Broadband ventilation and sound insulation acoustic metasurface structure, manufacturing method and application

Abstract

The broadband ventilation and sound insulation acoustic metasurface structure comprises a cylindrical body, and an axial through hole is formed in the cylindrical body; n layers of containing cavities are sequentially formed in the cylindrical body in the axis direction, and N is larger than or equal to 2; the accommodating cavities are isolated from one another; each layer of accommodating cavity is provided with an opening facing the through hole; and the sizes of the axial sections of the accommodating cavities in different layers are different. The invention further discloses a manufacturing method of the broadband ventilation and sound insulation acoustic metasurface structure, a 3D printing method is adopted for manufacturing, and a 3D printing material is alloy powder or hard plastic powder. The invention further discloses application of the broadband ventilation and sound insulation acoustic metasurface structure. The broadband ventilation and sound insulation acoustic metasurface structure is used for constructing a building structure with ventilation and noise reduction functions. Noise can be effectively isolated, air flow is not hindered, and the double requirements of modern buildings and industrial equipment for ventilation and noise reduction are met.

Description

Technical Field

[0001] The present invention relates to the technical field of metasurface structures, and particularly to a broadband ventilation and sound insulation acoustic metasurface structure, a manufacturing method and an application thereof. Background Art

[0002] Currently, ventilation and sound insulation metamaterials are an innovative acoustic structure designed on the sub-wavelength scale. Through carefully designed microstructural units, they not only achieve efficient noise attenuation but also maintain excellent air circulation performance. Utilizing mechanisms such as local resonance, interference, and multiple scattering, this metamaterial can significantly reduce noise transmission within a specific frequency band and achieve low-resistance ventilation, showing broad prospects in noise control applications in modern buildings, transportation facilities, and industrial equipment.

[0003] Traditional ventilation and sound insulation technologies often face a trade-off between ventilation efficiency and noise isolation effect. Their fixed microstructural parameters limit the width of the applicable noise frequency band, resulting in poor performance in broadband noise environments. To cover a wider frequency range, existing solutions usually require a combination of multiple structures, which not only increases the complexity of design and manufacturing but also raises the system cost. Summary of the Invention

[0004] The present invention provides a broadband ventilation and sound insulation acoustic metasurface structure, a manufacturing method and an application thereof to solve the technical problems existing in the known art.

[0005] The technical solution adopted by the present invention to solve the technical problems existing in the known art is as follows:

[0006] A broadband ventilation and sound insulation acoustic metasurface structure includes a columnar body with an axial through-hole provided therein; N layers of cavities are sequentially arranged along the axial direction within the columnar body, where N≥2; the cavities of each layer are isolated from each other; each layer of cavity has an opening facing the through-hole, and the axial dimension of each layer of cavity is greater than the axial dimension of its opening; the axial cross-sectional dimensions of the cavities of different layers are different from each other.

[0007] Furthermore, each layer is provided with a plurality of unit cavities. The plurality of unit cavities of each layer are isolated from each other and are evenly distributed circumferentially, and each unit cavity has an opening facing the through-hole.

[0008] Furthermore, the cross-section of the unit cavity of each layer is fan-shaped.

[0009] Furthermore, the cavities of each layer are interconnected to form an annular cavity; the annular cavity has an annular opening facing the through-hole; the axial cross-sectional dimensions of the annular cavities of each layer are different from each other.

[0010] Furthermore, the axial cross-section of each layer of annular cavity is circular or elliptical or square.

[0011] Furthermore, N = 2; the annular opening of the first-layer annular cavity has a radial dimension of 2 - 4 mm and an axial dimension of 8 - 12 mm; the cross-section of the first-layer annular cavity is square, with a radial dimension of 19 - 21 mm and an axial dimension of 35 - 40 mm; the annular opening of the second-layer annular cavity has a radial dimension of 7 - 9 mm and an axial dimension of 5 - 7 mm; the cross-section of the second-layer annular cavity is square, with a radial dimension of 13 - 15 mm and an axial dimension of 80 - 84 mm; assuming the axial direction is perpendicular to the horizontal direction, the second-layer annular cavity is located below the first-layer annular cavity; the distance between the center of the annular opening of the second-layer annular cavity and the bottom surface of the columnar body is 16 - 20 mm.

[0012] Furthermore, the columnar body is a cuboid or a cylinder.

[0013] Furthermore, the ratio of the outer diameter to the height of the cylinder is 1.2 - 2, and the ratio of the diameter of the through-hole inside the cylinder to the height is 0.1 - 0.25.

[0014] The present invention also provides a manufacturing method for the above broadband ventilation and sound insulation acoustic metasurface structure, which is manufactured by 3D printing. The 3D printing material is metal powder, alloy powder or hard plastic powder.

[0015] The present invention also provides an application of the above broadband ventilation and sound insulation acoustic metasurface structure, which is used to construct a building structure that is both ventilated and noise-reducing.

[0016] The advantages and positive effects of the present invention are as follows: The present invention provides a reflective broadband ventilation and sound insulation acoustic metasurface structure, which utilizes a columnar body based on a Fabry - Pérot cavity (Fabry - Pérot resonator), and multiple auxiliary cavities composed of Helmholtz resonators are opened inside the columnar body. These auxiliary cavities are connected to the Fabry - Pérot cavity through their rectangular necks and form a complete side branch channel by rotating one week along the axis.

[0017] The broadband sound insulation performance of the structure of the present invention is excellent. In the frequency range of 673 to 2468 Hz, a transmission loss continuously exceeding 10 dB can be achieved, and the average sound transmission loss reaches 23.8 dB, ensuring efficient suppression of broadband noise. By reasonably arranging the cavities and ventilation channels, the present invention can not only effectively isolate noise but also does not hinder air flow, meeting the dual requirements of modern buildings and industrial equipment for ventilation and noise reduction. The Helmholtz resonator structure adopted by the present invention is simple, can be 3D printed, and the manufacturing process is relatively simple, which is conducive to large-scale production and practical application promotion.

[0018] The present invention achieves effective attenuation of broadband noise while maintaining high ventilation efficiency. The present invention can be used as a tunable ventilation sound insulation metamaterial, which can simultaneously meet the dual requirements of broadband noise attenuation and efficient ventilation by optimizing the microstructure, thereby providing a more flexible and economical solution for practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a stereoscopic diagram of a broadband ventilation and sound insulation acoustic supersurface structure of the present invention.

[0020] Figure 2 It is an axially cut stereoscopic diagram of an embodiment of a broadband ventilation and sound insulation acoustic metasurface structure of the present invention.

[0021] Figure 3 It is a half-section view of an embodiment of a broadband ventilation and sound insulation acoustic metasurface structure of the present invention.

[0022] Figure 4 It is a schematic diagram of transmission loss of a broadband ventilation sound insulation acoustic metasurface structure of the present invention compared with a pure Fabry-Pérot cavity of the same size.

[0023] Figure 5 It is a schematic diagram of the energy coefficient of a broadband ventilation sound insulation acoustic metasurface structure of the present invention.

[0024] Figure 6 It is a schematic diagram of experimental results and simulation results of transmission loss of a broadband ventilation sound insulation acoustic metasurface structure of the present invention.

[0025] Figure 7 This is a diagram showing the broadband sound pressure attenuation function of a broadband ventilation sound insulation acoustic metasurface structure embodiment of the present invention when the frequency of a sound wave incident vertically from the bottom is 892 Hz.

[0026] Figure 8 This is a diagram showing the broadband sound pressure attenuation function of a broadband ventilation sound insulation acoustic metasurface structure embodiment of the present invention when the frequency of a sound wave incident vertically from the bottom is 1816 Hz.

[0027] Figure 9 A schematic diagram of the average flow velocity results under the condition of air flow under the conditions of an incident sound wave frequency of 892 Hz and a Mach number (Ma) of 0.1 using a broadband ventilation sound insulation acoustic metasurface structure embodiment of the present invention.

[0028] Figure 10 The figure is a schematic diagram of transmission loss results at different Mach numbers (Ma) using a broadband ventilation sound insulation acoustic metasurface structure embodiment of the present invention.

[0029] In the figure: 1. Columnar body; 2. First-layer annular cavity; 3. Second-layer annular cavity; 4. Annular opening of the first-layer annular cavity; 5. Annular opening of the second-layer annular cavity; 6. Through hole.

[0030] w is the wall thickness of the columnar body.

[0031] h is the height of the columnar body.

[0032] d1 is the outer diameter of the columnar body.

[0033] Φ1 is the outer circle diameter of the columnar body.

[0034] d2 is the inner diameter of the through hole in the columnar body.

[0035] Φ2 is the diameter of the through hole in the columnar body.

[0036] a1 is the radial dimension of the annular opening of the first-layer annular cavity.

[0037] b1 is the axial dimension of the annular opening of the first-layer annular cavity.

[0038] w1 is the radial dimension of the cross-section of the first-layer annular cavity.

[0039] h1 is the axial dimension of the cross-section of the first-layer annular cavity.

[0040] a2 is the radial dimension of the annular opening of the second-layer annular cavity.

[0041] b2 is the axial dimension of the annular opening of the second-layer annular cavity.

[0042] w2 is the radial dimension of the cross-section of the second-layer annular cavity.

[0043] h2 is the axial dimension of the cross-section of the second-layer annular cavity.

[0044] Ma represents Mach number.

[0045] Pa represents the pressure unit pascal. Specific implementation mode

[0046] The present invention will be described in detail below with reference to the drawings and in combination with embodiments. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0047] In the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and does not require the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the present invention. The terms "connected" and "coupled" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component; it can also be an electrical connection or a signal transmission. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0048] Please refer to Figures 1 to 10 , a broadband ventilation and sound insulation acoustic metasurface structure, comprising a columnar body 1, and an axial through hole 6 is provided in the columnar body 1; N layers of cavities are sequentially arranged in the columnar body 1 along the axial direction, N≥2; the cavities of each layer are isolated from each other; each layer of cavity is provided with an opening facing the through hole 6, and the axial dimension of each layer of cavity is greater than the axial dimension of its opening; the axial cross-sectional dimensions of the cavities of different layers are different from each other.

[0049] Preferably, each layer may be provided with a plurality of unit cavities, the plurality of unit cavities of each layer may be isolated from each other, and are evenly distributed in the circumferential direction, and each unit cavity is provided with an opening facing the through hole 6.

[0050] Preferably, the cross-section of the unit cavity in each layer may be fan-shaped.

[0051] Preferably, the cavities of each layer may be interconnected to form an annular cavity; the annular cavity may be provided with an annular opening facing the through hole 6; the axial cross-sectional dimensions of the annular cavities of each layer may be different from each other.

[0052] Preferably, the axial cross-section of each layer of annular cavity may be circular, elliptical or square.

[0053] Preferably, N = 2; for the annular opening of the first-layer annular cavity 2, its radial dimension is 2-4 mm, and its axial dimension is 8-12 mm; the cross-section of the first-layer annular cavity 2 is square, its radial dimension is 19-21 mm, and its axial dimension is 35-40 mm; for the annular opening of the second-layer annular cavity 3, its radial dimension is 7-9 mm, and its axial dimension is 5-7 mm; the cross-section of the second-layer annular cavity 3 is square, its radial dimension is 13-15 mm, and its axial dimension is 80-84 mm; assuming that the axial direction is perpendicular to the horizontal direction, the second-layer annular cavity 3 is located below the first-layer annular cavity 2; the distance from the center of the annular opening 5 of the second-layer annular cavity to the bottom surface of the columnar body is 16-20 mm.

[0054] Preferably, the columnar body 1 may be a cuboid or a cylinder.

[0055] Preferably, the ratio of the outer diameter to the height of the cylinder can be 1.2 to 2, and the ratio of the diameter of the through hole 6 in the cylinder to the height can be 0.1 to 0.25.

[0056] The present invention also provides a method for manufacturing the above-mentioned broadband ventilation and sound insulation acoustic metasurface structure, which is manufactured by a 3D printing method. The 3D printing material is metal powder, alloy powder, metal matrix composite material or hard plastic powder.

[0057] The metal powder materials include metal powders such as silver, copper, aluminum, and titanium. These powders can be prepared by methods such as fused deposition, electron beam melting, and electron beam melting spraying. During the 3D printing process, these metal powders can be melted and deposited on the corresponding mold by scanning with a laser beam to prepare metal parts with certain shapes and sizes.

[0058] The metal matrix composite material is a composite material composed of metal powder and fiber material, and is usually prepared by methods such as powder sintering and fused deposition. These materials have characteristics such as high strength, high toughness, and high wear resistance, and can be used to prepare parts of various shapes and sizes through different forming methods.

[0059] There are many types of 3D printing alloy powder materials, including stainless steel, aluminum alloy, cobalt-chromium alloy, copper alloy, titanium alloy, and nickel alloy, etc. These powder materials need to meet certain requirements, such as fine particle size, narrow particle size distribution, high sphericity, good fluidity, and high loose bulk density, etc., to ensure excellent performance of the printed products. The characteristics of different alloy powders determine their respective suitable application fields. For example, stainless steel powder has high cost performance and good corrosion resistance, and is suitable for producing complex industrial parts; aluminum alloy powder has the characteristics of light weight and high strength, and is suitable for applications with thin walls and complex geometries; titanium alloy powder is widely used in the aerospace field and can help optimize product design and achieve lightweight production.

[0060] One of the most commonly used materials in 3D printing is plastic materials. Plastic materials are usually used in the form of powder or liquid, and then melted and solidified to produce the required shape. Common plastic materials include polyamide (PA), polylactic acid (PLA), polycarbonate (PC), polyvinyl alcohol (PVA), etc. These materials have the characteristics of being light, cheap, and easy to process, and are widely used in 3D printing. Plastic materials are widely used in manufacturing models, prototypes, parts, etc.

[0061] The present invention also provides an application of the above-mentioned broadband ventilation and sound insulation acoustic metasurface structure, which is used to construct a building structure that is both ventilated and noise-reducing.

[0062] The broadband ventilation and sound insulation acoustic metasurface structure of the present invention can be made into building material units. For example, it can be made into a square column and used as a building block to construct a partition wall that provides ventilation and noise reduction. It can also be made into a cylinder and embedded in the partition wall.

[0063] The following further illustrates the structure and working principle of the present invention with a preferred embodiment of the present invention:

[0064] Please refer to Figures 1 to 3 , a broadband ventilation and sound insulation acoustic metasurface structure, including a columnar body 1, and an axial central through hole 6 is provided in the columnar body 1; N layers of cavities are sequentially provided in the columnar body 1 along the axial direction, N = 2; each layer of cavities is isolated from each other. The radial and axial dimensions of each layer of cavities are correspondingly larger than the radial and axial dimensions of its opening.

[0065] The columnar body 1 is a cylinder. The cavities of each layer communicate with each other to form an annular cavity; the annular cavity is provided with an annular opening facing the through hole 6; the axial cross-sectional dimensions of each layer of annular cavities are different.

[0066] The broadband ventilation and sound insulation acoustic metasurface structure is integrally manufactured by using a 3D printing method, and the 3D printing material is alloy powder or hard plastic powder.

[0067] The broadband ventilation and sound insulation acoustic metasurface structure is equivalent to embedding two layers of annular cavities inside the cylinder wall with a through hole 6. The two layers of annular cavities are provided with annular openings facing the through hole 6. The axial dimension of each layer of cavity is larger than the axial dimension of its opening; the radial dimension of each layer of cavity is larger than the radial dimension of its opening; from the axial cross-section, the annular opening is equivalent to the neck of the annular cavity.

[0068] Introducing gas into a relatively thin-opening container can be called Helmholtz resonance. When gas is introduced into the two layers of annular cavities, the annular cavities can be called Helmholtz resonance cavities. Through the rectangular neck connected to the through hole 6 inside the cylinder, the air flow entering the through hole 6 inside the cylinder flows into the two layers of annular cavities, and the overall structure of the cylinder is similar to the Fabry - Pérot cavity structure.

[0069] The axial cross-section of the two layers of annular cavities is square. Each Helmholtz resonance cavity is composed of a rectangular neck and a rectangular closed cavity, and one side of the neck is connected to the through hole 6 of the cylinder. The Helmholtz resonance cavities rotate 360° around the cylinder axis to form two side branch pipes of the metasurface structure.

[0070] The outer diameter of the cylinder is 100 mm, the height of the cylinder is 150 mm, the diameter of the through hole 6 inside the cylinder is 48 mm. The height of the through hole 6 inside the cylinder is 150 mm. The wall thickness of the cylinder is 26 mm.

[0071] Let w be the wall thickness of the cylinder, w = 26 mm; let h be the height of the cylinder, h = 150 mm; let d1 be the outer diameter of the cylinder, d1 = 100 mm; let d2 be the inner diameter of the through-hole 6 of the cylinder, d2 = 48 mm.

[0072] Let r1 be the outer radius of the cylinder, r1 = 1 / 2×Φ1 = 50 mm; let r2 be the radius of the through-hole 6 of the cylinder, r2 = 1 / 2×Φ2 = 24 mm.

[0073] Let a1 be the radial dimension of the annular opening 4 of the first-layer annular cavity, a1 = 2 mm; let b1 be the axial dimension of the annular opening 4 of the first-layer annular cavity, b1 = 10 mm; let w1 be the radial dimension of the cross-section of the first-layer annular cavity 2, w1 = 19 mm; let h1 be the axial dimension of the cross-section of the first-layer annular cavity 2, h1 = 37 mm; let a2 be the radial dimension of the annular opening 5 of the second-layer annular cavity, a2 = 8 mm; let b2 be the axial dimension of the annular opening 5 of the second-layer annular cavity; let w2 be the radial dimension of the cross-section of the second-layer annular cavity 3, w2 = 13 mm; let h2 be the axial dimension of the cross-section of the second-layer annular cavity 3, h2 = 84 mm.

[0074] Let the axial direction be perpendicular to the horizontal direction, and the second-layer annular cavity 3 is located below the first-layer annular cavity 2; the distance between the center of the annular opening 5 of the second-layer annular cavity and the bottom surface of the columnar body is 18.5 mm.

[0075] The present invention uses an integrated 3D printing method to fabricate a reflective metasurface structure, achieving efficient sound insulation for broadband noise in the range of 673 Hz to 2468 Hz while ensuring efficient ventilation.

[0076] The working principle of the present invention is as follows:

[0077] The Fabry- cavity (Fabry-Perot resonator) structure of the present invention is a cylinder with a central circular air cavity channel, and the entire structure is centrosymmetrically arranged with the axis of the cylinder as the center.

[0078] The dimensions of the Helmholtz resonators of each layer and the dimensions of their openings are different. In this case, the radial and axial dimensions of the annular cavity and its annular opening affect the resonance wavelength and the sound wave propagation path.

[0079] By adjusting the radial and axial dimensions of the cavities and their openings of each layer, the noise reduction treatment for sound waves of different wavelengths or frequencies can be adjusted.

[0080] When a noise source generates within a specific broadband frequency range, sound waves pass through the through-hole 6 of the cylinder from the bottom or the top. When air and sound waves pass through the through-hole 6, the sound waves will cause the air to vibrate during propagation, thereby generating an air current. The air current entering the through-hole 6 inside the cylinder flows into the two-layer annular cavity. The sound waves also propagate along with the air current. When the sound waves encounter obstacles such as the cavity wall, reflection, refraction, and diffraction will occur, resulting in the bending of the propagation path.

[0081] The through-hole 6 inside the cylinder can maintain a relatively large air current channel. The annular cavity increases the length of the air current channel and causes the sound waves to reflect, refract, and diffract, resulting in the bending of the propagation path, and has a good sound absorption effect.

[0082] The present invention generates an acoustic resonance effect, effectively attenuates and isolates the noise within this frequency band without significantly affecting the air flow and ventilation performance, achieving the effect of broadband noise control.

[0083] The preferred embodiment of the present invention can achieve a transmission loss continuously exceeding 10 dB within the frequency range of 673 to 2468 Hz, and the average sound transmission loss reaches 23.8 dB, ensuring efficient suppression of broadband noise.

[0084] When air passes through the through-hole 6, the air current entering the through-hole 6 inside the cylinder flows into the two-layer annular cavity. For a Fabry– resonant cavity with an inner diameter of 50 mm and an outer diameter of 100 mm, its frequency response characteristics usually show a periodic distribution of sound loss.

[0085] Figure 4 is a schematic diagram of the transmission loss of a broadband ventilation and sound insulation acoustic metasurface structure of the present invention compared with a pure Fabry- cavity of the same size. The solid line represents the transmission loss of the structure of the present invention, and the dotted line represents the transmission loss of the pure Fabry- cavity structure.

[0086] From Figure 4 the dotted line in it, it can be clearly seen that the transmission loss shows obvious periodic fluctuations with the frequency, and this phenomenon directly reflects the effect of the standing wave interference in the Fabry– cavity. However, the insufficient sound loss at the periodic troughs will lead to a significant decline in the overall sound insulation performance of the system. To achieve the design goal of broadband sound insulation, it is necessary to optimize and adjust the structure of these low-loss frequency bands to enhance the sound energy dissipation ability and achieve a more balanced broadband sound insulation effect. In the present invention, for the first two "trough" frequency bands of sound loss, side branch pipes are opened using Helmholtz resonators and are arranged inside the Fabry– cavity, aiming to improve the sound loss at the troughs and thus significantly enhance the sound insulation performance of the system.

[0087] Specifically, two layers of annular cavities are arranged inside the Fabry– cavity, and the two layers of annular cavities form a Helmholtz resonance cavity. The neck of each Helmholtz resonance cavity is directly connected to the through-hole 6 of the Fabry– cavity, ensuring that when sound waves pass through the cavity, the energy can be effectively dissipated and converted into heat energy, thereby significantly reducing the impact of periodic valleys on the transmission loss.

[0088] Through the special structure of the Helmholtz resonance cavity, the present invention enhances the absorption and dissipation ability of sound waves in the low-loss frequency band. In the original frequency response of the Fabry– cavity, the transmission loss of sound waves in these two low-loss frequency bands (i.e., valleys) is relatively low, which easily leads to a decrease in the sound insulation effect. By setting Helmholtz resonance cavities in these two frequency bands, these valley regions are optimized specifically to ensure that sound energy can be effectively attenuated in these frequency bands.

[0089] From Figure 4 it can be observed that within the wide frequency range from 673 Hz to 2468 Hz, the transmission loss of the present invention continuously exceeds 10 dB, and the average sound transmission loss reaches 23.8 dB, significantly improving the wide-frequency sound insulation effect of the entire structure. This design not only improves the periodic valley problem of the traditional Fabry– cavity, but also provides excellent sound insulation performance on the premise of ensuring good ventilation function, fully meeting the dual requirements of modern architecture and industrial fields for ventilation and noise control.

[0090] Figure 5 is a schematic diagram of the energy coefficient of a wide-frequency ventilation and sound insulation acoustic metasurface structure of the present invention. From Figure 5 it can be seen that within the wide frequency range from 673 Hz to 2468 Hz, the structure mainly achieves broadband sound insulation by reflection.

[0091] Figure 6 is a schematic diagram of the experimental results and simulation results of the transmission loss of a wide-frequency ventilation and sound insulation acoustic metasurface structure of the present invention. From Figure 6 it can be seen that through simulation and experimental verification, the structure of the present invention exhibits excellent acoustic performance within the predetermined frequency range. Further experiments prove the sound insulation effect of the structure of the present invention in practical applications, verify the accuracy of the simulation prediction, and confirm the effectiveness of optimizing the low-frequency sound insulation performance through the Helmholtz resonance cavity. The consistency between the simulation and experimental results fully demonstrates the feasibility and superiority of the present invention in the field of wide-frequency sound insulation.

[0092] Figure 7 and Figure 8 are schematic diagrams of the sound pressure attenuation effect of the wide-frequency ventilation and sound insulation of the metasurface provided by the embodiments of the present invention. Figure 7It shows the attenuation of the sound wave vertically incident from the bottom when the sound wave frequency is 892 Hz, while Figure 8 corresponds to the case where the sound wave frequency is 1816 Hz. These two frequencies respectively correspond to the two transmission loss peaks of the structure.

[0093] Figure 9 It is a schematic diagram of the average flow velocity result under the condition of considering air flow when the incident sound wave frequency is 892 Hz and the Mach number (Ma) is 0.1 in the embodiment of the present invention. By simulating the influence of air flow, the mutual relationship between the flow velocity and the sound wave transmission process is analyzed, and the sound insulation ability of the structure in a dynamic environment is further simulated.

[0094] Figure 10 It is a schematic diagram of the transmission loss results of an embodiment of a broadband ventilation sound insulation acoustic metasurface structure of the present invention at different Mach numbers (Ma). By adjusting the Mach number, the sound insulation effects of the metasurface structure under different flow velocity conditions are respectively investigated. Even under different flow conditions, the structure can still maintain good sound insulation performance.

[0095] The above-described embodiments are only used to illustrate the technical ideas and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The patent scope of the present invention cannot be limited only by these embodiments, that is, any equivalent changes or modifications made according to the spirit disclosed in the present invention still fall within the patent scope of the present invention.

Claims

1. A broadband ventilation sound insulation acoustic metasurface structure, characterized in that: It includes a columnar body, in which an axial through hole is arranged; N layers of cavities are arranged in sequence along the axial direction of the columnar body, N ≥ 2; each layer of cavities is isolated from each other; each layer of cavities has an opening facing the through hole, and the axial size of each layer of cavities is larger than the axial size of its opening; the sizes of the axial sections of cavities in different layers are different.

2. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 1, characterized in that: Each layer is provided with a plurality of unit cavities, the plurality of unit cavities in each layer are isolated from each other and evenly distributed along the circumference, and each unit cavity is provided with an opening facing the through hole.

3. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 2, characterized in that: The cross section of the unit cavity of each layer is fan-shaped.

4. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 1, characterized in that: The cavities of each layer are interconnected to form an annular cavity; the annular cavity has an annular opening facing the through hole; and the sizes of the axial sections of the annular cavities of each layer are different.

5. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 4, characterized in that: The axial cross-section of each layer of the annular cavity is circular, elliptical or square.

6. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 5, characterized in that: N=2; the annular opening of the first layer of annular cavity has a radial dimension of 2-4mm and an axial dimension of 8-12mm; the cross-section of the first layer of annular cavity is square, with a radial dimension of 19-21mm and an axial dimension of 35-40mm; the annular opening of the second layer of annular cavity has a radial dimension of 7-9mm and an axial dimension of 5-7mm; the cross-section of the second layer of annular cavity is square, with a radial dimension of 13-15mm and an axial dimension of 80-84mm; assuming that the axial direction is perpendicular to the horizontal direction, the second layer of annular cavity is located at the lower part of the first layer of annular cavity; the distance between the center of the annular opening of the second layer of annular cavity and the bottom surface of the columnar body is 16-20mm.

7. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 1, characterized in that: The columnar body is a rectangular parallelepiped or a cylinder.

8. The broadband ventilation and sound insulation acoustic metasurface structure according to claim 7, characterized in that: The ratio of the outer diameter to the height of the cylinder is 1.2 to 2, and the ratio of the diameter to the height of the through hole in the cylinder is 0.1 to 0.

25.

9. A method for manufacturing a broadband ventilation sound insulation acoustic metasurface structure according to any one of claims 1 to 8, characterized in that: It is made by 3D printing method, and the 3D printing material is metal powder, alloy powder or hard plastic powder.

10. An application of the broadband ventilation sound insulation acoustic metasurface structure according to any one of claims 1 to 8, characterized in that: Used to create building structures that are both ventilated and noise-reducing.

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