A modified star-shaped phononic crystal for the vibration wave filtration in plates: design and experiment

In the present paper, an auxetic tape composed of modified star-shaped unit cells is used to filter the propagation of elastic waves in two-dimensional structures. The pattern of the designed bandgaps and their capability to mitigate wave propagation is experimentally and numerically studied. First, the architecture of the conventional star-shaped unit cell is introduced, and according to the Bloch's theorem the phononic bandgaps are calculated for the one unit cell. The unit cells' dimensions are designed to provide a wide phononic bandgap over the low-frequency range of 400-1700 Hz. The geometry of the conventional star unit cell is modified toward two modified stars to enhance low-frequency bandgaps. These unit cells are then used as a filter tool in a two-dimensional panel, and they are numerically simulated using the finite element method. Excitation is locally applied to the panel, and a layer of phononic crystal surrounds its location. It is shown that the lattice band is capable of trapping waves inside the bounded area and can remarkably suppress the propagation of waves. Numerical results and the bandgap formation obtained from Bloch's theorem are verified with the results measured from an experiment.

Automated summary

In this paper, an auxetic tape composed of modified star-shaped unit cells is used to filter the propagation of elastic waves in two-dimensional structures. The pattern of the designed bandgaps and their capability to mitigate wave propagation is experimentally and numerically studied. It is shown that the lattice band is capable of trapping waves inside the bounded area and can remarkably suppress the propagation of waves. Numerical results and the bandgap formation obtained from Bloch's theorem are verified with the results measured from an experiment.