Composite sound barrier structure

Abstract

The utility model provides a composite sound barrier structure which comprises a sound barrier main body, and the sound barrier main body comprises a supporting device; the micro-perforated plate layer is located on the first side of the supporting device in the thickness direction, and the micro-perforated plate layer is connected with the supporting device; the noise reduction cavity layer is located on the second side of the supporting device in the thickness direction, the noise reduction cavity layer is connected with the supporting device, the noise reduction cavity layer is provided with a plurality of noise reduction cavities, and the noise reduction cavities are used for exciting sound energy to resonate with the air columns so as to consume the sound energy; and the gradient density sound absorption material layer is located between the micro-perforated plate layer and the noise reduction cavity layer, and the densities of at least part of sound absorption materials of the gradient density sound absorption material layer are different in the thickness direction of the supporting device. The problem that in the prior art, the noise reduction effect of a passive sound barrier is poor is solved.

Description

Technical Field

[0001] This utility model relates to the technical field of road sound barrier structures, and more specifically, to a composite sound barrier structure. Background Technology

[0002] Traffic noise currently exhibits strong randomness in both space and time, and its impact area is relatively large with a long duration of harm. Traffic noise control can be achieved in three stages: suppressing the noise source, suppressing the propagation of noise, and controlling it at the noise receiving point. In principle, this can be divided into active noise reduction and passive noise reduction technologies.

[0003] With the increasing severity of traffic noise pollution, sound barriers have been widely used as a primary noise reduction method in roads, railways, and other scenarios. Existing technologies are mainly divided into two categories: passive sound barriers and active noise reduction systems. Traditional sound barriers are mostly passive, often using single-layer porous materials (such as glass wool or rock wool) or micro-perforated panels. Active noise reduction systems are more expensive, and existing passive sound barriers only cover a portion of the frequency band, resulting in poor noise reduction performance.

[0004] There is currently no effective solution to the aforementioned problems in the existing technology. Utility Model Content

[0005] The main purpose of this invention is to provide a composite sound barrier structure to solve the problem of poor noise reduction effect of passive sound barriers in the prior art.

[0006] To achieve the above objectives, according to one aspect of the present invention, a composite sound barrier structure is provided, comprising a sound barrier body, the sound barrier body comprising: a support device; a micro-perforated plate layer located on a first side in the thickness direction of the support device, the micro-perforated plate layer being connected to the support device, the micro-perforated plate layer having multiple micropores, the micropores being used to generate frictional loss of sound energy through the neck of the pores to dissipate sound energy; a noise reduction cavity layer located on a second side in the thickness direction of the support device, the noise reduction cavity layer being connected to the support device, the noise reduction cavity layer having multiple noise reduction cavities, the noise reduction cavities being used to excite sound energy to resonate with the air column to dissipate sound energy; and a gradient density sound-absorbing material layer located between the micro-perforated plate layer and the noise reduction cavity layer, wherein, along the thickness direction of the support device, at least a portion of the sound-absorbing material in the gradient density sound-absorbing material layer is provided with different densities.

[0007] Furthermore, the density of the gradient density sound-absorbing material layer is arranged to increase linearly from the first side to the second side of the support device.

[0008] Furthermore, the gradient slope of the linearly increasing density of the gradient density sound-absorbing material layer is Z, where 10 kg / m 3 / mm≥Z≥5kg / m3 / mm.

[0009] Furthermore, the gradient density sound-absorbing material layer includes multiple sub-density layers, each with a different density of sound-absorbing material. The multiple sub-density layers are arranged in a preset order and then hot-pressed to form the gradient density sound-absorbing material layer. The density of the gradient density sound-absorbing material layer increases sequentially from the first side to the second side of the support device.

[0010] Furthermore, the density of the sound-absorbing material within the sub-density layer is A, where 200 kg / m³ 3 ≥A≥80kg / m 3 .

[0011] Furthermore, the sound-absorbing material of the gradient density sound-absorbing material layer is glass fiber cotton, and at least one surface of the glass fiber cotton is coated with a hydrophobic agent.

[0012] Furthermore, the noise reduction cavity is a Helmholtz resonant cavity, which includes a cavity and a neck connected to the cavity. The cross-sectional shape of the cavity is one of the following: circular, elliptical, polygonal, or irregular.

[0013] Furthermore, the diameter of the cavity is D1, 60mm≥D1≥400mm, the length of the neck is L1, 8mm≥L1≥12mm, and the diameter of the neck is D2, 4mm≥D2≥6mm.

[0014] Furthermore, the gradient density sound-absorbing material layer includes a substrate and noise-reducing cavities. The noise-reducing cavities are arranged in an alternating array on the substrate. Along the transverse direction of the substrate, the distance between two adjacent noise-reducing cavities is L2, where 1.8*L1≥L2≥1.5*L1. Along the longitudinal direction of the substrate, the distance between two adjacent noise-reducing cavities is L3, where 1.1*L1≥L3≥0.9*L1.

[0015] Furthermore, the microperforated plate layer has multiple arrayed micropores with a pore diameter of D2, 0.3 mm ≥ D2 ≥ 0.1 mm, and / or, the perforation rate of the microperforated plate layer is B, 30% ≥ B ≥ 25%, and / or, the thickness of the microperforated plate layer is C, 3 mm ≥ C ≥ 1 mm.

[0016] Furthermore, the composite sound barrier structure also includes a flow guide wing structure, which is located on top of the support device. The first end of the flow guide wing structure is connected to the top of the support device, and the second end of the flow guide wing structure extends away from the support device.

[0017] Furthermore, when the composite sound barrier structure is in the installation position, the second end of the guide wing structure extends along the direction of the sound source.

[0018] Furthermore, the guide vane structure and the support device are set at an angle, with the angle being E, where 17°≥E≥13°.

[0019] Furthermore, the guide vane structure is an arc-shaped plate, and the radius of curvature of the guide vane structure is F, 60mm≥F≥40mm.

[0020] Furthermore, the air deflector structure is detachably connected to the support device via snap-fit.

[0021] By applying the technical solution of this utility model, the main body of the sound barrier is composed of a micro-perforated plate layer, a noise reduction cavity layer, and a gradient density sound-absorbing material layer. The gradient density sound-absorbing material layer has at least a portion of its sound-absorbing material with different densities, creating a gradient impedance structure in the main body of the sound barrier. The three layers absorb noise in different frequency ranges. The micro-perforated plate layer reflects high-frequency noise and guides mid-to-low frequency sound waves into the gradient density sound-absorbing material layer. The gradient density sound-absorbing material layer broadens the sound absorption frequency band through impedance matching, and the noise reduction cavity layer absorbs low-frequency noise, thereby improving the sound absorption coefficient of the main body of the sound barrier. This application solves the problem of poor noise reduction performance of passive sound barriers in the prior art. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0023] Figure 1 A schematic diagram of the structure of the first embodiment of the composite sound barrier structure according to the present invention is shown;

[0024] Figure 2 A schematic diagram of a second embodiment of the composite sound barrier structure according to the present invention is shown;

[0025] Figure 3 A schematic diagram of an embodiment of the noise reduction cavity layer according to the present invention is shown;

[0026] Figure 4 A schematic diagram of a third embodiment of the composite sound barrier structure according to the present invention is shown;

[0027] Figure 5 A schematic diagram of an embodiment of the noise reduction cavity according to the present invention is shown.

[0028] The above figures include the following reference numerals:

[0029] 1. Micro-perforated plate layer;

[0030] 2. Noise reduction cavity layer;

[0031] 3. Gradient density sound-absorbing material layer;

[0032] 4. Cavity;

[0033] 5. Neck;

[0034] 6. Guide vane structure;

[0035] 7. Noise sources;

[0036] 8. High-frequency sound waves;

[0037] 9. Low and mid-frequency sound waves;

[0038] 10. Low-frequency sound waves. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0042] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0043] Combination Figures 1 to 5 As shown, according to a specific embodiment of this application, a composite sound barrier structure is provided.

[0044] A composite sound barrier structure includes a sound barrier body, which comprises: a support device; a micro-perforated plate layer 1, located on the first side of the support device in the thickness direction and connected to the support device, the micro-perforated plate layer 1 having multiple micropores, the micropores being used to dissipate sound energy by generating frictional loss through the neck of the pores; a noise reduction cavity layer 2, located on the second side of the support device in the thickness direction and connected to the support device, the noise reduction cavity layer 2 having multiple noise reduction cavities, the noise reduction cavities being used to excite sound energy to resonate with the air column to dissipate sound energy; and a gradient density sound-absorbing material layer 3, located between the micro-perforated plate layer 1 and the noise reduction cavity layer 2, wherein at least a portion of the sound-absorbing material in the gradient density sound-absorbing material layer 3 is set with different densities along the thickness direction of the support device.

[0045] Single-layer porous sound-absorbing materials use porous materials such as glass wool, rock wool, or polyester fibers to dissipate sound energy through friction within the material's pores. Typical parameters include: 1. Thickness (50-100mm); 2. Sound absorption coefficient (>0.8@500-2000Hz, <0.3@100-300Hz). This structure has the following drawbacks: 1. Poor low-frequency performance: High pore resonant frequency, unable to effectively absorb low-frequency components in traffic noise (such as tire noise at 100-300Hz). 2. Environmental sensitivity: Fibers harden in humid environments, reducing sound absorption performance by 30%-50%. 3. Secondary pollution: Microparticles are released after material aging, requiring an additional encapsulation layer (increasing cost by 20%).

[0046] Micro-perforated panel structures utilize uniformly distributed micropores (0.1-0.5mm in diameter) on metal or plastic plates, employing air friction at the pore necks and back cavity resonance for sound absorption. Typical parameters include perforation rate (1%-5%) and absorption peak: narrow band (±50Hz), e.g., a 200Hz design only covers 150-250Hz. The drawbacks of this approach are as follows: 1. Narrow bandwidth: only targeting a single frequency band, unable to cover the wideband characteristics of traffic noise (50-2000Hz). 2. High-frequency reflection: the rigidity of the panel results in a reflectivity >30% for sound waves >1kHz, requiring an additional sound-absorbing layer. 3. Sensitive to wind noise: strong winds passing through the micropores generate a whistling sound; noise increases by 3-5dB at wind speeds of 10m / s.

[0047] The Helmholtz resonator array arranges resonant cavities (cavity + neck) on the surface of the sound barrier, absorbing specific low frequencies through resonant air springs within the cavities. Typical parameters include resonant frequency: 100-300Hz (cavity diameter 50mm, neck length 10mm) and absorption coefficient (0.6-0.9@resonant frequency, <0.2@non-resonant frequency band). This approach has the following drawbacks: 1. Limited frequency band: Effective only within ±10% of the design frequency, failing to cover wideband requirements. 2. Low space utilization: Dense arrangement of resonant cavities increases the barrier thickness (>150mm), making it difficult to adapt to existing structural modifications. 3. High manufacturing precision requirements: A ±1mm deviation in neck dimensions can cause a 20Hz shift in resonant frequency.

[0048] If only the outer layer is a soundproof panel (such as a metal plate), and the inner layer is filled with a porous material, it can achieve both sound insulation and sound absorption. Typical parameters: sound insulation: 25-30dB@500Hz, sound absorption coefficient: 0.4-0.6@500-2000Hz. This solution has the following drawbacks: 1. Poor low-frequency sound insulation: Under the constraint of the mass law, the low-frequency sound insulation is <15dB@100Hz. 2. Sound reflection superposition: The rigid outer layer reflects sound waves, forming a standing wave in the center of the road, increasing the sound pressure level by 4-6dB. 3. High weight: density >30kg / m³. 2 The cost of the supporting structure increased by 40%.

[0049] The three-layer sound barrier body of this application constructs a gradient impedance layer: a surface microporous plate (>500Hz), a middle gradient cotton layer (200-800Hz), and a bottom resonant cavity (100-300Hz), which synergistically covers 50-2000Hz. This solves the problem of traditional solutions where a single technology only covers part of the frequency band (e.g., porous materials >500Hz, resonators 100-300Hz), achieving efficient sound absorption across the entire frequency band. The final sound absorption coefficient is >0.6@100-2000Hz, which is 40%-200% higher than traditional solutions (low frequency band).

[0050] Furthermore, the density of the gradient density sound-absorbing material layer 3 is arranged to increase linearly along the direction from the first side of the support device to the second side of the support device.

[0051] In other words, the density of the gradient density sound-absorbing material layer 3 gradually increases, and its production process can adopt one of the following technical means:

[0052] 1. Controlled Compression Process. Principle: Gradient compression of glass wool with uniform density. Steps: Initial Material Preparation: Prepare a glass wool board with uniform density. Mechanical Gradient Compression: Using a hydraulic press or roller press with inclined pressure plates, apply linearly increasing pressure to the material from left (low pressure, low density) to right (high pressure, high density), forming a density gradient. Curing and Shaping: Cure the compressed structure by heating or using an adhesive (such as phenolic resin) to maintain the density distribution.

[0053] 2. 3D Printing / Electrospinning Technology. Principle: Layer-by-layer fiber deposition with dynamic density adjustment. Steps: Set parameters for linear density variation in 3D modeling software. Printing Execution: Deposit glass fibers layer by layer using 3D printing equipment (e.g., combined with electrospinning technology), achieving density gradients by adjusting fiber spacing or nozzle speed. Post-processing: High-temperature sintering or bonding reinforcement.

[0054] 3. Mixed Foaming and Filling Process. Principle: Controlling local density by combining foaming agent and filler. Steps: Glass wool pretreatment: Immersing glass wool in a solution containing foaming agent. Gradient foaming: During heating, controlling the degree of foaming through a temperature gradient (lower temperature on the left → higher temperature on the right), making the right side denser. Filler reinforcement: Injecting high-density filler (such as microspheres) into the right side and curing.

[0055] Using the technical solution of this application, sound waves generated by the noise source (vehicle) propagate to the sound barrier. The surface layer is a micro-perforated panel with a pore size of 0.1-0.3 mm and a perforation rate of 25%-30%, reflecting high-frequency noise and guiding mid- and low-frequency sound waves into the middle layer. The middle layer is gradient-density sound-absorbing cotton with a density of 80→200 kg / m³. 3 Gradual density, 50-100mm thick, widens the sound absorption frequency band through impedance matching. The bottom Helmholtz resonant cavity: 50mm diameter, 10mm×5mm neck, selectively absorbs low-frequency noise from 100-300Hz. Airfoil structure: tilted at 15°, radius of curvature R=50mm, reducing the drag coefficient to 0.3. Support frame: galvanized steel frame (200×200mm mesh), fixing each layer of the structure. Furthermore, the gradient slope of the linearly increasing density of the gradient density sound-absorbing material layer 3 is Z, where 10kg / m³... 3 / mm≥Z≥5kg / m 3 / mm.

[0056] Furthermore, the gradient density sound-absorbing material layer 3 includes multiple sub-density layers, and the density of the sound-absorbing material in the multiple sub-density layers is set differently. After the multiple sub-density layers are arranged in a preset order, they are formed by hot pressing to form the gradient density sound-absorbing material layer 3. The density of the gradient density sound-absorbing material layer 3 is set to increase sequentially along the direction from the first side of the support device to the second side of the support device.

[0057] When using the passive sound barrier of this application, the sound wave transmission path is described as follows:

[0058] High-frequency sound wave path: Sound waves enter the middle layer through the holes of the micro-perforated plate, and the high-frequency energy (>500Hz) is consumed by air friction (viscous loss) at the neck of the hole.

[0059] Formula: High-frequency sound absorption coefficient Z plate The acoustic impedance of the micro-perforated plate.

[0060] Mid-to-low frequency sound wave path: Sound waves penetrate the gradient cotton layer, and the density gradually changes to achieve continuous acoustic impedance matching (from 415 Rayl in air to 2000 Rayl in cotton layer), reducing reflection.

[0061] Formulas for viscous resistance and heat loss;

[0062] ρ is density, η is dynamic viscosity, and d is thickness.

[0063] Low-frequency resonance path: The remaining acoustic energy enters the Helmholtz resonant cavity, exciting the air column to resonate (resonance frequency 100-300Hz), and the energy is converted into heat energy.

[0064] Resonance frequency formula: (A: Neck area, V: Cavity volume, L: Neck length).

[0065] The impedance gradient makes the reflectivity <10%@1kHz (compared to >30% for traditional structures), thus avoiding the formation of standing waves in the center of the road.

[0066] The structural parameters of the composite sound barrier in this application are shown in the table below:

[0067]

[0068] Furthermore, the density of the sound-absorbing material within the sub-density layer is A, where 200 kg / m³ 3 ≥A≥80kg / m 3 .

[0069] Specifically, the impedance matching principle of gradient density sound-absorbing cotton is explained as follows:

[0070] 1. Traditional homogeneous sound-absorbing cotton has the following acoustic defects:

[0071] Acoustic impedance abrupt change: Impedance mismatch at the interface between air (415Rayl) and homogeneous cotton (1400Rayl) results in 30% acoustic energy reflection.

[0072] Formula: Reflection Coefficient

[0073] 2. The impedance matching principle of the gradient density sound-absorbing cotton in this application is as follows:

[0074] Density gradient design: The density increases linearly from 80 kg / m3 (near air side) to 200 kg / m3 (near rigid substrate side), with a thickness of 80 mm and a slope of 8 kg / m3 / mm.

[0075] Acoustic impedance changes continuously and gradually: Acoustic impedance Z(x) = Z air +kx, where k is the gradient coefficient (≈20Rayl / mm), to achieve a smooth transition from 415Rayl to 2000Rayl.

[0076] The reflectivity is greatly reduced: Exponential decay reduces reflectivity to 5%.

[0077] The key parameters of the gradient density sound-absorbing cotton using this application and traditional homogeneous cotton are compared in the table below:

[0078]

[0079] The implementation details of gradient density sound-absorbing cotton technology include the following density gradient control process:

[0080] Laying technique: Fiber cotton of different densities (80 / 120 / 160 / 200kg / m3) is laid in a gradient and then hot-pressed together between layers.

[0081] Hot pressing parameters: temperature 150℃, pressure 10MPa, time 5 minutes, ensuring no gaps between layers.

[0082] Acoustic impedance calculation model for gradient density sound-absorbing cotton:

[0083] (ρ: density, E: dynamic elastic modulus). The dynamic elastic modulus E(x) is linearly related to the density ρ(x): E(x) = 0.5ρ(x) + 50.

[0084] The sound absorption performance of the gradient density sound-absorbing cotton of this application was verified by standing wave tube testing (according to ISO 10534-2), and the results are shown in the table below:

[0085]

[0086] Furthermore, the sound-absorbing material of the gradient density sound-absorbing material layer 3 is glass fiber cotton, and / or, at least one surface of the glass fiber cotton is coated with a hydrophobic agent.

[0087] Traditional solutions suffer from fiber compaction and significant wind noise interference due to humidity. The technical solution in this embodiment achieves a moisture-proof design: the surface of the middle layer of glass fiber cotton is coated with a hydrophobic agent (contact angle >120°), resulting in a performance decrease of <10% at 90% humidity.

[0088] Furthermore, the noise reduction cavity is a Helmholtz resonant cavity, which includes a cavity 4 and a neck 5 connected to the cavity 4. The cross-sectional shape of the cavity 4 is one of a circle, an ellipse, a polygon, or an irregular shape.

[0089] The diameter of cavity 4 is D1, 60mm≥D1≥400mm, the length of neck 5 is L1, 8mm≥L1≥12mm, and the diameter of neck 5 is D2, 4mm≥D2≥6mm.

[0090] like Figure 3 As shown, the gradient density sound-absorbing material layer 3 includes a substrate and noise reduction cavities. The noise reduction cavities are arranged in an alternating array on the substrate. Along the transverse direction of the substrate, the distance between two adjacent noise reduction cavities is L2, where 1.8*L1≥L2≥1.5*L1. Along the longitudinal direction of the substrate, the distance between two adjacent noise reduction cavities is L3, where 1.1*L1≥L3≥0.9*L1.

[0091] The cavity arrangement rules of the gradient density sound-absorbing material layer 3 are as follows: the horizontal spacing is 60mm and the vertical spacing is 50mm, arranged in an alternating pattern. 256 resonant cavities are arranged per square meter.

[0092] Using the above arrangement rules, the resonant frequency is calculated as follows:

[0093] V = π (25 mm) 2 ×30mm≈58,875mm 3 ;

[0094] A = π (2.5 mm) 2 ≈19.6mm 2 ;

[0095]

[0096] Manufacturing tolerance control: neck diameter tolerance ±0.1mm, cavity volume deviation <5%.

[0097] The impact of the above key parameters on the function of the noise reduction cavity is shown in the table below:

[0098]

[0099] The technical solutions adopted in the above embodiments have the following technical advantages, as shown in the table below:

[0100]

[0101] Traditional solutions require densely packed Helmholtz resonators (spacing < λ / 2) and a thickness > 150 mm. The technical solution presented in this application achieves a compact design: a three-layer structure with a total thickness of 100-120 mm, which can directly replace traditional barriers. Traditional active noise reduction systems cost as much as 150,000-200,000 RMB / km, while the sound barrier structure presented in this application only costs 80,000-120,000 RMB / km.

[0102] In traditional solutions, rigid structures reflect sound waves, forming standing waves. The technical solution presented in this application, through impedance gradient matching, reduces sound reflection (reflectivity <10%@1kHz), lowering the sound pressure level in the center of the road by 4-6dB and suppressing secondary noise.

[0103] Furthermore, the micro-perforated plate layer 1 has a plurality of micropores arranged in an array, the pore diameter of the micropores being D2, 0.3mm≥D2≥0.1mm, and / or, the perforation rate of the micro-perforated plate layer 1 being B, 30%≥B≥25%, and / or, the thickness of the micro-perforated plate layer 1 being C, 3mm≥C≥1mm.

[0104] In one optional embodiment, the micro-perforated plate has a pore size of 0.1-0.3 mm, a perforation rate of 25%-30%, and a pore spacing of 8-12 times the pore size. Gradient density sound-absorbing cotton: the density of the sound-absorbing cotton ranges from 80 kg / m² along the thickness direction. 3 Linearly increase to 200 kg / m 3 The gradient slope is 5-10 kg / m 3 / mm. The density gradient can be continuous or discontinuous. Helmholtz resonator: In a resonator array, the diameter of a single cavity is 40-60mm, the neck length is 8-12mm, and the lateral spacing is 1.2-1.5 times the cavity diameter. The shape of the resonator can be circular, elliptical, polygonal, or square, etc., without limitation on the specific shape.

[0105] Furthermore, the composite sound barrier structure also includes a guide wing structure 6, which is located on top of the support device. The first end of the guide wing structure 6 is connected to the top of the support device, and the second end of the guide wing structure 6 extends away from the support device.

[0106] Anti-wind noise structure: The airfoil design reduces the drag coefficient to 0.3. Combined with the anti-wind noise algorithm, the noise reduction fluctuation is ≤±2dB at a wind speed of 10m / s.

[0107] Furthermore, when the composite sound barrier structure is in the installation position, the second end of the guide wing structure 6 extends along the direction of the sound source.

[0108] Furthermore, the guide vane structure 6 is set at an angle with the support device, the angle being E, 17°≥E≥13°.

[0109] Furthermore, the guide vane structure 6 is an arc-shaped plate, and the radius of curvature of the guide vane structure 6 is F, where 60mm ≥ F ≥ 40mm.

[0110] The airfoil has a tilt angle of 15° ± 2°, which optimizes the balance between aerodynamic performance and noise reduction. The radius of curvature of the airfoil is R = 50mm, ensuring a smooth airflow transition and avoiding local acceleration.

[0111] Airfoil surface treatment: Nano-hydrophobic coating reduces rainwater retention and prevents icing and dust accumulation.

[0112] In traditional vertical structures, airflow separates at the barrier edge, creating a large turbulent zone. At a wind speed of 10 m / s, wind noise is ≥55 dB(A), and the drag coefficient is 0.8.

[0113] The airfoil structure described in this application allows for smooth airflow along the airfoil surface, reducing turbulence intensity by 70%. The drag coefficient is 0.3, and the wind noise is ≤45dB(A).

[0114] The wind tunnel test data are shown in the table below:

[0115]

[0116] The airfoil structure adopted in this embodiment achieves aerodynamic-acoustic synergistic design, balancing airfoil curvature and tilt angle with structural strength. Simultaneously, it integrates a hydrophobic coating, achieving a contact angle >120° and a rainwater sliding-off time <2 seconds.

[0117] Furthermore, the airfoil structure 6 is detachably connected to the support device via snap-fit ​​connections. The airfoil units are connected via snap-fit ​​connections (200mm spacing), supporting quick replacement.

[0118] The following table shows the comparison results of the acoustic performance tests between the sound barrier structure using this application and the traditional system:

[0119]

[0120] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0121] 1. Full-frequency sound absorption: Through the synergistic effect of micro-perforated plate (high frequency), gradient cotton (mid frequency), and resonant cavity (low frequency), wide-frequency noise reduction of 50-2000Hz is achieved.

[0122] 2. Environmental adaptability: The airfoil design reduces wind noise, and the moisture-proof design ensures performance in humid and hot environments.

[0123] 3. Engineering Feasibility: Modular design adaptable to existing barrier renovations, total thickness 120mm, weight ≤25kg / m 2 .

[0124] The technical solution of this application realizes gradient impedance matching design. Its essence lies in achieving a continuous, gradual change in acoustic impedance from air to a rigid barrier through a composite layered structure of micro-perforated plates, gradient-density sound-absorbing cotton, and a Helmholtz resonant cavity. This reduces sound wave reflection and improves sound absorption efficiency across the entire frequency range. Traditional structures rely on only a single material (such as porous cotton or a resonant cavity). This invention, through a synergistic mechanism of gradual impedance change, breaks through the low-frequency sound absorption bottleneck (increasing the sound absorption coefficient from 0.3 to 0.8@200Hz). It also provides the optimal parameter combination (within experimental verification range) for the micro-perforated plate aperture and the gradient density slope.

[0125] The technical solution adopted in this application achieves synergistic sound absorption through multiple mechanisms. The core technologies are: High frequency band (>500Hz): frictional loss at the neck of the micro-perforated plate; Mid frequency band (200-500Hz): viscous resistance sound absorption of gradient density cotton; Low frequency band (<200Hz): air spring effect of the Helmholtz resonator. The three-layer structure optimizes frequency band division and energy transfer paths, covering the entire frequency range of 50-2000Hz. The spatial coupling design between the resonator array and the gradient cotton avoids standing wave interference.

[0126] The technical solution of this application achieves an anti-environmental interference design. The core technology is a guide airfoil structure: a 15° inclined curved surface design reduces the drag coefficient to 0.3, suppressing wind noise. The gradient cotton surface is coated with a hydrophobic agent (contact angle >120°), resulting in a performance decrease of <10% at 90% humidity. The combination of structural design and material modification solves the performance degradation problem of traditional sound barriers in strong winds and humid environments.

[0127] Specifically, micro-perforated panels, gradient-density sound-absorbing cotton, and a Helmholtz resonator are layered sequentially, causing the acoustic impedance to gradually change from 415 Rayl (air) at the surface to 1.5 × 10⁶ Rayl (rigid matrix) at the bottom. High-frequency sound waves (>500Hz) are absorbed by the micro-perforated panels, mid-frequency sound waves (200-500Hz) by the gradient-density sound-absorbing cotton, and low-frequency sound waves (<200Hz) by the Helmholtz resonator, reflecting the frequency band division control logic. The top of the sound barrier is equipped with a flow-guiding airfoil structure with an inclination angle ranging from 10° to 20° and a radius of curvature ranging from 30 to 50 mm, realizing an anti-environmental interference design flow-guiding airfoil structure. The surface of the gradient-density sound-absorbing cotton is coated with a hydrophobic agent, and its contact angle with water is greater than 120°.

[0128] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0129] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this utility model.

[0130] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0131] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A composite sound barrier structure, characterized by, The sound barrier body comprises: a support device; a micro-perforated plate layer (1) located on a first side of the support device in the thickness direction, connected with the support device, having a plurality of micro-holes for consuming sound energy by friction loss of hole necks; a noise reduction cavity layer (2) located on a second side of the support device in the thickness direction, connected with the support device, having a plurality of noise reduction cavities for exciting sound energy to resonate with air columns to consume sound energy; a gradient density sound absorption material layer (3) located between the micro-perforated plate layer (1) and the noise reduction cavity layer (2) along the thickness direction of the support device, at least part of the sound absorption material in the gradient density sound absorption material layer (3) being arranged differently in density.

2. The composite sound barrier structure of claim 1, wherein, The density of the gradient density sound absorption material layer (3) is arranged linearly from the first side of the support device to the second side of the support device.

3. The composite sound barrier structure of claim 2, wherein, The gradient density sound-absorbing material layer (3) has a linearly increasing gradient slope Z, wherein 10 kg / m 3 / mm≥Z≥5 kg / m 3 / mm.

4. The composite sound barrier structure of claim 1, wherein, The gradient density sound absorption material layer (3) comprises a plurality of sub-density layers, the density of the sound absorption material in the plurality of sub-density layers being arranged differently, and the plurality of sub-density layers are arranged in a predetermined order and formed into the gradient density sound absorption material layer (3) by hot pressing, the density of the gradient density sound absorption material layer (3) being arranged sequentially from the first side of the support device to the second side of the support device.

5. The composite sound barrier structure of claim 4, wherein, The density of the sound absorption material in the sub-density layer is A, wherein 200 kg / m 3 ≥ A ≥ 80 kg / m 3 .

6. The composite sound barrier structure of claim 1, wherein, The sound absorption material in the gradient density sound absorption material layer (3) is glass fiber cotton, and at least one surface of the glass fiber cotton is coated with a hydrophobic agent.

7. The composite sound barrier structure of claim 1, wherein, The noise reduction cavity is a Helmholtz resonance cavity, which comprises a cavity (4) and a neck (5) in communication with the cavity (4), and the cross-sectional shape of the cavity (4) is one of circular, elliptical, polygonal and special-shaped.

8. The composite sound barrier structure of claim 7, wherein, The diameter of the cavity (4) is D1, 60mm≥D1≥400mm, the length of the neck (5) is L1, 8mm≥L1≥12mm, and the diameter of the neck (5) is D2, 4mm≥D2≥6mm.

9. The composite sound barrier structure of claim 8, wherein, The gradient density sound absorption material layer (3) comprises a substrate and the noise reduction cavities arranged in an interleaved array on the substrate, wherein the distance between two adjacent noise reduction cavities along the transverse direction of the substrate is L2, wherein 1.8*L1≥L2≥1.5*L1, and the distance between two adjacent noise reduction cavities along the longitudinal direction of the substrate is L3, wherein 1.1*L1≥L3≥0.9*L1.

10. The composite sound barrier structure of claim 1, wherein, The micro-perforated plate layer (1) has a plurality of arrayed micro-holes, the aperture of the micro-holes is D2, 0.3mm≥D2≥0.1mm, and / or the perforation rate of the micro-perforated plate layer (1) is B, 30%≥B≥25%, and / or the thickness of the micro-perforated plate layer (1) is C, 3mm≥C≥1mm.

11. The composite sound barrier structure of claim 1, wherein, The composite sound barrier structure further comprises a flow guide wing structure (6) located at the top of the support device, a first end of the flow guide wing structure (6) being connected with the top end of the support device, and a second end of the flow guide wing structure (6) extending in a direction away from the support device.

12. The composite sound barrier structure of claim 11, wherein, When the composite sound barrier structure is located at the installation position, the second end of the flow guide wing structure (6) extends in a direction of a sound source.

13. The composite sound barrier structure of claim 11, wherein, The flow guide wing structure (6) is arranged at an included angle with the support device, and the included angle is E, 17°≥E≥13°.

14. The composite sound barrier structure of claim 13, wherein, The flow guide wing structure (6) is an arc-shaped plate, and a radius of curvature of the flow guide wing structure (6) is F, 60mm≥F≥40mm.

15. The composite sound barrier structure of claim 11, wherein, The flow guide wing structure (6) is detachably connected with the support device through buckling.

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