Acoustic-vibration composite metamaterial

Abstract

The application provides a sound-vibration composite metamaterial, comprising: a metamaterial structure unit; the metamaterial structure unit comprises an elastic outer coating, a rigid inner core and an air column; the elastic outer coating is closely attached to the rigid inner core; the elastic outer coating is embedded in the rigid inner core, and a non-uniform structure with multidirectional local resonance characteristics is constructed; the metamaterial structure unit is columnar; air sound absorption performance is generated through expansion and contraction of the elastic outer coating and multimode interference between the elastic outer coating and the rigid inner core; broadband structural damping caused by dynamic vibration absorption at low frequency and multidirectional local resonance enables the metamaterial to have structural sound modulation capability. The sound-vibration composite metamaterial provided by the application can realize joint regulation of air sound and structural sound by using a basic unit with a same centimeter scale, and realizes two or more functions on a single structure; compared with directly superimposing two absorbers, the sound-vibration composite metamaterial has more excellent space utilization and lightness, and has a significant application cost advantage.

Description

Technical Field

[0001] This invention relates to the field of metamaterials, and more specifically, to acoustic-vibration composite metamaterials. Background Technology

[0002] With urbanization and industrialization, noise pollution has increasingly impacted human life, causing significant harm to health and the operational status of equipment. Among all noise problems, noise from large transportation vehicles is the most severe. The noise generated by high-speed trains, airplanes, and automobiles not only affects passenger comfort but also causes substantial environmental damage and impacts the lives of nearby residents. Therefore, the demand for effective noise reduction methods is growing rapidly. Traffic noise involves both airborne and structural noise. Airborne noise is generated by a sound source and propagates through the air. Structural noise is generated by a vibration source and radiates in all directions through the vibration of solid structures. Traditional solutions to airborne noise problems utilize porous materials, relying on their excellent sound absorption properties to dissipate sound wave energy. Classic methods for addressing structural noise problems use damping materials or dynamic vibration absorbers to absorb vibration energy and suppress structural noise propagation. However, most noise problems only focus on individual airborne and structural noise, neglecting the combined control of both. The direct superposition of airborne sound absorbers and structural sound absorbers not only affects the modulation performance of sound waves but also increases the size and weight of the equipment, reducing its space utilization. Therefore, composite metamaterials capable of simultaneously controlling airborne and structural sound have become key to solving today's noise problems and further improving the comfort, practicality, and safety of transportation equipment.

[0003] Acoustic metamaterials, as artificially designable functional materials, offer new insights into the effective manipulation of sound fields. Without altering the inherent composition of the material, multiple functions can be achieved solely through the structural design of the metamaterial platform. This structural characteristic grants metamaterials immense design freedom and macroscopically extraordinary properties not found in naturally occurring materials. Acoustic metamaterials for controlling airborne sound generally include thin-film or plate structures, Helmholtz structures, and spatially coiled structures, and are widely studied in various fields such as wavefront manipulation of airborne sound, acoustic holography, and ultrathin total sound absorption. Structural acoustic manipulation based on acoustic metamaterials primarily focuses on applying periodically arranged low-frequency resonant units to the vibrating body, generating elastic wave band gaps. For this type of metamaterial unit structure, in addition to the Bragg scattering band gap generated by geometric periodicity, local resonant band gaps can also be introduced, causing the elastic waves propagating in the main structure to transform into evanescent waves and be dissipated.

[0004] Due to the structured properties of metamaterials, the ability to modulate airborne sound and structured sound can theoretically be integrated into a single platform. Furthermore, since metamaterials capable of modulating structured sound are often composed of single-mode resonant units, their operating frequency band is limited to a narrow region. Therefore, introducing complex modes to realize composite metamaterials capable of simultaneously modulating airborne and structured sound has significant research and application value. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an acoustic-vibration composite metamaterial.

[0006] According to the present invention, a sound-vibration composite metamaterial includes: a metamaterial structural unit; the metamaterial structural unit includes an elastic outer coating, a rigid inner core, and an air column; the elastic outer coating is tightly bonded to the rigid inner core; the elastic outer coating is embedded in the rigid inner core to construct a non-uniform structure with multi-directional local resonance characteristics; the metamaterial structural unit is cylindrical; airborne sound absorption performance is generated through the expansion and contraction of the elastic outer coating and the multi-modal interference between it and the rigid inner core; the broadband structural damping caused by dynamic vibration absorption at low frequencies and multi-directional local resonance enables the metamaterial to have structural sound modulation capability.

[0007] Preferably, the material of the elastic outer coating is a closed-cell material such as EPE foam or rubber foam, or an open-cell foam with vibration performance can be obtained by further adjusting the porosity.

[0008] Preferably, the rigid inner core is made of PLA plastic or ABS plastic.

[0009] Preferably, the metamaterial structural unit can also be in the form of a tetrahedral solid.

[0010] Preferably, the rigid inner core structure is a circular open ring structure; or a square open ring structure.

[0011] Preferably, multiple metamaterial structural units are connected together, which will generate complex modes.

[0012] Preferably, the metamaterial structural unit is disposed on a vibrating substrate, and the vibrating substrate can be a regular and smooth rectangle.

[0013] Preferably, when the vibrating substrate is not a flat thin wall, the vibrating substrate is provided with a bending boundary, which divides the vibrating substrate into different regions; and the airborne sound and structural sound are jointly controlled in different regions.

[0014] Preferably, the rigid inner core is exposed and fixed to the surface of the vibrating substrate, and the elastic coating is spread out in a planar form and closely attached to the upper side of the rigid inner core.

[0015] Preferably, the sound absorption and vibration absorption characteristics of the metamaterial structural unit are characterized by finite element calculation;

[0016] The dimensional parameters of the unit structure are as follows: elastic outer coating 121 outer diameter 19.5mm, inner diameter 11.5mm, height 100mm; rigid inner core 122 outer diameter 11.5mm, inner diameter 8mm, height 100mm.

[0017] The material parameters of the unit structure are as follows: the elastic outer coating 121 has a density of 20 kg / m3, a Young's modulus of 230 (1+0.3j) kPa, and a Poisson's ratio of 0.45; the rigid inner core 122 has a density of 1180 kg / m3 and a modulus of 1910 MPa.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The acoustic-vibration composite metamaterial proposed in this invention can achieve joint control of airborne sound and structural sound with the same centimeter-scale basic unit, realizing two or more functions on a single structure; compared with directly stacking two absorbers, it has better space utilization and portability, as well as significant application cost advantages.

[0020] 2. Due to its inherent structural advantages, the acoustic-vibration composite metamaterial proposed in this invention can achieve precise control over the absorption characteristics of airborne sound and structural sound in a specified frequency band by setting the size and material parameters of the basic unit; at the same time, the structure is easy to design, has low difficulty in changing dimensions, low processing cost, and is easy to mass-produce.

[0021] 3. The present invention has a wide range of applications. Due to its excellent mechanical stability and structural strength, it can achieve good modulation capabilities of airborne sound and structural sound in various complex acoustic and vibration environments. Attached Figure Description

[0022] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0023] Figure 1 This is a schematic diagram illustrating an application scenario of the present invention;

[0024] Figure 2 This is a diagram illustrating an embodiment of the acoustic-vibration composite metamaterial whose unit structure is presented in cylindrical form.

[0025] Figure 3 This is a diagram of an embodiment of the acoustic-vibration composite metamaterial whose unit structure is presented in a tetrahedral solid form.

[0026] Figure 4This is a schematic diagram of other possible structural styles for the rigid inner core structure of the present invention;

[0027] Figure 5 This is a schematic diagram showing the possible connection methods for the unit structure of the present invention;

[0028] Figure 6 This is a schematic diagram of the arrangement of the acoustic-vibration composite metamaterial of the present invention on a vibrating substrate;

[0029] Figure 7 This is a schematic diagram of the metamaterial on the bent vibration substrate of the present invention;

[0030] Figure 8 This is a schematic diagram of metamaterials with different basic unit structures assembled according to the present invention;

[0031] Figure 9 This is a schematic diagram of the metamaterial with a rigid inner core and an outer surface, as described in this invention.

[0032] Figure 10 The diagram shows the finite element calculation results of the sound absorption coefficient of the cylindrical metamaterial provided in this embodiment of the invention.

[0033] Figure 11 The diagram shows the finite element calculation results of the vibration amplitude of the cylindrical metamaterial provided in the embodiment of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0035] Example 1:

[0036] According to the present invention, a sound-vibration composite metamaterial includes: a metamaterial structural unit; the metamaterial structural unit includes an elastic outer coating, a rigid inner core, and an air column; the elastic outer coating is tightly bonded to the rigid inner core; the elastic outer coating is embedded in the rigid inner core to construct a non-uniform structure with multi-directional local resonance characteristics; the metamaterial structural unit is cylindrical; airborne sound absorption performance is generated through the expansion and contraction of the elastic outer coating and the multi-modal interference between it and the rigid inner core; the broadband structural damping caused by dynamic vibration absorption at low frequencies and multi-directional local resonance enables the metamaterial to have structural sound modulation capability.

[0037] The elastic outer coating is made of closed-cell materials such as EPE foam or rubber foam, or by further adjusting the porosity to obtain open-cell foam with vibration performance; the rigid inner core is made of PLA plastic or ABS plastic; the metamaterial structural unit can also be a tetrahedral solid; the rigid inner core structure is a circular open-ring structure or a square open-ring structure; the lengths of the rigid inner core and the elastic outer coating can be inconsistent; multiple metamaterial structural units are connected to generate complex modes; the metamaterial structural units are set on the vibrating substrate, which can be a regular and smooth rectangle; when the vibrating substrate is not a flat thin wall, the vibrating substrate has bending boundaries, which divide the vibrating substrate into different regions; in different The region is used for joint control of airborne sound and structural sound; the rigid inner core is exposed and fixed on the surface of the vibrating substrate, and the elastic coating is spread out in a planar form and closely attached to the upper side of the rigid inner core; the metamaterial structural unit is characterized by its sound absorption and vibration absorption characteristics through finite element calculation; the dimensional parameters of the unit structure are: the outer diameter of the elastic outer coating 121 is 19.5 mm, the inner diameter is 11.5 mm, and the height is 100 mm; the outer diameter of the rigid inner core 122 is 11.5 mm, the inner diameter is 8 mm, and the height is 100 mm; the material parameters of the unit structure are: the density of the elastic outer coating 121 is 20 kg / m3, the Young's modulus is 230(1+0.3j) kPa, and the Poisson's ratio is 0.45; the density of the rigid inner core 122 is 1180 kg / m3, and the Young's modulus is 1910 MPa.

[0038] Example 2:

[0039] This invention relates to the field of metamaterials technology, specifically to an acoustic-vibration composite metamaterial and its application, and more specifically to an acoustic-vibration composite metamaterial capable of simultaneously modulating airborne sound and structural sound and its application.

[0040] To address the shortcomings of existing technologies, the present invention aims to integrate airborne sound control and structural sound control capabilities, providing a sound-vibration composite metamaterial capable of simultaneously controlling airborne sound and structural sound, and its applications.

[0041] This invention provides an acoustic-vibration composite metamaterial and its application. The acoustic metamaterial can jointly control airborne sound and structural sound, and is suitable for complex sound field environments that simultaneously contain sound sources and vibration sources.

[0042] Reference Figure 1 , Figure 1 This is a schematic diagram of an application scenario of the present invention.

[0043] like Figure 1As shown, the application scenario includes a vibrating substrate 11, an acoustic-vibration composite metamaterial 12, a sound source 13, a vibration source 14, an incident sound wave 15, an emitted sound wave 16, and a vibration excitation 17. The vibrating substrate 11 can be a plate-type device capable of vibration, such as a thin aluminum plate or a thin steel plate; the acoustic-vibration composite metamaterial 12 can be mounted on the surface of the vibrating substrate 11 to modulate the airborne sound on one side of the vibrating substrate 11 and the structural sound passing through the vibrating substrate; the sound source 13 can be an electrodynamic loudspeaker, an electromagnetic loudspeaker, etc.; and the vibration source 14 can be an electromagnetic vibration exciter, an electrodynamic vibration exciter, etc.

[0044] exist Figure 1 In the application scenario shown, the incident sound wave 15 is generated by the sound source 13, and the acoustic-vibration composite metamaterial 12 can directly modulate the airborne sound located at the direct contact surface. The vibration excitation 17 is generated by the vibration source 14, generating complex modes on the vibrating substrate 11. Through the multimodal interference of the acoustic-vibration composite metamaterial 12, the amplitude of the vibrating substrate 11 in the specified frequency band is suppressed, thereby modulating the emitted sound wave 16.

[0045] It should be noted that the sound source 13 can be located at any position in the space near the plate, and the acoustic-vibration composite metamaterial 12 can modulate sound waves incident at any angle. The vibration source 14 can be located at any point on the vibrating substrate 11, and the vibration effect is consistent on both sides of the vibrating substrate 11.

[0046] Those skilled in the art will understand that Figure 1 The system components described do not limit the application scenarios of the present invention. They may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0047] This invention provides an acoustic-vibration composite metamaterial, such as... Figure 2 The image shows an embodiment of the acoustic-vibration composite metamaterial of the present invention, in which the unit structure is presented in the form of a cylinder.

[0048] In this embodiment, the elastic outer coating 121, the rigid inner core 122, and the air column 123 constitute a metamaterial structural unit presented in a cylindrical form, wherein the elastic outer coating 121 and the rigid inner core 122 are tightly bonded together. Embedding the rigid inner core 122 within the structured elastic outer coating 121 can further construct a non-uniform structure with multi-directional local resonance characteristics. Excellent airborne sound absorption performance is generated through the expansion and contraction of the elastic outer coating 121 and its multi-modal interference with the rigid inner core 122. Notably, the dynamic vibration absorption at low frequencies and the broadband structural damping caused by multi-directional local resonance give the metamaterial excellent structural sound modulation capabilities.

[0049] In this embodiment, the material of the elastic outer coating 121 can be a closed-cell material such as EPE foam or rubber foam, or an open-cell foam with excellent vibration performance can be obtained by further adjusting the porosity. The material of the rigid inner core 122 in this embodiment can be PLA plastic, ABS plastic, etc.

[0050] It should be noted that the metamaterial elastic outer coating 121 described in this invention is not limited to the types of materials mentioned above. In practical applications, any material with elasticity and high mechanical stability can be selected. The metamaterial rigid inner core 122 described in this invention is not limited to the types of materials mentioned above. In practical applications, any rigid material with a high elastic modulus and low deformability can be selected.

[0051] This invention provides an acoustic-vibration composite metamaterial, such as... Figure 3 The image shows an embodiment of the acoustic-vibration composite metamaterial of the present invention, in which the unit structure is presented in a tetrahedral solid form.

[0052] In this embodiment, the elastic outer coating 121, the rigid inner core 122, and the air column 123 constitute a metamaterial structural unit presented in a tetrahedral form, wherein the elastic outer coating 121 and the rigid inner core 122 are tightly bonded together. Embedding the rigid inner core 122 within the structured elastic outer coating 121 further constructs a non-uniform structure with localized resonance characteristics on all four sides. Through the expansion and contraction of the elastic outer coating 121, and its multimodal interference with the rigid inner core 122, excellent airborne sound absorption performance is generated. Notably, the broadband structural damping caused by dynamic vibration absorption at low frequencies and multidirectional localized resonance gives the metamaterial excellent structural sound modulation capabilities.

[0053] In this embodiment, the material of the elastic outer coating 121 can be a closed-cell material such as EPE foam or rubber foam, or an open-cell foam with excellent vibration performance can be obtained by further adjusting the porosity. The material of the rigid inner core 122 in this embodiment can be PLA plastic, ABS plastic, etc.

[0054] It should be noted that the metamaterial elastic outer coating 121 of this invention is not limited to the types of materials mentioned above. In practical applications, any material with elasticity and high mechanical stability can be selected. The metamaterial rigid inner core 122 of this invention is not limited to the types of materials mentioned above. In practical applications, any rigid material with a high elastic modulus and low deformability can be selected.

[0055] It is worth noting that the metamaterial unit structure described in this invention is not limited to cylindrical or tetrahedral forms; different structural units can be designed according to actual application scenarios.

[0056] Reference Figure 4 , Figure 4 This is a schematic diagram of other possible structural styles for the rigid inner core structure of the present invention.

[0057] like Figure 4 As shown in the figure, (a) shows a rigid inner core structure with a circular open ring structure; (b) shows a rigid inner core structure with a square open ring structure.

[0058] Different structural styles of rigid cores will cause changes in the multimodal interference generated by metamaterials, thereby affecting their ability to modulate airborne and structural sound as well as the range of frequency bands modulated.

[0059] like Figure 5 The diagram shown illustrates the selectable connection methods for the unit structure of this invention.

[0060] To maximize the use of multimodal interference effects, each metamaterial unit structure is connected together. The connection will generate more complex modes, thereby improving the acoustic modulation capability.

[0061] Figure 5 Figure (a) shows a schematic diagram of the connection between two metamaterial unit structures; Figure (b) shows a schematic diagram of the connection between three metamaterial unit structures. Different connection methods produce different modulation effects. In practical applications, the connection method of the metamaterial unit structure can be designed according to the required modulation frequency band and modulation target.

[0062] It is worth noting that the connection method of the metamaterial unit structure of the present invention is not limited to... Figure 5 The connection method shown can be adapted to the specific needs of the situation.

[0063] like Figure 6 The diagram shown is a schematic representation of the arrangement of the acoustic-vibration composite metamaterial of the present invention on a vibrating substrate.

[0064] In practical applications, the vibrating substrate 11 is not necessarily a regular and smooth rectangle. Different arrangement methods can be selected to adapt to different substrate forms.

[0065] It is worth noting that the metamaterial arrangement described in this invention is not limited to... Figure 6 The layout shown can be adapted to different layouts depending on the specific circumstances.

[0066] like Figure 7 The diagram shown is a schematic of the metamaterial on the bent vibration substrate of the present invention.

[0067] In practical applications, the vibrating substrate 11 may not be a flat, thin-walled structure; the bending boundary 111 divides the vibrating substrate 11 into different regions. The metamaterial described in this invention achieves joint control of airborne sound and structural sound in different regions.

[0068] It is worth noting that the actual application scenarios are not limited to Figure 7 The composite metamaterial described in this invention can be installed in various bending conditions and different vibrating substrate areas to achieve sound field modulation of the entire area.

[0069] like Figure 8 The diagram shown is a schematic of the metamaterials of the present invention, which are assembled from different basic unit structures.

[0070] By arranging metamaterial embodiments in different regions, different modulation effects can be given to different regions, making the metamaterials of the present invention more flexibly applicable to different environments.

[0071] like Figure 9 The diagram shown is a schematic of the metamaterial with a rigid inner core and an outer surface according to the present invention.

[0072] In practical applications, the rigid inner core 122 can be exposed and fixed to the surface of the rigid substrate 11, and the elastic coating 124 unfolds in a planar form, closely adhering to the upper side of the rigid inner core. This embodiment no longer includes the sound absorption characteristics generated by the complex multimodal interference at the connection of the elastic coating, but adds the sound absorption characteristics generated by the resonance of the air cavity.

[0073] It should be noted that the rigid inner core described in this embodiment is not limited to... Figure 9 The arrangement shown can be designed according to the specific sound absorption frequency band required.

[0074] The sound absorption and vibration absorption properties of composite metamaterial configurations are characterized by finite element analysis.

[0075] The dimensional parameters of the unit structure are as follows: elastic outer coating 121 outer diameter 19.5mm, inner diameter 11.5mm, height 100mm; rigid inner core 122 outer diameter 11.5mm, inner diameter 8mm, height 100mm.

[0076] The material parameters of the unit structure are as follows: the elastic outer coating 121 has a density of 20 kg / m3, a Young's modulus of 230 (1+0.3j) kPa, and a Poisson's ratio of 0.45; the rigid inner core 122 has a density of 1180 kg / m3 and a modulus of 1910 MPa.

[0077] Sound absorption characteristics characterization: Refer to Figure 10 , Figure 10 The finite element method results for the sound absorption coefficient of the cylindrical metamaterial provided in this embodiment of the invention are shown.

[0078] The equations of motion and continuity of sound waves are as follows:

[0079]

[0080]

[0081] Where p, ρ, and υ represent pressure, density, and particle velocity, respectively.

[0082] Considering that when sound waves pass through a metamaterial volume element, the pressure, temperature, and density within the volume element all change, and these three quantities are interrelated, this state of change is governed by the thermodynamic equation of state. Even at low frequencies, the sound wave process proceeds relatively quickly. The compression and expansion processes of the volume element are much shorter than the time required for heat conduction. Therefore, during sound wave propagation, the medium has not yet had time to exchange heat with adjacent structures. Thus, the sound wave propagation process can be considered an adiabatic process, and the pressure p is only a function of the density ρ. That is:

[0083] p = p(ρ)

[0084] The minute increases in pressure and density caused by acoustic disturbances are:

[0085]

[0086] When a volume element is compressed, both pressure and density increase; when a volume element expands, both pressure and density decrease. Therefore, a coefficient can be obtained. Constant is positive, with c 2 This gives us the equation of state:

[0087] dp = c 2 dρ

[0088] Combining the equations of motion, continuity, and state of sound waves, we obtain:

[0089]

[0090] The sound absorption characteristics in the finite element simulation are solved using the above equations.

[0091] Sound pressure reflection coefficient γ p and sound pressure transmission coefficient τ p It can be calculated from the sound pressure field in finite element simulation, that is:

[0092] γ p =P r / P i ,

[0093] τ p =P t / P i ,

[0094] Where P r ,P t , and P iThese represent the reflected sound field intensity, transmitted sound field intensity, and incident sound field intensity in the simulation model, respectively. Using γ... p and τ p The sound absorption coefficient α of the sample model can be obtained:

[0095] α=1-|γ p | 2 -|τ p | 2

[0096] like Figure 10 As shown, for the connection pattern of the two metamaterial unit structures, significant sound absorption peaks can be achieved at 860Hz and 1200Hz, and there is a tendency for sound absorption peaks to reappear at high frequencies as the frequency increases.

[0097] It should be noted that the effect of the composite metamaterial proposed in this invention on airborne sound control is not limited to the sound absorption finite element calculation results shown in this embodiment, and can include various control effects such as sound insulation, total reflection, and frequency selection, which are not specifically limited here.

[0098] Vibration absorption characteristics characterization: Refer to Figure 11 , Figure 11 The results of finite element analysis of the vibration amplitude of the cylindrical metamaterial provided in this embodiment of the invention.

[0099] Finite element method (FEM) simulations were performed to calculate the distribution of the 16 cylindrical unit structures and their connection patterns. A unit point load signal was applied at a specified point on the vibrating substrate, and the amplitude at another point on the substrate was calculated to determine the effect of the composite metamaterial described in this invention on the structural acoustics.

[0100] In this finite element simulation, the vibrating substrate 11 is selected as a square thin aluminum plate with a thickness of 2mm and a side length of 500mm. For example... Figure 11 As shown, simulations were performed on a substrate covered by 16 large units and an empty substrate without metamaterial coverage. It can be seen that two distinct troughs occur at 300Hz and 520Hz, respectively. At 300Hz, the frequency response amplitude of the 2mm thick aluminum plate is suppressed by 40dB. Furthermore, it is noteworthy that in the remaining frequency range, the composite metamaterial can also attenuate the sharp vibration peaks of the empty substrate, exhibiting excellent vibration damping capabilities.

[0101] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0102] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0103] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A sound-vibration composite metamaterial, characterized in that, include: Metamaterial structural units; The metamaterial structural unit includes an elastic outer coating, a rigid inner core, and an air column; The elastic outer coating is tightly bonded to the rigid inner core; the elastic outer coating is embedded in the rigid inner core, constructing a non-uniform structure with multi-directional local resonance characteristics; the metamaterial structural unit is cylindrical; airborne sound absorption performance is generated through the expansion and contraction of the elastic outer coating and its multi-modal interference with the rigid inner core; the broadband structural damping caused by dynamic vibration absorption and multi-directional local resonance at low frequencies enables the metamaterial to have structural sound modulation capability; Multiple metamaterial structural units are connected together; The metamaterial structural unit is disposed on the vibrating substrate, which is a regular and smooth rectangle or a thin-walled structure that is not flat. When the vibrating substrate is not a flat thin wall, the vibrating substrate is provided with a bending boundary, which divides the vibrating substrate into different regions, and the airborne sound and structural sound are jointly controlled in different regions. The material of the elastic outer coating is EPE foam, closed-cell rubber foam, or open-cell foam with vibration properties; The rigid inner core is made of PLA plastic or ABS plastic; The dimensional parameters of the metamaterial structural unit are as follows: elastic outer coating (121) outer diameter 19.5 mm, inner diameter 11.5 mm, height 100 mm; rigid inner core (122) outer diameter 11.5 mm, inner diameter 8 mm, height 100 mm; The material parameters of the metamaterial structural unit are as follows: the elastic outer coating (121) has a density of 20 kg / m³. 3 The Young's modulus is 230 (1+0.3j) kPa, and the Poisson's ratio is 0.45; the density of the rigid inner core (122) is 1180 kg / m³. 3 .

2. The acoustic-vibration composite metamaterial according to claim 1, characterized in that, The cylindrical metamaterial structural unit is a tetrahedral solid.

3. The acoustic-vibration composite metamaterial according to claim 1, characterized in that, The rigid inner core structure is either a circular open-ring structure or a square open-ring structure.

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