Abstract
A numerical simulation study on elastic wave propagation of a phononic composite structure consisting of epoxy and tungsten carbide is presented for low-frequency elastic wave attenuation applications. The calculated dispersion curves of the epoxy/tungsten carbide composite show that the propagation of elastic waves is prohibited inside the periodic structure over a frequency range. To achieve a wide bandgap, the elastic composite structure can be optimized by changing its dimensions and arrangement, including size, number, and rotation angle of square inclusions. The simulation results show that increasing the number of inclusions and the filling fraction of the unit cell significantly broaden the phononic bandgap compared to other geometric tunings. Additionally, a nonmonotonic relationship between the bandwidth and filling fraction of the composite was found, and this relationship results from spacing among inclusions and inclusion sizes causing different effects on Bragg scatterings and localized resonances of elastic waves. Moreover, the calculated transmission spectra of the epoxy/tungsten carbide composite structure verify its low-frequency bandgap behavior.
Highlights
Elastic metamaterials are architecturally engineered structures that exhibit unusual properties to control the propagation of elastic waves through their structures [1,2]
The unit cell composed of a single-square inclusion within a soft host was studied by varying its filling fraction (FF)
The band gap generation in phononic crystals, consisting of square inclusions in the soft host, with various sizes, filling fractions, material parameters, and arrangements was investigated in this work; in general, it can be concluded that a wide bandgap of the phononic crystal can be formed by combining two mechanisms: high-frequency Bragg scattering and low-frequency local resonances
Summary
Elastic metamaterials are architecturally engineered structures that exhibit unusual properties to control the propagation of elastic waves through their structures [1,2]. By tuning the geometry, size, arrangement, and shape of the scatterers within the soft host, it could be possible to achieve band gaps with a wider frequency range by combining these two mechanisms [4]. This is useful for a variety of applications such as noise and vibration isolation [5,6,7,8,9], energy harvesting [10,11,12,13], and acoustic and elastic filters and waveguides [14,15,16,17]
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