Controlling bandgap in electroactive polymer-based structures

A waveguide with a periodic structure is able to filter waves whose frequencies lie in the band-gap ranges  displayed in dispersion diagrams. The lengths of these forbidden bands depend on the contrast in material and geometrical properties of parts of the system which realize the periodicity. In this paper, a novel way to  control band gaps is proposed: to set the geometric characteristics of a prestretched waveguide made of soft dielectric elastomer applying an external voltage to pairs of electrodes applied with a regular pattern on the  device. The technique proves to be feasible and is able to tune accurately the position of band gaps over all frequency spectrum. For the investigated system, a device able to guide flexural waves, bandgap ranges of  about 100–200 Hz have been obtained over frequencies on the order of 1 kHz.