PLANE HORIZONTAL TRANSVERSE WAVES IN ELASTIC PIEZOPOWDERS

Abstract

A procedure and results of computer simulation of plane horizontal transverse waves are described. Three materials — gallium arsenide, bismuth germanate, and lead zirconate–titanate ceramics — are selected as the piezoelectric phase. The second phase of the powder is always lead. To describe waves in the powder, the microstructural theory of two-phase mixtures is used. Therefore, the computer simulation was intended to study the influence of the lead content by volume on the wave velocities and the microstructural wave-propagation pattern — decomposition of a wave into two modes, simultaneous propagation of both modes in each phase of the powder, etc. First, sets of physical constants (elastic, piezoelectric, and dielectric) of mixture theory were evaluated for three types of powders (with the piezoelectric phase as one of the above-mentioned materials) with the volume piezoelectric-phase content varying from 0.01 to 0.5 with step 0.005. Further, dispersion curves for both modes and 3D-graphs of amplitudes as functions of the wave propagation time and distance were plotted for 300 compositions of powders (three types, each of 100 modifications). Of the phenomena described, we should first of all point out that all the phase velocities increase twice upon changing the content of the powder in the piezoelectric phase from a very small amount to the maximum possible