Adjustable piezoelectric phononic crystal plate based on acoustic black hole

Abstract

The invention designs an adjustable piezoelectric phononic crystal plate based on an acoustic black hole. A piezoelectric material is used to enable a scatterer in a phononic crystal to have a negative equivalent elastic modulus, so that a point defect is caused. The local position of wave is changed by changing the position of a piezoelectric plate, and the silencing effect is enhanced at the frequency of the original forbidden band. Compared with the original traditional defective phononic crystal plate, the adjustable piezoelectric phononic crystal plate has obvious flexibility, and the position of the acoustic black hole can be changed arbitrarily without changing the material structure of the phononic crystal.

Description

technical field [0001] The invention belongs to an acoustic black hole device for controlling wave propagation, specifically an adjustable piezoelectric phononic crystal plate based on an acoustic black hole, which acts on various acoustic filters to realize the function of adjustable channel filtering, and can also It is used in structural fault detection, and as a health monitoring system for various fields. Background technique [0002] Traditional defect state phononic crystals are divided into point defects and line defects. Point defect state phononic crystals have a significant impact on the local characteristics of phononic crystals. Studies have shown that elastic waves are localized at point defects, thereby realizing the characteristics of acoustic black holes. For the band gap of phononic crystals, if point defects appear in the anechoic frequency, the noise will be greatly reduced, which will have a profound impact in practical applications, such as figure 1 It...

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Problems solved by technology

figure 2 The schematic diagram of the structure designed for this purpose, when the unit cell at A is removed, the modal cloud image calculated by COMSOL finite element software is as follows image 3 As shown in (a), when the unit cells at A and C are removed, the modal cloud image is as follows image 3 As shown in (b), it is verified that the elastic wave is indeed localized at the point defect. This design realizes the characteristics of the acoustic black hole without changing the band gap, which has strong practical value, but it also has the fixed position of the acoustic black hole , single defect state, too dependent on structural design and other disadvantages

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