Time-frequency analysis of laser-generated ultrasonic wave in coating-substrate systems

XU Bai-qiang; SHEN Zhong-hua; NI Xiao-wu; GUAN Jian-fei; LU Jian

Laser induced ultrasonic waves in coating-substrate systems are broadband and dispersive,and multiple propagation modes overlap in time domain.By using time-frequency analysis based on the Wigner-Ville distribution,the characters of modes and energy distribution are obtained after analyzing laser ultrasound signals in the coating-substrate system,which are obtained by means of the finite element method.Furthermore,time-frequency method provides a direct measurement velocity dispersion by delay estimation,whose advantage is that it only needs a single measured signal.

1. Department of Applied Physics, Nanjing University of Science & Technology, Nanjing 210094, China;

2. Faculty of Science, Jiangsu University, Zhenjiang 212013, China

Received Date: 2004-05-08

Accepted Date: 2004-08-10

Available Online: 2004-11-25

Abstract: Laser induced ultrasonic waves in coating-substrate systems are broadband and dispersive,and multiple propagation modes overlap in time domain.By using time-frequency analysis based on the Wigner-Ville distribution,the characters of modes and energy distribution are obtained after analyzing laser ultrasound signals in the coating-substrate system,which are obtained by means of the finite element method.Furthermore,time-frequency method provides a direct measurement velocity dispersion by delay estimation,whose advantage is that it only needs a single measured signal.

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Reference (19)

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Time-frequency analysis of laser-generated ultrasonic wave in coating-substrate systems

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