CN208126867U - A kind of honeycomb interlayer sound absorption structure of built-in microperforated panel - Google Patents

Abstract

The utility model discloses a honeycomb sandwich sound-absorbing structure with a built-in micro-perforated plate. The honeycomb sandwich structure is composed of a honeycomb core, an upper panel, a lower panel and an internal micro-perforated plate. The honeycomb core is hollow cylindrical, and the honeycomb An internal micro-perforated plate is set in the core, and the upper panel and the lower panel are respectively arranged on the top and bottom of the honeycomb core. The air cavity formed by the internal micro-perforated plate and the upper panel forms a double Helmholtz resonance cavity, and The air cavity formed by the lower panel forms a resonant cavity together to form a structure with double sound-absorbing performance. The honeycomb cores with internal micro-perforated plates are arranged in groups of six and in groups as a period, and are located in the same group. The six double Helmholtz resonant cavities in the honeycomb core are of different sizes, forming a gradient cavity to form a quadratic residue diffuser. The double sound-absorbing effect of the honeycomb interlayer of the utility model greatly improves the sound-absorbing capacity, and can widen the sound-absorbing frequency band at low frequencies, enhances the overall sound-absorbing performance of the structure, is light in weight, and is light in design.

Description

A honeycomb sandwich sound-absorbing structure with built-in micro-perforated panels

technical field

The utility model relates to a honeycomb sandwich structure, in particular to a honeycomb sandwich sound-absorbing structure in which a micro-perforated plate is added in a honeycomb cavity and a micro-perforated plate is built in.

Background technique

Because the noise in the aircraft cabin has a certain impact on people's physical and mental health and flight experience, the noise control in the aircraft cabin has gradually gained people's attention, so it is necessary to absorb the noise to the greatest extent. Since the aircraft is very sensitive to weight, the design principle is to consume sound energy without increasing the weight, and the honeycomb structure is widely used in aircraft because of its light weight and high specific strength and stiffness. On this basis, if the honeycomb The sandwich structure is designed and installed in the inner wall of the aircraft cabin, which can not only meet the strength requirements, but also absorb noise. The honeycomb core of the honeycomb sandwich structure often adopts hexagonal, rectangular and other structures. The utility model takes the circular honeycomb sandwich structure as the research object, and adds sound damping in the honeycomb core structure in order to further widen the sound absorption frequency band of the honeycomb structure and improve Medium and low frequency sound absorption performance, optimize the environment in the aircraft cabin.

Utility model content

The purpose of this utility model is to provide a honeycomb sandwich sound-absorbing structure with a built-in micro-perforated plate. Taking the circular honeycomb sandwich structure as the research object, by adding sound damping in the honeycomb core structure, in order to further widen the sound-absorbing frequency band of the honeycomb structure, Improve the low-frequency sound absorption effect.

In order to achieve the above object, the utility model is achieved through the following technical solutions:

A honeycomb sandwich sound-absorbing structure with a built-in micro-perforated plate, characterized in that it is composed of a honeycomb core, an upper panel, a lower panel and an internal micro-perforated plate, the honeycomb core is a hollow cylinder, and the cavity of the honeycomb core An internal micro-perforated plate is set, the upper panel and the lower panel are respectively arranged on the top and bottom of the honeycomb core, the air cavity formed by the internal micro-perforated plate and the upper panel forms a double Helmholtz resonance cavity, and the internal The air cavity formed by the micro-perforated plate and the lower panel forms a resonant cavity, and the double Helmholtz resonant cavity and the resonant cavity together form a structure with double sound absorption performance. The honeycomb core with the internal micro-perforated plate has six The six double Helmholtz resonant cavities in the same group of honeycomb cores are arranged in a group and arranged in sequence with a group as a period, and the sizes of the six double Helmholtz resonant cavities are different, forming a gradient cavity to form a quadratic residue diffuser.

Further, the honeycomb cores are closely arranged in a tangential manner.

Further, the upper panel is a micro-perforated structure.

Further, the size ratios of the six double Helmholtz resonators in the same group of honeycomb cores are 2:8:4:2:4:1 in sequence.

Further, the connections between the upper and lower panels and the honeycomb core, between the internal micro-perforated plate and the honeycomb core, and between each honeycomb core are glued connections.

Further, each part of the honeycomb sandwich sound-absorbing structure is made of aluminum alloy.

The utility model is a circular honeycomb sandwich structure. Based on the principle of the Helmholtz resonant cavity, the sound absorption coefficient of the overall structure can be increased by micro-perforating the plate, but the sound absorption frequency band is narrow in the middle and low frequencies, so the frequency band needs to be widened, and the sound absorption coefficient is low. By changing the internal honeycomb structure, the frequency band can be widened and the maximum sound absorption coefficient can be increased. The utility model takes this as a starting point. By setting a micro-perforated plate inside the honeycomb core, on the one hand, the upper micro-perforated plate and the cavity below it can The unequal height sub-back air cavity is formed to form a quadratic residue diffuser, so as to provide additional low-frequency sound absorption effect and widen the sound absorption frequency band. On the other hand, the sound waves pass through the internal micro-perforated plate and form a resonance cavity with the air cavity under the internal perforated plate to consume energy and improve the sound absorption coefficient. This structure only needs to add micro-perforated plates inside the honeycomb core, and the operation is relatively convenient.

The structure of the utility model is relatively simple. On the basis of the original honeycomb sandwich structure, adding some internal micro-perforated plates can improve its sound absorption peak value to a certain extent, and effectively widen the sound absorption frequency band.

Description of drawings

Fig. 1 is a structural schematic diagram of a honeycomb sandwich sound-absorbing structure with a built-in micro-perforated plate of the present invention;

Fig. 2 is a schematic diagram of the arrangement of micro-perforated plates in a group of inner cores;

Fig. 3 is a comparison diagram of the sound absorption coefficient before and after setting the internal micro-perforated plate in the corresponding embodiment 1;

Fig. 4 is a comparison diagram of the sound absorption coefficient before and after setting the internal micro-perforated plate in corresponding embodiment 2;

In the figure: 1. Upper micro-perforated plate, 2. Internal micro-perforated plate, 3. Honeycomb core, 4. Lower panel.

Detailed ways

Now in conjunction with accompanying drawing and embodiment the utility model is described further:

Example 1

In Fig. 1, a honeycomb sandwich sound-absorbing structure with built-in micro-perforated panels, its structure includes an upper micro-perforated panel 1 (its micro-perforations are not shown in the figure), an inner micro-perforated panel 2, a circular honeycomb core 3 and a lower panel 4. The honeycomb cores 3 with internal micro-perforated plates 2 are arranged in groups of six, and then six honeycomb cores 3 with internal micro-perforated plates 2 are arranged in a cycle. Considering the weight and operation reasons, it can be After one row is vacant (as shown in the second row without internal micro-perforated plate 2 in Figure 1), go to the third row and perform the same arrangement as the first row.

The materials of each part of the honeycomb structure are aluminum alloy materials, and each aluminum alloy material is glued and connected. The circular honeycomb core 3 has a height of 60 mm, a diameter of 15 mm, and a wall thickness of 0.5 mm. The upper and lower panels 1 and 4 have a thickness of 0.5 mm. The micro-perforated aperture of the upper micro-perforated panel 1 is 0.5 mm, and the perforation area ratio is 4%. The inner micro-perforated panel 2 has a diameter of 14mm and a thickness of 0.5mm. The perforation is the same as that of the upper micro-perforated panel 1. Each circular honeycomb core 3 is closely connected in a tangential form to form the entire honeycomb core. A set of micro-perforated panels is set. After 2, air cavities of 15, 60, 30, 15, 30, and 7.5 mm are formed on the inner micro-perforated panel 2, as shown in Figure 2, the upper micro-perforated panel 1 and the air cavity formed below it form a secondary remainder diffuser , to broaden the sound absorption frequency band, the inner micro-perforated panel 2 and the air cavity below it form a Helmholtz resonance cavity to increase the sound absorption performance. Through the COMSOL software, the structural model is established in the pressure acoustics module, and the acoustic boundary condition is set as the background pressure field. By integrating the reflected sound energy and the incident sound energy of the incident surface, the sound absorption coefficient can be obtained by substituting it into the formula. The simulation results are shown in Figure 3 As shown in , compared with no built-in micro-perforated plate, the peak value of the sound absorption coefficient is increased by nearly 0.3-0.4, and the sound-absorbing frequency band can increase at least 1 bandwidth under the OCT measurement method.

Example 2

Refer to Figure 1 for the composition of the honeycomb structure. The materials of each part are aluminum alloy materials, and each aluminum alloy material is glued and connected. The circular honeycomb core 3 has a height of 60 mm, a diameter of 15 mm, and a wall thickness of 0.5 mm. The upper and lower panels 1 and 4 have a thickness of 0.5 mm. The micro-perforated aperture of the upper micro-perforated panel 1 is 0.5 mm, and the perforation area ratio is 4%. The diameter of the internal micro-perforated plate 2 is 14mm, the thickness is 0.5mm, the perforation diameter is 0.2mm, and the perforation area ratio is 2%. After the micro-perforated plate, air cavities of 15, 60, 30, 15, 30, and 7.5 mm are formed on the top of the internal micro-perforated plate 2, and air cavities are also formed below it, and the periodic arrangement and sound absorption principle are the same as in Example 1 . Modeling by COMSOL software, the process is similar to that in Example 1. The results are shown in Figure 4. Compared with the built-in micro-perforated plate, the peak value of the sound absorption coefficient is increased by 0.4-0.5, and the sound absorption frequency band can be increased by at least 1.5 bandwidths under the OCT measurement method, and the sound absorption coefficient is significantly improved. Compared with the overall sound absorption effect of the structure of Example 1, it can be used as a preference.

In addition, the selection of structural materials, the perforation diameter and thickness of the upper micro-perforated panel 1, the height of the honeycomb core 3, and the perforation of the internal micro-perforated plate 2 can all be selected according to the actual situation, and the position of the internal micro-perforated plate 2 can also be varied.

The above is only a specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto, and any transformation or replacement that is not thought of through creative labor should be covered within the protection scope of the present utility model .

Claims (6)

1. A honeycomb sandwich sound-absorbing structure with a built-in micro-perforated plate, characterized in that it is composed of a honeycomb core, an upper panel, a lower panel and an internal micro-perforated plate, the honeycomb core is a hollow cylinder, and the hollow of the honeycomb core An internal micro-perforated plate is set in the cavity, and the upper panel and the lower panel are respectively arranged on the top and bottom of the honeycomb core. The air cavity formed by the internal micro-perforated plate and the upper panel forms a double Helmholtz resonance cavity. The air cavity formed by the internal micro-perforated plate and the lower panel forms a resonant cavity, and the double Helmholtz resonant cavity and the resonant cavity together form a structure with double sound absorption performance. The honeycomb core with the internal micro-perforated plate and Six are a group and are arranged sequentially with a group as a period. The six double Helmholtz resonant cavities in the same group of honeycomb cores have different sizes, forming a gradient cavity to form a quadratic residue diffuser. 2. The honeycomb sandwich sound-absorbing structure with built-in micro-perforated panels according to claim 1, wherein the honeycomb cores are closely arranged in a tangential manner. 3. A honeycomb sandwich sound-absorbing structure with built-in micro-perforated panels according to claim 1, characterized in that the upper panel is a micro-perforated structure. 4. The honeycomb sandwich sound-absorbing structure of a kind of built-in micro-perforated plate according to claim 1, is characterized in that, the size ratio of six double Helmholtz resonators in the same group of honeycomb cores is successively 2:8: 4:2:4:1. 5. A honeycomb sandwich sound-absorbing structure with a built-in micro-perforated plate according to claim 1, characterized in that, between the upper and lower panels and the honeycomb core, between the internal micro-perforated plate and the honeycomb core, and between each The honeycomb cores are glued together. 6. A honeycomb sandwich sound-absorbing structure with built-in micro-perforated plates according to claim 1, characterized in that the materials of each part of the honeycomb sandwich sound-absorbing structure are aluminum alloy materials.