Finite element simulation of laser-generated surface acoustic wave for identification of subsurface defects

The characteristics of laser-generated ultrasonic wave with subsurface defects are investigated by finite element method (FEM). We used this method to model a subsurface hollow with a rectangular shape, which was used to represent a subsurface defect. The diffracted bulk modes and oscillation modes...

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Bibliographic Details
Published in:Optik (Stuttgart) 2020-04, Vol.207, p.163812, Article 163812
Main Authors: Zeng, Wei, Yao, Yeiyan, Qi, Shikai, Liu, Li
Format: Article
Language:English
Subjects:
Laser
Oscillating waves
Rayleigh waves
Subsurface defects
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Summary:The characteristics of laser-generated ultrasonic wave with subsurface defects are investigated by finite element method (FEM). We used this method to model a subsurface hollow with a rectangular shape, which was used to represent a subsurface defect. The diffracted bulk modes and oscillation modes result from the interaction between R-waves (Rayleigh waves) and subsurface defects are analyzed in detail. The amplitude of RE-waves (Echo waves) and O-waves (oscillating waves) results from subsurface defects change when the depth of subsurface defects increases. The sources and mechanism of E-waves and O-waves were studied. The maximum amplitude of 1–2 MHz, 2–3 MHz and 3–4 MHz changed very obvious and performed oscillation characteristics, we can select the maximum amplitude of laser-generated ultrasonic wave at different frequency can be used to detect the size and location of subsurface defect. The proposed method may provide a useful way to detect other types of subsurface structures.
ISSN:0030-4026
1618-1336
DOI:10.1016/j.ijleo.2019.163812