CN112201219A

CN112201219A - Mass-free diaphragm cavity coupling sound absorption structure

Info

Publication number: CN112201219A
Application number: CN202011078107.XA
Authority: CN
Inventors: 乔菁; 许启山; 李隆球; 张广玉
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2020-10-10
Filing date: 2020-10-10
Publication date: 2021-01-08

Abstract

The invention relates to the field of noise control, in particular to a mass-block-free diaphragm cavity coupling sound absorption structure which comprises a film, a grating, a back cavity and an adhesive, wherein the film does not need to be prestressed, the whole structure can ensure nearly 100% perfect absorption in a low frequency band, the problem of limited practicability in the development of a film type acoustic metamaterial is solved, and a solution is provided for the engineering application of the film metamaterial. The periphery of the film is adhered to the grating through an adhesive, and the periphery of the grating is fixed on the edge of the upper part of the back cavity. And a micron-sized thin air layer is formed between the grating and the film. The film is made of commercially available elastomers such as silicon rubber, latex and plastic, the thickness of the film is 0.1-1 mm, and tension is not required to be applied when the film is flattened. A plurality of openings are distributed on the grating.

Description

Mass-free diaphragm cavity coupling sound absorption structure

Technical Field

The invention relates to the field of noise control, in particular to a coupling sound absorption structure without a mass block diaphragm cavity.

Background

Noise pollution is a serious problem which troubles human society at present, noise control, especially the absorption of audible sound, is a very interesting research hotspot in the fields of aerospace, building environment, transportation and the like. Sounds with frequencies in excess of 1000Hz can be absorbed by conventional porous materials such as mineral wool and foam or some modified composite porous materials. However, with conventional porous materials it is difficult to absorb sound below 1000Hz, since sound absorption follows the principle of linear frequency dependent dissipation. Therefore, in order to ensure the sound absorption capability of the sound absorption material at low frequencies, the volume or thickness of the sound absorption material is generally required to be increased, which is not easily satisfied in practical applications. Micro-porous plates with back cavities are typically used for sound absorption below 1000 Hz. However, when the frequency is less than 500Hz, the thickness of the structure is typically greater than 5 cm. Additionally, sub-millimeter perforations of MPPs are typically made by laser machining techniques. Even with a medium porosity, a large number of piercing operations are required, which results in a considerable processing cost.

Since the acoustic metamaterial is proposed, it has received extensive attention and research from academia and industry due to its excellent low frequency noise control capability. Has incomparable superiority in the aspect of low-frequency broadband noise reduction, and is the mainstream development direction of the next generation of high-performance/light-weight/small-volume noise reduction material/structure with great potential.

At present, the research on noise reduction acoustic metamaterials at home and abroad strives to improve the low-broadband noise reduction capability, reduce the weight and reduce the size, and the research mainly comprises resonant cavities, thin films/thin plates, membrane cavity coupling and the like. Compared with a cavity structure with a complex structure and a compact rigidity, the membrane metamaterial with low quality advantage and excellent low-frequency effect, which is provided by researchers, is one of the most important research directions for designing the noise-reducing metamaterial in the future, the structure is mostly a resonance structure formed by a tensioning thin film and an attached mass block, and the effective mode required by a mass block adjusting system is used for realizing the noise isolation/absorption effect. But the existence of the prestress of the mass block and the thin film greatly increases the manufacturing difficulty of the mass block and the thin film, weakens the structural robustness and limits the practical application. Furthermore, the structure of the system determines that the tuning of the properties of such metamaterials will become extremely difficult.

Disclosure of Invention

The invention provides a mass block-free diaphragm cavity coupling sound absorption structure which has the advantages that a film does not need to be prestressed and an additional mass block is not needed, the problem that the practicability is limited in the development of a film type acoustic metamaterial is solved, and a solution is provided for the engineering application of the film metamaterial.

The invention relates to the field of noise control, in particular to a mass-block-free diaphragm cavity coupling sound absorption structure which comprises a film, a grating, a back cavity and an adhesive, wherein the film does not need to be prestressed, the whole structure can ensure nearly 100% perfect absorption in a low frequency band, the problem of limited practicability in the development of a film type acoustic metamaterial is solved, and a solution is provided for the engineering application of the film metamaterial.

The periphery of the film is adhered to the grating through an adhesive, and the periphery of the grating is fixed on the edge of the upper part of the back cavity.

And a micron-sized thin air layer is formed between the grating and the film.

Preferably, the material of the film is one of silicon rubber, latex and plastic, and the thickness of the film is between 0.1mm and 1 mm.

Preferably, the grid is provided with a plurality of openings.

Preferably, the opening is of an annular groove type/a straight groove type.

Preferably, the opening is a round hole/square hole type.

Preferably, the opening is of a spiral type.

Preferably, the opening is one or a combination of a plurality of annular groove type/straight groove type, round hole/square hole type and spiral line type.

Preferably, the openings are arranged in an array on a grid.

Preferably, the back cavity is one or a combination of a pure cavity, a space folding cavity or a cavity filled with porous sound absorption materials.

The invention discloses a mass block-free diaphragm cavity coupling sound absorption structure, which has the beneficial effects that:

according to the mass-block-free membrane cavity coupling sound absorption structure, prestress does not need to be applied to the membrane, the mass block is not added to the membrane, the whole structure can ensure perfect absorption of nearly 100% in a low frequency band, the problems that the membrane type acoustic metamaterial is difficult to prepare due to the fact that the mass block needs to be added and pretightening force is applied, the practicability is limited due to performance change caused by the fact that the membrane is loosened in the using process and the like are solved, and a solution is provided for engineering application of the membrane metamaterial.

Drawings

The invention is described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic view of an overall structure of a mass-free diaphragm coupling sound absorption structure according to the present invention;

FIG. 2 is a schematic view of an overall structure of a non-mass block diaphragm coupling sound absorption structure according to the present invention;

FIG. 3 is a schematic diagram of a mass-free diaphragm coupled sound absorbing structure according to the present invention, which can generate an absorption peak of approximately 100% at a low frequency band.

In the figure: a film 1; a grid 2; a back cavity 3; and (4) an adhesive.

Detailed Description

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

The first embodiment is as follows:

the embodiment is described below by combining fig. 1-2, the invention relates to the field of noise control, and more specifically relates to a mass-block-free diaphragm cavity coupling sound absorption structure which comprises a diaphragm 1, a grating 2, a back cavity 3 and an adhesive 4, wherein the diaphragm 1 does not need to be prestressed, the overall structure can ensure 100% perfect absorption in a low frequency band, the problem of limited practicability in the development of a diaphragm type acoustic metamaterial is solved, and a solution is provided for the engineering application of the diaphragm metamaterial.

The periphery of the film 1 is adhered to the grating 2 through the adhesive 4, and the periphery of the grating 2 is fixed on the upper edge of the back cavity 3. The connection between the film 1 and the grid 2 does not require a strong adhesive bond to facilitate the replacement of the film 1. The film 1 is made of soft materials with low modulus, and when the film 1 vibrates, the film can provide part of energy dissipation for the system, so that sound is effectively absorbed.

The second embodiment is as follows:

this embodiment will be described with reference to fig. 1 to 2, and the first embodiment will be further described, in which a micron-sized thin air layer is formed between the grid 2 and the film 1. The air in the air layer between the film 1 and the grid 2 rubs against the surrounding solid at resonance to generate thermal viscous energy dissipation, so the dissipation in the film 1 and the thermal viscous dissipation in the air layer constitute the total dissipation of the system, further performing sound absorption.

The third concrete implementation mode:

the present embodiment is described below with reference to fig. 1-2, and the present embodiment further describes a first specific embodiment, the material of the film 1 is one of silicon rubber, latex and plastic, the thickness is between 0.1mm and 1mm, and it is not necessary to apply a prestress to the film 1, so that the film 1 can lie flat on the grid 2.

The fourth concrete implementation mode:

the present embodiment is described below with reference to fig. 1-2, and the present embodiment further describes a first specific embodiment, in which a plurality of openings are uniformly distributed on the grid 2. The open shape contributes to further sound absorption.

The fifth concrete implementation mode:

the present embodiment will be described with reference to fig. 1-2, and the present embodiment further describes a fourth embodiment, in which the opening is an annular groove type/a straight groove type.

The sixth specific implementation mode:

this embodiment will be described with reference to fig. 1-2, and this embodiment will further describe a fourth embodiment in which the openings are circular/square holes.

The seventh embodiment:

this embodiment will be described with reference to fig. 1 to 2, and this embodiment will further describe a fourth embodiment, in which the openings are of a spiral line type.

The specific implementation mode is eight:

the fourth embodiment is further described in the following with reference to fig. 1-2, wherein the opening is one or a combination of several of an annular groove type/straight groove type, a round hole/square hole type, and a spiral line type.

The specific implementation method nine:

this embodiment will be described with reference to fig. 1-2, which further illustrates a fourth embodiment in which the openings are arranged in an array on a grid.

The detailed implementation mode is ten:

the present embodiment is described below with reference to fig. 1-2, and the present embodiment further describes a first specific embodiment, where the back cavity 3 is one or a combination of pure cavities, space folding cavities, or cavities filled with porous sound absorbing materials. The cavities in the back cavity 3 with different shapes have different sound absorption effects, and the cavities in different shapes in the back cavity 3 are selected according to requirements.

The concrete implementation mode eleven:

referring to FIG. 3, the present embodiment will be described, wherein the absorption peaks at different frequencies can be generated by the films 1 with different thicknesses, and the absorption curves of the films 1 with different thicknesses, 0.2mm, 0.3mm and 0.4mm are shown in FIG. 3, which shows the same material parameters.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and that various changes, modifications, additions and substitutions which are within the spirit and scope of the present invention and which may be made by those skilled in the art are also within the scope of the present invention.

Claims

1. The utility model provides a no quality piece diaphragm chamber coupling sound absorbing structure, includes film (1), grid (2), back chamber (3) and adhesive (4), its characterized in that: the periphery of the film (1) is adhered to the grating (2) through an adhesive (4), and the periphery of the grating (2) is fixed on the upper edge of the back cavity (3).

2. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 1, wherein: and a micron-sized thin air layer is formed between the grating (2) and the film (1).

3. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 1, wherein: the film (1) is made of one of silicon rubber, latex and plastic, and the thickness of the film is 0.1mm-1 mm.

4. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 1, wherein: a plurality of openings are distributed on the grating (2).

5. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 4, wherein: the opening is in the shape of an annular groove or a straight groove.

6. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 4, wherein: the opening is a round hole/square hole type.

7. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 4, wherein: the opening is of a spiral line type.

8. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 4, wherein: the opening is one or a combination of a plurality of annular groove type/straight groove type, round hole/square hole type and spiral line type.

9. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 4, wherein: the openings are arranged in an array on a grid.

10. The mass-free diaphragm-cavity coupled sound absorbing structure of claim 1, wherein: the back cavity (3) is internally provided with one or a combination of a pure cavity, a space folding cavity or a cavity filled with porous sound absorption materials.