Bandgap tunability of surface acoustic waves in a two-dimensional magneto-electro-elastic phononic crystal

The propagation of surface acoustic waves in two types of tunable magneto-electro-elastic phononic crystal structures is investigated, for which Terfenol-D rods are vertically deposited on the piezoelectric substrate or embedded in the piezoelectric substrate. The bandgaps of the phononic crystal structures are analyzed by using the finite element method considering the nonlinear physical characteristics of Terfenol-D under a magnetic field and compressive pre-stress. Furthermore, through a detailed discussion of the calculated results, it is shown that the bandgaps of surface acoustic waves can be enlarged and new bandgaps will appear under an appropriate magnitude of magnetic field and compressive stress. Therefore, the present numerical model may provide relevant guidance for adjusting the bandgaps of surface acoustic waves in a two-dimensional magneto-electro-elastic phononic crystal.