Method for sound absorption and insulation integrated honeycomb type acoustic superstructure and superstructure

Abstract

The invention discloses a sound absorption and insulation integrated honeycomb type acoustic superstructure method and a superstructure, and the method comprises the steps: carrying out the differential cutting of a honeycomb plate in the thickness direction, and forming a plurality of honeycomb matrixes which are arranged in parallel and are different in thickness; a perforated plate with non-uniform holes is laid at the front end of the honeycomb base body; for the honeycomb substrates of each thickness except the honeycomb substrate with the largest thickness, middle cover plates provided with holes for sound waves to pass through are arranged at the rear ends of the honeycomb substrates; the interiors of the honeycomb plates with different thicknesses are cut, back cavities matched with the middle cover plates are formed by combining the spaces of the multiple honeycomb units, and the back cavities are installed at the rear ends of the middle cover plates; and an integral cover plate is laid at the tail end of the back cavity, and the perforated plate, the honeycomb base body, the middle cover plate, the back cavity and the integral cover plate are tightly connected to form the sound absorption and insulation integrated honeycomb type acoustic superstructure through a bonding assisting process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of noise control technology, in particular to a sound absorption and insulation integrated honeycomb acoustic superstructure and a method thereof. BACKGROUND

[0002] Noise, as one of the main environmental pollutions, seriously affects the service life of mechanical equipment and people's daily work and normal life. Especially low-frequency noise, not only can damage mechanical equipment, but also can cause resonance of some organs of the human body, which is harmful to the human body. Long-term exposure to low-frequency noise environment can easily cause noise-induced neurasthenia, insomnia and other problems. Therefore, how to effectively control low-frequency noise has become an urgent engineering problem to be solved. The methods of noise control from the transmission path mainly include sound insulation and sound absorption. For sound absorption, the traditional sound absorption materials mainly include porous fiber materials, porous foam materials and micro-perforated plate sound absorption materials, etc., which can convert sound into heat strain energy or elastic strain energy for dissipation. However, in order to achieve good sound absorption effect, the size of the traditional materials or structures needs to reach 1 / 4 of the wavelength of the sound wave, which brings the problem of excessive thickness, making it difficult for traditional sound absorption materials to be applied to space-compact environments, which does not meet the development demand of lightweight equipment today.

[0003] The emergence of acoustic superstructure provides a new solution to overcome the shortcomings of traditional sound absorption materials, greatly expanding the concept and application field of sound absorption materials. Compared with traditional materials and structures, the representative characteristics of acoustic superstructure are strong designability, good physical performance and large sub-wavelength size. These advantages make it overcome the shortcomings of traditional sound absorption materials and structures, and have important application value in various engineering fields. There are many types of sound absorption superstructure, and the common forms include Helmholtz resonator, resonant membrane / plate structure, Fabry-Perot cavity, space-wound absorber, slit absorber and combination or derivative structure based on these basic forms. From the sound absorption principle, Helmholtz resonator can be regarded as a spring-mass vibration system, which has an absorption peak at the resonant frequency, in which the air in the neck is equivalent to the mass component, and the air in the abdomen is equivalent to the spring. Resonant membrane and resonant plate have similar principles, in which the membrane or plate acts as a spring. Generally, a mass is arranged on the membrane or plate to form a spring-mass vibration system, which also produces an absorption peak at the resonant frequency. Fabry-Perot cavity can produce an absorption peak at the frequency where the structure length is equal to 1 / 4 of the wavelength. The space-wound absorber is equivalent to a derivative structure of the Fabry-Perot cavity. The slit absorber can dissipate energy through the friction between the air in the slit and the wall, achieving sound absorption effect, which has a similar mechanism to porous materials. Although the basic structural forms of these sound absorbers have been partially proposed in traditional acoustics, these structures have become the basic units of superstructure design, and their application range has been significantly expanded.

[0004] However, the sound absorption frequency band of a single unit of the sound absorption superstructure is often narrow, and therefore, how to achieve low-frequency broadband noise reduction has become the key to the design of the sound absorption superstructure. At present, the commonly used methods for widening the sound absorption bandwidth mainly include parallel coupling design of multiple units and multi-order design of a single unit. For the parallel coupling of multiple units, multiple sound absorption superstructure units with different working frequency bands are combined, so that the combined structure can have a good noise attenuation effect in a wide frequency band. For the multi-order design of a single unit, multiple small-hole partitions are added inside the resonator cavity, the original single-degree-of-freedom system is upgraded to a multi-degree-of-freedom system, multiple nearly perfect sound absorption peaks can be obtained at higher frequencies while keeping the original peak unchanged, and the more partitions, the more peaks, and finally the peaks of the resonator can cover from low frequency to medium frequency, and even high frequency. On this basis, the working frequency band of the structure can be further widened by using the parallel coupling design of multiple units. In addition, the effective widening of the working frequency band can also be achieved by using the parallel collaborative coupling effect between different types of sound absorption superstructures.

[0005] Although the previous research can achieve sound absorption effect in a wide frequency band through a relatively thin structure, the use of thinner thickness to achieve low-frequency broadband noise reduction is still pursued at present, and in some working conditions, it may be necessary to achieve sound absorption effect and sound insulation effect at the same time. Most of the existing noise reduction superstructures only have one of the two functions, and cannot fully utilize the characteristics of the structure.

[0006] The above information disclosed in the background section is only intended to enhance the understanding of the background of the present application, and therefore can contain information that is not prior art known to those of ordinary skill in the art. SUMMARY

[0007] The present application provides a sound absorption and insulation integrated honeycomb acoustic superstructure and a method thereof, which realizes the integration of sound absorption and insulation under the premise of ensuring the lightweight of the structure.

[0008] A method for a sound absorption and insulation integrated honeycomb acoustic superstructure comprises,

[0009] The honeycomb plate is differentially cut in the thickness direction to form multiple honeycomb matrices arranged side by side and having different thicknesses;

[0010] A non-uniform perforated plate with holes is laid on the front end of the honeycomb matrix;

[0011] For each honeycomb matrix of a certain thickness except the honeycomb matrix with the largest thickness, an intermediate cover plate with sound wave passing holes is arranged at the rear end of the honeycomb matrix;

[0012] The interior of the honeycomb plate of different thicknesses is cut and processed, a back cavity is formed by combining the space of multiple honeycomb units to adapt to each intermediate cover plate, and the back cavity is installed at the rear end of the intermediate cover plate.

[0013] An overall cover plate is laid at the end of the back cavity, and an adhesion process is used to tightly connect the perforated plate, the honeycomb matrix, the intermediate cover plate, the back cavity and the overall cover plate to form an integrated honeycomb acoustic superstructure.

[0014] In the method, each honeycomb matrix of each thickness contains at least two honeycomb units, and the number of holes in the perforated plate corresponding to each honeycomb unit is in gradient distribution, and all the perforated radii corresponding to the same honeycomb unit are the same or different.

[0015] In the method, the perforated radii corresponding to different honeycomb units are the same.

[0016] In the method, the thickness of each intermediate cover plate is the same, the position of the hole in each intermediate cover plate is coaxial with the center of one of the honeycomb units in the corresponding honeycomb matrix, and the size of the hole is adjusted to adjust the noise reduction effect of the honeycomb acoustic superstructure in the low frequency band.

[0017] In the method, the rear end of each intermediate cover plate is provided with an independent back cavity, and the thickness of each back cavity is determined as follows: taking the thickness of the honeycomb matrix with the largest thickness as the reference value, subtracting the thickness of the corresponding honeycomb matrix, and then subtracting the thickness of the intermediate cover plate, the difference is the thickness of the back cavity.

[0018] In the method, the material of the honeycomb plate is selected from at least one of paper-based composite material, metal-based composite material and ceramic-based composite material, and the material of the perforated plate, the intermediate cover plate and the overall cover plate is selected from any one of metal, polymer material, composite material and inorganic non-metal.

[0019] In the method, the thickness of the honeycomb matrix is non-uniformly distributed, and at least two honeycomb matrices of different thicknesses are included to form sound absorption responses in multiple working frequency bands.

[0020] In the method, the thickness of the honeycomb acoustic superstructure is 1 / 23 of the lowest sound absorption wavelength, the number of holes corresponding to each honeycomb unit in the perforated plate is not exactly the same, and a perforation rate gradient distribution is formed to broaden the sound absorption band.

[0021] In the method, the thickness of the honeycomb acoustic superstructure is less than 50 mm, and the surface density is less than 5 kg / m².

[0022] A honeycomb acoustic superstructure is made according to the method, and the honeycomb acoustic superstructure has an average sound absorption coefficient of not less than 0.8 in a frequency range of 400-4000 Hz, a weighted sound insulation of not less than 20 dB, and a total thickness of not more than 1 / 20 of the minimum sound absorption wavelength.

[0023] Compared with the prior art, the present application has the following advantages: the present application comprehensively utilizes the parallel coupling effect between the sound absorption units and the sound absorption supercells by the gradient perforation rate design and the non-uniform thickness design, meanwhile, the structure space is fully utilized, the back cavity structure is introduced, the low-frequency resonance enhancement mechanism of the back cavity is utilized, and the noise reduction effect of the whole structure in the low-frequency band is improved, and overall, high-efficiency noise reduction in a low-frequency wideband range can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Various other advantages and benefits of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a better understanding of the preferred embodiments and are not to be considered as limitations on the present application. It should be readily understood that the drawings are merely exemplary of the present application and are, therefore, not to be considered as limiting the scope of the application. It should be readily understood that the drawings are merely exemplary of the present application and are, therefore, not to be considered as limiting the scope of the application. It should be readily understood that the drawings described below are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative labor for those of ordinary skill in the art. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0025] In the drawings:

[0026] Figure 1 is a schematic diagram of a sound absorption and insulation integrated honeycomb acoustic superstructure of the present application;

[0027] Figure 2 is a detailed component schematic diagram of the honeycomb acoustic superstructure;

[0028] Figure 3 is a related parameter schematic diagram of the holes in the perforated plate and the intermediate cover plate in the honeycomb acoustic superstructure;

[0029] Figure 4a is a sound absorption coefficient simulation calculation result schematic diagram of the honeycomb acoustic superstructure; Figure 4b is a sound insulation amount simulation calculation result schematic diagram of the honeycomb acoustic superstructure;

[0030] Figure 5a is a sample photograph of a large-size honeycomb acoustic superstructure; Figure 5b is a sound absorption coefficient experimental test result of a large-size honeycomb acoustic superstructure; Figure 5c is a sound insulation amount experimental test result of a large-size honeycomb acoustic superstructure.

[0031] The present application will be further explained in combination with the drawings and embodiments below. DETAILED DESCRIPTION

[0032] The present application will be described below with reference to the drawings. Figures 1 to 5c The specific embodiments of the present application will now be described in more detail. While the specific embodiments of the present application are shown in the drawings, it is noted that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood, and so that the scope of the present application can be fully conveyed to those skilled in the art.

[0033] It should be noted that certain terms are used throughout the present specification and claims which have particular meanings as set forth below. Those skilled in the art will understand that one equivalent term can be substituted for another, and still be within the scope of the present application. The present specification and claims are not to be limited by terminology. The description that follows is intended to provide a more thorough understanding of the subject application, and is not intended to be a description of the only modes of practicing the subject application. The description that follows is intended to provide a more thorough understanding of the subject application, and is not intended to be a description of the only modes of practicing the subject application. The scope of the subject application is defined solely by the claims that follow this description.

[0034] In order to make the present application more clearly understood, the following further explanations will be given with specific examples in conjunction with the accompanying drawings, which do not limit the present application.

[0035] As shown in the drawings, a method for manufacturing a sound absorption and insulation integrated honeycomb acoustic superstructure comprises the following steps. Figure 1

[0036] The honeycomb plates are cut in different thickness directions to form a plurality of honeycomb bases 2 arranged in parallel and having different thicknesses.

[0037] The perforated plate 1 with non-uniform holes is laid on the front end of the honeycomb base 2.

[0038] For each honeycomb base 2 except the one with the largest thickness, an intermediate cover plate 3 with sound wave passing holes is arranged at the back end thereof.

[0039] The interiors of the honeycomb plates with different thicknesses are cut to form back cavities 4 adapted to the intermediate cover plates 3 by combining the spaces of a plurality of honeycomb units, and the back cavities 4 are installed at the back ends of the intermediate cover plates 3.

[0040] An overall cover plate 5 is laid at the end of the back cavity 4, and an adhesion process is performed to tightly connect the perforated plate 1, the honeycomb base 2, the intermediate cover plate 3, the back cavity 4, and the overall cover plate 5 to form the sound absorption and insulation integrated honeycomb acoustic superstructure.

[0041] ​For the above embodiments, the application utilizes the parallel coupling effect between the sound absorption units and the sound absorption supercells by gradient perforation rate design and non-uniform thickness design, at the same time, makes full use of the structural space, introduces the back cavity structure, utilizes the low frequency resonance enhancement mechanism of the back cavity, improves the noise reduction effect of the whole structure in the low frequency band, and overall realizes efficient noise reduction in the low frequency wide band.

[0042] Further, the application can simultaneously exert excellent sound insulation performance through the synergistic sound absorption mechanism, realizes the functional integration of sound absorption and sound insulation; compared with the traditional honeycomb structure, has more tunable parameters, can design a satisfactory honeycomb acoustic superstructure according to the target frequency band noise reduction demand, has the advantage of strong structural design; the thickness of the sound absorption and insulation integrated honeycomb acoustic superstructure is 1 / 23 of the lowest sound absorption wavelength, has the advantage of light and thin, and has simple structure, good noise reduction effect, wide application prospect, can be widely applied to the roof, side wall of the rail vehicle and other working occasions requiring sound absorption and insulation, and has important application value. The honeycomb acoustic superstructure provided by the application can realize good noise attenuation effect in a low frequency wide band with a relatively thin thickness. The device utilizes the parallel coupling effect between the sound absorption units and the sound absorption supercells by gradient perforation rate design and non-uniform thickness design, at the same time, makes full use of the structural space, introduces the back cavity structure, utilizes the low frequency resonance enhancement mechanism of the back cavity, improves the noise reduction effect of the whole structure in the low frequency band, and overall realizes the noise reduction effect in the low frequency wide band. In addition, the honeycomb acoustic superstructure not only has good sound absorption effect, but also can simultaneously exert excellent sound insulation performance through the synergistic sound absorption mechanism, and overall realizes the functional integration of sound absorption and sound insulation. The thickness of the sound absorption and insulation integrated honeycomb acoustic superstructure disclosed by the application is only 1 / 23 of the lowest sound absorption wavelength, has the advantage of light and thin, and has simple structure, good noise reduction effect, wide application prospect, can be widely applied to the roof, side wall of the rail vehicle and other working occasions requiring sound absorption and insulation, and has important application value.

[0043] In a preferred embodiment of the method, each honeycomb base body 2 of each thickness comprises at least two honeycomb units, and the number of openings in the perforated plate 1 corresponding to each honeycomb unit is in a gradient distribution, and all the perforated radii corresponding to the same honeycomb unit are the same.

[0044] In a preferred embodiment of the method, the perforated radii corresponding to different honeycomb units are the same or different.

[0045] In a preferred embodiment of the method, the thickness of each intermediate cover plate 3 is the same, the position of the opening in each intermediate cover plate 3 is in a coaxial relationship with the center of one of the honeycomb units in the corresponding honeycomb base body 2, and the noise reduction effect of the honeycomb acoustic superstructure in the low frequency band is adjusted by adjusting the size of the opening.

[0046] In the preferred embodiment of the method, the back cavity 4 corresponding to each intermediate cover plate 3 is provided independently, and the thickness of each back cavity 4 is determined by taking the thickness of the honeycomb base 2 with the largest thickness as the reference value, subtracting the thickness of the honeycomb base 2 corresponding to the back cavity 4, and then subtracting the thickness of the intermediate cover plate 3, and the difference is the thickness of the back cavity 4.

[0047] In the preferred embodiment of the method, the material of the honeycomb panel is selected from at least one of paper-based composite material, metal-based composite material, and ceramic-based composite material, and the material of the perforated plate 1, the intermediate cover plate 3, and the overall cover plate 5 is selected from any one of metal, polymer material, composite material, and inorganic non-metal.

[0048] In the preferred embodiment of the method, the thickness of the honeycomb base 2 is non-uniformly distributed, and at least two different thicknesses of the honeycomb base 2 are included to form sound absorption responses in multiple frequency bands.

[0049] In the preferred embodiment of the method, the thickness of the honeycomb acoustic superstructure is 1 / 23 of the lowest sound absorption wavelength, and the number of openings corresponding to each honeycomb cell in the perforated plate 1 is not completely the same, forming a gradient distribution of perforation rate to broaden the sound absorption frequency band. For each honeycomb base with a certain thickness, the number of openings corresponding to each honeycomb cell in the perforated plate is different. For the entire perforated plate, because the entire structure is equivalent to a plurality of honeycomb bases in parallel, the number and regularity of openings on the perforated plate corresponding to each honeycomb base are consistent, so the number of openings corresponding to each honeycomb cell in the perforated plate is the same.

[0050] In the preferred embodiment of the method, the thickness of the honeycomb acoustic superstructure is less than 50 mm, and the surface density is less than 5 kg / m².

[0051] A honeycomb acoustic superstructure is made according to the method, and the average sound absorption coefficient of the honeycomb acoustic superstructure in the frequency range of 400-4000 Hz is not less than 0.8, the weighted sound reduction index is not less than 20 dB, and the total thickness is not more than 1 / 20 of the lowest sound absorption wavelength.

[0052] In one embodiment, a preparation method of the sound absorption and insulation integrated honeycomb acoustic superstructure includes the following steps: first, differentially cutting honeycomb plates with specific thicknesses along the thickness direction to form a plurality of honeycomb bases 2 arranged side by side and having different thicknesses; then, laying a perforated plate 1 with non-uniform holes on the front end of the honeycomb base 2; then, for each honeycomb base 2 of a certain thickness except the honeycomb base 2 with the largest thickness, arranging an intermediate cover plate 3 with sound wave passing holes on the rear end thereof; then, selecting a group of honeycomb plates with different thicknesses, cutting the interiors thereof, forming a large volume back cavity 4 adapted to each intermediate cover plate 3 by combining the spaces of a plurality of honeycomb cells, and installing the back cavity 4 at the rear end of the intermediate cover plate 3; finally, laying an overall cover plate at the end of the back cavity 4; and tightly connecting the perforated plate 1, the honeycomb base 2, the intermediate cover plate 3, the back cavity 4, and the overall cover plate by means of a bonding process, thereby forming the sound absorption and insulation integrated honeycomb acoustic superstructure. Each honeycomb base 2 with a certain thickness contains at least two honeycomb cells, and the number of holes in the perforated plate 1 corresponding to each honeycomb cell is in a gradient distribution. The radii of all the holes corresponding to one honeycomb cell are the same, and the radii of the holes corresponding to different honeycomb cells can be the same or different. The thicknesses of each intermediate cover plate 3 are the same, the positions of the holes in each intermediate cover plate 3 are coaxial with the center of one honeycomb cell in the corresponding honeycomb base 2, and the noise reduction effect of the honeycomb acoustic superstructure in the low frequency band can be adjusted by adjusting the size of the holes. The rear end of each intermediate cover plate 3 is provided with an independent back cavity 4, and the thickness of each back cavity 4 is determined as follows: taking the thickness of the honeycomb base 2 with the largest thickness as a reference value, subtracting the thickness of the honeycomb base 2 corresponding to the back cavity 4, and then subtracting the thickness of the intermediate cover plate 3, and the difference is the thickness of the back cavity 4. The honeycomb acoustic superstructure comprehensively utilizes a plurality of methods for widening the frequency band, forms a honeycomb supercell structure by connecting a plurality of honeycomb cell structures with the same thickness but different numbers of holes in parallel, can achieve the noise reduction effect in a certain frequency band range, further connects a plurality of honeycomb supercell structures with different thicknesses in parallel to further widen the working frequency band of the structure, and further utilizes the low frequency resonance enhancement mechanism of the back cavity 4 to improve the noise reduction effect in the low frequency band. Through the synergistic sound absorption mechanism of the honeycomb acoustic superstructure, the honeycomb acoustic superstructure can simultaneously exhibit excellent sound insulation performance, thereby realizing the functional integration of sound absorption and sound insulation. The thickness of the honeycomb acoustic superstructure is 1 / 23 of the lowest sound absorption wavelength, and the honeycomb acoustic superstructure has the advantage of thinness.

[0053] In one embodiment, the thicknesses of the perforated plate and the intermediate cover plate are 1 mm, and the thickness of the overall cover plate is 1.5 mm. Figure 2A detailed schematic diagram of the sound absorption and insulation integrated honeycomb acoustic superstructure in the embodiment is given. Specifically, it is composed of four honeycomb supercell structures with different thicknesses, each of which is composed of a perforated plate, a honeycomb matrix and an intermediate cover plate. In this embodiment, the thicknesses of the honeycomb matrices of the four honeycomb supercell structures are 5 mm, 10 mm, 20 mm and 47 mm respectively. Therefore, the total thickness of the sound absorption and insulation integrated honeycomb acoustic superstructure is 49.5 mm. For the honeycomb supercell structure, it is composed of six honeycomb unit cell structures with the same thickness, but the number of openings of the perforated plate corresponding to each honeycomb unit cell structure is different. The number of openings of the perforated plate corresponding to the six honeycomb unit cell structures is 1, 2, 3, 4, 5 and 6 respectively, and the inner cavity side length of each honeycomb unit cell structure is 8 mm. Since the thicknesses of the four honeycomb supercell structures are different, the back cavity behind the intermediate cover plate of the honeycomb supercell structure can be fully utilized. This part can be divided into three back cavities, i.e. the back cavity of the honeycomb supercell structure containing a 5 mm thick honeycomb matrix, the back cavity of the honeycomb supercell structure containing a 10 mm thick honeycomb matrix and the back cavity of the honeycomb supercell structure containing a 20 mm thick honeycomb matrix. The back cavity thicknesses of them are 42 mm, 37 mm and 27 mm respectively, and the cross-sectional area of each back cavity is consistent with the cross-sectional area of each honeycomb supercell structure. By opening holes in the intermediate cover plate, sound waves can enter the back cavity. The position of the hole opened in the intermediate cover plate corresponds to the honeycomb unit cell structure with 6 holes in each honeycomb supercell structure. Such a design fully utilizes the space of the structure, and the large back cavity can improve the sound absorption effect of the overall structure at low frequencies.

[0054] attached Figure 3 The radius parameters of the holes in the perforated plate and the intermediate cover plate in the sound absorption and insulation integrated honeycomb superstructure are given. In the perforated plate, except that the opening radius of the honeycomb unit cell structure with 1 hole in the honeycomb supercell structure containing a 47 mm thick honeycomb matrix is 1 mm, the opening radius of the rest of the perforated plate is 0.9 mm. The opening radius of the intermediate cover plate corresponding to the honeycomb supercell structure containing a 5 mm thick honeycomb matrix is 1.5 mm, the opening radius of the intermediate cover plate corresponding to the honeycomb supercell structure containing a 10 mm thick honeycomb matrix is 2.5 mm, and the opening radius of the intermediate cover plate corresponding to the honeycomb supercell structure containing a 20 mm thick honeycomb matrix is 3.5 mm.

[0055] The sound absorption coefficient and sound insulation amount of the honeycomb acoustic superstructure are calculated by using the finite element software COMSOL Multiphysics. In the numerical model, the materials of the perforated plate, the intermediate cover plate and the overall cover plate are resin, the materials of the honeycomb matrix and the back cavity plate are aluminum alloy, the Young's modulus of the resin is 2.5 + 0.125i GPa, and the density is 1200 kg / m3 The Poisson's ratio is 0.41, the Young's modulus of the aluminum alloy is 72 + 3.6i GPa, and the density is 2800 kg / m³. 3 The Poisson's ratio is 0.27, and the honeycomb wall thickness is 0.1 mm. The calculation results are attached. Figure 4a and attached Figure 4b As shown, it can be observed that, regarding the sound absorption coefficient, the honeycomb acoustic metastructure can produce a continuous sound absorption effect in the 300-4000 Hz range, and its sound absorption coefficient can reach above 0.8 at multiple frequency calculation points. Regarding the sound insulation, the honeycomb acoustic metastructure can break the constraints of the mass law in the frequency band above 250 Hz. It is worth mentioning that the thickness of the honeycomb acoustic metastructure is 1 / 23 of the lowest sound absorption wavelength, and its theoretical surface density is 4.89 kg / m². 2 It has lightweight structural characteristics.

[0056] To facilitate sample fabrication, this implementation case study utilizes 3D printing technology to fabricate a large-size prototype of an integrated sound-absorbing and sound-insulating honeycomb acoustic superstructure. Photos of the prototype are attached. Figure 5a As shown, its horizontal dimensions are 830 mm × 830 mm, and its thickness is 49.5 mm. In the large-size sample, the perforated plate, honeycomb substrate, intermediate cover plate, back cavity, and integral cover plate are all made of resin. The experimental test results of the sound absorption and sound insulation effects of the large-size sample are attached. Figure 5b and attached Figure 5c As shown, the sound absorption coefficients of the large-sized sample at frequencies of 400 Hz, 500 Hz, 630 Hz, 800 Hz, 1000 Hz, 1250 Hz, 1600 Hz, 2000 Hz, 2500 Hz, 3150 Hz, and 4000 Hz are 0.96, 0.96, 0.96, 0.80, 0.70, 0.78, 0.87, 0.94, 0.80, 0.77, and 0.73, respectively. The average sound absorption coefficient at each point in one-third octave band of the 400-4000 Hz broadband range is 0.84, and it exhibits good stability within this frequency range. The weighted sound insulation of the large-sized sample in the 100-4000 Hz frequency range is 20.9 dB. Therefore, based on the combined sound absorption and sound insulation test results of large-size samples, it can be concluded that the integrated sound absorption and sound insulation honeycomb acoustic superstructure of the present invention can achieve a sound absorption and sound insulation performance of 49.5 mm thickness and 4.89 kg / m². 2The theoretical surface density of this structure provides good sound absorption and sound insulation effects over a wide frequency range, achieving an integrated design that combines sound absorption and sound insulation functions. Furthermore, the integrated sound absorption and sound insulation honeycomb acoustic superstructure of this invention features a simple structure, thin thickness, low surface density, and good noise reduction effect, making it suitable for a wide range of applications. It can be widely used in the roof and sidewalls of rail vehicles and other applications requiring sound absorption and insulation, demonstrating significant application value.

[0057] The present application assembles the honeycomb matrix, the perforated plate, the intermediate cover plate, the back cavity and the whole cover plate into a whole structure through a bonding process. The function integration design makes the structure have the dual functions of sound absorption and sound insulation, breaks through the limitation of traditional single function structure; the structure has strong stability, the honeycomb structure has excellent compression resistance and shear resistance, and is suitable for use as a load-bearing structure; the acoustic performance is excellent, and through the synergistic effect between multiple layers of structure, multiple resonance and dissipation of sound waves are realized; it is suitable for complex environment, has good mechanical strength and durability, and is suitable for dynamic environment applications such as rail vehicles, aerospace, etc. A plurality of supercell structures are formed by using honeycomb matrices of different thicknesses (such as 5mm, 10mm, 20mm, 47mm). The sound absorption frequency band is widened, different thicknesses correspond to different sound absorption frequency bands, so as to form a sound absorption peak in a wide frequency range; the structure flexibility is enhanced, the honeycomb thickness distribution can be customized according to the target noise frequency band, and the design adaptability is improved; the single resonance limitation is avoided, a single thickness can only play a role in a certain frequency band, and the multi-thickness design makes it respond in the whole low frequency to medium-high frequency band; multi-purpose adaptation is supported, and it is suitable for composite noise environment in various application scenarios such as train roof and side wall. A plurality of honeycomb cells are arranged in the same honeycomb matrix, and the number of holes on the perforated plate corresponding to each cell is different (such as 1-6), forming a gradient distribution of perforation rate. The sound absorption response range is enhanced, different perforation rates cause different resonance and dissipation behaviors of incident sound waves in different honeycomb cells; the sound absorption bandwidth is widened, and through the parallel coupling effect, the overall sound absorption frequency band can be widened by the joint action of multiple honeycomb cells; the manufacturing difficulty is reduced, the perforation rate change is easy to control, which is conducive to large-scale production and quality consistency guarantee; the sound energy absorption path is optimized, and different hole numbers affect the propagation path and energy loss mode of sound waves in the honeycomb structure. Holes coaxial with the centers of the honeycomb cells are formed on the intermediate cover plate, and the hole diameters are adjusted according to the thickness of the honeycomb matrix (such as 1.5mm, 2.5mm, 3.5mm). The low-frequency sound absorption performance is enhanced, the sound wave frequency range entering the back cavity can be adjusted by adjusting the hole diameter; the frequency directional response is realized, different hole diameters correspond to the resonance enhancement of different frequencies, which is helpful to realize accurate noise reduction of target frequency band; the structure adjustability is improved, which is convenient for parameter optimization design according to different noise source characteristics. A large-volume back cavity is arranged at the rear end of the intermediate cover plate, and the resonance characteristics of the back cavity are used to enhance the absorption capacity of low-frequency sound waves. The low-frequency sound absorption effect is significantly improved, the back cavity acts as a low-frequency resonance cavity and can greatly enhance the sound absorption coefficient at a specific frequency; the sound absorption frequency band is expanded, the back cavity and the honeycomb matrix form a synergistic effect, so that the structure maintains good sound absorption performance in a wider frequency band; the structure space is fully utilized, the originally idle space is converted into a functional back cavity, and the space utilization rate is improved. The space of multiple honeycomb cells is combined to form a large-volume back cavity structure matched with the intermediate cover plate.The large volume back cavity can effectively excite low frequency resonance compared with a single small cavity, the structural compactness is enhanced, a larger back cavity volume is realized in a limited thickness to meet the design requirements of thin and light, the manufacturing feasibility is improved, the unified back cavity structure is convenient for processing and forming to improve production efficiency, the modular expansion is supported, the structural design is conducive to subsequent expansion and splicing, and is suitable for large-scale engineering applications. The components such as honeycomb matrix, cover plate and perforated plate can be selected from various materials such as paper-based, metal-based, ceramic-based or polymer materials. Different application scenarios are adapted to, the metal material is suitable for occasions with high strength requirements, the resin material is suitable for lightweight requirements, the performance and cost are balanced, the material combination can be flexibly selected according to the engineering budget and performance requirements, the structural durability is improved, some materials have fireproof, corrosion-resistant and moisture-proof properties, and are suitable for harsh environments, green manufacturing is promoted, and some materials can be recycled and reused, which meets the environmental protection development trend. The perforated plate, honeycomb matrix, intermediate cover plate, back cavity and overall cover plate are tightly connected by using an adhesive. The structural integrity is enhanced, the bonding ensures the tight combination between layers to prevent structural failure caused by looseness, the energy transfer is promoted, the bonding interface can realize good energy coupling in the sound wave propagation process, the structural stability is improved, the interlayer peeling phenomenon caused by temperature and humidity changes is avoided, and the manufacturing process is facilitated. The basic unit planar array is expanded to a large-size sample piece of 830 mm × 830 mm, and sound absorption and sound insulation tests are carried out in a reverberation chamber and a semi-anechoic chamber. The engineering feasibility is verified, the large-size sample piece shows that the structural design can be expanded to actual engineering applications, real performance data is obtained, the experimental results are closer to the actual use environment and have a high reference value, the advantages of traditional structures are compared, the measured average sound absorption coefficient reaches 0.84, the weighted sound reduction index reaches 20.9 dB, the performance superiority is verified, the sample piece production process is mature, and the feasibility basis for batch production is provided.

[0058] Although the embodiments of the present application are described above with reference to the drawings, the present application is not limited to the above-described specific embodiments and application fields, and the above-described specific embodiments are only illustrative and guiding, but not limiting. Those skilled in the art can make many forms under the guidance of the present specification and without departing from the scope protected by the claims of the present application, which all belong to the protection of the present application.

Claims

1. A method of sound absorption and sound insulation integrated cellular acoustic superstructure, characterized by, It comprises, The honeycomb plate is differentiated in thickness direction to form a plurality of parallel arranged honeycomb bases (2) with different thicknesses; The perforated plate (1) with non-uniform holes is laid on the front end of the honeycomb base (2); For each honeycomb base (2) with a thickness other than the thickest one, a middle cover plate (3) with sound wave passing holes is arranged at the rear end thereof; The inside of the honeycomb plate with different thicknesses is cut to form a back cavity (4) adapted to each middle cover plate (3) by combining the space of multiple honeycomb units, and the back cavity (4) is installed at the rear end of the middle cover plate (3); An overall cover plate (5) is laid at the end of the back cavity (4) to help the bonding process to tightly connect the perforated plate (1), the honeycomb base (2), the middle cover plate (3), the back cavity (4) and the overall cover plate (5) to form an integrated honeycomb acoustic superstructure.

2. The method of claim 1, wherein, Preferably, each honeycomb base (2) with a thickness contains at least two honeycomb units, and the number of holes in the perforated plate (1) corresponding to each honeycomb unit is in gradient distribution, and all the perforated radii corresponding to the same honeycomb unit are the same.

3. The method of claim 2, wherein, The perforated radii corresponding to different honeycomb units are the same or different.

4. The method of claim 1, wherein, The thickness of each middle cover plate (3) is the same, the position of the hole in each middle cover plate (3) is coaxial with the center of one of the honeycomb units in the corresponding honeycomb base (2), and the size of the hole is adjusted to adjust the noise reduction effect of the honeycomb acoustic superstructure in the low frequency band.

5. The method of claim 1, wherein, The rear end of each middle cover plate (3) is provided with an independent back cavity (4), and the thickness of each back cavity (4) is determined as follows: taking the thickness of the thickest honeycomb base (2) as a reference value, subtracting the thickness of the honeycomb base (2) corresponding to the back cavity (4), and then subtracting the thickness of the middle cover plate (3), the difference is the thickness of the back cavity (4).

6. The method of claim 1, wherein, The material of the honeycomb plate is selected from at least one of paper-based composite material, metal-based composite material and ceramic-based composite material, and the material of the perforated plate (1), the middle cover plate (3) and the overall cover plate (5) is selected from any one of metal, polymer material, composite material and inorganic non-metal.

7. The method of claim 1, wherein, The thickness of the honeycomb base is non-uniformly distributed, and at least two honeycomb bases with different thicknesses are included to form sound absorption responses in multiple working frequency bands.

8. The method of claim 1, wherein, The thickness of the honeycomb acoustic superstructure is 1 / 23 of the lowest sound absorption wavelength, the number of holes corresponding to each honeycomb unit in the perforated plate is not completely the same, and a perforation rate gradient distribution is formed to broaden the sound absorption band.

9. The method of claim 1, wherein, The thickness of the honeycomb acoustic superstructure is less than 50 mm, and the area density is less than 5 kg / m².

10. A cellular acoustic superstructure, characterized in that, It is made according to the method of any one of claims 1-9, the average sound absorption coefficient of the honeycomb acoustic superstructure in the frequency range of 400-4000 Hz is not less than 0.8, the weighted sound insulation quantity is not less than 20 dB, and the total thickness is not more than 1 / 20 of the lowest sound absorption wavelength.

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