Acoustic metamaterial composite structure soundproof cover

Abstract

This invention discloses an acoustic metamaterial composite structure soundproof enclosure, comprising a first thin-film acoustic metamaterial plate, a second thin-film acoustic metamaterial plate, and a third thin-film acoustic metamaterial plate. The first thin-film acoustic metamaterial plate has a first acoustic impedance; the second thin-film acoustic metamaterial plate is located outside the first thin-film acoustic metamaterial plate and has a second acoustic impedance, which is greater than the first acoustic impedance; the third thin-film acoustic metamaterial plate is located outside the second thin-film acoustic metamaterial plate and has a third acoustic impedance. A first porous plate is located between the first and second thin-film acoustic metamaterial plates, and a second porous plate is located between the second and third thin-film acoustic metamaterial plates. According to this invention, the acoustic metamaterial composite structure soundproof enclosure can achieve low-frequency broadband sound insulation by utilizing the acoustic impedance design between multiple acoustic metamaterials.

Description

Technical Field

[0001] This invention relates to the field of noise reduction applications, specifically to an acoustic metamaterial composite structure soundproof cover. Background Technology

[0002] As a commonly used noise control method, a soundproof enclosure is a dome-shaped structure that encloses a sound source within a small space to reduce the noise radiated from the source to the surrounding environment. The acoustic performance of a soundproof enclosure is generally evaluated using its insertion loss, i.e., the difference in radiated sound power level before and after the enclosure's application. Since soundproof enclosures are typically closed cavity structures, they not only suffer from cavity resonance, but the wall panel structures themselves also possess complex acoustic vibration characteristics. Therefore, the acoustic performance of a soundproof enclosure is significantly affected by parameters such as sound source distribution, cavity size, and wall panel composition. Among these, sound source distribution is mainly determined by the properties of the sound source itself, while cavity size is limited by the space where the soundproof enclosure is applied. Therefore, the wall panel composition becomes the only key parameter that can be designed to improve the acoustic performance of the soundproof enclosure.

[0003] Traditional soundproof enclosure panels typically consist of porous materials composed of uniform panels, perforated panels, and interlayer fillers, offering good mid-to-high frequency (>500Hz) sound insulation performance, but often performing poorly in low-frequency sound insulation. To improve the low-frequency sound insulation capabilities of materials, the concept of acoustic metamaterials has been proposed. Acoustic metamaterials are artificially designed and manufactured composite structures. Due to their periodic structure and designable resonant characteristics, these materials possess unique properties not found in naturally occurring materials, such as negative equivalent density and negative equivalent Young's modulus. These special properties make acoustic metamaterials promising for applications in low-frequency sound insulation, sound absorption, and acoustic camouflage design.

[0004] However, due to the limitations of the working mechanism of acoustic metamaterials, their operating frequency band is relatively narrow. Although multiple acoustic metamaterials with different operating frequencies can be stacked together, it is still impossible to effectively compensate for the sound insulation trough caused by the phenomenon of total transmission (for example, sound wave energy is incident on one side of the acoustic metamaterial and is transmitted to the other side through the acoustic metamaterial, that is, the acoustic metamaterial has no isolation or absorption effect on the sound wave energy). (A trough appears on the sound insulation curve, indicating that the sound insulation ability is very poor.) In addition, the surface density of the overall material after stacking is very large, which makes it difficult to meet the needs of practical engineering applications.

[0005] Therefore, an acoustic metamaterial composite structure soundproof enclosure is needed to at least partially solve the above problems. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] To at least partially solve the above-mentioned technical problems, the present invention provides an acoustic metamaterial composite structure soundproof enclosure, characterized in that it comprises:

[0008] A first thin-film acoustic metamaterial plate, wherein the first thin-film acoustic metamaterial plate has a first acoustic impedance;

[0009] A second thin-film acoustic metamaterial plate is located outside the first thin-film acoustic metamaterial plate, and the second thin-film acoustic metamaterial plate has a second acoustic impedance greater than the first acoustic impedance; and

[0010] A third thin-film acoustic metamaterial plate is located outside the second thin-film acoustic metamaterial plate, and the third thin-film acoustic metamaterial plate has a third acoustic impedance.

[0011] The first thin-film acoustic metamaterial plate and the second thin-film acoustic metamaterial plate are connected by a first porous plate, and the second thin-film acoustic metamaterial plate and the third thin-film acoustic metamaterial plate are connected by a second porous plate.

[0012] Optionally, the first acoustic impedance is equal to the characteristic impedance of air.

[0013] Optionally, the third acoustic impedance is greater than the second acoustic impedance.

[0014] Optionally, at least one of the first thin-film acoustic metamaterial plate, the second thin-film acoustic metamaterial plate, and the third thin-film acoustic metamaterial plate includes:

[0015] A framework having multiple crystal lattices;

[0016] A thin film, the thin film being connected to the frame; and

[0017] Mass blocks, which are located in the lattice and connected to the thin film.

[0018] Optionally, the acoustic metamaterial composite structure soundproof enclosure includes:

[0019] A first support member extends through a hole in the first porous plate and is supported between the first thin-film acoustic metamaterial plate and the second thin-film acoustic metamaterial plate; and

[0020] The second support extends through the holes of the second porous plate and is supported between the second thin-film acoustic metamaterial plate and the third thin-film acoustic metamaterial plate.

[0021] Optionally, the projection of the first support member onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate at least partially coincides with the projection of the second support member onto the same plane.

[0022] Optionally, the projection of the first support member onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate completely coincides with the projection of the second support member onto the same plane; or

[0023] The projection of the first support member onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate does not coincide with the projection of the second support member onto the same plane.

[0024] Optionally, the first thin-film acoustic metamaterial plate is parallel to the third thin-film acoustic metamaterial plate.

[0025] Optionally, at least one of the first thin-film acoustic metamaterial plate and the third thin-film acoustic metamaterial plate is inclined relative to the second thin-film acoustic metamaterial plate.

[0026] The acoustic metamaterial composite structure soundproof cover of the present invention can achieve low-frequency broadband sound insulation effect by utilizing the acoustic impedance design between multiple layers of acoustic metamaterials.

[0027] Compared with the prior art, the acoustic metamaterial composite structure soundproof cover provided by the present invention has the following beneficial effects:

[0028] 1) The wall panel of the acoustic metamaterial composite structure soundproof cover in this invention is composed of multi-layer thin-film acoustic metamaterial plates and porous materials filling the interlayer, which has the characteristics of lightweight structure and is suitable for application scenarios with strict requirements on installation size and additional weight.

[0029] 2) Based on the noise characteristic frequency of the sound source inside the soundproof enclosure, the acoustic impedance of each layer of thin-film acoustic metamaterial plate is arranged in order of increasing from the inside to the outside, thereby generating a synergistic effect of sound wave absorption and isolation, and finally achieving low-frequency broadband sound insulation characteristics.

[0030] 3) The acoustic metamaterial composite structure soundproof cover in this invention has adjustable operating frequency band and can be flexibly designed for different internal sound source excitation frequencies to achieve efficient noise reduction effect. Attached Figure Description

[0031] To make the advantages of the invention more readily apparent, the invention briefly described above will be described in more detail with reference to the specific embodiments shown in the accompanying drawings. It will be understood that these drawings depict only typical embodiments of the invention and should not be considered as limiting its scope of protection. The invention is described and explained with additional features and details through the drawings.

[0032] Figure 1 This is a three-dimensional schematic diagram of the acoustic metamaterial composite structure soundproof cover of the present invention;

[0033] Figure 2 For along Figure 1 A partial schematic diagram of the cross-section intercepted by the centerline AA;

[0034] Figure 3 This is a schematic diagram of the thin-film acoustic metamaterial plate structure used in the wall panel of the acoustic metamaterial composite structure soundproof cover of the present invention.

[0035] Figure 4 This is a schematic diagram showing the acoustic impedance relationship of each layer of thin-film acoustic metamaterial plate used in the wall panel of the acoustic metamaterial composite structure soundproof cover of the present invention.

[0036] Figure 5A This is a schematic diagram of the structure of each layer of thin-film acoustic metamaterial plate in the wall panel of the acoustic metamaterial composite structure soundproof cover according to the first embodiment of the present invention.

[0037] Figure 5B This is a schematic diagram of the structure of each layer of thin-film acoustic metamaterial plate in the wall panel of the acoustic metamaterial composite structure soundproof cover according to the second embodiment of the present invention.

[0038] Figure 5C This is a schematic diagram of the structure of each layer of thin-film acoustic metamaterial plate in the wall panel of the acoustic metamaterial composite structure soundproof cover according to the third embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram of the insertion loss test of the acoustic metamaterial composite structure soundproof enclosure of the present invention; and

[0040] Figure 7 The results are the insertion loss test results of the acoustic metamaterial composite structure soundproof cover of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1: Acoustic metamaterial composite structure soundproof enclosure

[0043] 11: First Thin-Film Acoustic Metamaterial Panel

[0044] 12: First perforated plate

[0045] 13: Second thin-film acoustic metamaterial plate

[0046] 14: Second perforated plate

[0047] 15: Third Thin-Film Acoustic Metamaterial Panel

[0048] 16a: First support member

[0049] 16b: Second support member

[0050] 111: Framework

[0051] 112: Film

[0052] 113: Mass Block

[0053] A1: Semi-anechoic chamber

[0054] A2: Microphone

[0055] A3: Sound source Detailed Implementation

[0056] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0057] To fully understand the present invention, a detailed description will be set forth in the following description. It is obvious that the implementation of embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. Preferred embodiments of the present invention are described in detail below; however, in addition to these detailed descriptions, the present invention may have other embodiments.

[0058] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0059] The ordinal numbers such as "first" and "second" used in this invention are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term "first component" does not imply the existence of "second component," and the term "second component" does not imply the existence of "first component."

[0060] It should be noted that the terms “up,” “down,” “front,” “back,” “left,” “right,” “inner,” “outer,” and similar expressions used in this article are for illustrative purposes only and are not intended to be restrictive.

[0061] Exemplary embodiments according to the present invention will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the invention is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0062] like Figure 1 and Figure 2 As shown, this patent discloses an acoustic metamaterial composite structure soundproof enclosure 1. The acoustic metamaterial composite structure soundproof enclosure 1 includes multiple wall panels. The wall panels may include multilayer thin-film acoustic metamaterial panels and porous plates between the layers. Figure 1 and Figure 2 In the illustrated embodiment, the acoustic metamaterial composite structure soundproof enclosure 1 comprises a first thin-film acoustic metamaterial plate 11, a second thin-film acoustic metamaterial plate 13, and a third thin-film acoustic metamaterial plate 15. A first porous plate 12 is provided between the first thin-film acoustic metamaterial plate 11 and the second thin-film acoustic metamaterial plate 13, and a second porous plate 14 is provided between the second thin-film acoustic metamaterial plate 13 and the third thin-film acoustic metamaterial plate 15. The plates of each layer can be directly bonded together or supported by a support member.

[0063] Furthermore, the first thin-film acoustic metamaterial plate 11 has a first acoustic impedance. The second thin-film acoustic metamaterial plate 13 has a second acoustic impedance, which is greater than the first acoustic impedance. The third thin-film acoustic metamaterial plate 15 has a third acoustic impedance.

[0064] The acoustic metamaterial composite structure soundproof cover 1 of the present invention can achieve low-frequency broadband sound insulation effect by utilizing the acoustic impedance design between multiple layers of acoustic metamaterials.

[0065] Compared with the prior art, the acoustic metamaterial composite structure soundproof cover 1 provided by the present invention has the following beneficial effects:

[0066] 1) The wall panel of the acoustic metamaterial composite structure soundproof cover 1 in this invention is composed of multi-layer thin film acoustic metamaterial plates and porous materials filling the interlayer, which has the characteristics of lightweight structure and is suitable for application scenarios with strict requirements on installation size and additional weight.

[0067] 2) Regarding the sound source A3 inside the soundproof enclosure ( Figure 6The noise characteristic frequency of the sound wave is determined by arranging the acoustic impedance of each layer of thin-film acoustic metamaterial plate in an order of increasing from the inside out, thereby generating a synergistic effect of sound wave absorption and isolation, and ultimately achieving low-frequency broadband sound insulation characteristics.

[0068] 3) The acoustic metamaterial composite structure soundproof cover 1 in this invention has adjustable operating frequency band and can be flexibly designed for different excitation frequencies of internal sound source A3 to achieve efficient noise reduction effect.

[0069] Preferably, in order to generate a synergistic effect of sound wave absorption (removing or dissipating the energy of the incident sound wave) and isolation (blocking or reflecting the energy of the incident sound wave), and ultimately achieve low-frequency broadband sound insulation characteristics, the acoustic impedance of each layer of thin-film acoustic metamaterial plate in the wall panel of the acoustic metamaterial composite structure soundproof cover 1 proposed in this invention is arranged in order of increasing from the inside to the outside.

[0070] Furthermore, the physical effects of absorption and isolation are contradictory for ordinary materials. This means that for a material to have strong absorption capacity, sound waves need to enter the interior of the material (the acoustic impedance of the material must be equal to the acoustic impedance of air). Through the frictional and viscous effects inside the material, the kinetic energy carried by the sound waves is converted into heat energy, ultimately achieving loss absorption. On the other hand, for a material to have strong isolation capacity, sound waves cannot enter the interior of the material (the acoustic impedance of the material must be much greater than the acoustic impedance of air), but are blocked in front of it as much as possible.

[0071] The "synergistic effect of absorption and isolation" described in this invention refers to the gradual arrangement of acoustic impedances of multi-layer acoustic metamaterial plates. The acoustic impedance of the first layer of acoustic metamaterial plates is equal to that of air, while the acoustic impedance of the last layer of acoustic metamaterial plates is much greater than that of air, so that the entire system can both absorb and isolate incident sound waves.

[0072] like Figure 4As shown, taking the first thin-film acoustic metamaterial plate 11, the second thin-film acoustic metamaterial plate 13, and the third thin-film acoustic metamaterial plate 15 as examples, the relationship between their normalized acoustic impedance (i.e., divided by the characteristic impedance of air) is illustrated. Specifically, the acoustic impedance of the innermost first thin-film acoustic metamaterial plate 11 is equal to the characteristic impedance of air, thereby achieving impedance matching with the air medium, making it easier for sound waves to pass through the first thin-film acoustic metamaterial plate 11 and enter the first porous plate 12. The acoustic impedance of the middle layer second thin-film acoustic metamaterial plate 13 is slightly greater than the characteristic impedance of air (e.g., 1.5-10 times the characteristic impedance of air). The acoustic impedance of the outermost third thin-film acoustic metamaterial plate 15 can be much greater than the characteristic impedance of air (e.g., 10-100 times the characteristic impedance of air), ultimately resulting in a complete impedance mismatch with the air medium, causing sound waves to be completely reflected and unable to pass through the third thin-film acoustic metamaterial plate 15. This acoustic impedance arrangement allows all sound waves to be concentrated inside the wall panel structure, and then completely absorbed by the first porous plate 12 and the second porous plate 14.

[0073] like Figure 3 As shown, optionally, at least one of the first thin-film acoustic metamaterial plate 11, the second thin-film acoustic metamaterial plate 13, and the third thin-film acoustic metamaterial plate 15 includes a crystal lattice framework 111, a thin film 112, and a mass block 113. The thin film 112 is connected to the crystal lattice framework 111. The mass blocks 113 are located in the crystal lattice and connected to the thin film 112.

[0074] Taking the first thin-film acoustic metamaterial plate 11 as an example, it includes a frame 111 in the form of a periodic lattice. A thin film 112 is disposed on one side of the frame 111, and the thin film 112 is divided into periodic lattices by the frame 111. A mass block 113 is disposed at the center of each lattice. The frame 111 provides boundary support, and the thin film 112 and the mass block 113 provide elasticity and inertia, respectively, thus forming a "spring-mass" resonant system. This resonant system has a series of resonant and anti-resonant states. When in the resonant state, the acoustic impedance of each lattice is at a minimum value, while when in the anti-resonant state, the acoustic impedance of each lattice is at a maximum value. By designing the geometry of each lattice, the material and thickness of the thin plate 2, and the material and shape of the mass block 113, the occurrence frequencies of the lattice resonant and anti-resonant states can be realized, thereby effectively changing the magnitude of the acoustic impedance at the frequency of interest.

[0075] Figures 5A-5C This is a schematic diagram of the structure (installation relationship) of each layer of thin-film acoustic metamaterial panels in the wall panel of the acoustic metamaterial composite structure soundproof cover 1 of the present invention. In this embodiment, a support member is used to support the thin-film acoustic metamaterial panels of different layers.

[0076] Specifically, the support includes a first support 16a and a second support 16b. The first support 16a extends through a hole in the first porous plate 12 and is supported between the first thin-film acoustic metamaterial plate 11 and the second thin-film acoustic metamaterial plate 13. The second support 16b extends through a hole in the second porous plate 14 and is supported between the second thin-film acoustic metamaterial plate 13 and the third thin-film acoustic metamaterial plate 15.

[0077] exist Figure 5A In this configuration, the first thin-film acoustic metamaterial plate 11, the second thin-film acoustic metamaterial plate 13, and the third thin-film acoustic metamaterial plate 15 are substantially parallel. Support members are only provided at the top and bottom ends. Alternatively, the projection of the first support member 16a onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate 11 may completely coincide with the projection of the second support member 16b onto the same plane.

[0078] exist Figure 5B In addition to supporting the upper and lower ends, the support member also has a support in the middle part, thus having better support rigidity. Furthermore, the projection of the first support member 16a on the plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate 11 does not coincide with the projection of the second support member 16b on the plane.

[0079] Of course, in embodiments not shown, the projection of the first support 16a onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate 11 at least partially coincides with the projection of the second support 16b onto the plane.

[0080] Figure 5C Optionally, at least one of the first thin-film acoustic metamaterial plate 11 and the third thin-film acoustic metamaterial plate 15 is inclined relative to the second thin-film acoustic metamaterial plate 13. The first support member 16a and the second support member 16c provide inclined support for the second thin-film acoustic metamaterial plate 13 placed in the middle, which can improve the isolation performance against multi-directional incident sound sources. Furthermore, the first support member 16a and the second support member 16c can be disposed at the ends of the inclined second thin-film acoustic metamaterial plate 13 near the ends of the first thin-film acoustic metamaterial plate 11 and the third thin-film acoustic metamaterial plate 15.

[0081] like Figure 6As shown, the insertion loss of the soundproof enclosure was tested and verified in a semi-anechoic chamber A1. A2 in the figure represents the microphone. For comparison, an insertion loss test was also conducted on a conventional soundproof enclosure. The conventional soundproof enclosure consists of a frame 111 and wall panels. The frame 111 is made of square steel, and the wall panels are made of 2mm steel plate. The wall panels are bolted to the frame 111. Both soundproof enclosures have an outer dimension of 1000mm × 1000mm × 1000mm. The radiated sound power of the soundproof enclosure was tested using the 9-point method shown in Figure C.7 of Appendix C of GB / T 3767-2016. The test data were compared and analyzed using the 1 / 3 frequency band sound pressure level under A-weighting. The insertion loss of the soundproof enclosure was calculated using the following formula:

[0082] IL = SWL wo barrier -SWL w barrier

[0083] In the formula, SWL wo barrier SWL represents the radiated sound power level without a soundproof enclosure. w barrier This indicates the radiated sound power level when a soundproof enclosure is placed.

[0084] The comparison of test results can be found in the following figures. Figure 7 As shown in the figure, the sound insulation performance B2 of the acoustic metamaterial composite structure soundproof cover 1 in the entire frequency range of interest is better than that of the traditional soundproof cover B1. In particular, the average noise reduction is improved by more than 8dB in the 50Hz to 1000Hz frequency range, which shows that the acoustic metamaterial composite structure soundproof cover 1 has excellent low-frequency broadband sound insulation performance.

[0085] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

[0086] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the invention. Terms such as “component” as used herein may refer to a single part or a combination of multiple parts. Terms such as “installation” or “installation” as used herein may refer to a component being directly attached to another component or a component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0087] The present invention has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the present invention to the described embodiments. Those skilled in the art will understand that many variations and modifications can be made based on the teachings of the present invention, and all such variations and modifications fall within the scope of protection claimed by the present invention.

Claims

1. A soundproof enclosure with an acoustic metamaterial composite structure, characterized in that, include: A first thin-film acoustic metamaterial plate, wherein the first thin-film acoustic metamaterial plate has a first acoustic impedance; A second thin-film acoustic metamaterial plate is located outside the first thin-film acoustic metamaterial plate, and the second thin-film acoustic metamaterial plate has a second acoustic impedance, which is greater than the first acoustic impedance, and the first acoustic impedance is equal to the characteristic impedance of air. as well as A third thin-film acoustic metamaterial plate is located outside the second thin-film acoustic metamaterial plate, and the third thin-film acoustic metamaterial plate has a third acoustic impedance, which is greater than the second acoustic impedance and is 10-100 times the characteristic impedance of air. The first thin-film acoustic metamaterial plate and the second thin-film acoustic metamaterial plate are connected by a first porous plate, and the second thin-film acoustic metamaterial plate and the third thin-film acoustic metamaterial plate are connected by a second porous plate.

2. The acoustic metamaterial composite structure soundproof cover according to claim 1, characterized in that, At least one of the first thin-film acoustic metamaterial plate, the second thin-film acoustic metamaterial plate, and the third thin-film acoustic metamaterial plate includes: A framework having multiple crystal lattices; A thin film, the thin film being connected to the frame; and Mass blocks, which are located in the lattice and connected to the thin film.

3. The acoustic metamaterial composite structure soundproof cover according to claim 1, characterized in that, The acoustic metamaterial composite structure soundproof cover includes: A first support member extends through a hole in the first porous plate and is supported between the first thin-film acoustic metamaterial plate and the second thin-film acoustic metamaterial plate; and The second support extends through the holes of the second porous plate and is supported between the second thin-film acoustic metamaterial plate and the third thin-film acoustic metamaterial plate.

4. The acoustic metamaterial composite structure soundproof cover according to claim 3, characterized in that, The projection of the first support member onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate at least partially coincides with the projection of the second support member onto the same plane.

5. The acoustic metamaterial composite structure soundproof cover according to claim 3, characterized in that, The projection of the first support member onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate completely coincides with the projection of the second support member onto the same plane; or The projection of the first support member onto a plane perpendicular to the thickness direction of the first thin-film acoustic metamaterial plate does not coincide with the projection of the second support member onto the same plane.

6. The acoustic metamaterial composite structure soundproof cover according to claim 1, characterized in that, The first thin-film acoustic metamaterial plate is parallel to the third thin-film acoustic metamaterial plate.

7. The acoustic metamaterial composite structure soundproof cover according to claim 1, characterized in that, At least one of the first thin-film acoustic metamaterial plate and the third thin-film acoustic metamaterial plate is inclined relative to the second thin-film acoustic metamaterial plate.

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