Sonic stop-bands for periodic arrays of metallic rods: Honeycomb structure

Extensive band structures have been computed for periodic arrays (in the ho neycomb structure) of rigid metallic rods in air. Multiple complete acousti c stop bands have been obtained within which sound and vibrations are forbi dden. These gaps start opening up for a filling fraction f greater than or equal to 8% and tend to increase with the filling fraction, exhibiting a ma ximum at the close-packing. th tandem structure has also been proposed that allows an ultrawideband filter for environmental or industrial noise to be achieved in the desired frequency range. This work is motivated by the rec ent experimental observation of sound attenuation on the sculpture by Euseb io Sempere, exhibited at the Juan March Foundation in Madrid [21] and compl ements the corresponding theoretical work [22, 23]. (C) 1998 Academic Press .