(Color online) (a),(b) Schematic view of both the scatterer and the SC configurations of the device presented. (a) The transversal view of the 1 m long scatterer considered. The inner radius is m, the exterior radius is m, the aperture m, the rigid wall thickness m and the absorbent covering thickness m. (b) The size of the designed device is . The scatterers are arranged in a square array with lattice constant m. For this square periodicity the main directions of symmetry of the SC are () and ().
(Color online) Theoretical propagation properties of a SC made of rigid or absorbent scatters obtained with the three methods used in this work. (a) Bands structure (or dispersion relation) of a SC made of rigid scatterers with m and m. Black lines represent the analytical predictions calculated using PWE. Red dots show the numerical predictions calculated using FEM. Horizontal dashed lines represent a pseudogap. (b) and (c): corresponding scattering problem calculated for a SC of size made of rigid or absorbent scatterers, respectively. The SC is placed at 0.4 m from the source and centered with respect to the source-receiver line. The site of the receiver is m. Blue continuous line (blue dots) represents the attenuation spectrum for the direction predicted by MST (FEM). Red dashed line (red open circles) represents the attenuation spectrum for the direction predicted by MST (FEM).
(Color online) Experimental setup. (a) Picture of the single designed scatterer. (b) Scheme of the anechoic chamber, and pictures of both the experimental device designed and the robotized system 3DReAMS.
(Color online) Acoustic properties of both a single and a periodic array of RSRR. (a) Numerical (blue continuous line) and experimental (blue open circles) IL produced by an isolated RSRR. (c) Dispersion relation of a square periodic array with m made of RSRR. Strong gray area represents the attenuation band due to the resonance and weak gray area represents the pseudogap at direction. (b) and (d) are the numerical and experimental IL of a SC made of RSRR, respectively. Blue continuous and red dashed lines in (b) [open blue circles and open red squares in (d)] are the IL in the and directions, respectively.
(Color online) Study of the acoustical properties of a ASRR SC. (b) Dispersion relation of an square periodic array with m made of SRR with both m (black dashed lines) and m (red continuous line). Strong gray area represents the attenuation band due to the resonance, and weak gray area represents the pseudogap at direction. (a) and (c) represent the numerical and experimental IL of a SC made of ASRR, respectively. Blue continuous and red dashed lines in (a) [open blue circles and open red squares in (c)] represent the IL at and directions, respectively. In all cases, the dot-dashed black line represents the attenuation level predicted using Maekawa’s model for a classical barrier.
(Color online) (a) Picture of a conventional acoustic barrier. (b) Simulated acoustic barrier based on SC.
Directions of incidence, ranges of , and ranges of phase changes and , for each of the segments required to traverse the boundary of the irreducible first Brillouin zone for square lattice.
Article metrics loading...
Full text loading...