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Two-dimension phonon structure of scatterer with gap characteristic and material with gap composed by the same

A two-dimensional phonon and scatterer technology, applied in the direction of sound-generating devices, instruments, etc., can solve problems such as artificial setting defects, and achieve the effect of widening the band gap frequency range and low cost

Inactive Publication Date: 2008-12-24
XI AN JIAOTONG UNIV
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Problems solved by technology

[0006] (3) Man-made defects

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  • Two-dimension phonon structure of scatterer with gap characteristic and material with gap composed by the same
  • Two-dimension phonon structure of scatterer with gap characteristic and material with gap composed by the same
  • Two-dimension phonon structure of scatterer with gap characteristic and material with gap composed by the same

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Embodiment Construction

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0019] see figure 1 , Diffuser material selection: ordinary seamless steel pipe, steel elastic modulus: 205e9Pa, Poisson's ratio: 0.28, density: 7850kg / m 3 , Round tube outer diameter: Ф31mm, wall thickness: 3mm, length: 540mm, number of slits: 3, slit distance D: 8mm, slit width W (three types): 6mm, 4mm, 2mm. Substrate: Air. Use a common lathe to process the outer cylindrical positioning surface of the steel pipe, use a fast engraving and milling machine to cut slits, and assemble the processed diffusers in 3 rows and 2 columns for each slit width (see figure 1 , 3), its arrangement can be regular arrangement or staggered arrangement. The results of experimental tests and theoretical calculations are as follows: Figure 5 shown: Figure 5 The transmission coefficient curve in Fig. 1 shows that the slotted cylindrical scatterer structure proposed in this...

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Abstract

The invention provides a two-dimensional phonon structure provided with lacune feature scatterers and a band gap material of the structure. Under the condition that the parameter condition (such as lattice constant, material component etc.) does not change, a strip or more strips of hair cracks used for sound absorption are opened on the scatterer. The acoustic band gap characteristics with relatively wide band gap and relatively low initial frequency can be realized by adopting the structure. Compared with the prior two-dimensional phonon structure with the acoustic band gap characteristics, under the condition of keeping the original parameters of phononic crystals unchanged, the structure of the invention fulfills the purpose of widening the range of band gap and reducing the initial frequency of band gap through opening cracks on the scatters. On the basis of Bragg scattering and local resonance principles, a hair crack anechoic mechanism is added and the initial frequency and width of the band gap are adjusted by changing the parameters (number, width and position) of cracks, thus obtaining better acoustic band gap characteristics compared with the original phonon structure.

Description

technical field [0001] The invention belongs to the category of machinery, and in particular relates to a two-dimensional phonon structure with a gap characteristic scatterer and a bandgap material composed thereof, which is applied to acoustics, urban environment, industrial noise control and aviation noise control. Background technique [0002] In urban and industrial noise control, classical sound absorption and sound insulation technologies are still mainly used at present, such as the design of sound insulation structures according to the quality theorem. Since the 1990s, with the discovery and development of phononic crystals, people have begun to pay attention to the application of phononic crystal technology to design and fabricate sound insulating structures with acoustic band gap properties. In phononic crystals, the density ratio, sound velocity ratio, physical parameter ratio (elastic modulus, etc.) of the matrix and the scatterer can be increased, or by changing...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10K11/16
Inventor 陈天宁崔战友张波吴钊
Owner XI AN JIAOTONG UNIV