Metamaterial honeycomb and preparation method thereof

Abstract

The invention discloses a metamaterial honeycomb and a preparation method thereof, and relates to the technical field of honeycombs, the method comprises the following steps: S1, compounding fiber cloth and an electromagnetic metamaterial functional layer to form a composite thin layer material; s2, carrying out surface treatment on the composite thin-layer material to achieve designed electrical properties; s3, the composite thin layer material subjected to surface treatment is coated with core strip glue at set intervals; s4, laminating the composite thin-layer material coated with the core strip glue layer by layer to form a laminated block; s5, performing hot-pressing curing on the stacked blocks; s6, stretching the cured stacked block to form a metamaterial honeycomb structure; s7, heating and shaping the metamaterial honeycomb structure; and S8, carrying out gum dipping and curing on the shaped metamaterial honeycomb structure to obtain the metamaterial honeycomb. According to the technical scheme, the process is simple, the density of the wave-absorbing honeycomb and the weight of functional structural parts can be greatly reduced while the excellent wave-absorbing performance is achieved, and the cost-effectiveness ratio of an aircraft is increased.

Description

Technical Field

[0001] This invention relates to the field of cellular technology, and more specifically, to a metamaterial cellular structure and its preparation method. Background Technology

[0002] Currently, there are two main types of implementation methods for absorbing cell structures.

[0003] The first type uses aramid paper honeycomb as a base to prepare a honeycomb core material, and then impregnates the honeycomb core material with a microwave absorbing agent to obtain a microwave absorbing honeycomb. The disadvantage of this type of microwave absorbing honeycomb preparation method is that due to the influence of factors such as thickness and gravity, it is difficult to achieve precise gradient honeycomb electromagnetic parameter design, which is not conducive to impedance matching and thus affects the microwave absorption performance.

[0004] The second type is ceramic-based honeycomb, which mainly uses 3D printing to realize the gradient honeycomb superstructure of SiC ceramic materials. The disadvantage of this type of ceramic-based honeycomb is that the process is very complex, the manufacturing cost is high, the manufacturing cycle is long, and it is difficult to achieve large-scale promotion and application.

[0005] Therefore, simplifying the process while ensuring improved cellular absorption performance and achieving large-scale application has always been a goal that the industry urgently needs to improve. Summary of the Invention

[0006] The main objective of this invention is to provide a metamaterial honeycomb and its preparation method, so as to solve the technical problem in the prior art of how to simplify the process flow to achieve large-scale application while ensuring improved honeycomb wave absorption performance.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a method for preparing a metamaterial honeycomb is provided, comprising the following steps: S1, composite the fiber cloth with the electromagnetic metamaterial functional layer to form a composite thin-layer material; S2, The composite thin-layer material is surface-treated to achieve the designed electrical properties; S3, core strip adhesive with a set spacing is applied to the composite thin layer material after surface treatment; S4, the composite thin-layer material coated with the core strip adhesive is stacked layer by layer to form a stack; S5, the stack is hot-pressed and cured; S6, stretch the cured stack to form a metamaterial honeycomb structure; S7, The metamaterial honeycomb structure is heated and shaped; S8, the shaped metamaterial honeycomb structure is impregnated and cured with resin to obtain the metamaterial honeycomb.

[0008] Further, in step S1, the fiber cloth includes one of glass fiber cloth, quartz fiber cloth, ceramic-based inorganic fiber cloth, and polyimide fiber paper. The fiber cloth is in the form of plain weave, twill weave, or satin weave, and the gap between the warp and weft directions of the fiber cloth is ≤0.05mm.

[0009] Further, in step S2, the surface treatment includes heating and dehumidifying the composite thin film material, plasma treatment, and surface coating modification treatment, and the transmittance of the composite thin film material at a frequency of 10 GHz is -0.1 dB to -30 dB after coating.

[0010] Further, in step S3, the width of the core strip adhesive is 0.6 to 1.0 times the side length of the preset honeycomb hole, and the core strip adhesive is one of modified epoxy resin, modified polyimide resin, modified phenolic cyanate resin, modified cyano resin, and modified benzocyclobutene resin.

[0011] Furthermore, in step S4, the layer-by-layer lamination includes laminating the core strip adhesive of two adjacent composite thin-layer materials at equal intervals and with staggered spacing.

[0012] Further, in step S5, the hot-press curing includes placing the stack into a hot press or autoclave, heating and pressurizing it, and curing the core strip adhesive, wherein the heating temperature is 180℃-300℃ and the pressure is 0.1MPa-10MPa.

[0013] Further, in step S6, the stretching includes fixing the stack and stretching it using a stretching machine and auxiliary tooling, so that the cured stack forms a hexagonal metamaterial honeycomb structure in the thickness direction of the stack.

[0014] Further, in step S7, the heating and shaping includes placing the metamaterial honeycomb structure together with the shaping auxiliary tooling into an oven and heating it to 180~300°C to shape the honeycomb structure pores within the metamaterial honeycomb structure.

[0015] Further, in step S8, the impregnation and curing includes impregnating the shaped metamaterial honeycomb structure with phenolic resin, cyanate ester resin, or polyimide resin to achieve a preset required density, and then heating and curing the impregnated honeycomb structure to obtain the metamaterial honeycomb.

[0016] According to a second aspect of the present invention, a metamaterial honeycomb is provided, which is prepared by the above-described preparation method.

[0017] The preparation method disclosed in this invention uses fiber cloth as the backbone material of the honeycomb, which is then combined with an electromagnetic metamaterial functional layer to form a composite thin-layer material. The surface of the composite thin-layer material is treated to give it the desired electrical properties. Then, steps such as coating, lamination, pressing, stretching, shaping, impregnation, and curing are performed to achieve the target density, resulting in a high-temperature resistant absorbing fiber cloth honeycomb, i.e., a metamaterial honeycomb. This method has a simple process, low manufacturing cost, and is suitable for large-scale application. This method can prepare a high-temperature resistant absorbing fiber cloth honeycomb with excellent absorption performance over a wide frequency range, effectively solving the technical problem in the prior art of how to ensure improved honeycomb absorption performance while simplifying the process to achieve large-scale application. Moreover, the metamaterial honeycomb prepared by the above method can significantly reduce the density of the absorbing honeycomb while increasing the compressive strength at the same density, which can significantly reduce the weight of the functional structural components of the aircraft, improve the cost-effectiveness of the aircraft, and also have high temperature resistance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the steps involved in the preparation of metamaterial honeycomb in an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the stacking of hexagonal honeycomb lattice in an embodiment of the present invention.

[0020] Figure 3 This is a physical image of the metamaterial honeycomb structure of twill glass fiber cloth in Embodiment 3 of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0023] As described in the background section of this invention, there is a technical problem in the prior art regarding how to simplify the process while ensuring improved cell microwave absorption performance to achieve large-scale application. To solve this problem, in a typical embodiment of this invention, a method for preparing metamaterial cellars is provided, the steps of which are illustrated in the schematic diagram below. Figure 1 As shown, it includes the following steps: S1, composite the fiber cloth with the electromagnetic metamaterial functional layer to form a composite thin-layer material; S2, The composite thin-layer material is surface-treated to achieve the designed electrical properties; S3, core strip adhesive with a set spacing is applied to the composite thin layer material after surface treatment; S4, the composite thin-layer material coated with the core strip adhesive is stacked layer by layer to form a stack; S5, the stack is hot-pressed and cured; S6, stretch the cured stack to form a metamaterial honeycomb structure; S7, The metamaterial honeycomb structure is heated and shaped; S8, the shaped metamaterial honeycomb structure is impregnated and cured with resin to obtain the metamaterial honeycomb.

[0024] The method described in this invention uses fiber cloth as the backbone material of a honeycomb structure, which is then combined with an electromagnetic metamaterial functional layer to form a composite thin-layer material. The surface of the composite thin-layer material is treated to impart specific electrical properties. Following this, steps such as coating, lamination, pressing, stretching, shaping, impregnation, and curing are performed to achieve the target density, resulting in a high-temperature resistant absorbing fiber cloth honeycomb, i.e., a metamaterial honeycomb. This method is simple, has low manufacturing costs, and is suitable for large-scale application. It can produce high-temperature resistant metamaterial honeycombs with excellent absorption performance over a wide frequency range, effectively solving the technical problem in existing technologies of how to ensure improved honeycomb absorption performance while simplifying the process for large-scale application.

[0025] In step S1, the fiber cloth is composited with the electromagnetic metamaterial functional layer to form a composite thin-layer material. In step S1, the fiber cloth includes one of glass fiber cloth, quartz fiber cloth, ceramic-based inorganic fiber cloth, and polyimide fiber paper. The fiber cloth is in the form of plain weave, twill weave, or satin weave, and the warp and weft gaps of the fiber cloth are both ≤0.05mm.

[0026] Currently, in existing technologies, microwave absorbing materials are generally ferromagnetic materials, mainly including ferrite coatings, polycrystalline iron fibers, metal micropowders, and carbon nanotube composites. These ferromagnetic materials are characterized by high density. When these ferromagnetic materials are used to make microwave absorbing honeycombs, the density of the honeycomb increases by more than 100%, which is detrimental to the weight reduction of aircraft. However, the preparation method of this invention does not use ferromagnetic materials as raw materials for preparing microwave absorbing materials. Instead, it uses fiber cloth as the backbone material of the honeycomb and combines it with the electromagnetic metamaterial functional layer to form a composite thin-layer material. This composite thin-layer material has the advantage of low density. Using it as the raw material for preparing metamaterial honeycombs can significantly reduce the density of the prepared metamaterial honeycomb, thereby significantly reducing the weight of the functional structural components of the aircraft and improving the cost-effectiveness of the aircraft. Moreover, using fiber cloth as the backbone material for preparing metamaterial honeycombs can also increase the compressive strength at the same density.

[0027] In this embodiment, the electromagnetic metamaterial functional layer has a large number of pre-designed metamaterial microstructures. The wave absorption performance of the metamaterial honeycomb can be designed over a wide range through the metamaterial microstructures, achieving broadband wave absorption. Moreover, its overall performance is superior to that of conventional wave-absorbing honeycombs in the prior art.

[0028] In this embodiment, the fiber cloth is composited with an electromagnetic metamaterial functional layer to form a composite thin-layer material. The resulting metamaterial honeycomb, obtained after subsequent steps S2-S8, possesses electromagnetic modulation capabilities. This is because the numerous metamaterial microstructures designed on the electromagnetic metamaterial functional layer ultimately form on the honeycomb sidewalls. Through the ultra-large-scale design of these metamaterial microstructures, electromagnetic modulation functionality is achieved. Specifically, designing the warp and weft gaps of the fiber cloth to be ≤0.05mm allows for better implementation of electromagnetic modulation, ensuring broadband wave absorption functionality.

[0029] In step S2, the composite thin-film material undergoes surface treatment to achieve the designed electrical properties. This surface treatment includes heating and dehumidifying the composite thin-film material, plasma treatment, and surface coating modification treatment. After coating, the transmittance of the composite thin-film material at a 10 GHz frequency is -0.1 dB to -30 dB.

[0030] In this embodiment, the composite thin-film material is first subjected to heat dehumidification treatment, then plasma treatment, and finally surface coating modification treatment. After this series of treatments, it acquires the designed electrical properties. In step S3, a core strip adhesive with a predetermined spacing is coated onto the surface-treated composite thin-layer material. In step S3, the width of the core strip adhesive is 0.6 to 1.0 times the side length of the predetermined honeycomb cells, and the core strip adhesive is one of modified epoxy resin, modified polyimide resin, modified phenolic cyanate resin, modified cyano resin, or modified benzocyclobutene resin.

[0031] In this embodiment, the core adhesive is selected from one of modified epoxy resin, modified polyimide resin, modified phenolic cyanate resin, modified cyano resin, and modified benzocyclobutene resin, which has high temperature resistance properties, so that the core adhesive can be a high temperature resistant core adhesive.

[0032] In step S4, the composite thin-layer material coated with the core adhesive is stacked layer by layer to form a stack. In step S4, the layer-by-layer stacking includes stacking adjacent layers of composite thin-layer material with the core adhesive evenly spaced and staggered.

[0033] In step S5, the stack is subjected to hot-press curing. In step S5, the hot-press curing includes placing the stack in a hot press or autoclave, heating and pressurizing it, and curing the core adhesive. The heating temperature is 180℃-300℃, and the pressure is 0.1MPa-10MPa.

[0034] In this embodiment, under the conditions of heating temperature of 180℃-300℃ and pressure of 0.1MPa-10MPa, the core strip adhesive can be better cured by hot pressing, preventing cracking.

[0035] In step S6, the cured stack is stretched to form a metamaterial honeycomb structure. In step S6, the stretching includes fixing the stack and stretching it using a stretching machine and auxiliary tooling, so that the cured stack forms a hexagonal metamaterial honeycomb structure in the thickness direction of the stack.

[0036] In this embodiment, if the pre-designed honeycomb lattice is hexagonal, then a hexagonal metamaterial honeycomb structure will be formed during the stretching in step S6. If the pre-designed honeycomb lattice is rectangular, then a rectangular metamaterial honeycomb structure will be formed during the stretching in step S6. If the pre-designed honeycomb lattice is of other shapes, then a metamaterial honeycomb structure of the corresponding shape will be formed during the stretching in step S6. No limitation is made here.

[0037] In step S7, the metamaterial honeycomb structure is heated and shaped. Specifically, in step S7, the heating and shaping involves placing the metamaterial honeycomb structure, along with shaping auxiliary fixtures, into an oven and heating it to 180-300°C to shape the honeycomb pores within the metamaterial honeycomb structure.

[0038] In this embodiment, heating to 180~300℃ can better shape the honeycomb structure lattice, achieving the goal of firm shaping.

[0039] In step S8, the shaped metamaterial honeycomb structure is impregnated and cured to obtain the metamaterial honeycomb. Specifically, in step S8, the impregnation and curing includes impregnating the shaped metamaterial honeycomb structure with phenolic resin, cyanate ester resin, or polyimide resin to achieve a predetermined desired density, and then heating and curing the impregnated honeycomb structure to obtain the metamaterial honeycomb.

[0040] In this embodiment, the preset honeycomb density range is 30 kg / m³. 3 ~200Kg / m 3 This range has the advantage of light density, which is the same as that of ordinary fiber cloth honeycomb. It can better achieve the goal of significantly reducing the weight of functional structural components of aircraft, thereby helping to improve the cost-effectiveness of aircraft.

[0041] In this embodiment, the impregnation in step S8 involves removing the shaping auxiliary tooling and impregnating the honeycomb pores within the already shaped metamaterial honeycomb structure with phenolic resin, cyanate ester resin, or polyimide resin, until the honeycomb density reaches 30 kg / m³. 3 ~200Kg / m 3 After reaching the preset honeycomb density range, the impregnation step is completed, and a curing step is performed. The impregnated honeycomb structure is heated and cured to obtain the metamaterial honeycomb. The metamaterial honeycomb thus produced has high temperature resistance. In this embodiment, the target density range of the honeycomb can be achieved with a single impregnation in step S8, without the need for secondary impregnation. Compared with the prior art, which requires secondary impregnation during the manufacturing process of microwave absorbing honeycomb, the present invention reduces the number of process steps. Moreover, the secondary impregnation process generates a large amount of organic waste gas, which pollutes the environment. The density uniformity of secondary impregnation is difficult to control, which means that there will be a large deviation in the performance in the T direction. However, the preparation method of the present invention does not have these defects of the prior art. The target density range of the honeycomb can be achieved with only a single impregnation in step S8, which not only reduces the emission of organic waste gas and reduces environmental pollution, but also enhances the control of density uniformity.

[0042] In this embodiment, the impregnating adhesive used in step S8 is phenolic resin, cyanate ester resin, or polyimide resin, which has the advantage of strong process compatibility.

[0043] In this embodiment, the fiber cloth is empowered from the source. The fiber cloth is combined with an electromagnetic metamaterial functional layer on the surface of the fiber cloth to form a composite thin-layer material. After the improvement, while achieving excellent wave absorption performance and high temperature mechanical retention rate, the density of the honeycomb can be significantly reduced, while increasing the compressive strength at the same density. This can significantly reduce the weight of the functional structural components of the aircraft, improve the cost-effectiveness of the aircraft, and also have high temperature resistance.

[0044] Example 1 S1, a composite thin-film material is formed by combining plain-weave quartz fiber cloth with an electromagnetic metamaterial functional layer. The plain-weave quartz fiber cloth has a width of 1000 mm and a thickness of 0.1 mm. The gap between the warp and weft directions of the plain-weave quartz fiber cloth is ≤0.050 mm. S2, after heating and dehumidifying the composite thin-layer material and plasma treatment, a metal film is deposited on the surface of the plain quartz fiber cloth to achieve modification treatment, and the transmittance of the plain quartz fiber cloth at 10GHz frequency is -20dB±5dB after coating. S3, a core strip of modified epoxy resin with a spacing of 7.32 mm is coated on the surface of the plain weave quartz fiber cloth, and the width of the core strip is 1.3~1.4 mm. S4, the plain-weave quartz fiber cloth coated with the core strip adhesive is arranged as follows: Figure 2 As shown, layers are staggered and stacked to form a stacked block. Figure 2 In the text, 1 indicates the location of the core strip adhesive, and 2 indicates the fiber cloth after the core strip adhesive has been applied. S5. Place the stack into a hot press or autoclave and heat and pressurize it to cure the core strip adhesive. The pressure is 0.3MPa and the maximum curing temperature is 180~200℃. S6. Rotate the cured stack by 90° and stretch it using a stretching machine and auxiliary tooling to form a hexagonal metamaterial honeycomb structure in the thickness direction of the cured laminate. S7. Place the above-mentioned hexagonal metamaterial honeycomb structure along with the shaping auxiliary tooling into an oven and heat it to 250°C to shape the pores of the metamaterial honeycomb structure. S8. The shaped metamaterial honeycomb structure is removed using a shaping auxiliary tooling and impregnated with phenolic resin. After reaching the preset honeycomb density range, a curing step is performed, in which the impregnated honeycomb block is placed in an oven for room temperature heating and curing, with a maximum heating temperature of 180℃. After curing, the metamaterial honeycomb is obtained.

[0045] The metamaterial honeycomb obtained through steps S1-S8 above was sampled and tested. The density of the honeycomb blocks was 95 kg / m³. 3 The compressive strength at room temperature is 3.46 MPa / m. 3The mechanical retention rate at 300℃ is 72.1%, and the radar cross section (RCS) test results in the 2~18GHz frequency range are below -5~-10dB. In this embodiment, the honeycomb is formed in one step without secondary impregnation, the mechanical retention rate at 300℃ is above 70%, broadband absorption is achieved using low-cost materials, and high mechanical retention rate is maintained at high temperatures.

[0046] Example 2 S1, a composite thin-film material is formed by combining plain-weave quartz fiber cloth with an electromagnetic metamaterial functional layer. The plain-weave quartz fiber cloth has a width of 500 mm and a thickness of 0.08 mm. The gap between the warp and weft directions of the plain-weave quartz fiber cloth is ≤0.020 mm. S2, after heating and dehumidifying the composite thin-layer material and plasma treatment, a metal film is deposited on the surface of the plain quartz fiber cloth to achieve modification treatment. After the coating, the plain quartz fiber cloth maintains the same weft direction and changes the warp direction according to the set parameters. Its transmittance at 10GHz frequency changes from -0.1dB to -20dB. S3, a core strip adhesive of modified phenolic cyanate resin with a spacing of 4 mm is coated on the surface of the above plain quartz fiber cloth, and the width of the core strip adhesive is 0.8~1.0 mm. S4, the plain-weave quartz fiber cloth coated with the core strip adhesive is arranged as follows: Figure 2 As shown, layers are staggered and stacked to form a stacked block; S5. Place the stack into a hot press or autoclave and heat and pressurize it to cure the core strip adhesive. The pressure is 0.3MPa and the maximum curing temperature is 200~220℃. S6. Rotate the cured stack by 90° and stretch it using a stretching machine and auxiliary tooling to form a hexagonal metamaterial honeycomb structure in the thickness direction of the cured laminate. S7. The above-mentioned hexagonal metamaterial honeycomb structure, together with the shaping auxiliary tooling, is placed in an oven and heated to 260°C to shape the pores of the metamaterial honeycomb structure. S8. The shaped metamaterial honeycomb structure is removed using a shaping auxiliary tooling and impregnated with cyanate ester resin. After reaching the preset honeycomb density range, a curing step is performed, in which the impregnated honeycomb block is placed in an oven for room temperature heating and curing, with a maximum heating temperature of 210℃. After curing, the metamaterial honeycomb is obtained.

[0047] The metamaterial honeycomb obtained through steps S1-S8 above was sampled and tested. The density of the honeycomb blocks was 95±10 kg / m³. 3 Compressive strength at room temperature: 3.2 MPa / m 3The mechanical retention rate at 300℃ is 76.5%, and the radar cross section (RCS) test results in the 2~18GHz frequency range are below -10dB. In this embodiment, the honeycomb is formed in one step without secondary impregnation, the mechanical retention rate at 300℃ is above 70%, broadband wave absorption is achieved using low-cost materials, and high mechanical retention rate is maintained at high temperatures.

[0048] Example 3 S1, a composite thin-film material is formed by combining twill fiberglass cloth with an electromagnetic metamaterial functional layer. The twill fiberglass cloth has a width of 1000 mm and a thickness of 0.2 mm. The gap between the warp and weft directions of the twill fiberglass cloth is ≤0.010 mm. S2, after heating and dehumidifying the composite thin-layer material and plasma treatment, a metal film is deposited on the surface of the twill glass fiber cloth to achieve modification treatment. After coating, the twill glass fiber cloth remains consistent in the weft direction and changes in the warp direction according to the set parameters. Its transmittance at 10GHz frequency changes from -0.1dB to -15dB. S3, a core strip adhesive of modified polyimide resin with a spacing of 15 mm is coated on the surface of the above-mentioned twill fiberglass cloth, and the width of the core strip adhesive is 3.2~3.5 mm. S4, the twill glass fiber cloth coated with the core strip adhesive is arranged as follows: Figure 2 As shown, layers are staggered and stacked to form a stacked block; S5. Place the stack into a hot press or autoclave and heat and pressurize it to cure the core strip adhesive. The pressure is 0.6MPa and the maximum curing temperature is 260℃. S6. Rotate the cured stack by 90° and stretch it using a stretching machine and auxiliary tooling to form a hexagonal metamaterial honeycomb structure in the thickness direction of the cured laminate. S7. The above-mentioned hexagonal metamaterial honeycomb structure, together with the shaping auxiliary tooling, is placed in an oven and heated to 257°C to shape the pores of the metamaterial honeycomb structure. S8. The shaped metamaterial honeycomb structure is removed using a shaping auxiliary tooling and impregnated with modified polyimide resin. After reaching the preset honeycomb density range, a curing step is performed, in which the impregnated honeycomb block is placed in an oven for room temperature heating and curing, with a maximum heating temperature of 280℃. After curing, the metamaterial honeycomb is obtained.

[0049] The metamaterial honeycomb obtained through steps S1-S8 above was sampled and tested. The density of the honeycomb blocks was 94 kg / m³. 3 The compressive strength at room temperature is 4.87 MPa / m. 3The mechanical retention rate at 300℃ is 75.2%, and the radar cross section (RCS) test results in the 2~18GHz frequency range are below -10dB. In this embodiment, the honeycomb is formed in one step without secondary impregnation, the mechanical retention rate at 300℃ is above 70%, broadband wave absorption is achieved using low-cost materials, and high mechanical retention rate is maintained at high temperatures.

[0050] Please see Figure 3 The image shown is a physical diagram of the metamaterial honeycomb structure of twill glass fiber cloth in Embodiment 3 of the present invention.

[0051] like Figure 3 As shown, the pore side length of the metamaterial honeycomb structure containing twill fiberglass cloth is 1.83 mm.

[0052] In this embodiment of the invention, fiber cloth is used as the backbone material of the honeycomb structure and is composited with an electromagnetic metamaterial functional layer to form a composite thin-layer material. The surface of the composite thin-layer material is treated to give it the set electrical properties. Then, steps such as coating, lamination, pressing, stretching, shaping, impregnation, and curing are performed to achieve the target density, resulting in a high-temperature resistant absorbing fiber cloth honeycomb, i.e., a metamaterial honeycomb. This solution has a simple process, low manufacturing cost, and is suitable for large-scale application. This solution can prepare a high-temperature resistant absorbing fiber cloth honeycomb with excellent absorption performance over a wide frequency range. It effectively solves the technical problem in the prior art of how to ensure improved honeycomb absorption performance while simplifying the process to achieve large-scale application. Moreover, the metamaterial honeycomb prepared by the above method can significantly reduce the density of the absorbing honeycomb while increasing the compressive strength at the same density. This can significantly reduce the weight of the functional structural components of the aircraft, improve the cost-effectiveness of the aircraft, and also has high temperature resistance.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing metamaterial honeycomb, characterized in that, Includes the following steps: S1, composite the fiber cloth with the electromagnetic metamaterial functional layer to form a composite thin-layer material; S2, The composite thin-layer material is surface-treated to achieve the designed electrical properties; S3, core strip adhesive with a set spacing is applied to the composite thin layer material after surface treatment; S4, the composite thin-layer material coated with the core strip adhesive is stacked layer by layer to form a stack; S5, the stack is hot-pressed and cured; S6, stretch the cured stack to form a metamaterial honeycomb structure; S7, The metamaterial honeycomb structure is heated and shaped; S8, the shaped metamaterial honeycomb structure is impregnated and cured with resin to obtain the metamaterial honeycomb.

2. The preparation method according to claim 1, characterized in that, In step S1, the fiber cloth includes one of glass fiber cloth, quartz fiber cloth, ceramic-based inorganic fiber cloth, and polyimide fiber paper. The fiber cloth is in the form of plain weave, twill weave, or satin weave, and the gap between the warp and weft directions of the fiber cloth is ≤0.05mm.

3. The preparation method according to claim 1, characterized in that, In step S2, the surface treatment includes heating and dehumidifying the composite thin film material, plasma treatment, and surface coating modification treatment, and the transmittance of the composite thin film material at a frequency of 10 GHz is -0.1 dB to -30 dB after coating.

4. The preparation method according to claim 1, characterized in that, In step S3, the width of the core strip adhesive is 0.6 to 1.0 times the side length of the preset honeycomb holes, and the core strip adhesive is one of modified epoxy resin, modified polyimide resin, modified phenolic cyanate resin, modified cyano resin, and modified benzocyclobutene resin.

5. The preparation method according to claim 1, characterized in that, In step S4, the layer-by-layer stacking includes stacking the core strip adhesive of two adjacent composite thin-layer materials at equal intervals and staggered positions.

6. The preparation method according to claim 1, characterized in that, In step S5, the hot-press curing includes placing the stack into a hot press or autoclave, heating and pressurizing it, and curing the core strip adhesive, wherein the heating temperature is 180℃-300℃ and the pressure is 0.1MPa-10MPa.

7. The preparation method according to claim 1, characterized in that, In step S6, the stretching includes fixing the stack and stretching it using a stretching machine and auxiliary tooling, so that the cured stack forms a hexagonal metamaterial honeycomb structure in the thickness direction of the stack.

8. The preparation method according to claim 1, characterized in that, In step S7, the heating and shaping includes placing the metamaterial honeycomb structure along with the shaping auxiliary tooling into an oven and heating it to 180~300℃ to shape the honeycomb structure pores within the metamaterial honeycomb structure.

9. The preparation method according to claim 1, characterized in that, In step S8, the impregnation and curing process includes impregnating the shaped metamaterial honeycomb structure with phenolic resin, cyanate ester resin, or polyimide resin to achieve a preset required density, and then heating and curing the impregnated honeycomb structure to obtain the metamaterial honeycomb.

10. A metamaterial honeycomb, characterized in that, Prepared by the preparation method according to any one of claims 1 to 9.

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