A sound absorption structure and design method for transformer low-frequency noise treatment

Abstract

The application relates to a sound absorption structure and a design method for low-frequency noise treatment of a transformer, wherein the sound absorption structure comprises a homogeneous plate and a thin-film acoustic metamaterial soundproof cover; the thin-film acoustic metamaterial soundproof cover is connected to the homogeneous plate and encloses a cuboid with a cavity; the homogeneous plate is located at the bottom of the cuboid, at least one circular hole is arranged on the homogeneous plate, and the circular hole is communicated with the cavity of the cuboid; the thin-film acoustic metamaterial soundproof cover comprises at least five first metamaterial soundproof plates, and each of the four sides and the top of the cuboid corresponds to at least one first metamaterial soundproof plate; the first metamaterial soundproof plate comprises a first thin-film body and a first mass block connected to the center of the first thin-film body, and the first thin-film body is in a square shape. The application has the advantages of considering the noise reduction effect and light weight.

Description

Technical Field

[0001] This invention relates to the field of noise control technology, and in particular to a sound-absorbing structure and design method for controlling low-frequency noise in transformers. Background Technology

[0002] With the rapid advancement of urbanization and the continuous rise in electricity demand in my country, the construction of substations adjacent to residential areas is becoming increasingly common. This has led to low-frequency noise pollution from transformers, which has become a prominent environmental problem causing public complaints and affecting the stable operation of the power grid. Transformer noise is mainly caused by the magnetostriction of silicon steel sheets and the electromagnetic force of coils, with its energy concentrated in the 50-200Hz range. Low-frequency sound waves have long wavelengths, strong penetrating power, and slow attenuation, making traditional control methods ineffective and extremely difficult to manage. Currently, the best sound-absorbing transformer noise reduction measure is the use of Helmholtz resonators, but these often have metal outer walls, resulting in large and heavy casings at low frequencies, making it difficult to achieve both performance and lightweight design. Conversely, using lightweight casings would soften the acoustic boundaries, reducing sound pressure transmission and resonance absorption. In summary, existing transformer noise reduction measures struggle to balance low-frequency performance with lightweight design. Furthermore, for safety reasons, corresponding noise reduction measures must also consider durability and fire safety requirements.

[0003] Therefore, developing new technologies and materials that can effectively suppress low-frequency noise and meet practical engineering requirements is of extremely urgent practical significance and broad social value. Summary of the Invention

[0004] The purpose of this invention is to provide a sound-absorbing structure and design method for low-frequency noise control of transformers, which can achieve both good noise reduction effect and lightweight structure.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A sound-absorbing structure for low-frequency noise control in transformers includes a homogeneous plate and a thin-film acoustic metamaterial sound insulation cover. The thin-film acoustic metamaterial sound insulation cover is connected to the homogeneous plate and forms a cuboid with a cavity. The homogeneous plate is located at the bottom of the cuboid and has at least one circular hole that communicates with the cavity of the cuboid. The thin-film acoustic metamaterial sound insulation cover includes at least five first metamaterial sound insulation panels, with at least one first metamaterial sound insulation panel corresponding to each of the four sides and the top of the cuboid. Each first metamaterial sound insulation panel includes a first thin-film body and a first mass block connected to the center of the first thin-film body. The first thin-film body is square.

[0006] Preferably, the top of the cuboid corresponds to a first metamaterial sound insulation panel; the first metamaterial sound insulation panels corresponding to the sides of the cuboid are arranged in a row between the top and bottom of the cuboid.

[0007] Preferably, it further includes a porous sound-absorbing cover disposed outside the thin-film acoustic metamaterial soundproof cover for absorbing high-frequency noise, the porous sound-absorbing cover being connected to a homogenizing plate, and the porous sound-absorbing cover being made of porous sound-absorbing material.

[0008] Preferably, each side of the porous sound-absorbing cover is provided with N layers of second thin film, and the top surface of the porous sound-absorbing cover is provided with N layers of third thin film, where N is a positive integer greater than or equal to 1; both the second and third thin film layers include a plurality of second metamaterial sound-insulating plates arranged in an array, each second metamaterial sound-insulating plate including a second thin film body and a second mass block connected to the center of the second thin film body, the second thin film body being square; the noise frequency absorbed by the second and third thin film layers is higher than the noise frequency absorbed by the thin film acoustic metamaterial sound-insulating cover, and the noise frequency absorbed by the second and third thin film layers is lower than the noise frequency absorbed by the porous sound-absorbing cover, each second thin film layer absorbs a different pimson frequency, and each third thin film layer absorbs a different pimson frequency.

[0009] Preferably, a homogenizing plate is connected to the bottom of the second film layer; the spacing between adjacent second film layers is equal to the spacing between adjacent third film layers.

[0010] Preferably, both the first and second film bodies are made of aluminum alloy or stainless steel; the homogenizing plate is made of aluminum alloy, magnesium alloy or PPS.

[0011] Preferably, one circular hole is provided, and the circular hole is located at the center of the bottom of the cuboid.

[0012] The present invention also discloses a design method for the above-mentioned sound-absorbing structure, which includes the following steps: Establish low-frequency sound absorption frequency f , q Computational architecture:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] in, This represents the sound absorption coefficient. Indicates the sound absorption coefficient The maximum value, where x represents acoustic resistivity, y represents acoustic reactance, R represents acoustic resistance, and V represents the volume of the cavity. Let f represent air density, c0 represent sound speed, M represent sound mass, ω represent angular frequency, μ represent air viscosity coefficient, h represent the depth of the circular hole, d represent the diameter of the circular hole, A represent the side length of the cavity, H represent the height of the cavity, f represent the frequency of the sound, and C represent sound volume. Establish low-frequency sound insulation frequency f MAM1 Computational architecture:

[0022]

[0023] Where a1 represents the side length of the first thin film body, K represents the modal factor of the first thin film bulk. mem1 M represents the equivalent stiffness of the first thin film body. mem1 M represents the equivalent mass of the first thin film body at its center. mass1 Indicates the mass of the first mass block; Parameter optimization Substituting the conditions a1=A and H=nA into the low-frequency sound absorption frequency f , q The calculation system and low-frequency sound insulation frequency f MAM1 In the computational system, A, H, d, and h are calculated; where n is a positive integer greater than or equal to 1; Reverse design of the first metamaterial sound insulation panel Based on the calculated A, combined with the low-frequency sound insulation frequency f MAM1 The calculation system determines the thickness of the first thin film body, the material of the first thin film body, the size of the first mass block, and the material of the first mass block.

[0024] Preferably, the design step B of the porous sound-absorbing cover is also included, which comprises the following steps: B1. Determine the high-frequency sound absorption frequency f ,h q B2. Determine the thickness of the porous sound-absorbing cover according to the following formula. :

[0025] Where i = 1, 2; This indicates the thickness of the top of the porous sound-absorbing cover. This indicates the thickness of the sidewall of the porous sound-absorbing cover; B3. Based on the thickness of the porous sound-absorbing cover Determine the material composition of the porous sound-absorbing material.

[0026] Preferably, the design step of the second metamaterial sound insulation panel is also included, which includes the following steps: C1. Based on the determined low-frequency sound absorption frequency f , q and high-frequency sound absorption frequency f ,h q Determine the sound absorption frequency range f of the second and third thin film layers. MAM2 ; C2. Optimize the porous sound-absorbing cover and determine the side length a2 of the second metamaterial sound insulation plate according to the following conditions:

[0027]

[0028] Where n1 is a positive integer greater than or equal to 1, and n2 is a positive integer greater than or equal to 1; C3. Recommended sound absorption frequency range f MAM2 Computational architecture:

[0029] in, K represents the modal factor of the second thin film bulk. mem2 M represents the equivalent stiffness of the second thin film bulk. mem2 M represents the equivalent mass of the second thin film at its center. mass2 Indicates the mass of the second mass block; C4. The determined side length a2 of the second metamaterial sound insulation panel is combined with the sound absorption frequency range f. MAM2 The calculation system determines the thickness of the second thin film body, the material of the second thin film body, the size of the second mass block, and the material of the second mass block.

[0030] The present invention has the following beneficial effects: 1. This invention constructs a cuboid with a cavity by using a homogeneous plate and a thin-film acoustic metamaterial sound insulation cover. This cuboid is essentially a Helmholtz resonant sound absorption structure. However, compared with the traditional Helmholtz resonant sound absorption structure, this invention utilizes the local resonance of the first metamaterial sound insulation plate to generate an excellent low-frequency acoustic bandgap, so that its peak sound insulation frequency matches the sound absorption frequency of the Helmholtz resonant structure. This achieves performance optimization (increased sound absorption coefficient), good noise reduction effect, and also lightweight effect.

[0031] 2. For sound waves passing through the first metamaterial sound insulation panel (outside the acoustic band gap of the first metamaterial sound insulation panel), a porous sound-absorbing cover is used for mid-to-high frequency sound absorption. The second and third thin-film layers on the outer side of the porous sound-absorbing cover are used to isolate the unabsorbed mid-to-high frequency sound waves. This invention, through the coordinated use of the thin-film acoustic metamaterial sound insulation cover, the porous sound-absorbing cover, and the second and third thin-film layers, solves the defects of existing Helmholtz resonators, such as single-frequency sound absorption, narrow bandwidth, and no effect at high frequencies. This results in a wider sound absorption bandwidth for the sound-absorbing structure of this invention, enabling low, mid, and high-frequency sound absorption and further improving the noise reduction effect.

[0032] 3. The porous sound-absorbing cover is placed in a sealed space enclosed by a thin-film acoustic metamaterial sound insulation cover, a second thin-film layer, a third thin-film layer, and a homogeneous plate. The porous sound-absorbing material does not come into contact with external air and moisture, thus avoiding the problems of water absorption, collapse, and pulverization performance degradation, and also enabling the overall structure to achieve fire-resistant properties. In addition, the first and second thin-film bodies are made of aluminum alloy or stainless steel, which can further improve the fire resistance. Attached Figure Description

[0033] Figure 1 This is a simplified view of the sound-absorbing structure of the present invention.

[0034] Figure 2 This is a perspective view of the rectangular block of the present invention.

[0035] Figure 3 This is a simulation diagram of the sound absorption coefficient for Example 1 and the comparative example.

[0036] Figure 4 This is a simulation diagram of the sound absorption coefficient in Example 2.

[0037] Explanation of symbols for main components: Homogeneous plate 1, thin-film acoustic metamaterial sound insulation cover 2, porous sound absorption cover 3, second thin film layer 4, third thin film layer 5, cavity 6, round hole 7, first metamaterial sound insulation plate 8, first thin film body 9, first mass block 10, second metamaterial sound insulation plate 11, second thin film body 12, second mass block 13. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1-2 As shown, this invention discloses a sound-absorbing structure for low-frequency noise control in transformers, comprising a homogeneous plate, a thin-film acoustic metamaterial sound insulation cover, a porous sound-absorbing cover, and a reinforcing sound-absorbing outer layer. The homogeneous plate is made of metal or non-metal materials such as aluminum alloy, magnesium alloy, or PPS, which have certain rigidity and fire resistance.

[0040] A thin-film acoustic metamaterial soundproof cover is connected to a homogeneous plate, and the two together form a cuboid with a cavity, which is also cuboid in shape. The homogeneous plate is located at the bottom of the cuboid, and at least one circular hole (preferably only one circular hole is provided, and it is located at the center of the bottom of the cuboid) is provided on the homogeneous plate, that is, the cuboid is a Helmholtz resonator.

[0041] The thin-film acoustic metamaterial soundproof cover includes at least five first metamaterial soundproof panels, meaning that at least one first metamaterial soundproof panel corresponds to each of the four sides and the top of the cuboid. In a preferred embodiment, one first metamaterial soundproof panel corresponds to the top of the cuboid; the first metamaterial soundproof panels corresponding to the sides of the cuboid are arranged in a row between the top and bottom of the cuboid. This arrangement is equivalent to setting multiple cells on the thickness H, minimizing the parameter A, thus maximizing the area ratio of the pores to the homogeneous plate, thereby obtaining the maximum sound absorption coefficient.

[0042] The first metamaterial sound insulation panel includes a first thin film body and a first mass block connected to the center of the first thin film body. The first thin film body is square, and the first mass block is also preferably square. The first thin film body can be made of metal or non-metal film. In this case, to adapt to the transformer installation environment, aluminum alloy or stainless steel with high fire resistance is preferred.

[0043] The local resonance between the first thin film body and the first mass block on the first metamaterial sound insulation board can generate an excellent low-frequency acoustic bandgap, so that its peak sound insulation frequency matches the sound absorption frequency of the Helmholtz resonance structure, thereby effectively absorbing the low-frequency sound waves generated by the transformer and playing a noise reduction role.

[0044] The porous sound-absorbing cover is made of porous sound-absorbing material and is installed outside the thin-film acoustic metamaterial sound insulation cover. The lower edge of the porous sound-absorbing cover is connected to (aggregate) a homogeneous plate. The porous sound-absorbing cover is used to absorb high-frequency noise that passes through the first metamaterial sound insulation plate.

[0045] The reinforcing sound-absorbing outer layer includes N second thin-film layers disposed on each side of the porous sound-absorbing cover and N third thin-film layers disposed on the outer top surface of the porous sound-absorbing cover, where N is a positive integer greater than or equal to 1. A homogeneous plate is connected to the bottom of each of the second thin-film layers; the spacing between adjacent second thin-film layers is equal to the spacing between adjacent third thin-film layers. The second and third thin-film layers are used to absorb mid-to-high frequency sound waves that pass through the first metamaterial sound insulation plate and the porous sound-absorbing cover. That is, the noise frequencies absorbed by the second and third thin-film layers are higher than the noise frequencies absorbed by the thin-film acoustic metamaterial sound insulation cover, and lower than the noise frequencies absorbed by the porous sound-absorbing cover. The absorption frequencies of each second thin-film layer and each third thin-film layer are different to broaden the sound absorption frequency band.

[0046] Both the second and third thin film layers include several second metamaterial sound-insulating panels arranged in an array. Each second metamaterial sound-insulating panel includes a second thin film body and a second mass block connected to the center of the second thin film body. The second thin film body is square. The structure of the second metamaterial sound-insulating panel is similar to that of the first metamaterial sound-insulating panel and will not be described in detail here.

[0047] Therefore, different transformers produce different noise frequencies. Thus, in other embodiments, a reinforcing sound-absorbing outer layer may not be provided, or neither a reinforcing sound-absorbing outer layer nor a porous sound-absorbing cover may be provided, to suit the actual application.

[0048] The design method of the above-mentioned sound-absorbing structure (including a reinforcing sound-absorbing outer layer and a porous sound-absorbing cover) includes the following steps: A. The design steps for a thin-film acoustic metamaterial soundproof enclosure are as follows: Establish low-frequency sound absorption frequency f , q Computational architecture:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] in, This represents the sound absorption coefficient. Indicates the sound absorption coefficient The maximum value, where x represents acoustic resistivity, y represents acoustic reactance, R represents acoustic resistance, and V represents the volume of the cavity. c represents air density, c0 represents sound speed, M represents sound mass, ω represents angular frequency, μ represents air viscosity coefficient, h represents the depth of the circular hole, d represents the diameter of the circular hole, A represents the side length of the cavity, H represents the height of the cavity, f represents the frequency of the sound (audible to the human ear (20-20000Hz)), and C represents sound volume.

[0058] Establish low-frequency sound insulation frequency f MAM1 Computational architecture:

[0059]

[0060] Where a1 represents the side length of the first thin film body, K represents the modal factor of the first thin film bulk. mem1 M represents the equivalent stiffness of the first thin film body. mem1 M represents the equivalent mass of the first thin film body at its center. mass1 This represents the mass of the first mass block.

[0061] Parameter optimization Substituting the conditions a1=A and H=nA (n is a positive integer greater than or equal to 1) into the low-frequency sound absorption frequency f , q The calculation system and low-frequency sound insulation frequency f MAM1 In the computational system, A, H, d, and h are calculated.

[0062] Reverse design of the first metamaterial sound insulation panel Based on the calculated A, combined with the low-frequency sound insulation frequency f MAM1 The calculation system determines the thickness of the first thin film body, the material of the first thin film body, the size of the first mass block, and the material of the first mass block.

[0063] B. Design steps for a porous sound-absorbing cover: B1. Determine the high-frequency sound absorption frequency f ,h q .

[0064] B2. Determine the thickness of the porous sound-absorbing cover according to the following formula. :

[0065] Where i = 1, 2. This indicates the thickness of the top of the porous sound-absorbing cover. This indicates the thickness of the sidewall of the porous sound-absorbing cover.

[0066] B3. Based on the thickness of the porous sound-absorbing cover Determine the material composition of the porous sound-absorbing material.

[0067] It should be noted that when no reinforcing sound-absorbing outer layer is added, the thickness and material (flow resistance, porosity, etc.) of the porous sound-absorbing cover can be determined after step B3 is completed, and no further changes are needed. However, if a reinforcing sound-absorbing outer layer is required, the conclusions of steps B2 and B3 are pending, and the thickness and material of the porous sound-absorbing cover will be determined after step C2 is executed.

[0068] C. Design steps for the second metamaterial sound insulation panel: C1. Based on the determined low-frequency sound absorption frequency f , q and high-frequency sound absorption frequency f ,h q Determine the sound absorption frequency range f of the second and third thin film layers. MAM2 .

[0069] C2. Optimize the porous sound-absorbing cover and determine the side length a2 of the second metamaterial sound insulation plate according to the following conditions: (n1 is a positive integer greater than or equal to 1) (n2 is a positive integer greater than or equal to 1) Step C2 is used to reverse-optimize the porous sound-absorbing cover to ensure the compactness of the overall structure.

[0070] C3. Recommended sound absorption frequency range f MAM2 Computational architecture:

[0071] in, K represents the modal factor of the second thin film bulk. mem2 M represents the equivalent stiffness of the second thin film bulk. mem2M represents the equivalent mass of the second thin film at its center. mass2 This indicates the mass of the second mass block.

[0072] C4. The determined side length a2 of the second metamaterial sound insulation panel is combined with the sound absorption frequency range f. MAM2 The calculation system determines the thickness of the second thin film body, the material of the second thin film body, the size of the second mass block, and the material of the second mass block.

[0073] Example 1 With low-frequency sound absorption frequency f , q Taking 110Hz as an example, calculations yield A=5cm, H=15cm, d=3mm, and h=4mm. Further, the side length a1 of the first thin film body is determined to be 5cm, the thickness to be 0.075mm, and the material to be aluminum alloy. The first mass block is a 15*15*1mm stainless steel sheet.

[0074] Simulations using the COMSOL acoustic-vibration coupling model yielded comparative results for the sound absorption coefficients of a closed cavity of the same size (A=5cm, H=15cm, d=3mm, h=4mm), with a 1.5mm aluminum plate shell (Comparative Example 1), and the aforementioned aluminum alloy thin-film metamaterial structure (homogeneous plate and thin-film acoustic metamaterial soundproof enclosure). Figure 3 As shown in the figure, the maximum sound absorption coefficient increased from 0.7 to 0.87, an increase of 18.6%. In terms of weight, it decreased from 187g to 106g, a weight reduction of 43%.

[0075] Example 2 Based on Example 1, using a high-frequency sound absorption frequency f ,h q Taking 1500Hz as an example, the calculation yields: =1.0cm, =5.5cm, a2=4.0cm. The sound absorption coefficient of the sound-absorbing structure is obtained through simulation using the COMSOL acoustic-vibration coupling model, as shown below. Figure 4As shown in the figure, the peak sound absorption coefficient at 110Hz is 0.785, and the sound absorption coefficient above 600Hz reaches 0.5 or higher. Therefore, the frequency band of the reinforcing sound-absorbing outer layer can be designed to be 200-600Hz, corresponding to N=2, that is, setting two layers of the second thin film layer and two layers of the third thin film layer. For the second thin film body close to the porous sound-absorbing cover, it is configured as an aluminum alloy thin film with a side length of 4.0cm and a thickness of 0.1mm, and its corresponding second mass block is a 10*10*1mm stainless steel sheet. For the second thin film body far from the porous sound-absorbing cover, it is configured as a stainless steel thin film with a side length of 4.0cm and a thickness of 0.1mm, and its corresponding second mass block is a 10*10*1mm stainless steel sheet.

[0076] Through the above design, the external dimensions of the sound-absorbing mechanism in this embodiment are 16*16*16cm, and the total weight of the sound-absorbing mechanism in this embodiment is 292.0g. The outer shell of the same size with a 1.0mm aluminum plate on the outer wall weighs 437.97g. The weight reduction ratio of this embodiment is 33.3%.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A sound-absorbing structure for controlling low-frequency noise in transformers, characterized in that: The device includes a homogeneous plate and a thin-film acoustic metamaterial soundproof cover. The thin-film acoustic metamaterial soundproof cover is connected to the homogeneous plate and forms a cuboid with a cavity. The homogeneous plate is located at the bottom of the cuboid and has at least one circular hole that communicates with the cavity of the cuboid. The thin-film acoustic metamaterial soundproof cover includes at least five first metamaterial soundproof plates, with at least one first metamaterial soundproof plate corresponding to each of the four sides and the top of the cuboid. Each first metamaterial soundproof plate includes a first thin-film body and a first mass block connected to the center of the first thin-film body. The first thin-film body is square.

2. The sound-absorbing structure for low-frequency noise control in transformers according to claim 1, characterized in that: The top of the cuboid corresponds to a first metamaterial sound insulation panel; the first metamaterial sound insulation panels corresponding to the sides of the cuboid are arranged in a row between the top and bottom of the cuboid.

3. The sound-absorbing structure for low-frequency noise control in transformers according to claim 1, characterized in that: It also includes a porous sound-absorbing cover disposed outside the thin-film acoustic metamaterial soundproof cover for absorbing high-frequency noise, the porous sound-absorbing cover being connected to a homogenizing plate and being made of porous sound-absorbing material.

4. The sound-absorbing structure for low-frequency noise control in transformers according to claim 3, characterized in that: The porous sound-absorbing cover has N layers of second thin film on each side exterior and N layers of third thin film on the top exterior, where N is a positive integer greater than or equal to 1. Both the second and third thin film layers include several arrayed second metamaterial sound-insulating panels. Each second metamaterial sound-insulating panel includes a second thin film body and a second mass block connected to the center of the second thin film body. The second thin film body is square. The noise frequencies absorbed by the second and third thin film layers are higher than those absorbed by the thin-film acoustic metamaterial sound-insulating cover, and lower than those absorbed by the porous sound-absorbing cover. The pimson frequencies absorbed by each second thin film layer and each third thin film layer are different.

5. The sound-absorbing structure for low-frequency noise control in transformers according to claim 4, characterized in that: The bottom of the second film layer is connected to a homogenizing plate; the spacing between adjacent second film layers is equal to the spacing between adjacent third film layers.

6. The sound-absorbing structure for low-frequency noise control in transformers according to claim 4, characterized in that: Both the first and second film bodies are made of aluminum alloy or stainless steel; the homogenizing plate is made of aluminum alloy, magnesium alloy or PPS.

7. The sound-absorbing structure for low-frequency noise control in transformers according to claim 1, characterized in that: One circular hole is provided, and the circular hole is located at the center of the bottom of the cuboid.

8. The design method of the sound-absorbing structure according to any one of claims 1-7, characterized in that, Includes the following steps: Establish low-frequency sound absorption frequency f , q Computational architecture: in, This represents the sound absorption coefficient. Indicates the sound absorption coefficient The maximum value, where x represents acoustic resistivity, y represents acoustic reactance, R represents acoustic resistance, and V represents the volume of the cavity. Let f represent air density, c0 represent sound speed, M represent sound mass, ω represent angular frequency, μ represent air viscosity coefficient, h represent the depth of the circular hole, d represent the diameter of the circular hole, A represent the side length of the cavity, H represent the height of the cavity, f represent the frequency of the sound, and C represent sound volume. Establish low-frequency sound insulation frequency f MAM1 Computational architecture: Where a1 represents the side length of the first thin film body, K represents the modal factor of the first thin film bulk. mem1 M represents the equivalent stiffness of the first thin film body. mem1 M represents the equivalent mass of the first thin film body at its center. mass1 Indicates the mass of the first mass block; Parameter optimization Substituting the conditions a1=A and H=nA into the low-frequency sound absorption frequency f , q The calculation system and low-frequency sound insulation frequency f MAM1 In the computational system, A, H, d, and h are calculated; where n is a positive integer greater than or equal to 1; Reverse design of the first metamaterial sound insulation panel Based on the calculated A, combined with the low-frequency sound insulation frequency f MAM1 The calculation system determines the thickness of the first thin film body, the material of the first thin film body, the size of the first mass block, and the material of the first mass block.

9. The design method according to claim 8, characterized in that, It also includes design step B for the porous sound-absorbing cover, which includes the following steps: B1. Determine the high-frequency sound absorption frequency f ,h q B2. Determine the thickness of the porous sound-absorbing cover according to the following formula. : Where i = 1, 2; This indicates the thickness of the top of the porous sound-absorbing cover. This indicates the thickness of the sidewall of the porous sound-absorbing cover; B3. Based on the thickness of the porous sound-absorbing cover Determine the material composition of the porous sound-absorbing material.

10. The design method according to claim 9, characterized in that: It also includes the design steps for a second metamaterial sound insulation panel, which include the following steps: C1. Based on the determined low-frequency sound absorption frequency f , q and high-frequency sound absorption frequency f ,h q Determine the sound absorption frequency range f of the second and third thin film layers. MAM2 ; C2. Optimize the porous sound-absorbing cover and determine the side length a2 of the second metamaterial sound insulation plate according to the following conditions: Where n1 is a positive integer greater than or equal to 1, and n2 is a positive integer greater than or equal to 1; C3. Recommended sound absorption frequency range f MAM2 Computational architecture: in, K represents the modal factor of the second thin film bulk. mem2 M represents the equivalent stiffness of the second thin film bulk. mem2 M represents the equivalent mass of the second thin film at its center. mass2 Indicates the mass of the second mass block; C4. The determined side length a2 of the second metamaterial sound insulation panel is combined with the sound absorption frequency range f. MAM2 The calculation system determines the thickness of the second thin film body, the material of the second thin film body, the size of the second mass block, and the material of the second mass block.

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