Stepped multi-order broadband metal film acoustic metamaterial module and sound insulation structure

Abstract

The invention discloses a stepped multi-order broadband metal film acoustic metamaterial module and a sound insulation structure, and belongs to the technical field of acoustic metamaterials, the stepped multi-order broadband metal film acoustic metamaterial module comprises a film, a central mass block arranged at the center of the film and m mass rings, the central mass block is arranged at the center, m is a natural number greater than 1, and m is a natural number greater than 1. The m mass rings are sequentially arranged from the center to the outside, the mass rings are arranged on the periphery of the center mass block in a surrounding mode and are arranged to be annular in a closed mode, and the heights of the mass rings are gradually increased; the thin film is made of metal or metal alloy, and a multi-order resonance structure is formed by arranging the mass rings with the heights increased layer by layer on the two sides of the thin film, so that all-order resonance modes can generate a resonance effect in different frequency ranges, and the sound insulation frequency band is effectively widened.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic metamaterials, and in particular to a stepped multi-order broadband metal film acoustic metamaterial module and a sound insulation structure. Background Art

[0002] In recent years, acoustic metamaterials have become a hot topic of research due to their excellent low-frequency sound insulation performance. However, their use is limited due to their narrow sound insulation band, large-size attenuation, and weather resistance of non-metallic films. The resonance peak of local resonance-type thin-film acoustic metamaterials is narrow. There are currently two ways. One is to superimpose different resonance peaks in thickness, which makes the overall thickness thicker and affects the application; the second is to use a narrow and long unit cell structure and set multiple mass blocks in the length direction to obtain multiple anti-resonance modes to achieve low-frequency sound insulation. However, due to the long length direction, a large area will fail after cutting, so there are certain problems in engineering applications. In order to meet these challenges, existing technologies usually use two main methods to improve the sound insulation performance of acoustic metamaterials. One is to superimpose mass blocks with different resonance frequencies in the material thickness direction. Although this method can achieve broadband sound insulation, it will cause a significant increase in the overall thickness, limiting its use in application scenarios with limited space. Another method is the prior art Chinese patent publication number CN113409753B, a multilayer thin-film acoustic metamaterial structure and its design method. The metamaterial structure includes a plurality of superimposed thin-film acoustic metamaterial units with different structural parameters, each of which is divided by a hard frame to form a wide-band low-frequency sound insulation structure with multiple sound insulation peaks. The method includes the following steps: calculating the sound insulation peak frequency of the metamaterial unit; constructing the acoustic metamaterial structure according to the sound insulation peak frequency in a form of equal spacing, peak-valley complementation, and customization according to the noise source, and by adopting a narrow and long unit cell structure and arranging a plurality of mass blocks in the length direction to generate a plurality of anti-resonance modes, thereby widening the sound insulation frequency band.

[0003] However, the above designs all significantly increase the thickness or width of the structure, which limits the usage scenarios and also affects the sound insulation effect. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical problems and provide a stepped multi-order broadband metal film acoustic metamaterial module and a sound insulation structure.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A stepped multi-order broadband metal film acoustic metamaterial module comprises a film, a central mass block arranged at the center of the film, and m mass rings, wherein the central mass block is arranged at the center, m is a natural number greater than 1, and the m mass rings are arranged in sequence from the center to the outside, the mass rings are arranged around the periphery of the central mass block and are closed in a ring shape, and the heights of the mass rings gradually increase; the material of the film is metal or metal alloy.

[0007] The preferred technical solution of the present invention is that the area surrounded by the nth mass ring forms an nth-order acoustic metamaterial, where n is any natural number greater than or equal to 1 and less than or equal to m; the height of the central mass block is h mass , mass is M mass ; The mass of the nth mass ring is M frame,n ; The stiffness of the film is K; The natural frequency of the nth order acoustic metamaterial is f n , where the calculation formula for the natural frequency of the first-order acoustic metamaterial is The calculation formula for the natural frequency of the nth-order acoustic metamaterial is: Where Mn is the equivalent mass of the film at the center corresponding to the nth order, M e,n-1 is the equivalent mass of the n-1th order acoustic metamaterial.

[0008] A preferred technical solution of the present invention is that the thickness of the film is less than or equal to 0.2 mm.

[0009] The preferred technical solution of the present invention is that the thickness d of the film is calculated according to the stiffness K of the film, which conforms to the following formula: Where E is Young's modulus and μ is Poisson's ratio.

[0010] The height of the nth mass ring (3) is h n， The height difference between adjacent mass rings (3) is Δh, ω=2πf n , where C 0 is the speed of sound in air, ω is the angular frequency, when the film is square, a is the side length; when the film is circular, a is the diameter; when the film is other shapes, a is the equivalent diameter of the film, at this time the equivalent diameter a = 4A / L, A is the area of ​​the film, and L is the circumference of the film.

[0011] A preferred technical solution of the present invention is that three mass rings are provided.

[0012] The preferred technical solution of the present invention is that the material of the mass ring is steel or aluminum alloy or carbon fiber or engineering ABS plastic; the material of the central mass block is stainless steel; and the material of the film is stainless steel or aluminum alloy.

[0013] A preferred technical solution of the present invention is that the mass rings are located on both sides of the film and are symmetrically arranged.

[0014] A preferred technical solution of the present invention is that the shape formed by the mass ring is a square, a circle, a regular hexagon or a triangle.

[0015] A preferred technical solution of the present invention is that the mass ring is centrally symmetrical with respect to the central mass block along the plane where the film is located.

[0016] A stepped multi-order broadband metal film acoustic metamaterial module sound insulation structure is composed of any one of the stepped multi-order broadband metal film acoustic metamaterial module arrays described above.

[0017] The beneficial effects of the present invention are:

[0018] (1) By setting mass rings with increasing heights on both sides of the film, a multi-order resonance structure is formed, so that each order of resonance mode can produce a resonance effect within a different frequency range, thereby effectively broadening the sound insulation band.

[0019] (2) The coupling effect between the mass rings at different heights and positions and the film achieves more effective energy absorption and transfer, improving the overall sound insulation performance.

[0020] (3) The use of metal film as the substrate not only enhances the mechanical strength and stability of the material, but also greatly improves its weather resistance and service life, allowing it to maintain good performance in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated into the specification and constitute a part of the specification, illustrate embodiments of the present invention and are used together with the description to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, but not all embodiments. For those of ordinary skill in the art, other drawings can be obtained from these drawings without paying creative work.

[0022] Figure 1 It is a schematic top view of the overall structure of a stepped multi-stage broadband metal film acoustic metamaterial provided in a specific embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the bottom of the overall structure of the stepped multi-stage broadband metal film acoustic metamaterial provided in a specific embodiment of the present invention;

[0024] Figure 3 It is a front view of the overall structure of the stepped multi-stage broadband metal film acoustic metamaterial provided in a specific embodiment of the present invention;

[0025] Figure 4 yes Figure 3 Cross-sectional view of the middle BB;

[0026] Figure 5 1 is a schematic diagram of the overall structure of Example 2 of a multi-order broadband metal film acoustic metamaterial sound insulation module provided in a specific embodiment of the present invention;

[0027] Figure 6 1 is a schematic diagram of the overall structure of Example 3 of a multi-order broadband metal film acoustic metamaterial sound insulation module provided in a specific embodiment of the present invention;

[0028] Figure 7 It is a schematic diagram of the overall structure of Example 4 of the multi-order broadband metal film acoustic metamaterial sound insulation module provided in a specific embodiment of the present invention.

[0029] In the figure:

[0030] 1. Thin film; 2. Central mass block; 3. Mass ring; 31. First mass ring; 32. Second mass ring; 33. Third mass ring; 34. Fourth mass ring; 35. Fifth mass ring. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0032] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0033] Example 1

[0034] The present invention provides a stepped multi-stage broadband metal film acoustic metamaterial module, comprising a film 1, a central mass block 2 and m mass rings 3 arranged on the film 1, m being a natural number greater than 1, the film 1 being made of metal or metal alloy, the central mass block 2 being arranged in the middle of the film 1, the mass ring 3 surrounding the central mass block 2 and being closed in a ring shape; the m mass rings 3 are arranged in sequence from the center to the outside, and the heights of the m mass rings 3 gradually increase. The film 1 is made of metal or metal alloy, wherein the first mass ring 3 (such as Figure 35) forms a first-order acoustic metamaterial inside, and the first mass ring 3 also serves as a frame of the first-order acoustic metamaterial. The area surrounded by the nth mass ring 3 forms an nth-order acoustic metamaterial, and the nth mass ring also serves as a frame of the nth-order acoustic metamaterial. It effectively covers a wider frequency range and has excellent sound insulation performance. At the same time, due to the annular arrangement of the mass ring 3, several frame-like effects from the inside to the outside can be formed on the sound insulation module, making the structure more stable.

[0035] like Figure 1-3 As shown, in this embodiment, three mass rings 3 are provided, that is, m=3, then n=1 or 2 or 3.

[0036] like Figure 3 As shown in the figure, a central mass block 2 is fixed on the film 11 inside the first mass ring 31 to form a first-order acoustic metamaterial;

[0037] The area surrounded by the second mass ring 32 forms a second-order acoustic metamaterial. Here, the area surrounded by the second mass ring 32 is composed of the second mass ring 32, the first mass ring 31, the central mass block 2 and the film 1 in the corresponding surrounding area.

[0038] The area surrounded by the third mass ring 33 forms a third-order acoustic metamaterial. Here, the area surrounded by the third mass ring 33 is composed of the third mass ring 33, the second mass ring 32, the first mass ring 31, the central mass block 2 and the film 1 in the corresponding surrounding area.

[0039] The mass ring 3 is centrally symmetrical with respect to the central mass block 2 along the plane where the membrane 1 is located, which enhances the structural stability and makes the interaction force between the mass ring 3 and the central mass block 2 more balanced, which helps to enhance the stability of the entire structure, optimize the vibration mode, and improve the sound insulation effect. It can more effectively suppress the symmetrical vibration mode of the membrane, thereby increasing the generation of asymmetric vibration forms, and helps to contribute more structural resonances to the sound absorption peak, thereby improving the sound insulation effect in the low frequency band.

[0040] The central mass block 2 is made of stainless steel. The central mass block 2 is mainly used to adjust the resonance frequency and enhance the sound insulation effect. The central mass block 2 can be fixed to the middle of one side of the film 1 by welding or bonding. The stainless steel central mass block 2 is fixed to the film 1 using laser welding technology to ensure a firm and reliable connection.

[0041] The film 1 is a metal or metal alloy, commonly used are stainless steel, aluminum alloy, etc., and its thickness is usually less than or equal to 0.2 mm. The selection of the film 1 needs to comprehensively consider its mechanical properties and weather resistance. It not only has good toughness, but also has excellent corrosion resistance and is suitable for various environments.

[0042] Definition: The height of the central mass block 2 is its height h mass , mass is M mass , the height of the nth mass ring 3 is h n , mass is M frame,n , where the height of the mass ring 3 is the distance from the top to the film.

[0043] The distances between n adjacent mass rings 3 arranged in sequence from the center to the outside are set according to the equivalent diameters between the films 1 of each order, ensuring the synergy between the various metamaterial structures and improving the overall sound insulation effect. It is necessary to ensure that the vibration of each order is not restricted, and the modal vibration type between each order will not affect the films 1 in other orders. The sound insulation frequency bands between the orders are specially designed in a stepped manner, so that multiple orders complement each other to form broadband sound insulation.

[0044] The height of the mass ring 3 of the first-order acoustic metamaterial is h 1 , the height of the mass ring 3 of the second-order acoustic metamaterial is h 2 ,like Figure 4 As shown, along the direction of the outermost mass ring are h 2 、h 3 ...h n , and h mass <h 1 <h 2 <… <h n The height of the central mass block 2 is made lower than the height of the innermost mass ring 3, ensuring that each mass ring 3 and the central mass block 2 can vibrate independently without interfering with each other, thereby avoiding the change of resonance frequency caused by height difference and improving the stability and sound insulation effect of each order metamaterial structure.

[0045] The natural frequency f of the first-order acoustic metamaterial 1 The formula Calculated, where K is the stiffness of film 1, M 1 is the equivalent mass of the film 1 of the first-order acoustic metamaterial at the center, M mass is the mass of the central mass block 2.

[0046] From the 2nd order onwards, the formula for calculating the natural frequency of the nth-order acoustic metamaterial is: Where Mn is the equivalent mass of the film at the center corresponding to the nth order, M e,n-1 is the equivalent mass of the n-1th order acoustic metamaterial.

[0047] That is: the natural frequency f of the second-order acoustic metamaterial 2 The formula Calculated, where M e,1 =M 1 +M mass +Mframe,1 , M frame,1 is the mass of the first mass ring.

[0048] The natural frequency of the third-order acoustic metamaterial:

[0049] Calculated, where M e,2 =M e,1 +M frame,2 , M frame,2 is the mass of the second mass ring.

[0050] For higher order metamaterial structures, the natural frequency f n The formula Calculated, where M e,n-1 =M e,n-2 +M frame,n The recursive relationship makes the natural frequency distribution of each level of metamaterial structure more uniform, avoiding excessive concentration in a single frequency band, thus achieving efficient sound insulation in a wide frequency band. The precise design of the central mass block 2 and each order of metamaterial structure ensures that each metamaterial structure has a different natural frequency, thus achieving effective sound insulation in multiple frequency bands.

[0051] The height of the nth mass ring 3 is h n , the height difference between adjacent mass rings 3 is Δh,

[0052] ω=2πf n ,

[0053] Among them C 0 is the speed of sound in air, and ω is the angular frequency.

[0054] When the film is square, a is the side length. When the film is circular, a is the diameter. When the film is other shapes, a is the equivalent diameter of the film, and the equivalent diameter a=4A / L, A is the area of ​​the film, and L is the perimeter of the film.

[0055] For example, the height difference between the first mass ring and the central mass block is: Δh 1 =h 1 -h mass The height difference between the second mass ring and the first mass ring is: Δh 2 =h 2 -h 1 The height difference between the third mass ring and the second mass ring is: Δh 3 =h 3 -h 2 .

[0056] The distance between adjacent mass rings is set according to the equivalent diameter between the corresponding films of each order.

[0057] Through more accurate calculations, the compactness and stability of the entire device are maintained, the accuracy of the module is increased, and it is more suitable for practical engineering applications. The height of the mass ring 3 increases layer by layer, so that the resonance effect can be achieved in different frequency ranges, thereby achieving a wide-band sound insulation effect.

[0058] The thickness d of the film is calculated based on the stiffness K of the film, which conforms to the following formula: Wherein, E is Young's modulus, and μ is Poisson's ratio. By precisely controlling these parameters, the stiffness of the film 1 is optimized, and the sound insulation effect is further improved.

[0059] The outermost mass ring 3 is used to support the entire structure, and the materials of the remaining mass rings 3 can also be made of high specific stiffness materials such as steel, aluminum alloy, carbon fiber or engineering ABS plastic. Steel is selected as the material, which has high strength and stability; aluminum alloy is selected, which is light and easy to transport and install. The shape of the mass ring 3 can be adjusted according to actual needs, and the common ones are square, circular, regular hexagonal or triangular.

[0060] By setting a multi-order mass ring and a central mass block 2 structure on the metal film 1, a resonance effect in different frequency ranges is achieved, thereby forming a broadband sound insulation characteristic. At the same time, the use of the metal film 1 improves the weather resistance and service life of the product, and solves the problem that the traditional non-metal film 1 is easily damaged in harsh environments. This design not only improves the sound insulation effect, but also extends the service life of the product, and is suitable for various indoor and outdoor environments.

[0061] Example 2

[0062] The difference between this embodiment and the embodiment is that in this embodiment, five mass rings are arranged, that is, m=5, and n=1, 2, 3, 4, 5.

[0063] like Figure 5 As shown in , the central mass block 2 is fixed on the film 11 inside the first mass ring 31 to form a first-order acoustic metamaterial;

[0064] The area surrounded by the second mass ring 32 forms a second-order acoustic metamaterial. Here, the area surrounded by the second mass ring 32 is composed of the second mass ring 32, the first mass ring 31, the central mass block 2 and the film 1 in the corresponding surrounding area.

[0065] The area surrounded by the third mass ring 33 forms a third-order acoustic metamaterial. Here, the area surrounded by the third mass ring 33 is composed of the third mass ring 33, the second mass ring 32, the first mass ring 31, the central mass block 2 and the film 1 in the corresponding surrounding area.

[0066] The area surrounded by the fourth mass ring 34 forms a fourth-order acoustic metamaterial. Here, the area surrounded by the fourth mass ring 34 is composed of the fourth mass ring 34, the third mass ring 33, the second mass ring 32, the first mass ring 31, the central mass block 2 and the film 1 in the corresponding surrounding area.

[0067] The area surrounded by the fifth mass ring 35 forms a fifth-order acoustic metamaterial. Here, the area surrounded by the fifth mass ring 35 is composed of the fifth mass ring 35, the fourth mass ring 34, the third mass ring 33, the second mass ring 32, the first mass ring 31, the central mass block 2, and the film 1 in the corresponding surrounding area.

[0068] Example 3

[0069] like Figure 6 As shown, the difference between this embodiment and embodiment 1 is that the shape of the mass ring 3 is set to a regular hexagon. The regular hexagonal design can provide more resonance paths, thereby further expanding the sound insulation band. The regular hexagonal design can also improve the rigidity and stability of the structure, reduce deformation and vibration, and can provide more degrees of freedom, so that different frequency components can propagate on different paths, thereby achieving a wider range of sound insulation effects. The regular hexagonal design also helps to improve the rigidity and stability of the structure, reduce deformation and vibration, and is particularly suitable for application in high-frequency vibration environments.

[0070] Example 4

[0071] This embodiment discloses a stepped multi-order broadband metal film acoustic metamaterial module sound insulation structure, which is composed of a plurality of unit modules, each of which is the stepped multi-order broadband metal film acoustic metamaterial module described in the above embodiment. These unit modules can be assembled in a specific arrangement to form a continuous sound insulation barrier. For example, a plurality of unit modules can be spliced ​​into a wall, or laid on the ground or ceiling.

[0072] like Figure 7 As shown, the stepped multi-order broadband metal film acoustic metamaterial modules in Example 1 are arrayed in two directions, the x direction and the y direction. The sound insulation structure can be used in a variety of scenarios such as building exterior walls, ceilings, floors, etc. to achieve a large-area broadband sound insulation effect.

[0073] The unit modules can be connected by bolts, snaps or adhesives. Sound-absorbing materials such as foam plastics and mineral wool boards can also be filled between the unit modules. These sound-absorbing materials can absorb some sound waves, reduce reflections and reverberations, and further improve sound insulation performance. A layer of sound insulation film can also be added on the back of the unit module to block the propagation path of sound waves and further enhance the sound insulation effect.

[0074] Preparation method

[0075] 1. Prepare the required materials: select suitable steel, aluminum alloy, carbon fiber or engineering ABS plastic as the mass ring material; select stainless steel or aluminum alloy as the film 1 material; prepare a central mass block 2 made of stainless steel.

[0076] 2. Processing the outermost mass ring 3: According to the design drawings, cut and process the required shape of the outermost mass ring 3 to ensure that the height of each level of mass ring 3 gradually decreases and presents a stepped distribution from the outside to the inside.

[0077] 3. Install the film 1: Install the selected metal film 1 inside the outermost mass ring 3, ensuring that the film 1 is flat and wrinkle-free.

[0078] 4. Fix the central mass block 2: fix the stainless steel central mass block 2 on the middle part of one side of the film 1 by welding or bonding.

[0079] 5. Setting the mass ring 3: setting a plurality of mass rings 3 on both sides of the film 1 in sequence, ensuring that the height of each mass ring 3 increases layer by layer, and the mass rings 3 located in the same vertical direction of the film 1 are symmetrical with each other with the film 1 as the center.

[0080] 6. Quality inspection: Conduct quality inspection on the assembled metamaterials to ensure that the connections between the components are firm and reliable and meet the design requirements.

[0081] The above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. The present invention is described in detail with reference to the preferred embodiments. It should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, and should be included in the scope of the claims of the present invention.

Claims

1. A stepped multi-order broadband metal film acoustic metamaterial, characterized in that: It comprises a film (1), a central mass block (2) arranged at the center of the film (1), and m mass rings (3), wherein the central mass block (2) is arranged at the center, m is a natural number greater than 1, and the m mass rings (3) are arranged in sequence from the center to the outside, the mass rings (3) are arranged around the periphery of the central mass block (2) and are closed in a ring shape, and the heights of the mass rings (3) gradually increase; The material of the film (1) is metal or metal alloy.

2. The stepped multi-order broadband metal film acoustic metamaterial module according to claim 1 is characterized in that: The area surrounded by the nth mass ring (3) forms an nth-order acoustic metamaterial, where n is any natural number greater than or equal to 1 and less than or equal to m; The height of the central mass block (2) is h mass , mass is M mass ; The stiffness of the film is K; The natural frequency of the nth-order acoustic metamaterial is f n , where the calculation formula for the natural frequency of the first-order acoustic metamaterial is The calculation formula for the natural frequency of the nth-order acoustic metamaterial is: Where Mn is the equivalent mass of the film at the center corresponding to the nth order, M e,n-1 is the equivalent mass of the n-1th order acoustic metamaterial.

3. The stepped multi-order broadband metal film acoustic metamaterial module according to claim 1, characterized in that: The thickness of the film (1) is less than or equal to 0.2 mm.

4. The stepped multi-stage broadband metal film acoustic metamaterial module according to claim 2, characterized in that: The thickness d of the film is calculated according to the stiffness K of the film, which conforms to the following formula: Where E is Young's modulus and μ is Poisson's ratio.

5. The stepped multi-stage broadband metal film acoustic metamaterial module according to claim 2, characterized in that: The height of the nth mass ring (3) is h n , the height difference between adjacent mass rings (3) is Δh, ω=2πf n , where C0 is the speed of sound in air, ω is the angular frequency, when the film is square, a is the side length; when the film is circular, a is the diameter; when the film is other shapes, a is the equivalent diameter of the film, at this time the equivalent diameter a = 4A / L, A is the area of ​​the film, and L is the circumference of the film.

6. The stepped multi-stage broadband metal film acoustic metamaterial module according to claim 1, characterized in that: The mass rings (3) are provided in three numbers.

7. The stepped multi-order broadband metal film acoustic metamaterial module according to claim 1, characterized in that: The material of the mass ring (3) is steel, aluminum alloy, carbon fiber, or engineering ABS plastic; The material of the central mass block (2) is stainless steel; The film (1) is made of stainless steel or aluminum alloy.

8. The stepped multi-order broadband metal film acoustic metamaterial module according to claim 1, characterized in that: The mass rings (3) are located on both sides of the film (1) and are symmetrically arranged; The shape formed by the mass ring (3) is a square, a circle, a regular hexagon or a triangle.

9. The stepped multi-order broadband metal film acoustic metamaterial module according to claim 8, characterized in that: The mass ring (3) is centrally symmetrical with respect to the central mass block (2) along the plane where the film (1) is located.

10. A stepped multi-stage broadband metal film acoustic metamaterial module sound insulation structure, characterized in that: It is composed of the stepped multi-order broadband metal film acoustic metamaterial module array as described in any one of claims 1 to 9.

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