Time-Of-Flight recorded Pulsed Ultrasonic Polar Scan for elasticity characterization of composites

Abstract

In its orginal configuration, the pulsed ultasonic polarscan (P-UPS) mainly focussed on elastic material characterization through the inversion of amplitude landscape measurements. However, for several materials, special attention is required as minima in the transmission amplitudes do not exactly coincide with critical angles calculated from the Christoffel equations. Consequently, other means to extract the information on elastic moduli from P-UPS measurements are being investigated. In the present paper, we report on the use of time-of-flight ultrasonic polarscan (TOF-UPS) simulations as a new means of material characterization. Previous TOF inversions, although successful, were based on bulk wave approximations, which are not longer valid for thin materials. Our first inversion results on numerical cases demonstrate the usefulness of the new developed technique and highlight the added value compared to the bulk wave approximation 1 INTRODUCTION

The Ultrasonic Polar Scan for Composite Characterization and Damage Assessment: Past, Present and Future

“…Apart from the obtained successes, we still encountered some drawbacks and difficulties with an inversion procedure that is based on amplitude data only. For this reason we are currently implementing a more robust inversion procedure that accounts for both the TOF and amplitude landscape of a P-UPS recording (further details in Section 4.1) [21,22].…”

“…In order to reach this goal, we consider a two-step inversion approach [21,22]. The schematic roadmap of this approach is presented in Figure 15.…”

“…As such, we believe that our current effort may lead to a comprehensive approach in obtaining viscoelastic parameters for a wide range of (orthotropic) materials. As a matter of fact, we already successfully tested this system identification procedure for synthetic data [21,22], and we are now in the stage of applying this procedure to real experimental data.…”