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Half-perforated foam sound absorbing structure with variable connectivity rate

A technology with semi-open cells and high connectivity, which is applied in the direction of sound-generating devices and instruments, and can solve the problems of good high-frequency sound absorption performance and poor low-frequency sound absorption performance of semi-open-cell foam.

Inactive Publication Date: 2012-09-26
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Same as open-cell foam, semi-open-cell foam has good high-frequency sound absorption performance and poor low-frequency sound absorption performance

Method used

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  • Half-perforated foam sound absorbing structure with variable connectivity rate
  • Half-perforated foam sound absorbing structure with variable connectivity rate
  • Half-perforated foam sound absorbing structure with variable connectivity rate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Assume that there is a homogeneous semi-open cell foam with a thickness of 10mm along the sound incident direction, a connectivity rate of 0.25, a pore diameter of 1.24mm, and a porosity of 66.8%. Change the connectivity rate of the first 5mm to 0.2, and the connectivity rate of the rear 5mm to 0.3. The homogeneous semi-open-cell foam has the same mass and volume as the semi-open-cell foam with a sudden change in connectivity, but the sound absorption performance at low and medium frequencies has increased by 30% to 40%. image 3 Shown is the comparison of the sound absorption performance of the semi-open-cell foam with a sudden change in connectivity rate and the homogeneous semi-open-cell foam in this embodiment.

Embodiment 2

[0021] Assume that there is a homogeneous semi-open cell foam with a thickness of 10mm along the sound wave incident direction, a pore diameter of 1.24mm, a connectivity rate of 0.25, and a porosity of 66.8%. Vary the connectivity ratio linearly from 0.16 to 0.34 along the direction of acoustic wave incidence. The connectivity rate increases linearly. The semi-open-cell foam has the same mass and volume as the homogeneous semi-open-cell foam, but the mid-low frequency sound absorption performance is improved by 30% to 50%. For example, Figure 4 Shown is the comparison of the sound absorption properties of the semi-open-cell foam with linearly increasing connectivity rate and the homogeneous semi-open-cell foam in this embodiment.

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Abstract

The invention discloses a half-perforated foam sound absorbing structure with variable connectivity rate, wherein the connectivity rate is gradually increased along the acoustic wave incidence direction, and the variance is that the connectivity rate is abruptly increased along the acoustic wave incidence direction or linearly increased along the acoustic wave incidence direction; and when the acoustic wave is propagated from a communicating pore to a main pore, as the volume is abruptly expanded for 10 times to even dozens of times, the acoustic wave kinetic energy is attenuated due to the abrupt variance of the volume, the acoustic energy quickly works externally so as to be converted into heat energy for dissipation. Compared with the conventional isotropic structure, the connectivity rate variance structure has lower connectivity rate at the front end, so that the sound absorbing effect is increased; the higher connectivity rate at the rear end enables the resonant frequency of the structure to shift to low frequency, so as to improve the integral sound absorbing property of the half-perforated foam sound absorbing structure with variable connectivity rate. Compared with the isotropic half-perforated foam sound absorbing structure, the structure has the advantages that the low and medium frequency sound absorbing property is improved for 30% to 50%.

Description

technical field [0001] The invention relates to a semi-open-cell foam sound-absorbing structure, in particular to a semi-open-cell foam sound-absorbing structure with variable connectivity. Background technique [0002] With the development of society, the noise problem is becoming more and more serious. Noise directly affects the quality of life of human beings, and even has an impact that cannot be underestimated on human psychology, physiology and many other aspects. Therefore, noise is a serious pollution that must be controlled. At present, it has become a very economical, reasonable and effective means to control noise through the principle of sound absorption in construction and various engineering fields. [0003] Sound absorption refers to the phenomenon that the sound energy is converted into heat energy and dissipated when the sound is incident on a certain interface and passes through the medium. The sound absorption capacity of a material is characterized by t...

Claims

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Application Information

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IPC IPC(8): G10K11/165
Inventor 孟晗辛锋先卢天健
Owner XI AN JIAOTONG UNIV
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