The acoustic modality yields non destructive testing techniques of choice for indepth investigation. Given a precise model of acoustic wave propagation in materials of possibly complex structures, acoustical imaging amounts to the so-called acoustic wave inversion. A less ambitious approach consists in processing pulse-echo data (typically, Aor B-scans) to detect localised echoes with the maxim...

A plane-wave-expansion method suited to the analysis of surface-acoustic-wave propagation in two-dimensional piezoelectric phononic crystals is described. The surface modes of a square-lattice Y-cut lithium niobate phononic crystal with circular void inclusions with a filling fraction of 63% are identified. It is found that a large full band gap with a fractional bandwidth of 34% exists for sur...

The full set of electromechanical data of langasite (La3Ga5SiO14) is determined in the temperature range from 20 to 900 C using differently oriented bulk acoustic wave resonators. For data evaluation a physical model of vibration is developed and applied. Thereby, special emphasis is taken on mechanical and electrical losses at high temperatures. The resulting data set is used to calculate the ...

The numerical simulation of shallow water acoustic propagation has given rise to a wide variety of modeling techniques with various degrees of accuracy. One technique, involving finite difference methods, is more commonly used in the description of seismic propagation but also occurs in the shallow water propagation literature. This word reported here involves the application of finite differen...

A microelectromechanical system (MEMS) sound waveguide is considered as a transmission line for RF signals. We analyze a device geometry of a straight one-dimensional microsize silicon rod, where a longitudinal acoustic wave is generated and detected using capacitive transducers. Linear, isotropic, and nondispersive acoustic-wave propagation is assumed. Based on the calculation of the electrome...