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Composite sound absorption structure for improving set low frequency sound absorption performance

A sound absorption and performance technology, applied in the field of acoustics, can solve the problems of distortion or damage of sensitive components, poor low frequency sound absorption, etc., to achieve the effect of enhancing sound absorption capacity, improving sound absorption performance, and improving low frequency sound absorption performance

Inactive Publication Date: 2016-09-07
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] According to the calculation and experimental research on the sound absorption coefficient ∝ of the metal fiber felt, it is found that the metal fiber felt absorbs sound by using friction and viscous force and heat exchange effect, and has the characteristics of excellent sound absorption performance at medium and high frequencies but poor sound absorption at low frequencies; When the spacecraft takes off, due to the excessive noise, it is easy to distort or damage the sensitive components

Method used

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  • Composite sound absorption structure for improving set low frequency sound absorption performance
  • Composite sound absorption structure for improving set low frequency sound absorption performance
  • Composite sound absorption structure for improving set low frequency sound absorption performance

Examples

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example 1

[0050] In order to strengthen the sound absorption coefficient at a specific frequency of 960 Hz, the upper felt layer 1, the lower felt layer 2 and the middle felt layer 3 are all made of stainless steel metal fiber felt with a porosity of 90%, and the diameter of the felt wire is 50 μm; the film 5 is selected The modulus is 50Mp and the density is 1097kg / m 3 , the rubber material with Poisson's ratio of 0.33, the mass block 6 is selected with a modulus of 200GP and a density of 7870kg / m 3 1. An aluminum block with a Poisson's ratio of 0.3;

[0051] See attached Figure 4 , the composite sound-absorbing structure is evenly divided into a unit cell configuration, the unit cell configuration includes a through hole 4 and a film 5, when the through hole 4 is square or circular, the side length of the through hole 4 or The inner diameter is a, the thickness of the upper felt layer 1 is b1, the thickness of the lower felt layer 2 is b3, the thickness of the middle felt layer 3 i...

example 2

[0055] In order to strengthen the sound absorption coefficient at a specific frequency of 960 Hz, the upper felt layer 1, the lower felt layer 2 and the middle felt layer 3 are all made of stainless steel metal fiber felt with a porosity of 90%, and the diameter of the felt wire is 50 μm; the film 5 is selected The modulus is 50Mp and the density is 1097kg / m 3 , the rubber material with Poisson's ratio of 0.33, the mass block 6 is selected with a modulus of 200GP and a density of 7870kg / m 3 1. An aluminum block with a Poisson's ratio of 0.3;

[0056] See attached Figure 5 , the composite sound-absorbing structure is evenly divided into a unit cell configuration, the unit cell configuration includes a through hole 4 and a film 5, when the through hole 4 is formed by butting the large ends of two frustum-shaped cavities , the maximum inner diameter of the through hole 4 is a, the smallest inner diameter of the through hole 4 is c, and c is arrive Between; the overall thic...

example 3

[0060] In order to strengthen the sound absorption coefficient at a specific frequency of 200 Hz, the upper felt layer 1, the lower felt layer 2 and the middle felt layer 3 are all made of stainless steel metal fiber felt with a porosity of 90%, and the diameter of the felt wire is 50 μm; the film 5 is selected The modulus is 50Mp and the density is 1097kg / m 3 , the rubber material with Poisson's ratio of 0.33, the mass block 6 is selected with a modulus of 200GP and a density of 7870kg / m 3 1. An aluminum block with a Poisson's ratio of 0.3;

[0061] See attached Figure 4 , the composite sound-absorbing structure is evenly divided into a unit cell configuration, the unit cell configuration includes a through hole 4 and a film 5, when the through hole 4 is square or circular, the side length of the through hole 4 or The inner diameter is a, the thickness of the upper felt layer 1 is b1, the thickness of the lower felt layer 2 is b3, the thickness of the middle felt layer 3 i...

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Abstract

The invention discloses a composite sound absorption structure for improving set low frequency sound absorption performance, and belongs to the technical field of acoustics, the structure is formed by an upper felt layer, a middle felt layer and a lower felt layer which are fixedly connected in sequence; the upper felt layer, the middle felt layer and the lower felt layer are metal fiber felts; wherein the upper felt layer and the lower felt layer has the same thickness which is 1.5mm-5mm; the thickness of the middle felt layer is equal to or lower than the same of the upper felt layer and the lower felt layer; more than one through holes are uniformly arranged on the surface of the middle felt layer, the axis direction of the through holes is the same with the height direction of the middle felt layer; thin films are fixed to the internal through holes; the shape of each thin film is the same with the radial section shape of each through hole, and the thin films in all through holes are in the same plane; a mass block is fixed to each thin film; the structure is used for improving the sound absorption performance of the metal fiber felt in 0-1500Hz low frequency range, an acoustic metamaterial interlayer and the mass block are introduced to improve the material set low frequency sound absorption performance, and the structure has characteristics of adjustable frequency and good sound absorption performance.

Description

technical field [0001] The invention belongs to the technical field of acoustics, and in particular relates to a composite sound-absorbing structure for improving sound-absorbing performance at set low frequencies. Background technique [0002] Noise as a way of wave propagation has a general impact on people's daily life, especially high-speed railways, air transport and other high-speed vehicles will generate strong noise during operation, so for the comfort of passengers and the reduction of noise pollution to the environment , noise reduction is particularly important. On the other hand, in the military field, reducing the measurability of submarine engine noise and eliminating the interference of low-frequency noise on sonar is one of the key technologies to improve the survivability of submarines. [0003] The sound-absorbing materials commonly used in daily life are mostly fibrous sound-absorbing materials, granular sound-absorbing materials, foam plastic materials, ...

Claims

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Application Information

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IPC IPC(8): G10K11/172G10K11/162
CPCG10K11/162G10K11/172
Inventor 胡更开陈昌儒周萧明程勇
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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