jeong-Hak ; Kim, Won-Tae ; Choi, Won-Jong ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 150~156
In this paper, infrared thermography measurement technique has been used to develop standard measurement technique for nondestructive testing of composite materials which is widely used in aerospace industries. To increase the defect detection rate, the related experiment used the lock-in IR-thermographiy method. Therefore it is of considerable interest in the field of non-destructive testing for fast discontinuity detection by using ultrasonic lock-in infrared thermography. The result also shows that as the investigation period of light source is lengthened according to the thickness of specimen, the possibility of detecting defects gets higher as well. However, the reason why the result values were not favorable when less than 50 mHz of light source was provided is because it was difficult to detect defects as the defect parts became a state of thermal equilibrium in general when thermal diffusivity affects the entire materials.
An Exploratory Study on the Optimized Test Conditions of the Lock-in Thermography Technique
Cho, Yong-Jin ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 157~164
This work is devoted to the technique application of lock-in infrared Thermography in the shipbuilding and ocean engineering industry. For this purpose, an exploratory study to find the optimized test conditions is carried out by the design of experiments. It has been confirmed to be useful method that the phase contrast images were quantified by a reference image and weighted by defect hole size. Illuminated optical intensity of lower or medium strength give a good result for getting a phase contrast image. In order to get a good phase contrast image, lock-in frequency factors should be high in proportion to the illuminated optical intensity. The integration time of infrared camera should have been inversely proportional to the optical intensity. The other hand, the difference of specimen materials gave a slightly biased results not being discriminative reasoning.
Real-Time Source Classification with an Waveform Parameter Filtering of Acoustic Emission Signals
Cho, Seung-Hyun ; Park, Jae-Ha ; Ahn, Bong-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 165~173
The acoustic emission(AE) technique is a well established method to carry out structural health monitoring(SHM) of large structures. However, the real-time monitoring of the crack growth in the roller coaster support structures is not easy since the vehicle operation produces very large noise as well as crack growth. In this investigation, we present the waveform parameter filtering method to classify acoustic sources in real-time. This method filtrates only the AE hits by the target acoustic source as passing hits in a specific parameter band. According to various acoustic sources, the waveform parameters were measured and analyzed to verify the present filtering method. Also, the AE system employing the waveform parameter filter was manufactured and applied to the roller coaster support structure in an actual amusement park.
Evaluation of Elastic Properties and Analysis of Contact Resonance Frequency of Cantilever for Ultrasonic AFM
Park, Tae-Sung ; Kwak, Dong-Ryul ; Park, Ik-Keun ; Kim, Chung-Seok ; Jhang, Kyung-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 174~180
Nondestructive surface imaging of elastic characteristic and mechanical property has been studied on nanoscale surface with ultrasonic AFM. Resonance frequency variation of cantilever is theoretically analyzed with respect to contact mechanics as well as experimentally measured. The contact resonance frequency is calculated theoretically using the spring-mass and Herzian model in accordance with the resonance frequency of UAFM cantilever measured experimentally. Consequently, the topography and amplitude images could be obtained successfully and the elastic characteristic at the nanoscale surface was evaluated qualitatively by amplitude signals.
Principles and System Configuration of Infrared Thermograpby
Kim, Won-Tae ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 181~188
Phase-Extraction Algorithm over a Lock-in Infrared Thermography
Kim, Noh-Yu ;
Journal of the Korean Society for Nondestructive Testing, volume 31, issue 2, 2011, Pages 189~192