CN111524497A - Fractal structure acoustic metamaterial based on electrorheological fluid - Google Patents
Fractal structure acoustic metamaterial based on electrorheological fluid Download PDFInfo
- Publication number
- CN111524497A CN111524497A CN202010315100.9A CN202010315100A CN111524497A CN 111524497 A CN111524497 A CN 111524497A CN 202010315100 A CN202010315100 A CN 202010315100A CN 111524497 A CN111524497 A CN 111524497A
- Authority
- CN
- China
- Prior art keywords
- flow channel
- acoustic metamaterial
- electrorheological fluid
- fractal
- sound
- 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.)
- Granted
Links
Images
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
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
Abstract
A fractal structure acoustic metamaterial based on electrorheological fluid is characterized in that a fractal structure acoustic metamaterial base body (1) is of a cuboid structure and is formed by nesting two parts with concave and convex horizontal sections, and a cavity between the concave part and the convex part forms a flow channel (2); the horizontal section of the flow channel (2) is in a Hilbert fractal curve shape; electrorheological fluid (3) is filled in the flow channel (2), metal electrodes (4) are attached to two side walls, and outlet terminals of the metal electrodes are connected with a direct current power supply (10). When sound waves are transmitted to the sound wave incident surface (6), due to the characteristics of strong reflection and equivalent high refractive index of the fractal structure acoustic metamaterial (11) based on the electrorheological fluid, the sound pressure of a target area under specific frequency is reduced. And adjusting the voltage of the direct current power supply (10) to shift the sound insulation frequency of the acoustic metamaterial (11) based on the electrorheological fluid, so as to adjust and control the sound insulation frequency of the acoustic metamaterial.
Description
Technical Field
The invention relates to a fractal structure acoustic metamaterial.
Background
With the acceleration of urbanization process, noise seriously harms the quality of life and physical and psychological health of residents, and becomes one of three environmental pollutions. Complaints of traffic and large electrical equipment noise account for a high percentage. Both traffic noise and power equipment operation noise have remarkable low-frequency line spectrum characteristics, and low-frequency components below 1000Hz are prominent. Relevant researches show that the incidence rate of speech frequency hearing impairment is close to 14.37% even damage to the nervous system and visceral organs when the hearing aid works for a long time or lives in a low-frequency high-noise environment.
Corresponding vibration and noise reduction measures have been adopted in the design process of traffic and electric power facilities, for example, sound insulation and absorption materials are attached to the wall in a substation room; the sound insulation barriers are arranged on two sides of the track, and the noise reduction purpose is achieved by changing the noise size and the transmission direction through absorption, reflection and refraction of the barriers. The traditional material has obvious noise reduction effect on high-frequency noise, but has little effect on low-frequency noise. In 2000, acoustic metamaterials based on the local resonance principle were introduced. The material breaks through the traditional sound quality law, and the realization of the light and thin low-frequency vibration and noise reduction material becomes possible. The acoustic metamaterial is based on a resonance principle, is a composite structure formed by specially designed artificial microstructure units, and has the physical characteristics of negative equivalent mass density, negative equivalent bulk modulus and the like exceeding those of natural materials. The acoustic metamaterial has the characteristic of sub-wavelength sound wave control, namely, the sound wave control which is two orders of magnitude larger than the size of the metamaterial unit can be realized by adopting the smaller size of the metamaterial unit. The acoustic metamaterial has one or more band gaps in a low-frequency band, and noise near the frequency of the band gap can be effectively blocked. The characteristic provides a new theoretical support for solving the problem of low-frequency noise treatment.
The acoustic metamaterial has a remarkable advantage in the aspect of low-frequency noise regulation and suppression, but the acoustic metamaterial has a problem when being used for noise reduction of facilities such as electric equipment and rail transit. The main reason is that once the metamaterial structure and dimension are determined, the noise reduction frequency is determined immediately and cannot be adjusted. Machining errors and other factors easily cause deviation between actual materials and design results; in addition, real environment noise often has time-varying characteristics, and the material of fixed noise reduction frequency is difficult to make dynamic response to the noise that changes, and environmental suitability is relatively poor.
Disclosure of Invention
The invention aims to overcome the defects of the existing acoustic metamaterial, and provides a fractal structure acoustic metamaterial based on electrorheological fluid by combining the electrorheological fluid with the fractal structure acoustic metamaterial. The characteristic that the complex shear modulus of the electrorheological fluid changes along with the intensity of an external electric field is utilized, the sound field is regulated and controlled through the electric field, the defect that the band gap of the acoustic metamaterial is fixed and unchanged is overcome, and the adjustability of sound insulation frequency is realized.
The fractal structure acoustic metamaterial based on the electrorheological fluid comprises a fractal structure acoustic metamaterial base body, a flow channel, a metal electrode, the electrorheological fluid and a sealing film.
The fractal structure acoustic metamaterial base body is of a cuboid structure and is formed by nesting two parts with concave and convex horizontal sections, and a cavity between the two parts forms a flow channel. The shape of the horizontal section of the flow channel is a Hilbert fractal curve. The flow channel has two ports: the flow channel inlet and the flow channel outlet are communicated with the outside. The acoustic wave incident surface and the acoustic wave emergent surface are respectively positioned on two parallel and opposite side surfaces of the fractal structure acoustic metamaterial base body, the plane where the flow channel inlet is positioned is parallel to the acoustic wave incident surface, the plane where the flow channel outlet is positioned is parallel to the acoustic wave emergent surface, and therefore the flow channel inlet is parallel to the flow channel outlet. The sound wave incident surface and the sound wave emergent surface are defined as vertical planes.
The fractal structure acoustic metamaterial base body is made of epoxy resin materials.
And metal electrodes are attached to two side walls of the flow channel, a positive electrode is arranged on one side, and a negative electrode is arranged on the other side. The positive electrode outlet terminal and the negative electrode outlet terminal are positioned on the sound wave incident surface or the sound wave emergent surface. The positive electrode outlet terminal is connected with the positive electrode of the direct current power supply through a lead, and the negative electrode outlet terminal is connected with the negative electrode of the direct current power supply through a lead.
Electrorheological fluid is filled in the flow channel.
The sealing film is a plastic film and wraps the surface of the fractal structure acoustic metamaterial to prevent the electrorheological fluid filled in the flow channel from flowing out.
The electrorheological fluid is insulating oil added with micro-particles or nano-particles, and the dielectric constant of the micro-particles or the nano-particles is far greater than that of the insulating oil. The complex shear modulus of an electrorheological fluid is related to the electric field intensity applied to the electrorheological fluid and is expressed as:
G＝G′+iG″ (1)
wherein G 'is the real part of the complex shear modulus, and G' is the imaginary part of the complex shear modulus. G 'and G' are related to the electric field strength.
The external electric field intensity of the electrorheological fluid is the ratio of the output voltage of the direct-current power supply to the width of the flow channel. The width of the flow channel and the external electric field intensity of the electrorheological fluid are closely related to the sound insulation frequency, and the width of the flow channel and the external electric field intensity of the electrorheological fluid are designed according to the required sound insulation frequency.
The working process of the invention is as follows: the sound waves are transmitted to the fractal structure acoustic metamaterial base body, and near the band gap frequency, the sound waves are refracted and reflected for multiple times in the fractal structure acoustic metamaterial base body, and the sound energy is consumed, so that the sound pressure of a target noise reduction area is greatly attenuated. By means of external power supply voltage, the external electric field intensity of the electrorheological fluid in the flow channel is changed, the compound shear modulus of the electrorheological fluid is changed accordingly, the sound insulation frequency of the electrorheological fluid acoustic metamaterial is deviated, and the sound insulation frequency can be adjusted.
The invention organically combines the advantages of the electrorheological fluid and the acoustic metamaterial and has the advantage of flexible and adjustable sound insulation frequency.
Drawings
FIG. 1 is a schematic diagram of an electrorheological fluid-based fractal structure acoustic metamaterial according to the present invention;
FIG. 2 is a cross-sectional view of a fractal structure acoustic metamaterial matrix in the horizontal direction;
FIG. 3 is a cross-sectional view of an acoustic metamaterial with a fractal structure based on electro-rheological fluid according to the present invention;
FIG. 4 is a graph of acoustic loss of fractal-bonded hook acoustic metamaterial based on electrorheological fluid as a function of frequency.
In the figure: the acoustic metamaterial comprises a fractal structure acoustic metamaterial base body 1, a flow channel 2, electrorheological fluid 3, metal electrodes 4, a sealing film 5, a sound wave incident surface 6, a sound wave emergent surface 7, a positive electrode wire outlet terminal 8, a negative electrode wire outlet terminal 9, a direct current power supply 10 and a fractal structure acoustic metamaterial 11 based on the electrorheological fluid.
Detailed Description
The invention is further described below with reference to the accompanying drawings and the detailed description.
As shown in FIG. 1, the fractal structure acoustic metamaterial 11 based on the electrorheological fluid comprises a fractal structure acoustic metamaterial base body 1, a flow channel 2, the electrorheological fluid 3, a metal electrode 4 and a sealing film 5.
As shown in fig. 2, a fractal structure acoustic metamaterial substrate 1 according to an embodiment of the present invention is a rectangular parallelepiped structure, and is formed by nesting two parts, a horizontal cross section of which is concave and convex, and a cavity between the concave part and the convex part forms a flow channel 2. The horizontal section of the flow channel 2 is in a Hilbert fractal curve shape. The flow channel width of this example is 4mm and the horizontal cross-sectional dimension is 60 mm.
As shown in fig. 3, the flow channel 2 has two ports: the flow channel inlet and the flow channel outlet are communicated with the outside. The sound wave incident surface 6 and the sound wave emergent surface 7 are respectively positioned on two parallel and opposite side surfaces of the fractal structure acoustic metamaterial base body, the plane where the flow channel inlet is positioned is parallel to the sound wave incident surface 6, and the plane where the flow channel outlet is positioned is parallel to the sound wave emergent surface 7, so that the flow channel inlet is parallel to the flow channel outlet.
The fractal structure acoustic metamaterial base body 1 is made of epoxy resin materials.
And metal electrodes 4 are attached to two side walls of the flow channel 2, one side of the flow channel is a positive electrode, and the other side of the flow channel is a negative electrode. The positive electrode outlet terminal 8 and the negative electrode outlet terminal 9 are located on the sound wave incident surface or the sound wave emergent surface. The positive electrode outlet terminal 8 is connected with the positive electrode of a direct current power supply 10 through a lead, and the negative electrode appearance terminal 9 is connected with the negative electrode of the direct current power supply 10 through a lead. The voltage of the direct current power supply is adjustable. The variation range of the external electric field intensity of the electrorheological fluid is as follows: 1kV/mm-3 kV/mm.
The flow channel 2 is filled with electrorheological fluid 3. The electrorheological fluid 3 is insulating oil added with micron or nanometer particles with high dielectric property. The sealing film 5 is a plastic film and wraps the surface of the fractal structure acoustic metamaterial base body 1 to prevent the electrorheological fluid 3 filled in the flow channel 2 from flowing out.
The working process of the invention is as follows:
the sound wave is transmitted to the fractal structure acoustic metamaterial base body 1, and near the band gap frequency, the sound wave is refracted and reflected for many times in the fractal structure acoustic metamaterial 11, and the sound energy is consumed, so that the sound pressure of the target noise reduction area is greatly attenuated. By adjusting the voltage of the external direct current power supply 10, the external electric field intensity of the electrorheological fluid 3 in the flow channel 2 is changed, the complex shear modulus of the electrorheological fluid 3 is changed therewith, and the sound insulation frequency of the fractal structure acoustic metamaterial 11 based on the electrorheological fluid 3 is deviated. The frequency domain analysis results in the variation of acoustic transmission loss with frequency as shown in fig. 4. As shown in fig. 4, after the electrorheological fluid 3 is injected into the flow channel 2, the overall sound transmission loss of the fractal structure acoustic metamaterial 11 based on the electrorheological fluid is increased no matter the intensity of the applied electric field, and the peak value of the sound transmission loss moves to a low frequency. When the intensity of the electric field applied to the electrorheological fluid is small, the sound transmission loss is gradually increased along with the increase of the frequency. As the electric field strength increases, the sound transmission loss begins to peak and valley with the frequency. When the intensity of the applied electric field is increased from 1kV/mm to 3kV/mm, the frequency of the first peak of the sound transmission loss curve is gradually increased. Therefore, the sound insulation frequency of the acoustic metamaterial can be regulated and controlled by regulating the external electric field intensity of the electrorheological fluid.
Claims (5)
1. A fractal structure acoustic metamaterial based on electrorheological fluid is characterized in that: the acoustic metamaterial comprises a fractal structure acoustic metamaterial base body (1), a flow channel (2), electrorheological fluid (3), a metal electrode (4) and a sealing film (5); the fractal structure acoustic metamaterial base body (1) is of a cuboid structure and is formed by nesting two parts with concave and convex horizontal sections, and a cavity between the two parts forms a flow channel (2); the horizontal section of the flow channel (2) is in a Hilbert fractal curve shape; electrorheological fluid (3) is filled in the flow channel (2); metal electrodes (4) are attached to two side walls of the flow channel (2), one side is a positive electrode, and the other side is a negative electrode; the outlet terminals of the positive electrode and the negative electrode are connected with a direct current power supply (10); the sealing film (5) is a plastic film and wraps the surface of the fractal structure acoustic metamaterial base body (1).
2. The electrorheological-fluid-based fractal-structure acoustic metamaterial according to claim 1, wherein: the flow channel (2) is provided with two ports: the flow channel inlet and the flow channel outlet are communicated with the outside; the acoustic wave incident surface (6) and the acoustic wave emergent surface (7) are respectively positioned on two parallel and opposite side surfaces of the fractal structure acoustic metamaterial base body (1), the plane where the flow channel inlet is positioned is parallel to the acoustic wave incident surface (6), the plane where the flow channel outlet is positioned is parallel to the acoustic wave emergent surface (7), and the flow channel inlet is parallel to the flow channel outlet; the positive electrode outlet terminal and the negative electrode outlet terminal are positioned on the sound wave incident surface (6) or the sound wave emergent surface (7).
3. The electrorheological-fluid-based fractal-structure acoustic metamaterial according to claim 1, wherein: the electrorheological fluid (3) is insulating oil added with micro-particles or nano-particles, and the dielectric constant of the micro-particles or the nano-particles is greater than that of the insulating oil.
4. The electrorheological-fluid-based fractal-structure acoustic metamaterial according to claim 1, wherein: the fractal structure acoustic metamaterial base body (1) is made of epoxy resin materials.
5. The electrorheological-fluid-based fractal-structure acoustic metamaterial according to claim 1, wherein: the sound wave is transmitted to the fractal structure acoustic metamaterial base body (1), and near the band gap frequency, the sound wave is refracted and reflected in the fractal structure acoustic metamaterial (11), and the sound energy is consumed, so that the sound pressure of a target noise reduction area is greatly attenuated; the external electric field intensity of the electrorheological fluid (3) in the flow channel (2) is changed by adjusting the voltage of an external direct current power supply (10), the complex shear modulus of the electrorheological fluid (3) is changed therewith, the sound insulation frequency of the fractal structure acoustic metamaterial (11) based on the electrorheological fluid (3) is shifted, and the change of sound transmission loss along with the frequency is obtained through frequency domain analysis; the sound insulation frequency of the acoustic metamaterial is regulated and controlled by adjusting the external electric field intensity of the electrorheological fluid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010315100.9A CN111524497B (en) | 2020-04-21 | 2020-04-21 | Fractal structure acoustic metamaterial based on electrorheological fluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010315100.9A CN111524497B (en) | 2020-04-21 | 2020-04-21 | Fractal structure acoustic metamaterial based on electrorheological fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111524497A true CN111524497A (en) | 2020-08-11 |
| CN111524497B CN111524497B (en) | 2023-10-20 |
Family
ID=71903883
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010315100.9A Active CN111524497B (en) | 2020-04-21 | 2020-04-21 | Fractal structure acoustic metamaterial based on electrorheological fluid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111524497B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112282089A (en) * | 2020-10-20 | 2021-01-29 | 黄飞雁 | Rheological state acoustic celotex board based on classic absorption |
| US11609421B2 (en) | 2021-04-12 | 2023-03-21 | Toyota Motor Engineering & Manufacturing North America, Inc. | Fluid filled active metasurface |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4923057A (en) * | 1988-09-20 | 1990-05-08 | Lord Corporation | Electrorheological fluid composite structures |
| TW543732U (en) * | 2002-06-14 | 2003-07-21 | Tsung-Neng Wu | Improved electrorheological fluid shock absorber structure |
| CN1434541A (en) * | 2002-01-23 | 2003-08-06 | 西北工业大学 | Electrorheological fluid controlled intelligent microwave attenuator |
| CN1540181A (en) * | 2003-10-29 | 2004-10-27 | 北京工业大学 | Bielectrode composite structural piece in use for current liquescent |
| CN105044158A (en) * | 2015-08-18 | 2015-11-11 | 西北工业大学 | Electro-rheological characteristic test device and electro-rheological characteristic test method of flammable and combustible liquid |
| CN106328115A (en) * | 2016-08-22 | 2017-01-11 | 东南大学 | Low-frequency sound-insulation artificial material based on fractal structure |
| CN109148123A (en) * | 2018-08-30 | 2019-01-04 | 中国科学院电工研究所 | For the acoustic metamaterial barrier system of transformer noise spatial characteristics |
| US20190139529A1 (en) * | 2015-10-30 | 2019-05-09 | Massachusetts Institute Of Technology | Subwavelength Acoustic Metamaterial With Tunable Acoustic Absorption |
| CN110055125A (en) * | 2019-05-31 | 2019-07-26 | 青岛科技大学 | A kind of hud typed composite material by electric current of anisotropic TS-1 molecular sieve/TiOx nano becomes liquid and preparation method thereof |
-
2020
- 2020-04-21 CN CN202010315100.9A patent/CN111524497B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4923057A (en) * | 1988-09-20 | 1990-05-08 | Lord Corporation | Electrorheological fluid composite structures |
| CN1434541A (en) * | 2002-01-23 | 2003-08-06 | 西北工业大学 | Electrorheological fluid controlled intelligent microwave attenuator |
| TW543732U (en) * | 2002-06-14 | 2003-07-21 | Tsung-Neng Wu | Improved electrorheological fluid shock absorber structure |
| CN1540181A (en) * | 2003-10-29 | 2004-10-27 | 北京工业大学 | Bielectrode composite structural piece in use for current liquescent |
| CN105044158A (en) * | 2015-08-18 | 2015-11-11 | 西北工业大学 | Electro-rheological characteristic test device and electro-rheological characteristic test method of flammable and combustible liquid |
| US20190139529A1 (en) * | 2015-10-30 | 2019-05-09 | Massachusetts Institute Of Technology | Subwavelength Acoustic Metamaterial With Tunable Acoustic Absorption |
| CN106328115A (en) * | 2016-08-22 | 2017-01-11 | 东南大学 | Low-frequency sound-insulation artificial material based on fractal structure |
| CN109148123A (en) * | 2018-08-30 | 2019-01-04 | 中国科学院电工研究所 | For the acoustic metamaterial barrier system of transformer noise spatial characteristics |
| CN110055125A (en) * | 2019-05-31 | 2019-07-26 | 青岛科技大学 | A kind of hud typed composite material by electric current of anisotropic TS-1 molecular sieve/TiOx nano becomes liquid and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 夏百战;刘亭亭;郑圣洁;于德介;: "基于Hilbert分形的亚波长空间盘绕型声学超材料", no. 06, pages 79 - 85 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112282089A (en) * | 2020-10-20 | 2021-01-29 | 黄飞雁 | Rheological state acoustic celotex board based on classic absorption |
| CN112282089B (en) * | 2020-10-20 | 2022-03-25 | 广西鸿昊新材料有限公司 | Rheological state acoustic celotex board based on classic absorption |
| US11609421B2 (en) | 2021-04-12 | 2023-03-21 | Toyota Motor Engineering & Manufacturing North America, Inc. | Fluid filled active metasurface |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111524497B (en) | 2023-10-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111524497A (en) | Fractal structure acoustic metamaterial based on electrorheological fluid | |
| Fu et al. | A review on polymer-based materials for underwater sound absorption | |
| Goffaux et al. | Measurements and calculations of the sound attenuation by a phononic band gap structure suitable for an insulating partition application | |
| CN110390926B (en) | Adjustable piezoelectric phononic crystal for inhibiting broadband elastic wave propagation | |
| CN112779998B (en) | Full-band super-structure sound absorber | |
| CN111925586B (en) | Vibrating diaphragm of sound production device, preparation method of vibrating diaphragm and sound production device | |
| CN102354493A (en) | Controllable underwater acoustic board | |
| Jeon et al. | Nonlinear acoustic metamaterial for efficient frequency down-conversion | |
| Sampaio et al. | Membrane smart metamaterials for unidirectional wave propagation problems | |
| CN111402852A (en) | Low frequency sound absorption and soft boundary effect for frequency discrete active panels | |
| CN111739502A (en) | Underwater sound absorption metamaterial with damping lining hexagonal honeycomb perforated plate | |
| CN116312437A (en) | Low-frequency broadband sound absorption and noise reduction structure | |
| CN111916040B (en) | Membrane type acoustic metamaterial sound absorption and insulation device with perforated plates | |
| Malléjac et al. | Doping of a plate-type acoustic metamaterial | |
| Yuan et al. | A novel circular plate acoustic energy harvester for urban railway noise | |
| CN212542153U (en) | Sound absorption and insulation integrated device for suppressing low-frequency noise of power transformer | |
| CN114913839A (en) | Frequency-adjustable electrorheological fluid noise reduction device | |
| CN109389965B (en) | Broadband sound wave absorber and construction method thereof | |
| CN112331171A (en) | Ultra-light low-frequency noise reduction film metamaterial | |
| Liu et al. | Miniaturized spiral metamaterial array for a ventilated broadband acoustic absorber | |
| Umnova et al. | Nonlinear behaviour of lossy acoustic black holes | |
| Pavan et al. | Effect of micro-slit entries on the sound absorption and size of a labyrinthine acoustic metamaterial | |
| CN214688329U (en) | Broadband noise reduction composite sandwich plate | |
| CN217361121U (en) | Nonlinear structural unit and low-frequency broadband noise reduction metamaterial structure | |
| CN109599087B (en) | Mixed sound absorption and insulation device for multi-frequency band noise reduction of transformer |
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 |