• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.622-628
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• 2004

In general, Reinforced Slopes by Shotcrete are difficult to inspect because of stiff Slope and highly Working Area. So the Inspection Techniques are needed by the Non-contact and Non-destructive. On this Study, Appling the safety method to finding the weak zones(cavity area, dampness area, etc.) by using the Infrared Thermal Technique That is detecting the Detail Thermal Difference on the Surface of Reinforced Slopes by Shotcrete.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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• pp.60-66
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• 2016

This study used an ultrasound infrared thermography technique to detect issues in the motor core of typical power equipment. The current defect inspection method of the motor core is often incomplete (due to the limits of visual inspection) and thus the reliability of the motor core is reduced. Therefore, in this study, experiments were carried out to increase the reliability of the test by using an ultrasonic infrared thermal non-destructive inspection method to image the motor core. The ambient temperature of the experimental system was maintained at $25^{\circ}C$. Experiments were carried out to examine a damaged motor core and a defect-free motor core. Experimental results confirm the technique clearly detected defects in the motor core, thereby confirming the possibility of using this technique in the field.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.566-569
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• 2001

Hot Plate is the major unit that it used to remove damp of wafer surface, to strength adhesion of photoresist(PR) and to bake coated PR in FAB process of semiconductor. It is necessary to guarantee the performance of Hot Plate(HP). Therefore, in this study designed and developed the reliability system of HP to measure and estimated thermal uniformity and flatness in temperature setting amplitude $0~250^{\circ}C$. We developed the techniques that measures and analyzes thermal uniformity using infrared thermal vision, and compensates measuring error of flatness using laser displacement sensor. For measuring flatness, we specially makes the measurement stage of 3 axes which adopts the precision encoder. The allowable error of measuring technique is less than thermal uniformity, $\pm 0.1^{\circ}C$ and flatness, $\pm 1mm$. It is expected that the developed system can measure from $\Phi$210(wafer 8") to $\Phi$356(wafer 12") and also can be used in performance test of the Cool Plate and industrial heater, etc.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.83-91
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• 2005

This paper describes the structural strength test technique and the results for cylindrical supersonic vehicle subjected to both aerodynamic load and thermal load. The special positioning system using spring links was designed to float, support and restrain the test airframe during the test and the down-time. The hydraulic system and the electric heating system were utilized to apply the aerodynamic load and the thermal load to the test airframe together. Particularly, several hundreds of infrared quartz lamps were used for the heating system, and the thermal test conditions were successfully simulated. The test results showed that this kind of high temperature test is adequate to verify the structure integrity and produce useful engineering data which is necessary for the possible structural modification under thermal environments.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.3
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• pp.284-290
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• 2012

Infrared thermography uses infrared energy radiated from any objects above absolute zero temperature, and the range of its application has been constantly broadened. As one of the active test techniques detecting radiant energy generated when energy is applied to an object, ultrasound infrared thermography is a method of detecting defects through hot spots occurring at a defect area when 15~100 kHz of ultrasound is excited to an object. This technique is effective in detecting a wide range affected by ultrasound and vibration in real time. Especially, it is really effective when a defect area is minute. Therefore, this study conducted thermography through lock-in signal processing when an actual defect exists inside the austenite STS304 seamless pipe, which simulates thermal fatigue cracks in a nuclear power plant pipe. With ultrasound excited, this study could detect defects on the rear of a pipe by using an aluminium reflector. Besides, by regulating the angle of the aluminium reflector, this study could detect both front and rear defects as a single infrared thermography image.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.3
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• pp.193-199
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• 2015

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.

• Coupled systems mechanics
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• v.12 no.5
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• pp.445-459
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• 2023

In this study, a cyclic tensile test on a notched butterfly specimen made of woven glass fiber composite was performed on a modified Arcan fixture. During the mechanical test, the sample was monitored with a hybrid stereoscopic system comprised of two visible lights and one infrared camera. The visible light cameras were employed for kinematic measurements using a finite-element-based multiview correlation technique. A semi-hybrid correlation approach was followed, providing Lagrangian temperature fields of the Region of Interest. Due to the complex composite architecture and specimen shape, localized shearing was observed during the tensile loading. Furthermore, asymmetrical damage developed around the notches as revealed by localized strains and thermal hot spots.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.376-380
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• 2006

Temperature distribution measured to estimate the condition of an electrical apparatus is an absolute reference for the apparatus conditions and the difference between the reference temperature and the current temperature. Because of passive thermography, without the external thermal stimulation, the difference in surface temperature between the region of interest and back ground shows that the results can apply only to the estimation or the monitoring for the condition of loose terminal and the overload pertaining to the rise in temperature. However, a thermal diffusion in the active thermography is differently generated by the structure and condition of the surface and subsurface. This paper presents a nondestructive test using this behavior and deals with the results by heat injection and cooling to the apparatus. The buried discontinuity of subsurface could be detected by these techniques.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.2
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• pp.106-114
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• 2017

This paper presents an automated subsurface micro void detection technique based on pulsed infrared thermography for inspecting epoxy molding compounds (EMC) used in electronic device packaging. Subsurface micro voids are first detected and visualized by extracting a lock-in amplitude image from raw thermal images. Binary imaging follows to achieve better visualization of subsurface micro voids. A median filter is then applied for removing sparse noise components. The performance of the proposed technique is tested using 36 EMC samples, which have subsurface (below $150{\mu}m{\sim}300{\mu}m$ from the inspection surface) micro voids ($150{\mu}m{\sim}300{\mu}m$ in diameter). The experimental results show that the subsurface micro voids can be successfully detected without causing any damage to the EMC samples, making it suitable for automated online inspection.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.6
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• pp.686-695
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• 2012

This paper proposes a noncontact thermography technique for fatigue crack evaluation under a cyclic tensile loading. The proposed technique identifies and localizes an invisible fatigue crack without scanning, thus making it possible to instantaneously evaluate an incipient fatigue crack. Based on a thermoelastic theory, a new fatigue crack evaluation algorithm is proposed for the fatigue crack-tip localization. The performance of the proposed algorithm is experimentally validated. To achieve this, the cyclic tensile loading is applied to a dog-bone shape aluminum specimen using a universal testing machine, and the corresponding thermal responses induced by thermoelastic effects are captured by an infrared camera. The test results confirm that the fatigue crack is well identified and localized by comparing with its microscopic images.