Phononic Crystals And Wave Mechanics Characteristics Of Structure Design

Phononic crystals are a kind of periodic structure composed of two kinds ormore elastic/fluid materials. Such artificial crystals can exhibit acoustic orelastic band gaps in which sound and vibration are all forbidden. This uniquefeature of Phononic crystals provides new prospects for engineering applicationsuch as sound insulation, noise control or the design of acoustic devices.Therefore, the topic has received a great deal of attention in recent years. In thispaper, the plane wave expansion （PWE） method is applied to calculate the bandstructures of the two-dimensional orthotropic phononic crystals with squarelattice, and the relations between the band structures or the width of band gapsand the parameters are investigated. Based on the plane wave expansion （PWE）method we carry out the studies in following aspects:This paper studies the two-dimensional anisotropic phononic crystal（AlAs/GaAs） the influence of material parameters. The results show that nocomplete band gaps but directional band gaps exhibit in the in-plane bandstructures when there is much difference of material parameters between thematrixes and scattered. And it is shown that theρ_a ρ_bhas a more significantlyaffect than theC_44a C_44b orC11a C11bon the in-plane band structures. Inaddition, there are complete band gaps appear in the out-plane band structures.The case exhibits theC_44a C_44b has a more apparent affect than theρ_a ρ_bonthe out-plane band structures.This paper studies the two-dimensional anisotropic phononic crystal（AlAs/GaAs） the influence of filling rate. For two-dimensional anisotropicphononic crystal, no matter when the filling rate changes cannot obtain completeband gap. In-plane mode filling rate impact on the frequency band gap larger.Out-of-plane modes filling rate on the low frequency direction gap influence.However, when the filling rate was f≤0.3, filling rate effects on highfrequency directional band gap is very unstable.