C-shaped composite wave-absorbing structure and preparation method thereof

Abstract

The invention provides a C-shaped composite wave-absorbing structure and a preparation method thereof, and belongs to the technical field of wave-absorbing materials.The preparation method of the C-shaped composite wave-absorbing structure comprises the steps that S1, according to the performance requirement of the C-shaped composite wave-absorbing structure, a carbon fiber prepreg, a wave-absorbing prepreg and a wave-transmitting prepreg are laid, and the laid prepreg is obtained; s2, a pressure equalizing plate is laid on the outer side of the laid prepreg, then first curing forming is carried out, a demolding material is removed, and a carbon fiber layer, a wave absorbing layer and a wave transmitting layer are obtained; a demolding material is laid between the laid prepreg and the pressure equalizing plate; and S3, sequentially compounding the carbon fiber layer, the wave absorbing layer and the wave transparent layer to obtain the C-shaped composite wave absorbing structure. According to the preparation method of the C-shaped composite wave-absorbing structure, the appearance deformation amount of the wave-absorbing structure in the forming process can be effectively controlled, the forming precision is high, and the preparation method can be used for preparing large complex wave-absorbing structures and has good application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of wave absorbing materials, and in particular to a C-shaped composite wave absorbing structure and a preparation method thereof. Background Art

[0002] In order to achieve the requirements of reducing manufacturing costs and facilitating assembly, the C-shaped structure is currently a more commonly used structure for target rotating body components. While reducing the cost and cycle of rotating body fiber laying molding, it is convenient for the installation of other supporting devices inside the component. Traditional C-shaped structures mostly use autoclave molding process. Due to the mismatch of thermal expansion coefficients between the matrix and the fiber or chemical shrinkage during the curing process, stress is formed inside the component, and the residual stress is released through deformation in the final demolding stage, causing structural deformation, affecting the dimensional accuracy of the parts and the assembly of the structure. In order to overcome the various problems caused by residual stress and deformation during the curing process, the traditional method is to repeatedly adjust and compensatory correct processing of the curing process specifications of the structural parts and the mold surface used for curing of the structural parts based on experience and process tests to control the degree of deformation or offset the influence of deformation. However, this processing method consumes a lot of manpower and material resources and is not suitable for large and complex structures.

[0003] The C-shaped absorbing structure is a new requirement for low-scattering targets for rotating body parts. In addition to the structural strength and dimensional tolerance requirements, it also takes into account the radar wave absorption function. In addition to the various prepregs required for the traditional C-shaped structure, the C-shaped absorbing structure also needs to include absorbing prepregs containing absorbents. Multiple materials with different thermal expansion coefficients will cause asymmetry in the ply, which will make it difficult to control deformation and stress during the molding and curing process and maintain the shape, resulting in the inevitable deformation of the absorbing structure after curing. Summary of the invention

[0004] In view of one or more technical problems existing in the prior art, the present invention provides a C-shaped composite absorbing structure and a preparation method thereof. The preparation method of the C-shaped composite absorbing structure provided by the present invention is simple to operate, high in efficiency, and low in cost. It can effectively control the shape deformation of the absorbing structure during the molding process, has high molding accuracy, can be used for the preparation of large and complex absorbing structures, and has good application prospects.

[0005] In a first aspect, the present invention provides a method for preparing a C-shaped composite absorbing structure, the method comprising:

[0006] S1. According to the performance requirements of the C-shaped composite absorbing structure, the carbon fiber prepreg, the absorbing prepreg and the transparent prepreg are layered to obtain a layered prepreg; the layered prepreg includes the carbon fiber prepreg, the absorbing prepreg and the transparent prepreg from the inside to the outside; a release material is laid between the carbon fiber prepreg and the absorbing prepreg and between the absorbing prepreg and the transparent prepreg;

[0007] S2. Laying a pressure plate on the outside of the prepreg after the layering, and then performing a first curing molding, removing the release material, to obtain a carbon fiber layer, an absorbing layer and a wave-transmitting layer; a release material is laid between the prepreg after the layering and the pressure plate;

[0008] S3. Compounding the carbon fiber layer, the wave absorbing layer and the wave transparent layer in sequence to obtain a C-shaped composite wave absorbing structure.

[0009] Preferably, the method for preparing the microwave absorbing prepreg comprises: distributing the microwave absorbing slurry on the surface of the substrate, and drying to obtain the microwave absorbing prepreg;

[0010] The microwave absorbing slurry comprises an absorbent, a resin, an auxiliary agent and a solvent.

[0011] Preferably, the absorbent is a magnetic absorbent, preferably one or more of carbonyl iron powder, ferrite, and sendust;

[0012] The resin is an epoxy resin, preferably a medium-temperature epoxy resin;

[0013] The auxiliary agent includes at least one of glass microspheres and a co-solvent, preferably, the co-solvent is at least one of xylene and n-butanol; and / or

[0014] The solvent is ethyl acetate.

[0015] Preferably, the wave-transmitting prepreg is a low-dielectric prepreg, preferably one or more of quartz fiber cloth / epoxy resin prepreg, glass fiber cloth / epoxy resin prepreg, and aramid fiber cloth / epoxy resin prepreg.

[0016] Preferably, the raw materials for preparing the pressure balancing plate include glass fiber prepreg and Airpad rubber.

[0017] Preferably, the preparation method of the pressure equalizing plate includes: laying glass fiber prepreg and Airpad rubber on the surface of the substrate in sequence, and obtaining the pressure equalizing plate through a second curing molding; the size of the substrate is consistent with the size of the C-shaped composite absorbing structure; preferably, the second curing molding adopts an autoclave molding process.

[0018] Preferably, step S4 comprises: sequentially bonding the carbon fiber layer, the wave absorbing layer and the wave transparent layer with an adhesive film, and then performing a third curing process to obtain a C-shaped composite wave absorbing structure.

[0019] Preferably, the resin system used in the adhesive film is the same as the resin system used in the carbon fiber prepreg, the microwave absorbing prepreg and the microwave transmitting prepreg.

[0020] Preferably, the first curing molding adopts an autoclave molding process; and / or

[0021] The third curing molding adopts a hot-pressing molding process.

[0022] The present invention provides a C-shaped composite wave absorbing structure in a second aspect, which is prepared by the preparation method described in the first aspect.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] During the plying process of the present invention, demoulding materials are laid between the layers, and physical means are used to isolate the layers of materials with different thermal expansion coefficients, which can reduce the stress release between the layers during the curing process, control the deformation, and achieve high molding precision, thus solving the problems of large deformation, difficult shape control, difficult assembly, and long cycle in the traditional autoclave molding process for forming C-shaped composite absorbing structures. Laying an equalizing plate on the outside of the prepreg after plying and then performing curing molding can increase the compactness and airtightness during the molding process and improve the molding quality of the outer surface of the C-shaped composite absorbing structure. Compounding the layers after molding can ensure that both structural strength and absorbing performance are taken into account while ensuring the control of deformation.

[0025] The preparation method of the C-shaped composite absorbing structure provided by the present invention is simple to operate, highly efficient, and low in cost. It can effectively control the deformation of the shape of the absorbing structure during the molding process, has high molding precision, and can be used for the preparation of large and complex absorbing structures, and has good application prospects. The C-shaped composite absorbing structure prepared by the preparation method of the present invention has both structural strength and absorbing performance on the basis of ensuring a small deformation, and can meet the use requirements of low-scattering target rotating body components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a flow chart of the method for preparing the C-shaped composite wave absorbing structure provided by the present invention;

[0028] Figure 2 It is a structural schematic diagram of a C-shaped composite wave absorbing structure provided by the present invention;

[0029] Figure 3 2 is a schematic diagram of film adhesion inspection of a C-shaped composite wave absorbing structure provided in Example 1 of the present invention;

[0030] Figure 4 It is a schematic diagram of the film adhesion test of the C-shaped composite absorbing structure provided in Comparative Example 1 of the present invention.

[0031] Reference numerals:

[0032] 11-carbon fiber layer; 12-wave absorbing layer; 13-wave transmitting layer. DETAILED DESCRIPTION

[0033] In order to make the purpose, 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. 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 making creative work are within the scope of protection of the present invention.

[0034] like Figure 1 In a first aspect, the present invention provides a method for preparing a C-shaped composite absorbing structure, the method comprising:

[0035] S1. According to the performance requirements of the C-shaped composite absorbing structure, the carbon fiber prepreg, the absorbing prepreg and the transparent prepreg are layered to obtain a layered prepreg; the layered prepreg includes the carbon fiber prepreg, the absorbing prepreg and the transparent prepreg from the inside to the outside; a release material is laid between the carbon fiber prepreg and the absorbing prepreg and between the absorbing prepreg and the transparent prepreg;

[0036] S2. Laying a pressure plate on the outside of the prepreg after the layering, and then performing a first curing molding, removing the release material, to obtain a carbon fiber layer, an absorbing layer and a wave-transmitting layer; a release material is laid between the prepreg after the layering and the pressure plate;

[0037] S3. Compounding the carbon fiber layer, the wave absorbing layer and the wave transparent layer in sequence to obtain a C-shaped composite wave absorbing structure.

[0038] It should be noted that the outer side refers to the side of the wave-transmitting layer in the C-shaped composite wave-absorbing structure. The laying order of each layer in the laying process can be adjusted according to the mold used. If a positive mold is used, the laying order is carbon fiber prepreg, wave-absorbing prepreg, and wave-transmitting prepreg; if a negative mold is used, the laying order is wave-absorbing prepreg, wave-transmitting prepreg, and carbon fiber prepreg.

[0039] The innermost layer (carbon fiber layer) of the absorbing structure of the present invention adopts carbon fiber prepreg, the middle layer (absorbing layer) adopts various types of absorbing prepregs, and the outermost layer (transparent layer) needs to meet impedance matching for wave transmission processing, such as low dielectric prepregs (for example, quartz fiber prepreg, glass fiber prepreg, aramid fiber prepreg, etc.). The asymmetry of the ply and the difference in thermal expansion coefficients of each layer increase the difficulty of controlling deformation and stress during the curing process, resulting in the absorbing structure being deformed after curing. Therefore, during the plying process of the present invention, a demoulding material is laid between the layers, and the layers of materials with different thermal expansion coefficients are isolated by physical means, which can reduce the stress release between the layers during the curing process, the deformation amount is controllable, and the molding accuracy is high, which solves the problems of large deformation, difficult shape control, and long assembly cycle in the traditional autoclave molding process of forming a C-shaped composite absorbing structure. Laying an equalizing plate on the outside of the prepreg after plying and then curing and molding can increase the compactness and airtightness during the molding process and improve the molding quality of the outer surface of the C-shaped composite absorbing structure. By compounding the formed layers, both structural strength and wave-absorbing performance can be taken into account while ensuring the control of deformation.

[0040] The preparation method of the C-shaped composite absorbing structure provided by the present invention is simple to operate, highly efficient, and low in cost. It can effectively control the deformation of the shape of the absorbing structure during the molding process, has high molding precision, and can be used for the preparation of large and complex absorbing structures, and has good application prospects. The C-shaped composite absorbing structure prepared by the preparation method of the present invention has both structural strength and absorbing performance on the basis of ensuring a small deformation, and can meet the use requirements of low-scattering target rotating body components.

[0041] In some specific embodiments of the present invention, in step S1, design and simulation are performed according to the thickness, weight, electrical properties and mechanical properties of the C-shaped component. After the simulation, the actual flat plate laying is verified and the final laying plan is determined through multiple rounds of iterations.

[0042] The preparation method provided by the present invention is simple and feasible, highly efficient, low-cost, and universal, and does not require complex and repeated multiple rounds of mold repair and inversion after extracting basic parameters of several types of materials as in the past to solve the deformation problem. The deformation during the molding process is small, and the molding tooling and the film adhesion inspection tooling can be shared, which can achieve improved economic benefits.

[0043] In some specific embodiments of the present invention, the demoulding material is selected from at least one of a demoulding cloth, a demoulding film, and a demoulding agent. The above demoulding materials are only used to illustrate the technical solution of the present invention and are not limiting. The demoulding material can be selected as long as it can meet the demoulding requirements and is easy to remove.

[0044] According to some preferred embodiments, the method for preparing the microwave absorbing prepreg comprises: distributing the microwave absorbing slurry on the surface of the substrate, and drying to obtain the microwave absorbing prepreg;

[0045] The microwave absorbing slurry comprises an absorbent, a resin, an auxiliary agent and a solvent.

[0046] In some specific embodiments of the present invention, the method for preparing the microwave absorbing prepreg comprises: coating the microwave absorbing slurry on a release paper, and drying the solvent to obtain a semi-cured microwave absorbing prepreg.

[0047] According to some preferred embodiments, the absorbent is a magnetic absorbent, preferably one or more of carbonyl iron powder, ferrite, and sendust;

[0048] According to some preferred embodiments, the resin is an epoxy resin, preferably a medium-temperature epoxy resin;

[0049] According to some preferred embodiments, the auxiliary agent includes at least one of glass microspheres and a co-solvent, preferably, the co-solvent is at least one of xylene and n-butanol; and / or

[0050] According to some preferred embodiments, the solvent is ethyl acetate.

[0051] The types of absorbents, resins, additives and solvents listed above in the present invention are only for illustrating the technical solutions of the present invention and are not limiting. The types of absorbents, resins, additives and solvents can be selected according to the performance requirements of the actual application scenarios.

[0052] According to some preferred embodiments, the wave-transmitting prepreg is a low dielectric prepreg, preferably one or more of quartz fiber cloth / epoxy resin prepreg, glass fiber cloth / epoxy resin prepreg, and aramid fiber cloth / epoxy resin prepreg.

[0053] According to some preferred embodiments, the raw materials for preparing the pressure balancing plate include glass fiber prepreg and Airpad rubber.

[0054] According to some preferred embodiments, the preparation method of the pressure equalizing plate comprises: laying glass fiber prepreg and Airpad rubber on the surface of the substrate in sequence, and obtaining the pressure equalizing plate through a second curing molding; the size of the substrate is consistent with the size of the C-shaped composite wave absorbing structure; preferably, the second curing molding adopts an autoclave molding process. The pressure equalizing plate of the present invention comprises a glass fiber layer and an Airpad rubber layer, wherein the glass fiber layer provides the strength required for the pressure equalizing plate, and the Airpad rubber layer has a certain deformation ability and can play a role in pressure equalization.

[0055] According to some preferred embodiments, step S4 includes: sequentially bonding the carbon fiber layer, the wave absorbing layer and the wave transparent layer with an adhesive film, and then performing a third curing process to obtain a C-shaped composite wave absorbing structure.

[0056] According to some preferred embodiments, the resin system used in the adhesive film is the same as the resin system used in the carbon fiber prepreg, the microwave absorbing prepreg and the microwave transmitting prepreg.

[0057] According to some preferred embodiments, the first curing molding adopts an autoclave molding process.

[0058] According to some preferred embodiments, the third curing molding adopts an autoclave molding process.

[0059] The present invention provides a C-shaped composite wave absorbing structure in a second aspect, which is prepared by the preparation method described in the first aspect.

[0060] In order to more clearly illustrate the technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the examples. The present invention does not specifically limit the sources of the reagents used in the examples and comparative examples, and the reagents can be directly purchased or synthesized by themselves.

[0061] Example 1

[0062] A C-shaped composite wave absorbing structure comprises a carbon fiber layer 11, a wave absorbing layer 12 and a wave transparent layer 13 which are sequentially composited from the inside to the outside, and has a thickness of 4.2 mm. The preparation method of the C-shaped composite wave absorbing structure comprises the following steps:

[0063] Preparation of microwave absorbing prepreg:

[0064] 3000g of flaky carbonyl iron powder, 2000g of medium-temperature epoxy resin, 500g of ethyl acetate, 100g of glass microspheres, 50g of xylene, and 50g of n-butanol were fully mixed, and mechanically stirred at a speed of 1000r / min for 30 minutes to obtain 1# absorbing slurry. The absorbing slurry was scraped onto release paper with a single sheet thickness of 0.2mm, and dried in a drying oven at 50°C for 1h to obtain semi-cured 1# absorbing prepreg;

[0065] 3000g of spherical carbonyl iron powder, 2000g of medium-temperature epoxy resin, 500g of ethyl acetate, 100g of glass microspheres, 50g of xylene, and 50g of n-butanol were fully mixed, and mechanically stirred at a speed of 1000r / min for 30 minutes to obtain 2# absorbing slurry. The absorbing slurry was scraped onto release paper with a single sheet thickness of 0.2mm, and dried in a drying oven at 50°C for 1h to obtain semi-cured 2# absorbing prepreg;

[0066] 1000g of spherical carbonyl iron powder, 2000g of medium-temperature epoxy resin, 500g of ethyl acetate, 100g of glass microspheres, 50g of xylene, and 50g of n-butanol were fully mixed and mechanically stirred at a speed of 1000r / min for 30 minutes to obtain 3# absorbing slurry. The absorbing slurry was scraped onto release paper with a single sheet thickness of 0.2mm, and dried at 50°C in a drying oven for 1h to obtain semi-cured 3# absorbing prepreg.

[0067] Design of thickness of each layer: According to the performance requirements, the thickness of each layer of the C-shaped structure with a thickness of 4.2mm is designed, the thickness of the carbon fiber layer is 0.8mm, the thickness of the absorbing layer is 2.2mm, and the thickness of the transparent layer is 1.2mm; the absorbing layer uses the above three types of absorbing prepregs, from the carbon fiber layer to the transparent layer, the carbon fiber layer is 4 carbon fiber prepregs (select JH / 2160 / CW200T), and the thickness of a single sheet is 0.2mm; the absorbing layer is arranged with 6 1# absorbing prepregs (total thickness 1.2mm), 3 2# absorbing prepregs (total thickness 0.6mm), and 2 3# absorbing prepregs (total thickness 0.4mm); the transparent layer is 10 glass fiber prepregs (select Guangwei S15000), and the thickness of a single sheet is 0.12mm.

[0068] Laying: Cut the prepreg according to the width of the C-shaped composite absorbing structure. Use an automatic feeding machine to cut the three types of prepregs. Mark the layer number of each prepreg for easy laying. Clean and wipe the mold tooling, clarify the laying area, use projection equipment to assist in laying, first lay a layer of release cloth in the laying area on the tooling, and use a scraper to assist in laying the 4 carbon fiber prepregs in the laying area in turn. After laying, the surface is flat and smooth without wrinkles, overlaps, scratches, depressions, protrusions, cracks, sand holes and other defects. After laying, lay the release cloth on the outermost layer; then use a scraper to assist in laying 6 1# absorbing prepregs, 3 2# absorbing prepregs, and 2 3# absorbing prepregs. The tools are laid in sequence to the paving area. After the paving is completed, the surface is flat and smooth without wrinkles, overlaps, scratches, depressions, protrusions, cracks, sand holes and other defects. After the paving is completed, the release cloth is laid on the outermost layer; then 10 sheets of glass fiber prepreg are laid in sequence to the paving area using a scraper auxiliary tool. After the paving is completed, the surface is flat and smooth without wrinkles, overlaps, scratches, depressions, protrusions, cracks, sand holes and other defects. After the paving is completed, the release cloth is laid on the outermost layer; in order to ensure the surface quality, the glass fiber prepreg A pressure equalizing plate is laid on the outside of the outermost layer of demoulding cloth to increase the compactness and airtightness of the molding process; the preparation method of the pressure equalizing plate includes: cutting 21 sheets of carbon fiber prepreg (single sheet thickness is 0.2mm), laying demoulding cloth on the surface of the tooling, laying 21 sheets of carbon fiber prepreg in turn to the laying area, bagging and vacuuming into the autoclave for the molding process, heating to 130℃ at a heating rate of 5℃ / min and keeping warm for 2h, the pressure of the molding process is 6bar, and after the furnace cools to room temperature, the pressure is released and the can is opened to take out the parts , and obtain a carbon fiber fake part with the same thickness as the real C-shaped composite absorbing structure; use the fake part as the positive mold, lay the demoulding cloth, lay 2 glass fiber prepregs (single sheet thickness is 0.12mm) and 3mm thick Airpad rubber on its surface, bag it and evacuate it into the autoclave for the molding process, heat it to 130℃ at a heating rate of 5℃ / min and keep it warm for 2h. The pressure of the molding process is 6bar. After the furnace cools to room temperature, the pressure is released and the can is opened to take out the parts to obtain the equalizing plate.

[0069] Curing and molding: Pavement strips are laid around the ply area to control the curing and molding position of the C-shaped composite absorbing structure. Bags are made on the outside of the equalizing plate and vacuumed. The structure is placed in an autoclave for curing and molding according to the prepreg curing conditions. The temperature is raised to 130°C at a heating rate of 5°C / min and kept warm for 2 hours. The pressure during the molding process is 6 bar. After the pressure is released and the tank is opened after the furnace cools to room temperature, the release cloth between the layers is torn off. After cleaning the surrounding glue overflow and surface defects, the C-shaped carbon fiber layer, absorbing layer and wave-transmitting layer are obtained respectively.

[0070] Composite: Place the carbon fiber layer back in the tooling laying area, lay epoxy resin film on the outside of the carbon fiber layer, press the absorbing layer on the film, and then lay epoxy resin film on the surface of the absorbing layer, press the wave-transmitting layer on the film, bag the surface and put it into the tank again, and cure it according to the prepreg curing conditions. Heat the temperature to 130℃ at a rate of 5℃ / min and keep it warm for 2h. The pressure during the molding process is 6bar. After drying to room temperature, take it out of the tank to obtain a C-shaped composite absorbing structure, such as Figure 2 shown.

[0071] The C-shaped composite absorbing structure prepared in this embodiment is placed back into the layering area of ​​the molding tooling, and pressed with a finger or a weight at (110-147) N. When pressing, the span between the fixed point and the pressing point is ≥200 mm, and the maximum gap is 0.4 mm. Figure 3 shown.

[0072] Comparative Example 1

[0073] A C-shaped composite wave absorbing structure includes a carbon fiber layer 11, a wave absorbing layer 12 and a wave transparent layer 13 integrally formed from the inside to the outside, with a thickness of 4.2 mm; the preparation method of the C-shaped composite wave absorbing structure is basically the same as that of Example 1, except that: in the layer laying process, after the 4 carbon fiber prepregs are laid, the release cloth is not laid on the outermost layer; after the 6 1# wave absorbing prepregs, 3 2# wave absorbing prepregs, and 2 3# wave absorbing prepregs are laid, the release cloth is not laid on the outermost layer. After curing and molding, a C-shaped composite wave absorbing structure integrally formed with a carbon fiber layer, a wave absorbing layer and a wave transparent layer is obtained.

[0074] The C-shaped composite absorbing structure prepared in this comparative example is placed back into the layering area of ​​the molding tooling, and pressed with a finger or weight at (110-147) N. When pressing, the span between the fixed point and the pressing point is ≥200 mm, and the maximum gap is 7.5 mm. Figure 4 shown.

[0075] Comparative Example 2

[0076] A C-shaped composite absorbing structure includes a carbon fiber layer 11, an absorbing layer 12 and a transparent layer 13 which are laminated in sequence from the inside to the outside, and has a thickness of 4.2 mm. The preparation method of the C-shaped composite absorbing structure is basically the same as that of Example 1, except that: during the lamination process, an equalizing plate is not laid on the outside of the outermost release cloth of the glass fiber prepreg.

[0077] The C-shaped composite absorbing structure prepared in this comparative example is put back into the laying area of ​​the molding tooling, and is pressed with a finger or a weight at (110-147) N. When pressed, the span between the fixed point and the pressing point is ≥200 mm, the maximum gap is measured to be 0.4 mm, and the deformation does not change significantly. However, the outer surface of the C-shaped composite absorbing structure is rough and the thickness is uneven.

[0078] In summary, compared with the traditional preparation method of C-shaped composite absorbing structure, the preparation method of the C-shaped composite absorbing structure provided by the present invention has controllable deformation and high molding accuracy, and can be used for the preparation of large and complex absorbing structures. On the basis of ensuring a small deformation, it has both structural strength and absorbing performance, and has good application prospects.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. 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 method for preparing a C-shaped composite absorbing structure, characterized in that: The preparation method comprises: S1. According to the performance requirements of the C-shaped composite absorbing structure, the carbon fiber prepreg, the absorbing prepreg and the transparent prepreg are layered to obtain a layered prepreg; the layered prepreg includes the carbon fiber prepreg, the absorbing prepreg and the transparent prepreg from the inside to the outside; a release material is laid between the carbon fiber prepreg and the absorbing prepreg and between the absorbing prepreg and the transparent prepreg; S2. Laying a pressure plate on the outside of the prepreg after the layering, and then performing a first curing molding, removing the release material, to obtain a carbon fiber layer, an absorbing layer and a wave-transmitting layer; a release material is laid between the prepreg after the layering and the pressure plate; S3. Compounding the carbon fiber layer, the wave absorbing layer and the wave transparent layer in sequence to obtain a C-shaped composite wave absorbing structure.

2. The preparation method according to claim 1, characterized in that: The preparation method of the absorbing prepreg comprises: distributing the absorbing slurry on the surface of the substrate, and drying to obtain the absorbing prepreg; the absorbing slurry comprises an absorbent, a resin, an auxiliary agent and a solvent.

3. The preparation method according to claim 2, characterized in that: The absorbent is a magnetic absorbent, preferably one or more of carbonyl iron powder, ferrite, and sendust; The resin is an epoxy resin, preferably a medium-temperature epoxy resin; The auxiliary agent includes at least one of glass microspheres and a co-solvent, preferably, the co-solvent is at least one of xylene and n-butanol; and / or The solvent is ethyl acetate.

4. The preparation method according to claim 1, characterized in that: The wave-transmitting prepreg is a low-dielectric prepreg, preferably one or more of quartz fiber cloth / epoxy resin prepreg, glass fiber cloth / epoxy resin prepreg, and aramid fiber cloth / epoxy resin prepreg.

5. The preparation method according to claim 1, characterized in that: The raw materials for preparing the pressure balancing plate include glass fiber prepreg and Airpad rubber.

6. The preparation method according to claim 5, characterized in that: The preparation method of the pressure equalizing plate comprises: laying glass fiber prepreg and Airpad rubber on the surface of a substrate in sequence, and obtaining the pressure equalizing plate through a second curing molding; the size of the substrate is consistent with the size of the C-shaped composite absorbing structure; preferably, the second curing molding adopts an autoclave molding process.

7. The preparation method according to claim 1, characterized in that: Step S4 includes: using an adhesive film to sequentially bond the carbon fiber layer, the wave absorbing layer and the wave transparent layer, and then performing a third curing process to obtain a C-shaped composite wave absorbing structure.

8. The preparation method according to claim 7, characterized in that: The resin system used in the adhesive film is the same as the resin system used in the carbon fiber prepreg, the wave absorbing prepreg and the wave transmitting prepreg.

9. The preparation method according to claim 7, characterized in that: The first curing molding adopts a hot-pressing molding process; and / or The third curing molding adopts a hot-pressing molding process.

10. A C-shaped composite absorbing structure, characterized in that: The method is prepared by the preparation method according to any one of claims 1 to 9.

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