CN212426813U - Compound sound barrier structure based on phononic crystal - Google Patents
Compound sound barrier structure based on phononic crystal Download PDFInfo
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- CN212426813U CN212426813U CN202020191551.1U CN202020191551U CN212426813U CN 212426813 U CN212426813 U CN 212426813U CN 202020191551 U CN202020191551 U CN 202020191551U CN 212426813 U CN212426813 U CN 212426813U
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Abstract
The utility model belongs to the control field of making an uproar falls in the rail transit damping, its aim at provides a compound sound protective screen structure based on phononic crystal, its characterized in that: the sound barrier structure comprises a sound barrier unit upper part and a sound barrier unit lower part, wherein the sound barrier unit upper part comprises two plates which are arranged in a V shape, so that the sound barrier unit upper part and the sound barrier unit lower part are integrally combined into a Y shape, the barrier unit upper part comprises foamed aluminum, and the sound barrier unit lower part comprises an air layer. The utility model has the advantages of being simple in whole structure, making conveniently, dismantle simple to operate, to the wheel rail vibration and the noise that arouse because railway circuit is not in the same direction as have good damping noise reduction effect, lower to operational environment's requirement, can be used for reducing the noise that the railway train wheel produced, improve the noise, the vibration characteristic of railway train wheel, reduce the influence to surrounding environment, improve workman operational environment etc..
Description
Technical Field
The utility model belongs to the technical field of the equipment of making an uproar falls, concretely relates to compound sound barrier structure based on phononic crystal.
Background
With the rapid development of rail transit in China, the speed of a train is increased for several times, huge noise is generated, the exposure duration of the noise is long, and the daily life of residents along the line is seriously interfered. Highways and subway overhead lines in cities are increasingly dense, and traffic noise has increasingly prominent influence on the beautiful life of people.
In order to reduce the interference of traffic noise to residents along the line, the sound barrier has irreplaceable advantages and is one of the effective measures for preventing noise pollution at present. Therefore, the sound barrier is widely used, but the design of the sound barrier is mainly used for sound insulation, cannot solve the diffraction sound of noise, has limited effect of reducing the noise, and the sound barriers in various places are all uniform and cannot be adjusted according to specific environmental noise, so that the expected effect cannot be achieved.
The phononic crystal is a functional material which is composed of two or more elastic media and has a periodic structure and elastic wave band gap characteristics. In the phononic crystal, materials with different densities and elastic constants are periodically compounded together according to a structure, the materials which are not communicated with each other are called scatterers, and the materials which are communicated into a whole are used as a matrix. When elastic waves propagate in the phononic crystal, a special dispersion relation is formed under the action of an internal periodic structure, and the frequency between dispersion relation curves is called as the elastic wave propagation of a band gap frequency range and is restrained. A novel noise reduction structure can be designed by utilizing the property of the band gap, so that the phononic crystal has wide application prospect in the field of noise reduction.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to solve the relatively poor problem of present sound barrier noise reduction performance, and then provide a compound sound barrier structure based on phononic crystal, this compound sound barrier adopts measures such as local resonance type phononic crystal and one-dimensional phononic crystal quasi-periodic structure.
The utility model provides a novel sound barrier structure based on phononic crystal, its characterized in that: the sound barrier unit comprises an upper sound barrier unit part and a lower sound barrier unit part, wherein the upper sound barrier unit part comprises two plates which are arranged in a V shape, so that the upper sound barrier unit part and the lower sound barrier unit part are integrally combined into a Y shape, the upper sound barrier unit part comprises foamed aluminum, and the lower sound barrier unit part comprises an air layer.
Further, it is characterized in that: each plate on the upper part of the sound barrier unit comprises a metal shell, and a damping material and a cellular structure which are arranged in the metal shell, wherein the cellular structure comprises the foamed aluminum; an opening is formed in the metal shell and faces the direction of a noise source, a cellular structure is connected to each opening, and damping materials are filled outside the cellular structures in the metal shell.
Further, it is characterized in that: the cellular structure is a round cake shape and comprises three layers of spherical annular foamed aluminum and cellular cavities positioned between adjacent foamed aluminum layers and in the innermost foamed aluminum layer, wherein each layer of foamed aluminum is provided with a notch, and the notches and the openings are coaxially arranged.
Further, it is characterized in that: the opening height of the gap of the three layers of spherical annular foamed aluminum is reduced along with the reduction of the radius.
Further, it is characterized in that: the ratio of the radius of the spherical ring-shaped foamed aluminum to the height of the gap is 1:1.5 from inside to outside.
Further, it is characterized in that: the metal shells of the two plates are integrally formed.
Further, it is characterized in that: the lower part of the sound barrier of the lower unit of the sound barrier unit comprises an open-pore metal plate, air layers and porous sound absorption material layers which are alternately distributed, and a solid metal plate, wherein the open-pore metal plate is arranged on one side of a noise source, and the solid metal plate is arranged on one side far away from the noise source.
Further, it is characterized in that: the thickness of the air layer varies periodically.
Further, it is characterized in that: the thickness of the air layer satisfies the following formula, dA(i)＝dA(1+ α cos2 π δ (i)/n), where δ (i) ═ 0, ± 1, ± 2ADenotes the initial thickness, dA(i) Expressing the thickness of the ith air layer, a constant n as a modulation parameter, a variable delta for changing the modulation intensity, and a variable alpha for influencing the composition ratio of the structure。
Further, it is characterized in that: the sound barrier structure further comprises a bottom support formed by trapezoidal concrete, and the lower unit of the sound barrier is connected with the trapezoidal concrete through bolts and spiral sleeve metal base plates.
The utility model discloses a compound sound barrier, wherein, the noise of high-frequency in can absorbing by the porous sound absorbing material among the one-dimensional phonon crystal structure, and local resonance type phonon crystal can absorb low frequency noise in the ordinary steel sheet of unilateral open-ended has elastic wave forbidden band characteristic simultaneously, can the transmission of effective control noise, strides porous sound absorbing material cycle for a long time and arranges, can more effective absorbed noise.
1) The utility model discloses a by angle steel and bolted connection between superstructure and the substructure, stable in structure easily field installation. The lower structure of the sound barrier and the concrete are fixed through angle steel and bolts, so that the sound barrier has strong transverse stability, and all structures are cold-resistant, heat-resistant and corrosion-resistant.
2) The utility model has the advantages of material economy, simple installation, good and reliable stability of durability, can reach the efficiency of making an uproar that falls in the sound absorption for a long time.
Drawings
FIG. 1 is a side view of a composite sound barrier construction;
FIG. 2 is a schematic view of the composite sound barrier;
FIG. 3 is a front view of a composite sound barrier construction;
FIG. 4 is a front view of a phononic crystal unit cell structure;
FIG. 5 is a side view of a phononic crystal cell structure;
fig. 6 is a schematic diagram of a quasi-periodic structure in the composite sound barrier.
The figures are labeled as follows: 1-damping material, 2-metal shell, 3-cavity, 4-foamed aluminum, 5-opening, 6-air layer, 7-porous sound absorption material, 8-open-cell metal plate, 9-solid metal plate, 10-bolt, 11-nut, 12-metal backing plate, 13-angle steel, 14-concrete base, 15-sound inlet hole and 16-spiral sleeve.
Detailed Description
In order to make the technical solutions and advantages of the present invention clearer, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
The present example relates to a composite sound barrier unit using a local resonance type phononic crystal, a one-dimensional phononic crystal quasi-periodic structure and various sound absorption principles, which comprises foamed aluminum and an air layer, wherein the two materials have different acoustic impedances. The sound barrier structure comprises an upper part of a sound barrier unit, a lower part of the sound barrier unit and a bottom support of the sound barrier unit, and all the parts are connected and fixed through a mechanical structure. Preferably, angle steel 13, bolts 10 and nuts 11 are used to connect and fix the upper part of the sound barrier unit and the lower part of the sound barrier unit and the bottom support of the sound barrier unit (only the connection structure between the lower part of the sound barrier unit and the bottom support of the sound barrier unit is specifically shown in fig. 1).
Preferably, the overall height of the sound barrier is preferably 2-4m, the height of the upper part of the sound barrier unit is about 1/3 of the lower part of the sound barrier unit, and the height of the bottom support of the sound barrier unit is about 1/3 of the upper structure of the sound barrier unit. Wherein the sound barrier unit upper part comprises two plates arranged in a V-shape, and preferably each plate intersects the vertical normal at 45 °, so that the sound barrier unit upper part and the sound barrier unit lower part are integrally formed into a Y-shape.
Preferably, each plate on the upper part of the sound barrier unit comprises a metal shell 2, and a damping material 1 and a cellular structure which are arranged in the metal shell 2, wherein an opening 5 is arranged on the metal shell 2, the opening faces the direction of a noise source, one cellular structure is connected at each opening 5, and the damping material is filled outside the cellular structure in the metal shell. Wherein the metal shells 2 of the two plates are integrally formed or are connected in two parts, preferably the metal shell 2 of each plate is 100mm thick and 400mm long.
The cellular structure is shown in fig. 4 and 5, and comprises three layers of spherical annular foamed aluminum 4 and cellular cavities 3 positioned between adjacent foamed aluminum 4 layers and in the innermost foamed aluminum 4, the whole cellular structure is similar to a round cake shape, the thickness of the cellular structure is the opening width, two sides of the round cake-shaped structure are thin aluminum planes (not shown in the figure), the three layers of foamed aluminum and the thin aluminum planes are fixed, each layer of foamed aluminum 4 is provided with a notch 41, and the notches 41 and the openings 5 are coaxially arranged.
Wherein, the crystal constant of the cellular structure is preferably 70mm to 90mm, for example 80mm, as shown in fig. 4, in this range, the optimal band gap structure can be obtained, and the noise reduction performance can be optimized. The radius of the spherical ring is from outside to inside in sequence from R1 to 34mm to 36mm, for example 35 mm; r2 ═ 30mm to 32mm, for example 31 mm; r3 ═ 22mm to 24mm, for example, 23.3 mm; r4 ═ 19mm to 21mm, for example 20.6 mm; r5 ═ 15mm to 17mm, for example 15.5 mm; r6 is 13mm to 15mm, for example 13.7 mm. Gap height dh1 ═ 20mm, dh2 ═ 13.2mm, dh3 ═ 8.8 mm. Preferably, the ratio of the radius to the height dimension of the notch opening 5 is 1:1.5 from inside to outside;
preferably, the thickness of the three layers of foamed aluminum 4 is 4mm, 2.7mm and 1.8mm from outside to inside respectively, the thickness of the whole cellular structure is equal to the length of the opening, and the length of the opening is 1.5 times of the height of the opening and is 30mm, as shown in fig. 5.
Preferably, the sound barrier substructure comprises an air layer 6 (i.e. this layer is air, no other material is added), a porous sound-absorbing material 7, an open-pore metal plate 8, a solid metal plate 9, the sound barrier one-dimensional phononic crystal quasi-periodic structure in fig. 6 is, starting from the noise source side, the open-pore metal plate 8, the air layer 6 and the porous sound-absorbing material layer 7 which are alternately distributed, and the solid metal plate 9, the open-pore metal plate 8 is on the noise source side, and the solid metal plate 9 is on the other side. The perforated metal plate 8 and the solid metal plate 9 are high-quality galvanized steel plates, the galvanizing thickness is more than or equal to 90 mu m, the toughness of a zinc layer is high, the surface of the metal plate is prevented from being corroded, and the service life of the metal plate is prolonged; the porous sound absorption material is rock wool or urethane foam plastic;
preferably, the thickness of the air layer is adjusted by introducing a periodic function to introduce an inner period in the phononic crystal beam, the thickness of the air layer being as shown in the following equation:
dA(i)＝dA(1+αcos2πδ(i)/n)
where δ (i) ═ 0, ± 1, ± 2ADenotes the initial thickness, dA(i) Indicates the ith air layerThe thickness, the constant n is a modulation parameter, the variable delta is used for changing the modulation intensity, the variable alpha is used for influencing the component ratio of the structure, the component ratio of the material has a great influence on the quasi-periodic structure band gap of the one-dimensional phononic crystal, and the optimal alpha is 0.5 according to the known literature. The air layers and the porous sound absorption materials are alternately arranged, wherein the thickness of the air layers is periodically changed, the unit cell structure of the air layers is a composite structure formed by combining n continuous different single units, the thickness of the air layers 6 is sequentially set to be 2mm, 4mm, 6mm, 8mm and 10mm from left to right, the porous sound absorption material layers 7 are clamped between the air layers 6, the thickness of each air layer is 10mm, the outermost sides of each air layer are respectively provided with a solid metal plate 9 and an open pore metal plate 8, the thickness of each air layer is set to be 12mm, the total thickness of the lower parts of the whole sound barrier units is 80 mm-120 mm, for example 100mm, and the total height of.
By introducing the thickness of the periodic function air layer A, the thickness of the air layer A shows a repeated periodic change, so that the tuning phononic crystal shows multiple periodicities, the total bandwidth of the band gap in the structure is increased (by about 2.26 times), and the generated band gap covers each frequency band, so that the vibration reduction and noise reduction of multiple frequency bands are realized more easily. Within the passband frequencies, where the bending wave can propagate normally along the axial direction without significant attenuation, the tuned phononic crystal layer can be considered a filter. Waves in the pass band may pass through the filter with little attenuation, while waves in the forbidden band pass through the filter with attenuation, better control of vibration and noise reduction.
Preferably, the porous sound absorption material 7 with the one-dimensional phononic crystal quasiperiodic structure is matched with an air layer, and the low-frequency sound absorption and energy absorption of the porous sound absorption material are greatly enhanced. When sound waves are incident on the surface of the porous material, a part of the sound waves penetrate into the material, and a part of the sound waves are reflected on the surface of the material. The sound wave penetrating into the material is transmitted in the gaps and the small holes, the air movement can generate viscous and frictional action, meanwhile, the temperature of the air in the small holes is increased when the air is compressed, the temperature is reduced when the air is sparse, and the heat conduction effect of the material is achieved, so that the sound energy is gradually converted into heat energy to be consumed;
part of noise firstly passes through an inlet hole 15 of the hollow metal plate 8 with the single-side opening, then passes through the porous sound-absorbing material 7, is transmitted into the air layer 6, and is repeatedly transmitted in this way, most of the noise is weakened when being transmitted to the solid metal plate 9 through the vibration and noise reduction characteristics of the quasi-periodic structure of the one-dimensional phononic crystal, and most of the noise reflected by sound waves is repeatedly reduced through the porous sound-absorbing material 7 and the air layer 6 and almost completely absorbed; residual noise enters from an opening of the upper structure of the sound barrier and enters into the three-dimensional gas-solid local resonance type photonic crystal cavity, sound waves are reflected in the sound cavity and are repeatedly absorbed, and partial energy is absorbed by the damping material;
preferably, the high-quality galvanized steel plate and the air layer have different acoustic impedances, wherein the acoustic impedance of the galvanized steel plate is larger than that of the air layer, so that an acoustic impedance gradient is formed, and the propagation of noise is more favorably inhibited;
preferably, the metal plate has an opening ratio of more than 35% and can reduce high-frequency noise, and the metal plate has an opening ratio of less than 25% and can reduce low-frequency noise;
preferably, the sound barrier substructure and the concrete foundation 14 are connected and fixed through angle steel 13, metal backing plate 12, bolt 10 and nut 11.
Preferably, the cross section of the concrete base 14 is an isosceles trapezoid structure, the concrete strength is C50, a spiral sleeve 16 is arranged in the concrete base 14, the top of the spiral sleeve 16 is flush with the bottom concrete support 14, and the other parts of the spiral sleeve are embedded in the concrete base 14, so that the connection between the lower structure of the sound barrier and the concrete base 14 is enhanced.
The above description is only the preferred embodiment of the present invention, and the protection scope of the present invention is considered on the premise of the principle of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (10)
1. The utility model provides a compound sound barrier structure based on phononic crystal which characterized in that: the sound barrier structure comprises a sound barrier unit upper part and a sound barrier unit lower part, wherein the sound barrier unit upper part comprises two plates which are arranged in a V shape, so that the sound barrier unit upper part and the sound barrier unit lower part are integrally combined into a Y shape, the barrier unit upper part comprises foamed aluminum, and the sound barrier unit lower part comprises an air layer.
2. A phononic crystal-based composite sound barrier structure as claimed in claim 1, characterized in that: each plate on the upper part of the sound barrier unit comprises a metal shell, and a damping material and a cellular structure which are arranged in the metal shell, wherein the cellular structure comprises the foamed aluminum; an opening is formed in the metal shell and faces the direction of a noise source, a cellular structure is connected to each opening, and damping materials are filled outside the cellular structures in the metal shell.
3. A phononic crystal-based composite sound barrier structure as claimed in claim 2, characterized in that: the cellular structure is a round cake shape and comprises three layers of spherical annular foamed aluminum and cellular cavities positioned between adjacent foamed aluminum layers and in the innermost foamed aluminum layer, wherein each layer of foamed aluminum is provided with a notch, and the notches and the openings are coaxially arranged.
4. A phononic crystal based composite sound barrier structure as claimed in claim 3, characterized in that: the opening height of the gap of the three layers of spherical annular foamed aluminum is reduced along with the reduction of the radius.
5. A phononic crystal based composite sound barrier structure as claimed in claim 3, characterized in that: the ratio of the radius of the spherical ring-shaped foamed aluminum to the height of the gap is 1:1.5 from inside to outside.
6. A phononic crystal-based composite sound barrier structure as claimed in claim 2, characterized in that: the metal shells of the two plates are integrally formed.
7. A phononic crystal-based composite sound barrier structure as claimed in claim 1, characterized in that: the lower part of the sound barrier unit comprises an open-hole metal plate, air layers and porous sound absorption material layers which are alternately distributed, and a solid metal plate, wherein the open-hole metal plate is arranged on one side of a noise source, and the solid metal plate is arranged on one side far away from the sound source.
8. A phononic crystal based composite sound barrier structure as claimed in claim 7, characterized in that: the thickness of the air layer varies periodically.
9. A phononic crystal based composite sound barrier structure as claimed in claim 8, wherein: the thickness of the air layer satisfies the following formula, dA(i)＝dA(1+ α cos2 π δ (i)/n), where δ (i) ═ 0, ± 1, ± 2ADenotes the initial thickness, dA(i) The ith air layer thickness is expressed, the constant n is a modulation parameter, the variable delta is used for changing the modulation intensity, and the variable alpha is used for influencing the composition ratio of the structure.
10. A phononic crystal-based composite sound barrier structure as claimed in claim 1, characterized in that: the sound barrier structure further comprises a bottom support formed by trapezoidal concrete, and the lower portion of the sound barrier unit is connected with the trapezoidal concrete through a bolt and a spiral sleeve metal base plate.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111028820A (en) * | 2019-11-14 | 2020-04-17 | 南京航空航天大学 | Multilayer structure trompil formula phononic crystal board |
| CN115748528A (en) * | 2022-11-23 | 2023-03-07 | 兰州交通大学 | Rail transit sound barrier based on four composite partition plate primitive cells |
-
2020
- 2020-02-20 CN CN202020191551.1U patent/CN212426813U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111028820A (en) * | 2019-11-14 | 2020-04-17 | 南京航空航天大学 | Multilayer structure trompil formula phononic crystal board |
| CN115748528A (en) * | 2022-11-23 | 2023-03-07 | 兰州交通大学 | Rail transit sound barrier based on four composite partition plate primitive cells |
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