CN110783084A - A broadband composite resonance sound absorption and isolation structure - Google Patents

Abstract

The invention discloses a broadband composite resonance sound absorption and insulation structure which comprises a micro-perforated cover plate, a porous sound absorber A, a middle-layer free plate, a porous sound absorber B, a side wall plate and a bottom plate, wherein the micro-perforated cover plate and the bottom plate are arranged in parallel, the micro-perforated cover plate and the bottom plate are connected through the side wall plate to form a resonance cavity, the resonance cavity is filled with the porous sound absorber, the middle-layer free plate is positioned between two different porous sound absorbers and arranged in parallel with the bottom plate, and the broadband composite resonance sound absorption and insulation structure further comprises a damping coating layer which is coated on the bottom plate and arranged on one side far away from the resonance cavity.

Description

A broadband composite resonance sound absorption and isolation structure

technical field

The invention relates to the technical field of environmental engineering, in particular to a broadband composite resonance sound absorption and insulation structure.

Background technique

The resonant sound-absorbing structure is mainly a Helmholtz resonator structure, which generates resonance inside the structure through sound waves to achieve the purpose of consuming sound energy. The frequency change of the incident sound wave will affect the sound absorption coefficient of the resonant structure. When the frequency of the incident sound wave is at the resonance frequency of the system, the sound absorption performance is the best. The resonance sound absorption structure mainly includes three types of perforated plate resonance sound absorption, film/thin plate resonance sound absorption and micro-perforated plate resonance sound absorption structure. Among them, the film and thin plate resonance structure only introduces the resonance absorption of the cavity behind the plate, and generally only has a better sound absorption effect in a very small frequency range near the resonance frequency, so its effective sound absorption frequency band is generally very narrow, usually only used for Noise reduction for specific frequency noise.

The diameter of the traditional perforated plate resonance absorption structure is generally in the order of millimeters or even centimeters, so the sound resistance is small, the sound quality is large, the sound absorption frequency band is narrow, and the frequency selectivity is strong. The sound absorption performance is deviated from the resonance frequency, and the sound absorption effect is obviously deteriorated. One way to widen the effective sound absorption bandwidth of the single-layer micro-perforated plate sound-absorbing body is to use a multi-layer composite micro-perforated plate sound-absorbing structure, but the multi-layer composite structure obviously increases the complexity of the structure, and also increases the material and The cost is also limited by the spatial distance in practical engineering applications. Another method is to place sound absorbing material on the back of the microperforated plate, but the effect of low frequency improvement is limited. Then there is the further reduction of the perforation diameter. According to Mr. Ma Dayou's theory, when the perforation diameter of the micro-perforated plate is less than 0.1 mm, it is expected to reach the frequency band limit of the micro-perforated plate sound absorber. However, traditional machining methods cannot realize the processing of ultra-micro-hole aperture micro-perforated plates. Other processing methods, such as laser drilling, will greatly increase the production cost due to the increase of punching density, which is not suitable for mass production.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and to provide a wide-band composite resonance sound-absorbing and insulating structure with sound absorption frequency bandwidth, light weight and good low-frequency effect.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

A broadband composite resonance sound absorption and sound insulation structure, comprising a micro-perforated cover plate, a porous sound-absorbing body A, a middle-layer free plate, a porous sound-absorbing body B, a side wall plate and a bottom plate, wherein the micro-perforated cover plate and the bottom plate are arranged in parallel and The micro-perforated cover plate and the bottom plate are connected by side wall plates to form a resonance cavity, the resonance cavity is filled with a porous sound absorbing body A and a porous sound absorbing body B, and the middle layer free plate is located between the porous sound absorbing body A and the porous sound absorbing body B. The sound absorbing bodies B are arranged parallel to the bottom plate. The broadband composite resonance sound absorbing and insulating structure further includes a damping paint layer, and the damping paint layer is coated on the bottom plate and disposed on one side away from the resonance cavity.

As a further improvement to the above technical solution:

The thickness of the damping paint layer is d1, and the thickness of the bottom plate is d2, where d1:d2=1-3.

The middle layer free plate and the side wall plate vibrate freely.

The perforation diameter D of the micro-perforated cover plate is less than or equal to 1 mm, and the perforation porosity is 1% to 10%.

The micro-perforated cover plate is an aluminum plate or a steel plate.

The porous sound-absorbing material is one of polyurethane foam, microporous ceramics, glass wool, and foamed aluminum.

The bottom plate is a steel plate.

The thickness of the micro-perforated cover plate is 0.5-2 mm; the thickness of the porous sound absorbing body A and the porous sound absorbing body B is 10-40 mm; the thickness of the middle-layer free plate is 0.5-2 mm; the thickness of the bottom plate 1mm to 3mm.

Compared with the prior art, the advantages of the present invention are:

The broadband composite resonance sound absorption and sound insulation structure of the present invention adopts a micro-perforated cover plate (aperture D≤1mm). According to Mr. Ma Dayou's theory, the sound absorption frequency band is wider and the sound absorption effect is better; the resonance cavity is filled with two different Porous sound absorbing body, the thickness of each porous sound absorbing body is determined according to the relationship between the quality of the mass spring resonance structure and the vibration, to further optimize the sound absorption frequency band bandwidth; the damping coating layer is coated on the bottom plate and is arranged on the side away from the resonance cavity, which can It improves the sound insulation performance very well. Sound waves enter from the micro-perforated cover plate. When a small amount of sound waves exits from the bottom plate, the damping coating layer on the outside of the bottom plate reflects the sound waves into the resonant cavity again, which further increases the loss of sound waves and reduces reflection. sonic energy. The broadband composite resonance sound absorption and sound insulation structure of the invention has good sound absorption frequency bandwidth, low frequency effect, light weight, high efficiency, low cost and environmental protection, and is suitable for sound insulation and noise reduction of power equipment, such as sound insulation barriers for transformers or reactors.

Description of drawings

FIG. 1 is a schematic structural diagram of a broadband composite resonance sound absorbing and insulating structure of the present invention.

The symbols in the figure represent: 1. Micro-perforated cover plate; 2. Porous sound-absorbing body A; 3. Middle layer free plate; 4. Porous sound-absorbing body B; 5. Side wall plate; 6. Bottom plate; 7. Damping paint layer .

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the instruments or materials used in the present invention are commercially available.

Example 1:

As shown in FIG. 1 , a broadband composite resonance sound absorbing and insulating structure of this embodiment includes: a micro-perforated cover plate 1 , a porous sound absorbing body A 2 , a middle-layer free plate 3 , a porous sound absorbing body B 4 , a side wall The plate 5 and the bottom plate 6, the micro-perforated cover plate 1 and the bottom plate 6 are arranged in parallel, and the micro-perforated cover plate 1 and the bottom plate 6 are connected by the side wall plate 5 to form a resonance cavity, and the resonance cavity is filled with the porous sound absorber A 2 and the bottom plate 6. Porous sound absorbing body B 4, the middle layer free plate 3 is located between the porous sound absorbing body A 2 and the porous sound absorbing body B 4 and is arranged in parallel with the bottom plate 6, and the porous sound absorbing body A 2 and the porous sound absorbing body B 4 use different Made of porous sound absorbing material, the broadband composite resonance sound absorbing and insulating structure further includes a damping paint layer 7, which is coated on the bottom plate 6 and is disposed on the side away from the resonance cavity. .

The thickness of the damping paint layer 7 is d1, and the thickness of the bottom plate 6 is d2, where d1:d2=1-3, and the damping sound insulation effect is the best among the thickness ratios.

The middle layer free plate 3 and the side wall plate 4 are not connected, and both vibrate freely. The middle-layer free plate 3 adopts a free structure, which can greatly improve the low-frequency sound absorption performance. The specific thickness and material selection of the middle-layer free plate 3, and the material and thickness of the porous sound absorbing body should be determined according to the relationship between the quality of the mass spring resonance structure and the vibration. , the sound absorption frequency band can be very wide, and further optimize according to the test results to achieve the best performance. In this embodiment, the micro-perforated cover plate 1 is a steel plate with a thickness of 1 mm, and the micro-sound absorption holes on the micro-perforated cover plate 1 are round holes with a diameter of 0.5 mm and a porosity of 5%; the middle-layer free plate 3 is a steel plate with a thickness of 5%. 1mm; bottom plate 6 is 2mm steel plate, damping paint layer 7 is 4mm thick; porous sound absorber A 2 is polyurethane foam with a thickness of 40mm; porous sound absorber B 4 is foamed aluminum with a thickness of 40mm.

In this embodiment, the damping coefficient of the damping paint layer 7 is better than 0.4 in the middle and low frequency bands.

In other embodiments, the micro sound-absorbing holes on the micro-perforated cover plate 1 can also achieve the same or similar technical effects by adopting square holes.

In other embodiments, the porous sound absorbing materials of the porous sound absorbing body A 2 and the porous sound absorbing body B 4 respectively adopt microporous ceramics or glass wool to achieve the same or similar technical effects.

In other embodiments, the thickness of the micro-perforated cover plate 1 is 0.5-2 mm, the thickness of the porous sound absorbing body A2 or the porous sound absorbing body B4 is 10-40 mm, the thickness of the middle-layer free plate 3 is 0.5-2 mm, and the thickness of the bottom plate 5 is 0.5-2 mm. The thickness is 1mm to 3mm, and the same or similar technical effects can be achieved.

In other embodiments, the same or similar technical effects can be achieved when the perforation diameter D of the micro-perforated cover plate 1 is less than or equal to 1 mm, and the perforation porosity is 1% to 10%. The perforation diameter D≤1mm, which has better sound absorption effect compared with large holes.

Example 2:

The broadband composite resonance sound absorbing and insulating structure of this embodiment is roughly the same as that of Embodiment 1, except that the micro-perforated cover plate 1 is an aluminum plate, and the middle-layer free plate 3 is an aluminum plate.

Example 3:

The broadband composite resonance sound absorption and sound insulation structure of this embodiment is roughly the same as that of Embodiment 1, except that the micro-perforated cover plate 1 is an aluminum plate, and the middle-layer free plate 3 is a steel plate.

The following table shows the test results of the sound absorption properties of the three samples at specific frequencies.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above, or modify it into an equivalent implementation of equivalent changes. example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention should fall within the protection scope of the technical solutions of the present invention.

Claims (8)

1. The utility model provides a sound insulation structure is inhaled in broadband composite resonance which characterized in that: comprises a micro-perforated cover plate (1), a porous sound absorber A (2), a middle free plate (3), a porous sound absorber B (4), a side wall plate (5) and a bottom plate (6), the micro-perforated cover plate (1) and the bottom plate (6) are arranged in parallel, the micro-perforated cover plate (1) and the bottom plate (6) are connected through the side wall plate (5) to form a resonance cavity, the resonant cavity body is filled with a porous sound absorber A (2) and a porous sound absorber B (4), the middle free plate (3) is positioned between the porous sound absorber A (2) and the porous sound absorber B (4) and is arranged in parallel with the bottom plate (6), the porous sound absorption material A (2) and the porous sound absorption body B (4) are made of different porous sound absorption materials, the broadband composite resonance sound absorption and insulation structure further comprises a damping coating layer (7), and the damping coating layer (7) is coated on the bottom plate (6) and is arranged on one side far away from the resonance cavity.

2. The broadband composite resonance sound absorption and insulation structure according to claim 1, characterized in that: the thickness of the damping paint layer (7) is d1, the thickness of the bottom plate (6) is d2, and d1 to d2 are 1-3.

3. The broadband composite resonance sound absorption and insulation structure according to claim 2, characterized in that: the middle layer free plate (3) and the side wall plate (5) vibrate freely.

4. The broadband composite resonance sound absorption and insulation structure according to claim 2, characterized in that: the aperture D of the perforation on the micro-perforation cover plate (1) is less than or equal to 1mm, and the perforation porosity is 1-10%.

5. The broadband composite resonance sound absorption and insulation structure according to any one of claims 1 to 3, characterized in that: the micro-perforated cover plate (1) is an aluminum plate or a steel plate.

6. The broadband composite resonance sound absorption and insulation structure according to any one of claims 1 to 3, characterized in that: the porous sound absorption material is one of polyurethane foam, microporous ceramic, glass wool and foamed aluminum.

7. The broadband composite resonance sound absorption and insulation structure according to any one of claims 1 to 3, characterized in that: the bottom plate (6) is a steel plate.

8. The broadband composite resonance sound absorption and insulation structure according to any one of claims 1 to 3, characterized in that: the thickness of the micro-perforated cover plate (1) is 0.5-2 mm; the thickness of the porous sound absorber A (2) and the thickness of the porous sound absorber B (4) are 10-40 mm; the thickness of the middle free plate (3) is 0.5-2 mm; the thickness of the bottom plate (6) is 1-3 mm.

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