阅读说明：本技术 带隙可调的拉胀声子晶体、应用及减振装置 (Band gap adjustable auxetic phononic crystal, application and vibration damping device ) 是由 费翔 颜学俊 卢明辉 徐晓东 陈延峰 钱斯文 于 2020-12-10 设计创作，主要内容包括：本申请涉及一种带隙可调的拉胀声子晶体、应用及减振装置。该带隙可调的拉胀声子晶体包括多个周期排布的三维反手性结构单元,三维反手性结构单元包括多个立方体,每个立方体的各表面均连接有连杆；拉胀声子晶体中,相邻两个立方体的相对面上的连杆相互连接,且该两个立方体位于该相互连接的连杆的同侧；及,拉胀声子晶体沿频率增加方向依次包括第一带隙和第二带隙,第二带隙宽于第一带隙,并且,在外力作用下拉胀声子晶体发生应变,第二带隙的宽度改变。上述拉胀声子晶体具有中高频的宽带隙,带隙可调,并且重量轻、体积小、易制备。(The application relates to an auxetic phononic crystal with adjustable band gap, application and a vibration damping device. The band gap adjustable auxetic phononic crystal comprises a plurality of periodically arranged three-dimensional anti-chiral structural units, each three-dimensional anti-chiral structural unit comprises a plurality of cubes, and each surface of each cube is connected with a connecting rod; in the auxetic phononic crystal, connecting rods on opposite surfaces of two adjacent cubes are connected with each other, and the two cubes are positioned on the same side of the connecting rods which are connected with each other; and the auxetic phononic crystal sequentially comprises a first band gap and a second band gap along the frequency increasing direction, the second band gap is wider than the first band gap, the auxetic phononic crystal is strained under the action of external force, and the width of the second band gap is changed. The auxetic phonon crystal has a wide band gap at medium and high frequencies, is adjustable in band gap, light in weight, small in size and easy to prepare.)

1. An auxetic phononic crystal with adjustable band gap is characterized in that,

the auxetic phononic crystal comprises a plurality of periodically arranged three-dimensional anti-chiral structural units, each three-dimensional anti-chiral structural unit comprises a plurality of cubes, and each surface of each cube is connected with a connecting rod;

in the auxetic phononic crystal, connecting rods on opposite surfaces of two adjacent cubes are connected with each other, and the two cubes are positioned on the same side of the connecting rods which are connected with each other;

and a process for the preparation of a coating,

the auxetic photonic crystal sequentially comprises a first band gap and a second band gap along the frequency increasing direction, the second band gap is wider than the first band gap, the auxetic photonic crystal is strained under the action of external force, and the width of the second band gap is changed.

2. The auxetic photonic crystal according to claim 1, wherein the auxetic photonic crystal is subjected to a tensile force, and the width of the second band gap increases; the auxetic phononic crystal is under the action of compressive force, and the width of the second band gap is reduced.

3. The auxetic phononic crystal of claim 2,

the auxetic phononic crystal is under the action of tensile force, and the lower boundary of the second band gap moves towards the direction close to the first band gap;

the auxetic phononic crystal is under the action of compressive force, and the lower boundary of the second band gap moves towards the direction far away from the first band gap;

wherein a lower boundary of the second bandgap represents a boundary of the second bandgap proximate to the first bandgap.

4. The auxetic phononic crystal of claim 3, wherein a distance of movement of the lower boundary of the second bandgap for unit length of elongation of the auxetic phononic crystal is greater than a distance of movement of the lower boundary of the second bandgap for unit length of compression of the auxetic phononic crystal.

5. The auxetic phononic crystal of claim 1, wherein one end of the rod is connected at a corner point position of the cube surface.

6. The auxetic phononic crystal of claim 1, wherein a cross-section of the connecting rod is square; and the number of the first and second electrodes,

the side length of the cross section of the connecting rod is less than one fifth of the side length of the cube, and the length of the connecting rod is greater than one third of the side length of the cube.

7. The auxetic phononic crystal of any of claims 1-6 wherein the cube and the connecting rod are made of the same material.

8. The auxetic phononic crystal of claim 7, wherein the auxetic phononic crystal is integrally formed.

9. Use of an auxetic phononic crystal according to any of claims 1-8,

used for obstructing the transmission of elastic waves with the frequency ranging from 4850Hz to 11700 Hz; or the like, or, alternatively,

used for blocking the transmission of elastic waves with the frequency ranging from 4500Hz to 11500 Hz.

10. A vibration damping device comprising an auxetic phonon crystal according to any of claims 1-8.

Technical Field

The invention relates to the technical field of metamaterials, in particular to an auxetic phononic crystal with adjustable band gap, application and a vibration damping device.

Background

With the development of modern industry, the problems of noise and vibration in human living environment are increasingly prominent. On one hand, how to realize vibration reduction and noise reduction of electromechanical equipment and ensure that the electromechanical equipment works safely and in a long service life is a problem to be solved; on the other hand, the vibration problem caused by the operation of large-scale mechanical equipment not only can cause irreversible damage to buildings where people live, but also can cause physical health influence on human beings. Finding effective methods for suppressing vibration and reducing noise has become an important subject of industrial development at present.

However, most of the current vibration and noise reduction materials are conventional damping materials, and generally comprise a single layer, a hollow structure, or a sandwich structure which relies on filling some high-performance fibers and high-damping polymers to perform a mixing stroke by some special means. These designs and preparations are based on the mass law and the internal damping law of the materials, and their effects are not obvious, and it is difficult to design a structure that blocks and absorbs elastic waves of a specific frequency.

Disclosure of Invention

Based on this, it is necessary to provide an improved auxetic phononic crystal for solving the problems of poor damping effect and non-adjustable damping frequency of the conventional damping and noise-reducing material.

The band gap adjustable auxetic phononic crystal comprises a plurality of periodically arranged three-dimensional anti-chiral structural units, each three-dimensional anti-chiral structural unit comprises a plurality of cubes, and each surface of each cube is connected with a connecting rod;

in the auxetic phononic crystal, connecting rods on opposite surfaces of two adjacent cubes are connected with each other, and the two cubes are positioned on the same side of the connecting rods which are connected with each other;

and a process for the preparation of a coating,

the auxetic photonic crystal sequentially comprises a first band gap and a second band gap along the frequency increasing direction, the second band gap is wider than the first band gap, the auxetic photonic crystal is strained under the action of external force, and the width of the second band gap is changed.

The auxetic photonic crystal has a second band gap with higher frequency and wider frequency band range, so that elastic waves in a medium-high frequency range can be well blocked, and better vibration and noise reduction effects can be realized; and when the auxetic photonic crystal is subjected to strain caused by external force, the width of the second band gap is correspondingly changed, so that the effective adjustment of vibration reduction frequency is realized, the flexibility of the vibration reduction and noise reduction structure design is improved, and the vibration reduction and noise reduction requirements of different users are met.

In one embodiment, the auxetic phononic crystal is subjected to a tensile force, and the width of the second band gap is increased; the auxetic phononic crystal is under the action of compressive force, and the width of the second band gap is reduced.

In one embodiment, the auxetic phononic crystal is subjected to a tensile force, and the lower boundary of the second band gap moves towards a direction close to the first band gap; the auxetic phononic crystal is under the action of compressive force, and the lower boundary of the second band gap moves towards the direction far away from the first band gap; wherein a lower boundary of the second bandgap represents a boundary of the second bandgap proximate to the first bandgap.

In one embodiment, the distance that the lower boundary of the second bandgap moves when the auxetic photonic crystal stretches a unit length is greater than the distance that the lower boundary of the second bandgap moves when the auxetic photonic crystal compresses a unit length.

In one embodiment, one end of the connecting rod is connected at the position of a corner point of the surface of the cube.

In one embodiment, the cross section of the connecting rod is square; and the side length of the cross section of the connecting rod is less than one fifth of the side length of the cube, and the length of the connecting rod is greater than one third of the side length of the cube.

In one embodiment, the cube and the connecting rod are made of the same material.

In one embodiment, the auxetic phononic crystal is integrally formed.

The application also provides an application of the auxetic phononic crystal.

Use of an auxetic phononic crystal as hereinbefore described to block propagation of elastic waves having a frequency in the range 4850Hz to 11700 Hz; or, for blocking the propagation of elastic waves having a frequency in the range of 4500 Hz-11500 Hz.

The application of the auxetic phononic crystal can be used for blocking the transmission of elastic waves in a medium-high frequency range, and the auxetic phononic crystal can be used for blocking the transmission of elastic waves in different frequency ranges by applying a tensile force or a compressive force to the auxetic phononic crystal.

The application also provides a vibration damping device.

A vibration damping device comprising an auxetic phononic crystal as hereinbefore described.

The vibration damper is prepared by using the auxetic phononic crystal, can realize the elastic wave blocking and absorbing effect with medium and high frequency width and adjustable frequency range, and has wide application prospect.

Drawings

Fig. 1 (a) is a model structure diagram according to an embodiment of the present application;

FIG. 1 (b) is a schematic block diagram of an embodiment of the present application;

FIG. 2 (a) is a finite element simulation of auxetic properties for an embodiment of the present application;

fig. 2 (b) is a mechanical experiment graph of auxetic properties according to an embodiment of the present application;

FIG. 3 (a) is a schematic partial band diagram comprising a first band gap and a second band gap when an embodiment of the present application is undeformed;

FIG. 3 (b) is a schematic partial band diagram comprising a first bandgap and a second bandgap when strained by a tensile force according to an embodiment of the present application;

fig. 4 shows (a), (b), (c) and (d) respectively a mode corresponding to a lower boundary of a first bandgap, a mode corresponding to an upper boundary of the first bandgap, a mode corresponding to a lower boundary of a second bandgap and a mode corresponding to an upper boundary of the second bandgap when the embodiment of the present application is not deformed;

fig. 5 shows (a), (b), (c) and (d) respectively a mode corresponding to the lower boundary of the first band gap, a mode corresponding to the upper boundary of the first band gap, a mode corresponding to the lower boundary of the second band gap and a mode corresponding to the upper boundary of the second band gap when an embodiment of the present application is strained by a tensile force;

FIG. 6 shows the magnitude of the frequency corresponding to the lower boundary of the second bandgap of an embodiment of the present application as a function of the tensile and compressive strain of the auxetic photonic crystal;

FIG. 7 is a graph of a simulation of the transmission spectrum of elastic waves under different strains according to an embodiment of the present application;

fig. 8 shows a schematic diagram of vibration distribution of elastic waves with band gap outer frequency and band gap inner frequency incident to an embodiment of the present application.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "left," "right," "upper," "lower," "front," "rear," "circumferential," and the like are based on the orientation or positional relationship shown in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The phononic crystal has acoustic band gap, that is, elastic wave can not pass through the phononic crystal in the frequency range of the band gap, so that the phononic crystal has wide application prospect in the aspects of vibration suppression and acoustic wave absorption. In recent years, researchers at home and abroad have made a lot of research on finding a phononic crystal structure having a band gap. In 2000, Liuzheng \29495, a phononic crystal designed by utilizing a local resonance mechanism can control elastic waves with the wavelength being two orders of magnitude larger than the size of a crystal lattice. Chinese patent CN 206946932U also describes a method for realizing a wide low-frequency band gap by using a three-dimensional local resonance type phonon crystal. However, the phononic crystals of the invention not only have the problem of not wide enough band gap frequency, but also have the defects of large matrix mass and complex traditional machining.

In 2016, Zhenghui and the like research band gaps and transmission spectra of two-dimensional chiral structures, and found that the structures have band gaps and lower elastic wave transmittance at certain frequencies, Korner prepared a three-dimensional phonon crystal of a single-phase material capable of being 3D printed, and in 2017, Corigliano and the like designed a three-dimensional phonon crystal with a low-frequency ultra-wide band gap by using a vibration mode separation method.

In view of the above problems, the present application provides an auxetic phonon crystal having a wide band gap at a medium-high frequency and an adjustable band gap width. The auxetic phononic crystal also has the advantages of simple preparation, small mass, small volume and the like, thereby having wide application prospect.

Referring to fig. 1, the auxetic phononic crystal of the present application includes a plurality of periodically arranged three-dimensional anti-chiral structural units, each three-dimensional anti-chiral structural unit includes a plurality of cubes 1, and each surface of each cube 1 is connected with a connecting rod 2; in the auxetic phononic crystal, the connecting rods 2 on the opposite faces of two adjacent cubes 1 are connected with each other, and the two cubes 1 are located on the same side of the connecting rods 2 connected with each other.

A Chiral (Chiral) structure is a structure that is widely found in nature, and any shape that does not coincide with its own mirror image by translation we can refer to it as Chiral. Chiral structures can also be used to design auxetic metamaterials. The typical chiral auxetic structure comprises a circle at the center, the peripheral circles are connected with the central circle through rod units at the tangent lines, when a pressure is applied, the rotation of the central circle causes the rod units to generate a pulling force towards the center, the two side circles contract inwards to generate a negative Poisson ratio, and different chiral structures can be designed by changing the number of the rod units connected with the central circle. If the two circles connected by the rod units are located on the same side of the rod units, the structure may be said to be an anti-handed structure.

Taking fig. 1 as an example, the auxetic phononic crystal is formed by periodically extending a plurality of three-dimensional anti-chiral structural units along the x direction, the y direction and the z direction, and can be used for constructing a solid body in a 3D printing mode. Specifically, the three-dimensional anti-chiral structural unit comprises eight cubes 1, six faces of each cube 1 are respectively connected with a connecting rod 2, and the cross section of each connecting rod 2 is square. Each cube 1 has six cubes 1 adjacent to it, the links 2 on opposite sides of any two adjacent cubes 1 are interconnected, and the two adjacent cubes 1 are located on the same side of the interconnected links 2, thereby forming a three-dimensional anti-chiral structure. If the three-dimensional anti-chiral structure is observed along three orthogonal directions, the view in each direction can be found to be in an anti-quadruple chiral shape.

Fig. 2 shows a finite element simulation diagram and a mechanical experiment diagram of the auxetic photonic crystal under pressure. It can be seen that upon application of pressure, the cube 1 rotates and the connecting rods 2 bend, causing the overall structure of the auxetic phononic crystal to contract inwards, thereby exhibiting good auxetic properties. In another embodiment, the cube 1 may be changed to a rectangular parallelepiped or other polyhedron, which is not limited in this application.

Furthermore, the auxetic photonic crystal sequentially comprises a first band gap and a second band gap along the frequency increasing direction, the second band gap is wider than the first band gap, and the auxetic photonic crystal is strained under the action of external force, so that the width of the second band gap is changed. Wherein, the strain refers to the local relative deformation of the object under the action of factors such as external force and non-uniform temperature field. It can be understood that elastic waves with frequencies at the first and second band gaps cannot pass through the auxetic phonon crystal.

Specifically, taking the structure shown in fig. 1 as an example, the side length of each cube 1 is a, the side length of the cross section of each connecting rod 2 is t, the center distance between two adjacent cubes 1 is l, a is 18mm, t is 1.8mm, l is 30mm, and the materials of each cube 1 and each connecting rod 2 are made of resin, wherein the young's modulus E of the resin is 1.8GPa, and the density is 1150kg/m³The Poisson ratio is 0.4, and then the partial band diagram of the auxetic phononic crystal can be calculated by software. Referring to fig. 3, wherein the abscissa represents the wave vector, the ordinate represents the frequency, and the light gray portion represents the band gap, as can be seen from the graph (a) in fig. 3, in the case that the auxetic photonic crystal is not strained by the force, the auxetic photonic crystal has a narrower first band gap and a wider second band gap in sequence along the frequency increasing direction, the corresponding band gaps have widths of 1.15KHz to 2.15KHz and 4.84KHz to 11.72KHz, respectively, and the corresponding normalized frequencies are 0.055 to 0.103 and 0.232 to 0.562, respectively, thereby indicating that the auxetic photonic crystal shown in fig. 1 has a higher band gap at the mid-high frequency bandA wide band gap. Further, as can be seen from the graph (b), when the tensile force of the auxetic photonic crystal is strained by 5mm, the band gap width of the first band gap is 1.22KHz to 1.96KHz, and the band gap width of the second band gap is 4.42KHz to 11.5KHz, thereby indicating that when the auxetic photonic crystal is strained by an external force, the width of the second band gap changes accordingly.

Fig. 4 shows the vibration modes of the auxetic photonic crystal at the upper and lower boundaries of the first and second band gaps when no strain occurs, and fig. 5 shows the vibration modes of the auxetic photonic crystal at the upper and lower boundaries of the first and second band gaps when strain occurs by 5mm, wherein the lower boundary of the first band gap represents the boundary where the first band gap is far from the second band gap (the boundary represents the lowest frequency), the upper boundary of the first band gap represents the boundary where the first band gap is close to the second band gap, the lower boundary of the second band gap represents the boundary where the second band gap is close to the first band gap, and the upper boundary of the second band gap represents the boundary where the second band gap is far from the first band gap (the boundary has the highest frequency). The result shows that the vibration modes at the upper and lower boundaries of the same band gap are different, and the corresponding effective rigidity is greatly different, so that a wider band gap can be formed.

The auxetic photonic crystal has a second band gap with higher frequency and wider frequency band range, so that elastic waves in a medium-high frequency range can be well blocked, and better vibration and noise reduction effects can be realized; and when the auxetic photonic crystal is subjected to strain caused by external force, the width of the second band gap is correspondingly changed, so that the effective adjustment of vibration reduction frequency is realized, the flexibility of the vibration reduction and noise reduction structure design is improved, and the vibration reduction and noise reduction requirements of different users are met.

In an exemplary embodiment, the auxetic photonic crystal is subjected to a tensile force (stretch), and the width of the second bandgap increases; the auxetic phononic crystal is subjected to a compressive force (compression), and the width of the second band gap is reduced. Specifically, the auxetic phononic crystal is acted by a tensile force, and the lower boundary of the second band gap moves towards the direction close to the first band gap; when the auxetic phononic crystal is subjected to a compressive force, the lower boundary of the second band gap moves towards a direction far away from the first band gap.

Specifically, as shown in fig. 6, the abscissa represents the strain of the auxetic photonic crystal, and the ordinate represents the frequency corresponding to the lower boundary of the second band gap. As can be seen from fig. 6, if the strain is equal to 0, it means that no external force is applied to the auxetic photonic crystal, and the frequency corresponding to the lower boundary of the second bandgap is about 4750 Hz; if the strain is greater than 0, the stretching phononic crystal is subjected to stretching force (stretch), the frequency corresponding to the lower boundary of the second band gap is smaller than 4750Hz, the lower boundary of the second band gap moves downwards, and the second band gap is widened; if the strain is less than 0, the tensile phononic crystal is subjected to compressive force (compression), and the frequency corresponding to the lower boundary of the second band gap is greater than 4750Hz, the lower boundary of the second band gap moves upwards, and the second band gap becomes narrow.

The width of the second band gap can be adjusted more simply, conveniently and effectively by controlling the movement of the lower boundary of the second band gap, so that the frequency requirement of vibration reduction and noise reduction can be met.

In an exemplary embodiment, the distance of movement of the lower boundary of the second bandgap when the auxetic photonic crystal stretches a unit length is greater than the distance of movement of the lower boundary of the second bandgap when the auxetic photonic crystal compresses a unit length.

With continued reference to fig. 6, the slope of the change in frequency of the lower boundary of the second bandgap is significantly greater when the strain is greater than 0 than when the strain is less than 0, so that the effect of compressive strain on the second bandgap is significantly less than the effect of tensile strain on the second bandgap. Therefore, when the width of the second band gap is adjusted, if the adjustment range is required to be large, the adjustment can be performed by selectively applying a tensile force; if the magnitude of the adjustment is small, the application of compressive force can be selected for adjustment.

In an exemplary embodiment, as shown in FIG. 1, one end of the tie rod is connected at the corner point of the cube surface. Specifically, the corner position represents an area near the intersection of two edges on each face of the cube 1. For example, the area near the intersection point may be an area represented by a quarter circle that coincides with the surface of the cube and is formed by rounding the intersection point with a radius of 0 to 30% of the side length, and this is not particularly limited in the present application as long as the area is sufficiently close to the intersection point of the surface of the cube. Through the arrangement, when the phononic crystal is subjected to external force, the cube 1 rotates more fully, and the connecting rod 2 bends more obviously, so that the phononic crystal has better auxetic property.

In the exemplary embodiment, the cross section of the connecting rod 2 is square; and the side length of the cross section of the connecting rod 2 is less than one fifth of the side length of the cube 1, and the length of the connecting rod 2 is more than one third of the side length of the cube 1. Can guarantee through above-mentioned setting that the auxetic photonic crystal possesses the band gap of broad, make the band gap width obtain the adjustment under the exogenic action simultaneously to further promote the damping noise reduction effect of this auxetic photonic crystal, satisfy different users' damping noise reduction demand. When any length relation does not satisfy, the energy band characteristics of the auxetic photonic crystal cannot be guaranteed, for example, the band gap number is reduced, or the band gap width is narrowed, or the band gap is not adjustable, or the band gap directly disappears, so that it is difficult to realize the required vibration reduction and noise reduction effects by using the auxetic photonic crystal.

In an exemplary embodiment, the cube and the connecting rod are made of the same material. For example, nylon, resin or pure titanium may be used. The nylon material has good recoverability, and the pure titanium sample has higher strength. The vibration and noise reduction material with better effect is prepared by using the single material, so that the auxetic phononic crystal has very wide application prospect in the field of multifunctional materials. In addition, the density of the material is small, and the volume of the auxetic phononic crystal is small, so that the vibration-damping noise-reducing device with light weight and small volume is favorably prepared.

In an exemplary embodiment, a plurality of three-dimensional inverse-handed structures in the auxetic photonic crystal can be integrally formed through 3D printing, so that the preparation is easy, and the condition of industrial production is met.

The application also provides an application of the auxetic phononic crystal as described in the foregoing, for blocking propagation of elastic waves with a frequency in a range of 4850Hz to 11700 Hz; or, for blocking the propagation of elastic waves having a frequency in the range of 4500 Hz-11500 Hz.

Specifically, referring to fig. 7, fig. 7 is a graph showing a simulation of a transmission spectrum of an elastic wave when different strains occur according to an embodiment of the present application, where an abscissa represents a frequency of an incident elastic wave and an ordinate represents a transmission coefficient of the elastic wave. When no external force (unformed) is applied, the width of the second band gap is 4850 Hz-11700 Hz, the elastic waves in the frequency range have lower transmission coefficients, and the lowest transmission coefficient can reach-200 dB; after external force is applied, in order to conveniently observe the boundary movement of the second band gap, the transmission coefficient (-40dB) corresponding to the frequency of the lower boundary of the second band gap when external force is not applied is taken as the starting standard of the lower boundary of the second band gap, so that when the auxetic photonic crystal generates tensile strain of 2mm, 10mm and 15mm, the lower boundary of the second band gap obviously moves towards the direction close to the first band gap (leftwards moves in the figure), the second band gap is widened, the width is 4500 Hz-11500 Hz, the elastic waves in the frequency range also have lower transmission coefficients, and the lowest transmission coefficient can reach-220 dB. Therefore, the two frequency bands have good blocking effect on the elastic waves.

Further, referring to fig. 8, fig. 8 shows a schematic diagram of vibration distribution of elastic waves with band gap outer frequency and band gap inner frequency incident to an embodiment of the present application. It can be seen that when the elastic wave is incident at a frequency (3000Hz) outside the band gap, the entire structure of the auxetic phononic crystal vibrates, and the stress field is global; and when the elastic wave is incident at a frequency (5000Hz) within the band gap, the elastic wave is localized inside the auxetic phonon crystal, so that the elastic wave is isolated.

The application of the auxetic phononic crystal can be used for blocking the elastic wave transmission in a wide frequency range of medium and high frequencies, and the auxetic phononic crystal can be used for blocking the elastic wave transmission in different frequency ranges by applying a tensile force or a compression force to the auxetic phononic crystal.

The present application also provides a vibration damping device comprising an auxetic phononic crystal as described above.

The vibration damper is prepared by using the auxetic phononic crystal, can realize the elastic wave blocking and absorbing effect with medium and high frequency width and adjustable frequency range, and has wide application prospect. For example, a porous material having both impact resistance and vibration isolation can be prepared.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.