Helmholtz resonance sound absorption-bearing integrated structure with annular embedded neck

Abstract

The invention discloses a Helmholtz resonance sound absorption-bearing integrated structure with an annular embedded neck, which comprises a plurality of cells arranged in an array, each cell comprises a honeycomb, an inner insertion pipe is embedded in the honeycomb, and a cylindrical support column is embedded in the inner insertion pipe; the low-frequency adjustable sound absorption device has excellent sub-wavelength sound absorption capacity and good bearing capacity, and in addition, the low-frequency adjustable sound absorption function can be achieved by adjusting parameters such as the radius of the neck and the radius of the neck center supporting column; the device is simple in structure and convenient to manufacture and assemble.

Description

Technical Field

[0001] The invention belongs to the technical field of air sound absorption composite structures, and in particular relates to a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck. Background Art

[0002] Achieving low-frequency sound absorption at deep subwavelength thickness has always been an important issue in the field of vibration and noise reduction. Traditional porous materials have a large number of disordered microstructures inside. Under the excitation of the incident wave, viscous energy dissipation and heat dissipation occur inside the porous material, thereby absorbing sound energy. Although porous materials have the advantages of being cheap and easy to manufacture, they have poor sound absorption effects on low-frequency sound waves. In recent years, the invention of acoustic metamaterials has provided a new solution to the problem of low-frequency sound absorption at deep subwavelength thickness. As a type of metamaterial, the inner tube structure with an embedded neck uses Helmholtz resonance to absorb low-frequency sound waves. Under the excitation of a specific sound wave, the inner tube structure will undergo Helmholtz resonance, and the air particles in the neck will vibrate violently, thereby dissipating a large amount of sound energy. However, to enhance the low-frequency sound absorption performance of the inner tube structure, it is often necessary to increase the volume of the cavity, which will cause the structure to become too bulky. In addition, the inner tube structure can only produce good sound absorption performance near the resonance frequency, which limits the broadband sound absorption performance. In practical applications, the inner tube structure often needs to face complex application scenarios, which requires a multifunctional design of sound absorption and load-bearing. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problems that the traditional Helmholtz resonance sound absorption structure has poor low-frequency sound absorption performance and lacks load-bearing capacity.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck, comprising a plurality of cells arranged in an array, each cell comprising a honeycomb, an inner tube embedded in the honeycomb, and a cylindrical pillar embedded in the inner tube.

[0005] Preferably, the inner tube is connected to the upper surface of the honeycomb.

[0006] Preferably, the inner tube is connected to the honeycomb by welding or gluing.

[0007] Preferably, the bottom end of the cylindrical support is connected to the lower surface of the honeycomb.

[0008] Preferably, the bottom end of the cylindrical support is connected to the lower surface of the honeycomb by welding or gluing.

[0009] Preferably, the height of the inner tube is smaller than the height of the honeycomb.

[0010] Preferably, the height of the cylindrical pillars is equal to the height of the honeycomb.

[0011] Preferably, the honeycomb, inner tube and cylindrical support are coaxially arranged.

[0012] Preferably, the honeycomb has a side length of 10-20 mm, a height of 20-52 mm, and a wall thickness of 0.5-3 mm.

[0013] Preferably, the inner tube has a radius of 2-5 mm, a length of 20-40 mm, and a wall thickness of 1 mm; and the cylindrical support has a radius of 1-4 mm.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck. Under the excitation of sound waves of a specific frequency, the inner tube structure undergoes Helmholtz resonance, the vibration speed of the air particles in the inner tube increases, and violent friction occurs with the wall surface, dissipating a large amount of sound energy. Since the wall surface meets the no-slip condition, the speed of the air particles on the inner tube wall surface is zero, while the speed in the central area of ​​the inner tube is the largest. Such a velocity gradient forms a ring-shaped viscous boundary layer near the inner tube wall surface. Inside the boundary layer, sound energy is converted into heat energy. Compared with the traditional inner tube structure, the presence of the cylindrical support in the center of the neck forms two annular viscous boundary layers near the inner tube wall surface and the support wall surface. The expansion of the boundary layer area means the enhancement of viscous energy dissipation, which is manifested as an improvement in sound absorption performance on a macro scale; in addition, the cylindrical support can share the pressure from the upper surface of the cell, so that it has a better load-bearing capacity.

[0015] Furthermore, the side length of the honeycomb cell is 10~20 mm, the height is 20~52 mm, and the wall thickness is 0.5~3 mm. The side length and thickness of the honeycomb cell will change the volume of the cavity inside the cell, and then change the resonance characteristics and resonance frequency of the overall structure, so that the sound absorption performance can be adjusted. By changing the wall thickness of the cell, the bearing capacity of the overall structure can be adjusted.

[0016] Furthermore, the radius of the inner tube embedded in the cavity on the upper surface of the honeycomb cell is 2-5 mm, and the length is 20-40 mm. By changing the radius and length of the inner tube, the resonance characteristics and resonance frequency of the overall structure can be changed, thereby achieving the regulation of the sound absorption performance.

[0017] Furthermore, the radius of the cylindrical pillar fixed on the lower surface of the cell is 1-4 mm, and its height is equal to the height of the cell. Adjusting the radius of the pillar can adjust the resonant frequency and peak sound absorption coefficient of the overall structure on the one hand, and the bearing capacity of the overall structure on the other hand.

[0018] In summary, the present invention can be used to manufacture lightweight and ultra-thin air sound-absorbing structures, which have excellent low-frequency sound absorption performance and good pressure-bearing capacity; in terms of design, the structural parameters and material parameters have great adjustability and can be selected according to actual working conditions, and have broad engineering application prospects.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the inner insert tube with an annular embedded neck according to the present invention; FIG2 (a) is a side view of a cell of an inner tube structure with an annular embedded neck according to the present invention; FIG2( b ) is a cell cross-sectional view of an inner tube structure with an annular embedded neck according to the present invention; FIG2( c ) is an exploded view of the cell structure of the inner tube structure with an annular embedded neck according to the present invention; FIG3 (a) is a comparison diagram of the sound absorption coefficients of the inner tube structure with an annular embedded neck in the present invention and the traditional inner tube structure in Example 1; FIG3( b ) is a comparison diagram of stress-strain curves of the inner tube structure with an annular embedded neck in Example 1 of the present invention and the traditional inner tube structure; FIG4 (a) is a comparison diagram of the sound absorption coefficients of the inner tube structure with an annular embedded neck in the present invention and the traditional inner tube structure in Example 2; FIG4( b ) is a comparison diagram of stress-strain curves of the inner tube structure with an annular embedded neck in Example 2 of the present invention and the traditional inner tube structure; Among them: 1. Honeycomb; 2. Inner tube; 3. Cylindrical support. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one side", "one end", "one side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which 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 operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0025] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0026] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0027] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0028] The present invention provides a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck, by adding a cylindrical support in the center of a traditional inner insert pipe, thereby enhancing its low-frequency sound absorption performance and mechanical load bearing performance.

[0029] See also Figure 1 The present invention discloses a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck, comprising a unit cell, wherein the unit cell is composed of a honeycomb wall, an inner insert tube and a cylindrical support, and a plurality of units are arranged in an array to form an air sound absorption structure with a thickness of 20 to 52 mm.

[0030] The side length of each cell is 10-20 mm.

[0031] Please refer to FIG. 2 , each unit cell includes: a honeycomb 1 , an embedded inner tube 2 and a cylindrical support 3 ; the honeycomb 1 and the inner tube 2 are connected by welding or gluing, and the cylindrical support 3 is fixed to the lower surface of the honeycomb 1 by welding or gluing.

[0032] The axes of the honeycomb 1 , the inner tube 2 and the cylindrical support 3 coincide with each other.

[0033] The honeycomb 1 is arranged hexagonally with an arrangement period of 10 to 20 mm. The wall thickness of the honeycomb 1 is 0.5 to 3 mm and the height is 20 to 52 mm.

[0034] The inner tube 2 has a radius of 2 to 5 mm and a length of 20 to 40 mm.

[0035] The radius of the cylindrical pillar 3 is 1-4 mm, and its height is equal to the height of the cell.

[0036] The honeycomb 1, the inner tube 2 and the support 3 are made of hard and airtight materials such as steel, which makes them have a certain bearing capacity.

[0037] The sound absorption performance of the Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck of the present invention is mainly determined by the structural dimensions of the hexagonal honeycomb, the inner insert pipe and the pillar, specifically including: the side length, height and wall thickness of the honeycomb, the radius and height of the inner insert pipe, and the radius of the pillar.

[0038] The load-bearing performance is mainly determined by the wall thickness, height and radius of the pillars of the hexagonal honeycomb.

[0039] Since these structural parameters and material parameters are adjustable, the sound absorption performance and load-bearing performance of the structure can be reasonably adjusted.

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] Example 1 Air: Density 1.23 kg / m 3 , the speed of sound is 343 m / s.

[0042] steel: Density 7850 kg / m 3 , Young's modulus 201GPa, Poisson's ratio 0.33.

[0043] Example structure size: Hexagonal honeycomb total height: H =52 mm.

[0044] Hexagonal honeycomb cell side length: a =18.58 mm.

[0045] Hexagonal honeycomb honeycomb wall thickness: t s =1 mm.

[0046] Inner tube radius: r n =4 mm.

[0047] Inner tube wall thickness: t n =1 mm.

[0048] Inner tube height: h=35mm.

[0049] Cylindrical pillar radius: r p =2 mm.

[0050] Example 2 Air: Density 1.23 kg / m 3 , the speed of sound is 343 m / s.

[0051] steel: Density 7850 kg / m3, Young's modulus 201GPa, Poisson's ratio 0.33.

[0052] Example structure size: Hexagonal honeycomb total height: H =52 mm.

[0053] Hexagonal honeycomb cell side length: a =18.58 mm.

[0054] Hexagonal honeycomb honeycomb wall thickness: t s =1 mm.

[0055] Inner tube radius: r n =6 mm.

[0056] Inner tube wall thickness: t n =1 mm.

[0057] Inner tube height: h=35mm.

[0058] Cylindrical pillar radius: r p =2.4 mm.

[0059] Examples 1 and 2 both use a pillar-free inner tube structure as a control group, the air parameters are consistent with the corresponding examples, and other parameters such as total thickness are consistent; the sound absorption coefficient of the structure at 200-350 Hz is calculated using numerical simulation.

[0060] Please refer to Figures 3(a) and (b), which are comparison diagrams of the simulated sound absorption coefficient curves and stress-strain curves of the two embodiments and the control group. The black solid line is the sound absorption coefficient curve of the Helmholtz resonance sound absorption-load-bearing integrated structure with an annular embedded neck, and the black dotted line is the sound absorption coefficient curve of the pillar-free inner tube structure.

[0061] The sound absorption coefficient of the sound absorption structure of the present invention within 200-350 Hz is greatly improved compared with the structure without pillars and the inner tube, and the mechanical bearing performance is also significantly enhanced. The average sound absorption coefficient within 200-350 Hz is increased by 76.0%, the peak sound absorption coefficient is increased by 73.4%, and the peak frequency moves to the low frequency by 13.3%; by increasing the radius ratio of the pillar and the inner tube, the peak frequency can be moved to a lower frequency, and the sound absorption coefficient can be increased to above 0.8. It has the following technical effects: 1. Excellent low-frequency sound absorption performance. The structure of the present invention can significantly improve the average sound absorption coefficient and the peak sound absorption coefficient in the low-frequency range, and the sound absorption performance is significantly improved compared to the structure without support and internal insertion tube.

[0062] 2. Good bearing capacity. The hexagonal honeycomb is made of hard materials and has good mechanical properties. The pillars inside the honeycomb can share the pressure from the upper surface of the structure, further improving the bearing capacity of the structure.

[0063] 3. With adjustable structural parameters. When the structural parameters of honeycomb, inner tube and pillar change, it will have a significant impact on the improvement of sound absorption performance and bearing capacity of the structure, and can be selected according to actual working conditions.

[0064] In summary, the present invention has a Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck, which has excellent low-frequency sound absorption performance and good pressure bearing capacity. In terms of design, the structural parameters have great adjustability and can be selected according to actual working conditions. It has a wide range of engineering application prospects and provides a new solution for the multifunctional design of air sound absorption structures.

[0065] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck, characterized in that: It comprises a plurality of cells arranged in an array, each cell comprising a honeycomb (1), an inner tube (2) being embedded in the honeycomb (1), and a cylindrical pillar (3) being embedded in the inner tube (2).

2. The Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The inner insert is connected to the upper surface of the honeycomb.

3. The Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The inner insert tube is connected to the honeycomb by welding or gluing.

4. The Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The bottom end of the cylindrical support is connected to the lower surface of the honeycomb.

5. The Helmholtz resonance sound absorption-load bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The bottom end of the cylindrical support is connected to the lower surface of the honeycomb by welding or gluing.

6. The Helmholtz resonance sound absorption and load-bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The height of the inner tube is smaller than the height of the honeycomb.

7. The Helmholtz resonance sound absorption and load-bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The height of the cylindrical pillars is equal to the height of the honeycomb.

8. The Helmholtz resonance sound absorption and load-bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The honeycomb, the inner tube and the cylindrical support are coaxially arranged.

9. The Helmholtz resonance sound absorption and load-bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The honeycomb has a side length of 10-20 mm, a height of 20-52 mm, and a wall thickness of 0.5-3 mm.

10. The Helmholtz resonance sound absorption and load bearing integrated structure with an annular embedded neck according to claim 1, characterized in that: The inner tube has a radius of 2-5 mm, a length of 20-40 mm, and a wall thickness of 1 mm; the cylindrical support has a radius of 1-4 mm.

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