Plate-cavity coupling resonance acoustic metamaterial unit cell structure containing elastic layer

Abstract

The plate-cavity coupling resonance acoustic metamaterial unit cell structure comprises a resonance plate and a cavity layer, the side portion and one end portion of the cavity layer are closed, the other end of the cavity layer is open, the cavity layer is connected with the resonance plate through the elastic layer, a narrow slit is formed in the resonance plate, and the elastic layer is arranged in the narrow slit. A suspension part capable of freely vibrating is formed in a hollow-out and enclosed area of the resonance plate by the narrow slits; the problems that an existing plate-cavity coupling resonance sound insulation structure is limited in frequency selection and the structure size is complex to adjust are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sound insulation structures, and particularly to a plate-cavity coupled resonance acoustic metamaterial unit cell structure containing an elastic layer. Background Art

[0002] In engineering practice, in addition to medium and high frequency noise, low frequency noise is also a problem that cannot be ignored. Compared with medium and high frequency noise, the control technology for low frequency noise is more challenging. Generally, the starting frequency of low frequency noise is set at 20 Hz internationally, and sounds below this frequency are classified as infrasound. Nevertheless, when the sound pressure level of infrasound is relatively high, people can still feel these sounds below 20 Hz. Since the impact of infrasound on human health is relatively small, the research on noise isolation in this frequency band is not extensive. However, in actual engineering applications, the situation where infrasound affects the human body does exist. Therefore, how to effectively control low frequency noise in the infrasound range has become a scientific research problem that urgently needs to be solved.

[0003] Currently, numerous sound insulation and absorption structures developed based on resonance effects have emerged, showing more advantages compared with traditional sound insulation and absorption structures. In particular, these resonance-based sound insulation structures perform well in dealing with low frequency noise, while traditional sound insulation materials focus more on suppressing medium and high frequency noise. Compared with traditional sound insulation structures, resonance sound insulation structures can more precisely control sound waves of specific frequencies. According to the mass law, when improving the sound insulation effect of traditional sound insulation structures, it is often necessary to significantly increase the size and thickness of the structure, which not only makes the structure for controlling low frequency noise too large, but also increases the cost accordingly. In contrast, the sound insulation structures designed based on the resonance principle stand out with their characteristics of simple structure, thinness, lightness and low weight.

[0004] Currently on the market, the sound insulation structures designed based on the local resonance mechanism mainly include thin-film acoustic metamaterials, Helmholtz resonators, and sound cavity coupled sound insulation structures, etc. Thin-film acoustic metamaterials are structures that can precisely control specific sound waves through artificial microstructural design, mainly composed of a thin film and an additional mass block, as Figure 1 shown, where A represents the additional mass block, B represents the thin film, and C represents the support structure. Its sound insulation mechanism is that when the sound wave frequency approaches the resonance frequency of the metamaterial structural unit, a strong resonance phenomenon will occur, triggering the local resonance effect, achieving negative equivalent mass density or negative equivalent stiffness, and thus improving the sound insulation effect. However, the sound insulation efficiency of this structure is usually limited to a relatively narrow frequency band. In addition, the design of such precise microstructures has high requirements for manufacturing technology, especially for the precise control of the thin film tension, and the thin film structure is more fragile in actual applications than other sound insulation structures. These factors may all increase the cost.

[0005] A Helmholtz resonator is a traditional acoustic device, which generally consists of a closed cavity communicating with the external environment through a small hole or a slender pipe, as Figure 2 shown. Its sound absorption mechanism mainly relies on the resonance effect. Sound waves enter the interior of the resonator through the pipe. When the frequency of the sound waves is the same as the resonance frequency of the resonator, it will cause violent oscillations of the air in the pipe, and then convert the sound energy into vibration energy, and convert the sound energy into heat energy under the friction and viscosity of the pipe. By adjusting the geometric parameters such as the diameter d, length L of the pipe and the volume V of the cavity, the resonance frequency of the resonator can be adjusted. However, in order to absorb low-frequency noise, it is often necessary to increase the volume of the resonator, which may lead to too large structural dimensions. At the same time, in order to achieve the expected sound absorption effect, the Helmholtz resonator requires delicate design and manufacturing, which may involve complex technological processes, thus increasing the cost.

[0006] In addition, there is also a plate-cavity coupled resonance sound insulation structure, which consists of a cuboid structure. The structure is provided with an open cavity at one end, and a flexible thin plate is closely attached to the open end. The thin plate is distributed with a plurality of uniformly distributed slender cracks, jointly forming a plate-cavity coupled system. By adjusting the length, width and their distribution of these cracks, sound waves of different frequencies can be blocked, thereby improving the sound insulation effect. Arranging multiple plate-cavity coupled structures in a periodic manner forms an array plate-cavity coupled structure, as Figure 3 shown, where a represents the cavity, b represents the flexible thin plate, and c represents the crack. When the frequency of the sound wave approaches the resonance frequency of the structure, the sound wave will continuously reflect and refract inside the cavity after entering, consuming the sound energy. However, this structure also has some limitations. For example, it is difficult to deal with the noise control in the infrasound frequency band only by processing the plate-cavity coupled structure on the existing plate, that is, the frequency selectivity of the existing structure is not strong. At the same time, when adjusting the plate-cavity coupled structure for specific frequency noise, the size adjustment is relatively complex, the processing difficulty increases, and the cost may increase. Summary of the Invention

[0007] The purpose of the present invention is to overcome the above deficiencies and provide a plate-cavity coupled resonance acoustic metamaterial unit cell structure containing an elastic layer, so as to solve the limitations of the existing plate-cavity coupled resonance sound insulation structure in frequency selection and the complex problem of structural size adjustment.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is: a plate-cavity coupled resonance acoustic metamaterial unit cell structure containing an elastic layer, including a resonance plate and a cavity layer. The side part and one end part of the cavity layer are closed, the other end is open and connected to the resonance plate through an elastic layer. Narrow slits are opened on the resonance plate, and the area surrounded by the narrow slits hollowed out on the resonance plate forms a suspended part that can vibrate freely.

[0009] Preferably, the number of the cavity layers is one or more.

[0010] Preferably, when the number of the cavity layers is more than one, the multiple cavity layers are connected to each other through an elastic layer. One end of the cavity layer located at the outermost end is closed, and the other cavity layers are hollow annular structures.

[0011] Preferably, the resonance plate is made of one of aluminum alloy, iron or stainless steel; the cavity layer is made of one of PLA cavity layer, wooden cavity layer or plastic cavity layer.

[0012] Preferably, the cavity layer and the resonance plate are connected together by an adhesive or screws.

[0013] Preferably, the depth of the hollowed part of the cavity layer is 95 mm; the cross-section of the hollowed part of the cavity layer is a square ring with an outer ring side length of 200 mm and an inner ring side length of 190 mm, and the thickness of the bottom plate at one end of the cavity layer is 10 mm.

[0014] Preferably, the elastic layer is made of rubber material. Preferably, the cross-section of the elastic layer is a square ring with an outer side length of 200 mm and an inner side length of 180 mm, and the thickness of the elastic layer is 10 mm.

[0015] Preferably, the thickness of the resonance plate is 1 mm; the width of the narrow slit is 8 mm.

[0016] Preferably, the suspension part on the resonance plate is surrounded by a series of continuous narrow slits in the center of the resonance plate.

[0017] Advantages of the present invention: 1. The present invention designs a hollow thin plate with a suspended part in the center as a resonance plate. Since the solid thin plate has insufficient elasticity and a relatively high resonance frequency, in order to obtain a thin plate with better elasticity and a lower resonance frequency, a series of continuous narrow slits are made in the center of the thin plate, forming a resonance plate with a suspended part. This design enables the elastic thin plate, i.e., the resonance plate, to have the advantage of being easy to adjust the natural frequency, thus making it possible for the unit cell structure to have the first natural frequency in the infrasound frequency band. In addition, this structure has the advantages of being easy to process, lightweight, and high-strength. Particularly crucial is that the first natural frequency of the plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer described in the present invention is closely related to the first natural frequency of the resonance plate. In order to control the noise at a specific frequency, it is necessary to make the first natural frequency of the plate-cavity coupled resonance acoustic metamaterial unit cell structure match the noise frequency, which means that the first natural frequency of the resonance plate needs to be adjusted to correspond to the noise frequency. Therefore, the resonance plate plays a crucial role in the plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer. At the same time, the plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer performs well in terms of environmental protection because any materials that may be harmful to the human body or the environment are avoided in the design. In addition, the design of the plate-cavity coupled resonance unit cell structure with an elastic layer of the present invention is simple and easy to manufacture, solving the problems of complex structure and resource waste of traditional sound insulation materials; solving the limitations in frequency selection and the complex adjustment of structural dimensions of the existing plate-cavity coupled resonance sound insulation structure.

[0018] 2. The plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer described in the present invention is composed of a resonance plate, an elastic layer, and a cavity layer, allowing various materials to be used to manufacture the resonance plate, the elastic layer, and the cavity layer part. This design not only improves the adaptability of the structure, but also the selected materials are lightweight, strong, and environmentally friendly, and will not have an impact on human health. In addition, this acoustic metamaterial also has the advantages of simple structure, easy to manufacture, uncomplicated production process, and high cost-effectiveness.

[0019] 3. The present invention integrates a Helmholtz resonator and a plate-cavity coupled resonance sound insulation structure. Through simple manufacturing and assembly, the sound insulation effect of the new structure also relies on the resonance mechanism, which complements but is different from the working principle of the Helmholtz resonator, creating a new type of plate-cavity coupled resonance acoustic metamaterial unit cell structure. This design not only solves the problem of the complex internal structure of the Helmholtz resonator when dealing with low-frequency noise, but also expands the sound insulation frequency range to lower frequencies, and makes the structure size easy to adjust and the installation process simple. By simulating the sound insulation effect with COMSOL Multiphysics software, the results show that the plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer has a good sound insulation effect on noise at specific frequencies in the low-frequency range. When the first natural frequency of the resonance plate is 16.081 hz, the sound insulation amount of the plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer reaches 51.58 dB at 17 Hz. In addition, the structural design of the present invention also has the characteristics of light weight, simple structure, and high strength. The present invention is applicable to indoor and outdoor environments with high requirements for specific frequency noise control, such as computer rooms, stations, hospitals, factories and other places. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a thin-film type acoustic metamaterial; Figure 2 is a schematic structural diagram of a single Helmholtz resonator; Figure 3 is a schematic structural diagram of a plate-cavity coupled resonance sound insulation structure; Figure 4 is a three-dimensional structural diagram of a plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer; Figure 5 is a structural decomposition diagram of a plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer; Figure 6 is a schematic diagram of the cavity of a plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer; Figure 7 is a front view of the resonance plate; Figure 8 is a cross-sectional schematic diagram of the elastic layer; Figure 9 is a three-dimensional structural diagram of a single elastic layer plate-cavity coupled resonance acoustic metamaterial unit cell structure; Figure 10 is a structural decomposition diagram of a single elastic layer plate-cavity coupled resonance acoustic metamaterial unit cell structure; Figure 11 is a three-dimensional structural diagram of a plate-cavity coupled resonance acoustic metamaterial unit cell structure without an elastic layer; Figure 12It is a schematic diagram of the structural decomposition of the single-cell structure of the inelastic laminate-cavity coupled resonance acoustic metamaterial; Figure 13 It is a schematic diagram of the sound insulation simulation curve in the case where the first-order natural frequency of the resonance plate in the present invention is 16.081 hz, the cavity depth is 210 mm, the single-cell structure is a double elastic layer, and the frequency range is between 15 - 20 Hz; Figure 13 In it, the abscissa represents frequency, with the unit of hertz (Frequency / Hz), and the ordinate represents sound insulation, with the unit of decibel (Sound Transmission Loss / dB). The same applies hereinafter; Figure 14 It is a schematic diagram of the sound insulation simulation curve in the case where the first-order natural frequency of the resonance plate in the present invention is 16.081 hz, the cavity depth is 210 mm, the single-cell structure is a single elastic layer, and the frequency range is between 15 - 20 Hz; Figure 15 It is a schematic diagram of the sound insulation simulation curve in the case where the first-order natural frequency of the resonance plate in the present invention is 16.081 hz, the cavity depth is 210 mm, the single-cell structure is an inelastic layer, and the frequency range is between 15 - 20 Hz; Figure 16 It is a schematic diagram for comparing the sound insulation simulation curves of three structures: the double elastic layer structure, the single elastic layer structure, and the inelastic layer structure; Figure 17 It is a schematic diagram of the sound insulation simulation curve in the case where the first-order natural frequency of the resonance plate in the present invention is 50.743 hz, the cavity depth is 210 mm, and the frequency range is between 48 - 58 Hz; Figure 18 It is a schematic diagram of the sound insulation simulation curve in the case where the first-order natural frequency of the resonance plate in the present invention is 75.354 hz, the cavity depth is 210 mm, and the frequency range is between 76 - 86 Hz; Figure 19 It is a schematic diagram of the sound insulation simulation curve in the case where the first-order natural frequency of the resonance plate in the present invention is 100.38 hz, the cavity depth is 210 mm, and the frequency range is between 104 - 114 Hz. Detailed implementation manners

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] As Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8As shown in the figure, a single-cell structure of a plate-cavity coupled resonance acoustic metamaterial with an elastic layer includes a resonance plate 1 and a cavity layer 3. The side and one end of the cavity layer 3 are closed, the other end is open and connected to the resonance plate 1 through an elastic layer 2. A narrow slit 1.1 is provided on the resonance plate 1, and the area enclosed by the hollowing out of the narrow slit 1.1 on the resonance plate 1 forms a suspended part 1.2 that can vibrate freely.

[0023] Preferably, the number of the cavity layers 3 is one or more. When the number of the cavity layers 3 is one, the schematic diagram is Figure 9 and 10 ; when the number of the cavity layers 3 is multiple (two in this embodiment), the schematic diagram is Figure 4 、 5 and 6.

[0024] Preferably, as Figure 4 、 5 and 6, when the number of the cavity layers 3 is multiple, multiple cavity layers 3 are connected to each other through an elastic layer 2. One end of the outermost cavity layer 3 is closed, and the other cavity layers 3 are hollow annular structures.

[0025] Considering three different combinations of elastic layers to form the acoustic metamaterial single-cell structure, keeping the depth of the cavity and the first natural frequency of the resonance plate unchanged in the three combination cases. The first natural frequency of the resonance plate is 16.081 hz, and at the same time, other dimensional parameters remain unchanged. The sound insulation simulation curve of the double-elastic layer structure (such as Figure 4 、 5 and 6) reaches 51.58 dB in sound insulation at 17 hz. The sound insulation simulation curve of the single-elastic layer structure (such as Figure 9 and 10 ) reaches 38.92 dB in sound insulation at 17 hz. The sound insulation simulation curve of the non-elastic layer structure (such as Figure 11 and 12 ) reaches 32.96 dB in sound insulation at 17.9 hz. When the single-cell structure is a double-elastic layer structure, the sound insulation amount corresponding to the sound insulation peak near the resonance frequency in the sound insulation simulation curve reaches the maximum value.

[0026] Preferably, the resonance plate 1 is one of aluminum alloy, iron or stainless steel materials; the cavity layer 3 is one of PLA cavity layer, wooden cavity layer or plastic cavity layer. The resonance plate 1 is a metal plate selected with certain strength, a flat surface and non-decoration purposes.

[0027] Preferably, the cavity layer 3 and the resonance plate 1 are connected together by an adhesive or screws. One end face of the resonance plate 1 in this embodiment is bonded to the elastic layer 2 by an adhesive, and the elastic layer and the cavity layer are also directly connected by an adhesive. The adhesive can be a common adhesive or an environment-friendly adhesive, such as epoxy resin adhesive, acrylic structural adhesive, instant dry adhesive, UV adhesive, metal bonding acrylate adhesive, etc.

[0028] Preferably, the depth of the hollowed-out part of the cavity layer 3 is 95 mm; the cross-section of the hollowed-out part of the cavity layer 3 is a square ring with an outer ring side length of 200 mm and an inner ring side length of 190 mm, and the bottom plate thickness of one end of the cavity layer 3 is 10 mm. The depth of the cavity, that is, the total thickness of the unit cell structure after removing the thickness of the resonance plate and the solid plate part at the bottom of the bottom cavity layer.

[0029] Preferably, the elastic layer 2 is made of rubber material. Preferably, the cross-section of the elastic layer 2 is a square ring with an outer side length of 200 mm and an inner side length of 180 mm, and the thickness of the elastic layer 2 is 10 mm.

[0030] Preferably, the thickness of the resonance plate 1 is 1 mm; the width of the narrow slit 1.1 is 8 mm.

[0031] Preferably, the suspension part 1.2 on the resonance plate 1 is surrounded by a series of continuous narrow slits 1.1 in the center of the resonance plate 1. These narrow slits 1.1 form a thin plate structure similar to a cantilever beam in the central area of the resonance plate 1. The resonance plate 1, the elastic layer 2 and the cavity layer 3 are connected by direct adhesion, and there is no contact between the suspension part 1.2 in the center of the resonance plate 1 and the elastic layer 2 and the cavity layer 3 in contact therewith, so as to ensure that the free vibration of the suspension part 1.2 under the action of sound waves is not interfered by other structures. The continuous narrow slits 1.1 on the resonance plate 1 in this embodiment can be arranged and combined into a variety of different patterns. Therefore, the suspension part 1.2 on the resonance plate 1 can present a variety of different forms.

[0032] The working principle of the present invention is as follows: The resonance plate 1, elastic layer 2, and cavity layer 3 of the present invention are interconnected to form a plate-cavity coupled resonance acoustic metamaterial unit cell structure with an elastic layer. In the present invention, the suspension part (1.2) in the resonance plate 1 is equivalent to the elastic thin plate part in the plate-cavity coupled resonance acoustic metamaterial with an elastic layer. When combined with the elastic layer 2 and the cavity layer 3, a plate-cavity coupled resonance sound insulation structure is formed, following the sound insulation mechanism of the plate-cavity coupled resonance structure. Under the action of sound waves, after the sound waves enter the cavity, they are continuously reflected, refracted, and scattered between the cavity and the resonance plate. When the frequency of the incident sound wave matches the resonance frequency of the plate-cavity coupled resonance structure, the gaps on the resonance plate and the air in the cavity vibrate violently due to resonance, consuming sound energy, thereby reducing the energy of the sound wave penetrating to the other side and achieving the purpose of reducing noise.

[0033] Example 1 (see Figure 13 ): The plate-cavity coupled resonance acoustic metamaterial unit cell structure with a double elastic layer includes: a resonance plate 1, an elastic layer 2, and a cavity layer 3, which are compounded by an adhesive; The first natural frequency of the resonance plate used in this embodiment is 16.081 hz, the plate thickness is 1 mm, the total depth of the cavity of the unit cell structure without the resonance plate and the bottom plate thickness is 210 mm, the thickness of the elastic layer is 10 mm, the wall thickness of the hollow part of the cavity layer is 10 mm, and the thickness of the solid bottom plate of the bottom cavity layer is 10 mm. The double elastic layer structure is adhered in sequence according to the resonance plate, elastic layer, cavity layer, elastic layer, and bottom cavity layer. The resonance plate material is selected as aluminum alloy, the elastic layer material is selected as rubber, and the cavity layer is made of PLA (polylactic acid) material. The resonance plate, elastic layer, and cavity layer are fixed by direct contact. According to the sound insulation amount simulation curve obtained by COMSOL Multiphysics, it shows that the sound insulation amount of the unit cell structure reaches 51.58 dB at a frequency of 17 hz.

[0034] Example 2 (see Figure 14 ): The plate-cavity coupled resonance acoustic metamaterial unit cell structure with a single elastic layer includes: a resonance plate 1, an elastic layer 2, and a cavity layer 3, which are compounded by an adhesive; The first natural frequency of the resonance plate used in this embodiment is 16.081 hz, the plate thickness is 1 mm, the total depth of the cavity of the unit cell structure without considering the thickness of the resonance plate and the bottom plate is 210 mm, the thickness of the elastic layer is 10 mm, the wall thickness of the hollowed-out part of the cavity layer is 10 mm, and the thickness of the solid bottom plate of the bottommost cavity layer is 10 mm. The single elastic layer structure is successively adhered in the order of the resonance plate, the elastic layer, and the cavity layer. The material of the resonance plate is aluminum alloy, the material of the elastic layer is rubber, and the cavity layer is made of PLA (polylactic acid). The resonance plate, the elastic layer and the cavity layer are fixed by direct contact. According to the sound insulation simulation curve obtained by COMSOL Multiphysics, it shows that the sound insulation of the unit cell structure reaches 38.92 dB at a frequency of 17 hz.

[0035] Example 3 (see Figure 15 ): The plate-cavity coupled resonant acoustic metamaterial unit cell structure without an elastic layer includes: a resonance plate 1 and a cavity layer 3, which are compounded by an adhesive; The first natural frequency of the resonance plate used in this embodiment is 16.081 hz, the plate thickness is 1 mm, the total depth of the cavity of the unit cell structure without considering the thickness of the resonance plate and the bottom plate is 210 mm, the wall thickness of the hollowed-out part of the cavity layer is 10 mm, and the thickness of the solid bottom plate of the bottommost cavity layer is 10 mm. The non-elastic layer structure is successively adhered in the order of the resonance plate and the cavity layer. The material of the resonance plate is aluminum alloy, and the cavity layer is made of PLA (polylactic acid). The resonance plate and the cavity layer are fixed by direct contact. According to the sound insulation simulation curve obtained by COMSOL Multiphysics, it shows that the sound insulation of the unit cell structure reaches 32.96 dB at a frequency of 16.9 hz.

[0036] Example 4 (see Figure 17 ): The plate-cavity coupled resonant acoustic metamaterial unit cell structure with an elastic layer includes: a resonance plate 1, an elastic layer 2 and a cavity layer 3, which are compounded by an adhesive; The first natural frequency of the resonance plate used in this embodiment is 50.743 hz, the plate thickness is 1 mm, the total depth of the cavity of the unit cell structure without considering the thickness of the resonance plate and the bottom plate is 210 mm, the thickness of the elastic layer is 10 mm, the wall thickness of the hollowed-out part of the cavity layer is 10 mm, and the thickness of the solid bottom plate of the bottommost cavity layer is 10 mm. The material of the resonance plate is aluminum alloy, the material of the elastic layer is rubber, and the cavity layer is made of PLA (polylactic acid). The resonance plate, the elastic layer and the cavity layer are fixed by direct contact. According to the sound insulation simulation curve obtained by COMSOL Multiphysics, it shows that the sound insulation of the unit cell structure reaches 76.59 dB at a frequency of 53.3 hz.

[0037] Example 5 (see Figure 18 ): The single - cell structure of the plate - cavity coupled resonance acoustic metamaterial with an elastic layer includes: a resonance plate 1, an elastic layer 2, and a cavity layer 3, which are compounded by an adhesive. The first natural frequency of the resonance plate used in this embodiment is 75.354 hz, the plate thickness is 1 mm, the total depth of the cavity of the single - cell structure without considering the resonance plate and the bottom - plate thickness is 210 mm, the thickness of the elastic layer is 10 mm, the wall thickness of the hollowed - out part of the cavity layer is 10 mm, and the thickness of the solid bottom - plate of the bottom - most cavity layer is 10 mm. The material of the resonance plate is selected as aluminum alloy, the material of the elastic layer is selected as rubber, and the cavity layer uses PLA (polylactic acid) material. The resonance plate, the elastic layer and the cavity layer are fixed by direct contact. According to the sound insulation simulation curve obtained by COMSOL Multiphysics, it shows that the sound insulation of the single - cell structure reaches 59.67 dB at a frequency of 81.1 hz.

[0038] Example 6 (see Figure 19 ): The single - cell structure of the plate - cavity coupled resonance acoustic metamaterial with an elastic layer includes: a resonance plate 1, an elastic layer 2, and a cavity layer 3, which are compounded by an adhesive. The first natural frequency of the resonance plate used in this embodiment is 100.38 hz, the plate thickness is 1 mm, the total depth of the cavity of the single - cell structure without considering the resonance plate and the bottom - plate thickness is 210 mm, the thickness of the elastic layer is 10 mm, the wall thickness of the hollowed - out part of the cavity layer is 10 mm, and the thickness of the solid bottom - plate of the bottom - most cavity layer is 10 mm. The material of the resonance plate is selected as aluminum alloy, the material of the elastic layer is selected as rubber, and the cavity layer uses PLA (polylactic acid) material. The resonance plate, the elastic layer and the cavity layer are fixed by direct contact. According to the sound insulation simulation curve obtained by COMSOL Multiphysics, it shows that the sound insulation of the single - cell structure reaches 76.68 dB at a frequency of 109.2 hz.

[0039] The above - mentioned embodiments are only the preferred technical solutions of the present invention, and should not be regarded as limitations on the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer, comprising a resonant plate (1) and a cavity layer (3), characterized in that: The cavity layer (3) is closed at the side and one end, and is open at the other end and connected to the resonance plate (1) via the elastic layer (2). A narrow slit (1.1) is provided on the resonance plate (1), and the narrow slit (1.1) forms a suspension portion (1.2) that can vibrate freely in the hollowed-out area enclosed by the resonance plate (1).

2. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The number of the cavity layers (3) is one or more.

3. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: When there are multiple cavity layers (3), the multiple cavity layers (3) are connected to each other via the elastic layer (2), one end of the cavity layer (3) located at the outermost end is closed, and the other cavity layers (3) are hollow annular structures.

4. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The resonance plate (1) is made of one of aluminum alloy, iron or stainless steel; the cavity layer (3) is made of one of PLA cavity layer, wood cavity layer or plastic cavity layer.

5. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The cavity layer (3) and the resonance plate (1) are connected together by adhesive or screws.

6. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The depth of the hollow portion of the cavity layer (3) is 95 mm; the cross-section of the hollow portion of the cavity layer (3) is a square ring with an outer ring side length of 200 mm and an inner ring side length of 190 mm; the bottom plate at one end of the cavity layer (3) is 10 mm thick.

7. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The elastic layer (2) is made of rubber material.

8. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1 or 7, characterized in that: The cross-section of the elastic layer (2) is a square ring with an outer side length of 200 mm and an inner side length of 180 mm. The thickness of the elastic layer (2) is 10 mm.

9. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The thickness of the resonance plate (1) is 1 mm; the width of the narrow slit (1.1) is 8 mm.

10. The plate-cavity coupled resonant acoustic metamaterial unit cell structure containing an elastic layer according to claim 1, characterized in that: The suspension portion (1.2) on the resonance plate (1) is surrounded by a series of continuous narrow slits (1.1) in the center of the resonance plate (1).

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