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Measurements of Grain Size Using Unf...

Vo, Nhi Nguyen Tuyet,

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Measurements of Grain Size Using Unfocused Ultrasonic Beam /

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Measurements of Grain Size Using Unfocused Ultrasonic Beam // Nhi Nguyen Tuyet Vo.
作者:	Vo, Nhi Nguyen Tuyet,
面頁冊數:	1 electronic resource (87 pages)
附註:	Source: Masters Abstracts International, Volume: 86-02.
Contained By:	Masters Abstracts International86-02.
標題:	Mechanical engineering. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31485839
ISBN:	9798383699942

Measurements of Grain Size Using Unfocused Ultrasonic Beam /
Vo, Nhi Nguyen Tuyet,

Measurements of Grain Size Using Unfocused Ultrasonic Beam /Nhi Nguyen Tuyet Vo. - 1 electronic resource (87 pages)

Source: Masters Abstracts International, Volume: 86-02.

Nondestructive evaluation (NDE) of aerospace structural members is essential before these members enter into service. Ultrasound NDE is a widely used technique for ensuring that these components are free from defects and safe for intended use. Researchers have found that in highly stressed components such as Ti-64 engine disks, anomalous grain distributions are a cause of early fatigue initiation, and ultrasonic measurements can estimate the grain size distribution in these members based on the level of frequency-dependent attenuation measurements. Previous studies involved investigating the relationship between grain size distribution and frequency attenuation slope using experimental and numerical simulation approaches. The present work focuses on experimentally characterizing the ultrasonic attenuation in Ti-64 samples with various grain distributions and examining if the frequency attenuation slope indicates the actual grain size distribution. Nine Ti-64 samples were studied including three calibrated samples with known grain sizes and six samples with unknown samples with similar grain size distribution as the three calibrated samples to rank the grain size distribution based on measured frequency attenuation slope. Unfocused ultrasonic transducers with different central frequencies and diameters were used to launch a parallel beam at the center of these samples for the measurements. The first and second reflected signals from the back-wall were collected and quantitatively analyzed for variability and repeatability using signal average and standard deviation. The main reference paper used is Bhattacharjee's 2011, which current work built upon, and was used to validate the method to determine the frequency-dependent attenuation behaviors.

English

ISBN: 9798383699942Subjects--Topical Terms:

649730
Mechanical engineering.
Subjects--Index Terms:

Nondestructive evaluation

Measurements of Grain Size Using Unfocused Ultrasonic Beam /
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520 $a Nondestructive evaluation (NDE) of aerospace structural members is essential before these members enter into service. Ultrasound NDE is a widely used technique for ensuring that these components are free from defects and safe for intended use. Researchers have found that in highly stressed components such as Ti-64 engine disks, anomalous grain distributions are a cause of early fatigue initiation, and ultrasonic measurements can estimate the grain size distribution in these members based on the level of frequency-dependent attenuation measurements. Previous studies involved investigating the relationship between grain size distribution and frequency attenuation slope using experimental and numerical simulation approaches. The present work focuses on experimentally characterizing the ultrasonic attenuation in Ti-64 samples with various grain distributions and examining if the frequency attenuation slope indicates the actual grain size distribution. Nine Ti-64 samples were studied including three calibrated samples with known grain sizes and six samples with unknown samples with similar grain size distribution as the three calibrated samples to rank the grain size distribution based on measured frequency attenuation slope. Unfocused ultrasonic transducers with different central frequencies and diameters were used to launch a parallel beam at the center of these samples for the measurements. The first and second reflected signals from the back-wall were collected and quantitatively analyzed for variability and repeatability using signal average and standard deviation. The main reference paper used is Bhattacharjee's 2011, which current work built upon, and was used to validate the method to determine the frequency-dependent attenuation behaviors.
546 $a English
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650 4 $a Mechanical engineering. $3 649730
650 4 $a Agricultural engineering. $3 3168406
653 $a Nondestructive evaluation
653 $a Grain size distribution
653 $a Ultrasonic beam
653 $a Fast Fourier Transform
690 $a 0548
690 $a 0539
710 2 $a North Carolina Agricultural and Technical State University. $b Mechanical Engineering. $e degree granting institution. $3 3830005
720 1 $a Sundaresan, Mannur J. $e degree supervisor.
773 0 $t Masters Abstracts International $g 86-02.
790 $a 1544
791 $a M.S.
792 $a 2024
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