Ventilation type acoustic metamaterial and reverse design method thereof

Abstract

The invention discloses a ventilation type acoustic metamaterial and a reverse design method thereof. The ventilation type acoustic metamaterial comprises a base and a plurality of acoustic units, a plurality of mounting holes are formed in the base; the acoustic unit is arranged in the mounting hole; a plurality of ventilation ducts are formed in each acoustic unit, and each ventilation duct is connected with at least one resonance silencer. According to the ventilation type acoustic metamaterial, high-efficiency sound absorption of a target frequency band can be realized while good ventilation performance is kept; and the modular structure is simple and convenient to install, and different use scenes can be quickly met.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic metamaterials, and in particular to a ventilated acoustic metamaterial and a reverse design method thereof. Background Art

[0002] The demand for environmental comfort makes noise control in ventilation systems crucial, especially in areas such as green buildings, automotive, and mechanical packaging. Noise control primarily involves two methods: sound absorption and sound insulation. Traditional sound absorption methods often utilize porous materials, fiber substrates, and microperforated panels, but these require significant thickness to effectively absorb noise at low frequencies. Traditional sound insulation methods rely on thick sound barriers, making them difficult to apply in scenarios requiring high airflow and space efficiency. None of these methods effectively address both noise control and ventilation needs. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention aims to propose a ventilated acoustic metamaterial and its inverse design method, aiming to solve the problem that existing noise control methods cannot balance noise control and ventilation.

[0004] The present invention proposes a ventilated acoustic metamaterial, which includes a base and multiple acoustic units; the base is formed with multiple mounting holes; the acoustic units are arranged in a one-to-one correspondence in the mounting holes; each acoustic unit is formed with multiple ventilation channels, the ventilation channels pass through the acoustic units, and each ventilation channel is connected to at least one resonant muffler.

[0005] The ventilated acoustic metamaterial according to the present invention can achieve efficient sound absorption in the target frequency band while maintaining good ventilation performance; the modular structure is simple and convenient to install and can quickly meet different usage scenarios.

[0006] According to some embodiments of the present invention, the resonant muffler includes a Helmholtz resonator neck and a Helmholtz resonator cavity, the Helmholtz resonator neck and the Helmholtz resonator cavity are formed in the acoustic unit, and the Helmholtz resonator neck connects the Helmholtz resonator cavity and the ventilation duct.

[0007] According to some embodiments of the present invention, a plurality of resonance silencers are cascaded on each ventilation duct, and the plurality of resonance silencers are arranged at intervals along the extension direction of the ventilation duct.

[0008] According to some embodiments of the present invention, a groove is formed at one end of the mounting hole, a limiting boss is formed at one end of the acoustic unit and is engaged with the groove, and the acoustic unit and the base are connected by the groove and the limiting boss.

[0009] According to some embodiments of the present invention, the acoustic unit is detachably connected to the base; a first clamping portion is formed in the mounting hole, and a second clamping portion is formed in the acoustic unit, and the first clamping portion and the second clamping portion are suitable for mating connection.

[0010] According to some embodiments of the present invention, a plurality of mounting holes are periodically arranged; and / or in each acoustic unit, a plurality of ventilation ducts are periodically arranged.

[0011] According to some embodiments of the present invention, the acoustic unit is made of sound-absorbing material.

[0012] According to some embodiments of the present invention, an end surface of the acoustic unit is flush with an end surface of the base.

[0013] The present invention also proposes a reverse design method for the above-mentioned ventilated acoustic metamaterial, comprising the following steps:

[0014] Construct a specific acoustic performance prediction model for an acoustic unit;

[0015] Verify the accuracy of acoustic performance prediction models;

[0016] For the target frequency band, the optimal acoustic performance of the specific acoustic unit is reversely designed based on the acoustic performance prediction model.

[0017] According to the inverse design method of the present invention, the sound absorption performance of the acoustic unit is optimized for the target frequency band based on the acoustic performance prediction model, which can improve the efficiency and accuracy of the acoustic metamaterial structure design.

[0018] According to some embodiments of the present invention, in the step of reverse designing the optimal acoustic performance of the specific acoustic unit, a machine learning method is used to reverse design the acoustic unit.

[0019] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 is a schematic structural diagram of a ventilated acoustic metamaterial according to some embodiments of the present invention;

[0022] Figure 2 is a cross-sectional view of a structure of an acoustic unit according to some embodiments of the present invention;

[0023] Figure 3is a flow chart of a reverse design method for ventilated acoustic metamaterials according to some embodiments of the present invention;

[0024] Figure 4 is a comparison chart of acoustic performance of acoustic units according to some embodiments of the present invention and a theoretical model;

[0025] Figure 5 is a flowchart of a machine learning method according to some embodiments of the present invention;

[0026] Figure 6 is a schematic diagram of a group of resonant mufflers according to some embodiments of the present invention;

[0027] Figure 7 3 is a comparison chart of acoustic performance between an acoustic unit after reverse optimization design according to some embodiments of the present invention and a theoretical model.

[0028] Reference numerals:

[0029] Base 10; mounting hole 11; groove 12;

[0030] Acoustic unit 20; ventilation duct 21; Helmholtz resonator neck 22; Helmholtz resonator cavity 23; limiting boss 24. DETAILED DESCRIPTION

[0031] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0032] Reference below Figure 1-Figure 2 A ventilated acoustic metamaterial according to an embodiment of the present invention is described.

[0033] The present invention proposes a ventilated acoustic metamaterial, which includes a base 10 and multiple acoustic units 20; the base 10 is formed with multiple mounting holes 11; the acoustic units 20 are arranged in a one-to-one correspondence within the mounting holes 11; each acoustic unit 20 is formed with multiple ventilation channels 21, the ventilation channels 21 pass through the acoustic units 20, and each ventilation channel 21 is connected to at least one resonant silencer.

[0034] In the ventilated acoustic metamaterial of this invention, each acoustic unit 20 is equipped with multiple ventilation channels 21, allowing air to circulate and achieve ventilation. Each ventilation channel 21 is connected to at least one resonant muffler. When sound waves pass through the ventilation channel 21 and the sound wave frequency matches the natural frequency of the resonant cavity, the resonant muffler dissipates the sound energy through resonance, achieving a sound reduction effect. Furthermore, the modular structure of the base 10 and acoustic units 20 facilitates simple and convenient installation, structural optimization, and maintenance. The acoustic unit 20 can be matched to the target noise requirements based on the target noise.

[0035] The ventilated acoustic metamaterial according to the present invention can achieve efficient sound absorption in the target frequency band while maintaining good ventilation performance; the modular structure is simple and convenient to install and can quickly meet different usage scenarios.

[0036] According to some embodiments of the present invention, the resonant muffler includes a Helmholtz resonator neck 22 and a Helmholtz resonator cavity 23, the Helmholtz resonator neck 22 and the Helmholtz resonator cavity 23 being formed in the acoustic unit 20, and the Helmholtz resonator neck 22 communicating with the Helmholtz resonator cavity 23 and the ventilation duct 21. Figure 2 As shown, in this embodiment, the resonant muffler is constructed as a Helmholtz resonator, and the ventilation channel 21, the Helmholtz resonator neck 22 and the Helmholtz resonator cavity 23 are all formed in the acoustic unit 20. The acoustic unit 20 can be integrally formed to simplify the processing process.

[0037] According to some embodiments of the present invention, multiple resonant silencers are cascaded on each ventilation duct 21, and the multiple resonant silencers are spaced apart along the extension direction of the ventilation duct 21. In this embodiment, multiple resonant silencers are provided on each ventilation duct 21. To address noise, the parameters of each resonant silencer can be independently designed, such as the length of the Helmholtz resonator neck 22 and the volume of the Helmholtz resonator cavity 23, to adaptively improve noise reduction performance. The provision of multiple resonant silencers in this embodiment can cover a wider frequency band, superimpose noise reduction effects, and achieve higher-precision acoustic control.

[0038] According to some embodiments of the present invention, a groove 12 is formed at one end of the mounting hole 11, and a limiting boss 24 is formed at one end of the acoustic unit 20 to cooperate with the groove 12. The acoustic unit 20 is limitedly connected to the base 10 by the groove 12 and the limiting boss 24. In this embodiment, the connection and positioning of the acoustic unit 20 and the base 10 are achieved by providing the matching groove 12 and the limiting boss 24, resulting in a simple structure and easy processing and assembly.

[0039] According to some embodiments of the present invention, the acoustic unit 20 is detachably connected to the base 10. Furthermore, a first engaging portion is formed within the mounting hole 11, and a second engaging portion is formed within the acoustic unit 20, with the first engaging portion and the second engaging portion being adapted to cooperate and connect. In this embodiment, the cooperation between the first engaging portion and the second engaging portion enables the detachable connection of the acoustic unit 20 to the base 10, maintaining the stability of the overall structure after connection. This also improves ease of assembly and disassembly, facilitating replacement and maintenance of the acoustic unit 20 as needed.

[0040] In some embodiments, as Figure 1 、 2 As shown, the cross-sections of the mounting hole 11 and the acoustic unit 20 are circular.

[0041] In some embodiments, the mounting hole 11 extends along the thickness direction of the base 10 and passes through the base 10; the acoustic unit 20 is installed in the mounting hole 11 along the thickness direction of the base 10, and its ventilation channel 21 extends along the thickness direction of the base 10 and passes through the acoustic unit 20.

[0042] According to some embodiments of the present invention, a plurality of mounting holes 11 are arranged in a periodic arrangement; and / or in each acoustic unit 20, a plurality of ventilation channels 21 are arranged in a periodic arrangement. Figure 1 As shown, multiple mounting holes 11 are arranged in an array, which can make the acoustic units 20 more evenly distributed and improve the noise reduction effect. Figure 2 As shown, multiple ventilation channels 21 are arranged in an array, which can achieve a more uniform ventilation effect and optimize the layout of the Helmholtz resonator. This embodiment can enhance the stability and predictability of the structure, help the design and optimization of acoustic metamaterials; and facilitate modular design and standardized production. In some embodiments, as Figure 1 、 2 As shown, multiple ventilation ducts 21 are evenly spaced in a circular array and arranged in multiple circles. The resonance silencers are all arranged on the radial inside or outside of the ventilation ducts 21. The layout is reasonable and can maximize the number of structures in a limited space, thereby improving ventilation and noise reduction effects.

[0043] According to some embodiments of the present invention, acoustic unit 20 is made of a sound-absorbing material. In this embodiment, using a sound-absorbing material to manufacture acoustic unit 20 can improve its sound absorption performance and further reduce noise. This embodiment overcomes structural size limitations by leveraging the synergistic effect of the resonant muffler's microstructure sound attenuation and sound absorption mechanism, enabling efficient, broadband energy control of sound waves. Specifically, the sound-absorbing material can be a porous material, for example. Acoustic unit 20 maintains a constant porosity, thereby maximizing the material's sound absorption performance.

[0044] According to some embodiments of the present invention, the end surface of the acoustic unit 20 is flush with the end surface of the base 10. In this embodiment, the end surfaces of the acoustic unit 20 are flush with the end surfaces of the base 10, respectively, making the two sides of the ventilated acoustic metamaterial a planar structure, which facilitates integration with other materials or structures (such as building walls and equipment housings), improves application adaptability, and reduces installation complexity.

[0045] The present invention also proposes a reverse design method for the above-mentioned ventilated acoustic metamaterial, such as Figure 3 As shown, the following steps are included:

[0046] S1. Constructing a specific acoustic performance prediction model of the acoustic unit 20;

[0047] S2. Verify the accuracy of the acoustic performance prediction model;

[0048] S3. For the target frequency band, based on the acoustic performance prediction model, reverse design is performed on the optimal acoustic performance of the specific acoustic unit 20.

[0049] According to the inverse design method of the present invention, based on the acoustic performance prediction model, the sound absorption performance of the acoustic unit 20 is optimized for the target frequency band, which can improve the efficiency and accuracy of the acoustic metamaterial structure design.

[0050] In some embodiments, step S1 specifically includes: using a one-dimensional scattering transfer matrix method to calculate the Figure 1 、 2 The acoustic characteristics of the acoustic unit 20 of a specific embodiment are analyzed.

[0051] A single ventilation duct 21 and a plurality of Helmholtz resonators uniformly distributed axially thereon are regarded as a resonance unit. Assuming that the sound wave is incident from the left port and emitted from the right port, the sound wave fluctuation process can be described as follows:

[0052]

[0053] Where p in and p out Respectively represent the sound pressure of the sound wave at the input end and the output end; v in and v out They represent the particle vibration velocities at the corresponding input and output ends respectively; T is the acoustic transfer matrix.

[0054] Assume that there are m types of resonance units with different structures, and the number of each type of resonance unit is The sum is N2; among them, the j-th resonance unit has Helmholtz resonators of the same structure;

[0055] Analyze the j-th resonance unit, and its acoustic transfer matrix is:

[0056]

[0057] Where, is the acoustic transfer matrix of the ventilation duct 21, is the acoustic transfer matrix of the Helmholtz resonator.

[0058] The Helmholtz resonator and a section of the ventilation channel 21 at its right end are regarded as a unit cell, and the sound pressure on both sides is

[0059] and particle velocity The transfer matrix between satisfies the following relationship:

[0060]

[0061] Where D [j] is the length of the ventilation channel 21 in a cell, and i is the imaginary unit.

[0062] The Helmholtz resonator is a classic acoustic resonator that can be equivalent to an LC circuit, where:

[0063] The acoustic impedance is:

[0064] The sound sensation is:

[0065] The voice is:

[0066] Finally, the acoustic impedance is:

[0067] Where ρ0, c0, and η represent the mass density, speed of sound, and kinematic viscosity of the air in the Helmholtz resonator, respectively; ω and k represent the angular frequency and wave number, respectively; represent the neck correction length, neck radius, and cavity volume of a single Helmholtz resonator, respectively; represents the actual neck length of a single Helmholtz resonator.

[0068] Combining the mass conservation and pressure continuity conditions before and after the acoustic unit 20, the transfer matrix is ​​obtained as follows:

[0069]

[0070] Where, is the cross-sectional area of ​​a single ventilation channel 21, S p is the cross-sectional area of ​​the entire acoustic unit 20;

[0071] Then the sound absorption coefficient α of the acoustic unit 20 is obtained as:

[0072]

[0073] In some embodiments, step S2 specifically includes: using a double-load method to perform experimental measurements on the acoustic unit 20 of the above embodiment, and comparing the experimental results with the simulation results of the theoretical model, and judging the accuracy of the acoustic performance prediction model based on the comparison results. Figure 4 As shown, it can be seen that the performance of the acoustic performance prediction model and the embodiment in the sound wave frequency range of 500Hz to 3000Hz are very consistent, verifying the accuracy of the acoustic performance prediction model in this embodiment.

[0074] According to some embodiments of the present invention, step S3 specifically includes: using a machine learning method to perform reverse design on the optimal acoustic performance of the specific acoustic unit 20.

[0075] There are many algorithms in machine learning that can perform multi-objective optimization, such as genetic algorithms and annealing algorithms. In some embodiments, the particle swarm algorithm is used. The particle swarm algorithm is a random optimization algorithm that simulates the collaborative search mechanism of individuals in a group. It searches for the optimal solution by updating the position and speed between individuals. Its flow chart is as follows: Figure 5 As shown. The main process of the particle swarm algorithm includes:

[0076] S3.1 Initialize the particle swarm and initialize the optimal position;

[0077] S3.2 calculates a penalty function and an optimal fitness value based on the current position using an acoustic performance prediction model;

[0078] S3.3 updates the optimal speed and position of particles and groups;

[0079] S3.4 checks whether the exit criteria are met; if not, repeats steps S3.2-S3.4;

[0080] S3.5 checks whether the number of cycles is satisfied; if not, repeats steps S3.1-S3.5;

[0081] S3.6 outputs the result, which is the overall best position and the best fitness value found.

[0082] During the optimization process, the ventilation ducts 21 are grouped, and the Helmholtz resonator structures on each group of ventilation ducts 21 are consistent. Since the sound absorption performance generated by each group of Helmholtz resonators is different, the grouping design can superimpose the sound absorption performance, thereby producing a wide-band sound absorption effect. Among them, the number of groups and the grouping method of the ventilation ducts 21 can be adjusted according to the target parameters. In some embodiments, the ventilation ducts 21 can be divided into 9 groups, and the grouping method is as follows: Figure 6 shown.

[0083] In some embodiments, the acoustic unit 20 is reverse-engineered for a target frequency of 1800 Hz to 2800 Hz, with a preset number of 36 ventilation ducts 21, a length of 30 mm, and a diameter of 30 mm for the acoustic unit 20. The acoustic unit 20 obtained by reverse design is compared with the acoustic performance prediction model. Figure 7 As shown by Figure 7 It can be seen that, for the target frequency, the acoustic unit 20 obtained by reverse design has a sound intensity absorption rate of more than 50% for the target frequency, has a good sound absorption effect, and can meet the target requirements.

[0084] The present invention establishes an acoustic performance prediction model for the acoustic unit 20 and combines it with a machine learning method to reverse engineer the acoustic unit 20 to optimize its noise reduction performance, thereby significantly improving design efficiency and reducing design cycle and cost.

[0085] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0086] In the description of the present invention, "first feature" and "second feature" may include one or more of the features.

[0087] In the description of the present invention, "plurality" means two or more.

[0088] In the description of the present invention, a first feature being “on” or “under” a second feature may include the first and second features being in direct contact with each other, or the first and second features not being in direct contact with each other but being in contact with each other via another feature therebetween.

[0089] In the description of the present invention, “on”, “above” and “above” a first feature of a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0090] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0091] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A ventilated acoustic metamaterial, characterized in that: include: a base, wherein the base is formed with a plurality of mounting holes; A plurality of acoustic units, wherein the acoustic units are disposed in the mounting holes in a one-to-one correspondence; Each of the acoustic units is formed with a plurality of ventilation channels, the ventilation channels passing through the acoustic unit, and each of the ventilation channels is connected to at least one resonance muffler.

2. The ventilated acoustic metamaterial according to claim 1, characterized in that The resonance muffler includes a Helmholtz resonator neck and a Helmholtz resonator cavity, wherein the Helmholtz resonator neck and the Helmholtz resonator cavity are formed in the acoustic unit, and the Helmholtz resonator neck communicates with the Helmholtz resonator cavity and the ventilation duct.

3. The ventilated acoustic metamaterial according to claim 1, wherein: A plurality of the resonance silencers are cascaded on each of the ventilation ducts, and the plurality of resonance silencers are arranged at intervals along the extension direction of the ventilation duct.

4. The ventilated acoustic metamaterial according to claim 1, wherein: A groove is formed at one end of the mounting hole, a limiting boss is formed at one end of the acoustic unit and is matched with the groove, and the acoustic unit and the base are limitedly connected via the groove and the limiting boss.

5. The ventilated acoustic metamaterial according to claim 1, wherein: The acoustic unit is detachably connected to the base; a first clamping portion is formed in the mounting hole, and a second clamping portion is formed in the acoustic unit, and the first clamping portion and the second clamping portion are suitable for cooperative connection.

6. The ventilated acoustic metamaterial according to claim 1, wherein: The plurality of mounting holes are periodically arranged; and / or in each of the acoustic units, the plurality of ventilation ducts are periodically arranged.

7. The ventilated acoustic metamaterial according to claim 1, wherein: The acoustic unit is made of sound-absorbing material.

8. The ventilated acoustic metamaterial according to claim 1, wherein: An end surface of the acoustic unit is flush with an end surface of the base.

9. A reverse design method for a ventilated acoustic metamaterial according to any one of claims 1 to 8, characterized in that: The following steps are involved: Constructing a specific acoustic performance prediction model of the acoustic unit; Verifying the accuracy of the acoustic performance prediction model; For the target frequency band, based on the acoustic performance prediction model, the optimal acoustic performance of the specific acoustic unit is reversely designed.

10. The reverse design method of ventilated acoustic metamaterial according to claim 9, characterized in that: In the step of reverse designing the optimal acoustic performance of the specific acoustic unit, a machine learning method is used to reverse design the acoustic unit.

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