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Functionally graded materials and homogeneous dielectric periodic structure materials with continuously changing impedance

A technology of functionally graded materials and periodic structures, which can be used in sound-producing instruments, instruments, etc., can solve the problems of reducing the width of the band gap and reducing the initial frequency of the band gap, and achieves the effect of simple manufacturing process and strong designability.

Active Publication Date: 2018-08-31
HARBIN ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The structure is that two functionally graded materials are periodically arranged into a phononic crystal, and the functionally graded material satisfies a symmetrical distribution within a period. This structure effectively avoids problems such as fatigue and stress concentration in the phononic crystal. The bandgap starting frequency of the traditional structure is reduced, but the range of the bandgap starting frequency is limited, and the bandgap width is also reduced accordingly, and more passbands appear in the same range

Method used

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  • Functionally graded materials and homogeneous dielectric periodic structure materials with continuously changing impedance
  • Functionally graded materials and homogeneous dielectric periodic structure materials with continuously changing impedance
  • Functionally graded materials and homogeneous dielectric periodic structure materials with continuously changing impedance

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Embodiment 1

[0022] In this embodiment, the homogeneous medium is selected as copper, and the functionally graded material with continuously changing impedance and copper are both cylindrical, and the impedance of copper is 46.25×10 6 kg / [s m 2 ], the impedance distribution of functionally graded materials with continuously changing impedance is as figure 2 shown. image 3 It is the bandgap comparison result of the traditional periodic structure composed of rubber and copper and the functionally graded material with continuously changing impedance and the periodic structure composed of copper. It can be seen that the bandgap starting frequency of the traditional periodic structure is 7.5kHz, the cutoff frequency is 35kHz, and the bandgap width is 27.5kHz, while the bandgap starting frequency of the periodic structure composed of functionally graded materials with continuously changing impedance and copper is The initial frequency is 1kHz, the cut-off frequency is 38kHz, and the bandgap ...

Embodiment 2

[0024] In this embodiment, the homogeneous medium is selected as copper, the functionally graded material with continuously changing impedance and copper are both cylindrical, and the impedance value of the functionally graded material with continuously changing impedance is changed so that its impedance distribution satisfies a linearly increasing distribution, as Figure 4 shown. Figure 5 It is the bandgap comparison result of the traditional periodic structure composed of rubber and copper and the functionally graded material with continuously changing impedance and the periodic structure composed of copper. It can be seen that the bandgap starting frequency of the traditional periodic structure increases to 8.5kHz, the cutoff frequency increases to 45kHz, and the bandgap width is 36.5kHz, while the functionally graded material with continuously changing impedance and the periodic structure composed of copper The starting frequency of the bandgap is 0.5kHz, the cutoff freq...

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Abstract

The invention provides a continuously-variable-impedance functionally graded material and homogenous medium periodic structure material which is a periodic structure formed by continuously-variable-impedance functionally graded material and a homogenous medium according to periodic arrangement. A low-frequency band gap can be acquired via a relatively small periodic size so that the manufacturing technology is simple, designability is high, material selection range is relatively wide and thus the periodic structure material is suitable for being applied to the aspect of low-frequency vibration damping and noise reduction.

Description

technical field [0001] The invention relates to a periodic structure, in particular to a vibration-damping and sound-insulating periodic structure material in the field of vibration-damping and noise-reducing technology. Background technique [0002] In various fields such as mechanical power, aerospace, and ship engineering, periodic structures are often encountered as an acoustic structure. A periodic structure is composed of two or more elastic materials according to a certain periodicity. One of its important features is that it has an acoustic band gap, which can prevent certain frequencies of elastic waves from passing through. That is, the propagation of vibration in this frequency range is suppressed. However, the bandgap frequency of the periodic structure based on the Bragg scattering mechanism decreases monotonously with the increase of the period size, so it is difficult to obtain a low-frequency bandgap under the condition of a small period size, and the materi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10K11/162
Inventor 胡博杨德森时胜国时洁朱中锐张揽月孙玉方尔正王开举
Owner HARBIN ENG UNIV
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