An acoustic wave processing structure, its device and preparation method

Abstract

The present invention discloses an acoustic wave processing structure and its device and preparation method. The structure includes a base plate and a plurality of raised structures arranged on one side thereof. The raised structures include a plurality of structural units. The plurality of structural units are distributed in a direction parallel to the base plate. The structural units include a plurality of structural plates and two partitions. The structural plates are parallel to the base plate. The structural plates and the base plate are spaced apart. The partitions are perpendicular to the base plate. The plurality of structural plates are spaced apart in sequence in a direction perpendicular to the base plate. The two partitions are spaced apart in parallel. The plurality of structural plates are arranged between the two partitions. The two ends of the structural plates are respectively connected to the partitions. Each structural plate is provided with a slit or a through hole, and the slit or the through hole passes through the structural plate. The acoustic wave processing structure of the present invention can reduce the volume of the scatterer by multiples and maintain the diffusion properties of its sound waves, thereby improving the space utilization rate. The base plate is made of porous material and can be used with adjusting parts to adjust the spatial distance between the base plate and the surface to be installed, so that it also has a good sound wave absorption effect.

Description

Technical Field

[0001] The present invention relates to the field of spatial acoustic technology, and in particular, to an acoustic wave processing structure, its device and preparation method. Background Art

[0002] In scenarios with high requirements for acoustic environments, such as concert halls, cinemas, classrooms, and conference rooms, due to the relatively regular shape of the room, the indoor sound field is unevenly distributed, affecting the intuitive experience of listeners. Usually, acoustic decoration treatment is required for the interior. A common treatment method is to use acoustic diffusers to spread sound waves in all directions to obtain a more uniform sound field. At the same time, the control of the reverberation time of the room is also extremely important, and the requirements for the reverberation time are different in different application scenarios. For example, when giving a speech, in order to obtain clear information from the speaker, the reverberation time cannot be too long; while when performing a symphony, due to the need to reflect the momentum of the music, a relatively long reverberation time is required. However, after the room is built and the audience enters, the reverberation time is fixed and cannot be changed according to the different performance forms, making the performance effect not reach the best.

[0003] Currently, the commonly used acoustic diffuser is the Schroeder diffuser, which is composed of a series of grooves with the same width but different depths, and a thin plate grille is provided between the grooves. However, the current Schroeder diffuser has several obvious problems: one is that for the diffuser of low-frequency sound waves, according to the design requirements, the depth of the groove needs to reach half a wavelength, so the size is huge; the other is that the surface of the groove structure is uneven, causing the wall to be uneven, affecting the aesthetics and also easily interfering with the installation of other devices. For adjustable sound absorption / reflection bodies, the current structures often only have adjustable sound absorption / reflection functions, and their diffusion performance is not good. The reflected sound waves have obvious directivity, and additional large Schroeder diffusers need to be added to make the room sound field more uniform.

[0004] Therefore, in combination with the above existing technical problems, it is necessary to propose a new technical solution. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the object of the present invention is to provide a structure that combines an ultra-thin planar acoustic diffuser and an absorber. By setting a variety of different perforated plate arrays or slit plate arrays on a bottom plate, and designing and arranging the perforated plate arrays or slit plate arrays according to a certain rule to adjust the phase of the reflected wave, a broadband acoustic wave diffusion effect is achieved by designing the aperture or slit width, plate thickness, cavity size, overall thickness, etc. At the same time, the bottom plate can be made of porous material, and this structure can be adjustably installed on the wall surface and other installation surfaces. By controlling the distance between the bottom plate and the installation surface to be installed, it can also have two states of "diffusion" and "absorption". The specific solutions are as follows:

[0006] According to one aspect of the present invention, the present invention provides an acoustic wave processing structure, which includes a bottom plate and a plurality of protruding structures provided on one side of the bottom plate. Each of the protruding structures includes a plurality of structural units, and the plurality of structural units are distributed along a direction parallel to the bottom plate. Each of the structural units includes a plurality of structural plates and two partition plates. The structural plates are arranged parallel to the bottom plate, the structural plates are spaced apart from the bottom plate, the partition plates are arranged perpendicular to the bottom plate, the plurality of structural plates are sequentially spaced apart along a direction perpendicular to the bottom plate, the two partition plates are arranged parallel and spaced apart, the plurality of structural plates are arranged between the two partition plates, and two ends of the structural plates are respectively connected to the two partition plates. Each of the structural plates is provided with a slit or a plurality of through holes, and the slit or the through holes penetrate through the structural plates in a direction perpendicular to the bottom plate.

[0007] Further, within each of the protruding structures, the plurality of structural units are distributed along the width direction of the protruding structure, and two adjacent structural units share one of the partition plates.

[0008] Further, the width of the protruding structure is 1 / 2 of the wavelength of the highest frequency acoustic wave within the acoustic wave frequency band to be affected, and the thickness of the protruding structure is not greater than 1 / 2 of the wavelength of the lowest frequency acoustic wave within the acoustic wave frequency band to be affected.

[0009] Further, the length direction of the slit is consistent with the length direction of the protruding structure, and both ends in the length direction of the slit penetrate through both ends of the structural plate.

[0010] Further, the bottom plate and / or the protruding structure is a porous material, and the bottom plate and / or the protruding structure has rigidity.

[0011] According to another aspect of the present invention, the present invention further provides an acoustic wave processing device, which includes the above-mentioned acoustic wave processing structure, and further includes a connecting member and an adjusting member. The acoustic wave processing structure is rotatably installed on a surface to be installed through the connecting member, the side of the bottom plate away from the protruding structure faces the surface to be installed, and the adjusting member is arranged between the bottom plate and the surface to be installed. Adjusting the adjusting member can adjust the distance between the bottom plate and the surface to be installed.

[0012] Further, the adjusting member is arranged at one end of the bottom plate, and the adjusting member is arranged at the other end of the bottom plate.

[0013] According to another aspect of the present invention, the present invention further provides a preparation method for the above-mentioned acoustic wave processing structure, which includes the following steps:

[0014] A number of virtual grooves are arranged on the bottom plate according to the acoustic wave frequency band to which they are applied. The depths of the number of virtual grooves are arranged in a quadratic residue sequence, where the maximum groove depth is 1 / 2 of the wavelength of the lowest frequency acoustic wave within the acoustic wave frequency band to which they are applied, and the width of the virtual groove is 1 / 2 of the wavelength of the highest frequency acoustic wave within the acoustic wave frequency band to which they are applied; the convex structures are respectively arranged at positions corresponding to each virtual groove on one side of the bottom plate. The width of the convex structure is the same as the width of the virtual groove, the thicknesses of the number of convex structures in the direction perpendicular to the bottom plate are the same, and the thickness of the convex structure is not greater than the maximum groove depth.

[0015] Further, the calculation formula for the width of the virtual groove is as follows:

[0016]

[0017] The virtual grooves are distributed in one dimension on the bottom plate. The calculation formula for the depth of the nth virtual groove is as follows:

[0018] Or

[0019] S n =n 2 modN

[0020] The virtual grooves are distributed in two dimensions on the bottom plate. The calculation formula for the depth of the mth virtual groove in the nth row is as follows:

[0021]

[0022] S nm =(n 2 +m 2 )modN

[0023] Where D is the width of the virtual groove, c0 is the propagation speed of sound waves in air, f max is the highest frequency of the sound waves within the acoustic wave frequency band to which they are applied, λ min is the minimum wavelength of the sound waves within the acoustic wave frequency band to which they are applied; h n is the depth of the nth virtual groove, h nm is the depth of the mth virtual groove in the nth row, λ max is the maximum wavelength of the sound waves within the acoustic wave frequency band to which they are applied, N is a positive integer, and mod is to take the remainder.

[0024] Further, it is assumed that the direction parallel to the bottom plate is the x-axis direction, and the direction perpendicular to the bottom plate is the y-axis direction. The density and bulk modulus of the convex structure satisfy the following relationship:

[0025]

[0026] The propagation speed of the sound wave in the protruding structure satisfies the following relationship:

[0027]

[0028] Wherein, ρ is the density of the protrusion structure, K is the bulk modulus of the protrusion structure, ρ0 is the density of air, K0 is the bulk modulus of air, L is the thickness of the protrusion structure, and h is the depth of the virtual groove corresponding to the protrusion structure.

[0029] Furthermore, the thickness of the structural plate and the spaced cavities adjacent to the structural plate constitute a structural subunit, and the density of the protruding structure in a direction perpendicular to the base plate is controlled by adjusting the thickness of the structural plate, the width of the slit or the aperture of the through hole, and the thickness of the structural subunit; the density of the protruding structure in a direction parallel to the base plate is controlled by adjusting the thickness of the structural plate and the thickness of the structural subunit; and the bulk modulus of the protruding structure is controlled by adjusting the duty cycle of the air in the protruding structure.

[0030] Compared with the prior art, the acoustic wave processing structure and the device and preparation method of the present application have at least one or more of the following beneficial effects:

[0031] (1) The acoustic wave processing structure of the present application combines the quadratic residue sequence and the transformation acoustic method. From the beginning of the design, the method of reducing the volume of the Schroeder scatterer by multiples is considered. The acoustic metamaterial is used to construct an acoustic unit structure with anisotropic density. That is, a convex structure composed of a plurality of different perforated plate arrays or slot plate arrays designed or arranged in a certain pattern is provided on one side of the bottom plate to be equivalent to the groove in the prior art, and the phase of the reflected wave is adjusted. On the one hand, the overall design can be made into a flat structure. On the other hand, the aperture or slot width, plate thickness, cavity size, overall thickness, etc. in the convex structure can be designed to achieve a broadband sound wave diffusion effect, and an ultra-thin broadband acoustic scatterer can be realized as a whole.

[0032] (2) The acoustic wave processing structure of the present application can achieve the same scattering effect on the sound waves while reducing the volume of the acoustic scatterer, i.e., the acoustic wave processing structure, by multiples, thereby improving the space utilization rate;

[0033] (3) The convex structure of the acoustic wave treatment structure of the present application can be made of hard material or porous material to form an air flow channel with multiple cavities interlaced and connected to the outside air;

[0034] (4) The acoustic wave processing structure of the present application, whose bottom plate is used to support the raised structure on the upper part, plays the role of reflecting the acoustic waves, and has the function of realizing modular installation;

[0035] (5) The acoustic wave processing device of the present application utilizes the acoustic wave processing structure of the present application. A back reflection layer is constructed with a bottom plate made of porous material, and in cooperation with connecting components such as hinges and adjusting components such as folding adjustable support switches, the distance between the bottom plate and the installation surface such as the wall can be adjusted. Thus, the state of the bottom plate can be adjusted to two situations: "close to the installation surface" and "having a cavity with the installation surface", enabling the realization of two states of "scattering and diffusion" and "sound absorption" on the same acoustic wave processing structure. Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the acoustic wave processing structure provided by an embodiment of the present application;

[0037] Figure 2 It is a partial structural diagram of the convex structure provided by an embodiment of the present application;

[0038] Figure 3 It is a comparison diagram of the sound velocity reflected by three convex structures provided by an embodiment of the present application and the required sound velocity calculated by transforming the acoustic method;

[0039] Figure 4 It is a comparison diagram of the scattering sound fields of three scatterers provided by an embodiment of the present application at 2000 Hz;

[0040] Figure 5 It is a schematic structural diagram of the acoustic wave processing device provided by an embodiment of the present application;

[0041] Figure 6 It is a comparison diagram of the sound absorption coefficients of the acoustic wave processing device in the "closed" state and the "opened 30°" state at 100 Hz - 5000 Hz provided by an embodiment of the present application;

[0042] Figure 7 It is a comparison diagram of the scattering effects of the acoustic wave processing device in the "closed" state at three frequencies of 1.5 kHz, 3 kHz, and 4.5 kHz.

[0043] Among them, 1 - bottom plate, 2 - convex structure, 21 - structural unit, 211 - structural plate, 212 - partition board, 213 - slit, 214 - spaced cavity, 3 - connecting component, 4 - adjusting component, w - slit width, t - structural plate thickness, a - structural subunit thickness, D - convex structure width, L - convex structure thickness. Detailed Embodiment

[0044] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in combination with the drawings and preferred embodiments, details the specific embodiments, structures, features, and their effects according to the present invention.

[0045] Embodiment

[0046] Figure 1 Schematic structural diagram of the acoustic wave processing structure provided by the embodiment of the present application; Figure 2 Partial structural diagram of the convex structure provided by the embodiment of the present application; Figure 3 Comparison diagram of the sound velocity reflected by three convex structures provided by the embodiment of the present application and the required sound velocity calculated by the transformed acoustic method; Figure 4 Comparison diagram of the scattering sound fields of three scatterers at 2000 Hz provided by the embodiment of the present application; Figure 5 Schematic structural diagram of the acoustic wave processing device provided by the embodiment of the present application; Figure 6 Comparison diagram of the sound absorption coefficients of the acoustic wave processing device in the "closed" state and the "opened 30°" state at 100 Hz - 5000 Hz provided by the embodiment of the present application; Figure 7 Comparison diagram of the scattering effects of the acoustic wave processing device in the "closed" state at three frequencies of 1.5 kHz, 3 kHz, and 4.5 kHz.

[0047] This embodiment provides an acoustic wave processing structure, which includes a bottom plate 1 and a plurality of convex structures 2 arranged on one side of the bottom plate 1, as Figure 1 shown. Each of the convex structures 2 includes a plurality of structural units 21, and the plurality of structural units 21 are distributed along a direction parallel to the bottom plate 1. Each of the structural units 21 includes a plurality of structural plates 211 and two partition plates 212. The structural plates 211 are arranged parallel to the bottom plate 1, the structural plates 211 are spaced apart from the bottom plate 1, the partition plates 212 are arranged perpendicular to the bottom plate 1, the plurality of structural plates 211 are sequentially spaced apart along a direction perpendicular to the bottom plate 1, the two partition plates 212 are arranged parallel and spaced apart, the plurality of structural plates 211 are arranged between the two partition plates 212, and both ends of each of the structural plates 211 are connected to the two partition plates 212. Each of the structural plates 211 is provided with a slit 213 or a plurality of through holes, and the slit 213 or the through holes penetrate the structural plate 211 in a direction perpendicular to the bottom plate 1. Inside each of the convex structures 2, the plurality of structural units 21 are distributed along the width direction of the convex structure 2, and two adjacent structural units 21 share one of the partition plates 212, as Figure 2As shown in the figure. The structural plate 211 adaptively shown in the figure is a slotted plate, that is, slits 213 are formed in the structural plate 211. The length direction of the slits 213 is the same as the length direction of the convex structure 2, and both ends of the length direction of the slits 213 penetrate through both ends of the structural plate 211. Of course, the structural plate 211 can also be a perforated plate, that is, by forming a plurality of through holes in the structural plate 211, the same effect as that of the slits 213 can also be achieved. It should be noted that the shape, quantity, arrangement and size of the through holes are not limited and can be designed and adjusted according to design requirements. This structure is relatively simple and will not be elaborated here.

[0048] In a further embodiment, the width of the convex structure 2 is 1 / 2 of the wavelength of the highest frequency sound wave in the acting sound wave frequency band. The thickness of the convex structure 2 is not greater than 1 / 2 of the wavelength of the lowest frequency sound wave in the acting sound wave frequency band. Preferably, the thickness of the convex structure 2 is 1 / 4 of the wavelength of the lowest frequency sound wave in the acting sound wave frequency band.

[0049] In a further embodiment, the bottom plate 1 can be made of a hard material such as metal, plastic or porous material, so as to have a certain rigidity, so as to support the convex structure 2 arranged thereon. The convex structure 2 can also be made of a hard material such as metal, plastic or porous material.

[0050] This embodiment also provides a preparation method of the above-mentioned sound wave processing structure, which includes three steps: the first is to arrange virtual grooves according to the quadratic residue sequence, the second is to use the transformation acoustics method to design a structure with a uniform thickness, and the third is to use the homogenization method to design acoustic metamaterials and realize the plane scatterer. The quantity of the convex structures 2 is determined according to the design result of the quadratic residue sequence. The thickness of the convex structure 2 is designed according to the transformation acoustics method. Specifically:

[0051] First, in the first step, a plurality of virtual grooves are arranged on the bottom plate 1 according to the acting sound wave frequency band. The depths of the plurality of virtual grooves are arranged in a quadratic residue sequence. The maximum groove depth is 1 / 2 of the wavelength of the lowest frequency sound wave in the acting sound wave frequency band. The width of the virtual groove is 1 / 2 of the wavelength of the highest frequency sound wave in the acting sound wave frequency band.

[0052] The calculation formula for the width of the virtual groove is as follows:

[0053] Among them, there are two distribution methods of the virtual grooves on the bottom plate 1, one is one-dimensional distribution and the other is two-dimensional distribution. The so-called one-dimensional distribution is linear distribution, and the two-dimensional distribution is planar distribution.

[0054] When the virtual grooves are distributed in one dimension on the bottom plate 1, the calculation formula for the depth of the nth virtual groove is as follows:

[0055]

[0056] S n = n 2 mod N

[0057] When the virtual grooves are distributed in two dimensions on the bottom plate 1, the calculation formula for the depth of the mth virtual groove in the nth row is as follows:

[0058]

[0059] S nm = (n 2 + m 2 ) mod N

[0060] where D is the width of the virtual groove, c0 is the propagation speed of sound in air, f max is the highest frequency of the sound waves within the frequency band of the applied sound waves, λ min is the minimum wavelength of the sound waves within the frequency band of the applied sound waves; h n is the depth of the nth virtual groove, h nm is the depth of the mth virtual groove in the nth row, λ max is the maximum wavelength of the sound waves within the frequency band of the applied sound waves, N is a positive integer, and mod is to take the remainder.

[0061] Secondly, the second step is to use transformation acoustics to unify the structural thickness and achieve a multiple reduction in thickness. Its main principle is to reflect the change in sound wave propagation caused by the distortion of space in the distribution of the sound field material parameters. The effects of both on the sound field are completely equivalent. That is, after filling a certain material in the actual space, in the view of an external observer, the sound waves propagate in another virtual space (filled with a classical medium) generally. This method is based on coordinate transformation methods such as compression, stretching, or rotation of the original sound field, and reflects the effect of the coordinate transformation in the acoustic material parameters, thereby achieving the control of the sound field. The specific relationship is:

[0062]

[0063] where ρ0 and K0 are the density and bulk modulus of air, and A is the Jacobian matrix that maps the actual space and the virtual space to each other The calculated ρ and K are the material parameters required to be filled in the actual space.

[0064] Specifically, the above-mentioned convex structures 2 are respectively arranged on one side of the bottom plate 1 corresponding to the positions of each virtual groove to equivalently correspond to the virtual grooves. The width of the convex structure 2 is the same as the width of the virtual groove. The thicknesses of several convex structures 2 in the direction perpendicular to the bottom plate 1 are the same, and the thickness of the convex structure 2 is not greater than the maximum groove depth. Set the direction parallel to the bottom plate 1 as the x-axis direction, and the direction perpendicular to the bottom plate 1 as the y-axis direction, as Figure 1 shown. The density and bulk modulus of the convex structure 2 need to satisfy the following relationship:

[0065]

[0066] The sound wave propagation speed in the convex structure 2 satisfies an anisotropic relationship, specifically as follows:

[0067]

[0068] where ρ is the density of the convex structure 2, K is the bulk modulus of the convex structure 2, ρ0 is the density of air, K0 is the bulk modulus of air, L is the thickness of the convex structure 2, and h is the depth of the virtual groove corresponding to the convex structure 2.

[0069] Finally, in the third step, the homogenization method, the energy band theory, or the parameter retrieval method is used to design the acoustic metamaterial so that the equivalent parameters it exhibits conform to the results designed by transformation acoustics, and the planar scatterer is realized. The acoustic metamaterial is used to realize a medium with anisotropic density, thereby preparing the planar scatterer. The acoustic metamaterial with anisotropic density can be realized by using a perforated plate array or a slotted plate array. Specifically, the thickness of the structural plate 211 and the adjacent spaced cavity 214 form a structural subunit. By adjusting the thickness of the structural plate 211, the slit width of the slit 213 or the aperture of the through hole, and the thickness of the structural subunit, the density of the convex structure 2 in the direction perpendicular to the bottom plate 1 is controlled. The smaller the slit width of the slit 213 or the aperture of the through hole, and the larger the filling rate of the structural plate 211 in the structural subunit, the greater the density of the convex structure 2 in the direction perpendicular to the bottom plate 1, that is, a proportional relationship. By adjusting the thickness of the structural plate 211 and the thickness of the structural subunit, the density of the convex structure 2 in the direction parallel to the bottom plate 1 is controlled. The larger the filling rate of the structural plate 211 in the structural subunit, the greater the density of the convex structure 2 in the direction parallel to the bottom plate 1, that is, a proportional relationship. By adjusting the duty ratio of the air in the convex structure 2, the bulk modulus of the convex structure 2 is controlled. The smaller the duty ratio of the air in the convex structure 2, the greater the bulk modulus of the convex structure 2, that is, an inverse proportional relationship.

[0070] Next, the above scheme will be further illustrated by examples.

[0071] Example 1:

[0072] In this example, both the bottom plate 1 and the convex structure 2 are made of 3D printed resin. The bottom plate 1 has a thickness of 2.5 mm and is attached to the wall to play a role in reflecting sound waves.

[0073] The convex structure 2 is arranged on the bottom plate 1. First, according to the frequency band of the sound wave to be diffused, the depth of the virtual groove is designed in combination with the quadratic residue sequence. Taking a one-dimensional Schroeder scatterer as an example, if it is necessary to diffuse sound waves in the range of 1700 Hz to 3400 Hz, the deepest groove thereof needs about 10 cm, and the width is about D = 5 cm. When the quadratic residue sequence N = 7 is selected to calculate the depth arrangement of the virtual groove, as shown in Table 1:

[0074] Table 1

[0075] The nth virtual groove 1 2 3 4 5 6 7 8 9 … Virtual groove depth h (cm) 2.5 10 5 5 10 2.5 0 2.5 10 …

[0076] As can be seen from Table 1, there are 4 types of virtual grooves with depth distributions. Using the transformation acoustics method, a filling layer with a thickness L = 5 cm is designed on one side of the bottom plate 1, and materials are filled in the 5 cm filling layer to form the convex structure 2, so that the groove depths of h = 0 cm, 2.5 cm, 5 cm and 10 cm are respectively simulated, meeting the requirement of nearly halving the size. According to the transformation acoustics calculation, the parameters of the 4 types of convex structures 2 are as shown in Table 2:

[0077] Table 2

[0078]

[0079] Four different slotted plates are used to implement the above sound velocity distribution. Considering the working frequency band, each unit should be in sub-wavelength (<λ / 10) to work stably. Therefore, each convex structure 2 with a width D = 5 cm is separated into two identical structural units 21 on the left and right, and a hard partition 212 with a thickness of 1 mm is used for separation in the middle. The partition 212 is also made of resin. The types of the convex structure 2 and the specific dimensions of the structural unit 21 are as shown in Table 3:

[0080] Table 3

[0081] Types of raised structures 1 (0 cm) 2 (2.5 cm) 3 (5 cm) 4 (10 cm) a (cm) 5 1 1 1 t (cm) No structure 0.5 0.5 0.6 w (cm) No structure 0.7 0.3 0.1

[0082] The comparison between the sound velocity reflected by the designed metamaterial structure, i.e., the convex structure 2, and the required sound velocity calculated by the transformation acoustics is as Figure 3 shown. It can be seen that the sound velocities exhibited by the three structures match the sound velocity calculated by the transformation acoustics. And this structure is broadband effective and can meet the design requirements.

[0083] Figure 4 It is a comparison diagram of the scattering sound fields of three kinds of scatterers at 2000 Hz. Among them, (a) is the sound field scattering effect diagram of the acoustic wave processing structure designed in this example, that is, the metamaterial planar scatterer with a thickness of 5 cm. (b) is the sound field scattering effect diagram of the commonly used Schroeder scatterer with a thickness of 10 cm. (c) is the sound field scattering effect diagram of the commonly used Schroeder scatterer with a thickness of 5 cm. As can be seen from the figure, the 5-cm-thick metamaterial planar scatterer designed in this example has the same effect as the 10-cm-thick Schroeder scatterer. Its reflected sound waves spread around, while the 5-cm-thick Schroeder scatterer cannot play the role of diffusing sound waves in this frequency band, and its reflected sound waves propagate upward, without good diffusion performance. Therefore, the acoustic wave processing structure of this application can maintain its good performance while doubling the reduction of the structure size.

[0084] This embodiment also provides an acoustic wave processing device, which includes the above-mentioned acoustic wave processing structure, as well as a connecting member 3 and an adjusting member 4. As Figure 5 shown, the connecting member 3 is preferably a hinge. The adjusting member 4 is preferably a foldable and adjustable support switch. The adjusting member 4 is arranged at one end of the bottom plate 1, and the adjusting member 4 is arranged at the other end of the bottom plate 1. The acoustic wave processing structure is rotatably installed on the wall or other installation surfaces through the connecting member 3, and at the same time, it can prevent the acoustic wave processing structure from shifting. The side of the bottom plate 1 away from the convex structure 2 faces the installation surface, and the adjusting member 4 is arranged between the bottom plate 1 and the installation surface. Adjusting the adjusting member 4 can adjust the distance between the bottom plate 1 and the installation surface. In specific implementation, the adjusting member 4 such as the foldable and adjustable support switch can lift one end of the bottom plate 1 by a certain angle, or contract to make the bottom plate 1 as close to the wall as possible to achieve the switch function. That is, the state of the bottom plate 1 is adjusted to two situations of "closely attached to the wall" and "having a cavity with the wall", corresponding to two states of "diffusion" and "absorption" respectively.

[0085] Next, the above scheme will be further described through examples.

[0086] Example 2:

[0087] In this example, the bottom plate 1 is a 9-mm standard board produced by Baijiali, with a weight of 1900 kg / m 2 . The convex structure 2 is made of 3D-printed resin.

[0088] The left end of the bottom plate 1 is connected to the hinge and fixed to the wall, and the right end is connected to the foldable and adjustable support switch, and the lower end of the switch is also fixed to the wall.

[0089] When the adjustable support switch is in the "closed" state, the bottom plate 1 is in close contact with the wall, acting as a hard boundary to reflect sound waves. When the adjustable support switch is in the "open" state, there is a cavity between the bottom plate 1 and the wall, and the whole is in the "absorption" mode at this time.

[0090] The convex structure 2 is arranged on the bottom plate 1. First, according to the frequency band of the sound wave to be diffused, the depth of the virtual groove is designed in combination with the quadratic residue sequence. Taking a one-dimensional Schroeder scatterer as an example, if the sound wave in the range of 1700 Hz to 3400 Hz is to be diffused, the deepest groove needs about 10 cm, and the width is about D = 5 cm. When the quadratic residue sequence N = 7 is selected to calculate the depth arrangement of the virtual groove, as shown in Table 1:

[0091] Table 4

[0092] The nth virtual groove 1 2 3 4 5 6 7 8 9 … Virtual groove depth h (cm) 2.5 10 5 5 10 2.5 0 2.5 10 …

[0093] According to Table 4, it can be seen that there are 4 kinds of virtual grooves with depth distributions. Using the transformation acoustics method, a filling layer with a thickness L = 5 cm is designed on one side of the bottom plate 1, and materials are filled in the 5 cm filling layer to form the convex structure 2, so that the groove depths of h = 0 cm, 2.5 cm, 5 cm and 10 cm are respectively simulated, meeting the requirement of reducing the size by nearly half. According to the transformation acoustics calculation, the parameters of the 4 kinds of convex structures 2 are as shown in Table 5:

[0094] Table 5

[0095]

[0096] Four different slotted plates are used to realize the above sound velocity distribution. Considering the operating frequency band, each unit should be in sub-wavelength (<λ / 10) to work stably. Therefore, each convex structure 2 with a width D = 5 cm is divided into two identical structural units 21 on the left and right, and separated by a hard partition 212 with a thickness of 1 mm in the middle. The partition 212 is also made of resin. The types of the convex structure 2 and the specific dimensions of the structural unit 21 are as shown in Table 6:

[0097] Table 6

[0098] Types of raised structures 1 (0 cm) 2 (2.5 cm) 3 (5 cm) 4 (10 cm) a (cm) 5 1 1 1 t (cm) No structure 0.5 0.5 0.6 w (cm) No structure 0.7 0.3 0.1

[0099] Figure 6 It is the comparison chart of the sound absorption coefficients in the "closed" state and the "opened 30°" state for 100 Hz - 5000 Hz. The square line is the structural sound absorption coefficient in the "closed" case, and the dot line is the structural sound absorption coefficient in the "opened 30°" case. It can be seen that in the "opened 30°" case, the low-frequency sound absorption coefficient is greatly improved as a whole. By opening and closing the structure, the control of the sound absorption coefficient can be realized.

[0100] Figure 7 When the structure is in the "closed" state, the scattering effects of the structure at three frequencies of 1.5 kHz, 3 kHz, and 4.5 kHz are shown in the figure. It can be seen that due to the quadratic residue arrangement of the structure distribution, its scattering effect is more chaotic in this frequency band, without obvious directivity, and has good diffusion performance. Moreover, the planar scatterer made of metamaterials, that is, the convex structure 2, can operate at a low frequency of 1.5 kHz under the condition of a thickness of about 5 cm, which has the same effect as a Schroeder scatterer with a thickness of 10 cm, and the reflected sound waves spread around. Therefore, this structure can maintain its good performance while reducing the structure size by several times, and at the same time has the function of adjustable sound absorption coefficient.

[0101] Compared with the prior art, the acoustic wave processing structure, its device and preparation method of the present application have at least one or more of the following beneficial effects:

[0102] (1) For the acoustic wave processing structure of the present application, it combines the quadratic residue sequence and the transformation acoustics method, and considers the method of reducing the volume of the Schroeder scatterer by several times from the beginning of the design. It uses acoustic metamaterials to construct an acoustic unit structure with anisotropic density, that is, by setting a convex structure composed of a plurality of different perforated plate arrays or slotted plate arrays designed or arranged according to certain rules on one side of the bottom plate to be equivalent to the groove in the prior art, and adjusting the phase of the reflected wave. On the one hand, it can make the overall design a flat structure, and on the other hand, it can design the aperture or slot width, plate thickness, cavity size, overall thickness, etc. in the convex structure, so as to achieve a wide-frequency acoustic wave diffusion effect, and overall, an ultra-thin wide-frequency acoustic scatterer can be realized;

[0103] (2) For the acoustic wave processing structure of the present application, it can reduce the volume of the acoustic scatterer, that is, the acoustic wave processing structure, by several times while maintaining the same scattering effect on the acoustic wave, and improve the space utilization rate;

[0104] (3) For the acoustic wave processing structure of the present application, its convex structure can be composed of a hard material or a porous material to form a plurality of air flow channels with staggered cavities and connected to the outside air;

[0105] (4) For the acoustic wave processing structure of the present application, its bottom plate is used to support the upper convex structure, play a role in reflecting acoustic waves, and has the function of realizing modular installation;

[0106] (5) The acoustic wave processing device of the present application utilizes the acoustic wave processing structure of the present application. A back reflection layer is constructed using a bottom plate made of porous material, and in cooperation with connecting components such as hinges and adjusting components such as folding adjustable support switches, the distance between the bottom plate and the installation surface such as the wall can be adjusted. Thus, the state of the bottom plate can be adjusted to two situations: "close to the installation surface" and "having a cavity with the installation surface", enabling the realization of two states of "scattering and diffusion" and "sound absorption" on the same acoustic wave processing structure.

[0107] In this text, the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion. In addition to the listed elements, it may also include other elements not explicitly listed.

[0108] In this text, the orientation terms such as front, back, top, bottom, etc. are defined based on the positions of the components in the drawings and the relative positions between the components, solely for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the orientation terms should not limit the scope of protection claimed in the present application.

[0109] Without conflict, the above-mentioned embodiments and the features in the embodiments in this text can be combined with each other.

[0110] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An acoustic wave processing structure, characterized in that, It includes a bottom plate (1) and a plurality of convex structures (2) provided on one side of the bottom plate (1). Each of the convex structures (2) respectively includes a plurality of structural units (21). The plurality of structural units (21) are distributed along a direction parallel to the bottom plate (1). Each of the structural units (21) respectively includes a plurality of structural plates (211) and two partition plates (212). The structural plates (211) are arranged parallel to the bottom plate (1), and the structural plates (211) are spaced apart from the bottom plate (1). The partition plates (212) are arranged perpendicular to the bottom plate (1). The plurality of structural plates (211) are sequentially spaced apart along a direction perpendicular to the bottom plate (1). The two partition plates (212) are arranged in parallel and spaced apart. The plurality of structural plates (211) are arranged between the two partition plates (212). The two ends of the structural plates (211) are respectively connected to the two partition plates (212). Each of the structural plates (211) is provided with a slit (213) or a plurality of through holes. The slit (213) or the through holes penetrate the structural plates (211) in a direction perpendicular to the bottom plate (1). A plurality of virtual grooves are provided on the bottom plate (1). The depths of the plurality of virtual grooves are arranged in a quadratic residue sequence. The maximum groove depth is 1 / 2 of the wavelength of the lowest frequency sound wave in the sound wave frequency band to which it acts. The width of the virtual groove is 1 / 2 of the wavelength of the highest frequency sound wave in the sound wave frequency band to which it acts. Convex structures (2) are respectively provided at positions corresponding to each virtual groove on one side of the bottom plate (1) to equivalently represent the corresponding virtual grooves. The width of the convex structure (2) is the same as the width of the virtual groove. The thicknesses of the plurality of convex structures (2) in a direction perpendicular to the bottom plate (1) are the same, and the thickness of the convex structure (2) is not greater than the maximum groove depth. The calculation formula for the width of the virtual groove is as follows: The virtual grooves are arranged in a one-dimensional pattern on the bottom plate (1). The calculation formula for the depth of the nth virtual groove is as follows: S n = n 2 mod N; or The virtual grooves are arranged in a two-dimensional pattern on the bottom plate (1). The calculation formula for the depth of the mth virtual groove in the nth row is as follows: S mn = (n 2 + m 2 ) mod N, Wherein, D is the width of the virtual groove, c0 is the propagation speed of sound waves in air, f max is the highest frequency of the sound waves within the frequency band of the applied sound waves, λ min is the minimum wavelength of the sound waves within the frequency band of the applied sound waves; h n is the depth of the nth virtual groove, h nm is the depth of the mth virtual groove in the nth row, λ max is the maximum wavelength of the sound waves within the frequency band of the applied sound waves, N is a positive integer, and mod is the remainder operation.

2. The acoustic wave processing structure according to claim 1, wherein Within each of the convex structures (2), the plurality of structural units (21) are distributed along the width direction of the convex structure (2). Two adjacent structural units (21) share one partition plate (212).

3. The acoustic wave processing structure according to claim 2, wherein, The width of the convex structure (2) is 1 / 2 of the wavelength of the highest frequency sound wave in the sound wave frequency band to which it acts. The thickness of the convex structure (2) is not greater than 1 / 2 of the wavelength of the lowest frequency sound wave in the sound wave frequency band to which it acts.

4. The acoustic wave processing structure according to claim 2, wherein The length direction of the slit (213) is the same as the length direction of the convex structure (2). The two ends in the length direction of the slit (213) penetrate the two ends of the structural plates (211).

5. The acoustic wave processing structure according to claim 1, wherein The bottom plate (1) and / or the convex structure (2) is a porous material. The bottom plate (1) and / or the convex structure (2) has rigidity.

6. An acoustic wave processing device, characterized in that, It includes the acoustic wave processing structure described in any one of claims 1 to 5, and further includes a connecting member (3) and an adjusting member (4). The acoustic wave processing structure is rotatably mounted on the surface to be installed through the connecting member (3). The side of the bottom plate (1) away from the convex structure (2) faces the surface to be installed. The adjusting member (4) is arranged between the bottom plate (1) and the surface to be installed, and adjusting the adjusting member (4) can adjust the distance between the bottom plate (1) and the surface to be installed.

7. The acoustic wave processing device according to claim 6, characterized in that, The adjusting member (4) is arranged at one end of the bottom plate (1), and the adjusting member (4) is arranged at the other end of the bottom plate (1).

8. A method for preparing the acoustic wave processing structure according to any one of claims 1 to 5, characterized in that, It includes the following steps: Set a number of virtual grooves on the bottom plate (1) according to the acoustic wave frequency band to which it acts. The depths of the number of virtual grooves are arranged in a quadratic residue sequence. The maximum groove depth is 1 / 2 of the wavelength of the lowest frequency acoustic wave within the acoustic wave frequency band to which it acts. The width of the virtual groove is 1 / 2 of the wavelength of the highest frequency acoustic wave within the acoustic wave frequency band to which it acts; On one side of the bottom plate (1), convex structures (2) are respectively arranged at positions corresponding to each virtual groove. The width of the convex structure (2) is the same as the width of the virtual groove. The thicknesses of the number of convex structures (2) in the direction perpendicular to the bottom plate (1) are the same, and the thickness of the convex structure (2) is not greater than the maximum groove depth; The calculation formula for the width of the virtual groove is as follows: The virtual grooves are distributed in one dimension on the bottom plate (1). The calculation formula for the depth of the nth virtual groove is as follows: S n = n 2 mod N; or The virtual grooves are distributed in two dimensions on the bottom plate (1). The calculation formula for the depth of the mth virtual groove in the nth row is as follows: S nm =(n 2 +m 2 ) mod N, where D is the width of the virtual groove, c0 is the propagation speed of sound waves in air, f max is the highest frequency of the sound waves within the frequency band of the applied sound waves, λ min is the minimum wavelength of the sound waves within the frequency band of the applied sound waves; h n is the depth of the nth virtual groove, h nm is the depth of the mth virtual groove in the nth row, λ max is the maximum wavelength of the sound waves within the frequency band of the applied sound waves, N is a positive integer, and mod is the remainder operation; Set the direction parallel to the bottom plate (1) as the x-axis direction, and the direction perpendicular to the bottom plate (1) as the y-axis direction. The density and bulk modulus of the convex structure (2) satisfy the following relationship: The propagation speed of the acoustic wave in the convex structure (2) satisfies the following relationship: Where ρ is the density of the convex structure (2), K is the bulk modulus of the convex structure (2), ρ0 is the density of air, K0 is the bulk modulus of air, L is the thickness of the convex structure (2), and h is the depth of the virtual groove corresponding to the convex structure (2).

9. The preparation method of the acoustic wave processing structure according to claim 8, characterized in that, The thickness of the structural plate (211) and the adjacent spaced cavity (214) form a structural sub-unit. By adjusting the thickness of the structural plate (211), the slit width of the slit (213) or the aperture of the through hole, and the thickness of the structural sub-unit, the density of the convex structure (2) in the direction perpendicular to the bottom plate (1) is controlled. By adjusting the thickness of the structural plate (211) and the thickness of the structural sub-unit, the density of the convex structure (2) in the direction parallel to the bottom plate (1) is controlled. By adjusting the duty ratio of the air in the convex structure (2), the bulk modulus of the convex structure (2) is controlled.

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