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Gradational-section low-frequency sound absorber design method

A design method and sound-absorbing body technology, applied in the direction of sound-emitting devices and instruments, can solve the problems of complicated adhesion and increased difficulty of prestressed additional decorative quality

Active Publication Date: 2019-02-01
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For example, the widely studied decorative thin-film resonator [Mei, J., et al., Nat.Commun.3(2):756], which is composed of a soft film and an additional small mass, can operate at 100Hz-1000Hz Good sound absorption can be achieved in the frequency band, but the addition of prestress and the adhesion of decorative quality in the process of processing are relatively complicated, which increases the difficulty of actual production and manufacturing.

Method used

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  • Gradational-section low-frequency sound absorber design method
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  • Gradational-section low-frequency sound absorber design method

Examples

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Embodiment 1

[0074] In order to compare the advantages of the sound-absorbing body with gradual cross-section, this embodiment follows the figure 1 The shown design process designs three absorbers with different gradient types (exponential, linear and uniform), and compares their sound absorption performance. The specific steps are:

[0075] Step 1: Determine the sound absorption frequency. Because the purpose of this implementation is to compare the advantages of the sound-absorbing body with gradual cross-section, the shape of the sound-absorbing body is preset as L×W×H=60mm×20mm×50mm, and under this shape condition, the sound-absorbing body of each gradient type is designed In the case of the same coefficient (greater than 99%), the sound absorbing body with gradual cross section can reach the lowest sound absorption frequency.

[0076] Step 2: Determine the gradient type according to the processing accuracy and the frequency range to be absorbed. Specifically, in terms of sound abs...

Embodiment 2

[0085]In different acoustic environments, the noise frequency is not the same. Therefore, sound-absorbing bodies with fixed shapes and different peak sound-absorbing frequencies have high practical value in installation and application. In broadband noise application scenarios, a single narrow-band sound absorber cannot achieve the ideal sound absorption effect, and by installing two or more of the above-mentioned sound absorbers with fixed shapes and different peak sound absorption frequencies side by side, the sound absorption bandwidth can be further expanded.

[0086] This example uses figure 1 The steps described in the above design two sound-absorbing bodies with different peak sound-absorbing frequencies but the same shape, the specific parameters are shown in Table 2. Figure 5a is a cross-sectional schematic diagram of two sound-absorbing bodies installed side by side, Figure 5b The relationship between the absorption coefficient and the frequency when two sound a...

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Abstract

The invention discloses a gradational-section low-frequency sound absorber design method. By constructing a gradational section structure folded in space, the sound absorber can thus absorb low-frequency sound waves effectively by utilizing structural resonance and air thermal viscous effects. Compared with the traditional uniform channel sound absorber, the sound absorber constructed by the method can achieve a lower sound absorption frequency in the same volume, and can change the sound absorption frequency without changing the shape. By installing a plurality of sound absorbers with different peak absorption frequencies in parallel, low-frequency broadband sound absorption at a sub-wavelength scale can be realized. In summary, the sound absorber constructed by the method of the invention has the characteristics of simple structure, low processing difficulty and easy installation and use.

Description

technical field [0001] The invention belongs to the fields of noise control and architectural acoustics, and relates to a design method of a low-frequency sound absorbing body, more specifically, to a method for effectively absorbing low-frequency sound waves by using gradient structural resonance and air thermoviscous effect. Background technique [0002] Noise has a great negative impact on human beings and their production and life. Continuous noise may affect people's hearing and nervous system to varying degrees. Over the years, many related noise reduction technologies have come out one after another. In the field of passive technology, there are technologies such as traditional porous sound-absorbing materials and micro-perforated plates. ) energy, their thickness will reach a size comparable to the wavelength, which limits the scope of use of this type of sound absorber; in the field of active technology, a series of technologies represented by active noise control c...

Claims

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Application Information

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IPC IPC(8): G10K11/172
CPCG10K11/172
Inventor 郭霞生申雨晨杨嫣烨章东
Owner NANJING UNIV
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