An ultra-thin low-frequency sound-absorbing metasurface unit structure and its application

Abstract

The present invention relates to an ultra-thin low-frequency sound-absorbing metasurface unit structure and its application, which includes a perforated front panel, a coiled cavity, a first perforated plate and a second perforated plate. The perforated front panel has holes with an area accounting for 0.38% of the area of the unit panel, and the hole diameter is 7 mm. During use, the present invention only needs to be installed at the place where sound absorption treatment is required and fixed on the wall surface. The present invention proves that the ultra-thin low-frequency perfect sound-absorbing metasurface unit structure has excellent sound absorption performance when the thickness is 5.9 cm. The sound absorption coefficient of the first absorption peak is 0.99 at 95 Hz, the sound absorption coefficient of the second absorption peak is 0.99 at 270 Hz, and the sound absorption coefficient of the third absorption peak is 0.99 at 378 Hz. It is easy to clean, without any internal filling fiber materials, and is completely... Compared with the prior art, the present invention has the advantages of improving the low-frequency sound absorption effect, a reconfigurable structure, so that the sound absorption coefficient can be shifted to different frequencies, and has excellent environmental protection functions and applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of noise control equipment, and in particular to an ultra-thin low-frequency sound-absorbing metasurface unit structure and its application. Background Art

[0002] Since the Industrial Revolution in the 18th century, cities have developed rapidly and the population has increased sharply. However, due to the increase in population, the urban structure has begun to deteriorate. Architects and engineers have started to design high-rise buildings to control the deterioration of the urban structure caused by this centralization. However, these high-rise buildings have also brought some engineering design problems that must be solved. Noise is one of the main challenges faced by today's buildings. It has a negative impact on our health, so the prevention and control of noise are crucial.

[0003] In order to reduce noise, various acoustic materials and acoustic technologies have emerged in an endless stream. Achieving perfect low-frequency sound absorption using deep sub-wavelength structures is a challenging research field in acoustics.

[0004] Traditional materials, such as porous materials, can provide effective absorption of sound waves in the middle and high frequencies due to their inherent structural characteristics. Although some micro-perforated panels (MPP) show sufficient sound absorption effect at low frequencies, they need to be paired with a sufficiently deep air cavity to achieve this effect. Research on MPP structures has always been a popular direction in the field of noise control, and researchers have proposed many design ideas. For example, by using holes of different shapes such as different sizes, conical holes, ultra-micro holes, and inclined holes, the influence of changing the hole structure on the sound absorption performance is studied. Another example is that since it is desired to increase the acoustic impedance while reducing the weight, researchers have also tried to design MPP using lightweight thin plates. However, due to vibration problems, ultra-thin panels may also bring some problems, such as unexpected absorption peaks in the low-frequency range. In the research of cavity parameters, researchers have also studied the influence of modifying the cavity on acoustic characteristics by using cavities with multiple depths, irregular shapes, and embedded partitions. In order to overcome the limitations of single parameters, researchers have also carried out parallel, serial, and hybrid arrangements and combinations of MPP layers. In addition, there have been attempts to integrate porous materials, honeycomb cores, and Helmholtz resonators in MPP structures to utilize the different acoustic characteristics of each component to achieve sound absorption. However, controlling sound waves at the sub-wavelength scale remains a daunting task. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide an ultra-thin low-frequency sound-absorbing metasurface unit structure and its application. The ultra-thin low-frequency sound-absorbing metasurface unit structure has the advantages of being thin, low-frequency sound absorption, high sound absorption coefficient, simple device, easy to clean, etc., and can reduce the existing noise pollution.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] A kind of ultra-thin low-frequency sound-absorbing metamaterial surface unit structure, comprising a perforated front panel, a coiled cavity, a first perforated plate and a second perforated plate.

[0008] The perforated front panel is arranged at the front end of the coiled cavity, and holes are provided on the perforated front panel.

[0009] The first perforated plate is located inside the coiled cavity. The upper and lower ends of the first perforated plate are connected to the coiled cavity. The front end of the first perforated plate is connected to the perforated front panel. First holes are provided on the first perforated plate.

[0010] The second perforated plate is located inside the coiled cavity. The upper and lower ends of the second perforated plate are connected to the coiled cavity. The front end of the second perforated plate is connected to the perforated front panel. Second holes are provided on the second perforated plate.

[0011] In a usage mode of the present invention, the area of the holes is 0.38% of the area of the perforated front panel.

[0012] In a usage mode of the present invention, the aperture of the holes is 7 mm.

[0013] In a usage mode of the present invention, the area of the first holes is 0.57% of the area of the first perforated plate.

[0014] In a usage mode of the present invention, the aperture of the first holes is 3.5 mm.

[0015] In a usage mode of the present invention, the area of the second holes is 0.57% of the area of the second perforated plate.

[0016] In a usage mode of the present invention, the aperture of the second holes is 3.5 mm.

[0017] In a usage mode of the present invention, the first holes are close to the lower end of the first perforated plate, and the second holes are close to the upper end of the second perforated plate.

[0018] The coiled cavity is a rectangular structure. The distance from the first perforated plate to the left end of the coiled cavity is equal to the distance from the first perforated plate to the second perforated plate, which is equal to the distance from the second perforated plate to the right end of the coiled cavity.

[0019] The distance from the first holes to the lower end of the coiled cavity is equal to the distance from the second holes to the upper end of the coiled cavity.

[0020] In a usage mode of the present invention, the materials of the perforated front panel, the coiled cavity, the first perforated plate and the second perforated plate are all photosensitive resin.

[0021] In addition, the present invention also provides an application of an ultra-thin low-frequency sound-absorbing metasurface unit structure, and installs the above ultra-thin low-frequency perfect sound-absorbing metasurface unit structure on the inner wall surface of a place that needs sound-absorbing treatment.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] 1. Compared with traditional sound-absorbing devices of equal thickness, the ultra-thin low-frequency perfect sound-absorbing metasurface unit structure provided by the present invention can achieve high- and low-frequency sound absorption, can be completely recycled, and has the advantages of easy cleaning, high temperature resistance, no internal filling fiber materials, etc., completely avoiding the problem of secondary pollution;

[0024] 2. The ultra-thin low-frequency perfect sound-absorbing metasurface unit structure provided by the present invention has excellent environmental protection functions, is easy to install, has a simple device, is easy to process, is ultrathin, light and portable, and can be applied to various forms of machine noise and most other noise sources, and has a good noise reduction effect;

[0025] 3. The present invention has the advantage of significantly improving the low-frequency sound absorption coefficient, and it can be proved that the sound absorption performance is excellent when the thickness is 5.9 cm. The sound absorption coefficient of the first absorption peak is 0.99 at 95 Hz, the sound absorption coefficient of the second absorption peak is 0.99 at 270 Hz, and the sound absorption coefficient of the third absorption peak is 0.99 at 378 Hz;

[0026] 4. The present invention has the advantages of improving the low-frequency sound absorption effect and a reconfigurable structure, so the sound absorption coefficient can be shifted to different frequencies and has excellent environmental protection functions. Description of the Drawings

[0027] Figure 1 It is a schematic external structure diagram of the ultra-thin low-frequency perfect sound-absorbing metasurface unit structure in the embodiment;

[0028] Figure 2 It is a schematic internal structure diagram of the ultra-thin low-frequency perfect sound-absorbing metasurface unit structure in the embodiment;

[0029] Figure 3 It is a schematic curve diagram of the sound absorption coefficient principle of the ultra-thin low-frequency perfect sound-absorbing metasurface unit structure in the embodiment;

[0030] Figure 4 It is a schematic curve diagram of the sound absorption coefficient principle of the ultra-thin low-frequency perfect sound-absorbing metasurface unit structure in the embodiment.

[0031] Explanation of the reference numerals in the drawings: 1, perforated front panel; 2, coiled cavity; 3, first perforated plate; 4, second perforated plate; 5, hole; 6, first hole; 7, second hole. Detailed Embodiments

[0032] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0033] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Embodiment 1

[0036] Refer to Figure 1 and Figure 2 , this embodiment provides a thin and low-frequency sound-absorbing metamaterial surface unit structure, including a perforated front panel 1, a coiled cavity 2, a first perforated plate 3, and a second perforated plate 4.

[0037] The perforated front panel 1 is arranged at the front end of the coiled cavity 2, and holes 5 are provided on the perforated front panel 1.

[0038] The first perforated plate 3 is located inside the coiled cavity 2. The upper and lower ends of the first perforated plate 3 are connected to the coiled cavity 2. The front end of the first perforated plate 3 is connected to the perforated front panel 1, and first holes 6 are provided on the first perforated plate 3.

[0039] The second perforated plate 4 is located inside the coiled cavity 2. The upper and lower ends of the second perforated plate 4 are connected to the coiled cavity 2. The front end of the second perforated plate 4 is connected to the perforated front panel 1, and second holes 7 are provided on the second perforated plate 4.

[0040] In this embodiment, the area of the holes 5 is 0.38% of the area of the perforated front panel 1.

[0041] In this embodiment, the aperture of the holes 5 is 7 mm.

[0042] In this embodiment, the area of the first holes 6 is 0.57% of the area of the first perforated plate 3.

[0043] In this embodiment, the aperture diameter of the first hole 6 is 3.5 mm.

[0044] In this embodiment, the area of the second hole 7 is 0.57% of the area of the second perforated plate 4.

[0045] In this embodiment, the aperture diameter of the second hole 7 is 3.5 mm.

[0046] In this embodiment, the first hole 6 is close to the lower end of the first perforated plate 3, and the second hole 7 is close to the upper end of the second perforated plate 4.

[0047] The curling cavity 2 has a rectangular structure. The distance from the first perforated plate 3 to the left end of the curling cavity 2 is equal to the distance from the first perforated plate 3 to the second perforated plate 4, which is equal to the distance from the second perforated plate 4 to the right end of the curling cavity 2.

[0048] The distance from the first hole 6 to the lower end of the curling cavity 2 is equal to the distance from the second hole 7 to the upper end of the curling cavity 2.

[0049] In this embodiment, the materials of the perforated front panel 1, the curling cavity 2, the first perforated plate 3, and the second perforated plate 4 are all photosensitive resins.

[0050] In addition, the present invention also provides an application of the ultra-thin low-frequency sound-absorbing metasurface unit structure, and installs the above ultra-thin low-frequency perfect sound-absorbing metasurface unit structure on the inner wall surface of the place that needs sound-absorbing treatment.

[0051] Embodiment 2

[0052] The following further describes the implementation manner of the present invention through Embodiment 2.

[0053] An ultra-thin low-frequency sound-absorbing metasurface unit structure includes a perforated front panel 1, a curling cavity 2, a first perforated plate 3, and a second perforated plate 4. The perforated front panel 1 uses a 0.2 cm thick printing material as a photosensitive resin. The size of the perforated front panel 1 is 10 cm long × 10 cm wide, and the perforation rate is 0.38%. The curling cavity 2 uses a 0.2 cm thick printing material as a photosensitive resin, and the thickness is 5.7 cm. The first perforated plate 3 and the second perforated plate 4 use a 0.2 cm thick printing material as a photosensitive resin. The sizes of the first perforated plate 3 and the second perforated plate 4 are 5.7 cm long × 3.06 cm wide, and the perforation rate is 0.57%. Each layer of the perforated inner plate has holes with an area accounting for 0.99% of the unit panel area, and the hole diameter is 3.5 mm.

[0054] The results are as Figure 3 and Figure 4As shown, the ultra-thin low-frequency perfect sound-absorbing metamaterial surface unit structure has excellent sound-absorbing performance when the thickness is 5.9 cm. The sound-absorbing coefficient of the first absorption peak is 0.99 at 95 Hz, the sound-absorbing coefficient of the second absorption peak is 0.99 at 270 Hz, and the sound-absorbing coefficient of the third absorption peak is 0.99 at 378 Hz.

[0055] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. An ultra-thin low-frequency sound-absorbing metamaterial surface unit structure, characterized in that, it includes a perforated front panel (1), a coiled cavity (2), a first perforated plate (3) and a second perforated plate (4). The perforated front panel (1) is provided at the front end of the coiled cavity (2). There are holes (5) on the perforated front panel (1). The first perforated plate (3) is located inside the coiled cavity (2). The upper and lower ends of the first perforated plate (3) are connected to the coiled cavity (2). The front end of the first perforated plate (3) is connected to the perforated front panel (1). There are first holes (6) on the first perforated plate (3). The second perforated plate (4) is located inside the coiled cavity (2). The upper and lower ends of the second perforated plate (4) are connected to the coiled cavity (2). The front end of the second perforated plate (4) is connected to the perforated front panel (1). There are second holes (7) on the second perforated plate (4).

2. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the area of the hole (5) is 0.38% of the area of the perforated front panel (1).

3. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the aperture of the hole (5) is 7 mm.

4. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the area of the first hole (6) is 0.57% of the area of the first perforated plate (3).

5. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the aperture of the first hole (6) is 3.5 mm.

6. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the area of the second hole (7) is 0.57% of the area of the second perforated plate (4).

7. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the aperture of the second hole (7) is 3.5 mm.

8. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the first hole (6) is close to the lower end of the first perforated plate (3), the second hole (7) is close to the upper end of the second perforated plate (4), the coiled cavity (2) is a rectangular structure. The distance from the first perforated plate (3) to the left end of the coiled cavity (2) is equal to the distance from the first perforated plate (3) to the second perforated plate (4) and is equal to the distance from the second perforated plate (4) to the right end of the coiled cavity (2); the distance from the first hole (6) to the lower end of the coiled cavity (2) is equal to the distance from the second hole (7) to the upper end of the coiled cavity (2).

9. The ultra-thin low-frequency sound-absorbing metamaterial surface unit structure according to claim 1, characterized in that, the materials of the perforated front panel (1), the coiled cavity (2), the first perforated plate (3) and the second perforated plate (4) are all photosensitive resins.

10. An application of an ultra-thin low-frequency sound-absorbing metamaterial surface unit structure, characterized in that, install the ultra-thin low-frequency perfect sound-absorbing metamaterial surface unit structure according to any one of claims 1-9 on the inner wall surface of the place that needs sound-absorbing treatment.

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