A method for forming a special-shaped heat-proof layer

Abstract

The present application discloses a method for forming a special-shaped heat-proof layer, belonging to the technical field of composite material forming. The molding method includes: preparing a first prepreg and cutting the first prepreg at a first angle to obtain an inner layer prepreg block, and cutting the first prepreg at a second angle to obtain an outer layer prepreg block; laying the inner layer prepreg block layer by layer on the load-bearing body in a warp and weft staggered manner, and laying the outer layer prepreg block layer by layer on the inner layer prepreg block in a warp and weft staggered manner to obtain a large-area heat protection layer laying layer group; preparing an edge heat protection layer embryo; cutting off the thin-walled area on the edge heat protection layer embryo; placing the edge heat protection layer embryo after cutting off the thin-walled area on a molding tool, and laying a second prepreg in the area of ​​the molding tool corresponding to the cut-off part and pre-pressing it to obtain an edge heat protection layer composite embryo; burying the edge heat protection layer composite embryo in the prepreg laying layer group to obtain a special-shaped structure heat protection layer embryo; curing the special-shaped structure heat protection layer embryo to obtain a special-shaped structure heat protection layer.

Description

Technical Field

[0001] The present application belongs to the technical field of composite material forming, and in particular relates to a method for forming a special-shaped heat-resistant layer. Background Art

[0002] Most traditional aircraft have regular cylindrical or conical structures. In order to meet aerodynamic requirements, high-speed aircraft are designed with special-shaped structures to maintain a high lift-to-drag ratio. Since their flight environment needs to pass through thin gas layers and dense atmosphere, aerodynamic heating is extremely harsh. In order to better control accuracy and flight distance, their thermal protection structure is required to be resistant to high temperatures, lightweight, ablation-resistant, and high-strength.

[0003] Compared with traditional aircraft structures, the surface of special-shaped aircraft is more complex, and the heat protection layer is very easy to deform after forming. During the combination process with the load-bearing shell, it brings problems such as difficulty in dimensional control and inaccurate positioning. Summary of the Invention

[0004] The present application aims to at least to some extent solve the technical problem of large deformation of a special-shaped heat-proof layer after forming. To this end, the present application provides a method for forming a special-shaped heat-proof layer.

[0005] The present invention provides a method for forming a heat-resistant layer having a special-shaped structure, comprising:

[0006] Preparing a first prepreg and cutting the first prepreg at a first angle to obtain an inner layer prepreg block, and cutting the first prepreg at a second angle to obtain an outer layer prepreg block;

[0007] The inner layer prepreg blocks are laid layer by layer on the load-bearing body in a warp-and-weft staggered manner, and the outer layer prepreg blocks are laid layer by layer on the inner layer prepreg blocks in a warp-and-weft staggered manner to obtain a large-area heat-proof layer laying layer group;

[0008] Prepare the embryo of the edge heat protection layer;

[0009] Cutting off the thin wall area on the edge heat protection layer embryo;

[0010] Placing the edge heat protection layer embryo after the thin-walled area is cut off on a molding tool, and laying a second prepreg in the area of ​​the molding tool corresponding to the cut-off portion and pre-pressing it to obtain an edge heat protection layer composite embryo;

[0011] embedding the edge heat protection layer composite embryo into the prepreg layup layer group to obtain a special-shaped heat protection layer embryo;

[0012] The embryonic body of the special-shaped heat-proof layer is cured to obtain the special-shaped heat-proof layer.

[0013] In some embodiments, the curing process is performed by step temperature, and when the curing temperature is 80° C. to 100° C., the temperature is kept for 6 h to 8 h; when the curing temperature is 110° C. to 130° C., the temperature is kept for 3 h to 4 h.

[0014] In some embodiments, the thickness of the first prepreg is 0.5 mm to 2.5 mm, the first prepreg is a 2.5D woven fabric prepreg, the fibers of the first prepreg are a blended fabric of quartz fibers and organic fibers, and the resin of the first prepreg is phenolic resin.

[0015] In some embodiments, the thickness of the second prepreg is 0.5 mm to 1 mm, the second prepreg is a 2.5D woven fabric prepreg, the fibers of the second prepreg are a blended fabric of quartz fibers and organic fibers, and the resin of the second prepreg is phenolic resin.

[0016] In some embodiments, the edge heat protection layer embryo is prepared by a molding process.

[0017] In some embodiments, the prepreg material of the edge heat protection layer embryo includes mixed fibers, aerosol fillers and resins, wherein the mixed fibers include two or three of quartz fibers, carbon fibers or high silica fibers, the aerosol fillers are one or two of hollow microbeads or boron carbide, and the resin includes one or more of barium phenolic formaldehyde, aminophenolic formaldehyde or modified phenolic formaldehyde.

[0018] In some embodiments, the first angle is 45° and the second angle is 90°.

[0019] In some embodiments, each layer of the large-area heat-protection layer laying layer group is formed by splicing 4 to 6 pieces of the inner layer prepreg blocks, or is formed by splicing 2 to 3 pieces of the outer layer prepreg blocks.

[0020] In some embodiments, the splicing positions of two adjacent inner prepreg blocks in the same layer are connected by quartz sutures, and the splicing positions of two adjacent outer prepreg blocks in the same layer are also connected by quartz sutures.

[0021] In some embodiments, the thin-walled region is a region with a thickness less than 5 mm.

[0022] The present invention has at least the following beneficial effects:

[0023] The present invention provides a method for forming a heat-resistant layer with a special structure. The inner and outer prepreg blocks are laid in a warp-weft staggered pattern, allowing the first prepreg to maintain the same warp and weft orientation during the layup process, reducing differences in various anisotropic properties. The inner and outer prepreg blocks are cut at different angles, ensuring their conformability and ductility during layup, allowing the first prepreg to better conform to the outer surface of the load-bearing structure. The present invention first prepares an edge heat protection layer embryo, then cuts off the thin-walled area of ​​the edge heat protection layer embryo, and then fills the cut-off area by laying and pre-pressing a second prepreg to obtain an edge heat protection layer composite embryo, and then buries the edge heat protection layer composite embryo in a prepreg laying layer group to obtain a heat protection layer embryo, and then cures the heat protection layer embryo to obtain a special-shaped heat protection layer. The present invention cuts off the thin-walled area and uses a second prepreg conformal transition filling layer to form a thin-walled area, so that the thin-walled area and the large-area heat protection layer area of ​​the first prepreg layer are co-cured and formed, reducing the deformation of the thin-walled area. Compared with the special-shaped heat protection layer processed by the existing technology, the special-shaped heat protection layer prepared according to the special-shaped heat protection layer forming method of the present invention can reduce the deformation of the special-shaped heat protection layer by more than 60%. The special-shaped heat protection layer forming method of the present invention can effectively reduce the deformation of the special-shaped heat protection layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 A schematic cross-sectional view of the first and second ends of the special-shaped heat protection layer in one or more embodiments of the present application is shown.

[0026] Figure 2 A schematic structural diagram of a special-shaped heat-resistant layer in one or more embodiments of the present application is shown.

[0027] Figure 3 A flow chart of a method for forming a special-shaped heat-resistant layer in one or more embodiments of the present application is shown.

[0028] Figure 4 A schematic diagram of cutting an inner layer prepreg block in one or more embodiments of the present application is shown.

[0029] Figure 5 A schematic diagram of cutting an outer layer prepreg block in one or more embodiments of the present application is shown.

[0030] Figure 6A schematic diagram is shown of cutting off the thin-walled area on the edge heat protection layer embryo body and then laying the second prepreg and pre-pressing it in one or more embodiments of the present application.

[0031] Reference numerals: 1 - first end, 2 - second end, 1.1 - upper portion, 1.2 - lower portion, 1.21 - first straight edge, 1.22 - second straight edge, 1.23 - curved edge. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship and movement status of various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0034] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] In addition, in the present invention, descriptions such as "first" and "second" are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] Most traditional aircraft have regular cylindrical or conical structures. In order to meet aerodynamic requirements, high-speed aircraft are designed with special-shaped structures to maintain a high lift-to-drag ratio. Since their flight environment needs to pass through thin gas layers and dense atmosphere, aerodynamic heating is extremely harsh. In order to better control accuracy and flight distance, their thermal protection structure is required to be resistant to high temperatures, lightweight, ablation-resistant, and high-strength.

[0037] Compared with traditional aircraft structures, the surface of special-shaped aircraft is more complex. In addition, due to the anisotropic characteristics of composite materials, combined with thin walls, multiple interfaces and other structures, the heat-proof layer is very easy to deform after forming. In the process of combining with the load-bearing shell, it brings problems such as difficulty in dimensional control and inaccurate positioning. At the same time, large internal stress is formed between the heat-proof layer and the load-bearing shell, which poses a great risk to the stability of the structure during the use of the aircraft.

[0038] In the related art, special-shaped heat-proof layers have the technical problem of large deformation after forming. The present application provides a method for forming a special-shaped heat-proof layer, which can at least to some extent solve the technical problem of large deformation after forming a special-shaped heat-proof layer.

[0039] In some embodiments of the present application, the following special-shaped heat-proof layers are formed by the special-shaped heat-proof layer forming method:

[0040] like Figure 1 and Figure 2 As shown, the special-shaped heat shield comprises a first end 1 and a second end 2, which are connected by a tapered surface. The second end 2 of the special-shaped heat shield has a circular cross-section. The upper portion 1.1 of the first end 1 has an I-shaped cross-section. The lower portion 1.2 of the first end 1 has a cross-section that includes a first straight edge 1.21, a second straight edge 1.22, and a curved edge 1.23. One end of the first straight edge 1.21 and one end of the second straight edge 1.22 connect to the two ends of the I-shape, respectively. Both the first straight edge 1.21 and the second straight edge 1.22 are parallel to the centerline of the I-shape. The other ends of the first straight edge 1.21 and the other ends of the second straight edge 1.22 are connected by a curved edge 1.23. The curved edge 1.23 is arc-shaped and is positioned away from the center of the I-shape.

[0041] like Figure 2 As shown, the special-shaped heat protection layer consists of two edge heat protection layers ( Figure 2 The heat shield is composed of a large-area heat shield (the area with the middle dashed line) and a large-area heat shield (all areas except the edge heat shield are large-area heat shield). The thickness of the large-area heat shield is relatively uniform, while the edge heat shield is located closer to the first end. The edge heat shield has an uneven thickness, thicker at one end and thinner at the other. The maximum thickness of the edge heat shield ranges from 40mm to 60mm, and the minimum thickness is only 0.5mm. This special-shaped heat shield has small acute angles, rounded corners, and beveled surfaces.

[0042] This special-shaped heat shield has a thin, irregularly shaped structure, resulting in poor rigidity. Furthermore, the thickness of the special-shaped heat shield varies from place to place, resulting in inconsistent rigidity across multiple interfaces. Consequently, existing methods can result in significant deformation after forming the heat shield. Furthermore, due to the large size of the heat shield, the heat shield's profile changes in a complex manner, making deformation control difficult with a single method. Experiments have shown that, compared to conventional methods for forming the heat shield, the heat shield produced using the present invention's heat shield forming method can reduce deformation by over 60%. This method significantly reduces deformation in heat shields.

[0043] It should be noted that the method for forming a special-shaped heat-proof layer provided by the present invention can be used to form the above-mentioned special-shaped heat-proof layer. Of course, it can also be used to form other special-shaped heat-proof layers, such as the special-shaped heat-proof layer disclosed in Patent Publication No. CN116372506A. Figure 1 The disclosed special-shaped structure may also be the one disclosed in Patent Publication No. CN111196048B. Figure 2 The disclosed special-shaped structures are not limited in this application.

[0044] The following is a detailed description of the method for forming the special-shaped heat-resistant layer of the present application:

[0045] like Figure 3 As shown, the method for forming a special-shaped structure heat-proof layer includes steps S100, S200, S300, S400, S500, S600 and S700.

[0046] S100, such as Figure 4 and Figure 5 As shown, a first prepreg is prepared and cut according to a first angle to obtain an inner layer prepreg block, and the first prepreg is cut according to a second angle to obtain an outer layer prepreg block.

[0047] The purpose of this step is to cut the first prepreg into multiple inner prepreg blocks for laying out the inner layer of the special-shaped heat-proof layer, and cut it into multiple outer prepreg blocks for laying out the outer layer of the special-shaped heat-proof layer. Figure 4 and Figure 5 As shown, the first angle is 45° and the second angle is 90°.

[0048] The first prepreg has a thickness of 0.5 mm to 2.5 mm and is a 2.5D woven fabric prepreg. The fibers of the first prepreg are a blend of quartz fiber and organic fiber, and the resin of the first prepreg is phenolic resin. The organic fiber can be phenolic fiber, nylon fiber, or aromatic sulfone fiber. The quartz fiber can be type B, type C, or type D.

[0049] S200, laying the inner prepreg blocks layer by layer on the load-bearing body in a warp-and-weft staggered manner, and laying the outer prepreg blocks layer by layer on the inner prepreg blocks in a warp-and-weft staggered manner to obtain a large-area heat-proof layer laying layer group.

[0050] Specifically, the inner prepreg blocks are laid out first, followed by the outer prepreg blocks. The inner prepreg blocks are laid out layer by layer, alternating warp and weft. Similarly, the outer prepreg blocks are laid out layer by layer, similarly alternating warp and weft. In other words, both the inner and outer prepreg blocks are laid out in the order of 0°, 90°, 0°, 90°, and so on, to minimize differences in anisotropy.

[0051] It should be noted that the inner layer prepreg blocks and the outer layer prepreg blocks are first laid and then cured to form a large-area heat protection layer. Therefore, when laying the inner layer prepreg blocks and the outer layer prepreg blocks, they are only laid in the area corresponding to the position of the large-area heat protection layer on the load-bearing body.

[0052] Considering that the load-bearing body of the special-shaped heat-proof layer will expand and contract due to the influence of high and low temperatures during the curing process, and the deformation of different areas of the special-shaped surface is inconsistent, it is not advisable to use a whole sheet of prepreg cloth to lay the load-bearing body during the laying process. Therefore, each layer of the large-area heat-proof layer laying layer group is formed by splicing 4 to 6 inner layer prepreg blocks, or by splicing 2 to 3 outer layer prepreg blocks. Specifically, each inner layer of the special-shaped heat-proof layer is formed by splicing 4 to 6 inner layer prepreg blocks, and each outer layer of the special-shaped heat-proof layer is formed by splicing 2 to 3 outer layer prepreg blocks. This improves the deformation capacity of the inner layer of the special-shaped heat-proof layer and improves the integrity of the outer layer of the special-shaped heat-proof layer. The splicing positions of two adjacent inner layer prepreg blocks in the same layer are connected by quartz stitching, and the splicing positions of two adjacent outer layer prepreg blocks in the same layer are also connected by quartz stitching to reduce the internal stress of the special-shaped heat-proof layer blank during the curing process.

[0053] For ease of understanding, an example is given below: if the large-area heat-proof layer laying group has a total of six layers, from the inside to the outside the first, second and third layers are inner layers, and the fourth, fifth and sixth layers are outer layers, then the first, second and third layers are all formed by 4 to 6 inner layer prepreg blocks spliced ​​together by grouting, and the fourth, fifth and sixth layers are all formed by 2 to 3 outer layer prepreg blocks spliced ​​together by grouting.

[0054] S300, preparing the embryonic body of the edge heat protection layer.

[0055] The maximum thickness of the edge heat shield is 40mm to 60mm, with a minimum thickness of only 0.5mm. Its structure features small acute angles, rounded corners, and beveled surfaces. To ensure the appearance quality, the edge heat shield blank is produced through a molding process. During the molding process, the prepreg material of the edge heat shield blank includes mixed fibers, aerosol fillers, and resin. The mixed fibers include two or three of quartz fibers, carbon fibers, or high-silica fibers. The aerosol fillers are one or two of hollow microspheres or boron carbide. The resin includes one or more of barium phenolic formaldehyde, aminophenolic formaldehyde, or modified phenolic formaldehyde.

[0056] Specifically, the prepreg of the edge heat protection layer embryonic body is added into a mold with the same shape and size as the edge heat protection layer, and then the mold is closed for pre-pressing and demolding to obtain the edge heat protection layer embryonic body.

[0057] S400, such as Figure 6 As shown, the thin wall area of ​​the marginal heat shield embryo was removed.

[0058] After the edge heat protection layer embryo is prepared through the molding process, the area with a thickness of less than 5mm is a thin-walled area. The rigidity of this area is weak and the deformation is large. If it is not cut off, it will affect the overall deformation of the special-shaped structure heat protection layer. Therefore, this step cuts off the thin-walled area with a thickness of less than 5mm on the edge heat protection layer embryo.

[0059] S500, such as Figure 6 As shown, the edge heat protection layer embryo body after the thin-wall area is cut off is placed on a molding tool, and a second prepreg is laid and pre-pressed in the area of ​​the molding tool corresponding to the cut-off part to obtain an edge heat protection layer composite embryo body.

[0060] In step S400, the thin-walled area of ​​the edge heat shielding layer embryonic body is removed. Step S500 is to form the removed thin-walled area by laying a second prepreg and pre-pressing it. Therefore, the second prepreg is laid and pre-pressed in the area of ​​the molding tooling corresponding to the removed area. It should be noted that at least a portion of the second prepreg is laid on the edge heat shielding layer embryonic body after the thin-walled area has been removed, so that the thin-walled area formed by the second prepreg after pre-pressing is fixedly connected to the edge heat shielding layer embryonic body after the thin-walled area has been removed.

[0061] The second prepreg has a thickness of 0.5mm to 1mm and is a 2.5D woven fabric prepreg. The fibers of the second prepreg are a blend of quartz fiber and organic fiber, and the resin of the second prepreg is phenolic resin. The organic fiber can be phenolic fiber, nylon fiber, or aromatic sulfone fiber, and the quartz fiber can be type B, C, or D. Using a 3D model, several thin-walled sections can be cut. The thickness and number of layers of the second prepreg can be designed based on these sections. The prepreg is then laid layer by layer until it matches the shape of the thin-walled area of ​​the edge heat shield. The prepreg is then pre-pressed through mold closing to ensure the shape is close to the net size.

[0062] S600: embedding the composite embryonic body of the edge heat protection layer into the prepreg laying layer group to obtain the embryonic body of the heat protection layer.

[0063] The edge of the edge heat protection layer composite embryo is placed between two adjacent prepreg laying layers, so that after curing, the edge heat protection layer composite embryo is fixedly connected to the large area heat protection layer laying layer group.

[0064] S700: Curing the heat protection layer embryo to obtain a heat protection layer with a special structure.

[0065] After curing, the special-shaped heat-resistant layer is fixed to the load-bearing structure. The curing process is carried out through a step-by-step temperature process, with a heat preservation time of 6 to 8 hours at a curing temperature of 80 to 100 degrees Celsius, and a heat preservation time of 3 to 4 hours at a curing temperature of 110 to 130 degrees Celsius.

[0066] In some embodiments, when performing a step-temperature curing process, the temperature of the secondary pre-compacted heat shield layer embryo assembly is gradually raised from room temperature to 80°C to 100°C. After reaching 80°C to 100°C, it is maintained at this temperature for 6 to 8 hours. After maintaining this temperature for 6 to 8 hours, the temperature is gradually raised to 110°C to 130°C. After reaching 110°C to 130°C, it is maintained at this temperature for 3 to 4 hours. After maintaining this temperature for 3 to 4 hours, the temperature is raised to the set maximum curing temperature. Once the temperature reaches the maximum curing temperature, the temperature is lowered, allowing the secondary pre-compacted heat shield layer embryo assembly to gradually cool to room temperature. In some embodiments, the maximum curing temperature is 180°C.

[0067] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0068] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0069] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for forming a special-shaped heat-proof layer, characterized in that: include: Preparing a first prepreg and cutting the first prepreg at a first angle to obtain an inner layer prepreg block, and cutting the first prepreg at a second angle to obtain an outer layer prepreg block; The inner layer prepreg blocks are laid layer by layer on the load-bearing body in a warp-and-weft staggered manner, and the outer layer prepreg blocks are laid layer by layer on the inner layer prepreg blocks in a warp-and-weft staggered manner to obtain a large-area heat-proof layer laying layer group; Prepare the embryo of the edge heat protection layer; Cutting off the thin wall area on the edge heat protection layer embryo; Placing the edge heat protection layer embryo after the thin-walled area is cut off on a molding tool, and laying a second prepreg in the area of ​​the molding tool corresponding to the cut-off portion and pre-pressing it to obtain an edge heat protection layer composite embryo; embedding the edge heat protection layer composite embryo into the prepreg layup layer group to obtain a special-shaped heat protection layer embryo; The embryonic body of the special-shaped heat-proof layer is cured to obtain the special-shaped heat-proof layer.

2. The method for forming a special-shaped heat-proof layer according to claim 1, characterized in that: The curing treatment is carried out by step temperature. When the curing temperature is 80° C. to 100° C., the temperature is kept for 6 hours to 8 hours. When the curing temperature is 110° C. to 130° C., the temperature is kept for 3 hours to 4 hours.

3. The method for forming a special-shaped heat-proof layer according to claim 1, characterized in that: The thickness of the first prepreg is 0.5 mm to 2.5 mm. The first prepreg is a 2.5D woven fabric prepreg. The fibers of the first prepreg are a mixed fabric of quartz fibers and organic fibers. The resin of the first prepreg is phenolic resin.

4. The method for forming a special-shaped heat-proof layer according to claim 1, characterized in that: The thickness of the second prepreg is 0.5 mm to 1 mm. The second prepreg is a 2.5D woven fabric prepreg. The fibers of the second prepreg are a mixed fabric of quartz fibers and organic fibers. The resin of the second prepreg is phenolic resin.

5. The method for forming a special-shaped heat-proof layer according to claim 1, characterized in that: The edge heat protection layer embryo is prepared by a molding process.

6. The method for forming a special-shaped heat-proof layer according to claim 5, characterized in that: The prepreg material of the edge heat protection layer embryo body includes mixed fibers, air-energy fillers and resins, wherein the mixed fibers include two or three of quartz fibers, carbon fibers or high-silica fibers, the air-energy fillers are one or two of hollow microbeads or boron carbide, and the resin includes one or more of barium phenolic formaldehyde, aminophenolic formaldehyde or modified phenolic formaldehyde.

7. The method for forming a special-shaped heat-proof layer according to any one of claims 1 to 6, characterized in that: The first angle is 45°, and the second angle is 90°.

8. The method for forming a special-shaped heat-proof layer according to any one of claims 1 to 6, characterized in that: Each layer of the large-area heat-proof layer laying layer group is formed by splicing 4 to 6 inner layer prepreg blocks, or is formed by splicing 2 to 3 outer layer prepreg blocks.

9. The method for forming a special-shaped heat-proof layer according to claim 8, characterized in that: The splicing positions of two adjacent inner layer prepreg blocks in the same layer are connected by quartz stitching lines, and the splicing positions of two adjacent outer layer prepreg blocks in the same layer are also connected by quartz stitching lines.

10. The method for forming a special-shaped heat-proof layer according to any one of claims 1 to 6, characterized in that: The thin-walled area is an area with a thickness of less than 5 mm.

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