Sound barrier device based on Bragg scattering, cavity resonance and micropore principle

Abstract

The invention discloses a sound barrier device based on Bragg scattering, cavity resonance and micropore principles, the device is provided with a sound barrier top end structure, and the noise reduction effect is enhanced through the top end structure; the device comprises a screen body, the top end structure of the screen body is provided with a supporting assembly and a sound wave scattering array assembly, the sound wave scattering array assembly is arranged based on the supporting assembly, and the device scatters different frequency components in noise sound waves through the sound wave scattering array assembly on the basis of the Bragg scattering, cavity resonance and micropore principle, so that the sound wave scattering effect is improved. Therefore, the sound energy of noise sound waves is reduced. Noise sound waves can be reduced step by step in combination with Bragg scattering, cavity resonance and micro-perforation theories, so that linear propagation and top diffraction of the noise sound waves can be reduced, and the noise level is reduced.

Description

Technical Field

[0001] The present application belongs to the field of noise control technology, and specifically relates to a sound barrier device based on Bragg scattering, cavity resonance and micropore principles. Background Art

[0002] As a form of noise reduction to control noise propagation, sound barriers are the most widely used in the transportation field and are recognized as the most effective measure. Figure 1 As shown in the figure, by inserting a sound barrier between the sound source and the sound receiving point, the noise can be prevented from directly reaching the sound receiving point. After the sound barrier is inserted, except for a small part of the noise that reaches the sound receiving point through transmission and multiple reflections, most of the noise will be diffracted to the sound receiving point through the top of the sound barrier. The inserted sound barrier changes the propagation path of the sound wave, indirectly increases the attenuation propagation distance, and plays a role in reducing the sound pressure at the sound receiving point.

[0003] At present, in the design of road sound barriers, noise reduction devices with structures as shown in Figures 2 (a) to 2 (h) are usually used. Although these types of noise reduction devices can achieve noise reduction effects to a certain extent, due to defects in structural design, their effects on attenuating diffracted sound are limited, resulting in the overall noise reduction effect being difficult to achieve as expected. In addition, since the dominant factors of different road noises are different, for example, highways are mainly caused by friction noise between tires and pavement, while urban streets may be more affected by acceleration and braking noise, which leads to different main noise frequency bands. The traditional sound barrier design is not optimized according to these different noise characteristics, thus limiting its noise reduction effect in specific application scenarios. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a sound barrier device based on the principles of Bragg scattering, cavity resonance and micropores. The present application aims to improve the noise reduction effect by optimizing the structure of the existing noise reduction device.

[0005] To achieve the above objectives, this application provides the following technical solutions: A sound barrier device based on the principles of Bragg scattering, cavity resonance and micropores, the device having a sound barrier top structure, which can enhance the noise reduction effect through the top structure; The device comprises: Screen, The top structure of the screen body is provided with a support component and a sound wave scattering array component, wherein: The acoustic wave scattering array assembly is arranged based on the supporting assembly, The device is based on the principles of Bragg scattering, cavity resonance and micropores, and scatters different frequency components in noise sound waves through the sound wave scattering array component to reduce the sound energy of the noise sound waves.

[0006] Optionally, the acoustic wave scattering array assembly includes: a first scattering layer, a second scattering layer and a third scattering layer, and the first scattering layer, the second scattering layer and the third scattering layer constitute an asymmetric multilayer structure.

[0007] Optionally, the first scattering layer includes: a first scatterer, a second scatterer and a third scatterer, and the first scatterer, the second scatterer and the third scatterer constitute a first scattering interface.

[0008] Optionally, the second scattering layer includes: a fourth scatterer and a fifth scatterer, and the fourth scatterer and the fifth scatterer constitute a second scattering interface.

[0009] Optionally, the third scattering layer includes: a sixth scatterer, and the sixth scatterer constitutes a third scattering interface.

[0010] Optionally, the first scattering layer, the second scattering layer and the third scattering layer are arranged in sequence along a propagation path of a noise source.

[0011] Optionally, microporous plates are disposed in the first to sixth scatterers.

[0012] Optionally, the perforation rate of the microporous plate is 3%.

[0013] Optionally, the supporting assembly includes a base plate, a first side plate and a second side plate, the base plate and the screen body are fixedly connected, and the first side plate and the second side plate extend along a vertical direction of the acoustic wave scattering array assembly to form a semi-enclosed space structure with the base plate.

[0014] Optionally, the first side plate is provided with a first hole structure, the second side plate is provided with a second hole structure symmetrical to the first hole structure, and the first hole structure and the second hole structure correspond to the first scattering layer, the second scattering layer and the third scattering layer.

[0015] Compared with the prior art, the beneficial effects brought by the present application are: the present application can fully cover all specific frequencies in the noise sound waves, whether it is low-frequency noise, medium-frequency noise or high-frequency noise, it can be dispersed based on the device described in the present application, thereby reducing the noise level and improving the acoustic quality of the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the propagation path of noise sound waves; FIG2 (a) is a schematic diagram of the structure of an upright noise reduction device; FIG2( b ) is a schematic diagram of the structure of a T-type noise reduction device; Figure 2 (c) is a schematic diagram of the structure of a Y-type noise reduction device; Figure 2 (d) is a schematic diagram of the structure of an arc-shaped noise reduction device; Figure 2 (e) is a schematic diagram of the structure of an inverted L-shaped noise reduction device; Figure 2 (f) is a schematic diagram of the structure of a cylindrical noise reduction device; Figure 2 (g) is a schematic diagram of the structure of a chamber type noise reduction device; Figure 2 (h) is a schematic diagram of the structure of a deer horn type noise reduction device; Figure 3 It is a front view of a sound barrier device based on Bragg scattering, cavity resonance and micropore principles provided by another embodiment of the present application; Figure 4 It is a rear view of a sound barrier device based on Bragg scattering, cavity resonance and micropore principles provided by another embodiment of the present application; Figure 5 It is a side view of a sound barrier device based on Bragg scattering, cavity resonance and micropore principles provided by another embodiment of the present application; Figure 6 is a top view of a sound barrier device based on Bragg scattering, cavity resonance and micropore principles provided by another embodiment of the present application; Figure 7 is a cross-sectional schematic diagram of a scatterer provided by another embodiment of the present application; Figure 8 is a schematic diagram of a scatterer unit cell provided by another embodiment of the present application; Fig. 9 is a schematic diagram of the energy band structure of a scatterer provided by another embodiment of the present application; Fig.10 It is a comparison chart of the one-third octave band insertion loss obtained from the semi-anechoic chamber test provided by another embodiment of the present application and the test results of the sound barrier without the top reinforced noise reduction structure installed; Fig.11 is a comparison chart of the noise reduction effects of various types of sound barriers provided in another embodiment of the present application; The following are the descriptions of the reference numerals: 1. Screen body; 2. Bottom plate; 3-1. First side plate; 3-3. Second side plate; 4. Scatterer; 5. Microporous plate. DETAILED DESCRIPTION

[0017] The following will refer to the attached Figures 1 to 11The specific embodiments of the present application are described in detail. Although the specific embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0018] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the implementation of the present application, but the description is based on the general principles of the specification and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the attached claims.

[0019] To facilitate understanding of the embodiments of the present application, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the various drawings do not constitute a limitation on the embodiments of the present application.

[0020] Figure 3 , Figure 4 , Figure 5 and Figure 6 They are respectively a front view, a rear view, a side view and a top view of a sound barrier device based on Bragg scattering, cavity resonance and micropore principles provided by an exemplary embodiment of the present application, such as Figures 3 to 6 As shown, the device has a sound barrier top structure, which is used to enhance the noise reduction effect; The device comprises: Screen, The top structure of the screen body is provided with a supporting component and a sound wave scattering array component. The sound wave scattering array component is arranged based on the supporting component. The device is based on Bragg scattering, cavity resonance and micropore principles. Through the sound wave scattering array component, specific frequency components in the noise sound wave are controlled to reduce the sound energy of the noise sound wave.

[0021] The sound wave scattering array assembly described in this embodiment can fully cover all specific frequencies in the noise sound waves. Since the noise sound waves undergo Bragg scattering, cavity resonance, micropore sound absorption and reflection processes, each specific frequency can be dispersed based on the action of the sound wave scattering array assembly, thereby reducing the linear propagation and energy accumulation of the noise sound waves, thereby reducing the noise level and improving the acoustic quality of the environment.

[0022] It should be noted that the screen body is made of metal composite plate or concrete material.

[0023] Please refer to Figure 7 In another exemplary embodiment, the acoustic wave scattering array assembly comprises: A first scattering layer, a second scattering layer and a third scattering layer, wherein the first scattering layer, the second scattering layer and the third scattering layer constitute an asymmetric multi-layer structure.

[0024] In this embodiment, the sound wave scattering array component adopts a multi-layer structure, which can make the noise sound wave undergo Bragg scattering, cavity resonance, micropore sound absorption and reflection processes when passing through each layer. Each time the sound wave scattering array component interacts, the sound energy of the noise sound wave can be dispersed to varying degrees to reduce the directness of the sound wave, thereby effectively reducing the sound wave energy of the noise. In summary, the acoustic wave scattering array assembly can be optimized for a specific frequency range of noise sound waves, thereby covering a wider spectrum range and thereby improving the overall noise control performance.

[0025] In another exemplary embodiment, the first scattering layer includes a first scatterer, a second scatterer, and a third scatterer. In this embodiment, the first scatterer, the second scatterer and the third scatterer are all made of open PVC tubes. By vertically arranging the first scatterer, the second scatterer and the third scatterer with their openings facing the noise source to form the widest first scattering interface, the equivalent height of the sound barrier can be increased to increase the interaction opportunities between sound waves and scatterers, so that sound waves of different frequencies can enter the scatterers to the greatest extent in multiple directions, increasing the range of scattering, thereby reducing their penetration and perceptibility. In summary, the first scattering layer adopts a scattering layout with three scatterers forming the widest interface. This is the result of a deep understanding of the characteristics of increasing the equivalent height of the sound barrier and the interaction opportunities between sound waves and scatterers, and can preliminarily control and absorb noise.

[0026] In another exemplary embodiment, the second scattering layer includes a fourth scatterer and a fifth scatterer.

[0027] In this embodiment, by vertically arranging the openings of the fourth scatterer and the fifth scatterer toward the noise source to form a second scattering interface with a width smaller than that of the first scattering layer, the noise sound waves can be further dispersed and absorbed and the propagation direction can be changed when passing through the second scattering layer, thereby further reducing the sound wave energy and directionality of the noise sound waves.

[0028] In summary, the second scattering layer adopts a scattering layout with a wider interface composed of two scatterers. This is the result of a deep understanding of the characteristics of further dispersion and absorption of noise sound waves and change of propagation direction when passing through the second scattering layer. It can further consume sound wave energy and reduce the sound pressure behind the sound barrier.

[0029] In another exemplary embodiment, the third scattering layer includes a sixth scatterer.

[0030] In this embodiment, by using a separate scatterer as the third scattering layer, a third scattering interface with the narrowest width can be formed to form a gradient array with the first scattering layer and the second scattering layer, which can further reduce the residual sound wave energy.

[0031] In summary, the third scattering layer uses a separate scatterer to reduce the remaining transmitted noise sound waves. This is the result of a deep understanding of the characteristics of the periodic array structure. It can be organically combined with the first scattering layer and the second scattering layer to specifically control the noise sound waves.

[0032] It should be further explained that the scatterers in this application are all prepared based on the principle of phononic crystals. Phononic crystals are a periodic composite structure whose main feature is the ability to form band gaps for elastic waves. Within these band gap frequency ranges, phononic crystals can effectively suppress the propagation of elastic waves. Therefore, phononic crystals are particularly suitable for applications that require noise reduction within a specific frequency range. Band gaps are the key to the design of phononic crystals. These band gaps are caused by the periodic structure of the material. Its working principle is similar to that of photonic crystals. It affects the propagation path of sound waves in the material by structural periodic changes, thereby controlling the sound waves based on different principles.

[0033] The top noise-reinforced structure of the phononic crystal sound barrier has successfully overcome the three main defects of traditional sound barriers through its innovative design and significantly improved the overall noise reduction performance. This structure utilizes the characteristics of phononic crystals, that is, a band gap of elastic waves is formed through a specific periodic composite structure, thereby effectively suppressing the propagation of sound waves within a specific frequency range. This makes the noise reduction effect of the sound barrier more targeted and efficient, especially the band gap design customized for the main spectrum of road traffic noise, which can be optimized according to the specific noise characteristics of passing vehicles, thereby achieving more precise noise control. In addition, the variability of the design allows the sound barrier to better integrate with the surrounding traffic landscape, enhance the environmental beauty, and may enhance public acceptance and the overall perception of the landscape through artistic design.

[0034] In summary of the above-mentioned embodiments, the scattering layers with different scattering widths provided in the present application are implemented based on a full understanding of the diffraction and transmission paths of noise sound waves in the periodic array structure. This layered design uses complex sound wave paths and multi-level acoustic interactions, and effectively utilizes the mutual interference and diffraction phenomena between the frequency components of the noise sound waves to weaken the energy of the sound waves, thereby achieving more comprehensive and efficient noise control at multiple heights and directions.

[0035] Figure 8 FIG. 1 is a schematic diagram of a scatterer unit cell provided by another embodiment of the present application. Figure 8 As shown, the scatterer is made of PVC, whose acoustic impedance is much higher than that of air. When the sound wave propagates from the air matrix to the wall of the PVC scatterer, total reflection occurs and destructive interference occurs with the adjacent phononic crystals, thereby achieving a noise reduction effect at a specific frequency. At the same time, the scatterer has a resonant cavity. The noise sound wave enters the resonant cavity through the opening and generates heat energy by friction with the air in the cavity, thereby consuming sound energy. At the same time, the noise sound wave forms a resonant coupling with the noise sound wave reflected by the cavity wall in the cavity, which also plays a role in noise reduction. Figure 8 It can be seen that the scattering sound absorbers are arranged in a square lattice, and the lattice constant is a, which is 0.17m, that is, the horizontal and vertical center distances between adjacent scatterers are both a=0.17m.

[0036] In another exemplary embodiment, the first scattering layer, the second scattering layer and the third scattering layer are arranged in sequence along a propagation path of a noise source.

[0037] In this embodiment, since the first scattering layer contacts the incident sound wave first, it determines the equivalent height of the sound barrier and the interaction opportunity between the sound wave and the scatterer. Therefore, the first scattering layer needs the widest scattering interface. Furthermore, the second and third scattering layers are gradient-designed based on the sound wave diffraction and transmission path, and more comprehensive and efficient noise control is achieved through complex sound wave paths and multi-level acoustic interactions.

[0038] Based on the characteristics of each specific frequency in the noise sound wave, this embodiment first allows the noise sound wave to interact with the first scattering layer, effectively increasing the interaction opportunity between the noise sound wave and the scatterer, and further filters the specific frequency components through the second scattering layer and the third scattering layer.

[0039] In summary, the arrangement of the scattering layers described in this embodiment is designed based on the characteristics of noise sound waves and the characteristics of the periodic array structure. If the arrangement order is reversed, the noise control effect will be reduced, making it difficult for the top reinforced noise reduction barrier to exert its noise reduction performance advantages.

[0040] Please refer to Figure 7In another exemplary embodiment, microporous plates 5 are disposed in each of the first to sixth scatterers.

[0041] In this embodiment, when the noise sound wave passes through the microporous plate, the holes inside the microporous plate will cause the noise to be reflected and attenuated multiple times inside the plate. When the noise sound wave encounters an obstacle (such as a micropore) with a size comparable to or smaller than its wavelength during propagation, multiple reflections will occur. On the one hand, the reflection will cause the noise sound wave to deviate from the original straight propagation path and disperse in all directions, so that the energy of the noise sound wave can be dispersed rather than concentrated propagation, that is, a scattering effect occurs. On the other hand, it will make the propagation path of the noise sound wave longer, thereby weakening the sound energy in a specific direction, thereby reducing the direct impact on the receiving point.

[0042] In addition, the micropores on the microporous plate also have certain sound absorption properties, and can absorb component sound energy and convert it into heat energy or other forms of energy, thereby further reducing noise.

[0043] In another exemplary embodiment, the perforation rate of the microporous plate is 3%.

[0044] In this embodiment, the perforation rate refers to the percentage of the total area of ​​perforated holes in a specific area of ​​the material. For a micro-porous plate, the perforation rate is 3%, which means that the area covered by the perforated holes accounts for 3% of the total area of ​​the micro-porous plate, and the remaining 97% of the area is unperforated.

[0045] It should be noted that in this embodiment, the perforation rate of the microporous plate is set to 3% based on experimental verification. It has been verified that if the perforation rate is greater than 3%, more noise sound waves within the frequency range will pass through the microporous plate, thereby reducing the sound absorption efficiency of the microporous plate within a certain frequency range, especially for the medium and low frequency noise that needs to be controlled. At the same time, too many pores will reduce the air flow resistance and affect the control of airflow noise. In addition, if the perforation rate is too low (i.e., less than 3%), it will limit the flow of air through the micropores, thereby reducing the absorption and scattering ability of noise sound waves, especially for high-frequency noise. The control effect is not good, because high-frequency sound waves require smaller apertures and denser hole arrays for effective scattering. Therefore, this embodiment limits the perforation rate to 3%, which can achieve the best noise control effect.

[0046] In another exemplary embodiment, the supporting assembly includes a base plate, a first side plate and a second side plate, the base plate and the screen body are fixedly connected, and the first side plate and the second side plate extend along a vertical direction of the acoustic wave scattering array assembly to form a semi-enclosed space structure with the base plate.

[0047] In this embodiment, the bottom plate is made of metal plate, which mainly plays a supporting and fixing role for the sound wave scattering array assembly. The first side plate and the second side plate are made of metal plates. In addition to assisting the bottom plate in fixing the sound wave scattering array assembly, the first side plate and the second side plate also help to guide and control the flow path of noise sound waves. Through the guidance of the first side plate and the second side plate, the propagation of noise sound waves around and inside the scatterer will be more complicated. Specifically, the setting of the side plate provides additional reflection surfaces for noise sound waves. When the noise sound waves contact the side plates, reflection, refraction and interference phenomena will occur. These reflected waves will interact with the original sound waves and the waves reflected from other scatterers to form complex wavefront interlacing, causing the sound field to become chaotic, thereby enhancing the scattering effect.

[0048] In addition, the guiding effect of the side panels makes the noise waves no longer propagate in a straight line, but are forced to travel along a more tortuous path, which increases the propagation distance and time of the noise waves, and also increases the chance of the noise waves contacting the scatterers. Each additional contact can cause a new scattering, thereby further decomposing the noise wave energy.

[0049] In another exemplary embodiment, the first side plate is provided with a first hole structure, the second side plate is provided with a second hole structure symmetrical to the first hole structure, and the first hole structure and the second hole structure correspond to the first scattering layer, the second scattering layer and the third scattering layer.

[0050] In this embodiment, holes are provided in the first side panel and the second side panel for the purpose of fixing the first to sixth scatterers and enabling the noise sound waves to have more complex interactions between the scatterers and the side panels. The noise sound waves around the scatterers can pass through the holes from the inside of the side panel to the outside of the side panel, and then be reflected or scattered again, thereby increasing the diversity of the propagation paths of the noise sound waves, and thus further weakening the sound wave energy of the noise. In addition, in outdoor environments, the holes can also help balance the difference in internal and external air pressure caused by wind pressure or temperature changes, avoiding damage to the structure due to excessive internal and external pressure differences, while also reducing the generation of wind noise.

[0051] Fig. 9 Schematic diagram of the energy band structure of a scatterer provided by another embodiment of the present application. The peak of highway noise is mainly concentrated at 500 and 1000 Hz. Fig. 9It can be seen that the resonance and Bragg complete band gap ranges of the designed example structure are 422.33-704.36 Hz and 1017.9-1403.6 Hz (dark band area), respectively. There are also multiple directional band gaps (light band area), covering the peak frequency band of the highway. Since the noise reduction device described in this application has the characteristics of wideband and multi-band, the noise sound waves will not be able to continue to propagate in the forbidden band, making the noise reduction more targeted while taking into account the noise reduction performance of the entire frequency band.

[0052] Fig.10 This is a comparison chart of the one-third octave band insertion loss obtained from the semi-anechoic chamber test provided by another embodiment of the present application and the test results of the sound barrier without the top reinforced noise reduction structure installed. Fig.10 It can be seen that the noise reduction device described in this application has a certain improvement effect on the overall noise reduction effect in the main noise frequency band of 315-2500Hz highways compared with the traditional T-shaped sound barrier, and the average noise reduction amount is increased by about 4.3dB (A). The noise reduction effect is more obvious within the designed band gap range, which is verified by the energy band structure. Within the resonant band gap range, the average noise reduction effect is improved by about 3.25 dB, and within the Bragg band gap range, the average noise reduction effect is improved by about 6.34dB; after filling the micro-perforated plate, the noise reduction effect near 800Hz and 2000Hz is improved by 1~2dB.

[0053] Fig.11 FIG. 1 is a schematic diagram comparing the noise reduction effects of various types of sound barriers provided by another embodiment of the present application. Fig.11 It can be seen that the noise reduction device described in the present application has great advantages over the existing noise reduction devices in the entire frequency band. In the main noise frequency band of highways above 315Hz, the designed top reinforced noise reduction barrier has a noise reduction effect of about 3.6dB higher than that of traditional T-shaped and lightweight concrete sound barriers, about 4.6dB higher than that of metal composite plate sound barriers, and about 6.4dB higher than that of open phononic crystal sound barriers.

[0054] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A sound barrier device based on Bragg scattering, cavity resonance and micropore principles, characterized in that: The device has a sound barrier top structure, and the top structure is used to enhance the noise reduction effect; The device comprises: Screen, The top structure of the screen body is provided with a support component and a sound wave scattering array component, wherein: The acoustic wave scattering array assembly is arranged based on the supporting assembly, The device is based on the principles of Bragg scattering, cavity resonance and micropores, and scatters different frequency components in noise sound waves through the sound wave scattering array component to reduce the sound energy of the noise sound waves.

2. The device according to claim 1, characterized in that Preferably, the acoustic wave scattering array assembly comprises: A first scattering layer, a second scattering layer and a third scattering layer.

3. The device according to claim 2, characterized in that The first scattering layer comprises: a first scatterer, a second scatterer and a third scatterer, The first scatterer, the second scatterer and the third scatterer constitute a first scattering interface.

4. The device according to claim 3, characterized in that The second scattering layer comprises: The fourth scatterer and the fifth scatterer, The fourth scatterer and the fifth scatterer form a second scattering interface.

5. The device according to claim 4, characterized in that The third scattering layer comprises: The sixth scatterer, The sixth scatterer constitutes a third scattering interface.

6. The device according to claim 5, characterized in that The first scattering layer, the second scattering layer and the third scattering layer are arranged in sequence along a propagation path of a noise source.

7. The device according to claim 5, characterized in that Microporous plates are disposed in the first to sixth scatterers.

8. The device according to claim 7, characterized in that The perforation rate of the microporous plate is 3%.

9. The device according to claim 1, characterized in that The support assembly includes a bottom plate, a first side plate and a second side plate.

10. The device according to claim 9, characterized in that The first side plate is provided with a first hole structure, and the second side plate is provided with a second hole structure.

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