This paper presents the state-of-the-art of using non-destructive testing (NDT) methods based on elastic waves for the condition assessment of structural timber. Two very promising approaches based on the propagation and reflection of elastic waves are described. While the first approach uses ultrasonic echoes for the testing of wooden building elements, the second approach uses guided waves (G...

Multicomponent data are not usually processed with specifically designed procedures, but with procedures analogous to the ones used for single-component data. In isotropic media, the vertical and horizontal components of the data are commonly taken as proxies for the Pand S-wave modes which are imaged independently with acoustic wave equations. This procedure works only if the vertical and hori...

Classical acoustic and elastic wave scattering problems from an acoustically rigid or soft cylinder are revisited. The behavior of phases as well as magnitudes of each partial waves and form functions are numerically analyzed and discussed. The effect of mode conversion, especially, on the phases of each partial waves in elastic wave scattering is identified.

Multi-component data are not usually processed with specifically designed procedures, but with procedures analogous to the ones used for single-component data. Commonly, the vertical and horizontal components of the data are taken as proxies for P and S wave modes which are imaged independently with the acoustic wave equation. This procedure works only if the vertical and horizontal component a...

The combination of classical time reversal techniques and nonlinear elastic wave response, induced by the presence of a localized area of damage, brings about a significant enhancement of nonlinear imaging. In this paper, this concept is discussed from a numerical point of view, using multiscale Finite Difference Time Domain and PseudoSpectral Time Domain elastic wave solvers.

The classical theory of wave propagation in elastic cylinders is extended to poro-elastic mandrel modes. The classical theory predicts the existence of undamped L modes and damped C, I, and Z modes. These waves also appear in poro-elastic mandrels, but all of them become damped because of viscous effects. The presence of the Biot slow bulk wave in the poro-elastic material is responsible for th...