Material characterization by surface wave parameters extraction using 3D vibrometer and ellipsometry

Abstract

This work focuses on the monitoring of the 3D propagation of ultrasonic surface waves used in non-destructive testing and evaluation. The ellipticity of the movement related to the Rayleigh wave, specifically the H/V parameter, is studied analytically, numerically, and experimentally on an aluminum block. The study involves generating signals from the theoretical harmonic expression of particle displacement issued from Rayleigh wave, carrying out numerical simulations using a finite element method, and generating the Rayleigh wave using a shear contact transducer with a 1 MHz central frequency in the experimental study. The work also involves appropriate filtering of signals to extract components with specific polarization and suppress other modes with low polarization energy. The obtained results for aluminum show a good agreement between the analytical, numerical, and experimental studies of Rayleigh wave ellipticity. Moreover, these H/V ratios are consistent with the theoretical values described in the literature. As a proof of concept, this method is also applied to simulation data to study orthotropic materials (wood/bone), obtaining promising results.