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Ultrathin multi-absorption-peak low-frequency sound absorber

A technology of absorption peak and sound absorber, which is applied in the direction of sounding equipment and instruments to achieve the effects of strong absorption, low production cost and simple structure

Active Publication Date: 2020-02-07
HARBIN ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Each of the above-mentioned cavities can only cause a quasi-perfect absorption frequency peak (in the case of the fundamental frequency), so it is very meaningful to design a quasi-perfect low-frequency sound absorber with multiple absorption peaks in a single cavity

Method used

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  • Ultrathin multi-absorption-peak low-frequency sound absorber
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  • Ultrathin multi-absorption-peak low-frequency sound absorber

Examples

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Effect test

Embodiment 1

[0042] Embodiment 1: This embodiment provides a circular ultra-thin double-absorption peak sound absorber, such as Figure 4 shown. The main body of the sound absorber is composed of a circular perforated cover plate 1, a cylindrical spiral partition plate 4 and a circular bottom plate 7 closely connected to form a spiral sound-absorbing structure, which encloses a coplanar spiral sound-absorbing cavity 5 in the middle, as The body of the sound absorber. The helical baffle 4 is inserted into the tail of the helical structure to block the irregular rectangular channel and avoid additional acoustic impedance. The perforated baffle 3 is inserted into the helical structure, and the distance L1 from the axis of the helical baffle 4 can be adjusted freely. On the circular perforated cover plate 1 and the perforated baffle plate 3, an embedded annular hole 2 of different size (with a diameter of d i , with length t i , i=1, 2 represent the ordinal number of the embedded circular ...

Embodiment 2

[0054] Embodiment 2: in embodiment 1, all are the samples of double absorption peaks, in order to prove that the sound absorber can produce more absorption peaks, the present embodiment is according to figure 1 The multi-absorption peak structure shown is a sound absorber with three absorption peaks and four absorption peaks. The specific parameters are shown in Table 2:

[0055]

[0056] Figure 7 and Figure 8 The absorption coefficients of the three-absorption peak sound absorber sample B and the four-absorption peak sample C are shown respectively. The absorption peaks of sample B are 146Hz, 442Hz and 653Hz respectively, and the sound absorption coefficients are all above 0.98. The absorption peaks of sample C are 146Hz, 417Hz, 671Hz and 921Hz respectively, and the absorption coefficients are all above 0.97. It can be seen from the figure that the degree of agreement between theory and simulation is high, and the error is not more than 2%. Moreover, the shapes of sa...

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Abstract

The invention discloses an ultrathin multi-absorption-peak low-frequency sound absorber, aims to solve the problem that each cavity of a low-frequency sound absorber can only cause one quasi-perfect absorption frequency peak, and belongs to the technical field of sound wave processing. The ultrathin multi-absorption-peak low-frequency sound absorber comprises a perforated cover plate, an embeddedround hole, a helical partition plate, a non-perforated baffle plate, a bottom plate and one or more perforated baffle plates, wherein a through hole is formed in the center of the perforated cover plate; the helical partition plate comprises a cylindrical shell and a helical structure; the helical structure is placed in the cylindrical shell; the tail part of the helical structure is connected with the inner wall of the cylindrical shell, thereby forming a helical channel; the helical partition plate is placed between the perforated cover plate and the bottom plate, and a sound absorption cavity is formed inside the helical partition plate; the non-perforated baffle plate is inserted between the outermost circle of the helical structure and a cylindrical wall; the non-perforated baffle plate is used for isolating channels of different widths; and a plurality of embedded round holes of different sizes are formed under the through hole of the perforated cover plate and above the throughhole of the perforated baffle plate to form sound absorbers of different wavelengths, thereby realizing the multi-absorption-peak low-frequency sound absorber.

Description

technical field [0001] The invention specifically relates to an ultra-thin quasi-perfect low-frequency sound absorber with multiple absorption peaks, belonging to the technical field of sound wave processing. Background technique [0002] For decades, due to the large wavelength of low-frequency (<1000Hz) sound waves, the interaction between thinner sound-absorbing materials or structures and the air medium is weaker, resulting in low sound energy dissipation efficiency, so low-frequency sound absorption and noise reduction has always been an important issue. A challenging subject. Traditional sound-absorbing materials such as porous materials, micro-perforated panels, and sound-absorbing wedges have poor absorption performance for low-frequency sound. For this, different approaches have been proposed, such as gradient porous materials, multilayer structures or material microstructure optimization. Using these methods can improve the sound absorption performance to a ce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10K11/172
CPCG10K11/172
Inventor 刘盛春孔德强李勇刘博韬曹国昕麻宇祥吕航
Owner HARBIN ENG UNIV
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