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Variable-section acoustic metamaterial beam with double-degree-of-freedom local resonance units

An acoustic metamaterial and local resonance technology, applied in the direction of joists, girders, truss beams, etc., can solve the problems of narrow band gap bandwidth and small effective frequency range of local resonance, and achieve firm and reliable bonding, low cost, Break through the effect of narrow bandwidth

Active Publication Date: 2020-01-24
HARBIN ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem in the prior art that the local resonance bandgap bandwidth of equal-section acoustic metamaterials is narrow, resulting in a small effective frequency range for vibration and noise reduction, which limits the practical application of acoustic metamaterials in engineering, it further provides A variable-section acoustic metamaterial beam with a dual-degree-of-freedom local resonance element

Method used

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  • Variable-section acoustic metamaterial beam with double-degree-of-freedom local resonance units
  • Variable-section acoustic metamaterial beam with double-degree-of-freedom local resonance units
  • Variable-section acoustic metamaterial beam with double-degree-of-freedom local resonance units

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specific Embodiment approach 1

[0030] Specific implementation mode one: combine Figure 1 to Figure 4 To illustrate this embodiment, the variable-section acoustic metamaterial beam with a dual-degree-of-freedom local resonance unit includes M stepped beam assemblies, where M is a positive integer, and the M stepped beam assemblies are arranged in sequence along the long direction of the length. A fixed connection between two adjacent stepped beam components.

[0031] In this embodiment, when the length of the stepped beam assembly, the ratio of cross-sectional dimensions, and the length ratio of the thin beam section to the thick beam section are fixed, the rubber columns and mass blocks with various structural parameters in the stepped beam assembly can be designed to be bonded into different The local resonance unit, adjust the natural frequency of the local resonance unit, and then change the position of the local resonance bandgap, and realize the widening of the local resonance bandgap through the inte...

specific Embodiment approach 2

[0032] Specific implementation mode two: combination Figure 5 and Figure 8 Describe this embodiment. This embodiment is to further limit the stepped beam assembly in Embodiment 1. In this embodiment, the stepped beam assembly includes a stepped beam main body 1 and a two-degree-of-freedom local resonance unit 2. Each two-degree-of-freedom local resonance unit 2 is fixedly connected to a stepped beam main body 1, and the stepped beam main bodies 1 in two adjacent stepped beam assemblies are fixedly connected. Other compositions and connection methods are the same as those in Embodiment 1.

[0033] In this embodiment, the fixed connection mode of the ladder beam main body 1 in two adjacent ladder beam assemblies is bonding, which is convenient for increasing or decreasing the number of ladder beam assemblies according to experiments or practical applications, and at the same time, it is bonded to ensure firmness. At the same time, the material properties of the stepped beam ...

specific Embodiment approach 3

[0034] Specific implementation mode three: combination Figure 5 Describe this embodiment. This embodiment is to further limit the stepped beam main body 1 described in the second specific embodiment. In this embodiment, the stepped beam main body 1 includes a thin beam section 11 and a thick beam section 12. Both the beam section 11 and the thick beam section 12 are cuboids, one end of the thin beam section 11 and one end of the thick beam section 12 are integrally arranged, and the other of the thick beam section 12 in the previous stepped beam main body 1 of the two adjacent stepped beam main bodies 1 One end is fixedly connected with the other end of the thin beam section 11 in the latter ladder beam main body 1 . Other compositions and connection methods are the same as those in Embodiment 1.

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Abstract

The invention discloses a variable-section acoustic metamaterial beam with double-degree-of-freedom local resonance units, and belongs to the technical field of mechanical vibration and noise control.The variable-section acoustic metamaterial beam is mainly used for solving the problems that a local resonance band gap of an equal-section acoustic metamaterial in the prior art is small in band width, consequently, the effective frequency range of vibration reduction and noise reduction of the equal-section acoustic metamaterial is small, and actual application of the acoustic metamaterial to engineering is limited. The variable-section acoustic metamaterial beam with the double-degree-of-freedom local resonance units comprises M step beam assemblies, wherein M is a positive integer, the Mstep beam assemblies are sequentially arranged in the length direction, every two step beam assemblies are fixedly connected, and each step beam assembly comprises a step beam body and the corresponding double-degree-of-freedom local resonance unit. The variable-section acoustic metamaterial beam is mainly applied to research of vibration reduction and noise reduction properties of a broadband forbidden band of the acoustic metamaterial.

Description

technical field [0001] The invention belongs to the technical field of mechanical vibration and noise control, in particular to a variable-section acoustic metamaterial beam with a dual-degree-of-freedom local resonance unit. Background technique [0002] Acoustic metamaterials are local resonant phononic crystals (periodic structures) with extraordinary physical properties (negative mass density, negative elastic modulus, etc.) that are completely different from those in nature. It can generate a low-frequency local resonance bandgap in the sub-wavelength band of the structure size, which can realize the isolation of low-frequency vibration noise through small-scale structures. However, the local resonance bandgap bandwidth of traditional equal-section acoustic metamaterials is narrow, resulting in a small effective frequency range for vibration and noise reduction. This bottleneck greatly limits the wide application of acoustic metamaterials in engineering practice. Cont...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E04C3/02E04B1/84
CPCE04B1/8404E04B2001/8461E04C3/02
Inventor 温舒瑞李凤明熊远皓郝帅民
Owner HARBIN ENG UNIV