CN116005830A - An acoustic barrier for an anechoic chamber - Google Patents

Abstract

The invention provides an acoustic barrier of a sound elimination chamber, which comprises a mechanical bearing structure, an acoustic wedge assembly, a longitudinal composite sound absorption layer, two perforated plates and a plurality of transverse composite sound absorption layers, wherein the acoustic wedge assembly is positioned at the inner side of the mechanical bearing structure; the two perforated plates are separated into a plurality of silencing cavities by a transverse composite sound absorbing layer, and one perforated plate is connected with the longitudinal composite sound absorbing layer. The sound barrier for the anechoic chamber provided by the invention has a double sound attenuation mechanism of porous sound attenuation and local resonance sound attenuation, and well blocks sound waves in different frequency ranges respectively for medium-high frequency waves and low frequency waves, so that the incident sound waves are attenuated and blocked, the sound absorption and insulation performance of a better broadband is ensured, the structure quality is small, the thickness limit is less, and the sound environment is conveniently and rapidly constructed in a prefabricated member splicing mode, thereby effectively reducing the production and installation cost.

Description

An acoustic barrier for an anechoic chamber

technical field

The invention relates to the technical field of acoustic barriers, in particular to an acoustic barrier for an anechoic chamber.

Background technique

The anechoic chamber is a common acoustic test environment. Since the anechoic chamber needs to block the sound waves entering the anechoic chamber from the outside world, it also needs to absorb and dissipate the sound waves emitted in the test environment to prevent its reflection from entering the acoustic chamber again. test environment. And this function is usually completed by the acoustic barrier. At this stage, the more common acoustic barriers for anechoic chambers usually include metal plate sandwich-pike structures and concrete-pike structures. The former is usually used in occasions that require frequent movement, such as doors and windows in anechoic chambers, while the latter is mainly used for noise reduction. Room walls and other non-moving places. Both of them usually block the sound waves entering the room from the outside through the sound insulation effect formed by their relatively large equivalent density, and at the same time absorb and dissipate the sound waves emitted in the test environment through wedges.

Due to the complexity of the surrounding environment of the anechoic chamber, subject to the law of acoustic quality, this type of sound insulation structure has good barrier properties for medium and high frequency sound waves, and for low frequency waves with longer wavelength characteristics, it is necessary to increase the thickness of the structure to ensure good performance. sound insulation performance. This will also lead to a series of problems such as large mass, large volume, and inconvenient movement of traditional acoustic barriers.

Contents of the invention

The object of the present invention is to disclose an acoustic barrier for an anechoic chamber, which has a double silencing mechanism of porous silencing and local resonance silencing. Attenuation and isolation, while ensuring good broadband sound absorption performance, the structural mass is small, the thickness limit is small, and it is convenient to quickly build the acoustic environment through the splicing of prefabricated parts, thus effectively reducing production and installation costs. In addition, the structural parameters can be adjusted according to the sound wave characteristics that need to be blocked, and the sound attenuation performance of the acoustic barrier with established parameters can also be calculated.

To achieve the above object, the present invention provides an acoustic barrier for an anechoic chamber, which includes a mechanical bearing structure, an acoustic wedge assembly located inside the mechanical bearing structure, a longitudinal composite sound-absorbing layer located outside the mechanical bearing structure, and two perforated plates , a number of horizontal composite sound-absorbing layers connected between two perforated panels; the two perforated panels are divided into several sound-absorbing cavities by a horizontal composite sound-absorbing layer, one of which is a perforated panel and a longitudinal composite sound-absorbing layer connection; the perforated plate is composed of several sub-plates, the sub-plate is provided with several perforations, and the sub-plate is also provided with a strip-shaped opening, and the strip-shaped opening extends N weeks around the sub-plate, and the strip A resonance area is formed inside the strip-shaped opening, a frame area is formed outside the strip-shaped opening, and an elastic area is formed in the strip-shaped opening area.

In some embodiments, the N is greater than 1.

In some embodiments, the elastic region is a region surrounded by adjacent sides of the strip-shaped opening.

In some embodiments, the strip-shaped opening extends in a zigzag shape or in a mosquito coil shape.

In some embodiments, the sub-boards are arranged on the outer wall and the inner wall of the muffler cavity.

In some embodiments, several sub-boards are integrally constructed.

In some embodiments, the perforations are uniformly distributed on the sub-board.

In some embodiments, the composite sound-absorbing layer is composed of multiple layers of porous sound-absorbing materials with different damping properties.

In some embodiments, the mechanical bearing structure is a mounting base.

In some embodiments, the acoustic wedge assembly is a metal plate sandwich wedge structure and a concrete wedge structure.

Compared with the prior art, the beneficial effects of the present invention are: the acoustic barrier of the anechoic chamber provided by the present invention has a dual silencing mechanism of porous silencing and local resonance silencing, which can better block the middle and high frequency waves and low frequency waves respectively. Sound waves in different frequency ranges attenuate and block incident sound waves. While ensuring good broadband sound absorption and insulation performance, the structural quality is small and the thickness limit is small, and it is convenient to quickly monitor the acoustic environment through prefabricated parts splicing. In addition, the structural parameters can be adjusted according to the sound wave characteristics that need to be blocked, and the sound attenuation performance of the acoustic barrier with the specified parameters can also be calculated.

Description of drawings

Fig. 1 is the structural representation of a kind of anechoic room acoustic barrier shown in the present invention;

Fig. 2 is the enlarged view of label A in Fig. 1;

Fig. 3 is a B-direction view of the sub-board shown in Fig. 2;

Figure 4 is the equivalent dynamic model and calculation model diagram of local resonance sound insulation.

Detailed ways

The present invention will be described in detail below in conjunction with the implementations shown in the drawings, but it should be noted that these implementations are not limitations of the present invention, and those of ordinary skill in the art based on the functions, methods, or structural changes made by these implementations Equivalent transformations or substitutions all fall within the protection scope of the present invention.

An acoustic barrier for an anechoic room as shown in FIGS. 1-3 includes a mechanical bearing structure 1 and an acoustic wedge assembly 2 located inside the mechanical bearing structure 1 .

The mechanical bearing structure 1 plays the role of supporting the acoustic barrier, the mechanical bearing structure 1 is an installation base, and the acoustic wedge assembly 2 is installed on the installation base. The acoustic wedge assembly 2 deflects and absorbs the incident sound waves inside the barrier. The acoustic wedge assembly 2 is a metal plate sandwich wedge structure and a concrete wedge structure.

A longitudinal composite sound-absorbing layer 3 located outside the mechanical bearing structure 1 , two perforated plates 5 , and several transverse composite sound-absorbing layers 3 connected between the two perforated plates 5 . One of the perforated plates 5 is connected to the outer side of the longitudinal composite sound-absorbing layer 3 . Several sound-absorbing chambers 4 are divided between two perforated plates 5 by a composite sound-absorbing layer 3 in a transverse direction. Two perforated plates 5 are arranged in parallel, and the composite sound-absorbing layer 3 in a transverse direction is perpendicular to the perforated plates 5 .

The composite sound-absorbing layer 3 is composed of multiple layers of porous sound-absorbing materials with different damping properties to attenuate the sound waves in the sound-absorbing cavity 4 . When the external sound waves vibrate in the sound-absorbing cavity 4 , the sound-wave energy is attenuated and dissipated by the composite sound-absorbing layer 3 .

The perforated plate 5 is composed of several sub-plates 6, and the several sub-plates 6 are in an integrated structure. Several perforations 60 are provided on the sub-board 6 , and the perforations 60 are evenly distributed on the sub-board 6 . The sub-board 6 is arranged on the outer wall and inner wall of the muffler chamber 4, and the perforated structure on the muffler chamber 4 and the sub-board 6 forms a porous muffler mechanism, thereby attenuating sound waves in a higher frequency range through the principle of Helmholtz resonance.

The sub-board 6 is also provided with strip-shaped openings 61 , and the number of the strip-shaped openings 61 can be several. In this embodiment, the number of strip-shaped openings 61 is one. The strip-shaped opening 61 extends N times around the sub-board 6 , where N is greater than 1, so that an elastic region 63 can be formed between adjacent sides of the strip-shaped opening 61 . The strip-shaped opening 61 extends in a zigzag shape or in the shape of a mosquito coil.

The interior of the strip-shaped opening 61 forms a resonance area 62, the exterior of the strip-shaped opening 61 forms a frame area 64, and the area of the strip-shaped opening 61 forms an elastic area 63, and the elastic area 63 is formed by the phase of the strip-shaped opening 61. The area enclosed by adjacent sides. The elastic region 63 acts as an elastic connection, so that the resonance region 62 and the frame region 64 can vibrate freely.

The perforated plate 5 has multi-level topological features, and has different hierarchical topological features at different scales. At the small level, its characteristic is a perforated structure, and at a large level, its topological feature is a resonant structure, so that the perforated plate 5 can simultaneously have the dual noise reduction mechanism of porous noise reduction and local resonance noise reduction, which can better block the noise. Sound waves in different frequency ranges attenuate and block incident sound waves.

For low-frequency sound waves, the low-frequency bandgap characteristics of the structure are formed by the local resonance mechanism of the resonance region 62 and the frame body region 64, so that the incident low-frequency sound waves generate greater energy dissipation when passing through the structure. The upper and lower boundaries of the low-frequency band gap formed by the sub-board 6 correspond to the local resonance frequency of the resonance region 62 and the local resonance frequency of the frame region 64 respectively. Its bandgap frequency can be calculated by establishing an equivalent dynamic model, and adjusted by adjusting the equivalent mass and equivalent stiffness of the structure.

The local resonance sound insulation principle and equivalent dynamic model are as follows:

The work of blocking and dissipating low-frequency sound waves is accomplished through the local resonance structure of the perforated plate 5 . The local resonance structure includes a resonance region 62 , an elastic region 63 and a frame region 64 . Its equivalent kinetic model and calculation model are shown in Fig. 4 below.

When the incident sound wave acts on the surface of the perforated plate 5 , both the resonance region 62 and the frame region 64 will have a local resonance phenomenon in the out-of-plane direction. Its eigenfrequencies are:

Wherein, ω ^s ₀ and ω ^f ₀ represent the eigenfrequencies of the two resonance modes of the local resonance unit respectively, and k _e represents the out-of-plane stiffness of the elastic region 63 . m _e and M represent the equivalent masses of the resonance region 62 and the frame region 64 respectively. Through the frequency domain transformation, the relationship between the equivalent stiffness and equivalent mass of the structure and the frequency of the external input sound wave can be expressed as:

It can be seen that when the sound wave frequency ω is close to the structural natural frequency ω ₀ , its equivalent mass M _eff tends to be infinitely large, while the equivalent stiffness K _eff tends to be infinitely small, thus hindering the transmission of sound waves.

Through the above relationship, the structural parameters can be adjusted according to the sound wave characteristics that need to be blocked, and the noise reduction performance of the acoustic barrier with the set parameters can also be calculated.

For sound waves with higher frequencies, the porous sound-absorbing mechanism formed by the cooperation of the perforations 60 and the sound-absorbing chamber 4 is used to block and dissipate them. At the same time, the composite sound-absorbing layer 3 installed inside the sound-absorbing chamber 4 is used to dissipate the sound wave energy twice.

The series of detailed descriptions listed above are only specific descriptions for feasible implementations of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent implementation or implementation that does not depart from the technical spirit of the present invention All changes should be included within the protection scope of the present invention.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. An acoustic barrier for an anechoic chamber, characterized in that it comprises a mechanical load-bearing structure, an acoustic wedge assembly positioned at the inside of the mechanical load-bearing structure, a longitudinal composite sound-absorbing layer positioned at the outside of the mechanical load-bearing structure, two perforated plates, several A horizontal composite sound-absorbing layer connected between two perforated panels; the two perforated panels are divided into several sound-absorbing cavities by a horizontal composite sound-absorbing layer, and one of the perforated panels is connected to a longitudinal composite sound-absorbing layer; The perforated plate is composed of several sub-plates, the sub-plate is provided with several perforations, and the sub-plate is also provided with a strip-shaped opening, and the strip-shaped opening extends N weeks around the sub-plate, and the inside of the strip-shaped opening is A resonance area is formed, a frame area is formed outside the strip-shaped opening, and an elastic area is formed in the area of the strip-shaped opening. 2 . The acoustic barrier of the anechoic room according to claim 1 , wherein the N is greater than 1. 3 . 3. The acoustic barrier of the anechoic chamber according to claim 2, characterized in that, the elastic region is a region surrounded by adjacent sides of the strip-shaped opening. 4 . The acoustic barrier of the anechoic room according to claim 3 , wherein the strip-shaped openings extend in a reverse shape or in a mosquito-repellent coil shape. 5 . 5. The acoustic barrier of the anechoic chamber according to claim 1, wherein the sub-boards are arranged on the outer wall and the inner wall of the anechoic chamber. 6. The acoustic barrier of the anechoic room according to claim 1, characterized in that several sub-boards are integrated. 7. The acoustic barrier of the anechoic chamber according to claim 6, characterized in that the perforations are uniformly distributed on the sub-plates. 8. The acoustic barrier of the anechoic room according to claim 1, wherein the composite sound-absorbing layer is composed of multiple layers of porous sound-absorbing materials with different damping properties. 9. The acoustic barrier of an anechoic chamber according to claim 1, wherein the mechanical bearing structure is an installation base. 10. The acoustic barrier of the anechoic chamber according to claim 1, wherein the acoustic wedge assembly is a metal plate sandwich wedge structure and a concrete wedge structure.

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