Abstract
Localized resonance phononic crystals (LRPCs) are increasingly attracting scientists’ attention in the field of low-frequency noise reduction because of the excellent subwavelength band gap characteristics in the low-frequency band. However, the LRPCs have always had the disadvantage that the noise reduction band is too narrow. In this paper, in order to solve this problem, LRPCs based on double-layer plates with cavity structures are designed. First, the energy bands of phononic crystals plate with different thicknesses were calculated by the finite element method (FEM). At the same time, the mechanism of band gap generation was analyzed in combination with the modalities. Additionally, the influence of structure on the sound transmission loss (STL) of the phononic crystals plate and the phononic crystals cavity plates were analyzed, which indicates that the phononic crystals cavity plates have notable characteristics and advantages. Moreover, this study reveals a unique ”cavity cave” pattern in the STL diagram for the phononic crystals cavity plates, and it was analyzed. Finally, the influence of structural factors on the band structure and STL of phononic crystals cavity plates are summarized, and the theoretical basis and method guidance for the study of phononic crystals cavity plates are provided. New ideas are also provided for the future design and research of phononic crystals plate along with potential applications in low-frequency noise reduction.
Highlights
Reducing low-frequency noise has always been problematic
The theoretical basis of phononic crystals was proposed by Sigalas and Economou [4] in 1992, which proved for the first time in theory that a solid spherical scattered projectile is embedded in a certain matrix material to form a three-dimensional periodic lattice structure with forbidden band elastic properties
This paper proposes phononic crystals based on double-layer plates with a cavity structure
Summary
Reducing low-frequency noise has always been problematic. The primary reason for this is that the low-frequency sound waves penetrate the structure more than the high-frequency sound waves. The theoretical basis of phononic crystals was proposed by Sigalas and Economou [4] in 1992, which proved for the first time in theory that a solid spherical scattered projectile is embedded in a certain matrix material to form a three-dimensional periodic lattice structure with forbidden band elastic properties. In 1993, Kushwaha et al [5] clearly proposed the concept of phononic crystals for the first time, and the composite medium formed by the nickel column in the aluminum alloy matrix is calculated by the plane wave method to obtain the elastic wave gap in the direction of shear polarization. A periodic material with an elastic-wave band gap is called a phononic crystals [6,7,8,9].
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