Tunable fluid-filled phononic metastrip.

We study the propagation of Lamb waves in a one-dimensional tunable phononic metastrip composed of a periodic sequence of hollow pillars that can be selectively filled with water. Band structures and transmission properties are computed numerically for metastrips with different fluid fillings by using the finite element method. Good agreement is observed with experimental results obtained with an aluminum metastrip. In particular, it is found that the frequency range of bandgaps and passbands can be controlled through fluid filling. Our results imply that Lamb waves in the solid metastrip can be harnessed through changing the properties of the pillars via fluid-solid interaction. The work in this paper is relevant to practical design of tunable acoustic devices. [ABSTRACT FROM AUTHOR]