A thin-film low-frequency noise reduction structure based on a bionic spider web

Abstract

The present invention relates to the field of noise reduction structures, and specifically to a thin film low-frequency noise reduction structure based on a bionic spider web, comprising a pure polyimide (PI) film and a straight aluminum alloy vibrator, a cross aluminum alloy vibrator and a central cross vibrator attached to the pure polyimide (PI) film, an ethylene vinyl acetate copolymer (EVA) ring is evenly arranged on the outer circumference of the pure polyimide (PI) film, the central cross vibrator is located at the center of the pure polyimide (PI) film, and the straight aluminum alloy vibrator and the cross aluminum alloy vibrator are symmetrically arranged around the central cross vibrator. The noise reduction structure of the present invention not only has a high noise reduction efficiency, but also can achieve the requirements of lightweight and miniaturization of the structure.

Description

Technical Field

[0001] The invention relates to the field of noise reduction structures, and in particular to a thin film low-frequency noise reduction structure based on a bionic spider web. Background Art

[0002] At present, high-frequency noise reduction technology is relatively mature, but due to the long wavelength of low-frequency sound waves, its effective control is still a challenging problem. For low-frequency noise, conventional noise reduction methods mostly increase the size of the noise reduction structure or increase the mass to improve the sound wave blocking effect. However, this type of traditional low-frequency sound insulation barrier can hardly meet the needs of development. Therefore, pursuing a lightweight and thin noise reduction structure to achieve effective control of low-frequency noise is one of the key issues that need to be urgently solved in the field of sound insulation and noise reduction.

[0003] For low-frequency noise, conventional noise reduction methods mostly use increasing the size of the noise reduction structure or increasing the mass to improve the sound wave blocking effect. However, with the continuous improvement of the requirements for structural quality or volume in modern advanced engineering, this type of traditional low-frequency sound insulation barrier has been difficult to meet the needs of development. Therefore, pursuing a lightweight and thin noise reduction structure to achieve effective control of low-frequency noise is one of the key issues that need to be urgently solved in the field of sound insulation and noise reduction.

[0004] Acoustic metamaterials based on local resonance can achieve the bandgap effect of low-frequency sound waves through small-size structures, thereby effectively preventing the propagation of low-frequency sound waves, opening up a new path for the field of low-frequency noise reduction. As a type of local resonance metamaterial, thin-film acoustic metamaterials have particularly excellent sound reflection and absorption properties, and are thin and light, which coincides with the material properties pursued by low-frequency noise reduction. However, research on thin-film acoustic metamaterials still has the following limitations:

[0005] (1) The anti-resonance modes of traditional acoustic metamaterials are generated intermittently within a wide frequency range, which causes the discontinuity of the anti-resonance modes and is also the main reason why the bandwidth of sound transmission loss is usually narrow in the low-frequency region.

[0006] (2) Existing acoustic metamaterials have more or less weak links that restrict their application research, such as large and heavy structures, rigid frames, rapid aging of membrane materials (rubber), unstable membrane tension, additional heavy resonators, and complex structures. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a thin film low-frequency noise reduction structure based on a bionic spider web, which not only has a high noise reduction efficiency, but also can achieve the requirements of lightweight and miniaturization of the structure.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A thin-film low-frequency noise reduction structure based on a bionic spider web comprises a pure polyimide (PI) film and a straight aluminum alloy vibrator, a cross-shaped aluminum alloy vibrator and a central cross vibrator attached to the pure polyimide (PI) film. An ethylene vinyl acetate copolymer (EVA) ring is evenly arranged on the outer circumference of the pure polyimide (PI) film. The central cross vibrator is located at the center of the pure polyimide (PI) film. The straight aluminum alloy vibrator and the cross-shaped aluminum alloy vibrator are symmetrically arranged around the central cross vibrator.

[0010] Furthermore, the thickness of the pure polyimide (PI) film is 0.2 mm.

[0011] Furthermore, the length, width and height of the straight aluminum alloy vibrator are 14 mm, 2 mm and 1.8 mm respectively.

[0012] Furthermore, the ethylene vinyl acetate copolymer (EVA) ring has a thickness of 2 mm, an outer diameter of 100 mm, and a width of 5 mm.

[0013] Furthermore, the central cross vibrator is made of Elast-blk-10.

[0014] Furthermore, the number of the straight aluminum alloy vibrators is 2 groups, which are symmetrically arranged on both sides of the horizontal side and the vertical side of the central cross vibrator.

[0015] Furthermore, the number of the cross-shaped aluminum alloy vibrators is 2 groups, which are respectively arranged between two adjacent straight-line aluminum alloy vibrators and are symmetrical with the central cross as the center.

[0016] Furthermore, the straight aluminum alloy vibrator, the cross aluminum alloy vibrator, the central cross vibrator and the ethylene vinyl acetate copolymer (EVA) ring are all bonded to the pure polyimide (PI) film by glue.

[0017] The present invention has the following beneficial effects:

[0018] The noise reduction structure of the present invention not only has a high noise reduction efficiency, but also can achieve the requirements of lightweight and miniaturization of the structure.

[0019] The noise reduction structure of the present invention can generate continuous multi-level anti-resonance modes, thereby achieving the purpose of improving the bandwidth and amplitude of structural sound transmission loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a thin film low-frequency noise reduction structure based on a bionic spider web according to an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of the structure of a cross-shaped aluminum alloy vibrator in an embodiment of the present invention.

[0022] Figure 3 Schematic diagram of the structure of the central cross vibrator in an embodiment of the present invention.

[0023] Figure 4 Schematic diagram of the STL curve comparison between the spider web model and the comparison verification model.

[0024] In the figure: (a) frequency is 5-1600Hz; (b) frequency is 5-3000Hz. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0026] like Figure 1-Figure 3 As shown, an embodiment of the present invention provides a thin film low-frequency noise reduction structure based on a bionic spider web, comprising a pure polyimide (PI) film 1 with a thickness of 0.2 mm, and a straight aluminum alloy vibrator 2, a cross-shaped aluminum alloy vibrator 3 and a central cross vibrator 5 bonded to the pure polyimide (PI) film 1 by glue; an ethylene vinyl acetate copolymer (EVA) ring 4 is uniformly bonded on the outer circumference of the pure polyimide (PI) film by glue, and the central cross vibrator 5 is made of Elast-blk-10, with a length of 36 mm, a width of 4 mm, and a thickness of 2 mm, and is located at the pure polyimide (PI) film. The center position of the imide (PI) film 1; the length, width and height of the I-shaped aluminum alloy vibrator 2 are 14mm, 2mm and 1.8mm respectively, and there are 2 groups of them, which are symmetrically arranged on both sides of the horizontal side and the vertical side of the central cross vibrator; the vertical and horizontal lengths of the cross-shaped aluminum alloy vibrator 3 are 6mm, the width is 2mm, the thickness is 1.8mm, and there are 2 groups of them, which are respectively arranged between two adjacent I-shaped aluminum alloy vibrators, and are symmetrical with the central cross as the center; the thickness of the ethylene vinyl acetate copolymer (EVA) ring 5 is 2mm, the outer diameter is 100mm, and the width is 5mm.

[0027] The material parameters of the present invention are shown in Table 1.

[0028] Table 1 Structure and material parameters in the film model

[0029]

[0030] Experimental example

[0031] In this embodiment, the frame and the vibrator of EVA material are manufactured by 3D printing, the metal vibrator is manufactured by mechanical processing, the PI film is selected as a finished product, and finally all the parts are bonded and assembled, and then placed in an acoustic impedance tube for testing.

[0032] Test Method

[0033] This embodiment is based on the GB / T 27764-2011 standard "Transfer Matrix Method for Measurement of Sound Transmission Loss in Acoustic Impedance Tubes". The acoustic metamaterial model designed is tested using an acoustic impedance tube and the measured value of its sound transmission loss is given. The experiment uses a fixed-position four-microphone method to measure the acoustic metamaterial specimen, and the experimental sampling frequency is 0.78125Hz. The measurement frequency range is related to the distance between the microphones and the diameter of the impedance tube. The diameter of the acoustic impedance tube used in this article is 100mm, and the measurement frequency range is 80-1600Hz.

[0034] This embodiment uses structural weight and STL sound transmission loss (STL) to measure the sound insulation performance and efficiency of the structure. STL can refer to the energy loss when sound energy passes through the structure, as shown in Formula 1:

[0035]

[0036] Among them, P 0 is the incident sound pressure, the test amplitude is set to 1Pa, P τ is the transmitted sound pressure, the transmitted sound energy E τ and the incident sound energy E 0 The ratio of is the acoustic energy transmission coefficient τ. <> and || are the average value and modulus of the parameters respectively.

[0037] The model in the reference "Broadband low-frequency membrane-type acousticmetamaterials with multi-state anti-resonances" was selected as a comparison model for comparative testing. The test results are as follows Figure 4 As shown:

[0038] like Figure 4 As shown in (a), according to the STL curve of the spider web model, the first low-frequency STL bandwidth is between 50Hz and 1170Hz (STL bandwidth is 1120Hz), and the STL peak at 775Hz is 49.24dB; the second low-frequency STL bandwidth is between 1170Hz and 1825Hz (STL bandwidth is 655Hz), and the STL peak at 1290Hz is 35.49dB.

[0039] like Figure 4 As shown in (b), the frequency bands with STL values ​​greater than 10dB within 3000Hz are 5-15Hz, 145-1755Hz, 1870hz-1960Hz, and 2350hz-3000Hz. The total bandwidth with STL values ​​greater than 10dB is 2360Hz, of which the total bandwidth greater than 10dB within 1600Hz is 1465Hz.

[0040] In summary, compared with the reference model, the spider web model of the present invention has a STL peak with a wider bandwidth (1610Hz) in the range of 145Hz-1755Hz, and has good mid- and low-frequency noise reduction performance in this section. At the same time, this section corresponds to most low-frequency noise. In a wider total bandwidth of 3000Hz with an STL value greater than 10dB. Especially in the comparison of bandwidth greater than 10dB within 1600Hz, the maximum single-peak bandwidth of the spider web model is 61% wider than the maximum single-peak bandwidth of the verification model. Its total bandwidth greater than 10dB is 26% wider than that of the verification model, accounting for 91% of the 0-1600Hz sampling interval.

[0041] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A thin film low-frequency noise reduction structure based on a bionic spider web, characterized in that: It includes a pure polyimide film and a straight aluminum alloy vibrator, a cross aluminum alloy vibrator and a central cross vibrator attached to the pure polyimide film. An ethylene vinyl acetate copolymer ring is evenly arranged on the outer circumference of the pure polyimide film. The central cross vibrator is located at the center of the pure polyimide film. The straight aluminum alloy vibrator and the cross aluminum alloy vibrator are symmetrically arranged around the central cross vibrator. The number of the straight aluminum alloy vibrators is 2 groups, which are symmetrically arranged on both sides of the horizontal side and both sides of the vertical side of the central cross vibrator; the number of the cross aluminum alloy vibrators is 2 groups, which are respectively arranged between two adjacent straight aluminum alloy vibrators, and the symmetry is achieved with the central cross as the center.

2. The thin film low-frequency noise reduction structure based on a bionic spider web as claimed in claim 1, characterized in that: The thickness of the pure polyimide film is 0.2 mm.

3. The thin film low-frequency noise reduction structure based on a bionic spider web as claimed in claim 1, characterized in that: The length, width and height of the straight aluminum alloy vibrator are 14 mm, 2 mm and 1.8 mm respectively.

4. The thin film low-frequency noise reduction structure based on a bionic spider web as claimed in claim 1, characterized in that: The ethylene vinyl acetate copolymer ring has a thickness of 2 mm, an outer diameter of 100 mm, and a width of 5 mm.

5. The thin film low-frequency noise reduction structure based on a bionic spider web as claimed in claim 1, characterized in that: The central cross vibrator is made of Elast-blk-10.

6. The thin film low-frequency noise reduction structure based on a bionic spider web as claimed in claim 1, characterized in that: The straight aluminum alloy vibrator, the cross aluminum alloy vibrator, the central cross vibrator and the ethylene vinyl acetate copolymer ring are all bonded to the pure polyimide film by glue.

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