Honeycomb plate / spinning composite sound absorption structure and preparation method and application thereof

Abstract

The invention provides a honeycomb plate / spinning composite sound absorption structure and a preparation method and application thereof.The honeycomb plate / spinning composite sound absorption structure comprises a substrate (1), a honeycomb plate (2), a TiO2 nanofiber layer (3) and a perforated plate (4) which are sequentially bonded from bottom to top, the thickness of the perforated plate is 0.5-0.8 mm, the hole diameter of perforated holes in the perforated plate is 0.8-1 mm, the hole pitch of the perforated holes is 2.5-3 mm, and the perforation rate is 8.48-9%; the thickness of the TiO2 nanofiber layer is 0.5 to 1mm, and the density of the TiO2 nanofiber layer is 0.016 to 0.024 g / cm < 3 >. The core function of the perforated plate in the honeycomb plate / spinning composite sound absorption structure is to trigger Helmholtz resonance; the TiO2 nanofiber layer is mainly used for micro energy consumption and porous sound absorption; the core function of the cellular board is to provide a rigid cavity and an additional acoustic effect; due to the existence of the base, the whole structure forms a closed structure, and the effects of light weight and high structural strength are achieved structurally.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sound-absorbing and sound-insulating materials, in particular to a honeycomb panel / spun composite sound-absorbing structure and a preparation method and application thereof. BACKGROUND

[0002] Noise in urban areas and noise generated by construction work. The consequence of this noise is to cause outer hair cell (OHC) damage, so it is urgent to solve the problem by using sound-absorbing and sound-insulating materials to reduce noise. Sound-absorbing materials are effective media for inhibiting the propagation of sound waves, mainly divided into traditional porous materials and resonant materials. Traditional porous sound-absorbing materials are difficult to dissipate low-frequency and medium-frequency sound waves, and resonant materials more effectively convert sound energy into heat energy through internal loss mechanisms to dissipate low-frequency and medium-frequency sound waves. Resonant materials include Helmholtz resonators, micro-perforated panels and acoustic metamaterials. However, most resonant materials only exhibit good absorption in certain frequency bands, making it difficult to meet the actual needs in a wide frequency range.

[0003] Foreign research status:

[0004] ①Structure optimization and application of intelligent algorithms: foreign scholars widely use intelligent algorithms to optimize the acoustic performance of composite structures. For example: 1. By adding sound caps inside the honeycomb structure and adjusting their positions, the sound-insulating and sound-absorbing performance is significantly improved. 2. Using simulated annealing algorithm to optimize multi-layer micro-perforated panel structure, effectively broadening the sound-absorbing bandwidth. 3. Using limited combination micro-perforated structure optimization method, providing a new idea for wideband sound-absorbing design. ②Development of new composite materials: CFRP-honeycomb aluminum sandwich composite structure performs outstandingly in the field of automotive NVH (noise, vibration and harshness), its sound-insulating performance is close to that of aluminum honeycomb structure, but its sound-absorbing performance is better, and it is suitable for engine noise reduction and vehicle body sound insulation. Acoustic metamaterials (such as thin film type and local resonance type) achieve low-frequency and high-efficiency sound absorption through periodic structure design, and have become a research hotspot in recent years. ③Multidisciplinary research: combining material science, acoustic theory and computational simulation technology, the mechanical and acoustic performance of composite structures is optimized.

[0005] Domestic research status:

[0006] ① Theoretical model and algorithm optimization: Based on the micro-perforated panel theory of Ma Dajiu, domestic scholars have derived the acoustic impedance model of multi-aperture honeycomb composite structure, and verified the optimization effect through simulation. Xiong Yi et al. use particle swarm optimization algorithm to optimize the structure parameters (perforation rate, aperture, etc.) of honeycomb-micro-perforated panel, and achieve sound absorption coefficient ≥0.8 in the frequency range of 200-2000Hz. ② New composite structure design: Honeycomb-micro-perforated corrugated structure has both mechanical bearing and low-frequency wide-band noise reduction performance. The low-frequency wide-band sound absorption composite structure (invention patent) realizes more than 75% sound absorption efficiency in the frequency range of 210-600Hz by embedding a curled space metamaterial, and has the advantages of light weight and low cost. ③ Industrialization and market application: The aluminum honeycomb sound absorption panel is driven by the green building material policy, and is expected to have a compound growth rate of 8%-10% by 2025. The application of stone honeycomb composite board in the building field is expanding, and intelligent production lines and environmentally friendly materials have become the focus of upgrading.

[0007] Foreign research focuses on algorithm innovation and metamaterial design, while domestic research has made significant progress in theoretical models and industrialization. In the future, we need to further explore the mechanism of wide-band sound absorption and improve the comprehensive performance and economy of composite structures.

[0008] Currently, the most popular sound absorber on the market is a porous sound absorber made of foam and mineral wool. Porous materials have low sound absorption coefficients for low-frequency sound waves (<250Hz), and increasing thickness or density can improve the sound absorption, but the cost and volume increase significantly. Moreover, the uniformity of material porosity directly affects the stability of sound absorption, and the production process requires high precision. Traditional porous materials need to be optimized and selected according to actual needs (such as choosing hydrophobic rock wool or environmentally friendly polyester fiber), and composite design is used to overcome the limitations of single materials. In low-frequency noise-dominated scenarios, the use of Helmholtz resonators and thin film sound absorption structures can improve low-frequency sound absorption. Another common sound absorber is the Helmholtz resonator, which is a sound absorption device based on resonance principle. It absorbs sound energy of specific frequency through the resonance effect of cavity and neck structure. Although it has significant sound absorption effect in the medium and low frequency range (especially in the low frequency range), the sound absorption frequency band of Helmholtz resonator is relatively narrow, usually only effective for sound waves near the target resonance frequency (±10%~20%), suitable for processing low-frequency noise (such as 100~500Hz), but limited for medium and high frequency sound waves (>1000Hz), and needs to be combined with other wide-band sound absorption materials (such as porous materials) to cover a wider frequency range. Both porous material sound absorbers and Helmholtz sound absorbers cannot achieve wide-band sound absorption. SUMMARY

[0009] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a honeycomb panel / spinning composite sound absorption structure and its preparation method and application, to solve the problem that the existing sound absorption materials only show good absorption in certain frequency bands, and are difficult to meet the actual needs in a wide frequency range.

[0010] To achieve the above object and other related objects, the present application provides a honeycomb plate / spinning composite sound absorption structure, comprising a substrate (1), a honeycomb plate (2), a TiO2 nanofiber layer (3) and a perforated plate (4) which are sequentially bonded from bottom to top, the thickness of the perforated plate is 0.5-0.8mm, the aperture of the perforation in the perforated plate is 0.8-1mm, the hole spacing of the perforation is 2.5-3mm, and the perforation rate is 8.48-9%; the thickness of the TiO2 nanofiber layer is 0.5-1mm, and the density is 0.016-0.024 g / cm 3 .

[0011] The honeycomb plate / spinning composite sound absorption structure of the present application has the effects of low-frequency sound absorption, wide-frequency sound absorption and light weight, etc., and the core role of the perforated plate in the above structure is to trigger "Helmholtz resonance"; the role of the TiO2 nanofiber layer is to serve as the main force of micro energy consumption and "porous sound absorption"; the core role of the honeycomb plate is to provide rigid cavities and additional acoustic effects; the existence of the substrate makes the whole structure form a closed structure.

[0012] Preferably, the substrate is a solid iron plate or a solid plastic plate with a thickness of 0.8-1mm.

[0013] Preferably, the honeycomb plate is an aramid honeycomb plate which is uniformly distributed with a plurality of honeycomb cells, the upper surface and the lower bottom surface of the honeycomb cell are hexagonal in cross section; and the contact surface of the adjacent two honeycomb cells is completely contacted.

[0014] The perforated plate is prepared by using polylactic acid as the raw material and adopting 3D printing process.

[0015] The present application also provides a preparation method of the honeycomb plate / spinning composite sound absorption structure, comprising the following steps: spraying a TiO2 nanofiber layer on the lower surface of the perforated plate, and then sequentially bonding with the honeycomb plate and the substrate to form a closed structure, thereby obtaining the honeycomb plate / spinning composite sound absorption structure.

[0016] Preferably, the TiO2 nanofiber layer is prepared by airflow spinning process of TiO2 nanospinning precursor solution on the lower surface of the perforated plate.

[0017] Preferably, the TiO2 nanospinning precursor solution uses a mixture of ethanol and acetic acid as the solvent, and uses tetrabutyl titanate and polyvinylpyrrolidone as the solute, and is formed after uniform mixing and heat treatment.

[0018] Preferably, the mass ratio of the ethanol and acetic acid is (2-3):1; the molecular weight of the polyvinylpyrrolidone is 1300000; the mass ratio of the tetrabutyl titanate and polyvinylpyrrolidone is (3-4):1, the heat treatment temperature is 500-600℃, and the heating rate is controlled at 1-2℃ / min.

[0019] Preferably, the mass percentage of polyvinylpyrrolidone in the TiO2 nanospinning precursor solution is 4-9%.

[0020] Preferably, the parameters of the air flow spinning process are as follows: the injection rate of the injection pump is 1.0-5.0 mL / h, the air flow velocity at the outlet of the outer shaft is 20-25 m / s, and the relative humidity in the room is controlled at 30-50%.

[0021] The application also provides a use of the honeycomb panel / spinning composite sound absorption structure in the preparation of a low-frequency broadband sound absorption material.

[0022] As described above, the application has the following beneficial effects:

[0023] (1) The core role of the perforated plate in the honeycomb panel / spinning composite sound absorption structure is to induce "Helmholtz resonance"; the role of the TiO2 nanofiber layer is to serve as a micro energy consumption and "porous sound absorption" main force; the core role of the honeycomb plate is to provide a rigid cavity and additional acoustic effect; the presence of the base makes the entire structure form a closed structure, which has the effects of lightweight and high structural strength in structure;

[0024] (2) The TiO2 nanofiber layer is prepared by air flow spinning, and by adjusting the air flow velocity, temperature, solution flow rate and receiving distance, the fiber diameter and morphology can be conveniently controlled; and only high-speed air flow is used as the driving force for stretching and solvent volatilization. No high-voltage electric field, making the production process safer and the workshop management simpler;

[0025] (3) The honeycomb panel / spinning composite sound absorption structure has a wide frequency band, especially in high-frequency sound absorption. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A schematic diagram of the honeycomb panel / spinning composite sound absorption structure of Example 1 is shown.

[0027] Figure 2 A SEM diagram of the TiO2 nanofiber layer in Example 1 is shown.

[0028] Figure 3 A comparison diagram of the sound absorption test curves of the TiO2 nanofiber layers prepared in Comparative Examples 1 and 2 is shown.

[0029] Figure 4 A comparison diagram of the sound absorption test curves of the honeycomb panel / spinning composite sound absorption structure of Example 1 and the sound absorption structure prepared in Comparative Example 3 is shown.

[0030] Figure 5 A comparison diagram of the sound absorption test curves of the honeycomb panel / spinning composite sound absorption structures prepared in Examples 2-4 is shown.

[0031] Figure 6 Figure 6 shows a comparison of sound insulation test curves of the honeycomb panel / spun composite sound-absorbing structure prepared in Examples 2-4.

[0032] Figure 1 Middle: base, honeycomb panel 2, Ti02 nanofiber layer 3, perforated plate 4. DETAILED DESCRIPTION

[0033] The present application can be implemented or applied in other different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0034] It should be noted that the process equipment or device not specifically mentioned in the following examples is the conventional equipment or device in the art.

[0035] In addition, it should be understood that the one or more method steps mentioned in the present application do not exclude the presence of other method steps before and after the combination steps or the insertion of other method steps between the explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between the one or more devices / apparatuses mentioned in the present application does not exclude the presence of other devices / apparatuses before and after the combination devices / apparatuses or the insertion of other devices / apparatuses between the two explicitly mentioned devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool to identify each method step, and is not a limitation on the arrangement order of each method step or a limitation on the scope of the present application that can be implemented, and the change or adjustment of the relative relationship without substantial change of the technical content is also considered as the scope of the present application that can be implemented.

[0036] The material performance test methods in the following examples and comparative examples are as follows:

[0037] Density test: refer to JHY-S300; solid-liquid dual-purpose densimeter JHY-S300 Jinheyan.

[0038] Acoustic test: refer to Type4206-T;

[0039] Simulation test: refer to COMSOL Multiphysics 6.2.

[0040] The component substances used are all commercially available products.

[0041] The honeycomb panel in the following examples of the present application is selected from meta-aramid honeycomb core, which is purchased from Heilongjiang Zhonghexin New Material Co., Ltd.

[0042] Example 1

[0043] The present embodiment provides a preparation method of a honeycomb plate / spinning composite sound absorption structure, comprising the following steps:

[0044] S1, 0.79 g of polyvinylpyrrolidone (PVP) (4%) was dissolved in 11.25 g of anhydrous ethanol, and stirred until the solution was clear; 4 g of tetrabutyl titanate and 3.75 g of glacial acetic acid were added, and the stirring was continued until the mixed solution reached a yellow clear transparent state, obtaining a TiO2 nanospinning precursor solution;

[0045] S2, the TiO2 nanospinning precursor solution was transferred to a syringe with a coaxial needle, wherein the inner shaft needle was 28G. The TiO2 nanospinning precursor solution was uniformly injected by using a multi-channel injection pump, and the nanofiber was prepared on the lower surface of the perforated plate by airflow spinning technology. The specific airflow spinning process parameters were: the injection rate of the injection pump was 3.5 mL / h, the outlet airflow velocity of the outer shaft was 21 m / s, the distance between the needle and the collector was 15 cm, the environmental temperature was 25℃, and the indoor relative humidity was controlled at 50%;

[0046] S3, the spinning uniformly sprayed by the syringe of S2 was sprayed on the bottom surface of the perforated plate with a diameter of 30 mm until the spinning reached a thickness of 1 mm, and a TiO2 nanofiber layer was prepared; the perforated plate had a perforated diameter of 2.5 mm and a hole spacing of 0.8 mm, and then was sequentially bonded with a circular aramid honeycomb plate with a diameter of 30 mm and a solid circular iron sheet base with a diameter of 30 mm to form a closed structure, obtaining a honeycomb plate / spinning composite sound absorption structure as shown in Figure 1 .

[0047] As shown in Figure 1 , the honeycomb plate / spinning composite sound absorption structure prepared in the present embodiment is sequentially bonded from bottom to top with a base 1, a honeycomb plate 2, a TiO2 nanofiber layer 3 and a perforated plate 4.

[0048] As shown in Figure 2 , the SEM image of the TiO2 nanofiber layer in the present embodiment can be seen that the diameter of the PVP nanofiber is usually a few hundred nanometers, which makes the film or felt prepared therefrom have a very high specific surface area (surface area per unit mass or volume). When sound waves propagate, air particles will rub against the surface of these ultrafine fibers, efficiently converting sound energy into heat energy, i.e. "viscous dissipation". This is the main mechanism of high-frequency sound absorption (usually >2000 Hz).

[0049] Example 2

[0050] Example 2 differs from Example 1 in that the amount of polyvinylpyrrolidone (PVP) added in the TiO2 nanospinning precursor solution is different, specifically 1 g of polyvinylpyrrolidone PVP (5%), and the rest of the process is exactly the same.

[0051] Example 3

[0052] Example 3 differs from Example 1 in that the amount of polyvinylpyrrolidone (PVP) added in the TiO2 nanospinning precursor solution is different, specifically 1.43 g of polyvinylpyrrolidone PVP (7%), and the rest of the process is exactly the same.

[0053] Example 4

[0054] Example 4 differs from Example 1 in that the amount of polyvinylpyrrolidone (PVP) added in the TiO2 nanospinning precursor solution is different, specifically 1.88 g of polyvinylpyrrolidone PVP (9%), and the rest of the process is exactly the same.

[0055] Comparative Example 1

[0056] The present comparative example provides a preparation method of a TiO2 nanofiber layer, comprising the following steps:

[0057] S1: 0.79 g of polyvinylpyrrolidone (PVP) (4%) is dissolved in 11.25 g of anhydrous ethanol, and stirred until the solution is clear; 4 g of tetrabutyl titanate and 3.75 g of glacial acetic acid are added, and the stirring is continued until the mixed solution reaches a yellow clear transparent state, to obtain a TiO2 nanospinning precursor solution;

[0058] S2: The TiO2 nanospinning precursor solution is transferred to a syringe with a coaxial needle, wherein the inner shaft needle is 28G. The TiO2 nanospinning precursor solution is uniformly injected by using a multi-channel injection pump, and a TiO2 nanofiber layer with a thickness of 5 mm is prepared by using airflow spinning technology. The specific airflow spinning process parameters are: the injection rate of the injection pump is 3.5 mL / h, the outlet airflow velocity of the outer shaft is 21 m / s, the distance between the needle and the collector is 15 cm, the environmental temperature is 25°C, and the indoor relative humidity is controlled at 50%.

[0059] Comparative Example 2

[0060] Comparative Example 2 differs from Comparative Example 1 in that the thickness of the TiO2 nanofiber layer is different, specifically 10 mm, and the rest of the process is exactly the same.

[0061] Comparative Example 3

[0062] Comparative Example 3 differs from Example 1 in that the bottom surface of the perforated plate is not sprayed with a TiO2 nanofiber layer, and the rest of the structure is exactly the same as Example 1.

[0063] The density of the TiO2 nanofiber layer of Examples 1-4 was tested, and the results are shown in Table 1:

[0064] Table 1. Density of the TiO2 nanofiber layer of Examples 1-4 .

[0065] As can be seen from Table 1, as the PVP content in the TiO2 nanospinning precursor solution increases, the density of the prepared TiO2 nanofiber layer becomes lower and lower.

[0066] Figure 3 The sound absorption effect comparison chart of Comparative Example 1 and Comparative Example 2 is shown in Figure 1. Figure 3 As can be seen from Figure 1, the difference in sound absorption effect between the 5mm-thick nanofiber and the 10mm-thick nanofiber, and the 10mm-thick nanofiber can achieve a better sound absorption effect.

[0067] Figure 4 The sound absorption effect comparison chart of Example 1 and Comparative Example 3 is shown in Figure 2. Figure 4 As can be seen from Figure 2, the difference in sound absorption effect between the composite structure with nanofiber and the composite structure without nanofiber, and the composite structure with nanofiber can achieve a low-frequency high-sound absorption effect.

[0068] Figure 5 The sound absorption effect comparison chart of Examples 2-4 is shown in Figure 3. Figure 5 As can be seen from Figure 3, as the PVP content increases, the composite structure can achieve a high sound absorption effect at a lower frequency.

[0069] Figure 6 The sound insulation effect comparison chart of Examples 2-4 is shown in Figure 4. Figure 6 As can be seen from Figure 4, the sound insulation effect and frequency of the nanofiber with different PVP content are different.

[0070] The above examples are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea disclosed by the present application shall be covered by the claims of the present application.

Claims

1. A honeycomb panel / spun composite sound absorbing structure, characterized by, It comprises, from bottom to top, a substrate (1), a honeycomb plate (2), a TiO2 nanofiber layer (3) and a perforated plate (4) which are sequentially bonded, the thickness of the perforated plate is 0.5-0.8 mm, the aperture of the perforation in the perforated plate is 0.8-1 mm, the hole spacing of the perforation is 2.5-3 mm, and the perforation rate is 8.48-9%; the thickness of the TiO2 nanofiber layer is 0.5-1 mm, and the density is 0.016-0.024 g / cm 3 .

2. The honeycomb / silk composite sound absorbing structure according to claim 1, characterized in that: The base is a solid iron plate or a solid plastic plate with a thickness of 0.8-1 mm.

3. The honeycomb / silk composite sound absorbing structure according to claim 1, wherein: The honeycomb plate is an aramid honeycomb plate, which is uniformly distributed with a plurality of honeycomb cells, the upper surface and the lower bottom surface of the honeycomb cell are hexagonal in cross section, and the contact surface of the adjacent two honeycomb cells is completely contacted.

4. A method for manufacturing the honeycomb panel / spun composite sound absorbing structure according to any one of claims 1 to 3, characterized by: The method comprises the following steps: A TiO2 nanofiber layer is sprayed on the lower surface of the perforated plate, and then the honeycomb plate and the base are sequentially adhered to form a closed structure to obtain a honeycomb plate / spinning composite sound-absorbing structure.

5. The method of claim 4, wherein: The TiO2 nanofiber layer is prepared by airflow spinning process on the lower surface of the perforated plate using a TiO2 nanospinning precursor solution.

6. The method of claim 5, wherein: The TiO2 nanospinning precursor solution is prepared by mixing ethanol and acetic acid as a solvent, and tetrabutyl titanate and polyvinylpyrrolidone as solutes, and then heat treating the mixture.

7. The method of claim 6, wherein: The mass ratio of ethanol and acetic acid is (2-3):1; the molecular weight of polyvinylpyrrolidone is 1,300,000; the mass ratio of tetrabutyl titanate and polyvinylpyrrolidone is (3-4):1; the heat treatment temperature is 500-600°C, and the heating rate is controlled at 1-2°C / min.

8. The method of claim 6, wherein: The mass percentage of polyvinylpyrrolidone in the TiO2 nanospinning precursor solution is 4-9%.

9. The method of claim 5, wherein: The parameters of the airflow spinning process are as follows: the injection rate of the injection pump is 1.0-5.0 mL / h, the airflow velocity at the outlet of the outer shaft is 20-25 m / s, and the indoor relative humidity is controlled at 30-50%.

10. Use of the honeycomb plate / spinning composite sound-absorbing structure according to any one of claims 1-3 in the preparation of a low-frequency broadband sound-absorbing material.

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