Transmittivity through straight and stublike waveguides in a two-dimensional phononic crystal

Abstract

We study theoretically the propagation of acoustic waves through a linear waveguide, created inside a two-dimensional phononic crystal, along which a side branch ͑or stub͒ is attached. The primary effect of this resonator is to induce zeros of transmission in the transmission spectrum of the perfect waveguide. The transmittivity exhibits very narrow dips whose frequencies depend upon the width and the length of the stub. When a gap exists in the transmittivity of the perfect waveguide, the stub may also permit selective frequency transmission in this gap. We have considered phononic crystals constituted by either fluid or solid constituents. The calculations of the band structure and transmittivity are performed by a combination of finite-difference time domain and plane-wave expansion methods.

Directional bending wave propagation in periodically perforated plates

“…Among the configurations proposed, the use of plate structures as propagation media is an attractive solution due to the existence of several theories to support the formulation of numerical models, and the ease of experimentation provided by optical measurement systems such as scanning laser vibrometers and interferometers. For these reasons, a number of recent studies have investigated elastic plates with periodic inclusions and voids, microstructures, and sources of impedance mismatch such as surface mounted stubs [14,15,16] to generate phononic plates and elastoacoustic metamaterials [17,18]. In particular, the work of [12,8,6,7] focuses on flexural (transverse) waves in periodically perforated plates.…”

Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

“…This concept would represent an analogy to the macroscale PnC waveguide which is used to channel acoustic or elastic waves. 8,[50][51][52] Other similar adoptions may also be done in the broader context of the emerging field of phononics.…”

Development of an Acoustic Metamaterials for Aero Acoustic Noise Control

“…This capability offers constructing new meta materials with special performance for vibration control (Bergamini, 2014) or acoustic shield with applications in designing elastic filters, wave guides, mirrors, and transducers. Similarly, several phenomena such as guiding (Torres, 1999); (Kafesaki 2000); (Khelif, 2003), bending (Miyashita, 2002), (Khelif, 2004), filtering (Khelif, 2002); (Khelif, 2003), demultiplexing (Pennec, 2004), and super lenses of acoustic waves (Pennec, 2005) have been predicted, so far. In addition, phononic crystals can tailor the allowed modes and their wave speeds inside the material, in such a way that the frequencies of various material loss subjected to different regimes to be matched with the density of some states and frequencies of some modes provide enhanced energy absorption (Thomas et al, 2011).…”