• Title/Summary/Keyword: 위상잠금 적외선열화상

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Evaluation of Improvement of Detection Capability of Infrared Thermography Tests for Wall-Thinning Defects in Piping Components by Applying Lock-in Mode (적외선열화상 시험에서 위상잠금모드 적용에 따른 배관 감육결함 검출능력 개선 평가)

  • Kim, Jin Weon;Yun, Kyung Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.9
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    • pp.1175-1182
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    • 2013
  • The lock-in mode infrared thermography (IRT) technique has been developed to improve the detection capability of defects in materials with high thermal conductivity, and it has been shown to provide better detection capability than conventional active IRT. Therefore, to investigate the application of this technique to nuclear piping components, lock-in mode IRT tests were conducted on pipe specimens containing simulated wall-thinning defects. Phase images of the wall-thinning defects were obtained from the tests, and they were compared with thermal images obtained from conventional active IRT tests. It showed that the ability to size the detected wall-thinning defects in piping components was improved by using lock-in mode IRT. The improvement was especially apparent when detecting short and narrow defects and defects with slanted edges. However, the detection capability for shallow wall-thinning defects did not improve much when using lock-in mode IRT.

A Study about Detection of Defects in the Nuclear Piping Loop System Using Cooling Lock-in Infrared Thermography (원전 배관 루프시스템의 냉각 위상잠금 적외선열화상을 이용한 결함 검출에 관한 연구)

  • Kim, Sang-Chae;Kang, Sung-Hoon;Yun, Na-Yeon;Jung, Hyun-Chul;Kim, Kyeong-Suk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.35 no.5
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    • pp.321-331
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    • 2015
  • A study on the application of cooling defect detection was performed on the basis of a preceding study on the heated defect detection in nuclear piping loop system, using lock-in infrared thermography. A loop system with piping defects was made by varying the wall-thinning length, the circumference orientation angle, and the wall-thinning depth. The test was performed using an IR camera and a cooling device. Distance between the cooling device and the target loop system was fixed at 2 m. For analyzing experimental results, the temperature distribution data for cooling, and phase data were obtained. Through the analysis of this data, the defect length was measured. The reliability of the measurements for cooling defect conditions was shown to be higher in the lock-in infrared thermography data than the infrared thermography data.

Defects Evaluation at Lap Joint Friction Stir Welding by Lock-in Ultrasound Infrared Thermography (위상잠금 초음파 적외선열화상에 의한 겹치기 마찰교반용접부의 결함 평가)

  • Choi, Man-Yong;Park, Hee-Sang;Park, Jeong-Hak;Kang, Ki-Soo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.2
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    • pp.104-109
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    • 2010
  • Lap joint friction stir welding(LFSW) is an relatively new solid state joining process. A6061-T6 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio and good corrosion resistance. Test methods used in this paper, lock-in thermography, a phase difference between the defect area and the healthy area indicates the qualitative location and size of the defect. In this paper, the defects detected from the thermal image of mechanical properties for weld were evaluated and compared by the lock-in infrared thermography technique.

Shearing Phase Lock-in Infrared Thermography for Defects Evaluation of Metallic Materials Specimen (금속재료 시편의 결함평가에 대한 전단위상 Lock-in 적외선열화상 연구)

  • Park, Jeong-Hak;Choi, Man-Yong;Kim, Won-Tae
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.2
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    • pp.91-97
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    • 2010
  • This paper proposes method to evaluate the location and size of the internal defects of metallic specimens by the shearing phase lock-in infrared thermography. Until now, infrared thermography test for metal specimen of STS304 and Cu-Zn were conducted to find the best test conditions. However, In unspecified situation of the form and existence of defects, there was a disadvantage to takes a long time for finding the optimal experimental conditions. The defect detection and evaluation was performed at 60 MHz signal using lock-in and shearing-phase method under limited heating conditions. By shearing-phase distribution method, Defects for the maximum, minimum and zero points were quantitatively detected at the size and location of the subsurface. As results, application of the proposed technique was verified for STS304 and Cu7-Zn3 with artificial defect and factors affected defect evaluation were searched and analyzed.

NDE of the Internal Hole Defect of Dental Composite Restoration Using Infrared Lock-In Thermography (위상잠금 열화상기법을 이용한 치과용 복합레진 수복재의 내부 홀 결함에 대한 비파괴평가)

  • Gu, Ja-Uk;Choi, Nak-Sam
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.1
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    • pp.40-45
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    • 2013
  • The purpose of this study was to detect the pin hole defect of dental composite restoration using lock-in thermography method. Amplitude and phase images of the composite resin specimens were analyzed according to the lock-in frequency and the diameter of defect area. Through the amplitude image analysis, at lock-in frequency of 0.05 Hz, defect diameters 2-5 mm exhibited the highest amplitude contrast value between defective area and sound area. The lock-in frequency range of 0.3-0.5 Hz provided good phase angle contrast for the defect area. At lock-in frequency range of 0.5 Hz, defect diameter of 5 mm exhibited the highest phase contrast value. It is concluded that the infrared lock-in thermography method verified the effectiveness for detecting the pin hole defect of dental composite restoration.

A Study on the Health Evaluation in Spot Welded Zone by Using Optical Pulse and Lock-in Phase Infrared Thermography (광원 펄스와 위상잠금 적외선 열화상을 이용한 점용접부의 건전성 평가 연구)

  • Park, Hee Sang;Choi, Mang Yong;Kwon, Koo Ahn;Park, Jeong Hak;Kim, Won Tae;Lee, Bo Young
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.4
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    • pp.349-354
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    • 2013
  • The non-destructive testing using infrared thermography is extended to a variety of industries and non-destructive testing of welds using infrared thermography is also in progress in various ways. Currently, a non-destructive testing of electrical resistance spot welds which is mainly used is Radiography Testing. This study detected area of spot welds nugget using optical-infrared thermography. In the results, it is possible for detecting defects of nugget in a short period of time using pulse-infrared thermography.

Quantitative Defects Detection in Wind Turbine Blade Using Optical Infrared Thermography (광 적외선열화상을 이용한 풍력 블레이드의 결함 크기 정량화 연구)

  • Kwon, Koo-Ahn;Choi, Man-Yong;Park, Hee-Sang;Park, Jeong-Hak;Huh, Yong-Hak;Choi, Won Jae
    • Journal of the Korean Society for Nondestructive Testing
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    • v.35 no.1
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    • pp.25-30
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    • 2015
  • A wind turbine blade is an important component in wind-power generation, and is generally exposed to harsh environmental conditions. Ultrasonic inspection is mainly used to inspect such blades, but it has been difficult to quantify defect sizes in complicated composite structures. Recently, active infrared thermography has been widely studied for inspecting composite structures, in which thermal energy is applied to an object, and an infrared camera detects the energy emitted from it. In this paper, a calibration method for active optical lock-in thermography is proposed to quantify the size. Inclusion, debonding and wrinkle defects, created in a wind blade for 100 kW wind power generation, were all successfully detected using this method. In particular, a ${\phi}50.0mm$ debonding defect was sized with 98.0% accuracy.

Measurement Uncertainty on Subsurface Defects Detection Using Active Infrared Thermographic Technique (능동 적외선열화상 기법을 이용한 이면결함 검출에서의 측정 불확도)

  • Chung, Yoonjae;Kim, Wontae;Choi, Wonjae
    • Journal of the Korean Society for Nondestructive Testing
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    • v.35 no.5
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    • pp.341-348
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    • 2015
  • Active infrared thermography methods have been known to possess good fault detection capabilities for the detection of defects in materials compared to the conventional passive thermal infrared imaging techniques. However, the reliability of the technique has been under scrutiny. This paper proposes the lock-in thermography technique for the detection and estimation of artificial subsurface defect size and depth with uncertainty measurement.

Defect Detection of Impacted Composite Tubes by Lock-in Photo-Infrared Thermography Technique (위상잠금 열화상기법을 이용한 복합재 튜브 충격 손상 결함 측정)

  • Kim, Kyoung-Suk;Jeon, So-Young;Jung, Hyun-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.2
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    • pp.139-143
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    • 2011
  • 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.

Stress Analysis and Fatigue limit Evaluation of Plate with Notch by Lock-In Thermography (Lock-In Thermography를 이용한 노치시험편의 응력해석 및 피로한계치 평가)

  • Kim, Won-Tae;Kang, Ki-Soo;Choi, Man-Yong;Park, Jeong-Hak;Huh, Yong-Hak
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.5
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    • pp.315-320
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    • 2006
  • This paper describes stress analysis and fatigue limit evaluation of plate with V-notch and hole-notch by lock-in infrared thermography. Temperature variation of a specimen under cyclic loading is negatively proportional to the sum of principle stress change and the surface temperature measured by infrared camera is calculated to the stress of notch specimens, based on thermoelastic equation. And also, fatigue limitation can be evaluated by the change of intrinsic energy dissipation. Fatigue limitation of two notch specimens is evaluated as 164 MPa and 185 MPa, respectively and the stress measured by Lock-in infrared Thermography show good agreement within 10% error.