Broadband wide-angle sound wave absorber based on periodic acoustic channel array

Abstract

The invention belongs to the technical field of noise suppression, provides a broadband wide-angle sound wave absorber based on a periodic acoustic channel array, and aims to solve the problem that the existing noise suppression generally has a narrow working band and is not ideal in noise suppression effect in a complicated and diversified noise environment. The multiple broadband wide-angle sound absorption units are arranged in parallel, the opening ends of the broadband wide-angle sound absorption units face the sound wave incidence direction, the sound absorption media and the channel protrusions are arranged in the acoustic channels, the sound absorption effect on 500-4000 Hz sound waves is extremely good, and when the sound waves are incident at 0-75 degrees, the average sound absorption efficiency reaches 90% or above. According to the invention, the working bandwidth and the effective incidence range of sound waves can be effectively increased.

Description

Technical Field

[0001] The invention belongs to the technical field of noise suppression, and in particular relates to a broadband and wide-angle sound wave absorber based on a periodic acoustic channel array. Background Art

[0002] Sound wave absorbers can effectively absorb incident sound waves, playing a vital role in reducing noise pollution, protecting hearing, and preventing hearing loss. In addition, they can significantly improve people's sleep quality, reduce stress and anxiety caused by noise, and thus improve overall mental health. Studies have shown that the frequency band of 500-4000Hz is the most sensitive frequency band of the human ear. Effectively suppressing noise in this frequency band can not only greatly improve people's quality of life, but also significantly improve work efficiency, especially in environments that require high concentration, such as offices, libraries or hospitals.

[0003] At present, a variety of technologies and methods have been applied in the field of noise suppression, including the installation of soundproof baffles, the use of sound-absorbing materials, and the use of acoustic adjustment devices. These technologies can reduce the spread and impact of noise to a certain extent. However, there is a common problem with existing noise suppression devices, that is, their operating frequency band is relatively narrow and it is difficult to cover the entire sensitive range of human hearing. This results in their noise suppression effect being less than ideal when facing complex and diverse noise environments. Therefore, how to develop and design sound wave absorbers that can cover a wider frequency band to more comprehensively meet people's needs for a quiet environment in different scenarios is still one of the important research directions and challenges in the field of acoustics. Summary of the invention

[0004] In view of the shortcomings of the prior art, in order to solve the problems of narrow working frequency band and limited incident angle of the current noise suppression device, the present invention provides a broadband and wide-angle sound wave absorber based on a periodic acoustic channel array, which utilizes the protruding structure and sound-absorbing medium in the acoustic channel to achieve absorption of sound waves. The present invention has an excellent absorption effect on sound waves of 500-4000Hz.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A broadband wide-angle sound absorbing unit comprises an acoustic channel and a sound absorbing medium of a porous material. The sound absorbing medium is fixed inside the acoustic channel and presents a conical structure that gradually decreases from bottom to top. The acoustic channel presents a cavity structure with one end open. A plurality of channel protrusions are arranged on the inner side of the acoustic channel tube wall, and the spacing between adjacent channel protrusions is the same.

[0007] Furthermore, the width of the acoustic channel is of the same order of magnitude as the central wavelength of the incident acoustic wave.

[0008] Furthermore, the channel protrusions have the same length and thickness of 1 mm, the channel protrusions are perpendicular to the acoustic channel tube wall, and the spacing between the channel protrusions is one third of the central wavelength of the incident sound wave.

[0009] Furthermore, a gas medium is filled between the acoustic channel and the sound absorbing medium.

[0010] A broadband wide-angle sound wave absorber based on a periodic acoustic channel array is based on the above-mentioned broadband wide-angle sound absorbing unit and includes a plurality of broadband wide-angle sound absorbing units, all of which are arranged in parallel, the outer sides of the acoustic channel tube walls of the broadband wide-angle sound absorbing units are in contact with the adjacent broadband wide-angle sound absorbing units, and the open ends of all the broadband wide-angle sound absorbing units are placed on the same side, the open ends of the broadband wide-angle sound absorbing units are located in the same plane, and the open ends face the direction of incident sound waves.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] In the periodic arrangement structure of multiple channels of the present invention, each acoustic channel has a periodic protrusion of a specific length, and each channel has a conical sound-absorbing medium as a material for absorbing sound waves. In free space, when a beam of sound waves is incident on the surface of the present invention, it will be absorbed by the composite structure formed by the channel protrusions and the conical sound-absorbing medium in the acoustic channel of the present invention. The present invention has an excellent absorption effect on sound waves of 500-4000Hz, especially in the low-frequency part near 500Hz. Compared with the previous sound wave absorber, the average sound absorption efficiency is as high as more than 90% when the sound wave is incident at 0-75°, and even at a low frequency of 500Hz, it can reach 80% of the sound absorption efficiency. The present invention can effectively increase the working bandwidth and the effective incident range of sound waves. The structure of the present invention can be used in noise pollution control, ultra-wideband sound absorption and other occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention;

[0014] Figure 2 It is a schematic structural diagram of a broadband wide-angle sound absorbing unit of the present invention;

[0015] Figure 3 It is the absorption efficiency of the present invention for sound waves in the frequency band of 500-4000 Hz at the incidence angles of 0°, 30°, and 60° respectively.

[0016] In the figure, 1-channel protrusion structure; 2-acoustic channel pipe wall; 3-sound absorbing medium. DETAILED DESCRIPTION

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some examples of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] like Figures 1 to 3 As shown, the present invention discloses a broadband wide-angle sound absorption unit, such as Figure 2 As shown, it includes an acoustic channel and a sound-absorbing medium 3 of a porous material, the sound-absorbing medium 3 is fixed inside the acoustic channel, the sound-absorbing medium 3 is in a tapered structure that gradually decreases from bottom to top, a gas medium is filled between the acoustic channel and the sound-absorbing medium 3, the acoustic channel is in a cavity structure with one end open, a plurality of channel protrusions 1 are arranged on the inner side of the acoustic channel wall 2, the adjacent channel protrusions 1 have the same spacing, the same length, and a thickness of 1 mm, the channel protrusions 1 are perpendicular to the acoustic channel wall 2, and the spacing between the channel protrusions 1 is one-third of the central wavelength of the incident sound wave; the width of the acoustic channel is of the same order of magnitude as the central wavelength of the incident sound wave.

[0019] The present invention also discloses a broadband wide-angle sound wave absorber based on a periodic acoustic channel array, based on the above-mentioned broadband wide-angle sound absorbing unit, including a plurality of broadband wide-angle sound absorbing units, all of which are arranged in parallel, the outer side of the acoustic channel wall 2 of the broadband wide-angle sound absorbing unit is in contact with the adjacent broadband wide-angle sound absorbing unit, and the opening ends of the broadband wide-angle sound absorbing units are placed on the same side, the opening ends of the broadband wide-angle sound absorbing units are located in the same plane, and the opening ends face the direction of the incident sound wave, such as Figure 1 As shown, the structure of the broadband wide-angle sound wave absorber is formed by a plurality of identical sound absorbing units arranged periodically. When in use, the present invention is placed in an air environment, and broadband sound waves incident at wide angles can be absorbed by the present invention.

[0020] The width of each channel is of the same order of magnitude as the central wavelength of the incident sound wave. There are periodic protrusions of a specific length in each channel. The sound-absorbing medium in the channel changes gradiently. The sound-absorbing medium 3 is a conical solid fixed at the bottom of the acoustic channel. The acoustic channel adopts an acoustically rigid material, which can be made of resin or metal. The sound-absorbing medium 3 adopts a porous material structure, which can be made of melamine sponge or other porous materials.

[0021] Example 1

[0022] In this example, the material of each acoustic channel wall 2 and channel protrusion 1 is resin, with a Young's modulus of 4.5 GPa and a mass density of 1117 kg / m 3 , the material of the sound absorbing medium 3 is melamine foam, the porosity is 0.995, and the flow resistance is 10.5×10 3Pa·s / m 2 The viscosity characteristic length is 240um, the thermal characteristic length is 470um, the pore tortuosity factor is 1.0059, the gas filled in the acoustic channel gap is air, the sound speed is 343m / s, and the mass density is 1.293kg / m 3 The structure of the sound wave absorber is as follows: Figure 1 As shown, several composite structure acoustic channels are arranged in parallel; the composite structure acoustic channels are as follows Figure 2 As shown, the thickness of each channel wall is 1 mm, the channel width is 9 mm, the height of the protruding structure in the channel is 2.98 mm, the thickness of the protruding structure is 1 mm, and the interval period is 5 mm.

[0023] When sound waves of different frequencies are incident at different angles, the reflected sound waves absorbed by the absorber are significantly weakened. Figure 3 The absorption efficiency of sound waves in the 500-4000 Hz frequency band when incident at 0°, 30°, and 60° respectively. It can be seen that within the range of 500-4000 Hz, the present invention can achieve an absorption efficiency of more than 80%, especially in the low-frequency part, which is significantly improved compared with previous absorbers.

[0024] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in the present invention, but will conform to the widest scope consistent with the principles and novel features disclosed in the present invention.

Claims

1. A broadband wide-angle sound absorption unit, characterized in that: The acoustic channel comprises an acoustic channel and a sound absorbing medium (3) made of a porous material. The sound absorbing medium (3) is fixed inside the acoustic channel. The sound absorbing medium (3) presents a conical structure that gradually decreases from bottom to top. The acoustic channel presents a cavity structure with one end open. A plurality of channel protrusions (1) are arranged on the inner side of the acoustic channel pipe wall (2), and the spacing between adjacent channel protrusions (1) is the same.

2. The broadband wide-angle sound absorbing unit according to claim 1, characterized in that: The width of the acoustic channel is of the same order of magnitude as the central wavelength of the incident acoustic wave.

3. The broadband wide-angle sound absorbing unit according to claim 1, characterized in that: The channel protrusions (1) have the same length and thickness of 1 mm. The channel protrusions (1) are perpendicular to the acoustic channel tube wall (2), and the spacing between the channel protrusions (1) is one third of the central wavelength of the incident sound wave.

4. The broadband wide-angle sound absorbing unit according to claim 1, characterized in that: A gas medium is filled between the acoustic channel and the sound absorbing medium (3).

5. A broadband wide-angle acoustic channel array based on periodic acoustic channel array A sound wave absorber, based on the broadband wide-angle sound absorbing unit according to any one of claims 1 to 4, characterized in that: The invention comprises a plurality of broadband wide-angle sound absorbing units, all of which are arranged in parallel, the outer sides of the acoustic channel pipe walls (2) of the broadband wide-angle sound absorbing units are in contact with the adjacent broadband wide-angle sound absorbing units, and the opening ends of all the broadband wide-angle sound absorbing units are placed on the same side, the opening ends of the broadband wide-angle sound absorbing units are located in the same plane, and the opening ends face the direction of the incident sound waves.

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