Evaluation of Closed Stress Corrosion Cracks in Ni-Based Alloy Weld Metal Using Subharmonic Phased Array

Horinouchi, Satoshi; Ikeuchi, Masako; Shintaku, Yuichi; Ohara, Yoshikazu; Yamanaka, Kazushi

doi:10.7567/jjap.51.07gb15

Cited by 14 publications

(19 citation statements)

References 24 publications

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“…There have been only a limited number of studies on the influence of oxide film formation in cracks on crack detectability and measures to cope with this influence [7]. considered unnecessary because what we investigate are relatively simple events or phenomena related to flaw detection in the object to be inspected, but not complex events or phenomena that occur in plant systems.…”

Section: Step 7 (Define High-level Basic Systemmentioning

confidence: 99%

Study of a methodology of identifying important research problems by the PIRT process

Aoki

Takagi

Kōmura³

et al. 2014

Journal of Nuclear Science and Technology

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In this paper, we propose a new methodology of identifying important research problems to be solved to improve the performance of some specific scientific technologies by the phenomena identification and ranking table (PIRT) process which has been used as a methodology for demonstrating the validity of the best estimate simulation codes in US Nuclear Regulatory Commission (USNRC) licensing of nuclear power plants. The new methodology makes it possible to identify important factors affecting the performance of the technologies from the viewpoint of the figure of merit and problems associated with them while it keeps the fundamental concepts of the original PIRT process. Also in this paper, we demonstrate the effectiveness of the new methodology by applying it to a task of extracting research problems for improving an inspection accuracy of ultrasonic testing or eddy current testing in the inspection of objects having cracks due to fatigue or stress corrosion cracking.

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Section: Step 7 (Define High-level Basic Systemmentioning

confidence: 99%

Study of a methodology of identifying important research problems by the PIRT process

Aoki

Takagi

Kōmura³

et al. 2014

Journal of Nuclear Science and Technology

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“…Since crack depth is a critical parameter for the maintenance management of aging infrastructures, the accurate measurement of crack depth has been intensively studied. [6][7][8][9][10][11][12][13][14][15][16][17] On the other hand, fracture mechanics 18) indicates that crack depth can change in the crack-length direction. 19,20) However, B-scan images obtained by a linear array transducer give a spatially-averaged crack geometry over the elevation aperture of the linear array transducer.…”

Section: Introductionmentioning

confidence: 99%

High-resolution 3D phased-array imaging of fatigue cracks using piezoelectric and laser ultrasonic system (PLUS)

Ohara

Remillieux

Ulrich

et al. 2022

Jpn. J. Appl. Phys.

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This paper reports the effectiveness of a novel imaging system, piezoelectric and laser ultrasonic system (PLUS), for the three-dimensional (3D) imaging of fatigue cracks with a high-resolution. The PLUS combines a piezoelectric transmitter and the two-dimensional (2D) mechanical scanning of a laser Doppler vibrometer, enabling the 2D matrix array with an ultra-multiple number of receiving points for 3D phased array imaging. After describing the principle and 3D imaging algorithm of PLUS, we show the fundamental 3D imaging capability of the PLUS in a flat-bottom-hole specimen with varying the number of receiving points under a fixed large receiving aperture. We then demonstrate that the PLUS with 4275 receiving points (i.e. 75 × 57) achieves high-resolution 3D imaging of a fatigue crack with a high signal-to-noise ratio, providing the outline of the fatigue crack geometry. We also discuss the effectiveness of the ultra-multiple receiving points for suppressing grating lobes and random noise.

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“…On the other hand, we previously proposed a method of combining a single-element piezoelectric transducer and a linear array transducer to image closed cracks 7 , 8 , 16 , 34 , 35 . Here, a piezoelectric transmitter was used to provide the large-amplitude incidence required for nonlinear ultrasonics 36 .…”

Section: Introductionmentioning

confidence: 99%

Exploring 3D elastic-wave scattering at interfaces using high-resolution phased-array system

Ohara

Remillieux

Ulrich

et al. 2022

Sci Rep

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The elastic-wave scattering at interfaces, such as cracks, is essential for nondestructive inspections, and hence, understanding the phenomenon is crucial. However, the elastic-wave scattering at cracks is very complex in three dimensions since microscopic asperities of crack faces can be multiple scattering sources. We propose a method for exploring 3D elastic-wave scattering based on our previously developed high-resolution 3D phased-array system, the piezoelectric and laser ultrasonic system (PLUS). We describe the principle of PLUS, which combines a piezoelectric transmitter and a 2D mechanical scan of a laser Doppler vibrometer, enabling us to resolve a crack into a collection of scattring sources. Subsequently, we show how the 3D elastic-wave scattering in the vicinity of each response can be extracted. Here, we experimentally applied PLUS to a fatigue-crack specimen. We found that diverse 3D elastic-wave scattering occurred in a manner depending on the responses within the fatigue crack. This is significant because access to such information will be useful for optimizing inspection conditions, designing ultrasonic measurement systems, and characterizing cracks. More importantly, the described methodology is very general and can be applied to not only metals but also other materials such as composites, concrete, and rocks, leading to progress in many fields.

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Evaluation of Closed Stress Corrosion Cracks in Ni-Based Alloy Weld Metal Using Subharmonic Phased Array

Cited by 14 publications

References 24 publications

Study of a methodology of identifying important research problems by the PIRT process

Study of a methodology of identifying important research problems by the PIRT process

High-resolution 3D phased-array imaging of fatigue cracks using piezoelectric and laser ultrasonic system (PLUS)

Exploring 3D elastic-wave scattering at interfaces using high-resolution phased-array system

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