Tunable bandgaps and defect states in 3D phononic hollow structures

Abstract

The tunable bandgaps of three-dimensional phononic structures with hollow spheres and rods were numerically examined. The Yablonovite Structure with the addition of spheres in Face Center Cubic arrangement was examined first. In addition, three-dimensional structures that have Simple Cubic and Base Centered Cubic symmetries have been examined with similar tunability behavior as the Yablonovite Structure. The calculations were performed by using the Finite Difference Time Domain method. The effect in the tunability of the bandgaps from different materials of the structure or fluids penetrating the structure and the effect of the geometrical parameters of the structures were also examined. The results showed that tunable phononic bandgaps could be achieved depending on the properties of the fluid that penetrates the hollow part of the structure. The performance of the Yablonovite Structure with spheres when placing defects was the last part of this research. The results of this work indicate that the practical design of tunable acoustic devices such as waveguides, sensors, and filters can be made through changing the properties of the constitutive materials and via fluid–solid interaction.