Sound absorption body for sound absorption frequency band light modulation

Abstract

The sound absorption body is characterized in that the sound absorption body comprises a light source, a flexible cover plate and at least one sound absorption body back cavity, a channel connected with the outside of the sound absorption body back cavity is formed in the sound absorption body back cavity, the flexible cover plate can cover the opening area of the channel, the flexible cover plate comprises a CNT-Nafion / PE double-layer driver, and the CNT-Nafion / PE double-layer driver is connected with the light source. The light of the light source can drive the CNT-Nafion / PE double-layer driver to deform and enable the channel to be opened or partially opened. According to the invention, the light-actuated CNT-Nafion / PE double-layer driver is used as a flexible panel, the light-actuated CNT-Nafion / PE double-layer driver can cover the opening area of the surface of the channel in a non-illumination state, the driver is deformed after illumination, and the opening of the channel is exposed, so that the sound absorption frequency band of the back cavity of the sound absorber can be adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of low-frequency sound absorption, and more particularly to a sound absorber with light modulation of sound absorption frequency band. Background Art

[0002] The development of industrialization has created more and more low-frequency noise problems, such as traffic noise generated by cars, trains, airplanes, etc.; industrial noise generated by mechanical equipment, production processes and transportation activities in factories and other industrial facilities; and construction noise generated by excavation, piling, concrete pouring and other operations during construction. Research on noise control and treatment runs through the entire industrial development. Traditional sound-absorbing materials based on porous materials and fiber materials have a good absorption effect on high-frequency noise. However, due to the long wavelength of low-frequency sound waves, the structure of traditional sound-absorbing materials is not sufficient to effectively interact with these sound waves, so it is difficult to effectively absorb them. In recent years, the development of acoustic metamaterials has injected new vitality into the absorption of low-frequency noise and provided new ideas for the design of sub-wavelength sound-absorbing structures.

[0003] In addition, the passive sound-absorbing structures currently designed for low-frequency noise can achieve good sound absorption effects within the operating frequency range, but due to the limitations of materials, structures and space, they can usually only work within a narrow frequency range. Although the sound absorption bandwidth of the sound absorber can be expanded by connecting multiple structural parameters in parallel, this will lead to a decrease in the sound absorption coefficient of the sound absorber, and these sound absorbers have complex internal structures. Once their structures are determined, their acoustic properties will not change. With the development of smart materials, the introduction of flexible smart materials into sound-absorbing structures has become a rapidly developing research direction in recent years. At present, electroactive polymers such as piezoelectric polymer PVDF, electroactive polymer DE, and magnetorheological elastomers have been applied to the research of modulatable sound-absorbing structures.

[0004] Carbon nanotube-Nafion / polyethylene composites (CNT-Nafion / PE) are flexible smart materials and a typical multi-stimulus source driver. Currently, there is still no research on light-modulated sound absorption. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to provide a sound absorbing body with light modulation in the sound absorbing frequency band.

[0006] The present invention solves the above-mentioned technical problems through the following technical means: an acoustic absorber with light modulation in a sound absorption frequency band, characterized in that it includes a light source, a flexible cover plate, and at least one acoustic absorber back cavity, wherein a channel connected to the outside of the acoustic absorber back cavity is opened on the acoustic absorber back cavity, and the flexible cover plate can cover the opening area of ​​the channel, and the flexible cover plate includes a CNT-Nafion / PE double-layer driver, wherein the CNT-Nafion layer and the PE layer are respectively located on the side away from and toward the acoustic absorber back cavity, and the light from the light source can drive the CNT-Nafion / PE double-layer driver to deform and cause the channel to open or partially open.

[0007] By using the light-activated CNT-Nafion / PE double-layer driver as a flexible panel, it will cover the opening area on the surface of the channel in the absence of light. When exposed to light, the driver will deform and the opening of the channel will be exposed, thereby adjusting the sound absorption frequency band of the back cavity of the sound absorber.

[0008] As a preferred technical solution, the light from the light source is unevenly arranged and can drive the CNT-Nafion / PE double-layer actuator to produce different deformations.

[0009] By setting uneven lighting, the surface deformation pace of each CNT-Nafion / PE double-layer driver is not uniform, which can make the flexible cover plate produce complex surface deformation, further increasing the sound absorption frequency range; when the sound wave is incident on the gap and channel between the channel and the flexible panel, the sound absorber will resonate. At this time, the gas molecules driven by the sound wave will move rapidly in the narrow space. At this time, the air molecules will produce a thermoviscous effect with the channel, which will convert the mechanical energy in the sound wave into heat energy, thereby absorbing the sound wave energy.

[0010] As a preferred technical solution, it also includes a box body, the inner cavity of the box body forms a sound absorber back cavity, the box body has a channel at one end facing the light source, and the flexible cover is fixedly connected to the end of the box body facing the light source and is located outside the channel.

[0011] As a preferred technical solution, the box body includes a sound absorber panel and a sound absorber shell, and the sound absorber panel and the sound absorber shell are fixedly enclosed to form a sound absorber back cavity.

[0012] As a preferred technical solution, the flexible cover is arranged outside the back cavity of the sound absorber and is bonded and fixed to the back cavity of the sound absorber. The flexible cover includes a fixed end and a free end, and the free end can be bent along the long side or short side of the flexible cover.

[0013] The flexible cover plate can produce resonance under the action of sound waves, so that the energy of the sound waves is transferred to the flexible cover plate and finally converted into heat energy, so that the flexible cover plate produces additional sound absorption effect.

[0014] As a preferred technical solution, one long side of the flexible cover plate forms the fixed end, and the other long side forms the free end, and the free end can be bent relative to the fixed end.

[0015] When light shines on the surface of the flexible cover, the bending deformation of the flexible cover changes the acoustic characteristics of the sound absorber, causing the sound absorption band of the sound absorber to move toward high frequency. At the same time, during the entire frequency modulation process, the sound absorber has a sound absorption coefficient of more than 0.9, and in some states the sound absorption coefficient can reach 1, achieving perfect sound absorption.

[0016] As a preferred technical solution, the middle part of the end of the flexible cover plate forms the fixed end, and the two long sides form free ends, and both can be bent relative to the fixed end.

[0017] Setting the opening mode of the flexible cover to open on both sides can better cover the micro-slits on the sound absorber panel, so that the sound absorber in the initial state can work in a lower frequency band.

[0018] As a preferred technical solution, the channel includes a plurality of evenly distributed micro-slits, and the flexible cover plate is arranged corresponding to the micro-slits.

[0019] By evenly arranging micro gaps, the utilization of sound pressure can effectively enhance the thermal viscosity dissipation at the micro gaps, which plays an important role in improving the sound absorption effect of the sound-absorbing structure.

[0020] As a preferred technical solution, the back cavity of the sound absorber is provided with flexible cover plates which are arranged in parallel and spaced apart. After the flexible cover plates are introduced, their blocking effect on sound waves will cause the natural frequency of the sound absorber to change. At the same time, before entering the interior of the sound absorber, the sound waves will first pass through the gap between the flexible cover plate and the sound absorber panel. The thermal viscosity effect here will bring additional sound absorption effect to the sound absorber. The photo-actuated characteristics of the flexible panel are combined with the sound absorption characteristics of the micro-slit structure, and the frequency band of the sound absorption is changed by causing complex deformation when it is illuminated to meet different low-frequency sound absorption requirements.

[0021] As a preferred technical solution, it also includes a controller, which is electrically or communicatively connected to the light source and can adjust the light intensity of the light source.

[0022] As a preferred technical solution, the sound-absorbing back cavities are provided with multiple ones, and the multiple sound-absorbing back cavities are fixedly connected in sequence. Through the arrangement of multiple sound-absorbing back cavities, they can be freely arranged or arranged in a row in the space to perform sound absorption treatment on the environment, which can effectively increase the sound absorption bandwidth.

[0023] As a preferred technical solution, sound absorbers with different modulation ranges can be produced by changing the width of the micro-slits on the sound absorbing panel.

[0024] As a preferred technical solution, the box body is made of metal or non-metallic material, the metal material includes aluminum plate, galvanized plate or stainless steel plate, and the non-metallic material includes plastic plate or gypsum board. By setting the box body material to metal material, its own sound insulation performance is better, not only can it meet the requirements of low-frequency sound absorption, but its weighted sound insulation is generally not less than 30dB, which can meet the conventional sound insulation and noise reduction requirements, and can meet the comprehensive noise reduction requirements of sound absorption and sound insulation.

[0025] The beneficial effects of the present invention are:

[0026] (1) In the present invention, a light-activated CNT-Nafion / PE double-layer driver is used as a flexible panel, which covers the opening area on the surface of the channel in the absence of light. When exposed to light, the driver is deformed and the opening of the channel is exposed, thereby adjusting the sound absorption band of the back cavity of the sound absorber. The sound absorber exerts a modulation effect under the stimulation of a light source such as sunlight or an artificial light source. When light is irradiated onto the surface of the flexible cover plate, the bending deformation of the flexible cover plate changes the acoustic characteristics of the sound absorber, thereby shifting the sound absorption band of the sound absorber toward high frequency. By combining a carbon nanotube-Nafion / polyethylene composite material, a light-modulated sound absorber is designed, which realizes non-contact adjustable sound absorption performance over a wide range.

[0027] (2) In the present invention, different light intensities can be applied to multiple flexible cover plates through a controller, so that the deformation pace of each CNT-Nafion / PE flexible cover plate is not uniform, which can cause the flexible cover plate to produce complex curved surface deformation, further increasing the sound absorption frequency range; by adjusting the width of the micro-slit, sound absorbers with different modulation ranges can be obtained, and these sound absorbers can be placed in a space in a progressive combination and arrangement, which can effectively increase the sound absorption bandwidth.

[0028] (3) In the present invention, the gap between the flexible cover plate and the micro-slit plate and the thermal viscous dissipation generated at the micro-slit will directly convert the energy of the sound wave into thermal energy, and finally dissipate it through heat conduction. This double thermal viscous dissipation realizes the absorption of noise energy. In addition, the freely vibrating flexible cover plate can convert the energy of the sound wave into the mechanical energy of the vibration of the flexible cover plate, and finally the mechanical energy will be converted into thermal energy dissipation, thereby achieving a partial sound absorption effect and providing an additional way for the sound absorber to dissipate sound energy.

[0029] (4) In the present invention, by setting the box body material to metal material, the sound insulation performance itself is better, not only can it meet the requirements of low-frequency sound absorption, but its weighted sound insulation is generally not less than 30dB, which can meet the conventional sound insulation and noise reduction requirements, and can meet the comprehensive noise reduction requirements of sound absorption and sound insulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the explosion structure of the sound absorber provided in Example 1 of the present invention;

[0031] Figure 2 A schematic diagram of a light-shielding state of a sound absorber provided in Embodiment 1 of the present invention;

[0032] Figure 3 A schematic diagram of the bending structure of the sound absorber panel provided in Example 1 of the present invention;

[0033] Figure 4 This is a diagram showing the sound absorption performance measurement results of the light modulating sound absorption structure provided in Example 1 of the present invention when no light is applied;

[0034] Figure 5 A diagram showing the results of measuring the sound absorption performance of the light modulated sound absorbing structure provided in Example 1 of the present invention when light is applied;

[0035] Figure 6 A schematic diagram of the explosion structure of the sound absorber provided in Example 2 of the present invention;

[0036] Figure 7 A schematic diagram of the structure of a sound absorber in a light-shielding state provided in Embodiment 2 of the present invention;

[0037] Figure 8 A schematic diagram of the curved structure of the sound absorber panel provided in Example 2 of the present invention;

[0038] Fig. 9 A schematic diagram of the sound absorption performance measurement results of the light modulated sound absorption structure provided in Example 2 of the present invention when no light is applied;

[0039] Fig.10 A diagram showing the results of measuring the sound absorption performance of the light modulated sound absorbing structure provided in Example 2 of the present invention when light is applied;

[0040] Figure Number:

[0041] 11. Flexible cover plate; 111. Fixed end; 112. Free end; 12. Sound absorber panel; 121. Micro gap; 13. Sound absorber back cavity; 14. Sound absorber shell. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] See also Figure 1, a sound absorbing body with light modulation in a sound absorption frequency band, comprising a light source, a flexible cover plate 11, and a back cavity 13 of the sound absorbing body. The back cavity 13 of the sound absorbing body is a closed cavity structure, on which a channel connected to the outside is opened. In this embodiment, the channel can be a micro-slit 121, and of course it can also be a through hole; the flexible cover plate 11 is arranged on the outside of the back cavity 13 of the sound absorbing body. In this embodiment, the flexible cover plate 11 is a CNT-Nafion / PE double-layer driver. The flexible cover plate 11 can completely cover or partially cover the top opening area of ​​the channel under normal conditions. Normal conditions refer to that when avoiding light, the flexible cover plate 11 does not deform or the degree of deformation is negligible; wherein the CNT-Nafion layer is arranged away from the back cavity 13 of the sound absorbing body, and the PE layer is arranged toward the back cavity 13 of the sound absorbing body;

[0045] When exposed to light, CNT's excellent photothermal conversion ability will convert light energy into heat energy, and the overall temperature of the driver will rise. The illumination can be uniform or uneven. Uneven illumination can cause the deformation of each CNT-Nafion / PE double-layer driver to be inconsistent, which can cause the flexible cover 11 to produce complex curved surface deformation, further increasing the sound absorption frequency range; the temperature increase causes the water in the CNT-Nafion layer to evaporate, the volume to decrease, and a pseudo-heat shrinkage phenomenon occurs; the PE layer has a large thermal expansion coefficient, and the temperature increase will cause it to expand due to heat. The stress mismatch between the two layers of material will cause the double-layer driver to bend toward the CNT-Nafion layer; by applying light of different intensities to the driver to control the deformation of the CNT-Nafin / PE driver, the structure of the sound absorber can be changed, thereby changing the sound absorption frequency band of the overall structure;

[0046] The illumination comes from a light source, which may be a natural light source such as sunlight, or an artificial light source such as a torch, an oil lamp, a candle, an electric lamp, etc. The electric lamp may be an incandescent lamp, a fluorescent lamp, a high-pressure xenon lamp, etc. In this embodiment, the light source is a xenon lamp light source as an example, but is not limited thereto. It may also be replaced with other light sources mentioned above according to actual application scenarios. A controller may also be provided, and the controller is electrically or communicatively connected to the xenon lamp to adjust the illumination intensity of the light source. In this embodiment, the illumination intensity applied by the light source is 20-260 mW / cm 2 .

[0047] See also Figure 1The sound-absorbing body back cavity 13 is formed in a closed box body, which includes a sound-absorbing body panel 12 and a sound-absorbing body shell 14. The sound-absorbing body shell 14 is an open shell structure that is circumferentially closed, opened at one end toward the light source, and closed at one end away from the light source. The sound-absorbing body panel 12 is fixedly connected to the open area of ​​the sound-absorbing body shell 14. The sound-absorbing body panel 12 is fastened to the sound-absorbing body shell 14 by bolts to form the above-mentioned sound-absorbing body back cavity 13; in this embodiment, the box body formed by the sound-absorbing body panel 12 and the sound-absorbing body shell 14 is in the shape of a rectangular parallelepiped, and of course, it can also be set in the shape of a cube, a cylinder, a cone, or other special shapes, and the sound-absorbing body panel 12 and the sound-absorbing body shell 14 are formed with bolt holes adapted to the bolts at the four corners;

[0048] It should be noted that the sound absorber panel 12 and the sound absorber shell 14 are made of metal or non-metal materials, wherein the metal materials include but are not limited to aluminum plates, galvanized plates or stainless steel plates; the above metal materials have excellent sound insulation performance, which can not only meet the requirements of low-frequency sound absorption, but also the weighted sound insulation value is generally not less than 30dB, which can meet the conventional sound insulation and noise reduction requirements, that is, the comprehensive noise reduction requirements of sound absorption and sound insulation; non-metal materials include plastic boards or gypsum boards.

[0049] In the initial light-shielding state, the flexible cover 11 will be attached to the sound absorber panel 12. At this time, the sound absorber is similar to a membrane sound absorber. By increasing the thickness of the flexible cover 11, the resonance frequency of the sound absorber will be reduced, which will cause the sound absorption frequency band of the sound absorber to move to low frequency, thereby enhancing its low-frequency sound absorption effect. Of course, the increase in the thickness of the flexible cover 11 will reduce the light-driven performance of the material, and a greater light intensity is required for its bending at a certain angle. In this embodiment, the thickness of the flexible cover 11 is 50 microns-200 microns; the increase in the length and width of the flexible cover 11 will cause the depth of the slit between the flexible cover 11 and the sound absorber panel 12 to increase. The slit refers to the gap between the flexible cover 11 and the sound absorber panel 12 after bending. A deeper slit usually reduces the resonance frequency, causing the sound absorption frequency band to move to low frequency. At the same time, the area where the sound wave energy undergoes thermal viscous dissipation will increase. Appropriate adjustment of the depth of the slit can bring a larger sound absorption bandwidth to the sound absorber.

[0050] See also Figure 1 , Figure 2, a plurality of micro-slits 121 are evenly provided on the sound-absorbing panel 12, and the micro-slits 121 are generally rectangular, and can also be circular, waist-shaped, etc., and the uniform distribution can be linear, circumferential, array, etc. In this embodiment, the length of the flexible cover plate 11 is 30mm-50mm, preferably 40mm, the width of the flexible cover plate 11 is 3mm-10mm, and the width of the micro-slits 121 is 0.5-4mm. By changing the width of the micro-slits 121, sound absorbers with different modulation ranges can be produced; In this embodiment, the micro-slits 121 are rectangular, and five are provided, which are linearly parallel and spaced apart; the utilization of the uniform structure with the sound pressure can effectively enhance the thermal viscosity dissipation at the micro-slits 121, which plays an important role in improving the sound absorption effect of the sound-absorbing structure;

[0051] When sound waves are incident on the micro-slit sound absorber composed of the micro-slit 121 and the sound absorber back cavity 13, the micro-slit sound absorber will resonate. At this time, the gas molecules driven by the sound waves will move rapidly in the narrow place. At this time, the air molecules will produce a thermal viscosity effect with the micro-slit 121, which will convert the mechanical energy in the sound wave into heat energy, thereby absorbing the sound wave energy; after the flexible cover plate 11 is deformed, its blocking effect on the sound wave will cause the natural frequency of the sound absorber to change;

[0052] Before entering the sound absorber, the sound wave will first pass through the gap between the flexible cover 11 and the sound absorber panel 12. The thermal viscosity effect here will bring additional sound absorption effect to the sound absorber. The photo-actuated characteristics of the flexible cover 11 are combined with the sound absorption characteristics of the micro-slit 121 structure, and the frequency band of the sound absorption is changed by generating complex deformations when illuminated to meet different low-frequency sound absorption requirements.

[0053] See also Figure 2 , Figure 3 The flexible cover plate 11 includes a fixed end 111 and a free end 112. The fixed end 111 and the free end 112 are an integral structure, and of course they can also be fixedly connected. The fixed end 111 is fixedly connected to the outside of the sound absorbing panel 12. In this embodiment, the fixed end 111 is bonded to the top of the sound absorbing panel 12 by an elastic tape. The free end 112 can completely or partially cover the top opening area of ​​the micro-slit 121 under normal conditions. The flexible cover plates 11 are correspondingly provided with five, and are arranged on the outside of the top opening area of ​​the micro-slit 121, and are sequentially provided corresponding to each flexible cover plate 11;

[0054] In this embodiment, taking the case where one long side of the fixed end 111 is bonded to the sound absorber panel 12 as an example, the flexible cover plate 11 will bend along the short side when exposed to light; of course, both long sides may be bonded to the sound absorber panel 12 .

[0055] Working principle: When the sound wave propagates to the board surface 12 of the sound absorbing body of the sound absorbing structure and passes through the gap between the flexible cover plate 11 and the sound absorbing body panel 12, the sound wave will be attenuated for the first time due to the thermal viscosity effect between the sound wave and the gap between the flexible cover plate 11 and the sound absorbing body panel 12. When the sound wave is transmitted to the micro-slit 121 on the sound absorbing body panel 12, the thermal viscosity effect between the sound wave and the side wall of the micro-slit 121 will attenuate the sound wave again. The heat energy generated by the thermal viscosity effect will be dissipated through heat conduction. By controlling the intensity of light, the bending angle of the flexible cover plate 11 can be accurately controlled. When the state of the flexible cover plate 11 is different, the acoustic impedance of the sound absorber will change, so that the sound absorption frequency band of the sound absorber will move, achieving the effect of light modulation sound absorption.

[0056] Its advantage lies in that the dual thermal viscous dissipation effect of the gap between the flexible cover plate 11 and the sound absorber panel 12 and the micro-slit 121 on the sound absorber panel enhances the dissipation of sound wave energy by the sound absorber; the vibration of the flexible cover plate 11 under the action of sound waves conforms to the law of energy conversion to convert sound energy into mechanical energy attached to the flexible cover plate 11, and finally into heat energy, providing an additional way for the sound absorber to dissipate sound energy; by utilizing the light-driven characteristics of the CNT-Nafion / PE double-layer driver combined with the low-frequency absorption characteristics of the sound absorbing structure, the sound absorption frequency band can be changed by applying light to it to produce complex deformation, thereby meeting the sound absorption requirements of different frequency bands.

[0057] Proof of sound absorption performance:

[0058] The sound absorption performance of the light modulated micro-slit sound absorber in this embodiment is measured, and the measurement method is as follows:

[0059] The sound absorption coefficient and acoustic impedance of the light modulated micro-slit sound absorber are measured by an impedance tube. After a series of adjustments to the relevant equipment, a set of data is finally measured and then plotted into a data graph. The specific test method can refer to the national standard "GBT 18696.2-2002 Measurement of sound absorption coefficient and acoustic impedance in acoustic impedance tubes Part 2 Transfer function method".

[0060] See also Figure 4 , Figure 5 It can be seen that the light-modulated micro-slit sound-absorbing structure has excellent sound absorption performance. Applying different light intensities to the sound absorber can deform the flexible cover 11 and change its acoustic characteristics. The sound absorber can play a modulation effect under the stimulation of the light source. When light is irradiated to the surface of the flexible cover 11, the bending deformation of the flexible cover 11 changes the acoustic characteristics of the sound absorber, so that the sound absorption frequency band of the sound absorber moves to the high frequency. At the same time, during the frequency modulation process, the sound absorber has a sound absorption coefficient of more than 0.9. In some states, the sound absorption coefficient can reach 1 to achieve perfect sound absorption. It should be noted that applying different light intensities to the light-modulated micro-slit sound-absorbing structure is a preferred solution.

[0061] Example 2

[0062] See also Figure 6 , Figure 7 , Figure 8 The difference between this embodiment and Embodiment 1 is that the flexible cover plate 11 is bonded and fixed to the sound absorber panel 12 through its short sides. Specifically, the middle part of the flexible cover plate 11 is fixedly connected to the sound absorber panel 12.

[0063] There are three ways to fix the short side to the sound absorber panel 12. The first is to fix the short side to the sound absorber panel 12 by bonding, the second is to fix the short side to the sound absorber panel 12 by bonding, and the third is to fix the middle of the short side to the sound absorber panel 12. In this embodiment, the design principle is introduced in the third way, and the middle of the short side is fixedly connected to the sound absorber panel 12. This way allows the sound absorber to better cover the micro-slits 121 on the sound absorber panel 12 in the absence of light, so that the sound absorber in the initial state can work in a lower frequency band. At the same time, the opening method of the flexible cover 11 is changed from the previous single-sided opening to the double-sided opening along the central axis in the length direction.

[0064] It should be noted that in this embodiment, the width of the micro-slits 121 on the sound absorber panel 12 is increased, so that the sound absorber has a larger perforation rate when the flexible cover 11 is opened, so that its sound absorption frequency can be modulated to a higher frequency, effectively increasing the sound absorption bandwidth. In this embodiment, when the middle part of the fixed end of the flexible cover 11 is fixed to the sound absorber panel 12, the sound absorption coefficient in the dark state is less than 0.9.

[0065] See also Fig. 9 The change in the fixing method of the flexible cover plate 11 makes the sound absorption band of the sound absorber move to a lower level. The fixing method of the flexible cover plate 11 with both sides open effectively increases the thermal viscosity loss between the flexible cover plate 11 and the sound absorber panel 12. Fig.10 The double-sided opening mode of the flexible cover plate 11 increases the modulatable sound absorption frequency band of the sound absorber, and also makes the sound absorption frequency achieve a nearly perfect sound absorption effect.

[0066] Example 3

[0067] The difference between this embodiment and embodiment 1 is that the sound absorber in this embodiment includes a plurality of sound absorbing cavities with different reference frequencies. By combining and arranging the sound absorbing cavities with different reference frequencies, the sound absorption bandwidth can be effectively increased. By changing the width of the micro-slits 121 on the sound absorber panel 12, a sound absorbing structure with different reference frequencies can be produced, which can be placed in cabins such as high-speed trains and airplanes or other application scenarios where sound absorption is required.

[0068] Example 4

[0069] The difference between this embodiment and embodiments 1, 2, and 3 is that in this embodiment, a method for preparing a flexible cover plate 11 is provided, comprising the following steps:

[0070] S1. First, the Nafion solution, organic solvent DMAC and CNT were subjected to magnetic stirring at 300 r / min for 3 h in a mass ratio of 3:1:0.015, and then the sample was ultrasonically treated in an ice water bath using a probe ultrasonic cell crusher to effectively reduce the agglomeration of CNT and promote its further dispersion;

[0071] S2, then placing the CNT-Nafion with uniformly dispersed CNT in a vacuum box, evacuating it, and keeping it in a vacuum state for 15 minutes to remove the dissolved gas in the solution;

[0072] S3. Place a glass slide on a heating platform. The size of the glass slide is 75 mm × 25 mm. Take 1 mL of CNT-Nafion solution and drip it on the glass slide. Set the temperature of the heating platform to 50 ° C to dry the material.

[0073] S4, after the drying is completed and the glass slide is cooled and returned to room temperature, the entire slide is placed in deionized water, and the film is automatically peeled off from the glass slide, and the film is taken out and the surface moisture is absorbed by filter paper to finally obtain a dry CNT-Nafion film;

[0074] S5. Cut the obtained CNT-Nafion film into a suitable size such as 8 mm×40 mm. Since the flexible cover plate 11 needs to be bent along the short axis direction, the width direction of the CNT-Nafion film is pasted along the direction of the maximum thermal expansion coefficient of the PE layer. The PE layer can be a commercially available industrial PE tape.

[0075] The CNT-Nafion / PE double-layer actuator has the advantages of fast response, large deformation and environmental friendliness.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sound absorbing body with light modulation in sound absorption band, characterized in that: The invention comprises a light source, a flexible cover plate, and at least one sound absorber back cavity, wherein the sound absorber back cavity is provided with a channel connected to the outside of the sound absorber back cavity, and the flexible cover plate can cover the opening area of ​​the channel. The flexible cover plate comprises a CNT-Nafion / PE double-layer driver, wherein the CNT-Nafion layer and the PE layer are respectively located on the side away from and toward the sound absorber back cavity, and the light from the light source can drive the CNT-Nafion / PE double-layer driver to deform and cause the channel to open or partially open.

2. The sound absorbing body with light modulation in sound absorption band according to claim 1, characterized in that: The light from the light source is unevenly arranged and can drive the CNT-Nafion / PE double-layer actuator to produce different deformations.

3. The sound absorbing body with light modulation in sound absorption band according to claim 1, characterized in that: It also includes a box body, the inner cavity of the box body forms a sound-absorbing body back cavity, a channel is opened at one end of the box body facing the light source, and the flexible cover is fixedly connected to the end of the box body facing the light source and is located outside the channel.

4. The sound absorbing body with light modulation in sound absorption band according to claim 3, characterized in that: The box body comprises a sound absorbing panel and a sound absorbing shell, and the sound absorbing panel and the sound absorbing shell are fixedly enclosed to form a sound absorbing back cavity.

5. The sound absorbing body with light modulation in sound absorption band according to claim 1, characterized in that: The flexible cover plate is arranged outside the back cavity of the sound absorber and is bonded and fixed to the back cavity of the sound absorber. The flexible cover plate includes a fixed end and a free end. The free end can be bent along the long side or short side of the flexible cover plate.

6. The sound absorbing body with light modulation in sound absorption band according to claim 5, characterized in that: One long side of the flexible cover plate forms the fixed end, and the other long side forms the free end, and the free end can be bent relative to the fixed end.

7. The sound absorbing body with light modulation in sound absorption band according to claim 5, characterized in that: The middle part of the end of the flexible cover plate forms the fixed end, and the two long sides form free ends, and both can be bent relative to the fixed end.

8. The sound absorbing body with light modulation in sound absorption band according to claim 1, characterized in that: The channel includes a plurality of uniformly distributed micro-slits, and the flexible cover plate is arranged corresponding to the micro-slits.

9. The sound absorbing body with light modulation in sound absorption band according to claim 1, characterized in that: The invention also includes a controller which is electrically or communicatively connected to the light source and can adjust the light intensity of the light source.

10. The sound absorbing body with light modulation in sound absorption frequency band according to claim 1, characterized in that: The sound absorbing back cavities are provided in plurality, and the plurality of sound absorbing back cavities are fixedly connected in sequence.

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