Acoustic metamaterial unit cell structure and unit cell assembly
By designing the acoustic metamaterial single cell structure and using subwavelength-scale microstructures to modulate the sound waves, the problems of high noise control costs and large space occupation in the prior art are solved, and efficient and low-cost wide-band noise reduction effect is achieved.
Patent Information
- Application Number
- CN202510375846.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-06-27
AI Technical Summary
The prior art relies on increasing the thickness of the sound insulation structure in noise control, resulting in large space occupancy and high cost.
An acoustic metamaterial single cell structure is designed, using subwavelength-scale microstructures, including nested connected first Helmholtz resonance cavity and second Helmholtz resonance cavity, through which modulation and noise reduction of sound waves are achieved.
It realizes effective noise reduction in scenarios with limited space, with low noise reduction costs, and achieves wide frequency noise reduction effect by combining multiple single-cell structures, covering a wider frequency range.
Smart Images
Figure CN120220635A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of acoustic materials for noise control, and particularly to a single-cell structure and a combined single-cell body of acoustic metamaterials. Background Art
[0002] In daily life, environmental noise brings many adverse effects. In order to reduce or eliminate the adverse effects of noise, we need to control the noise. According to the generation, propagation, and reception of noise, we can suppress noise at the sound source, control noise in the sound propagation path, or control it at the sound reception point. Among these three control methods, controlling noise in the sound propagation path is the most common technique. Currently, the main method for controlling noise is to increase the thickness of the sound insulation structure, but this method often requires a large amount of space and huge costs. Summary of the Invention
[0003] The purpose of the present invention is to provide a single-cell structure and a combined single-cell body of acoustic metamaterials to solve the problems existing in the above-mentioned prior art. The single-cell structure is small in size and easy to combine, can effectively reduce noise at different frequencies, and has a low noise reduction cost.
[0004] To achieve the above purpose, the present invention provides the following solutions:
[0005] The present invention provides a single-cell structure of acoustic metamaterials. The single-cell structure of acoustic metamaterials is a sub-wavelength structure, including a first Helmholtz resonance cavity and a second Helmholtz resonance cavity connected in a nested manner.
[0006] The first Helmholtz resonance cavity includes a first cylindrical cavity. One end of the first cylindrical cavity is recessed inward to form a frustum-shaped embedding groove. An outlet is provided in the middle of the other end. The frustum-shaped embedding groove and the first cylindrical cavity are coaxial. The diameter of the groove opening of the frustum-shaped embedding groove is equal to the diameter of the first cylindrical cavity. The diameter of the groove bottom of the frustum-shaped embedding groove is smaller than the diameter of the groove opening. There is a gap between the groove bottom of the frustum-shaped embedding groove and the outlet end face of the first cylindrical cavity.
[0007] The second Helmholtz resonance cavity includes a cylindrical section and a frustum section connected by a coaxial line. One end of the cylindrical section is connected to the large end of the frustum section, and an inlet is provided in the middle of the other end face. The diameter of the cylindrical section is smaller than that of the first cylindrical cavity and is equal to the diameter of the large end of the frustum section. The height of the cylindrical section is smaller than that of the first cylindrical cavity. The frustum section is embedded in the frustum-shaped embedding groove and they are coaxially arranged. The small end of the frustum section is fixed to the bottom of the frustum-shaped embedding groove. The diameter of the small end of the frustum section is not less than the diameters of the outlet and the inlet. The diameter of the small end of the frustum section is smaller than the diameter of the bottom of the frustum-shaped embedding groove. The small end of the frustum section is an open end. A through hole with the same size and coaxial with the opening of the small end of the frustum section is provided at the bottom of the frustum-shaped embedding groove. The height of the frustum section is greater than the depth of the frustum-shaped embedding groove.
[0008] Preferably, a circular partition is provided inside the first cylindrical cavity. The circular partition is arranged on the side of the bottom of the frustum-shaped embedding groove facing away from the groove opening. The circular partition is coaxially arranged with the frustum-shaped embedding groove. One end of the circular partition is fixedly connected to the bottom of the frustum-shaped embedding groove, and the other end is fixed to the end face of the outlet of the first cylindrical cavity. A plurality of micropores are evenly distributed along the circumferential direction on the circular partition.
[0009] Preferably, the diameter of the first cylindrical cavity is D, 50 mm ≤ D ≤ 200 mm, and the height is L, 15 mm ≤ L ≤ 75 mm; the diameter of the cylindrical section is D1, 49 mm ≤ D1 ≤ 199 mm, and the height is L1, 1 mm ≤ L1 ≤ 30 mm.
[0010] Preferably, the difference between the height of the frustum section and the depth of the frustum-shaped embedding groove is L2, 2 mm ≤ L2 ≤ 8 mm; the distance from the bottom of the frustum-shaped embedding groove to the end face of the outlet of the first cylindrical cavity is L3, 4 mm ≤ L3 ≤ 10 mm.
[0011] Preferably, the diameter of the small end of the frustum section is T, 20 mm ≤ T ≤ 100 mm; the difference between the radius of the bottom of the frustum-shaped embedding groove and the radius of the small end of the frustum section is T1, 2 mm ≤ T1 ≤ 5 mm.
[0012] Preferably, the diameters of the outlet and the inlet are equal.
[0013] Preferably, the radius of the micropore is R 孔 , 0.5 mm ≤ R 孔 ≤ 2 mm, and the perforation rate of the circular partition is 2% - 5%.
[0014] Preferably, the outlet is connected with an outlet pipe, and the height of the outlet pipe is L4, 1 mm ≤ L4 ≤ 10 mm.
[0015] Preferably, the first Helmholtz resonance cavity and the second Helmholtz resonance cavity are of an integrally formed structure.
[0016] The present invention also provides an acoustic metamaterial unit cell assembly, which is a combination of any one, two or more of the above-mentioned acoustic metamaterial unit cell structures, and each of the acoustic metamaterial unit cell structures is arranged periodically.
[0017] The present invention has achieved the following technical effects compared with the prior art:
[0018] The acoustic metamaterial unit cell structure provided by the present invention realizes the modulation of sound waves through the microstructure design at the sub-wavelength scale (i.e., the structural size is much smaller than the wavelength of sound wave propagation). Compared with the traditional sound-absorbing material, the size of the sound-absorbing metamaterial unit cell structure is smaller, making it easier to achieve the noise reduction effect in scenarios with limited space. At the same time, when multiple sound-absorbing metamaterial unit cell structures are combined, that is, the acoustic metamaterial unit cell assembly provided by the present invention, the effect of broadband noise reduction can be achieved, which can cover a wider frequency range, thereby more effectively reducing the noise of different frequencies. Since the size of the sound-absorbing metamaterial unit cell structure is small and easy to combine, it can be flexibly designed according to actual needs and space conditions, and the noise reduction cost is low. Description of the Drawings
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0020] Figure 1 It is a schematic diagram of the acoustic metamaterial unit cell structure in Embodiment 1 of the present invention;
[0021] Figure 2 It is a schematic diagram of the size of the acoustic metamaterial unit cell structure in Embodiment 1 of the present invention;
[0022] Figure 3 It is a curve graph of the sound wave signal transmission loss of the unit cell structure in Embodiment 1 of the present invention;
[0023] Figure 4 It is a schematic diagram of the acoustic metamaterial unit cell structure in Embodiment 2 of the present invention;
[0024] Figure 5 It is a schematic diagram of the size of the acoustic metamaterial unit cell structure in Embodiment 2 of the present invention;
[0025] Figure 6It is the sound wave signal transmission loss curve of the single-cell structure in the second embodiment of the present invention;
[0026] Figure 7 It is the sound wave signal transmission loss curve of the single-cell assembly in the third embodiment of the present invention.
[0027] In the figure: 1 - the first Helmholtz resonance cavity, 2 - the second Helmholtz resonance cavity, 3 - the first cylindrical cavity, 4 - the frustum-shaped embedding groove, 5 - the outlet, 6 - the cylindrical section, 7 - the frustum section, 8 - the inlet, 9 - the circular partition, 10 - the micropores, 11 - the outlet pipe, 12 - the inlet pipe. Specific embodiments
[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0029] The purpose of the present invention is to provide an acoustic metamaterial single-cell structure and a single-cell assembly to solve the problems existing in the prior art. The single-cell structure is small in size and easy to combine, can effectively reduce noise at different frequencies, and has a low noise reduction cost.
[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0031] Embodiment 1
[0032] As Figure 1 - Figure 2 shown, this embodiment provides an acoustic metamaterial single-cell structure. The acoustic metamaterial single-cell structure is a sub-wavelength structure, including a first Helmholtz resonance cavity 1 and a second Helmholtz resonance cavity 2 connected in a nested manner;
[0033] The first Helmholtz resonance cavity 1 includes a first cylindrical cavity 3. One end of the first cylindrical cavity 3 is recessed inward to form a frustum-shaped embedding groove 4, and an outlet 5 is provided in the middle of the other end. The frustum-shaped embedding groove 4 and the first cylindrical cavity 3 are coaxial. The diameter of the groove opening of the frustum-shaped embedding groove 4 is equal to the diameter of the first cylindrical cavity 3. The diameter of the groove bottom of the frustum-shaped embedding groove 4 is smaller than the diameter of the groove opening. There is a gap between the groove bottom of the frustum-shaped embedding groove 4 and the outlet end face of the first cylindrical cavity 3;
[0034] The second Helmholtz resonance cavity 2 includes a cylindrical section 6 and a frustum section 7 connected by a coaxial line. One end of the cylindrical section 6 is connected to the large end of the frustum section 7, and an inlet 8 is provided in the middle of the other end face. The diameter of the cylindrical section 6 is smaller than that of the first cylindrical cavity 3 and is equal to the diameter of the large end of the frustum section 7. The height of the cylindrical section 6 is smaller than that of the first cylindrical cavity 3. The frustum section 7 is embedded in the frustum-shaped embedding groove 4 and they are coaxially arranged. The small end of the frustum section 7 is fixed to the bottom of the frustum-shaped embedding groove 4. The diameter of the small end of the frustum section 7 is not less than the diameters of the outlet 5 and the inlet 8. The diameter of the small end of the frustum section 7 is smaller than the diameter of the bottom of the frustum-shaped embedding groove 4. The small end of the frustum section 7 is an open end. A through hole with the same size and coaxial with the opening of the small end of the frustum section 7 is provided at the bottom of the frustum-shaped embedding groove 4. The height of the frustum section 7 is greater than the depth of the frustum-shaped embedding groove 4.
[0035] The acoustic metamaterial unit cell structure provided in this embodiment realizes the modulation of sound waves through the microstructure design at the sub-wavelength scale (i.e., the structural size is much smaller than the wavelength of sound wave propagation) and generates extraordinary physical effects. The extraordinary physical effects of acoustic metamaterials are mainly reflected in that through the artificially designed periodic or aperiodic geometric structures, a series of acoustic characteristics that are not possessed by conventional materials are realized at the sub-wavelength scale (i.e., one-tenth of the wavelength). For example, acoustic metamaterials can generate low-frequency bandgaps of sound waves, that is, within this frequency range, the propagation of sound waves is effectively suppressed, forming a sound wave stopband. This characteristic has important application values in the fields of noise control, sound wave filtering, etc. Compared with traditional sound-absorbing materials, the size of the sound-absorbing metamaterial unit cell structure is smaller, making it easier to achieve noise reduction effects in scenarios with limited space. At the same time, when multiple sound-absorbing metamaterial unit cell structures are combined, that is, the acoustic metamaterial unit cell combination, the effect of broadband noise reduction can be achieved, which can cover a wider frequency range, thereby more effectively reducing noises of different frequencies. Due to the small size and easy combination of the sound-absorbing metamaterial unit cell structure, it can be flexibly designed according to actual needs and space conditions, and the noise reduction cost is low.
[0036] Among them, the diameter of the first cylindrical cavity 3 is D, 50mm ≤ D ≤ 200mm, and the height is L, 15mm ≤ L ≤ 75mm; the diameter of the cylindrical section 6 is D1, 49mm ≤ D1 ≤ 199mm, and the height is L1, 1mm ≤ L1 ≤ 30mm. The difference between the height of the frustum section 7 and the depth of the frustum-shaped embedding groove 4 is L2, 2mm ≤ L2 ≤ 8mm; the distance from the bottom of the frustum-shaped embedding groove 4 to the outlet end face of the first cylindrical cavity 3 is L3, 4mm ≤ L3 ≤ 10mm. The diameter of the small end of the frustum section 7 is T, 20mm ≤ T ≤ 100mm; the difference between the radius of the bottom of the frustum-shaped embedding groove 4 and the radius of the small end of the frustum section 7 is T1, 2mm ≤ T1 ≤ 5mm. The diameters of the outlet 5 and the inlet 8 are equal, both are C, and C ≤ T.
[0037] The outlet 5 is connected to an outlet pipe 11, and the height of the outlet pipe 11 is L4, where 1 mm ≤ L4 ≤ 10 mm. The inlet 8 is connected to an inlet pipe 12, and the height of the inlet pipe 12 is equal to that of the outlet pipe 11.
[0038] The first Helmholtz resonance cavity 1 and the second Helmholtz resonance cavity 2 are of an integrally formed structure.
[0039] For the acoustic metamaterial unit cell structure provided in this embodiment, the air inlet and outlet directions are as Figure 1 shown by the arrow directions.
[0040] The acoustic metamaterial unit cell structure provided in this embodiment has a compact structure and a thin overall thickness. By changing the size parameters of the unit cell structure, effective sound absorption in the target frequency band or at the frequency point can be achieved. Through the combination of unit cells of different sizes, good noise reduction effects can be obtained for medium and low frequency (500 - 3000 Hz) noise.
[0041] Specifically, in this embodiment, when D = 147.6 mm, D1 = 143.6 mm, L = 25 mm, L1 = 15 mm, L2 = 5 mm, L3 = 5 mm, T = 63 mm, T1 = 2 mm, C = 57 mm, and L4 = 5 mm, the sound wave signal transmission loss curve of the acoustic metamaterial unit cell structure is as Figure 3 shown. The transmission loss curve graph can describe the response of the sound wave signal at different frequencies. In Figure 3 it, the abscissa represents the frequency of the sound wave signal, with the unit of Hertz (Hz), and the ordinate represents the attenuation of the sound wave signal, and the value of the transmission loss can be expressed in decibels (dB). At some frequency points, the transmission loss is relatively high, which means that the sound waves of these frequencies suffer greater attenuation when passing through the acoustic metamaterial unit cell structure. While at other frequency points, the transmission loss is relatively low, indicating that the sound waves of these frequencies are more likely to penetrate the acoustic metamaterial unit cell structure. It can be seen from Figure 3 that near 1020 Hz and 2120 Hz, the transmission loss of the sound wave through the acoustic metamaterial unit cell structure is as high as 50 dB, and the attenuation effect of the sound wave is obvious in the vicinity. And in the frequency range between 1020 Hz and 2120 Hz, the transmission loss of the sound wave through the acoustic metamaterial unit cell structure is approximately around 10 dB.
[0042] Embodiment Two
[0043] As Figure 4 - Figure 5As shown in the figure, this embodiment provides a unit cell structure of acoustic metamaterials. Different from the first embodiment, a circular partition 9 is further provided inside the first cylindrical cavity 3. The circular partition 9 is arranged on the side of the bottom of the frustum-shaped embedding groove 4 facing away from the notch. The circular partition 9 is coaxially arranged with the frustum-shaped embedding groove 4. One end of the circular partition 9 is fixedly connected to the bottom of the frustum-shaped embedding groove 4, and the other end is fixed to the outlet end face of the first cylindrical cavity 3. A plurality of micropores 10 are evenly distributed along the circumferential direction on the circular partition 9.
[0044] The radius of the micropore 10 is R 孔 , 0.5mm ≤ R 孔 ≤ 2mm, and the perforation rate of the circular partition 9 is 2% - 5%.
[0045] The micro-perforated structure can effectively reduce high-frequency noise. The principle of micro-perforation is based on the attenuation and scattering effects that occur when sound waves pass through small holes. When sound waves penetrate into tiny pores, since the size of the pores is much smaller than the sound wave wavelength, the sound waves will interact with the pore edges, resulting in the attenuation of the sound waves. Due to the existence of the pores, the propagation path of the sound waves will also change, resulting in the generation of scattering effects. For high-frequency sound waves, the attenuation and scattering effects are more obvious. The unit cell structure of acoustic metamaterials with micropores 10 in this embodiment has a good noise reduction effect for specific frequencies. The unit cell structures of acoustic metamaterials with micropores 10 of different sizes have good noise reduction effects for noises at different frequency points. By arranging and combining the unit cell structures of acoustic metamaterials with micropores 10 of different sizes, a good noise reduction effect can be achieved in the medium and high frequency (3000 - 6000Hz) wide frequency band.
[0046] Specifically, in this embodiment, when D = 90mm, D1 = 86mm, L = 20mm, L1 = 1mm, L2 = 5mm, L3 = 5mm, T = 63mm, T1 = 2mm, R 孔 = 0.75mm, the perforation rate = 2%, C = 63mm, L4 = 5mm, the transmission loss curve of the unit cell structure is as Figure 6 shown. It can be seen from Figure 6 that near 6620Hz, the transmission loss of the sound wave through the unit cell structure of acoustic metamaterials can reach 35dB, indicating that near 6620Hz, the attenuation effect of the sound wave after passing through the unit cell structure is more obvious. Generally, for the convenience of arranging and combining the unit cell structures of acoustic metamaterials of different sizes, and considering the diameter of the connecting inlet and outlet pipes, usually the C value in each unit cell structure of acoustic metamaterials takes the same value, and the L4 value takes the same value.
[0047] Embodiment Three
[0048] This embodiment provides an acoustic metamaterial unit cell assembly, which includes a plurality of acoustic metamaterial unit cell structures described in Embodiment 1 and Embodiment 2, and each acoustic metamaterial unit cell structure is arranged periodically. Each acoustic metamaterial unit cell structure has different parameter values. It can effectively broaden the frequency range of noise reduction and achieve a better noise reduction effect. It can also perform single-frequency or multi-frequency sound absorption according to the frequency of sound absorption elimination.
[0049] For example, to achieve the goal of a noise reduction of more than 20 dB in the frequency range of 1000 - 5000 Hz, the acoustic metamaterial unit cells of different sizes in Embodiment 1 and Embodiment 2 are arranged periodically, and the sound absorption performance of the unit cell assembly is as Figure 7 shown. In the frequency range of 1000 - 5000 Hz, the transmission loss of sound waves through the unit cell assembly reaches more than 20 dB.
[0050] The acoustic metamaterial unit cell structure provided by the present invention, in practical applications, can be arranged radially along the pipeline. By adjusting the parameters of the unit cell structure, the sound absorption performance of unit cells of different sizes can be achieved. By reasonably controlling the parameters, broadband sound absorption can be achieved, and single-frequency or multi-frequency sound absorption can also be performed according to the frequency of sound absorption elimination.
[0051] For the simplicity of the processing technology, generally, only D, D1, L, L1, and T need to be adjusted for parametric analysis, and the remaining parameters remain unchanged. Of course, all parameters can also be adjusted.
[0052] The acoustic metamaterial unit cell structure provided by the present invention can be made of different materials. Its flexibility in material selection enables the metamaterial unit cell structure and the unit cell assembly to adapt to different working environments and requirements. For example, materials such as rigid plastics, ceramics, and stainless steel can be used to manufacture acoustic metamaterial unit cell structures that meet harsh working environments.
[0053] Specific examples are used in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.
Claims
1. An acoustic metamaterial unit cell structure, characterized in that: The acoustic metamaterial unit cell structure is a sub-wavelength structure, comprising a first Helmholtz resonance cavity and a second Helmholtz resonance cavity that are nested and connected; The first Helmholtz resonance cavity comprises a first cylindrical cavity, one end of the first cylindrical cavity is recessed inward to form a truncated cone-shaped embedding groove, and an outlet is provided in the middle of the other end, the truncated cone-shaped embedding groove is coaxial with the first cylindrical cavity, the notch diameter of the truncated cone-shaped embedding groove is equal to the diameter of the first cylindrical cavity, the bottom diameter of the truncated cone-shaped embedding groove is smaller than the notch diameter, and there is a gap between the bottom of the truncated cone-shaped embedding groove and the outlet end face of the first cylindrical cavity; The second Helmholtz resonance cavity includes a cylindrical section and a truncated cone section which are coaxially connected to each other, one end of the cylindrical section is connected to the large end of the truncated cone section, and an inlet is provided in the middle of the end face of the other end, the diameter of the cylindrical section is smaller than the diameter of the first cylindrical cavity and is equal to the diameter of the large end of the truncated cone section, the height of the cylindrical section is smaller than the height of the first cylindrical cavity, the truncated cone section is embedded in the truncated cone-shaped embedding groove and the two are coaxially arranged, the small end of the truncated cone section is fixed to the bottom of the truncated cone-shaped embedding groove, the diameter of the small end of the truncated cone section is not smaller than the diameter of the outlet and the inlet, the diameter of the small end of the truncated cone section is smaller than the bottom diameter of the truncated cone-shaped embedding groove, the small end of the truncated cone section is an open end, the bottom of the truncated cone-shaped embedding groove is provided with a through hole which is equal to the opening size of the small end of the truncated cone section and is coaxial, and the height of the truncated cone section is greater than the depth of the truncated cone-shaped embedding groove.
2. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: A circular partition is provided inside the first cylindrical cavity, and the circular partition is arranged on the side of the bottom of the truncated cone-shaped embedding groove facing away from the groove mouth. The circular partition is arranged coaxially with the truncated cone-shaped embedding groove, one end of the circular partition is fixedly connected to the bottom of the truncated cone-shaped embedding groove, and the other end is fixed to the outlet end face of the first cylindrical cavity, and a plurality of micropores are evenly distributed on the circular partition along the circumferential direction.
3. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: The diameter of the first cylindrical cavity is D, 50mm≤D≤200mm, and the height is L, 15mm≤L≤75mm; the diameter of the cylindrical section is D1, 49mm≤D1≤199mm, and the height is L1, 1mm≤L1≤30mm.
4. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: The difference between the height of the truncated cone segment and the depth of the truncated cone-shaped engaging groove is L2, 2mm≤L2≤8mm; the distance between the bottom of the truncated cone-shaped engaging groove and the outlet end face of the first cylindrical cavity is L3, 4mm≤L3≤10mm.
5. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: The diameter of the small end of the truncated cone segment is T, 20mm≤T≤100mm; the difference between the groove bottom radius of the truncated cone-shaped engaging groove and the small end radius of the truncated cone segment is T1, 2mm≤T1≤5mm.
6. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: The outlet and the inlet have equal diameters.
7. The acoustic metamaterial unit cell structure according to claim 2, characterized in that: The radius of the micropore is R 孔 , 0.5mm≤R 孔 ≤2mm, and the perforation rate of the circular partition is 2%-5%.
8. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: The outlet is connected to an outlet pipe, and the height of the outlet pipe is L4, 1mm≤L4≤10mm.
9. The acoustic metamaterial unit cell structure according to claim 1, characterized in that: The first Helmholtz resonance cavity and the second Helmholtz resonance cavity are an integrally formed structure.
10. An acoustic metamaterial unit cell assembly, characterized in that: The acoustic metamaterial unit cell assembly is any one, or a combination of two or more of the acoustic metamaterial unit cell structures described in claims 1 to 9, and each of the acoustic metamaterial unit cell structures is arranged periodically.