CN215220252U - Low-frequency broadband acoustic metamaterial composite sound absorption device - Google Patents
Low-frequency broadband acoustic metamaterial composite sound absorption device Download PDFInfo
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- CN215220252U CN215220252U CN202121297551.0U CN202121297551U CN215220252U CN 215220252 U CN215220252 U CN 215220252U CN 202121297551 U CN202121297551 U CN 202121297551U CN 215220252 U CN215220252 U CN 215220252U
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Abstract
The utility model discloses a low-frequency broadband acoustic metamaterial composite sound absorption device, which comprises an A-area perforated plate, a B-area perforated plate and a C-area perforated plate; the first channel is defined by the basic cabin body, the first partition plate and the second partition plate, the second channel is defined by the basic cabin body, the upper side of the first partition plate, the second partition plate, the upper side of the third partition plate and the fourth partition plate, and the third channel is defined by the basic cabin body, the lower side of the first partition plate, the lower side of the third partition plate and the fourth partition plate; the first channel inlet is communicated with the perforated plate in the area A, the second channel inlet is communicated with the perforated plate in the area B, and the third channel inlet is communicated with the perforated plate in the area C; the length of the first channel is greater than that of the second channel, the length of the second channel is greater than that of the third channel, and a first channel porous structure, a second channel porous structure and a third channel porous structure are respectively filled in the first channel, the second channel and the third channel. The utility model discloses have good low frequency broadband sound absorption performance and make and install simply.
Description
Technical Field
The utility model relates to a vibration and noise control technical field, more specifically say, in particular to compound sound absorbing device of low frequency broadband acoustics metamaterial.
Background
With the development and progress of the society, the demand of acoustic quality in the fields of modern delivery vehicles (automobiles, rail trains, airplanes, ships, manned spacecrafts, engineering vehicles and the like), intelligent household appliances, high-tech electronics (air conditioners, refrigerators, noise reduction earphones and the like), energy sources, buildings, human living engineering and the like is more and more urgent, so that the control requirements on full-band noise (low, medium and high frequency) are provided. The medium-high frequency noise has short corresponding wavelength and weak transmission capability, and can be effectively controlled by the traditional sound absorption material technology; however, because the wavelength of the sound wave corresponding to the low-frequency noise (below 1000Hz, especially below 500 Hz) is large and the transmission capability is strong, the traditional sound absorption material technology can only control the low-frequency noise by greatly improving the thickness/weight of the material, and how to effectively inhibit the low-frequency noise and realize the high-efficiency broadband sound absorption is a big problem in academic and engineering industries.
In recent years, the acoustic metamaterial structure proposed and developed in the field of acoustic physics and condensed state physics provides a new idea for solving the problems of low-frequency sound absorption and noise reduction. The acoustic metamaterial structure is a novel composite structure which is designed manually and specially, and can obtain extraordinary physical characteristics (such as negative equivalent mass density, negative equivalent modulus, double negative and the like) which are not possessed by the traditional material/structure, and can realize extraordinary control of low-frequency elastic waves and acoustic waves, so that the acoustic metamaterial structure has wide application value in the field of low-frequency vibration reduction and noise reduction. The traditional acoustic metamaterial sound absorption structure mainly comprises a thin-film type acoustic metamaterial structure, a Helmholtz resonance type acoustic metamaterial structure and a labyrinth type channel acoustic metamaterial structure; the design of these structures has many advantages, but also has some disadvantages, such as: the thin film type acoustic metamaterial structure is troublesome to mount (usually, an additional fixing frame is needed), the application of prestress is difficult, and the thin film is easily damaged and fails due to external influence when being used under the condition that the thin film is exposed outside; the Helmholtz resonance type acoustic metamaterial structure has a narrow action frequency band, although the labyrinth type channel acoustic metamaterial structure channel can be bent and folded to save a depth space, the bending is complex, the processing difficulty is high, the surface density is increased, and the weight and the cost are increased. These drawbacks and deficiencies clearly limit the engineering applications of conventional acoustic metamaterial sound absorbing structures.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a compound sound absorbing device of low frequency broadband acoustics metamaterial to overcome the defect that prior art exists.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a low-frequency broadband acoustic metamaterial composite sound absorption device comprises a basic cabin body, a micro-perforated plate, a first partition plate, a second partition plate, a third partition plate, a fourth partition plate, a first channel, a second channel and a third channel, wherein the micro-perforated plate comprises a zone perforated plate, a zone perforated plate and a zone perforated plate, and the zone perforated plate, the zone perforated plate and the zone perforated plate are respectively provided with a micro-perforation; the first partition plate, the second partition plate, the third partition plate and the fourth partition plate are arranged in the basic cabin body, the first channel is defined by the basic cabin body, the first partition plate and the second partition plate, the second channel is defined by the basic cabin body, the upper side of the first partition plate, the second partition plate, the upper side of the third partition plate and the upper side of the fourth partition plate, and the third channel is defined by the basic cabin body, the lower side of the first partition plate, the lower side of the third partition plate and the lower side of the fourth partition plate; the first channel inlet is communicated with the zone perforated plate, the second channel inlet is communicated with the zone perforated plate, and the third channel inlet is communicated with the zone perforated plate; the length of the first channel is greater than that of the second channel, the length of the second channel is greater than that of the third channel, and a first channel porous structure, a second channel porous structure and a third channel porous structure are respectively filled in the first channel, the second channel and the third channel.
Further, if the micro-perforations with the same diameter are arranged on the perforated plate with the area A, the perforated plate with the area B and the perforated plate with the area C, the number of the micro-perforations on the perforated plate with the area A and the number of the micro-perforations on the perforated plate with the area C are both greater than the number of the micro-perforations on the perforated plate with the area B.
Further, if the microperforations with different diameters are arranged on the perforated plate in the area a, the perforated plate in the area B and the perforated plate in the area C, the perforation rate of the microperforations on the perforated plate in the area a and the perforation rate of the microperforations on the perforated plate in the area B are both smaller than the perforation rate of the microperforations on the perforated plate in the area C.
Further, the first channel is a straight channel and the cross-sectional dimension of the first channel does not vary by more than 20%; the second channel is a bent channel, the number of bends of the bent channel is two, the size of the cross section of each section of the bent channel is not more than 20%, and the size of the cross section of each section of the bent channel is different and is not more than 50%; the third channel is a bent channel, the number of bends of the bent channel is three, the size of the cross section of each section of the bent channel is not more than 20%, and meanwhile, the size of the cross section of one section of the bent channel is different from that of the other two sections of the bent channel, and the size change is not more than 50%.
Further, the cross-sectional shapes of the first channel, the second channel and the third channel are square or circular.
Further, the cross-sectional shape of the basic cabin body is square or circular, an opening is formed in a communication area of the basic cabin body and the micro-perforated plate, and the size of the opening is the same as the area of the micro-perforated plate.
Furthermore, the front section of the first channel is filled with a first channel fluid, the rear section of the first channel is filled with a first channel porous structure, and the first channel fluid is respectively communicated with the zone perforated plate and the first channel porous structure.
Further, the front section of the second channel is filled with a second channel fluid, and the rear section of the second channel is completely filled with a second channel porous structure or the rear section of the second channel is filled with the second channel porous structure and the second channel fluid; the front section of the third channel is filled with a third channel fluid, and the rear section of the third channel is completely filled with a third channel porous structure or is filled with the third channel porous structure and the third channel fluid
Furthermore, the material of the micro-perforated plate is a metal material or a non-metal material, the material of the basic cabin, the material of the first partition plate, the material of the second partition plate, the material of the third partition plate and the material of the fourth partition plate are a metal material or a non-metal material, and the material of the first channel porous structure, the material of the second channel porous structure and the material of the third channel porous structure are polyimide, melamine, polyurethane, foam metal, glass fiber, stainless steel fiber, slag wool or polyester wool.
The principle of the utility model is that: the first channel is communicated with the A-zone perforated plate to form a first resonant cavity, the second channel is communicated with the B-zone perforated plate to form a second resonant cavity, the third channel is communicated with the C-zone perforated plate to form a third resonant cavity, the resonant frequencies of the three resonant cavities are lower, and the resonant frequency of the first resonant cavity is greater than that of the second resonant cavity and that of the third resonant cavity. Meanwhile, the sound waves entering the corresponding channels meet the porous structures filled in the channels and enter the holes of the porous structures to move back and forth for friction, and the energy of the consumed sound waves is absorbed in a heat energy mode; in addition, the local resonance in the cavity can cause that the friction of sound waves in the porous structure is aggravated near the resonance frequency, the energy dissipation is enhanced, the absorption dissipation frequency band is further widened, and finally, the three resonance frequency bands are cooperatively coupled together to form a low-frequency broadband absorption dissipation coupling mode.
Compared with the prior art, the utility model has the advantages of: the utility model is used for low frequency broadband sound absorption falls makes an uproar, has good low frequency broadband sound absorption performance to make and simple installation, the size is little, the environmental protection, with low costs, the reliability is high, has overcome the processing that traditional metamaterial structural design scheme faced and has installed complicated, with high costs and reliability a lot of shortcomings such as poor.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of the low-frequency broadband acoustic metamaterial composite sound absorption device of the present invention.
Fig. 2 is a schematic structural diagram of a micro-perforated plate according to the present invention.
Fig. 3 is a schematic structural diagram of the first channel of the present invention.
Fig. 4 is a schematic structural diagram of the second channel of the present invention.
Fig. 5 is a schematic structural diagram of a third channel in the present invention.
Fig. 6 is a schematic view of the shape of one embodiment of the channel of the present invention.
Fig. 7 is a schematic view of another embodiment of the shape of the channel of the present invention.
Fig. 8 is a graph of sound absorption coefficient for an embodiment of the present invention.
In the figure: the device comprises a basic cabin body 1, a micro-perforated plate 2, a first partition plate 3, a second partition plate 4, a third partition plate 5, a fourth partition plate 6, a first channel 7, a second channel 8, a third channel 9, a perforated plate 2a in a region A, a perforated plate 2B in a region B, a perforated plate 2C in a region C, a micro-perforated plate 2d, a first channel fluid 7a, a first channel porous structure 7B, a second channel fluid 8a, a second channel porous structure 8B, a third channel fluid 9a and a third channel porous structure 9B.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and the scope of the present invention can be more clearly and clearly defined.
Referring to fig. 1, the embodiment discloses a low-frequency broadband acoustic metamaterial composite sound absorption device, which comprises a basic cabin body 1, a micro-perforated plate 2, a first partition plate 3, a second partition plate 4, a third partition plate 5, a fourth partition plate 6, a first channel 7, a second channel 8 and a third channel 9, wherein the micro-perforated plate 2 comprises an area a perforated plate 2a, an area B perforated plate 2B and an area C perforated plate 2C, and micro-perforations 2d are arranged on the area a perforated plate 2a, the area B perforated plate 2B and the area C perforated plate 2C; the first partition plate 3, the second partition plate 4, the third partition plate 5 and the fourth partition plate 6 are arranged in the basic cabin body 1, the first channel 7 is enclosed by the basic cabin body 1, the first partition plate 3 and the second partition plate 4, the second channel 8 is enclosed by the basic cabin body 1, the upper side of the first partition plate 3, the upper side of the second partition plate 4, the upper side of the third partition plate 5 and the upper side of the fourth partition plate 6, and the third channel 9 is enclosed by the basic cabin body 1, the lower side of the first partition plate 3, the lower side of the third partition plate 5 and the lower side of the fourth partition plate 6; the inlet of the first channel 7 is communicated with the perforated plate 2a in the area A, the inlet of the second channel 8 is communicated with the perforated plate 2B in the area B, and the inlet of the third channel 9 is communicated with the perforated plate 2C in the area C; the length of the first channel 7 is greater than that of the second channel 8, the length of the second channel 8 is greater than that of the third channel 9, and a first channel porous structure 7b, a second channel porous structure 8b and a third channel porous structure 9b are respectively filled in the first channel 7, the second channel 8 and the third channel 9. The low-frequency broadband acoustic metamaterial composite sound absorption device generates excellent low-frequency broadband sound absorption performance through multiple resonance and friction coupling tuning effects.
Referring to fig. 2, the microperforations 2d provided in the perforated plates 2a, 2B, and 2C in the zones a, B, and C have the same or different diameters.
If the microperforations 2d having the same diameter are provided in the perforated plates 2a, 2B, and 2C in the a block, the number of the microperforations 2d in the perforated plate 2a in the a block and the number of the microperforations 2d in the perforated plate 2C in the C block are each greater than the number of the microperforations 2d in the perforated plate 2B in the B block.
If the microperforations 2d having different diameters are provided in the perforated plates 2a, 2B, and 2C in the a block, the perforation rate of the microperforations 2d in the perforated plate 2a in the a block and the perforation rate of the microperforations 2d in the perforated plate 2B in the B block are both smaller than the perforation rate of the microperforations 2d in the perforated plate 2C in the C block.
Referring to fig. 3, 4 and 5, the first channel 7 is a straight channel and the cross-sectional dimension of the first channel 7 does not vary by more than 20% (i.e. it may be the same or may vary within 20%); the second channel 8 is a bending channel, the bending number of the bending channel is two, the size of the section of each section of the bending channel is not more than 20%, and the size of the section of each section of the bending channel is different and is not more than 50%; the third channel 9 is a bending channel, the bending number of the bending channel is three, the size of the cross section of each section of the bending channel is not more than 20%, and the size of the cross section of one section of the bending channel is different from that of the other two sections of the bending channel and is not more than 50%.
Referring to fig. 6 and 7, the cross-sectional shapes of the first channel 7, the second channel 8 and the third channel 9 are square or circular, and can be selected according to needs.
The cross-sectional shape of the basic cabin body 1 is square or round, and can be selected according to the needs, the basic cabin body 1 is only provided with an opening in a communication area with the micro-perforated plate 2, and the size of the opening is the same as the area of the micro-perforated plate 2.
Referring to fig. 3, the front section of the first channel 7 is filled with a first channel fluid 7a, the rear section of the first channel 7 is filled with a first channel porous structure 7b, and the first channel fluid 7a is respectively communicated with the zone a perforated plate 2a and the first channel porous structure 7 b.
Referring to fig. 4, the front section of the second channel 8 is filled with a second channel fluid 8a, the rear section of the second channel 8 is filled with a second channel porous structure 8b, or the rear section of the second channel 8 is filled with a second channel porous structure 8b and a second channel fluid 8a (i.e., a part of the second channel 8 rear section may be filled with a second channel porous structure 8b, and another part is filled with a second channel fluid 8 a).
Referring to fig. 5, the front section of the third channel 9 is filled with a third channel fluid 9a, the rear section of the third channel 9 is completely filled with a third channel porous structure 9b, or the rear section of the third channel 9 is filled with a third channel porous structure 9b and a third channel fluid 9a (i.e., one part of the rear section of the third channel 9 may be filled with the third channel porous structure 9b, and the other part is filled with the third channel fluid 9 a).
The embodiment also provides a preparation method of the low-frequency broadband acoustic metamaterial composite sound absorption device, which generally comprises the following steps: firstly, preparing each component of the low-frequency broadband acoustic metamaterial composite sound absorption device; then all the components are connected and assembled together, and the specific steps comprise:
step S1, preparing a micro-perforated plate 2, wherein the micro-perforated plate 2 comprises a metal micro-perforated plate and a nonmetal micro-perforated plate, and the typical micro-perforated plate comprises steel, iron, aluminum alloy, organic glass, plastic, a wood plate and a carbon fiber composite material;
step S2, preparing a first channel porous structure 7b, a second channel porous structure 8b and a third channel porous structure 9b, wherein the materials can be polyimide, melamine, polyurethane, foam metal, glass fiber, stainless steel fiber, slag wool and polyester wool;
step S3, integrally preparing the basic cabin 1 with the first partition board 3, the second partition board 4, the third partition board 5 and the fourth partition board 6, wherein the orientation relation satisfies: the area is enclosed to the basis cabin body 1, first baffle 3, second baffle 4 and forms first passageway 7, and the second passageway 8 is enclosed to the basis cabin body 1, the upside of first baffle 3, second baffle 4, the 5 upsides of third baffle and the 6 upsides of fourth baffle, and the third passageway 9 is enclosed to the basis cabin body 1, the 3 downside of first baffle, the 5 downside of third baffle and the 6 downside of fourth baffle.
Or the basic cabin body 1, the first partition plate 3, the second partition plate 4, the third partition plate 5 and the fourth partition plate 6 are separately prepared, the first partition plate 3 and the second partition plate 4 are installed and connected in the basic cabin body 1 to form a first channel 7, the basic cabin body 1, the upper side of the first partition plate 3, the upper side of the second partition plate 4, the upper side of the third partition plate 5 and the upper side of the fourth partition plate 6 enclose a second channel 8, and the basic cabin body 1, the lower side of the first partition plate 3, the lower side of the third partition plate 5 and the lower side of the fourth partition plate 6 enclose a third channel 9.
The basic cabin body 1, the first partition plate 3, the second partition plate 4, the third partition plate 5 and the fourth partition plate 6 can be made of metal materials or non-metal materials, and typically made of steel, iron, aluminum alloy, organic glass, PLA, plastic, rubber, wood plates, stone materials and carbon fiber composite materials.
Step S4, installing the first channel porous structure 7b in the first channel 7, installing the second channel porous structure 8b in the second channel 8, and installing the third channel porous structure 9b in the third channel 9;
and step S5, the micro-perforated plate 2 is communicated with the perforated plate 2a in the area A according to the inlet of the first channel 7, the inlet of the second channel 8 is communicated with the perforated plate 2B in the area B, and the inlet of the third channel 9 is arranged at the opening position on the basic cabin 1 according to the direction relation of the communication between the perforated plate 2C in the area C.
The invention will be further explained below with reference to a specific embodiment.
The basic cabin body 1, the first clapboard 3, the second clapboard 4, the third clapboard 5, the fourth clapboard 6 and the third channel porous structure 9B are integrally prepared by a 3D printing technology, the material can be PLA, the whole length is 120mm, the width is 60mm, the depth is 50mm, the wall thickness is 1mm, the shapes of the first channel 7, the second channel 8 and the third channel 9 are all square, the first channel 7 is a straight channel, the bending number of the second channel 8 is two, the bending number of the third channel 9 is three, the first channel fluid 7a, the second channel fluid 8a and the third channel fluid 9a are all air, the first channel porous structure 7B, the second channel porous structure 8B and the third channel porous structure 9B are all melamine, the microperforated panel 2 is made of aluminum alloy, the thickness is 0.4mm, a plurality of microperforations 2D with the diameter of 0.4mm are arranged on the perforated panel 2a in the A area, the perforated panel 2B in the B area and the perforated panel 2C in the C area, the perforation rate of the perforated plate 2C in zone C is 2 times that of the perforated plate 2B in zone B.
When the sound absorption experiment is carried out for testing, a double-sensor method is adopted in the impedance tube for testing, white noise sound waves are vertically incident from the surface of the micro-perforated plate, the test result refers to figure 8, wherein the ordinate represents the sound absorption coefficient and is a scalar, the abscissa represents the frequency, the unit is Hz, and it can be seen that: the sound absorption coefficient of all points in the frequency range of 150 Hz-1800 Hz is higher than 0.725, the average sound absorption coefficient reaches 0.906, and the high-efficiency absorption of low-frequency broadband is realized; the results show that: adopt the utility model discloses a compound sound absorbing device of low frequency broadband acoustics metamaterial all has excellent sound-absorbing capacity at very wide low frequency band, and application prospect is wide.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, various changes and modifications can be made by the owner within the scope of the appended claims, and the protection scope of the present invention should not be exceeded by the claims.
Claims (9)
1. The low-frequency broadband acoustic metamaterial composite sound absorption device is characterized by comprising a basic cabin body, a micro-perforated plate, a first partition plate, a second partition plate, a third partition plate, a fourth partition plate, a first channel, a second channel and a third channel, wherein the micro-perforated plate comprises an A-area perforated plate, a B-area perforated plate and a C-area perforated plate, and micro-perforations are arranged on the A-area perforated plate, the B-area perforated plate and the C-area perforated plate; the first partition plate, the second partition plate, the third partition plate and the fourth partition plate are arranged in the basic cabin body, the first channel is defined by the basic cabin body, the first partition plate and the second partition plate, the second channel is defined by the basic cabin body, the upper side of the first partition plate, the second partition plate, the upper side of the third partition plate and the fourth partition plate, and the third channel is defined by the basic cabin body, the lower side of the first partition plate, the lower side of the third partition plate and the fourth partition plate; the first channel inlet is communicated with the perforated plate in the area A, the second channel inlet is communicated with the perforated plate in the area B, and the third channel inlet is communicated with the perforated plate in the area C; the length of the first channel is greater than that of the second channel, the length of the second channel is greater than that of the third channel, and a first channel porous structure, a second channel porous structure and a third channel porous structure are respectively filled in the first channel, the second channel and the third channel.
2. The low-frequency broadband acoustic metamaterial composite sound absorbing device as claimed in claim 1, wherein if the micro-perforations with the same diameter are arranged on the perforated plates of the A area, the perforated plates of the B area and the perforated plates of the C area, the number of the micro-perforations on the perforated plates of the A area and the number of the micro-perforations on the perforated plates of the C area are both greater than the number of the micro-perforations on the perforated plates of the B area.
3. The low-frequency broadband acoustic metamaterial composite sound absorbing device as claimed in claim 1, wherein if micro-perforations with different diameters are provided on the block a perforated plate, the block B perforated plate and the block C perforated plate, the perforation rate of the micro-perforations on the block a perforated plate and the perforation rate of the micro-perforations on the block B perforated plate are both smaller than the perforation rate of the micro-perforations on the block C perforated plate.
4. The low-frequency broadband acoustic metamaterial composite sound absorbing device according to claim 1, wherein the first channel is a straight channel and the cross-sectional dimension of the first channel does not vary by more than 20%; the second channel is a bent channel, the number of bends of the bent channel is two, the size of the cross section of each section of the bent channel is not more than 20%, and the size of the cross section of each section of the bent channel is different and is not more than 50%; the third channel is a bent channel, the number of bends of the bent channel is three, the size of the cross section of each section of the bent channel is not more than 20%, and the size of the cross section of one section of the bent channel is different from that of the other two sections of the bent channel and is not more than 50%.
5. The low frequency broadband acoustic metamaterial composite sound absorbing device of claim 1, wherein the cross-sectional shape of the first, second, and third channels is square or circular.
6. The low-frequency broadband acoustic metamaterial composite sound absorbing device as claimed in claim 1, wherein the cross-sectional shape of the basic hull is square or circular, the basic hull is provided with an opening in a communication area with the micro-perforated plate, and the size of the opening is the same as the area of the micro-perforated plate.
7. The low-frequency broadband acoustic metamaterial composite sound absorbing device according to claim 1, wherein the front section of the first channel is filled with a first channel fluid, the rear section of the first channel is filled with a first channel porous structure, and the first channel fluid is respectively communicated with the zone A perforated plate and the first channel porous structure.
8. The low-frequency broadband acoustic metamaterial composite sound absorbing device according to claim 1, wherein the front section of the second channel is filled with a second channel fluid, and the rear section of the second channel is completely filled with a second channel porous structure or the rear section of the second channel is filled with the second channel porous structure and the second channel fluid; and the front section of the third channel is filled with a third channel fluid, and the rear section of the third channel is completely filled with a third channel porous structure or is filled with the third channel porous structure and the third channel fluid.
9. The low-frequency broadband acoustic metamaterial composite sound absorbing device according to claim 1, wherein the micro-perforated plate comprises a metal micro-perforated plate and a non-metal micro-perforated plate, the base cabin, the first partition plate, the second partition plate, the third partition plate and the fourth partition plate are made of metal materials or non-metal materials, and the first channel porous structure, the second channel porous structure and the third channel porous structure are made of polyimide, melamine, polyurethane, foamed metal, glass fiber, stainless steel fiber, slag wool or polyester wool.
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| CN113393826A (en) * | 2021-06-10 | 2021-09-14 | 中国人民解放军国防科技大学 | Low-frequency broadband acoustic metamaterial composite sound absorption structure and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113393826A (en) * | 2021-06-10 | 2021-09-14 | 中国人民解放军国防科技大学 | Low-frequency broadband acoustic metamaterial composite sound absorption structure and preparation method thereof |
| CN113393826B (en) * | 2021-06-10 | 2024-01-26 | 中国人民解放军国防科技大学 | Low-frequency broadband acoustic metamaterial composite sound absorption structure and preparation method |
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