Transient elastic wave propagation and scattering in plates: comparison between pulsed TV-holography measurements and finite element method predictions

Abstract

Pulsed TV-holography (PTVH) can be used for obtaining two-dimensional maps of instantaneous out-of-plane displacements in plates. In particular, our group has demonstrated that scattering patterns generated by the interaction of elastic waves with defects can be measured with PTVH and employed for quantitative characterization of damage in non-destructive inspection in plate structures. Recently, we have succeeded in obtaining a quantitative description of experimental scattering patterns produced by holes in harmonic regime using a finite element method (FEM) applied to a two-dimensional model based on the scalar wave equation, avoiding the standard and more complex vector approach based on the rigorous linear elasticity theory. In this work, a similar scheme is employed to characterize equivalent scattering phenomena but in transient regime. Simulated propagation and scattering patterns are tried with the scalar FEM and the corresponding experimental propagation and interaction of Rayleigh-Lamb waves with artificial defects in plates are measured using our specifically developed PTVH system. On this basis, a comparison between experimental maps and FEM simulated maps is developed.

Quantitative analysis of the agreement between scalar finite element simulation and pulsed TV-holography detection of the scattering of Rayleigh-Lamb waves in plates

“…can be extracted by analyzing the features of the associated scattering pattern. We have also shown that the direct problem of the scattering of Rayleigh-Lamb waves by through-thickness defects in plates can be solved by using numerical methods combined with a simplified 2-D scalar model, rendering numerical scattering patterns that by visual comparison show a reasonable agreement with the experiment, both in harmonic and transient regimes, except for the amplitude in the backscattering zone [6][7][8][9] .…”