CN113674727A - Deep sub-wavelength low-frequency sound absorption structure and sound absorption unit - Google Patents
Deep sub-wavelength low-frequency sound absorption structure and sound absorption unit Download PDFInfo
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- CN113674727A CN113674727A CN202110896565.2A CN202110896565A CN113674727A CN 113674727 A CN113674727 A CN 113674727A CN 202110896565 A CN202110896565 A CN 202110896565A CN 113674727 A CN113674727 A CN 113674727A
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
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- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
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- Building Environments (AREA)
Abstract
The invention relates to the technical field of noise control, and provides a deep sub-wavelength low-frequency sound absorption structure and a sound absorption unit, wherein the sound absorption structure comprises a sound absorber, the sound absorber comprises a sound absorption base body, the sound absorption base body is enclosed into a shell, a hollow sound absorption back cavity is arranged in the shell, and the deep sub-wavelength low-frequency sound absorption structure further comprises: the negative stiffness structural member is compounded with the sound absorption base body. The invention can realize low-frequency broadband sound absorption on the deep sub-wavelength thickness; the invention has simple structure, easy processing, integral forming, convenient installation, low cost, no pollution, light weight and good fireproof performance, and is suitable for noise reduction treatment of low-frequency sound waves of aerospace, rail transit, power plants and the like and noise protection of building environments.
Description
Technical Field
The invention relates to the technical field of noise control, in particular to a deep sub-wavelength low-frequency sound absorption structure and a sound absorption unit.
Background
The sound absorber is used for absorbing sound and reducing noise, and mainly comprises a film or thin plate type sound absorber, and comprises a shell and a mass block, wherein the shell is surrounded by a sound absorption base body, the sound absorption base body is a film or a thin plate, a hollow sound absorption back cavity is arranged in the shell, and the mass block is arranged on the sound absorption base body. However, the existing sound absorber has limited sound absorption bandwidth, and needs a thicker sound absorption back cavity to realize sound absorption, so that the whole structure has larger thickness, and deep sub-wavelength sound absorption and broadband sound absorption are difficult to realize.
Disclosure of Invention
The invention provides a deep sub-wavelength low-frequency sound absorption structure and a sound absorption unit, which can realize low-frequency broadband sound absorption on the thickness of deep sub-wavelength.
The invention provides a deep sub-wavelength low-frequency sound absorption structure, which comprises a sound absorber, wherein the sound absorber comprises a sound absorption base body, the sound absorption base body is enclosed into a shell, a hollow sound absorption back cavity is arranged in the shell, and the deep sub-wavelength low-frequency sound absorption structure further comprises: the negative stiffness structural member is compounded with the sound absorption base body.
The deep sub-wavelength low-frequency sound absorption structure further comprises a connecting piece, and the negative stiffness structural part is connected with the sound absorption base body through the connecting piece.
According to the deep sub-wavelength low-frequency sound absorption structure provided by the invention, the sound absorption substrate is a film or a thin plate.
According to the deep sub-wavelength low-frequency sound absorption structure provided by the invention, at least one negative stiffness structural part is arranged.
According to the deep sub-wavelength low-frequency sound absorption structure provided by the invention, the negative stiffness structural part is positioned on one side or two sides of the sound absorption substrate.
According to the deep sub-wavelength low-frequency sound absorption structure provided by the invention, the sound absorption substrate is the negative stiffness structural part.
According to the deep sub-wavelength low-frequency sound absorption structure provided by the invention, the deep sub-wavelength low-frequency sound absorption structure is integrally formed by 3D printing or assembled and formed by machining.
The invention also provides a sound absorption unit which comprises a plurality of deep sub-wavelength low-frequency sound absorption structures.
According to the deep sub-wavelength low-frequency sound absorption structure and the sound absorption unit, the negative rigidity structural member is compounded with the sound absorption base body of the sound absorber, so that the rigidity of the whole sound absorption structure is reduced, and the low-frequency broadband sound absorption with deep sub-wavelength thickness is realized; the invention has simple structure, easy processing, integral forming, convenient installation, low cost, no pollution, light weight and good fireproof performance, and is suitable for noise reduction treatment of low-frequency sound waves of aerospace, rail transit, power plants, machining and the like and noise protection of building environments.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the related art, the drawings needed to be used in the description of the embodiments or the related art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic view of a deep sub-wavelength low frequency sound absorption structure provided by the present invention;
FIG. 2 is a negative stiffness test chart of the negative stiffness beam provided by the present invention;
FIG. 3 is a graph comparing sound absorption coefficients of finite element simulations of deep sub-wavelength low frequency sound absorbing structures provided by the present invention with conventional sheet-type sound absorbers;
reference numerals:
1: a sound absorbing matrix; 2: a negative stiffness structural member; 3: a connecting member; 4: an acoustic backing cavity.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the embodiments of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be configured in a specific orientation, and operate, and thus, should not be construed as limiting the embodiments of the present invention.
In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. Specific meanings of the above terms in the embodiments of the present invention can be understood in specific cases by those of ordinary skill in the art.
In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
According to an embodiment of the present invention, as shown in fig. 1, the deep sub-wavelength low-frequency sound absorption structure provided by the present invention mainly includes: a sound absorber and a negative stiffness structure 2. The sound absorber comprises a sound absorption base body 1, the sound absorption base body 1 is enclosed into a shell, and a hollow sound absorption back cavity 4 is arranged in the shell; the negative stiffness structural member 2 is composited with a sound absorption base 1 of the sound absorber.
According to the embodiment of the invention, the negative stiffness structural part 2 is compounded with the sound absorption base body 1 of the sound absorber, namely, the stiffness of the whole sound absorption structure can be reduced by introducing the negative stiffness structural part 2, so that the sound absorption frequency moves to low frequency, and the low-frequency broadband sound absorption with deep sub-wavelength thickness is realized; the invention has simple structure, easy processing, integral forming, convenient installation, low cost, no pollution, light weight and good fireproof performance, and is suitable for noise reduction treatment of low-frequency sound waves of aerospace, rail transit, power plants, machining and the like and noise protection of building environments.
In addition, the deep sub-wavelength low-frequency sound absorption structure can realize low-frequency broadband sound absorption with deep sub-wavelength thickness under the condition of thinner sound absorption back cavity 4 thickness compared with the prior art.
The compounding manner of the negative stiffness structural member 2 of the present invention and the sound-absorbing base 1 of the sound absorber is not particularly limited as long as both can be combined.
In one embodiment, the negative stiffness structure 2 is composited in direct contact with the sound absorbing matrix 1.
In one embodiment, the deep sub-wavelength low-frequency sound absorption structure further comprises a connecting piece 3, and the negative stiffness structural piece 2 is connected with the sound absorption base body 1 through the connecting piece 3 for compounding. According to the embodiment of the invention, the negative rigidity structural member 2 and the sound absorption substrate 1 can be effectively connected through the connecting piece 3, and the rigidity coupling effectiveness of the negative rigidity structural member and the sound absorption substrate is ensured.
The specific type of the connector 3 of the present invention is not particularly limited as long as it can function as a connector, and may be, for example, a steel connector.
In one embodiment, the negative stiffness structure 2 is located within the sound absorber, which may improve the aesthetics of the overall sound absorbing structure and facilitate protection of the negative stiffness structure 2.
It should be understood that the negative stiffness structural member 2 of the present invention is compounded on the sound absorption substrate 1 and can be used as a mass block at the same time, thereby omitting the mass block in the existing sound absorber, making the sound absorption structure simpler, reducing the cost and being more convenient to process.
According to the embodiment of the invention, the sound absorption base body 1 of the sound absorber is provided with the reinforcing ribs (not shown in the figure) to improve the rigidity of the sound absorber, so that the material of the negative rigidity structural member 2 is selected more widely, and the stability of the whole structure is improved. In other examples, the sound-absorbing base body 1 of the sound absorber may not be provided with the reinforcing ribs, and may be selected according to actual conditions.
According to an embodiment of the invention, the thickness of the sound-absorbing matrix 1 does not exceed 5 mm; the specific shape of the sound absorber casing is not particularly limited, and when the sound absorber casing is square, the length does not exceed 1000 mm.
According to an embodiment of the invention, the sound-absorbing matrix 1 is a film or a sheet.
In some examples, the film material includes plastic film, latex film, silicone film, polyester film, nylon film, PTFE film, ETFE film, and the like; the thin plate comprises aluminum plate, iron plate, steel plate, copper plate, wood plate, plastic plate, paper plate, nylon plate, etc.
According to the embodiment of the present invention, the negative rigidity structural member 2 is provided with at least one, and may be plural.
According to an embodiment of the present invention, the negative stiffness structure 2 is located on one or both sides of the sound absorbing matrix 1.
It can be understood that the present invention can combine the negative stiffness structural members 2 on at least one sound absorption substrate 1 of the sound absorber, and the negative stiffness structural members 2 on each sound absorption substrate 1 can be arranged on the inner side or the outer side or both sides, and can be adjusted according to the actual working conditions.
In one specific example, as shown in fig. 1, the negative stiffness structural member 2 is provided as one, and is disposed inside the sound absorber, i.e., inside (below) the sound absorbing base 1 at the top, and may be disposed outside (above) the sound absorbing base 1.
The specific type of the negative stiffness structural member 2 of the present invention is not particularly limited, and the negative stiffness structural member may be a structural member having a negative stiffness characteristic, for example, a negative stiffness beam or a negative stiffness plate, and the negative stiffness beam and the negative stiffness plate may be made of a steel material.
In one embodiment, the negative stiffness beam has the same length as the sound absorbing matrix 1 and a thickness of no more than 10 mm. Specifically, the length of the negative stiffness beam is 1-1000mm, the width of the negative stiffness beam is 0.1-100mm, and the thickness of the negative stiffness beam is not more than 5 mm.
In one embodiment, the negative stiffness plate has the same length as the sound absorbing matrix 1 and the negative stiffness plate has the same thickness as the sound absorbing matrix 1.
In some examples, a negative stiffness beam may achieve negative stiffness by applying pre-stress or electromagnetic force along the length of the beam, or by piezoelectric effect, as shown in fig. 2.
And the negative stiffness plate can realize negative stiffness by applying pre-pressure or electromagnetic acting force to the plate surface or by piezoelectric effect.
In addition, the negative stiffness structural member 2 may also be formed of combined compression springs, in addition to the negative stiffness beam and the negative stiffness plate, wherein the specific number and position of the combined compression springs are not particularly limited as long as they are combined with the sound absorbing base 1 of the sound absorber.
According to the embodiment of the invention, the sound absorption substrate 1 of the sound absorber is the negative stiffness structural member 2, namely the sound absorption structure of the invention integrally adopts the negative stiffness structural member 2, so that the low-frequency broadband sound absorption effect of the deep sub-wavelength thickness is further improved.
According to the embodiment of the invention, the deep sub-wavelength low-frequency sound absorption structure is integrally formed by 3D printing, the processing is convenient and fast, and the overall performance is better; of course, other machining methods can be adopted for assembly and molding.
As shown in fig. 3, the comparison of the sound absorption coefficient of the finite element simulation of the deep sub-wavelength low-frequency sound absorption structure of the present invention and the conventional sheet type sound absorber is shown, at this time, the deep sub-wavelength low-frequency sound absorption structure of the present invention is a sheet type sound absorber of the composite negative stiffness structural member 2, and under the same thickness of the sound absorption back cavity 4 (for example, 20mm), the sound absorption peak value of the deep sub-wavelength low-frequency sound absorption structure of the present invention is significantly shifted to the low frequency, so as to achieve the noise control effect of the lower frequency than that of the conventional sound absorber. In this example, the specific material selection is: the sheet metal selects 0.2mm thickness's aluminum plate, and connecting piece 3 is 2mm high steel matter, and negative rigidity structure 2 is the negative stiffness roof beam, and it is 1mm thick, 5mm wide steel matter, and the length direction precompression displacement of negative stiffness roof beam is 0.01 mm. It is to be noted that the same effects as described above are obtained for the conventional film type sound absorber and other negative rigidity structural members 2.
The invention also provides a sound absorption unit which comprises a plurality of deep sub-wavelength low-frequency sound absorption structures, so that a large-area sound absorption structure is formed, and the sound absorption effect is improved.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. The utility model provides a dark subwavelength low frequency sound absorption structure, includes the sound absorber, the sound absorber includes the sound absorption base member, the sound absorption base member encloses into the casing, be equipped with hollow sound absorption back of the body chamber in the casing, its characterized in that, dark subwavelength low frequency sound absorption structure still includes: the negative stiffness structural member is compounded with the sound absorption base body.
2. The deep subwavelength low frequency sound absorbing structure of claim 1, further comprising a connector through which the negatively stiff structure is connected to the sound absorbing matrix.
3. The structure of claim 1, wherein the sound absorbing matrix is a film or sheet.
4. The deep subwavelength low frequency sound absorbing structure of claim 1, wherein the negative stiffness structure is provided with at least one.
5. The deep subwavelength low frequency sound absorbing structure of claim 1, wherein the negative stiffness structure is located on one or both sides of the sound absorbing matrix.
6. The deep subwavelength low frequency sound absorbing structure of claim 1, wherein the sound absorbing matrix is the negatively stiff structure.
7. The deep sub-wavelength low frequency sound absorbing structure according to any one of claims 1 to 6 wherein the deep sub-wavelength low frequency sound absorbing structure is integrally formed by 3D printing or assembled by machining.
8. A sound-absorbing unit comprising a plurality of deep sub-wavelength low frequency sound-absorbing structures according to any one of claims 1-7.
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| CN202110896565.2A CN113674727A (en) | 2021-08-05 | 2021-08-05 | Deep sub-wavelength low-frequency sound absorption structure and sound absorption unit |
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| CN202110896565.2A CN113674727A (en) | 2021-08-05 | 2021-08-05 | Deep sub-wavelength low-frequency sound absorption structure and sound absorption unit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113903321A (en) * | 2021-12-09 | 2022-01-07 | 北京市科学技术研究院城市安全与环境科学研究所 | Low pressure back of body chamber sound absorption unit and building wall |
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