Plate-type series local resonance acoustic metamaterial barrier with pressure regulation and control mechanism

Abstract

The invention belongs to the technical field of acoustic barriers, and relates to a plate-type series local resonance acoustic metamaterial barrier with a pressure regulation and control mechanism, the plate-type series local resonance acoustic metamaterial barrier is composed of sound insulation units arranged periodically, and a resonant cavity and a pressure regulation cavity which are adjacent and separated by a pressure-bearing resonance elastic plate are arranged in each sound insulation unit; the resonant cavity is defined by a surface perforated plate and a first partition plate, the surface perforated plate is opposite to the pressure-bearing resonant elastic plate, and the first partition plate is located between the surface perforated plate and the pressure-bearing resonant elastic plate; the pressure in the pressure regulating cavity is adjustable; the pressure-bearing resonance elastic plate is a semi-rigid metal plate. According to the invention, a semi-rigid metal plate is adopted as a combination of a pressure-bearing resonance elastic plate, a flexible scatterer and a fastening plate, and a pressure gas path communication cavity is designed; the problems that in the prior art, structural size changes are complex, pressure parameters and equivalent stiffness are difficult to map, and the contact interface of the scatterer and the pressure-bearing resonance elastic plate is unstable are effectively solved, and the sound insulation performance and applicability of the acoustic barrier are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of acoustic barriers and relates to a plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism. Background Art

[0002] In industrial production, low-frequency noise is a common noise pollution. Since low-frequency waves have a long wavelength (can reach several meters to tens of meters in solid structures), traditional vibration isolation materials are limited by the mass-frequency law. Only when the size of the vibration isolation material is comparable to the wavelength of the elastic wave can it have a good vibration reduction effect. Therefore, in terms of low-frequency wave vibration reduction, traditional vibration isolation materials often lead to a series of problems such as excessive structural mass and volume, high cost, etc. In response to this situation, in recent years, the blocking of low-frequency waves has been effectively achieved by constructing a local resonance mechanism. Among them, film-type and plate-type acoustic metamaterial sound insulation panels have received widespread attention due to their advantages such as low surface density and thin geometric structure.

[0003] However, at this stage, such structures still face a series of challenges in industrial applications. For thin-film acoustic metamaterial plates, constant tension control is difficult to achieve, and the weather resistance is poor. For plate-like metamaterial structures, it is difficult to achieve flexible regulation of structural parameters. At present, there are many control methods for acoustic metamaterials, including electromagnetic and mechanical methods, but these methods usually require complex peripheral equipment support, resulting in limited system applicability.

[0004] In response to this situation, a series of new control methods such as air pressure control have been proposed and gradually studied in recent years. In Reference 1 (Origami-based acoustic metamaterial for tunable and broadband sound attenuation [J]. International Journal of Mechanical Sciences, 2023, 239: 10787507889.), Reference 2 (Pneumatic soft phononic crystals with tunable band gap [J]. International Journal of Mechanical Sciences, 2023, 240: 107906-107917.), and Reference 3 (Design of tunable pneumatic metamaterials for low-frequency vibration control [J]. AIP Advances, 2024, 14: 065035-1.), the air pressure control morphoacoustic metamaterial control method mainly changes the equivalent stiffness and band gap frequency of the structure by filling the pressure cavity with compressed gas and changing the internal air pressure. However, this type of method still has the following problems:

[0005] (1) The introduction of the air pressure system significantly changes the overall properties of the structure, and the mapping relationship between the band gap characteristics of the metamaterial and its structural characteristics is usually complex, which increases the difficulty of design and regulation;

[0006] (2) In the gas pressure regulating component, the pressure parameters are difficult to directly map to the equivalent stiffness of the system, which makes it difficult to establish a parametric model of the structure.

[0007] Therefore, there is an urgent need for a plate-type series local resonant acoustic metamaterial barrier with a pressure regulation mechanism to solve the problems existing in the prior art. Summary of the invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and to provide a plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism, which is composed of periodically arranged sound insulation units, each of which is provided with a resonance cavity and a pressure regulating cavity adjacent to each other and separated by a pressure-bearing resonance elastic plate;

[0011] The resonance cavity is surrounded by a surface porous plate and a first partition plate, the surface porous plate is opposite to the pressure-bearing resonance elastic plate, and the first partition plate is located between the two;

[0012] The pressure inside the pressure regulating chamber is adjustable;

[0013] The pressure-bearing resonant elastic plate is a semi-rigid metal plate, and the ratio of the out-of-plane stiffness to the in-plane stiffness is not less than 100;

[0014] By regulating the air pressure in the pressure regulating chamber, the equivalent stiffness of the pressure-bearing resonant elastic plate can be regulated, and the local resonant frequency thereof can be regulated.

[0015] In the present invention, the surface porous plate and the resonance cavity constitute a local resonance system of the acoustic cavity, the pressure regulating cavity and the pressure-bearing resonance elastic plate constitute a local resonance system, the local resonance system of the acoustic cavity and the local resonance system are connected in series to form a coupling structure, and the coupling characteristics of multiple local resonance mechanisms are used to expand the bandwidth, thereby realizing broadband vibration isolation work.

[0016] In the prior art, since the band gap generation mechanism is related to many structural parameters, if the size of the structure changes significantly during the pressure adjustment process, it will cause complex interference in its band gap. Such complex influences are difficult to explain by establishing dynamic models and mathematical models, and can only be analyzed through experiments or finite element methods. In the present invention, since the pressure-bearing resonant elastic plate is a semi-rigid metal plate (different from flexible structures such as airbags), the ratio of the out-of-plane stiffness to the in-plane stiffness is not less than 100. Although its structural dimensions will change slightly during the change of air pressure, it can be ensured that the change occurs within a smaller range, thereby eliminating the complex interference caused by the change of structural dimensions as much as possible, and then facilitating the establishment of a direct relationship between its pressure parameters and the band gap.

[0017] In the prior art, the structural dimensions of key parts such as elastic bodies are usually changed by pressure, and the change in structural dimensions may have a relatively complex relationship with the equivalent stiffness in the local resonance mechanism, and it is not possible to directly associate the pressure parameters with the equivalent stiffness by establishing an equivalent dynamic model, so as to explain its dynamic behavior and estimate its performance. In the present invention, since the structural dimensions of the pressure-bearing resonant elastic plate only change slightly, the explanation and performance estimation can be carried out by establishing an equivalent mechanical model.

[0018] As the preferred technical solution:

[0019] In the plate-type series local resonant acoustic metamaterial barrier with a pressure regulation mechanism as described above, the Young's modulus of the pressure-bearing resonant elastic plate is 150-250GPa; or, prestress is applied to the pressure-bearing resonant elastic plate during installation to ensure that its initial stress is not less than 10MPa; in this way, the resonant elastic plate can be as flat as possible during installation, thereby eliminating installation errors caused by warping of the elastic plate during installation, so that in the process of adjusting the pressure of the pressure regulating chamber, the structural strain of the pressure-bearing resonant elastic plate is as small as possible.

[0020] As described above, a plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism is provided with a scatterer and a fastening plate inside the resonance cavity. The scatterer is fixed on the surface of the pressure-bearing resonance elastic plate facing the surface porous plate by the fastening plate. The pressure-bearing resonance elastic plate, the scatterer and the fastening plate together constitute a local resonance plate, which produces strong acoustic barrier through the local resonance effect.

[0021] In the plate-type series local resonant acoustic metamaterial barrier with a pressure regulation mechanism as described above, the fastening plate pre-presses the scatterer on the surface of the pressure-bearing resonant elastic plate facing the surface porous plate through the envelope method, thereby ensuring that after the pressure-bearing resonant elastic plate is deformed by the pressure of the pressure regulating chamber, the fixed mode of the scatterer and the pressure-bearing resonant elastic plate does not change.

[0022] In the plate-type series local resonant acoustic metamaterial barrier with a pressure regulation mechanism as described above, the scatterer is composed of a flexible material with a density of not less than 1500kg / m³, thereby ensuring that it has a high equivalent mass and flexibility, and ensuring that the pressure-bearing resonant elastic plate is deformed by changes in air pressure and fits closely with the scatterer as much as possible.

[0023] The scatterer of the present invention adopts a flexible structure, and is fastened to the pressure-bearing resonant elastic plate by means of a fastening plate through a coating method (the two can be fastened by resistance welding, etc.), so as to ensure that when the structure is in local resonance, the connection method between the flexible scatterer and the pressure-bearing resonant elastic plate does not change. In the prior art, such scatterers are fastened only by bolts or bonding with elastic elements. When resonance occurs, it is difficult to ensure the reliability of the connection interface between the elastic element and the scatterer and the constancy of the equivalent stiffness of the structure (for example, the bonding process has certain restrictions on the working environment, and it is difficult to ensure the reliability of the contact surface of the structure when resonance occurs; and due to the limitations of the contact interface of the bolt connection, there may be differences in its tensile and compressive stiffness when connected to the plate-like structure).

[0024] As described above, in the plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism, each sound insulation unit is further provided with a pressure gas path connecting cavity, the pressure gas path connecting cavity is located on the side of the pressure regulating cavity away from the resonance cavity and is connected to the pressure regulating cavity, and the pressure gas path connecting cavities of different sound insulation units are interconnected, so that the pressure regulating cavities of all the sound insulation units have the same pressure, thereby ensuring the consistency of the periodic structural performance of the plate-type local resonance acoustic metamaterial barrier.

[0025] As described above, in a plate-type series local resonant acoustic metamaterial barrier with a pressure regulation mechanism, the pressure regulating chamber is surrounded by a side plate and a second partition plate, the pressure-bearing resonant elastic plate is opposite to the side plate, the second partition plate is located between the two, and air flow holes are provided on the side plate, and the pressure gas path connecting chamber is connected with the pressure regulating chamber through the air flow holes.

[0026] As described above, in a plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism, all sound insulation units share a side plate, the pressure gas path connecting cavity is surrounded by a back plate and a third partition plate, the side plate is opposite to the back plate, and the third partition plate is located between the two.

[0027] In the plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism as described above, all sound insulation units share a surface porous plate and a pressure-bearing resonance elastic plate.

[0028] Beneficial effects:

[0029] (1) The present invention adopts a semi-rigid metal plate as a pressure-bearing resonant elastic plate. During the change of air pressure, the change of its structural dimensions is controlled within a small range, thereby eliminating the complex interference caused by the change of structural dimensions as much as possible, and facilitating the establishment of a direct relationship between pressure parameters and band gap.

[0030] (2) In the present invention, since the structural dimensions of the pressure-bearing resonant elastic plate change little, an equivalent mechanical model can be established to directly relate the pressure parameters to the equivalent stiffness, thereby explaining the dynamic behavior and estimating the performance.

[0031] (3) The present invention adopts a flexible scatterer and fastens it to the pressure-bearing resonant elastic plate in a wrapping manner through a fastening plate, thereby ensuring that the fixing mode of the scatterer and the pressure-bearing resonant elastic plate does not change when deformation occurs due to changes in air pressure, thereby improving the stability of the contact interface.

[0032] (4) The present invention provides a pressure gas path connecting cavity so that the pressure regulating cavities of all sound insulation units have the same pressure, thereby ensuring the consistency of the periodic structural performance of the plate-type local resonance acoustic metamaterial barrier and improving the overall sound insulation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is a schematic diagram of the overall structure of the plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism of the present invention (only six sound insulation units are shown in the figure);

[0034] Figure 2 It is a schematic structural diagram of a single sound insulation unit of the plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism of the present invention;

[0035] Figure 3 It is the equivalent dynamic model of the local resonance plate; Among them, 1 is a surface porous plate, 2 is a resonance cavity, 3 is a pressure regulating cavity, 4 is a pressure gas path connecting cavity, 5 is a pressure-bearing resonance elastic plate, 6 is a scatterer, 7 is a fastening plate, and 8 is an air flow hole. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0037] A plate-type series local resonance acoustic metamaterial barrier with pressure regulation mechanism, such as Figure 1 As shown, it is composed of periodically arranged sound insulation units;

[0038] like Figure 2 As shown, each sound insulation unit includes a pressure-bearing resonant elastic plate 5, a surface porous plate 1, a first baffle, a scatterer 6, a fastening plate 7, a side plate, a second baffle, a back plate and a third baffle;

[0039] The pressure-bearing resonant elastic plate 5 is a semi-rigid metal plate, and the ratio of the out-of-plane stiffness to the in-plane stiffness is not less than 100;

[0040] The Young's modulus of the pressure-bearing resonant elastic plate 5 is 150-250 GPa, and the pressure-bearing resonant elastic plate 5 is specifically a medium carbon steel plate or a spring steel plate; or, the pressure-bearing resonant elastic plate 5 is prestressed during the installation process to ensure that its initial stress is not less than 10 MPa;

[0041] The surface porous plate 1 is opposite to the pressure-bearing resonant elastic plate 5, the first partition is located between the surface porous plate 1 and the pressure-bearing resonant elastic plate 5, and the surface porous plate 1 and the first partition together form a resonant cavity 2;

[0042] The scatterer 6 is composed of a flexible material with a density of not less than 1500kg / m³, such as rubber doped with metal powder, tungsten sand, etc.; the scatterer 6 and the fastening plate 7 are arranged inside the resonance cavity 2, and the fastening plate 7 pre-presses the scatterer 6 on the surface of the pressure-bearing resonance elastic plate 5 facing the surface porous plate 1 by an enveloping method;

[0043] The side plate is opposite to the pressure-bearing resonant elastic plate 5, and an air flow hole 8 is provided on the side plate; the second partition plate is located between the side plate and the pressure-bearing resonant elastic plate 5, and the side plate and the second partition plate together enclose a pressure regulating chamber 3, and the pressure regulating chamber 3 and the resonant chamber 2 are located on both sides of the pressure-bearing resonant elastic plate 5;

[0044] The back plate is opposite to the side plate, the third partition plate is located between the back plate and the side plate, the back plate and the third partition plate together form a pressure gas path connecting chamber 4, the pressure gas path connecting chamber 4 and the pressure regulating chamber 3 are located on both sides of the side plate and are connected through the air flow hole 8;

[0045] like Figure 1 As shown, all the sound insulation units share a surface porous plate 1, a pressure-bearing resonant elastic plate 5, and a side plate.

[0046] When the acoustic metamaterial barrier is used to block low-frequency sound waves, the pressure-bearing resonant elastic plate, the scatterer and the fastening plate together constitute a local resonance plate, which produces strong acoustic blocking through the local resonance effect. The equivalent dynamic model of the local resonance plate is as follows: Figure 3 As shown;

[0047] When the incident sound wave acts on the surface porous plate, the sound wave enters the resonance cavity through the porous structure of the surface porous plate, thereby inducing the out-of-plane resonance phenomenon of the local resonance plate. When analyzing this behavior in the frequency domain, the eigenfrequency of the scatterer resonance and the eigenfrequency of the fastening plate resonance can be calculated. The calculation formula of the eigenfrequency of the scatterer resonance is as follows:

[0048] ;

[0049] In the formula, represents the eigenfrequency of the scatterer resonance (Hz), represents the out-of-plane stiffness of the resonant elastic plate under pressure (N / m), represents the equivalent stiffness of the resonant elastic plate under pressure (N / m), represents the mass of the scatterer (kg), Indicates the mass of the fastened plate (kg);

[0050] The formula for calculating the eigenfrequency of the fastened plate resonance is as follows:

[0051] ;

[0052] In the formula, represents the eigenfrequency of the fastened plate resonance (Hz), represents the total mass of the surface porous plate, the first partition, the pressure-bearing resonant elastic plate, the side plate, the second partition, the back plate and the third partition (kg);

[0053] Since the local resonance plate has two typical eigenfrequencies (i.e., scatterer resonance and fastening plate resonance), taking the scatterer resonance as an example, the equivalent stiffness K of the acoustic metamaterial barrier in the structural frequency domain can be calculated through Fourier transform. eff With equivalent mass M eff , the calculation formula is as follows:

[0054] ;

[0055] ;

[0056] Where ω represents the incident sound wave frequency (Hz). When ω is close to When the equivalent mass M eff tends to positive infinity, and the equivalent stiffness K eff It tends to negative infinity, thus blocking the transmission of sound waves.

Claims

1. A plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism, characterized in that: It is composed of periodically arranged sound insulation units, each of which is provided with a resonance cavity (2) and a pressure regulating cavity (3) adjacent to each other and separated by a pressure-bearing resonance elastic plate (5); The resonance cavity (2) is surrounded by a surface porous plate (1) and a first partition plate, the surface porous plate (1) is opposite to the pressure-bearing resonance elastic plate (5), and the first partition plate is located between the two; The pressure inside the pressure regulating chamber (3) is adjustable; The pressure-bearing resonant elastic plate (5) is a semi-rigid metal plate, and the ratio of the out-of-plane stiffness to the in-plane stiffness is not less than 100.

2. A plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism according to claim 1, characterized in that: The Young's modulus of the pressure-bearing resonant elastic plate (5) is 150-250 GPa; or, prestress is applied to the pressure-bearing resonant elastic plate (5) during installation to ensure that its initial stress is not less than 10 MPa.

3. The plate-type series local resonance acoustic metamaterial barrier with pressure regulation mechanism according to claim 1, characterized in that: A scatterer (6) and a fastening plate (7) are provided inside the resonance cavity (2); the scatterer (6) is fixed to the surface of the pressure-bearing resonance elastic plate (5) facing the surface porous plate (1) via the fastening plate (7).

4. The plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism according to claim 3, characterized in that: The fastening plate (7) pre-presses the scatterer (6) onto the surface of the pressure-bearing resonant elastic plate (5) facing the surface porous plate (1) by an enveloping method.

5. The plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism according to claim 3, characterized in that: The scatterer (6) is made of a flexible material with a density of not less than 1500 kg / m³.

6. The plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism according to claim 1, characterized in that: A pressure gas path connecting cavity (4) is also provided inside each sound insulation unit. The pressure gas path connecting cavity (4) is located on a side of the pressure regulating cavity (3) away from the resonance cavity (2) and is connected to the pressure regulating cavity (3). The pressure gas path connecting cavities (4) of different sound insulation units are connected to each other.

7. The plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism according to claim 6, characterized in that: The pressure regulating chamber (3) is surrounded by a side plate and a second partition plate. The pressure-bearing resonant elastic plate (5) is opposite to the side plate, and the second partition plate is located between the two. An air flow hole (8) is provided on the side plate, and the pressure gas path connecting chamber (4) is connected to the pressure regulating chamber (3) through the air flow hole (8).

8. The plate-type series local resonance acoustic metamaterial barrier with pressure regulation mechanism according to claim 7, characterized in that: All the sound insulation units share a side plate, and the pressure gas path connecting cavity (4) is surrounded by a back plate and a third partition plate. The side plate is opposite to the back plate, and the third partition plate is located between the two.

9. The plate-type series local resonance acoustic metamaterial barrier with a pressure regulation mechanism according to claim 1, characterized in that: All the sound insulation units share a surface porous plate (1) and a pressure-bearing resonant elastic plate (5).

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