Multi-layer stacked impedance silencing plate for sound barrier

Abstract

The invention provides an impedance silencing plate for a sound barrier capable of being combined and stacked in multiple layers, which comprises a sound facing surface, a sound backing surface and a plurality of impedance silencing units arranged between the sound facing surface and the sound backing surface, and each impedance silencing unit is a variable cross-section cavity which sequentially extends and penetrates from the sound facing surface to the sound backing surface. A plurality of rows of impedance noise elimination units are arranged on the noise elimination plate, noise is eliminated when passing through the impedance noise elimination units, the purpose of noise elimination and reduction is achieved, and experimental tests prove that the noise reduction coefficient of the impedance noise elimination plate reaches 0.95-1.0. According to the impedance silencing plate, the multiple layers of plates are stacked and combined into the impedance silencing plate, the manufacturing difficulty of the impedance silencing unit is reduced, the manufacturing efficiency of the impedance silencing plate is greatly improved, and the impedance silencing plate is wide in material source, easy to obtain, low in manufacturing cost, light in product weight, good in mechanical strength and fatigue resistance and high in application and popularization value.

Description

Technical Field

[0001] This invention relates to a noise protection device, and more particularly to a multi-layer stacked impedance sound-absorbing plate for a sound barrier. Background Technology

[0002] Sound barriers, also known as noise walls, are structures placed between a sound source and a receiver to significantly attenuate sound wave propagation, thereby reducing noise pollution in a defined area. They are primarily used for noise reduction on highways, expressways, elevated roads, and other noise sources. Sound barriers are categorized into purely sound-insulating reflective barriers and composite barriers that combine sound absorption and insulation; the latter is considered a more effective method. Highways and expressways are where all types of sound barriers are most commonly used.

[0003] Sound barriers can generally be classified into vertical sound barriers and fully enclosed sound barriers according to their structural form. Vertical sound barriers typically consist of steel profiles and barrier panels positioned between adjacent steel profiles. These barrier panels can be divided into metal panels and non-metal panels, with non-metal panels further divided into transparent panels and cement-based panels. Existing cement-based panels are generally hollow slab structures cast from cement concrete. Their characteristics include heavy weight, poor sound absorption, and a tendency to crack over time. Therefore, providing a non-metallic sound barrier with good sound absorption and resistance to cracking is a technical problem that needs to be solved in the industry. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a multi-layer stacked impedance sound-absorbing plate for sound barriers.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: A multi-layer stacked impedance silencing plate for a sound barrier includes a frontal surface, a backal surface, and several impedance silencing units disposed between the frontal surface and the backal surface. Each impedance silencing unit is a variable cross-section cavity that extends sequentially from the frontal surface to the backal surface.

[0006] The variable cross-section cavity, from the front sound surface to the back sound surface, includes an opening, a gradually expanding sound-absorbing structure one, a cylindrical channel one, a gradually expanding sound-absorbing structure two, and several cylindrical channels two.

[0007] The opening is a horn-shaped opening, and the opening of the horn-shaped opening faces the frontal surface.

[0008] The gradually expanding sound-absorbing structure is a frustum-shaped structure with an increasing diameter.

[0009] The extension line of the second cylindrical channel does not intersect with the extension line of the first cylindrical channel.

[0010] The cylindrical channel has an annular cavity inside, and the cross-section of the annular cavity is larger than the cross-section of the cylindrical channel.

[0011] The cylindrical channel can be selected as a cylindrical cavity, a square cylindrical cavity, a polygonal cylindrical cavity, or a triangular cylindrical cavity.

[0012] The impedance silencing plate is composed of several non-metallic plates stacked together. Different cavities of different shapes are respectively provided at corresponding positions on the non-metallic plates, and the sub-cavities are combined to form a variable cross-section cavity.

[0013] The non-metallic board is a cement board, cement fiberboard, perforated board, or PVC board.

[0014] The non-metallic plate is formed by pressing with a mold, and the mold is provided with protrusions that match the shape of the sub-cavity.

[0015] The beneficial effects of this invention are as follows: The multi-layer stacked impedance silencing plate for sound barriers provided by this invention reduces noise as it passes through multiple impedance silencing units on the silencing plate, achieving the purpose of noise reduction. Experimental tests have shown that the noise reduction coefficient of this impedance silencing plate reaches 0.95~1.0. This invention uses multi-layer boards stacked together to form an impedance silencing plate. The multi-layer stacked combination manufacturing method reduces the manufacturing difficulty of the impedance silencing units and greatly improves the manufacturing efficiency of the impedance silencing plate. Moreover, the materials of this product are widely available and easy to obtain, the manufacturing cost is low, the product is lightweight, and it has good mechanical strength and fatigue resistance, making it of great value for promotion and application. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of a sound barrier using the impedance silencing plate of the present invention; Figure 2 This is a schematic diagram of the exploded structure of an impedance silencing plate. Figure 3 This is a schematic diagram of the cross-sectional structure of the impedance silencing plate; Figure 4 for Figure 3 Enlarged view of the cross-sectional structure; Figure 5 This is a schematic diagram of the sound-absorbing unit. Figure 6 The diagram shows two structural forms of the cross-section of the noise reduction unit. Detailed Implementation

[0017] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0018] like Figure 1 , 2As shown in Figures 3 and 4, this invention provides a multi-layered stacked impedance silencing panel for sound barriers, comprising a frontal surface, a backal surface, and several impedance silencing units disposed between the frontal and backal surfaces. Each impedance silencing unit is a variable cross-section silencing cavity extending through the frontal and backal surfaces. The impedance silencing units are arranged in several rows, with several units per row according to the ratio of the impedance silencing panel to the number of impedance silencing units. Figure 2 , 3 As shown in Figures 4 and 5, the variable cross-section silencing cavity extends from the front to the back of the sound-absorbing surface. It includes, in sequence, an opening 1, a gradually expanding silencing structure 1 2, a cylindrical channel 1 3, a gradually expanding silencing structure 2 4, and several cylindrical channels 2 5. In order to better concentrate the noise sound waves into the impedance silencing unit, the opening 1 is set as a horn mouth, with the opening facing the front of the sound-absorbing surface. The horn mouth is larger on the outside and smaller on the inside. This structure has the effect of converging sound waves and maximizing the sound wave incidence. The inner surface of the horn mouth can be set as a wedge shape, terrace shape, or other non-smooth planar shape, in order to increase the sound wave reflection surface and quickly dissipate the sound waves. After the sound wave passes through the smallest diameter of the horn opening, it enters the gradually expanding silencing structure 2. The gradually expanding silencing structure 2 is connected at the smallest diameter of the horn opening. The gradually expanding silencing structure 2 is a frustum-shaped structure with a diameter that gradually increases. Along the direction of sound wave propagation, the cavity inside gradually increases until it reaches its maximum diameter. At this point, the sound wave encounters the cylindrical channel 3, which is connected at the maximum diameter of the gradually expanding silencing structure 2. The diameter of the cylindrical channel 3 is much smaller than the maximum diameter of the gradually expanding silencing structure 2, approximately between 1 / 2 and 1 / 4 of the maximum diameter. When the sound wave encounters the abrupt change in the diameter of the cross-section, the cross-sectional impedance is high, which causes impedance mismatch and thus reduces noise. Experiments have shown that the noise reduction effect is best when the diameter of the cylindrical channel 3 is between 1 / 3 and 3 / 10 of the maximum diameter of the gradually expanding silencing structure 2.

[0019] To further enhance the noise reduction effect, an annular cavity 31 is provided in the middle of the cylindrical channel 3. The annular cavity 31 is connected to the cylindrical channel 3, and its cross-section is larger than that of the cylindrical channel 3. When sound waves enter the annular cavity 31 along the cylindrical channel 3, the air column at the entrance of the annular cavity 31 and the air column inside the annular cavity 31 form a gas resonance system. When the noise frequency is equal to the natural frequency of this gas resonance system, a resonance effect will occur. During resonance, the air and the inner wall generate intense friction, and the sound energy is consumed by overcoming the frictional resistance, thereby reducing the noise. Figure 3 , 4 As shown in Figure 5, the annular cavity 31 can be configured as a cylindrical or irregular cylindrical shape. The length of the annular cavity 31 can be close to the length of the cylindrical channel 3, which can maximize the capacity to contain, absorb, and weaken noise. It has been verified that this structure is mainly used to reduce low-frequency noise.

[0020] Following cylindrical channel 3 is a gradually expanding silencing structure 4. Sound waves enter the gradually expanding silencing structure 4 through the opening of cylindrical channel 3. The inner diameter gradually increases and the impedance gradually decreases. When the sound waves encounter the cross-sections of several cylindrical channels 5 again, since the extension lines of these cylindrical channels 5 do not intersect with the extension lines of cylindrical channel 3, the sound waves avoid direct passage through the silencing unit when they encounter the cross-sections. The sound wave impedance suddenly increases, further weakening the noise.

[0021] As a specific option, the cavities of cylindrical channel 1 3 and cylindrical channel 2 5 can be cylindrical cavities, square cylindrical cavities, polygonal cylindrical cavities, or triangular cylindrical cavities.

[0022] To facilitate manufacturing and simplify the process, the impedance-absorbing soundproofing panel is composed of several non-metallic plates stacked together. Different shaped sub-cavities are set at corresponding positions on each non-metallic plate, and the corresponding sub-cavities on each layer combine to form a variable cross-section cavity. Specifically, the non-metallic plates are cement fiberboard or PVC-U board. The non-metallic plates are molded using a mold with protrusions whose shapes match the shapes of the sub-cavities. This stacked structure breaks away from the conventional approach of one-piece casting or extrusion molding of sound barrier unit panels. By using a multi-plate stacking method, it saves costs and reduces manufacturing complexity, making it suitable for large-scale application.

[0023] Because the aforementioned sound barrier uses a multi-layered impedance silencing plate with silencing holes, and the front and back of the silencing plate are interconnected, the airflow balance between the front and back of the silencing plate can be guaranteed. Therefore, this silencing plate can replace the existing louvered sound barrier plate or load-reducing sound barrier plate with ventilation function.

[0024] The embodiments described above are merely one preferred embodiment of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-layer stacked impedance silencing panel for a sound barrier, comprising a frontal surface, a backal surface, and a plurality of impedance silencing units disposed between the frontal surface and the backal surface, characterized in that, The impedance silencing unit is a variable cross-section cavity that extends sequentially from the front surface to the back surface.

2. The multi-layer stacked impedance anechoic panel for sound barriers according to claim 1, characterized in that, The variable cross-section cavity, from the front sound surface to the back sound surface, includes an opening, a gradually expanding sound-absorbing structure one, a cylindrical channel one, a gradually expanding sound-absorbing structure two, and several cylindrical channels two.

3. The multi-layer stacked impedance sound-absorbing panel for sound barriers according to claim 2, characterized in that, The opening is a horn-shaped opening, and the opening of the horn-shaped opening faces the frontal surface.

4. The multi-layer stacked impedance anechoic panel for sound barriers according to claim 2, characterized in that, The gradually expanding sound-absorbing structure is a frustum-shaped structure with an increasing diameter.

5. The multi-layer stacked impedance anechoic panel for sound barriers according to claim 2, characterized in that, The extension line of the second cylindrical channel does not intersect with the extension line of the first cylindrical channel.

6. The multi-layer stacked impedance anechoic panel for sound barriers according to claim 2, characterized in that, The cylindrical channel is provided with an annular cavity, the cross-section of which is larger than the cross-section of the cylindrical channel.

7. The multi-layer stacked impedance sound-absorbing panel for sound barriers according to claim 2, characterized in that, The cylindrical channel one or cylindrical channel two can be selected as a cylindrical cavity, a square cylindrical cavity, a polygonal cylindrical cavity, or a triangular cylindrical cavity.

8. The multi-layer stacked impedance anechoic panel for sound barriers according to claim 1, characterized in that, The impedance silencing plate is composed of several non-metallic plates stacked together. Different cavities of different shapes are respectively provided at corresponding positions on the non-metallic plates, and the sub-cavities are combined to form the variable cross-section cavity.

9. The multi-layer stacked impedance sound-absorbing panel for sound barriers according to claim 8, characterized in that, The non-metallic board is a cement board, cement fiberboard, perforated board, or PVC board.

10. The multi-layer stacked impedance anechoic panel for sound barriers according to claim 8, characterized in that, The non-metallic plate is formed by pressing with a mold, and the mold is provided with protrusions that match the shape of the sub-cavity.

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