Quantitative characterization of laser ultrasonic based on energy loss and resonance phenomenon

Qin, Feng; Li, Bing; Chen, Lei; Tang, Tao; Wei, Xiang; Gao, Fei; Shang, Zhongyu

doi:10.1016/j.ijleo.2020.165380

Cited by 8 publications

(4 citation statements)

References 26 publications

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“…The wavelet basis dmey can be used to effectively analyze LU waves with non-stationary propagation characteristics. 19 Therefore, the wavelet function dmey is employed to perform five-layer WD for a low-pass filter. Moreover, the MATLAB infinite impulse response based on band-pass filtering is used to further improve the SNR.…”

Section: Resultsmentioning

confidence: 99%

“…The signal acquired by the experimental system is preprocessed to effectively improve the SNR, thus revealing the signal characteristics. The wavelet basis dmey can be used to effectively analyze LU waves with non‐stationary propagation characteristics 19 . Therefore, the wavelet function dmey is employed to perform five‐layer WD for a low‐pass filter.…”

Section: Resultsmentioning

confidence: 99%

“…The pulsed laser is focused vertically downward through the reflector and the focusing lens onto the surface of the sample, and the spot diameter is approximately 7 mm. Applying spectral analysis to the LU pulse, the central frequency and bandwidth of the surface acoustic wave probe are 2.5 and 5 MHz, respectively 19 . The laser spot is focused at 2 mm from one side of the defect, while the probe is placed 5 mm away from the other side of the defect.…”

Section: Methodsmentioning

confidence: 99%

“…Applying spectral analysis to the LU pulse, the central frequency and bandwidth of the surface acoustic wave probe are 2.5 and 5 MHz, respectively. 19 The laser spot is focused at 2 mm from one side of the defect, while the probe is placed 5 mm away from the other side of the defect. The LU transmission wave is used to extract and analyze defects in this experiment.…”

Section: Wavelet Packet Energymentioning

confidence: 99%

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Defect measurement using the laser ultrasonic technique based on power spectral density analysis and wavelet packet energy

Qiu

et al. 2021

Micro & Optical Tech Letters

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The laser ultrasonic technique (LUT) enables the analysis of complex signals and the extraction of the features of defects. The time-domain features can be used to quantify various defects, but are negatively affected by the coupling efficiency, measurement noise, and surface roughness during LUT. This paper describes defect analysis methods based on the power spectral density and wavelet packet energy. Defects are characterized using the power of low-frequency components after wavelet decomposition and the wavelet packet energy, and then linear relationships are established for two defect types. The R 2 values of the linear fitting for the characteristic variables of the defect are greater than 0.96. The experimental results show that the proposed methods provide effective and quantitative characterization of the defect size from laser ultrasonic signals.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Wavelet Packet Energymentioning

confidence: 99%

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