Bionic sound absorption superstructure and preparation method thereof

Abstract

The invention discloses a bionic sound absorption superstructure and a preparation method, the bionic sound absorption superstructure comprises a back plate, a micro-perforated plate and a bionic bearing wall; the micro-perforated plate and the back plate are oppositely arranged; micropores are formed in the micro-perforated plate; the bionic force bearing wall is spirally arranged between the two adjacent layers of back plates and the micro-perforated plate to form a sound channel; the inlet of the sound channel is communicated with the micropore; the sound channel is in a bent shape; the side, connected with the micro-perforated plate, of the bionic force bearing wall is a first connecting end. The side, connected with the back plate, of the bionic force bearing wall is a second connecting end. The first connecting end and the second connecting end are both in a wave shape. According to the bionic sound absorption superstructure, the asymmetric wave-shaped wall structure of the cuttlebone is applied to the force bearing wall of the bionic sound absorption superstructure, by designing the shape of the bionic sound absorption superstructure and optimizing the structural parameters, the bionic sound absorption superstructure has the characteristics of light weight and high strength while keeping the low-frequency sound absorption performance, and the defects of a traditional acoustic superstructure are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic metamaterials, and in particular to the field of a bionic sound-absorbing superstructure and a preparation method thereof. Background Art

[0002] Key components of high-end equipment such as large civil aircraft cabins and deep-water submersible shells are in urgent need of lightweight, high-strength and low-frequency sound-absorbing functional structures. These components often require a combination of different single-function structures to achieve multifunctional integration. In comparison, multifunctional structures usually integrate two or more functions, greatly reducing the mass and volume of multi-material systems and helping to reduce energy consumption. However, there is a scientific contradiction between the high rigidity required for lightweight and high-strength structures and the cavity structure required for sound-absorbing structures.

[0003] Low-frequency sound dissipation is inherently weaker than high-frequency sound dissipation. Therefore, suppressing the propagation of low-frequency sound waves has always faced severe challenges in the field of engineering technology. Although traditional porous acoustic materials can improve low-frequency sound absorption by increasing thickness, this will significantly increase the weight and cost of the material, hindering the large-scale application of porous acoustic materials. The curled spatial acoustic metamaterial can reduce the thickness of the background cavity behind the micro-perforated plate to 1 / 200 of the wavelength and achieve quasi-perfect sound absorption at a specific frequency.

[0004] Cuttlefish is a marine mollusk with a bone porosity greater than 90%, and an open and bicontinuous internal porous structure. The internal structure of cuttlefish bone is stacked in layers with partitions separated by asymmetric wavy chamber walls that are continuously and evenly distributed in each layer, forming channels for internal liquid flow. The light and high-strength properties of cuttlefish bone mainly depend on the asymmetric wavy wall structure between cells, in which the amplitude of the ventral wave is significantly greater than that of the dorsal surface.

[0005] At present, structures that are both lightweight, high-strength and low-frequency sound-absorbing need further exploration. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention aims to provide a bionic sound-absorbing superstructure and a preparation method thereof. By applying the asymmetric wavy wall structure of cuttlefish bones to the load-bearing wall of the bionic sound-absorbing superstructure, the shape of the bionic sound-absorbing superstructure is designed and the structural parameters are optimized, so that the bionic sound-absorbing superstructure can maintain low-frequency sound absorption performance while also having the characteristics of light weight and high strength, thereby solving the defects of traditional acoustic superstructures.

[0007] The present invention is achieved through the following technical solutions:

[0008] A bionic sound-absorbing superstructure, comprising:

[0009] Back panel;

[0010] A micro-perforated plate, arranged opposite to the back plate; the micro-perforated plate is provided with micro-holes;

[0011] The bionic load-bearing wall is spirally arranged between two adjacent layers of the imitation back plate and the micro-perforated plate to form a sound channel; the entrance of the sound channel is connected to the micro-holes; the shape of the sound channel is bent;

[0012] Among them, the side of the bionic load-bearing wall connected to the micro-perforated plate is the first connection end; the side of the bionic load-bearing wall connected to the back plate is the second connection end; the shapes of the first connection end and the second connection end are both wavy.

[0013] In the bionic sound-absorbing superstructure, the extension curve of the first connection end is a linear sinusoidal curve, satisfying the following relationship:

[0014]

[0015] Wherein, A1 is the longitudinal amplitude of the first connection end extending along the wavy path, and p1 is the transverse period of the first connection end extending along the wavy path;

[0016] The extension curve of the second connection end is a linear sinusoidal curve, satisfying the following relationship:

[0017]

[0018] Wherein, A2 is the longitudinal amplitude of the second connection end extending along the wavy path, and p2 is the transverse period of the second connection end extending along the wavy path.

[0019] The bionic sound-absorbing structure, wherein A1 is greater than A2; and p1 is equal to p2.

[0020] The bionic sound-absorbing superstructure, wherein the width of the sound channel satisfies the following relationship:

[0021]

[0022] Wherein, w is the width of the sound channel; p is the period of the wave-shaped extension path of the bionic load-bearing wall, and the value of p is equal to p1 and p2; and k is the thickness of the bionic load-bearing wall.

[0023] 5. The bionic sound absorbing superstructure according to claim 4, characterized in that the shape of the bionic sound absorbing superstructure is a square; and the side length of the bionic sound absorbing superstructure satisfies the following relationship:

[0024]

[0025] Wherein, l is the side length of the bionic sound-absorbing superstructure; n is the number of bends of the sound channel; The folding degree of the acoustic channel is not more than The maximum integer value of .

[0026] 6 . The bionic sound absorbing superstructure according to claim 1 , wherein the side length of the bionic sound absorbing superstructure is 30 to 100 mm.

[0027] 7. The bionic sound-absorbing superstructure according to any one of claims 1 to 5, characterized in that the width of the sound channel is 10 to 15 mm;

[0028] The height of the sound channel is greater than or equal to 5 mm and less than or equal to 1 / 30 of the sound absorption peak wavelength of the bionic sound absorption superstructure.

[0029] The bionic sound-absorbing superstructure described in any one of the above items, wherein the thickness of the bionic load-bearing wall is 0.5 to 2 mm.

[0030] In any of the above-mentioned bionic sound-absorbing superstructures, the micropores are located on the central axis of the sound channel and the distance from the end of the sound channel is equal to half of the width of the sound channel; the diameter of the micropores is 1 to 8 mm.

[0031] The present application also discloses a method for preparing a bionic sound-absorbing superstructure, which is used to prepare any of the above-mentioned bionic sound-absorbing superstructures, and comprises:

[0032] Determine the fixed parameters and variable parameters of the target bionic sound absorbing superstructure;

[0033] Based on the fixed parameter and the variable parameter modeling, an air domain model is obtained;

[0034] Constructing a background sound field part, using air as a model material, using pressure acoustics and thermoviscous acoustics modules to perform calculations, optimizing the variable parameters, and obtaining an optimized model;

[0035] Based on the optimization model, the bionic sound-absorbing superstructure is printed in an integrated manner using 3D printing technology.

[0036] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0037] The present application provides a bionic sound-absorbing superstructure and a preparation method thereof. By applying the asymmetric wavy wall structure of cuttlefish bones to the load-bearing wall of the bionic sound-absorbing superstructure, the shape of the bionic sound-absorbing superstructure is designed and the structural parameters are optimized, so that the bionic sound-absorbing superstructure has the characteristics of light weight and high strength while maintaining low-frequency sound absorption performance, thereby solving the defects of traditional acoustic superstructures. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1a This is a schematic diagram of the three-dimensional structure of the cuttlefish bone reconstructed based on micro-CT scanning results;

[0040] Figure 1b It is a schematic diagram of the amplitude changes of the ventral and dorsal sections in a single layer cell of cuttlefish bone;

[0041] Figure 1c It is a schematic diagram of the maze structure between the layers of cuttlefish bone;

[0042] Figure 2 is a schematic diagram of the overall structure of the bionic sound absorbing superstructure of the present invention;

[0043] Figure 3a is a front view of the bionic sound absorbing superstructure of the present invention;

[0044] Figure 3b is a top view of the bionic sound absorbing superstructure of the present invention;

[0045] Figure 3c is a cross-sectional view of the bionic sound absorbing superstructure of the present invention;

[0046] Figure 4 Schematic diagram comparing the force-displacement curves of the bionic sound-absorbing superstructure of the present invention and the linear curled space;

[0047] Figure 5 It is a schematic diagram of the sound absorption coefficient curve of the bionic sound absorption superstructure of the present invention.

[0048] Figure 6 It is a schematic flow chart of the preparation method of the bionic sound-absorbing superstructure of the present invention.

[0049] Among them, 10, micro-perforated plate; 11, micropores; 20, bionic load-bearing wall; 21, sound channel; 30, back panel. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 only 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.

[0051] The present application is further described in detail below in conjunction with the accompanying drawings.

[0052] Based on the above problems of the prior art, Figure 1a , 1b As shown in 1c, the internal structure of the cuttlefish bone is composed of layered partitions separated by asymmetric wavy chamber walls that are continuously and evenly distributed in each layer. The chamber walls between layers are not arranged in parallel, and appear as a maze-like structure on a macro scale. The asymmetric wavy wall structure of the cuttlefish bone is applied to the present application.

[0053] like Figure 2 and Figure 3a As shown, the present invention provides a bionic sound-absorbing superstructure, which includes a back plate 30, a micro-perforated plate 10 and a bionic load-bearing wall 20; the micro-perforated plate 10 is arranged opposite to the back plate 30; the micro-perforated plate 10 is provided with micro-holes 11; the bionic load-bearing wall 20 is spirally arranged between two adjacent layers of the back plate 30 and the micro-perforated plate 10 to form a sound channel 21; the entrance of the sound channel 21 is connected to the micro-holes 11; the shape of the sound channel 21 is bent; wherein, the side of the bionic load-bearing wall 20 connected to the micro-perforated plate 10 is the first connection end; the side of the bionic load-bearing wall 20 connected to the back plate 30 is the second connection end; the shapes of the first connection end and the second connection end are both wavy.

[0054] In this embodiment, the entrance of the sound channel 21 is connected to the micropores 11. When the sound wave is incident from the micro-perforated plate 10 in the normal direction, the sound wave propagates in the curved sound channel 21. The curved sound channel 21 increases the propagation path of the sound wave, further enhancing the absorption performance of low-frequency sound waves, thereby achieving a better sound absorption effect; at the same time, the bionic load-bearing wall 20 is spirally arranged between the two adjacent back plates 30 and the micro-perforated plate 10. By applying the asymmetric wavy wall structure of the cuttlefish bone to the load-bearing wall, the compressive resistance of the bionic sound-absorbing superstructure of the present application is improved without increasing the number of bionic load-bearing walls 20 structures, and the structure has the characteristics of light weight and high strength.

[0055] Specifically, in actual use, a micro-perforated plate 10, a bionic load-bearing wall 20 and a back plate 30 are arranged from top to bottom, the micro-perforated plate 10 is provided with microholes 11, and the side of the bionic load-bearing wall 20 connected to the micro-perforated plate 10 is the first connection end; the side of the bionic load-bearing wall 20 connected to the back plate 30 is the second connection end; the shapes of the first connection end and the second connection end are both set to be wavy to further increase the compressive resistance of the sound-absorbing structure; the bionic load-bearing wall 20 is spirally arranged between two adjacent layers of the back plate 30 and the micro-perforated plate 10, which can further prevent sound wave leakage to achieve better sound absorption effect.

[0056] In another embodiment of the present invention, Figure 3b and Figure 3c As shown, the extension curve of the first connection end is a linear sinusoidal curve, satisfying the following relationship:

[0057]

[0058] Wherein, Y1 is the shape of the extension curve of the first connection end, A1 is the longitudinal amplitude of the first connection end extending along the wavy path, and p1 is the transverse period of the first connection end extending along the wavy path;

[0059] The extension curve of the second connection end is a linear sinusoidal curve, satisfying the following relationship:

[0060]

[0061] Among them, Y2 is the shape of the extension curve of the second connection end, A2 is the longitudinal amplitude of the second connection end extending along the wavy path, and p2 is the lateral period of the second connection end extending along the wavy path.

[0062] In this embodiment, the first connection end is the side where the bionic load-bearing wall 20 is connected to the micro-perforated plate 10, and the second connection end is the side where the bionic load-bearing wall 20 is connected to the back plate 30. Therefore, when the extension curves of the first connection end and the second connection end both satisfy the relationship of the linear sinusoidal function curve, the bionic load-bearing wall 20 as a whole also presents a wavy shape, and the extension path curve of the bionic load-bearing wall 20 also presents the image shape of the linear sinusoidal function curve.

[0063] Specifically, in actual use, the bionic load-bearing wall 20 is wavy in shape as a whole, so that the bionic sound-absorbing structure can remain stable when subjected to load, reduce torsion and deformation, and due to the efficient load-bearing capacity of the bionic load-bearing wall 20, the use of materials can be reduced without sacrificing the performance of the bionic sound-absorbing structure, reducing costs, so that the bionic sound-absorbing superstructure has the characteristics of small thickness and light weight. At the same time, the bionic load-bearing wall 20 is arranged in a spiral shape between the two adjacent back panels 30 and the micro-perforated plate 10, which also extends the propagation path of the sound wave, so that the bionic superstructure has the characteristics of light weight and high strength while having low-frequency sound absorption performance.

[0064] In this embodiment, A1 is greater than A2; and p1 is equal to p2, that is, the longitudinal amplitude of the first connecting end extending along the wavy path is greater than the longitudinal amplitude of the second connecting end extending along the wavy path, and the lateral period of the first connecting end extending along the wavy path is equal to the lateral period of the second connecting end extending along the wavy path.

[0065] Specifically, when A1 is greater than A2 and p1 is equal to p2, the shapes of the two ends of the bionic load-bearing wall 20 are different, and the whole presents an asymmetric wave shape. The asymmetric wave-shaped bionic load-bearing wall 20 can increase the stability of the structure without increasing the material, the overall force is more uniform, the local stress concentration is reduced, the overall stiffness of the bionic sound-absorbing superstructure is improved, and the bionic sound-absorbing superstructure has better load-bearing performance, so that the bionic sound-absorbing superstructure has the performance of light weight and high strength.

[0066] In another embodiment of the present invention, Figure 3c As shown, the width of the sound channel 21 satisfies the following relationship:

[0067]

[0068] Wherein, w is the width of the sound channel 21 ; p is the period of the wave-shaped extension path of the bionic load-bearing wall 20 , and the value of p is equal to p1 and p2 ; and k is the thickness of the bionic load-bearing wall 20 .

[0069] In this embodiment, the shape of the bionic sound absorbing superstructure is a square; the side length of the bionic sound absorbing superstructure satisfies the following relationship:

[0070]

[0071] Wherein, l is the side length of the bionic sound-absorbing superstructure; n is the number of bends of the sound channel 21; The folding degree of the acoustic channel 21 is not more than p is the period of the wavy extension path of the bionic load-bearing wall 20, and the value of p is equal to p1 and p2; k is the thickness of the bionic load-bearing wall 20.

[0072] In the formula, Calculated according to the rounding function. The rounding function satisfies the following relationship:

[0073] y = [x];

[0074] The largest integer that does not exceed the real number x is called the integer part of x, denoted as [x]. The folding degree of the acoustic channel 21 is not more than By precisely controlling the number of bends of the sound channel 21, the low-frequency sound absorption performance of the bionic sound absorption superstructure is further optimized.

[0075] Specifically, in actual use, Figure 3b and 3c As shown, the bionic sound-absorbing superstructure is square in shape as a whole, and the bionic load-bearing wall 20 is spirally distributed inside the square bionic sound-absorbing superstructure. When the structure is subjected to stress, the square bionic sound-absorbing superstructure can distribute the stress more evenly, further reducing the deformation and damage of the sound-absorbing structure caused by changes in the external environment.

[0076] In another embodiment of the present invention, the side length of the bionic sound absorbing superstructure is set to 30 to 100 mm. By controlling the side length of the bionic sound absorbing superstructure, the structure as a whole can remain lightweight while having high compressive strength.

[0077] In another embodiment of the present invention, the width of the sound channel 21 is set to be in the range of 10 to 15 mm; the height of the sound channel 21 is greater than or equal to 5 mm, and less than or equal to 1 / 30 of the peak sound absorption wavelength of the bionic sound absorption superstructure; at the same time, the cross-sectional areas of the sound channel 21 formed between two adjacent layers of the bionic bearing walls 20 are the same.

[0078] Specifically, the width of the sound channel 21 is always smaller than the side length of the bionic sound-absorbing superstructure, and the bionic load-bearing wall 20 arranged in a spiral shape between two adjacent layers of the back plate 30 and the micro-perforated plate 10 forms the sound channel 21, which can further ensure that the bionic sound-absorbing superstructure has low-frequency sound absorption performance while taking into account the characteristics of light weight and high strength.

[0079] In this embodiment, if Figure 3cAs shown, the cross-sectional areas of the sound channels 21 formed between two adjacent layers of bionic bearing walls 20 are the same. The same cross-sectional areas of the sound channels 21 can ensure that sound waves can be effectively transmitted from one sound channel to another, and the propagation characteristics of sound waves in the sound channels are consistent, so that the bionic sound-absorbing superstructure achieves better sound absorption effect as a whole. When the thickness of the bionic sound-absorbing superstructure is close to 1 / 100 of the wavelength of the sound wave, the bionic sound-absorbing superstructure can achieve a low-frequency sound absorption effect close to 100%.

[0080] In this embodiment, the folding degree of the sound channel 21 (i.e., the number of times the sound channel 21 is bent) satisfies n>3, and n is a positive integer. Therefore, multiple bends of the sound channel 21 can further extend the propagation path of the sound wave inside the structure, increase the energy dissipation of low-frequency sound waves, and achieve better sound absorption effect.

[0081] In another embodiment of the present invention, the thickness of the bionic load-bearing wall 20 is set in the range of 0.5 to 2 mm. Specifically, the thickness of the bionic load-bearing wall 20 ensures that the bionic sound-absorbing superstructure has sufficient strength and rigidity without excessively increasing weight and cost. When the thickness of the bionic load-bearing wall 20 is less than 0.5 mm, the overall thickness of the bionic load-bearing wall 20 is too thin, resulting in insufficient structural strength and rigidity, unable to bear the load, and prone to deformation or damage; when the thickness of the bionic load-bearing wall 20 is greater than 2 mm, the overall thickness of the bionic load-bearing wall 20 is too thick, resulting in an increase in its structural weight, which increases the material weight and cost.

[0082] In another embodiment of the present invention, the microhole 11 is located on the central axis of the sound channel 21 and the distance from the end of the sound channel 21 is equal to half of the width of the sound channel 21; the diameter range of the microhole 11 is set to 1 to 8 mm.

[0083] Specifically, when the sound wave is incident normally to the bionic sound-absorbing superstructure through the micropores 11 on the microperforated plate 10, the position of the micropores 11 causes the sound wave to be reflected more in the sound channel 21, increasing the contact time between the sound wave and the bionic sound-absorbing superstructure, thereby improving the sound absorption performance; at the same time, since the diameter of the micropores 11 is much smaller than the wavelength of the sound wave, the sound wave can be regarded as a plane wave, which helps to achieve better sound absorption effect by accurately adjusting the size parameters of the bionic sound-absorbing superstructure. At the same time, the diameter of the micropores 11 is always smaller than the width of the sound channel 21. The size of the diameter of the micropores 11 affects the propagation path of the sound wave in the sound channel 21, and then affects the sound absorption effect. When the diameter of the micropores 11 is smaller than the width of the sound channel 21, the bionic sound-absorbing superstructure does not need to be filled with any porous sound-absorbing material, and good broadband sound absorption can be obtained, further optimizing the overall sound absorption performance of the bionic sound-absorbing superstructure.

[0084] In this embodiment, the thickness of the micro-perforated plate 10 is set in the range of 0.2 to 5 mm, and the thickness of the back plate 30 is set in the range of 1 to 5 mm. Specifically, the back plate 30 is set as a solid thin plate. When the thickness of the back plate 30 is less than 1 mm, the back plate 30 cannot effectively suppress the leakage of sound waves. At the same time, the back plate 30 is too thin to provide sufficient support, resulting in poor stability of the bionic sound-absorbing superstructure; when the thickness of the back plate 30 is greater than 5 mm, the overall weight of the bionic sound-absorbing superstructure increases, and the material cost is also increased.

[0085] The present application also discloses a method for preparing a bionic sound-absorbing superstructure, which is used to prepare any of the above-mentioned bionic sound-absorbing superstructures, wherein the method for preparing the bionic sound-absorbing superstructure comprises:

[0086] S100, determining fixed parameters and variable parameters of a target bionic sound absorbing superstructure;

[0087] S200, obtaining an air domain model based on the fixed parameters and the variable parameters;

[0088] S300, constructing a background sound field part, using air as a model material, using pressure acoustics and thermoviscous acoustics modules for simulation, optimizing the variable parameters, and obtaining an optimized model;

[0089] S400: Based on the optimization model, the bionic sound-absorbing superstructure is integrally printed using 3D printing technology.

[0090] In this embodiment, when the sound wave is incident on the bionic sound-absorbing superstructure through the micropore 11, the sound wave can be regarded as a plane wave because the diameter of the micropore 11 is much smaller than the wavelength of the sound wave. At this time, the thermoviscous effect of the micropore 11 and the curling space cannot be ignored, so the thermoviscous acoustic theory can be used. Using the thermoviscous acoustic theory, the acoustic resistance and acoustic reactance of the micropore 11, the bionic load-bearing wall 20 and the sound channel 21 can be calculated, and then the acoustic impedance of the overall bionic superstructure unit can be obtained. By accurately setting the size parameters of the bionic sound-absorbing superstructure, the acoustic resistance can be equal to the characteristic impedance of the air, and the acoustic reactance is zero, achieving a 100% sound absorption effect at the peak frequency. In actual use, the bionic sound-absorbing superstructure should use a material with a large difference in impedance from air. When the sound wave is incident on the surface of the material, total reflection will occur, and its structural surface can be regarded as a hard boundary. Therefore, the acoustic impedance of the superstructure is only related to the shape and size parameters. Finally, a superstructure with a sound absorption effect close to 100% in a specific low-frequency range is designed.

[0091] In another embodiment of the present invention, the extension curve of the first connection end of the bionic bearing wall 20 is a linear sinusoidal curve, satisfying the following relationship:

[0092]

[0093] Wherein, A1 is the longitudinal amplitude of the first connection end extending along the wavy path, and p1 is the transverse period of the first connection end extending along the wavy path;

[0094] The extension curve of the second connection end is a linear sinusoidal curve, satisfying the following relationship:

[0095]

[0096] Wherein, A2 is the longitudinal amplitude of the second connection end extending along the wavy path, and p2 is the transverse period of the second connection end extending along the wavy path.

[0097] Furthermore, A1 is greater than A2, and p1 is equal to p2.

[0098] The width of the sound channel 21 satisfies the following relationship:

[0099]

[0100] Wherein, w is the width of the sound channel 21 ; p is the period of the wave-shaped extension path of the bionic load-bearing wall 20 , and the value of p is equal to p1 and p2 ; and k is the thickness of the bionic load-bearing wall 20 .

[0101] The shape of the bionic sound-absorbing superstructure is a square; the side length of the bionic sound-absorbing superstructure satisfies the following relationship:

[0102]

[0103] Wherein, l is the side length of the bionic sound-absorbing superstructure; n is the number of bends of the sound channel 21; The folding degree of the acoustic channel 21 is not more than The maximum integer value of .

[0104] Specifically, first, the fixed parameter values ​​of the target bionic sound-absorbing superstructure are determined: the thickness k of the bionic load-bearing wall 20 is 1 mm, the thickness b of the back plate 30 is 2 mm, the width w of the sound channel 21 is 11 mm, the tortuosity n of the sound channel 21 is 10 times, the periodic straight line side length l of the bionic sound-absorbing superstructure is 72 mm, the height h of the sound channel 21 is 25 mm, the lateral period p1 of the first connecting end extending along the wavy path and the lateral period p2 of the second connecting end extending along the wavy path are both mm, the longitudinal amplitude A1 of the first connecting end extending along the wavy path is 1.8 mm, and the longitudinal amplitude A2 of the second connecting end extending along the wavy path is 1.2 mm; the thickness t of the microperforated plate 10 and the diameter d of the micropores 11 are retained as variable parameter values ​​of the bionic sound-absorbing superstructure, wherein the thickness t of the microperforated plate 10 ranges from 0.2 to 5 mm, and the diameter d of the micropores 11 ranges from 1 to 8 mm; then, based on fixed parameter and variable parameter modeling, the air domain model is obtained.

[0105] In this embodiment, if Figure 5 As shown, the acoustic performance simulation is performed using COMSOL Multiphysics software, air is used as the model material, and the background sound field is constructed using the pressure acoustics module, wherein the incident wave is set to be a 1Pa plane wave incident along the normal direction of the micro-perforated plate 10, and the superstructure cavity part is constructed using thermoviscous acoustics. At the same time, the sound wave propagation free domain is separated by a perfect matching layer (PML) above the sound wave propagation free domain to simulate an infinite area, and the reflected wave is absorbed to avoid the influence of the secondary reflected wave on the calculation of the sound absorption coefficient of the bionic sound absorption superstructure. During the simulation process, the variable parameters are optimized, and when the thickness t of the micro-perforated plate 10 is 2 mm and the diameter d of the micropore 11 is 8 mm, the optimized model is obtained; finally, based on the optimized model, the bionic sound absorption superstructure is integratedly printed using 3D printing technology, and the sound absorption coefficient curve of the bionic sound absorption superstructure is measured by an impedance tube. When the frequency is 185.5Hz, the sound absorption coefficient of the bionic sound absorption superstructure is approximately 1, achieving a high-quality low-frequency sound absorption effect.

[0106] In this embodiment, a mechanical simulation is performed on the bionic sound-absorbing superstructure to verify the mechanical properties of the bionic sound-absorbing superstructure. First, an asymmetric wavy load-bearing wall structure of the bionic sound-absorbing superstructure and a load-bearing wall structure of a linear curled space superstructure are constructed, and the micro-perforated plate, the asymmetric wavy load-bearing wall structure of the bionic sound-absorbing superstructure and the back plate 30 are constructed as one body. At the same time, the micro-perforated plate, the load-bearing wall structure of the linear curled space superstructure and the back plate 30 are also constructed as one body; then, the bionic sound-absorbing superstructure and the linear curled space superstructure are prepared by 3D printing technology; then, a compression test is performed by a universal testing machine to obtain the force-displacement curves of the two structures respectively.

[0107] In this embodiment, if Figure 4 As shown in the figure, the maximum load that the bionic sound-absorbing superstructure can withstand before failure is about 5 times greater than that of the linear curled space superstructure. This shows that the bionic sound-absorbing superstructure has a better compressive bearing capacity than the traditional linear curled space superstructure. This shows that the bionic sound-absorbing superstructure has better compressive resistance than the traditional linear curled space superstructure and has the characteristics of light weight and high strength.

[0108] In this embodiment, the best dimensional parameters optimized in the simulation results are selected, and a bionic superstructure model can be constructed using 3D drawing software and exported as a 3D STL model. Photosensitive resin is used as the raw material and light-curing 3D printing technology is used to form the model in one piece, ultimately obtaining a lightweight, high-strength, sub-wavelength, low-frequency sound-absorbing superstructure.

[0109] In summary, the present application discloses a bionic sound-absorbing superstructure, which includes: a back plate, a micro-perforated plate and a bionic load-bearing wall; the micro-perforated plate is arranged opposite to the back plate; micro-holes are arranged on the micro-perforated plate; the bionic load-bearing wall is spirally arranged between two adjacent layers of back plates and micro-perforated plates to form a sound channel; the entrance of the sound channel is connected to the micro-holes; the shape of the sound channel is bent; wherein the side of the bionic load-bearing wall connected to the micro-perforated plate is the first connecting end; the side of the bionic load-bearing wall connected to the back plate is the second connecting end; the shapes of the first connecting end and the second connecting end are both wavy. The present application designs the shape of the bionic sound-absorbing superstructure and optimizes the structural parameters by applying the structure of the asymmetric wavy wall of cuttlefish bone to the load-bearing wall of the bionic sound-absorbing superstructure, so that the bionic sound-absorbing superstructure has the characteristics of light weight and high strength while maintaining the low-frequency sound absorption performance, thereby solving the defects of the traditional acoustic superstructure.

[0110] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0111] It should be noted that the present invention takes the bionic sound absorbing superstructure as an example to introduce the specific structure and working principle of the present invention, but the application of the present invention is not limited to the bionic sound absorbing superstructure, and can also be applied to the production and use of other similar workpieces.

[0112] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A bionic sound-absorbing superstructure, characterized in that: include: Back panel; A micro-perforated plate, arranged opposite to the back plate; the micro-perforated plate is provided with micro-holes; The bionic load-bearing wall is spirally arranged between two adjacent layers of the back plate and the micro-perforated plate to form a sound channel; the entrance of the sound channel is connected to the micro-holes; the shape of the sound channel is bent; Among them, the side of the bionic load-bearing wall connected to the micro-perforated plate is the first connection end; the side of the bionic load-bearing wall connected to the back plate is the second connection end; the shapes of the first connection end and the second connection end are both wavy.

2. The bionic sound absorbing superstructure according to claim 1, characterized in that: The extension curve of the first connection end is a linear sinusoidal curve, satisfying the following relationship: Wherein, A1 is the longitudinal amplitude of the first connection end extending along the wavy path, and p1 is the transverse period of the first connection end extending along the wavy path; The extension curve of the second connection end is a linear sinusoidal curve, satisfying the following relationship: Wherein, A2 is the longitudinal amplitude of the second connection end extending along the wavy path, and p2 is the transverse period of the second connection end extending along the wavy path.

3. The bionic sound absorbing structure according to claim 2, characterized in that: The A1 is greater than the A2; and the p1 is equal to the p2.

4. The bionic sound absorbing superstructure according to claim 3, characterized in that: The width of the sound channel satisfies the following relationship: Wherein, w is the width of the sound channel; p is the period of the wave-shaped extension path of the bionic load-bearing wall, and the value of p is equal to p1 and p2; and k is the thickness of the bionic load-bearing wall.

5. The bionic sound absorbing superstructure according to claim 4, characterized in that: The shape of the bionic sound absorbing superstructure is a square; the side length of the bionic sound absorbing superstructure satisfies the following relationship: Wherein, l is the side length of the bionic sound-absorbing superstructure; n is the number of bends of the sound channel; The folding degree of the acoustic channel is not more than Maximum integer value that can be multiplied.

6. The bionic sound absorbing superstructure according to any one of claims 1 to 5, characterized in that: The side length of the bionic sound-absorbing superstructure is 30 to 100 millimeters.

7. The bionic sound absorbing superstructure according to any one of claims 1 to 5, characterized in that: The width of the sound channel is 10 to 15 mm; The height of the sound channel is greater than or equal to 5 mm and less than or equal to 1 / 30 of the sound absorption peak wavelength of the bionic sound absorption superstructure.

8. The bionic sound absorbing superstructure according to any one of claims 1 to 5, characterized in that: The thickness of the bionic load-bearing wall is 0.5 to 2 mm.

9. The bionic sound absorbing superstructure according to any one of claims 1 to 5, characterized in that: The microhole is located on the central axis of the sound channel, and the distance between the microhole and the end of the sound channel is equal to half of the width of the sound channel; the diameter of the microhole is 1 to 8 mm.

10. A method for preparing a bionic sound-absorbing superstructure, for preparing the bionic sound-absorbing superstructure according to any one of claims 1 to 9, characterized in that: include: Determine the fixed parameters and variable parameters of the target bionic sound absorbing superstructure; Based on the fixed parameter and the variable parameter modeling, an air domain model is obtained; Constructing a background sound field part, using air as a model material, using pressure acoustics and thermoviscous acoustics modules to perform calculations, optimizing the variable parameters, and obtaining an optimized model; Based on the optimization model, the bionic sound-absorbing superstructure is printed in an integrated manner using 3D printing technology.

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