Signal processing in attenuation measurement with laser ultrasonics

Abstract

This research uses laser ultrasonics and signal processing to quantify the frequency-dependent attenuation losses of Rayleigh waves on viscoelastic materials. The high fidelity, large frequency bandwidth, steady output and noncontact nature of laser excitation makes this an ideal method to measure attenuation in these materials. Through the signal process of windows, filtering, FFT and coherent analysis to the Rayleigh signal, the relation between attenuation and frequency is obtained. The obtained results show that appropriate signal processing method is effective to the attenuation measurement with laser ultrasonics.