Three-negative elastic wave metamaterial with wide forbidden band

A metamaterial, elastic wave technology, applied in the functional characteristics of springs/shock absorbers, spring assemblies composed of several springs, springs, etc., can solve the problem of less research and development of practical functional devices, and has not yet entered the stage of large-scale application, etc. problem, to achieve the effect of increasing the frequency range

Pending Publication Date: 2020-05-08
SOUTHEAST UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

Most of its research is theoretical research, and the research and development of practical functional devices is less, and the developed functional devices are generally only used in laboratories, and have not yet entered the stage of large-scale application

Method used

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  • Three-negative elastic wave metamaterial with wide forbidden band
  • Three-negative elastic wave metamaterial with wide forbidden band
  • Three-negative elastic wave metamaterial with wide forbidden band

Examples

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Embodiment example 1

[0025] Implementation Case 1: If image 3 as shown, image 3 (a) is a design diagram of a triple negative elastic wave metamaterial unit cell with a wide band gap, in which a=6mm, R=1mm, D 1 = 1.6mm, D 2 = 0.6mm, D 3 = 0.8mm, D 4 = 0.3mm. image 3 (b) is the energy band structure diagram of the unit cell, and the three negative parameters appear in the overlapping parts of the fifth and sixth negative energy bands (it can be proved by observing the displacement eigenfields of these two energy bands). The second forbidden band width of the unit cell is about 4.5kHz, which is higher than the similar forbidden band width. image 3 (c) is a three-negative elastic wave metamaterial belt composed of ten such unit cells. The transmission curve calculated according to this model is as follows image 3 As shown in (d), the transmission rate of longitudinal wave and shear wave is relatively high in the overlapping part of the fifth and sixth energy bands, while the transmission ra...

Embodiment example 2

[0026] Implementation Case 2: If Figure 4 as shown, Figure 4 (a) is a functionally graded material that can bend the elastic wave path and propagate in an arc. It can be seen that the first layer is composed of negative refraction metamaterials. Bundle figure 2 The unit cell in Figure 4 The first layer of functionally graded material in (a), forming a new functionally graded material such as Figure 4 (b) shown. This functionally graded material composed of three negative elastic wave metamaterials has a forbidden band, which can prevent the propagation of elastic waves within the forbidden band frequency, and can propagate elastic waves at certain frequencies that cannot be prevented by the forbidden band. Path, to avoid it from affecting the target that needs to be protected, so the functionally graded material can use its forbidden band and passband to jointly isolate vibration.

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Abstract

The invention discloses a three-negative elastic wave metamaterial with a wide forbidden band. The three-negative elastic wave metamaterial comprises N unit cells, wherein each unit cell is of a two-dimensional structure and is square; a base material is foam; a round hole is formed in the center of the base material; four elliptical holes are formed around the round hole; the four elliptical holes are filled with scatterer metal tungsten, but the elliptical holes cannot be filled with scatterers; and the whole unit cell is of a central symmetry structure. The elastic wave metamaterial can simultaneously achieve equivalent negative mass density, equivalent negative volume modulus and equivalent negative shear modulus within the same frequency range, so that negative refraction of transverse waves and longitudinal waves of elastic waves is achieved within the same frequency range; and meanwhile, the elastic wave metamaterial also has the relatively wide forbidden band. The material canbe used for designing functional devices and gradient materials for regulating and controlling the elastic waves, and can also be used for vibration isolation and sound insulation of mechanical equipment and building structures.

Description

technical field [0001] The invention belongs to the field of vibration reduction, and in particular relates to an elastic wave metamaterial with equivalent negative mass density, equivalent negative bulk modulus, and equivalent negative shear modulus within the same frequency range. Background technique [0002] At present, how to control vibration is a significant problem in the research fields of machinery, civil engineering, and instruments. For example, resonance will cause the components to fail. In addition, frequent vibrations will accelerate the fatigue damage of metal components. Especially for precision instruments, to ensure their accuracy, it is necessary to ensure that they are not disturbed by vibration. All vibrating objects are making sound, and noise will affect people's quality of life and physical and mental health. Therefore, the research on vibration isolation and vibration reduction is of great significance. [0003] The theoretical basis of elastic w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F16F3/00F16F3/12
CPCF16F3/00F16F3/12F16F2224/0225F16F2224/025F16F2228/04F16F2230/02
Inventor 万水王潇符俊东周鹏申纪伟苏强年玉泽李夏元黄牧允
Owner SOUTHEAST UNIV
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