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CN-122024684-A - Broadband low-frequency sound absorption structure with sub-wavelength thickness

CN122024684ACN 122024684 ACN122024684 ACN 122024684ACN-122024684-A

Abstract

The invention discloses a broadband low-frequency sound absorption structure with sub-wavelength thickness, which relates to the technical field of noise control and comprises a box body and fractal components arranged in the box body in a rectangular array mode, wherein a first cavity is formed by combining four adjacent fractal components in the rectangular array mode, and a plurality of fractal components close to the inner side surface of the box body and the inner side surface of the box body are combined to form a second cavity; the fractal component comprises a first plate body and a second plate body, wherein the first plate body is provided with a third cavity, the second plate body is provided with a fourth cavity, the top surface of the box body is provided with a cover plate, and the cover plate is provided with a plurality of through holes which are respectively communicated with the first cavity, the second cavity, the third cavity and the fourth cavity. The broadband low-frequency sound absorption structure with the sub-wavelength thickness solves the technical problems that the existing composite sound absorption structure can only match the sound wave resonance requirement of a limited frequency band, the sound absorption frequency band range is narrower, and the design of lightening and thinning of the sub-wavelength magnitude can not be realized.

Inventors

  • LI JINGRU
  • CHEN SIYU
  • LIU YIFENG
  • ZHANG ZHIFU
  • SHANG KEXIN

Assignees

  • 海南大学

Dates

Publication Date
20260512
Application Date
20260302

Claims (10)

  1. 1. The broadband low-frequency sound absorption structure with the sub-wavelength thickness is characterized by comprising a box body (100) and fractal members (200) arranged in the box body (100) in a rectangular array mode, wherein two adjacent fractal members (200) are connected, a first cavity (240) is formed by combining four adjacent fractal members (200) which are arranged in a rectangular array mode, and a plurality of fractal members (200) close to the inner side surface of the box body (100) are combined with the inner side surface of the box body (100) to form a second cavity (250); The fractal member (200) comprises a first plate body (210) and a second plate body (220) arranged on the circumferential outer side of the first plate body (210), wherein the second plate body (220) is of an equal-ratio reduced structure of the first plate body (210), the first plate body (210) is provided with a third cavity (211), and the second plate body (220) is provided with a fourth cavity (221); The top surface of box body (100) is provided with and is used for sealing apron (110) of box body (100), the lateral surface of apron (110) is towards the sound source, just be provided with on apron (110) a plurality of respectively with first cavity (240), second cavity (250), third cavity (211) and through-hole (111) that fourth cavity (221) are linked together.
  2. 2. The broadband low-frequency sound absorbing structure of sub-wavelength thickness according to claim 1, wherein the first plate body (210) and the second plate body (220) are both star-shaped, and the first plate body (210) alternately arranges a plurality of first convex corners (212) and a plurality of first concave corners (213) along its own circumferential direction, the second plate body (220) is arranged at the first convex corners (212) and the first concave corners (213), respectively, and the second plate body (220) alternately arranges a plurality of second convex corners (222) and a plurality of second concave corners (223) along its own circumferential direction.
  3. 3. The broadband low-frequency sound absorbing structure of sub-wavelength thickness according to claim 2, wherein the through hole (111) on the cover plate (110) communicating with the third cavity (211) is located at the position of the second lobe (222) on the projection plane of the first direction, and the through hole (111) on the cover plate (110) communicating with the fourth cavity (221) is located at the position of the second lobe (222).
  4. 4. A broadband low frequency sound absorbing structure of sub-wavelength thickness according to any of claims 1-3, characterized in that the dimensional ratio between the second plate body (220) and the first plate body (210) is 1:6-1:2.
  5. 5. A broadband low frequency sound absorbing structure of sub-wavelength thickness according to any of claims 1-3, characterized in that the fractal member (200) comprises a thick-walled portion with a thickness dimension between 1-2mm and a thin-walled portion with a thickness dimension between 0.25-0.5 mm.
  6. 6. The broadband low-frequency sound absorbing structure of sub-wavelength thickness according to claim 5, characterized in that the thickness dimension of the cover plate (110) is between 0.5-1.5mm, and the diameter of the through hole (111) is between 0.8-1.5 mm.
  7. 7. A broadband low frequency sound absorbing structure of sub-wavelength thickness according to claim 2 or 3, characterized in that the fractal member (200) is entirely square in structure and the side length of the whole fractal member (200) is between 20-30 mm.
  8. 8. Broadband low-frequency sound absorbing structure of sub-wavelength thickness according to claim 7, characterized in that a connecting rod (230) for connecting two adjacent fractal members (200) is arranged at the position of the second concave angle (223), and the distance between the connecting rod (230) and the inner side surface of the box body (100) is between 1-5 mm.
  9. 9. A broadband low frequency sound absorbing structure according to claim 2 or 3, characterized in that the first plate (210) and the second plate (220) are equal in height, and the first plate (210) and the second plate (220) are each between 50-90mm in height, and the first lobe (212) and the second lobe (222) are included between 40-60 °.
  10. 10. The broadband low-frequency sound absorption structure according to claim 8, wherein the materials of the box body (100), the cover plate (110), the first plate body (210), the second plate body (220) and the connecting rod (230) are one of a composite material formed by combining metal, carbon fiber and glass fiber, resin and plastic.

Description

Broadband low-frequency sound absorption structure with sub-wavelength thickness Technical Field The invention relates to the technical field of noise control, in particular to a broadband low-frequency sound absorption structure with sub-wavelength thickness. Background Low-frequency noise is a core problem for treating noise in industrial and civil environments because of the characteristics of long transmission, strong penetration, slow energy attenuation and the like. The traditional porous sound absorption material relies on the internal pore to dissipate sound energy, the sound wave wavelength of 1/4 or more is required to be effectively absorbed in a low frequency band, the light and thin engineering requirements cannot be met, while resonance sound absorption structures such as a Helmholtz resonator, a single-layer perforated plate and the like can enhance low frequency sound absorption through resonance effect, but the sound absorption frequency band is narrow (only 10% -20% of the central frequency), and the whole broadband sound absorption range is difficult to cover. The cover plate sound absorption structure has the advantages of simple structure, strong weather resistance and the like through the vibration friction and resonance of the air column at the through hole, but the balance of high sound absorption coefficient and sub-wavelength thickness is difficult to realize in a low-frequency broadband simply by virtue of the design of the cover plate. The existing composite sound absorption structure improves sound absorption performance through coupling of multiple components, but adopts a conventional geometric configuration, has a single structural dimension, can only match with the sound wave resonance requirement of a limited frequency band, has a narrower sound absorption frequency band range, can enhance the low-frequency sound absorption effect only by increasing the depth or thickness of a cavity, is low-frequency sound absorption, and cannot realize the light and thin design of sub-wavelength magnitude due to the fact that the depth or the structural thickness of the cavity is often increased. Accordingly, a broadband low-frequency sound absorption structure for a sub-wavelength thickness solving the above-mentioned problems is proposed. Disclosure of Invention The invention aims to provide a broadband low-frequency sound absorption structure with sub-wavelength thickness, which solves the technical problems that the existing composite sound absorption structure can only match the sound wave resonance requirement of a limited frequency band, the sound absorption frequency band range is narrower, and the design of lightening and thinning of the sub-wavelength magnitude can not be realized. The invention provides a broadband low-frequency sound absorption structure with sub-wavelength thickness, which comprises a box body and fractal components arranged in the box body in a rectangular array mode, wherein two adjacent fractal components are connected, four adjacent fractal components are arranged in a rectangular array mode and are combined to form a first cavity, and a plurality of fractal components close to the inner side surface of the box body are combined with the inner side surface of the box body to form a second cavity; the fractal component comprises a first plate body and a second plate body arranged on the outer side of the periphery of the first plate body, wherein the second plate body is of an equal-ratio reduced structure of the first plate body, the first plate body is provided with a third cavity, and the second plate body is provided with a fourth cavity; The top surface of box body is provided with and is used for sealing the apron of box body, the lateral surface of apron is towards the sound source, just be provided with a plurality of respectively with first cavity the second cavity the third cavity and the through-hole that the fourth cavity is linked together on the apron. Preferably, the first plate body and the second plate body are both star-shaped, the first plate body is alternately provided with a plurality of first convex corners and a plurality of first concave corners along the circumferential direction of the first plate body, the first convex corner positions and the first concave corner positions are respectively provided with the second plate body, and the second plate body is alternately provided with a plurality of second convex corners and a plurality of second concave corners along the circumferential direction of the second plate body. Preferably, on a projection surface in the first direction, the through hole in the cover plate, which is communicated with the third cavity, is located at the second lobe position, and the through hole in the cover plate, which is communicated with the fourth cavity, is located at the second lobe position. Preferably, the dimension ratio between the second plate body and the first plate body is 1:6-1:2. Preferabl