A BEM for band structure and elastic wave transmission analysis of 2D phononic crystals with different interface conditions

2018 ◽  
Vol 144 ◽  
pp. 110-117 ◽  
Author(s):  
Feng-Lian Li ◽  
Yue-Sheng Wang ◽  
Chuanzeng Zhang
2012 ◽  
Vol 100 (21) ◽  
pp. 213503 ◽  
Author(s):  
Joo Hwan Oh ◽  
Hoe Woong Kim ◽  
Pyung Sik Ma ◽  
Hong Min Seung ◽  
Yoon Young Kim

Author(s):  
Megan Hathcock ◽  
Bogdan-Ioan Popa ◽  
K. W. Wang

Abstract Recently the presence of a Dirac cone within the band structure of graphene has inspired research on phononic crystals with Dirac-like behaviors — including structures mimicking zero refractive index materials. The interesting phenomena produced by these structures occur at fixed frequencies and cannot be adaptive to needs and environmental changes. To address this constraint, researchers have designed tunable phononic structures; however, the tunable frequency ranges from the studies reported to date are limited by geometric constraints. Using a reconfigurable origami structure to modulate between different classes of phononic Bravais lattices, this research numerically investigates the effects of phononic lattice perturbation to produce drastic changes in the frequency of useful accidental degeneracies.


2014 ◽  
Vol 06 (01) ◽  
pp. 1450005 ◽  
Author(s):  
WEI LIU ◽  
YONGQUAN LIU ◽  
XIANYUE SU ◽  
ZHENG LI

In this paper, an interface/surface element is formulated based on the Gurtin–Murdoch interface/surface elasticity theory for accounting the interface/surface effect on the elastic wave propagation in two-dimensional nanosized phononic crystals. The interface/surface element is subsequently incorporated into the finite element procedure for calculating the elastic wave band structure of two-dimensional nanosized phononic crystals with consideration of the interface/surface effect. Elastic wave band structures of two-dimensional phononic crystals comprising a square array of circular or elliptical cylindrical nanoholes embedded in an aluminum matrix are analyzed. Numerical results evidence that the interface/surface effect on the elastic wave band structure can be remarkable when the characteristic size reduces to nanometers.


Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 66
Author(s):  
Connor D. Pierce ◽  
Kathryn H. Matlack

Phononic crystals (PCs) have been widely reported to exhibit band gaps, which for non-dissipative systems are well defined from the dispersion relation as a frequency range in which no propagating (i.e., non-decaying) wave modes exist. However, the notion of a band gap is less clear in dissipative systems, as all wave modes exhibit attenuation. Various measures have been proposed to quantify the “evanescence” of frequency ranges and/or wave propagation directions, but these measures are not based on measurable physical quantities. Furthermore, in finite systems created by truncating a PC, wave propagation is strongly attenuated but not completely forbidden, and a quantitative measure that predicts wave transmission in a finite PC from the infinite dispersion relation is elusive. In this paper, we propose an “evanescence indicator” for PCs with 1D periodicity that relates the decay component of the Bloch wavevector to the transmitted wave amplitude through a finite PC. When plotted over a frequency range of interest, this indicator reveals frequency regions of strongly attenuated wave propagation, which are dubbed “fuzzy band gaps” due to the smooth (rather than abrupt) transition between evanescent and propagating wave characteristics. The indicator is capable of identifying polarized fuzzy band gaps, including fuzzy band gaps which exists with respect to “hybrid” polarizations which consist of multiple simultaneous polarizations. We validate the indicator using simulations and experiments of wave transmission through highly viscoelastic and finite phononic crystals.


Author(s):  
Victor Gustavo Ramos Costa Dos Santos ◽  
Edson Jansen Pedrosa de Miranda Junior ◽  
Jose Maria Campos dos Santos

Sign in / Sign up

Export Citation Format

Share Document