Composite sound-absorbing device with built in resonant cavity

a sound-absorbing device and cavity technology, applied in the field of composite sound-absorbing devices with built-in resonant cavities, can solve the problems of not being wide enough, unable to meet some practical needs of noise control engineering, and being almost impossible to realize in practice, so as to increase the acoustic impedance of the perforated board, and consume enough acoustic energy

Inactive Publication Date: 2012-10-04
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is a composite sound-absorbing device with built-in resonant cavity that increases sound absorption, enhances sound quality, and expands sound-absorbing frequency band. The resonant cavity is connected with the closed cavity via second pores to realize coupling resonance among cavities and so expand sound-absorbing frequency band. The resonant cavity and second pores can be different in size and shape to tune the resonant frequency and alter sound absorption coefficient under different frequencies. The invention makes full use of the principles of acoustic scattering, pores' acoustic impedance consuming acoustic energy, and sound absorption by multi-cavity coupled resonance, thus increasing sound absorption coefficient, enhancing the absorption of low and medium frequency noise, and expanding sound-absorbing frequency band.

Problems solved by technology

The technical problem addressed in this patent is the lack of effective sound-absorbing devices capable of efficiently absorbing low-frequency sounds in narrow spaces. Existing methods such as porous sound-absorbing materials and resonant sound-absorbing structures struggle to achieve optimal results due to limitations related to depth of cavity and tunability of resonance frequencies.

Method used

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  • Composite sound-absorbing device with built in resonant cavity
  • Composite sound-absorbing device with built in resonant cavity
  • Composite sound-absorbing device with built in resonant cavity

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Experimental program
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embodiment one

[0036]Referring to FIG. 1, the embodiment provides a composite sound-absorbing device with built-in resonant cavity. The device comprises a closed cavity formed by a perforated board 1, a back board 2 and side boards 3 all made up of stainless steel, wherein the depth D of the closed cavity is 40 mm. The perforated board 1 is a square board with the length of the side being 80 mm and the thickness being 5 mm. On the perforated board 1, first pores 6, with a diameter of 3 mm, are formed. The perforation rate σ of the first pores 6 is 28%. The first pores 6 are regularly arranged in the pattern of a square on the perforated board 1. In the closed cavity, four resonant cavities 5 are formed, with each resonant cavity 5 being made of aluminum and having a shape of sphere. The volume of the resonant cavity 5 is 1.4×104 mm3 and the thickness of the wall of the resonant cavity 5 is 5 mm. Moreover, on the wall of the resonant cavity 5, a second pore 6′, with a diameter of 2 mm, is formed. T...

embodiment two

[0037]Referring to FIG. 2, the present embodiment provides a composite sound-absorbing device with built-in resonant cavity according to the present invention. The device comprises a closed cavity formed by a perforated board 1, a back board 2 and side boards 3 all made of stainless steel, wherein the depth D of the closed cavity is 50 mm. The perforated board 1 is a round board, with a diameter of 100 mm and a thickness of 0.7 mm. On the perforated board 1, first pores 6, with a diameter of 1.7 mm, are formed. The perforation rate σ of the first pores 6 is 4.6%. The first pores 6 are arranged regularly in the pattern of a square on the perforated board 1. In the closed cavity, four resonant cavities are formed, with each resonant cavity being made of plastic. The volume of the resonant cavity 5 is 3.35×104 mm3 and the thickness of the wall of the resonant cavity 5 is 0.4 mm. Furthermore, there are 26 second pores 6′ on the wall of the resonant cavity 5, evenly distributed on the ci...

embodiment three

[0042]Referring to FIG. 2, the embodiment provides a composite sound-absorbing device with built-in resonant cavity. The device comprises a closed cavity formed by a perforated board 1, a back board 2 and side boards 3 all made up of stainless steel, with the depth D of the closed cavity being 100 mm. The perforated board 1 is a round board, with a diameter of 100 mm and thickness of 0.7 mm. On the perforated board 1, first pores 6, with a diameter of 1.7 mm are formed. The perforation rate of the first pores 6 is 4.6%. The first pores 6 are arranged regularly in a pattern of square on the perforated board 1. Separately, nine, seven, four and one resonant cavity 5, made of plastic and having a shape of sphere and a volume V of 3.35×104 mm3 and the thickness of the wall of the resonant cavity 5 being 0.4 mm, is arranged in the closed cavity. Furthermore, there are 26 second pores 6′ on the wall of the resonant cavity 5, evenly distributed on the circumferences of three mutually perpe...

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Abstract

The composite sound-absorbing device of the present invention includes a perforated board having a number of first pores thereon, a back board and side boards, the perforated board, back board and side boards forming a closed cavity, wherein: at least one or more of the resonant cavities being located within the closed cavity; at least one or more of second pores being located on the resonant cavities; at least one of the second pores being connected with the closed cavity; the resonant cavity having a volume of V=10 mm3 −1×1010 mm3, having a thickness of 0.05 mm-10 mm, the second pores having an aperture of d′=0.05-100 mm, with a perforation rate σ′=0.01%-30%. The present invention is beneficial to improve the effect of sound-absorbing and expand the frequency band of sound-absorbing.

Description

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Claims

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Application Information

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Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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