Ultrawide attenuation bands in gradient metabeams with acoustic black hole pillars

In this letter, it is suggested to attach acoustic black holes (ABHs) on a base beam with gradient parameters for wave attenuation in ultrawide bands. Three types of metabeams have been designed and compared. Analysis of the complex dispersion curves obtained by the wave and Rayleigh–Ritz method indicates that modifying the pillar length may cause some failure bands, which can be circumvented by changing the lattice constant. The forced vibrations of finite beams are recovered using the nullspace method, which has confirmed the merits of the metabeam with gradient lattice constant. This paper enriched the application range of ABHs.