Silencing unit, silencing unit construction method and silencing structure

Abstract

The invention belongs to the technical field of silencing and noise reduction, and discloses a silencing unit, a silencing unit construction method and a silencing structure. Each silencing unit comprises an acoustic impedance coupling structure and a plurality of resonant cavity structures which are connected in parallel and sequentially arranged in the X direction and / or the Y direction, the interiors of the resonant cavity structures are hollow to form inner cavities, different resonant cavity structures are provided with through hole panels with different porosities in the Z direction, and sound waves can enter the inner cavities through silencing holes formed in the through hole panels. An acoustic impedance coupling channel is formed in the acoustic impedance coupling structure, the acoustic impedance coupling structure is arranged in the resonant cavity structure, and inner cavities of the two resonant cavity structures located at the two ends are connected in a penetrating mode in the X direction; and at least one resonant cavity structure between the resonant cavity structures at the two ends is not communicated with the acoustic impedance coupling channel. Based on an existing manufacturing process, the silencing unit can effectively regulate and control the height in the axis direction, the low-frequency noise reduction effect is enhanced, and the range of the silencing frequency band is widened.

Description

Technical Field

[0001] This invention relates to the field of noise reduction technology, and in particular to a noise reduction unit, a method for constructing the noise reduction unit, and a noise reduction structure. Background Technology

[0002] In everyday environments, simply laying porous sound-absorbing materials is the most direct and effective way to optimize noise reduction, with these materials being particularly effective at higher sound frequencies. However, in the field of aviation noise reduction, especially in typical applications such as aircraft power systems (engines / exhaust pipes), cabin interiors, and automated assembly (robotic drilling / riveting), porous sound-absorbing materials need to reach a thickness on the same order of magnitude as the wavelength to achieve effective acoustic impedance matching and sound energy dissipation. This significantly limits the engineering application of porous sound-absorbing materials in compact spaces. In contrast, the Helmholtz cavity structure, with its unique frequency-selective noise reduction characteristics, can achieve efficient sound energy dissipation at the resonant frequency in the low-frequency range.

[0003] While a parallel arrangement of multiple Helmholtz cavities with the same cavity depth, based on the Helmholtz resonance principle, can achieve a limited widening of the bandwidth at the resonant frequency, its inherent frequency domain limitations make it difficult to meet the ultra-wideband noise reduction requirements for low-frequency noise control in aviation. Therefore, it is necessary to use multiple Helmholtz cavities with different silencing characteristics at their resonant frequencies in parallel configuration to achieve ultra-wideband silencing through multi-band superposition. From an acoustic design and manufacturing perspective, to ensure sufficient noise waves enter the Helmholtz cavity and are dissipated, the cross-sectional area of ​​the silencing holes on the Helmholtz cavity should not be too small, and the thickness of the through-hole panel containing the silencing holes should not be too thick. Therefore, existing technologies generally increase the height of the Helmholtz cavity to increase its volume and adjust the resonant frequency to achieve efficient silencing at multiple low-frequency resonant frequencies.

[0004] However, while parallel Helmholtz cavities with different cavity depths can effectively enhance and broaden the noise reduction effect at different resonant frequencies, the different depths of these designs lead to an increase in the thickness of the entire structure at local locations, thus limiting its application in the compact space of aviation.

[0005] Therefore, there is an urgent need for a sound-absorbing unit, a method for constructing a sound-absorbing unit, and a sound-absorbing structure to solve the above problems. Summary of the Invention

[0006] According to one aspect of the present invention, the object is to provide a noise reduction unit that, based on existing manufacturing processes, can effectively adjust its height in the axial direction and can enhance low-frequency noise reduction and broaden the noise reduction frequency band.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] The noise reduction unit includes:

[0009] Multiple resonant cavity structures are connected in parallel and arranged sequentially along the X and / or Y directions. The resonant cavity structures are hollow to form an inner cavity. Different resonant cavity structures have through-hole panels with different porosities in the Z direction. Sound waves can enter the inner cavity through the sound-absorbing holes opened on the through-hole panels. The X, Y and Z directions are perpendicular to each other.

[0010] An acoustic impedance coupling structure is provided, wherein an acoustic impedance coupling channel is formed inside the acoustic impedance coupling structure, and the acoustic impedance coupling structure is disposed inside the resonant cavity structure and connects the inner cavities of the two resonant cavity structures located at both ends along the X direction; at least one resonant cavity structure located between the two resonant cavity structures is not connected to the acoustic impedance coupling channel.

[0011] As a preferred embodiment of the noise reduction unit provided by the present invention, the resonant cavity structure further includes a main body, the through-hole panel is disposed at one end of the main body in the Z direction, and the inner cavity is formed between the through-hole panel and the main body.

[0012] As a preferred embodiment of the noise reduction unit provided by the present invention, the noise reduction holes on the through-hole panel are multiple.

[0013] As a preferred embodiment of the noise reduction unit provided by the present invention, the acoustic impedance coupling structure is disposed at the bottom of the inner cavity away from the through-hole panel.

[0014] As a preferred embodiment of the noise reduction unit provided by the present invention, the plurality of acoustic impedance coupling structures in the noise reduction unit are arranged in parallel with each other; and / or,

[0015] The height dimensions of the various acoustic impedance coupling structures differ in the Z direction.

[0016] According to another aspect of the present invention, the object is to provide a method for constructing a noise-absorbing unit, the method being capable of constructing a noise-absorbing unit as described in any of the above embodiments, the method comprising:

[0017] S10. Based on the required noise reduction frequency band, and combining the noise reduction function between the Helmholtz cavity resonant frequency and the structural parameters of the noise reduction unit's structural geometric model, construct the geometric model of the resonant cavity structure and the through-hole panel.

[0018] S20. Combine multiple resonant cavity structures and through-hole panels in the silencing unit. Different resonant cavity structures or through-hole panels correspond to different silencing frequency bands. Design the number of silencing holes, the cross-sectional area of ​​the silencing holes and the height of the inner cavity in the through-hole panels on different resonant cavity structures to control the silencing frequency band of the silencing unit.

[0019] S30. Obtain the actual spatial height dimension of the installation of the silencing unit, add the geometric model of the acoustic impedance coupling structure to the geometric model in the resonant cavity structure, and unify the height of multiple resonant cavity structures to the actual spatial height dimension; and iteratively optimize the length and volume of the acoustic impedance coupling structure to generate a silencing frequency band other than the silencing frequency band that conforms to the silencing function.

[0020] S40. Utilize simulation optimization iteration and experimental verification to optimize the structural parameters of the geometric model of the noise reduction unit according to the required noise reduction frequency band, thereby widening the upper and lower limits of the noise reduction frequency band range.

[0021] As a preferred embodiment of the sound-absorbing unit construction method provided by the present invention, the structural parameters of the structural geometric model of the sound-absorbing unit include the number of sound-absorbing holes, the aperture of the sound-absorbing holes, the volume of the inner cavity of the resonant cavity structure, the height of the inner cavity of the resonant cavity structure, the length dimension of the acoustic impedance coupling structure in the X direction, and the volume of the acoustic impedance coupling structure.

[0022] According to another aspect of the present invention, the object is to provide a noise reduction structure comprising a plurality of noise reduction units as described in any of the above embodiments, wherein the plurality of noise reduction units are arranged sequentially in the X direction and / or Y direction.

[0023] As a preferred embodiment of the noise reduction structure provided by the present invention, the noise reduction unit can be installed in the inner and outer cabins of an aircraft and / or in an aircraft manufacturing plant.

[0024] As a preferred embodiment of the sound-absorbing structure provided by the present invention, the resonant cavity structure and the acoustic impedance coupling structure are fabricated using additive manufacturing; or...

[0025] The main body of the resonant cavity structure and the acoustic impedance coupling structure are respectively prepared by bending composite materials or by bending sheet materials; the through-hole panel is prepared by a hole-making process; the main body of the resonant cavity structure, the acoustic impedance coupling structure and the through-hole panel are bonded together.

[0026] The beneficial effects of this invention are:

[0027] The silencing unit provided by this invention includes an acoustic impedance coupling structure and multiple resonant cavity structures connected in parallel and arranged sequentially along the X and / or Y directions. Each resonant cavity structure has a hollow interior cavity. Different resonant cavity structures have through-hole panels with different porosities in the Z direction. Sound waves can enter the hollow interior cavity of the resonant cavity structure through the silencing holes in the through-hole panels. The air inside the interior cavity is periodically compressed or expanded under the action of sound pressure, thereby dissipating the sound wave energy.

[0028] The acoustic impedance coupling structure has an internal acoustic impedance coupling channel, which is located inside the resonant cavity structure and connects the inner cavities of the two resonant cavity structures located at both ends along the X-direction. At least one resonant cavity structure located between the two ends is not connected to the acoustic impedance coupling channel. Through the above configuration, a dual-cavity acoustic coupling system can be formed, which can effectively adjust the height in the axial direction. This generates a new noise reduction frequency band based on the original structure's use of the Helmholtz cavity principle and micro-perforated plate theory for noise reduction, achieving low-frequency noise reduction and further widening the noise reduction frequency band range. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the silencing unit with the same cavity depth configuration provided in Embodiment 1 of the present invention;

[0030] Figure 2 This is a top view of the through-hole panel of the silencing unit with the same cavity depth configuration provided in Embodiment 1 of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of the silencing unit with different cavity depth configurations provided in Embodiment 2 of the present invention;

[0032] Figure 4 This is a top view of the through-hole panel of the silencing unit with different cavity depth configurations provided in Embodiment 2 of the present invention.

[0033] In the picture:

[0034] 100. Resonance cavity structure; 110. Inner cavity; 120. Silencing hole; 130. Main body; 140. Through-hole panel;

[0035] 200. Acoustic impedance coupling structure. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connect," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] In this embodiment, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this invention, the character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0044] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0045] Example 1

[0046] Figure 1 This diagram shows a structural schematic of a sound-absorbing unit with the same cavity depth provided in Embodiment 1 of the present invention; Figure 2 This image shows a top view of the through-hole panel of the silencing unit with the same cavity depth configuration provided in Embodiment 1 of the present invention. (Refer to...) Figure 1 and Figure 2 This embodiment employs a noise reduction unit. The noise reduction unit includes an acoustic impedance coupling structure 200 and multiple resonant cavity structures 100 arranged in parallel along the X and / or Y directions. Each resonant cavity structure 100 has a hollow interior forming an inner cavity 110. Different resonant cavity structures 100 have through-hole panels 140 with different porosities in the Z direction, allowing sound waves to enter the inner cavity 110 through noise reduction holes 120 formed on the through-hole panels 140. In this embodiment, the X, Y, and Z directions are perpendicular to each other. Based on the Helmholtz cavity resonance principle and the micro-perforated plate theory, the reversible compression and expansion process of the air within the inner cavity 110 under sound pressure promotes sound wave energy consumption, thereby achieving noise reduction.

[0047] Specifically, an acoustic impedance coupling channel is formed inside the acoustic impedance coupling structure 200. The acoustic impedance coupling structure 200 is disposed inside the resonant cavity structure 100, and connects the inner cavities 110 of the two resonant cavity structures 100 located at both ends along the X-direction. At least one resonant cavity structure 100 located between the two ends is not connected to the acoustic impedance coupling channel. The aforementioned acoustic impedance coupling structure 200 serves as a waveguide structure. By designing the geometry (length and volume) of the acoustic impedance coupling structure 200, the acoustic energy transfer path is directionally controlled. Combined with the acoustic wave coupling resonance effect in the resonant cavity structures 100 located at both ends, this improves the attenuation of acoustic energy during transmission or the transmission loss in a specific frequency band.

[0048] Through the above design, a dual-cavity acoustic coupling system can be formed, which can generate a new noise reduction frequency band on the basis of the original structure using the Helmholtz cavity principle and the micro-perforated plate theory to reduce noise, thereby achieving the effect of widening the noise reduction frequency band.

[0049] In other words, compared with the prior art, the noise reduction unit provided in this embodiment can effectively control the size of the resonant cavity structure 100 in the Z direction under the existing manufacturing process, thereby achieving low-frequency noise reduction effect and further widening the bandwidth of the noise reduction frequency band.

[0050] Optionally, the through-hole panel 140 may have multiple sound-absorbing holes 120. By designing the physical parameters such as the number, cross-sectional area, and arrangement of the sound-absorbing holes 120, the resonant coupling effect of the sound-absorbing unit at different frequencies can be effectively controlled.

[0051] More specifically, the acoustic impedance coupling structure 200 is disposed at the bottom of the inner cavity 110 away from the through-hole panel 140.

[0052] In this embodiment, a noise reduction unit comprising twenty resonant cavity structures 100 is described as an example. Four resonant cavity structures 100 under the same Y coordinate are arranged sequentially along the X direction, and the twenty resonant cavity structures 100 are divided into five groups, with the five groups of resonant cavity structures 100 arranged sequentially along the Y direction.

[0053] Specifically, refer to Figure 1 In this embodiment, five acoustic impedance coupling structures 200 are provided in the twenty resonant cavity structures 100. Each acoustic impedance coupling structure 200 is arranged along the X direction and passes through a corresponding set of resonant cavity structures 100.

[0054] More specifically, the acoustic impedance coupling structure 200 is disposed inside the end of the resonant cavity structure 100 away from the silencing hole 120 in the Z direction, and the acoustic impedance coupling structure 200 is hollow inside. In this embodiment, the cross-section of the acoustic impedance coupling structure 200 is rectangular. In other embodiments, the cross-section of the acoustic impedance coupling structure 200 can also be semi-circular or other shapes, as long as it can form a protrusion at the bottom of the inner cavity 110 away from the silencing hole 120 and connect the inner cavities 110 of the two resonant cavity structures 100.

[0055] More specifically, in the silencing unit provided in this embodiment, multiple acoustic impedance coupling structures 200 are arranged parallel to each other and spaced apart in the Y direction. The height dimensions of different acoustic impedance coupling structures 200 in the Z direction can be different. This arrangement facilitates the design and iterative optimization of the silencing unit and reduces manufacturing difficulty.

[0056] More specifically, there are multiple silencing holes 120, and these multiple silencing holes 120 are evenly arrayed at one end of the resonant cavity structure 100. The diameter and number of silencing holes 120 on each resonant cavity structure 100 can be different. Different diameters and numbers of silencing holes 120, along with different lengths of acoustic impedance coupling structures 200, can achieve noise reduction in different frequency bands.

[0057] Continue to refer to Figure 1 and Figure 2 The resonant cavity structure 100 also includes a body 130. The inner cavity 110 is formed between the through-hole panel 140 and the body 130. The cross-sectional area of ​​the body 130 is a regular hexagonal structure.

[0058] Continue to refer to Figure 1 and Figure 2 This embodiment also provides a noise reduction structure. The noise reduction structure includes multiple noise reduction units, which are arranged sequentially in the X and / or Y directions.

[0059] The aforementioned noise reduction structure can be installed in the aircraft's interior and exterior cabins and / or aircraft manufacturing plants and / or other areas requiring noise reduction. In this embodiment, the areas requiring noise reduction can specifically be the aircraft's power system (engine / exhaust pipes), the cabin interior, and automated assembly areas (robotic drilling / riveting), etc.

[0060] Example 2

[0061] This embodiment also provides a method for constructing a noise-absorbing unit. This method can be used to construct the noise-absorbing unit provided in Embodiment 1, and includes:

[0062] Step S10: Based on the required noise reduction frequency band, and combining the noise reduction function between the Helmholtz cavity resonant frequency and the structural parameters of the noise reduction unit's structural geometric model, construct the geometric model of the resonant cavity structure 100 and the through-hole panel 140.

[0063] Specifically, the basic noise reduction function is as follows:

[0064] ,

[0065] in,

[0066] f is the resonant frequency; S is the cross-sectional area of ​​the silencing hole 120; V is the volume of the inner cavity 110; L is the thickness of the through-hole panel 140; d is the cross-sectional diameter of the silencing hole 120; σ is the end correction factor, usually taken as 0.8.

[0067] It should be noted that in step S10, the approximate values ​​of the structural parameters of the geometric model of the resonant cavity structure 100 and the through-hole panel 140 in the noise reduction unit can be calculated according to the above formula. The specific accurate values ​​can be obtained through subsequent simulation iterations.

[0068] Step S20: Combine multiple resonant cavity structures 100 and through-hole panels 140 in the silencing unit. Different resonant cavity structures 100 or through-hole panels 140 correspond to different silencing frequency bands. Design the number of silencing holes 120, the cross-sectional area of ​​the silencing holes 120 and the height of the inner cavity 110 in the through-hole panels 140 on different resonant cavity structures 100, thereby controlling the silencing frequency band of the silencing unit.

[0069] Specifically, Figure 3 This diagram shows a silencing unit with different cavity depth configurations provided in Embodiment 2 of the present invention. Figure 4 This diagram shows a top view of the through-hole panel of a noise-reducing unit with different cavity depth configurations provided in Embodiment 2 of the present invention. Figure 3 and Figure 4 The diagram shown is a schematic of the combination of multiple resonant cavity structures 100 and through-hole panels 140 in the noise reduction unit according to the required noise reduction frequency band.

[0070] Step S30: Obtain the actual spatial height dimension of the installation of the silencing unit, add the geometric model of the acoustic impedance coupling structure 200 to the geometric model in the resonant cavity structure 100, and unify the height of multiple resonant cavity structures 100 to the actual spatial height dimension; and iteratively optimize the length and volume of the acoustic impedance coupling structure 200 to generate a silencing frequency band other than the silencing frequency that conforms to the silencing function.

[0071] Specifically, the structural parameters of the above-mentioned silencing unit's structural geometric model include the number of silencing holes 120, the diameter of the silencing holes 120, the volume of the inner cavity 110, the height of the inner cavity 110, the length of the acoustic impedance coupling structure 200 in the X direction, and the volume of the acoustic impedance coupling structure 200, etc.

[0072] Step S40: Utilizing simulation optimization iteration and experimental verification, based on the required noise reduction frequency band, the structural parameters of the geometric model of the noise reduction unit are optimized to broaden the upper and lower limits of the noise reduction frequency band. In this embodiment, through the above design and iterative optimization, an effect with a sound attenuation coefficient greater than 0.8 in the frequency range of 400-1800Hz can be achieved.

[0073] It should be noted that, in this embodiment, the resonant cavity structure 100 and the acoustic impedance coupling structure 200 are fabricated using additive manufacturing.

[0074] Alternatively, in other embodiments, the main body 130 of the resonant cavity structure 100 and the acoustic impedance coupling structure 200 are respectively prepared by composite bending or sheet metal bending; the through-hole panel 140 is prepared by hole making process; the main body 130 of the resonant cavity structure 100, the acoustic impedance coupling structure 200 and the through-hole panel 140 are bonded together.

[0075] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-disclosed concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

[0076] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A noise reduction unit, characterized in that, include: Multiple resonant cavity structures (100) are connected in parallel and arranged sequentially along the X and / or Y directions. The resonant cavity structure (100) is hollow to form an inner cavity (110). Different resonant cavity structures (100) are provided with through-hole panels (140) with different porosities in the Z direction. Sound waves can enter the inner cavity (110) through the sound-absorbing holes (120) opened on the through-hole panels (140). The X, Y and Z directions are perpendicular to each other. An acoustic impedance coupling structure (200) is provided, wherein an acoustic impedance coupling channel is provided inside the acoustic impedance coupling structure (200), and the acoustic impedance coupling structure (200) is provided inside the resonant cavity structure (100), and is connected in the X direction to the inner cavity (110) of the two resonant cavity structures (100) located at both ends; at least one of the resonant cavity structures (100) located between the two resonant cavity structures (100) is not connected to the acoustic impedance coupling channel.

2. The noise reduction unit according to claim 1, characterized in that, The resonant cavity structure (100) further includes a main body (130), the through-hole panel (140) is disposed at one end of the main body (130) in the Z direction, and the inner cavity (110) is formed between the through-hole panel (140) and the main body (130).

3. The noise reduction unit according to claim 1, characterized in that, The through-hole panel (140) has multiple sound-absorbing holes (120).

4. The noise reduction unit according to claim 1, characterized in that, The acoustic impedance coupling structure (200) is located at the bottom of the inner cavity (110) away from the through-hole panel (140).

5. The noise reduction unit according to claim 1, characterized in that, The plurality of acoustic impedance coupling structures (200) in the silencing unit are arranged in parallel to each other; and / or, The height dimensions of the plurality of acoustic impedance coupling structures (200) are different in the Z direction.

6. A method for constructing a noise-absorbing unit, characterized in that, The method for constructing a noise-absorbing unit can be used to construct a noise-absorbing unit as described in any one of claims 1-5, and the method for constructing a noise-absorbing unit includes: S10. Based on the required noise reduction frequency band, and combining the noise reduction function between the Helmholtz cavity resonant frequency and the structural parameters of the structural geometric model of the noise reduction unit, construct the geometric model of the resonant cavity structure (100) and the through-hole panel (140). S20. The multiple resonant cavity structures (100) and through-hole panels (140) in the silencing unit are combined. Different resonant cavity structures (100) or through-hole panels (140) correspond to different silencing frequency bands. The number of silencing holes (120), the cross-sectional area of ​​the silencing holes (120) and the height of the inner cavity (110) in the through-hole panels (140) on different resonant cavity structures (100) are designed to adjust the silencing frequency band of the silencing unit. S30. Obtain the actual spatial height dimension of the installation of the silencing unit, add the geometric model of the acoustic impedance coupling structure (200) to the geometric model of the resonant cavity structure (100), and unify the height of multiple resonant cavity structures (100) to the actual spatial height dimension; and iteratively optimize the length and volume of the acoustic impedance coupling structure (200) to generate a silencing frequency band other than the silencing frequency band that conforms to the silencing function; S40. Utilize simulation optimization iteration and experimental verification to optimize the structural parameters of the geometric model of the noise reduction unit according to the required noise reduction frequency band, thereby widening the upper and lower limits of the noise reduction frequency band range.

7. The method for constructing a noise reduction unit according to claim 6, characterized in that, The structural parameters of the geometric model of the silencing unit include the number of silencing holes (120), the aperture of the silencing holes (120), the volume of the inner cavity (110) of the resonant cavity structure (100), the height of the inner cavity (110) of the resonant cavity structure (100), the length of the acoustic impedance coupling structure (200) in the X direction, and the volume of the acoustic impedance coupling structure (200).

8. A sound-absorbing structure, characterized in that, It includes a plurality of noise reduction units as described in any one of claims 1-5, wherein the plurality of noise reduction units are arranged sequentially in the X direction and / or Y direction.

9. The sound-absorbing structure according to claim 8, characterized in that, The sound-absorbing structure can be installed in the aircraft's inner and outer cabins and / or aircraft manufacturing plant.

10. The sound-absorbing structure according to claim 8, characterized in that, The resonant cavity structure (100) and the acoustic impedance coupling structure (200) are fabricated using additive manufacturing; or, The main body (130) of the resonant cavity structure (100) and the acoustic impedance coupling structure (200) are respectively prepared by composite bending or plate bending; the through-hole panel (140) is prepared by hole making process; the main body (130), the acoustic impedance coupling structure (200) and the through-hole panel (140) are bonded together.

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