CN111524496B - Acoustic metamaterial and acoustic device based on impedance matching effect - Google Patents
Acoustic metamaterial and acoustic device based on impedance matching effect Download PDFInfo
- Publication number
- CN111524496B CN111524496B CN202010365374.9A CN202010365374A CN111524496B CN 111524496 B CN111524496 B CN 111524496B CN 202010365374 A CN202010365374 A CN 202010365374A CN 111524496 B CN111524496 B CN 111524496B
- Authority
- CN
- China
- Prior art keywords
- boundary material
- hard boundary
- hard
- acoustic
- impedance matching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
Abstract
The application provides an acoustic metamaterial and an acoustic device based on an impedance matching effect. The acoustic metamaterial comprises a plurality of microstructures, wherein the microstructures are plane symmetrical structures; the microstructure is formed by arranging a plurality of groups of hard boundary material structures with sound wave incidence gaps along a preset axis, and the symmetry plane of the microstructure is perpendicular to the preset axis; and the plurality of sets of hard boundary material structures includes at least two types of hard boundary material structures having different effective sound speeds. The acoustic metamaterial based on the impedance matching effect can enable incident sound waves to pass through the hard boundary material in a wide working frequency range in a wide angle and almost without reflection, so that the problem of impedance mismatch of the traditional hard boundary material is solved, and the application range of some common hard boundary materials in acoustic engineering in daily life is widened.
Description
Technical Field
The application relates to the technical field of acoustics, in particular to an acoustic metamaterial and an acoustic device based on an impedance matching effect.
Background
Impedance is a very important issue in the acoustic field. Acoustic impedance is generally defined as the product of mass density and sound velocity or the ratio of sound pressure intensity to particle velocity. Acoustic impedance describes the resistance encountered by an acoustic wave as it passes through a material. When an acoustic wave is incident from one material to the other, if there is an impedance difference between the two materials, reflected waves are inevitably generated, except for the Fabry-perot resonance at a specific frequency or the zero reflection achieved by incidence at a specific angle (brewster angle).
In daily life, almost all solid materials (e.g., glass, resin, plastic, etc.) are sonic hard boundary materials (simply referred to as hard boundary materials). When sound waves are incident from air onto hard boundary materials, they are significantly reflected due to the very mismatch of their acoustic impedances to air, resulting in reverberation and scattering, thus limiting the engineering application range of these solid materials.
Disclosure of Invention
Based on this, it is necessary to provide an improved acoustic metamaterial for the problem of significant reflection of sound waves on hard boundary materials.
An acoustic metamaterial based on an impedance matching effect, which is used for weakening or eliminating sound wave reflection, comprises a plurality of microstructures, and the microstructures are plane symmetrical structures; the microstructure is formed by arranging a plurality of groups of hard boundary material structures with sound wave incidence gaps along a preset axis, and the symmetry plane of the microstructure is perpendicular to the preset axis; and the plurality of sets of hard boundary material structures includes at least two types of hard boundary material structures having different effective sound speeds.
The acoustic metamaterial based on the impedance matching effect can enable incident sound waves to pass through the hard boundary material in a wide working frequency range in a wide angle and almost without reflection, so that the problem of impedance mismatch of the traditional hard boundary material is solved, and the application range of some common hard boundary materials (such as glass, resin, plastic and the like) in acoustic engineering such as shock absorption and noise reduction, sonar detection and the like in daily life is widened.
In one embodiment, the plurality of sets of hard boundary material structures comprises:
two groups of first-class hard boundary material structures are respectively arranged on two sides of the microstructure; the method comprises the steps of,
the second type of hard boundary material structures are arranged between the two first type of hard boundary material structures, and the effective sound velocity of the second type of hard boundary material structures is smaller than that of the first type of hard boundary material structures.
The plane symmetry of the microstructure is realized through a simple symmetrical structure, and meanwhile, the effective sound velocity of the second-type hard boundary material structure is smaller than that of the first-type hard boundary material structure by regulating and controlling the structural parameters of the hard boundary materials in the second-type hard boundary material structure, so that the acoustic impedance matching theory under the symmetrical structure is satisfied.
In one embodiment, the first hard boundary material structure is formed by arranging a plurality of first hard boundary material units at intervals along the preset axis; the second hard boundary material structure is formed by arranging a plurality of second hard boundary material units at intervals along the preset axis.
The method is favorable for adjusting the sizes or the spacing distances of the hard boundary material units in various hard boundary material structures, so that the microstructure can better meet the acoustic impedance matching theory.
In one embodiment, the cross-sectional shape of the first hard border material element is circular, oval, square or diamond, and the cross-sectional shape of the second hard border material element is circular, oval, square or diamond.
The variety of the cross section shapes facilitates the preparation and selection of the hard boundary material units, expands the selection range of the materials and reduces the production and preparation cost.
In one embodiment, the first hard border material element is a hard border cylinder having a first diameter; the second hard border material unit is a hard border cylinder with a second diameter; wherein the first diameter is smaller than the second diameter.
Through the mode, the effective sound velocity of the second-type hard boundary material structure is smaller than that of the first-type hard boundary material structure, the cylinder is convenient to machine, the 3D printer is convenient to print, and the preparation cost can be further reduced. In addition, the effective sound velocity of the hard boundary material structure can be adjusted only by adjusting the diameter of the cylinder, so that the method is convenient and quick and is beneficial to engineering application.
In one embodiment, the spacing distance between each adjacent hard border material units is equal.
Therefore, the uneven sound velocity in the corresponding hard boundary material structure caused by the different sparse and dense arrangement of the hard boundary material units can be avoided, and the impedance matching effect of the acoustic metamaterial is further affected.
In one embodiment, the acoustic metamaterial is formed from the plurality of microstructures arranged in an array.
This is more advantageous for achieving wide angle impedance matching of the acoustic metamaterial 100, while also facilitating the preparation of the acoustic metamaterial.
In one embodiment, the acoustic metamaterial has a reflectivity of less than or equal to 1% for sound waves having a normalized frequency in the range of 0.6 to 0.78 and an incident angle of 0 to 40 °.
The acoustic metamaterial has a good reflection weakening or eliminating effect on incident sound waves with normalized frequency of 0.6-0.78 and incident angle of 0-40 degrees, and has a wider application prospect compared with the traditional sound wave anti-reflection device, and the frequency and angle range are greatly widened.
In one embodiment, the hard border material is at least one of plastic, glass, resin, metal, steel bar and concrete.
Therefore, the common materials in daily life can be utilized to prepare the acoustic metamaterial, so that the preparation cost is reduced, and the industrial production of the acoustic metamaterial is facilitated.
The application also provides an acoustic device.
An acoustic device comprising an acoustic metamaterial as described hereinbefore.
The acoustic device can be prepared from solid materials common in daily life, and can enable incident sound waves to pass through in a wide-angle and almost reflection-free mode in the working frequency range, so that the acoustic device has great application potential in the acoustic engineering fields of vibration reduction, noise reduction, sonar detection and the like.
Drawings
Fig. 1 (a) to (b) show an incident schematic view and a microstructure schematic view, respectively, according to an embodiment of the present application;
fig. 2 (a) to (c) show an incidence diagram, a transreflection graph, and a change diagram of reflectivity with an incidence angle and an acoustic frequency, respectively, according to an embodiment of the present application;
fig. 3 (a) to (c) show the incidence diagram, the transreflection graph, and the reflectance diagram with the incidence angle and the acoustic frequency, respectively, when only the class a material is used;
fig. 4 (a) to (c) show the incidence diagram, the transreflection graph, and the reflectance diagram with the incidence angle and the acoustic frequency, respectively, when only the B-type material is used;
fig. 5 (a) to (c) show reflection experiment curves and simulation curves of a class a material only and a class B material only at incidence angles of 10 °, 20 ° and 30 °, respectively, according to another embodiment of the present application.
Detailed Description
In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. The drawings illustrate preferred embodiments of the application. This application 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 "fixed 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. The terms "vertical," "horizontal," "left," "right," "upper," "lower," "front," "rear," "circumferential," and the like as used herein are based on the orientation or positional relationship shown in the drawings and are merely for convenience of description and to simplify the description, rather than to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.
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 application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The hard boundary material can theoretically represent that the normal sound pressure of the material surface is zero when the sound wave is incident, i.e. the sound wave is difficult to penetrate through the hard boundary material, and basically is reflected back by the hard boundary material. Hard boundary materials in daily life comprise glass, plastic, resin, metal, steel bars, concrete and the like, and the materials are very mismatched with air in air, so that sound waves are reflected back into the air when being incident on the materials, reverberation and scattering are caused, and the vibration and noise reduction of a house building are not facilitated. In addition, in some sonar detection projects, the position of the target object can be ascertained by utilizing the reflection of sound waves, but the target object cannot acquire the position of the sonar, and the unidirectionality cannot be reversed, so that the further development of the detection technology is limited.
In the prior art, no reflection phenomenon of sound waves at wide frequency and wide angle can not be realized by utilizing a hard boundary material. After analysis practices of the prior art and related acoustic engineering, the inventor confirms that the reflection problem of the hard boundary material is a novel field problem to be solved urgently. Accordingly, the discovery process of the above-described problems and the solutions to the above-described problems set forth below in the embodiments of the present application should be all contributions of the inventors to the present application in the process of the present application.
Firstly, the acoustic wave impedance matching effect in the application means that according to the non-local dispersion relation of the acoustic metamaterial, the acoustic metamaterial and an acoustic wave incident medium can be subjected to impedance matching in a certain frequency range, so that the phenomenon of reflection is reduced or even completely eliminated.
Referring to fig. 1 (a), the present application provides an acoustic metamaterial 100 made of a hard boundary material based on acoustic impedance matching theory, which can be used to reduce or eliminate reflection of acoustic waves on the hard boundary material. The acoustic metamaterial 100 can realize the effect of no reflection of sound waves with wide frequency and wide angle in the air, has a simple structure, is wide in material selection, and has wide application prospects.
With continued reference to fig. 1 (b), the acoustic metamaterial 100 includes a plurality of microstructures 10, wherein the microstructures 10 are plane symmetrical structures, have a symmetry plane M, and have a length a in a preset axis direction. The microstructure 10 is formed by arranging a plurality of groups of hard boundary material structures with sound wave incidence gaps 11 along a preset axis AX (parallel to the x direction), a symmetry plane M of the microstructure 10 is perpendicular to the preset axis AX, and the plurality of groups of hard boundary material structures comprise at least two groups of hard boundary material structures with different effective sound speeds.
Specifically, the hard boundary material structure in this embodiment is a composite material structure, and the filling rate (i.e. the volume ratio) of the hard boundary material in the hard boundary material structure determines the effective sound velocity of the hard boundary material structure. The greater the filling rate of the hard boundary material in the hard boundary material structure, the greater the acoustic impedance of the hard boundary material structure, and the smaller (slow) the effective sound velocity of the hard boundary material structure; conversely, the smaller the filling rate of the hard boundary material in the hard boundary material structure, the smaller the acoustic impedance of the hard boundary material structure, and the greater (faster) the effective sound velocity of the hard boundary material structure.
In addition, the microstructure 10 may be arranged in various manners, preferably, the array arrangement shown in the (a) diagram in fig. 1, so as to be more beneficial to realizing wide-angle impedance matching of the acoustic metamaterial 100, and also facilitate preparation of the acoustic metamaterial 100.
Further, as shown in the graph (b) of FIG. 1, along the x-direction, a plurality of diameters D A Form a first set of hard boundary material structures, a plurality of hard boundary cylinders having a diameter D B (D A ≠D B ) Forming a second set of hard boundary material structures from a plurality of hard boundary cylinders of diameter D A Form a third set of hard boundary material structures. The portions of the microstructure 10 formed by the three sets of hard boundary material structures on either side of the plane M form planar symmetry about the plane M (i.e., a plane parallel to the y-z plane). Of course, the hard boundary material structures may be not only three groups, but also a fourth group, a fifth group, a sixth group, etc., as long as the microstructure 10 integrally formed by a plurality of groups of hard boundary material structures satisfies plane symmetry and the symmetry plane M thereof is perpendicular to the preset axis AX, and the number of groups of hard boundary material structures is not limited.
When an external sound wave is incident on the acoustic metamaterial 100, the sound wave may enter the acoustic metamaterial 100 through the sound wave incident gaps 11 in each set of hard boundary material structures. Further, the materials, the sizes, the arrangement modes and the like of the hard boundary material units in each set of hard boundary material structures are adjusted according to the frequency of the incident sound wave, so that the effective sound velocity of each set of hard boundary material structures meets the impedance matching theory of the sound wave, and further perfect matching with the air impedance is realized, and at the moment, the reflectivity of the acoustic metamaterial 100 to the sound wave in a wide angle range is almost 0.
The above-mentioned acoustic metamaterial 100 can make incident sound pass through the hard boundary material in a wide working frequency range in a wide angle and almost without reflection, so that the impedance mismatch problem of the traditional hard boundary material is solved, and the application range of some common hard boundary materials (such as glass, resin, plastic, metal, reinforcing steel bars, concrete and the like) in acoustic engineering such as shock absorption and noise reduction, sonar detection and the like in daily life is widened.
Specifically, when the method is applied to noise reduction, part of walls in a building can be made into a form like an acoustic metamaterial 100 according to the sound frequency to be isolated, and sound absorbing materials are arranged in the walls, so that sound waves transmitted from the outside can be fully absorbed to avoid reflection, and compared with the common cavity walls coated with the sound insulating materials, the method can greatly weaken or eliminate reverberation and scattering of the sound waves, and improve the noise reduction effect.
And when applied to sonar detection, sound waves emitted by the sonar can pass through the acoustic metamaterial 100. Therefore, when the acoustic metamaterial 100 is arranged as a shell, the acoustic tracking device inside the shell can reversely detect the position of the sonar through the received sonar sound wave, so that the unidirectionality of sonar detection is broken, and the development of detection technology is promoted.
In an exemplary embodiment, the plurality of sets of hard boundary material structures includes two sets of first-type hard boundary material structures, one set being disposed on each side of the microstructure; and a set of second type hard boundary material structures disposed between the two sets of first type hard boundary material structures, the second type hard boundary material structures having an effective acoustic velocity less than the effective acoustic velocity of the first type hard boundary material structures. Specifically, as shown in the (B) diagram in fig. 1, the two sides of the microstructure 10 are provided with a class a hard boundary material structure, and a class B hard boundary material structure is arranged between the two groups of class a hard boundary material structures, so that plane symmetry of the microstructure 10 is realized through a simple symmetrical structure, and meanwhile, by adjusting and controlling structural parameters in the class B hard boundary material structure, the effective sound velocity of the class B hard boundary material structure is smaller than that of the class a hard boundary material structure, so as to satisfy the acoustic impedance matching theory under the symmetrical structure.
Further, the first type of hard boundary material structure is formed by a plurality of first hard boundary material units which are arranged at intervals along a preset axisThe method comprises the steps of carrying out a first treatment on the surface of the The second hard boundary material structure is formed by arranging a plurality of second hard boundary material units at intervals along a preset axis. With continued reference to FIG. 1 (b), the class A hard boundary material structure is formed from a plurality of hard boundary material structures having a diameter D A The first hard boundary material units of (a) are arranged at intervals along a preset axis AX, and the B-type hard boundary material structure is formed by a plurality of hard boundary material units with the diameter D B Is formed along the preset axis AX at intervals. The size or the interval distance of the hard boundary material units in various hard boundary material structures can be adjusted, so that the microstructure 10 can better meet the acoustic impedance matching theory.
In other embodiments, the first hard border material element has an arbitrary shape and the second hard border material element has an arbitrary shape. For example, the cross-sectional shape of the two may be circular, elliptical, square, diamond or any shape having an arc, but the shape is not limited thereto, and any shape other than these shapes may be used. The preparation and selection of the hard boundary material units are convenient, the requirements on the shapes of the hard boundary material units are not required, the selection range of the materials is enlarged, and the production and preparation cost is reduced.
Further, as shown in fig. 1 (b), the first hard boundary material unit has a D A A hard boundary cylinder of diameter; the second hard boundary material unit is provided with D B A hard boundary cylinder of diameter; wherein D is A ＜D B Thus, the impedance of the second hard boundary material element is more mismatched to air than the first hard boundary material element, and the acoustic impedance of the second hard boundary material element is greater and more likely to reflect sound waves, which in turn will travel slower through the class B hard boundary material structure. On the other hand, the cylinder is convenient for machining and printing by a 3D printer, and the preparation cost can be further reduced. In addition, the effective sound velocity of the hard boundary material structure can be adjusted only by adjusting the diameter of the cylinder, so that the method is convenient and quick and is beneficial to engineering application.
In an exemplary embodiment, the spacing distances between adjacent hard border material units are all equal. As shown in fig. 1 (b), the spacing distance between two adjacent first hard boundary material units is d, the spacing distance between two adjacent second hard boundary material units is also d, and the spacing distance between two adjacent first hard boundary material units and the second hard boundary material units is also d. In this way, the uneven sound velocity in the corresponding hard boundary material structure caused by the different sparse and dense arrangement of the hard boundary material units can be avoided, and the impedance matching effect of the acoustic metamaterial 100 is further affected.
In an exemplary embodiment, the acoustic metamaterial 100 has a reflectivity of less than or equal to 1% for acoustic waves having a normalized frequency in the range of 0.6 to 0.78 and an incident angle of 0 to 40 °. The acoustic metamaterial has a good reflection weakening or eliminating effect on incident sound waves with normalized frequency of 0.6-0.78 and incident angle of 0-40 degrees, and has a wider application prospect compared with the traditional sound wave anti-reflection device, and the frequency and angle range are greatly widened.
The impedance matching effect of the acoustic metamaterial 100 of the present application will be further illustrated by a set of simulation examples and a set of experimental examples.
Example 1
This embodiment is a simulated embodiment of the acoustic metamaterial 100. The impedance matching effect of the acoustic metamaterial 100 of embodiment 1 will be further described below in conjunction with fig. 2 to 4. It is noted that no loss of acoustic waves in the hard boundary material was introduced at the time of simulation.
Fig. 2 (a) illustrates an incident schematic diagram of example 1, in which an arrow indicates an incident direction (i.e., x-direction) of an acoustic wave. The microstructure 10 is provided with 3 class a thin hard boundary cylinders, 4 class B thick hard boundary cylinders and 3 class a thin hard boundary cylinders at intervals in sequence along the x direction, and the microstructure 10 is arranged in plurality along the y direction.
Fig. 2 (b) illustrates a graph of the acoustic wave transreflection curve when the microstructures 10 are arranged in 2 and 5 layers along the y direction. At this time, the operating frequency of the acoustic metamaterial 100 is normalized frequency fa/c=0.76, which satisfies the impedance matching theory of the acoustic wave, and the corresponding dispersion relation is (k) x a/π-1.51) 2 /0.74+(k y a/π) 2 ＝1.52 2 Wherein f represents the actual operating frequency of the acoustic wave, c represents the speed of the acoustic wave in vacuum, kx representsThe wave vector of the acoustic wave in the x-direction in the acoustic metamaterial 100, ky denotes the wave vector of the acoustic wave in the y-direction in the acoustic metamaterial 100. It can be seen that the transmittance of the acoustic metamaterial 100 at the working frequency is greater than 99% at a wide incidence angle of 0 θ+.ltoreq.60 °, approaching 1, while the reflectance is lower than 1%, approaching 0, and the transmittance and reflectance of the acoustic metamaterial 100 do not vary with the number of layers (N) of the microstructure 10.
Fig. 2 (c) shows a schematic diagram of the reflectance of the acoustic metamaterial 100 as a function of the incident angle and the acoustic frequency, wherein the deeper color indicates weaker reflection, and the deepest place indicates that the reflectance is 0. It can be seen that the acoustic metamaterial 100 can achieve wide-angle anti-reflection effects in the range of 0.5 to 0.8 of normalized frequency when changing frequency.
In addition, two comparative groups of only a type hard boundary material structure and only B type hard boundary material structure were provided in this example, and the results are shown in fig. 3 and 4, respectively.
As shown in fig. 3 (a), the B-type thick hard boundary cylinder in fig. 2 (a) is replaced by a B-type thin hard boundary cylinder. After the sound wave is incident at the same normalized frequency, as shown in (b) and (c) of fig. 3, reflection of the sound wave is obvious, and reflectivity changes with the incident angle of the sound wave and the change of the number of setting layers. In addition, it should be pointed out that, although zero reflection can be achieved at a specific frequency or at a specific angle, this is mainly due to the Fabry-Perot resonance mechanism or the Brewster angle effect, and the impedance mismatch problem is not solved.
As shown in fig. 4 (a), the class a thin hard bounding cylinder in fig. 2 (a) is replaced entirely with a class B thick hard bounding cylinder. After the sound wave is incident at the same normalized working frequency, as shown in the (b) diagram and the (c) diagram in fig. 4, the reflection of the sound wave is more obvious, and the reflectivity can be changed along with the change of the incident angle of the sound wave and the number of setting layers; also, zero reflection can only be achieved at a specific frequency or at a specific angle at this time, and this is mainly due to the Fabry-perot resonance mechanism or the brewster angle effect, and the impedance mismatch problem is not solved yet.
Example 2
This embodiment is an experimental embodiment of the acoustic metamaterial 100. The impedance matching effect of the acoustic metamaterial 100 of embodiment 2 will be further described in conjunction with fig. 5.
As shown in fig. 5, the impedance matching effect of the acoustic metamaterial 100 is further verified by constructing an acoustic experiment platform.
Specifically, a speaker is used as a sound source, and a microphone is used as a receiver. The entire experimental platform was sandwiched by two hard plates, similar to a two-dimensional acoustic waveguide, with a height of 30mm. The sound absorbing sponge is used for eliminating noise effect. Samples were prepared from resin by 3D printing technique, the structural dimensions of the microstructure 10 were a=30 mm, d=3 mm, and the number of cycles in the x-direction was set to 2, and the length in the y-direction was set to 480mm. The situation of different angle incidence is achieved by placing the speaker and microphone in different positions. In this experiment, the measured incidence angles were 10 °, 20 ° and 30 °.
The experimental results are shown by fig. 5, in which the dotted line represents the experimental results and the solid line represents the simulation results of the acoustic metamaterial 100 of example 2. Fig. 5 (a) to (c) show the cases of the acoustic metamaterial 100, the class a material only, and the class B material only in which the reflectivities at 10 °, 20 °, and 30 ° change with frequency, respectively, wherein the circular dots represent the reflectivity experimental data of the acoustic metamaterial 100, the triangular dots represent the reflectivity experimental data at the class a hard boundary material structure only, and the square dots represent the reflectivity experimental data at the class B hard boundary material structure only. It can be seen that the reflectance experimental data of the acoustic metamaterial 100 approaches 0 in the range of 7kHz to 9kHz under different angles of incidence, and is also good in agreement with the simulation curves thereof. Thus, the acoustic metamaterial 100 of the present embodiment can be derived to have the acoustic non-reflection characteristic of a wide frequency and wide angle.
The application also provides an acoustic device.
An acoustic device comprising an acoustic metamaterial as described hereinbefore.
The acoustic device can be prepared from solid materials common in daily life, and can enable incident sound waves to pass through in a wide-angle and almost reflection-free mode in the working frequency range, so that the acoustic device has great application potential in the acoustic engineering fields of vibration reduction, noise reduction, sonar detection and the like.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (10)
1. An acoustic metamaterial based on an impedance matching effect, which is used for weakening or eliminating sound wave reflection, and is characterized by comprising a plurality of microstructures, wherein the microstructures are plane symmetrical structures;
the microstructure is formed by arranging a plurality of groups of hard boundary material structures with sound wave incidence gaps along a preset axis, and the symmetry plane of the microstructure is perpendicular to the preset axis; and, in addition, the method comprises the steps of,
the plurality of sets of hard boundary material structures includes at least two types of hard boundary material structures having different effective sound speeds.
2. The acoustic metamaterial based on impedance matching effects according to claim 1, wherein the plurality of sets of hard boundary material structures comprise:
two groups of first-class hard boundary material structures are respectively arranged on two sides of the microstructure; the method comprises the steps of,
the second type of hard boundary material structures are arranged between the two first type of hard boundary material structures, and the effective sound velocity of the second type of hard boundary material structures is smaller than that of the first type of hard boundary material structures.
3. An acoustic metamaterial based on impedance matching effects as claimed in claim 2, wherein,
the first hard boundary material structure is formed by arranging a plurality of first hard boundary material units at intervals along the preset axis;
the second hard boundary material structure is formed by arranging a plurality of second hard boundary material units at intervals along the preset axis.
4. An acoustic metamaterial based on the impedance matching effect according to claim 3, wherein the cross-sectional shape of the first hard border material unit is circular, elliptical, square or diamond, and the cross-sectional shape of the second hard border material unit is circular, elliptical, square or diamond.
5. An acoustic metamaterial based on impedance matching effects as claimed in claim 3, wherein,
the first hard border material unit is a hard border cylinder with a first diameter;
the second hard border material unit is a hard border cylinder with a second diameter;
wherein the first diameter is smaller than the second diameter.
6. An acoustic metamaterial based on impedance matching according to any of claims 3 to 5, wherein the spacing distance between adjacent hard boundary material units is equal.
7. The acoustic metamaterial based on impedance matching effects according to any one of claims 1 to 5, wherein the acoustic metamaterial is formed from the plurality of microstructures arranged in an array.
8. The acoustic metamaterial based on impedance matching effects according to any one of claims 1 to 5, wherein the acoustic metamaterial has a reflectivity of less than or equal to 1% for acoustic waves with normalized frequencies in the range of 0.6 to 0.78 and with incidence angles of 0 to 40 °.
9. The acoustic metamaterial based on impedance matching effects according to any one of claims 1 to 5, wherein the hard boundary material is at least one of plastic, glass, resin, metal, steel bar, and concrete.
10. An acoustic device comprising an acoustic metamaterial based on impedance matching effects as claimed in any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010365374.9A CN111524496B (en) | 2020-04-30 | 2020-04-30 | Acoustic metamaterial and acoustic device based on impedance matching effect |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010365374.9A CN111524496B (en) | 2020-04-30 | 2020-04-30 | Acoustic metamaterial and acoustic device based on impedance matching effect |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111524496A CN111524496A (en) | 2020-08-11 |
| CN111524496B true CN111524496B (en) | 2023-09-01 |
Family
ID=71912216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010365374.9A Active CN111524496B (en) | 2020-04-30 | 2020-04-30 | Acoustic metamaterial and acoustic device based on impedance matching effect |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111524496B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016173502A1 (en) * | 2015-04-28 | 2016-11-03 | The Hong Kong University Of Science And Technology | Degenerate resonators using elastic metamaterials with independent monopole and dipole resonant structures |
| CN106650179A (en) * | 2017-01-23 | 2017-05-10 | 东南大学 | Method of designing Acoustic Metamaterials based on CMA-ES optimization algorithm |
| CN109541026A (en) * | 2018-12-07 | 2019-03-29 | 中国特种设备检测研究院 | A kind of the non-linear ultrasonic detection system and detection method of reflective contact metal croop property |
| CN110277083A (en) * | 2018-03-16 | 2019-09-24 | 北京理工大学 | A kind of low frequency absorption Meta Materials |
-
2020
- 2020-04-30 CN CN202010365374.9A patent/CN111524496B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016173502A1 (en) * | 2015-04-28 | 2016-11-03 | The Hong Kong University Of Science And Technology | Degenerate resonators using elastic metamaterials with independent monopole and dipole resonant structures |
| CN106650179A (en) * | 2017-01-23 | 2017-05-10 | 东南大学 | Method of designing Acoustic Metamaterials based on CMA-ES optimization algorithm |
| CN110277083A (en) * | 2018-03-16 | 2019-09-24 | 北京理工大学 | A kind of low frequency absorption Meta Materials |
| CN109541026A (en) * | 2018-12-07 | 2019-03-29 | 中国特种设备检测研究院 | A kind of the non-linear ultrasonic detection system and detection method of reflective contact metal croop property |
Non-Patent Citations (1)
| Title |
|---|
| Chenkai Liu等.《PHYSICAL REVIEW MATERIALS》.2018,045201-1至045201-8. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111524496A (en) | 2020-08-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Li et al. | A sound absorbing metasurface with coupled resonators | |
| US11043199B2 (en) | Sparse acoustic absorber | |
| CN105750181A (en) | Device for generating acoustic vortex field by utilizing acoustic metamaterial | |
| US11557271B2 (en) | Degenerative sound isolation device | |
| CN109979426B (en) | Acousto-electric independent modulation coding metamaterial and preparation method and modulation method thereof | |
| Naify et al. | Experimental realization of a variable index transmission line metamaterial as an acoustic leaky-wave antenna | |
| US10714070B1 (en) | Sound isolation device | |
| JP6940556B2 (en) | Invisible noise barrier | |
| CN110738979B (en) | Tunable ultrasonic metamaterial and waveguide mode converter comprising same | |
| Mak et al. | Going beyond the causal limit in acoustic absorption | |
| CN104752840A (en) | Terahertz broadband random surface | |
| CN111524496B (en) | Acoustic metamaterial and acoustic device based on impedance matching effect | |
| Liu et al. | Wide-angle broadband nonreflecting acoustic metamaterial fence | |
| CN104751840B (en) | A kind of acoustical material that ultra wide band sound wave can be made to focus | |
| US4303144A (en) | Apparatus for the retroreflection of sound | |
| JPS6014359B2 (en) | Sound absorbing panels and sound absorbing structures | |
| US11854522B2 (en) | Sound absorbing structure having one or more acoustic scatterers attached to a transparent panel | |
| CN103945302A (en) | Active single-direction acoustic propagation device and method for realizing single-direction acoustic propagation | |
| US11776522B2 (en) | Sound isolating wall assembly having at least one acoustic scatterer | |
| WO2012155475A1 (en) | Electromagnetic wave beam splitter | |
| CN112199899A (en) | Single-source generation method and generation device for orbital angular momentum in two-dimensional fluctuation system | |
| CN110880311A (en) | Underwater sub-wavelength space coiled acoustic metamaterial | |
| EP3779080A1 (en) | Sound absorption device and method of manufacturing the same | |
| Li et al. | Helmholtz-Structured Two-Dimensional Super-Diffraction Meta-Lens | |
| Naify et al. | Evaluation of an acoustic metamaterial leaky-wave antenna |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |