Author
Takahide Sakagami
Other affiliations: Osaka University
Bio: Takahide Sakagami is an academic researcher from Kobe University. The author has contributed to research in topics: Thermography & Nondestructive testing. The author has an hindex of 15, co-authored 146 publications receiving 1054 citations. Previous affiliations of Takahide Sakagami include Osaka University.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, several experimental investigations of newly developed thermographic NDT techniques based on the transient temperature measurements are described and several experimental results of the pulse heating NDT and the lock-in NDT are shown.
180 citations
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TL;DR: In this paper, a new quantitative NDT technique for delamination defects in concrete structures was developed based on the phase delay measurement using a lock-in infrared thermography under the application of periodical heating.
66 citations
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TL;DR: In this paper, the current situation of nondestructive inspection techniques used for fatigue crack detection in steel bridges, and then presents remote NDE techniques using infrared thermography developed by the author for detecting fatigue crack and structural integrity assessments.
Abstract: Long-standing infrastructure is subject to structural deterioration. In this respect, steel bridges suffer fatigue cracks, which necessitate immediate inspection, structural integrity evaluation or repair. However, the inaccessibility of such structures makes inspection time consuming and labour intensive. Therefore, there is an urgent need for developing high-performance nondestructive evaluation (NDE) methods to assist in effective maintenance of such structures. Recently, use of infrared cameras in nondestructive testing has been attracting increasing interest, as they provide highly efficient remote and wide area measurements. This paper first reviews the current situation of nondestructive inspection techniques used for fatigue crack detection in steel bridges, and then presents remote NDE techniques using infrared thermography developed by the author for fatigue crack detection and structural integrity assessments. Furthermore, results of applying fatigue crack evaluation to a steel bridge using the newly developed NDE techniques are presented.
54 citations
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TL;DR: VibroIR may be an effective method for the diagnosis of root dentinal microcracks in roots by helping to detect microcrack by the friction heat generated from ultrasonic vibration.
30 citations
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19 Mar 1999TL;DR: In this paper, the singularity of the temperature field near crack tips under application of the periodically modulated electric current was measured using differential thermography based on lock-in data processing technique.
Abstract: A new thermographic NDT technique was proposed, in which singularity of the temperature field near crack tips under application of the periodically modulated electric current was measured using differential thermography based on lock-in data processing technique. Experimental investigation was made on the resolution and the applicability in the detection of through-thickness cracks embedded in steel plate samples. Modulated electric current was applied to the cracked sample by an induction coil. Differential thermal images synchronized to the reference current modulation signal were taken by the differential thermography. Significant singular temperature field was observed at the crack tips in the differential thermal images. The cracks were found to be sensitively detected by the proposed technique in good resolution compared with the singular method using a conventional thermographic temperature measurement.
29 citations
Cited by
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TL;DR: This review focuses on the advances of IRT as a non-contact and non-invasive condition monitoring tool for machineries, equipment and processes.
697 citations
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TL;DR: In this paper, a non-destructive mechanoluminescence (ML) from SrAl2O4:Eu was used to visualize the stress distribution in a single image, which can emit three magnitudes higher visible light than that of well-known ML substance of quartz.
Abstract: Visualization of stress distribution has been realized by a nondestructive mechanoluminescence (ML) from SrAl2O4:Eu, which can emit three magnitudes higher visible light than that of well-known ML substance of quartz. A simulation result confirms that such a ML image successfully reflects the stress distribution. A kinetic model for ML of SrAl2O4:Eu is proposed.
451 citations
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University of Groningen1, PSL Research University2, École centrale de Lyon3, Delft University of Technology4, University of Padua5, Imperial College London6, Luleå University of Technology7, IMT Institute for Advanced Studies Lucca8, Technical University of Denmark9, University of Southampton10, University of Cape Town11, École Polytechnique Fédérale de Lausanne12, Aarhus University13, King's College London14, Hamburg University of Technology15, Czech Technical University in Prague16, Instituto Politécnico Nacional17, Polish Academy of Sciences18, University of Turin19, University of Trento20, Queen Mary University of London21, Saarland University22
TL;DR: This review summarizes recent advances in the area of tribology based on the outcome of a Lorentz Center workshop surveying various physical, chemical and mechanical phenomena across scales, and proposes some research directions.
347 citations
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TL;DR: In this article, a review of widely used temperature measurement methods and how they can be applied to temperature monitoring during material removal is presented, using criteria critical in measuring material removal, and the results presented in guide-format for participants in this field of work.
345 citations
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TL;DR: This review provides an exhaustive summary of most recent active thermographic methods used for aerospace applications according to their physical principle and thermal excitation sources.
Abstract: Active infrared thermography is a fast and accurate non-destructive evaluation technique that is of particular relevance to the aerospace industry for the inspection of aircraft and helicopters’ primary and secondary structures, aero-engine parts, spacecraft components and its subsystems. This review provides an exhaustive summary of most recent active thermographic methods used for aerospace applications according to their physical principle and thermal excitation sources. Besides traditional optically stimulated thermography, which uses external optical radiation such as flashes, heaters and laser systems, novel hybrid thermographic techniques are also investigated. These include ultrasonic stimulated thermography, which uses ultrasonic waves and the local damage resonance effect to enhance the reliability and sensitivity to micro-cracks, eddy current stimulated thermography, which uses cost-effective eddy current excitation to generate induction heating, and microwave thermography, which uses electromagnetic radiation at the microwave frequency bands to provide rapid detection of cracks and delamination. All these techniques are here analysed and numerous examples are provided for different damage scenarios and aerospace components in order to identify the strength and limitations of each thermographic technique. Moreover, alternative strategies to current external thermal excitation sources, here named as material-based thermography methods, are examined in this paper. These novel thermographic techniques rely on thermoresistive internal heating and offer a fast, low power, accurate and reliable assessment of damage in aerospace composites.
301 citations