Phononic band gap crystals with periodic fractal inclusions: Theoretical study using numerical analysis

Abstract

Elastic and viscoelastic effects in rubber/air acoustic band gap structures: A theoretical and experimental study J. Appl. Phys.A numerical study is conducted using finite difference time-domain analysis to determine the impact of periodic fractal-shaped inclusions on the frequency response of two-dimensional phononic or acoustic band gap crystals. Both solid host with solid inclusions and solid host with fluid inclusions were studied with increasing fractal order iteration or increasing fractal dimensionality for different types of fractals generated from square inclusions in a square lattice formation. Solid-fluid systems showed marked changes in frequency response including increasing multiplicity of bands compared to regular square inclusion shapes. Fractal inclusions in the solid host/fluid inclusion systems studied exhibited the ability to provide band gaps for much longer wavelengths than those of the solid host/solid inclusion systems studied. This behavior was attributed to the possibility of resonant localization effects that a fractal fluid inclusion can exhibit compared to fractal solid inclusions.

Harnessing structural hierarchy to design stiff and lightweight phononic crystals

“…Typical examples range from Eiffel tower to hierarchically architected nanotrusses with multiple length scales [10][11][12]. Recent studies show that it is possible to manipulate wave propagation by harnessing multiscale characteristic of hierarchical architectures [13][14][15]. These rationally designed hierarchical architectures can give rise to multiple and broadband phononic band gaps as well as low frequency band gaps.…”

Wave localization in randomly disordered layered three-component phononic crystals with thermal effects

“…In recent years, the elastic wave propagation in periodic composites (called phononic crystals) has been studied extensively [1][2][3][4][5][6][7][8][9][10][11][12][13]. With the band gap property, this kind of system has various potential applications such as the acoustic transducers and filters.…”

Observation of water surface wave localization in a trough with periodic sidewalls

“…Due to the existence of a periodic structure, there will be a lot of interesting phenomena during the wave propagation, such as negative refractive index, 2 slow light, 3 etc. It has great application prospects in photonic crystals, 4,5 phononic crystals, [6][7][8][9] and bio-inspired periodic composites. 10,11 When defects are introduced in a perfect periodic structure, the waves are always localized around the defect.…”