Spherical ultra-thin carbon-carbon screen blank and layering compression molding structure

Abstract

The invention discloses a spherical ultra-thin carbon-carbon screen blank and a layering compression molding structure, and belongs to the technical field of engine design. The layering compression molding structure comprises a male die and a female die. A first inclined plane on the surface of one side of a male die and a second inclined plane on the concave surface of a female die are designed to have a certain inclined angle, and the radius value of a spherical boss of the male die is designed to be slightly larger than the radius value of the spherical concave surface of a spherical ultrathin carbon-carbon screen blank; similarly, the radius value of the concave surface and the spherical groove of the female die is designed to be slightly larger than the radius value of the convex surface of the spherical ultrathin carbon-carbon screen blank. Through a method of reserving a rebound space in the direction opposite to the deformation direction, the problem that the size deviates from a design value due to rebound deformation of a curved surface area after a spherical ultrathin carbon-carbon screen blank is cured, formed and demolded is solved.

Description

Technical Field

[0001] This application relates to a layup molding structure for a spherical ultrathin carbon screen blank, belonging to the field of engine design technology. Background Technology

[0002] As deep space exploration progresses, traditional chemical propulsion systems are increasingly unable to meet the demands of deep space missions. To address this new challenge, long-life electric propulsion ion engines have become the preferred propulsion system for next-generation spacecraft. Their working principle is as follows: First, electrical energy is used to ionize the propellant. The ionized ions are then accelerated and extracted as they pass through a grid assembly with an ultra-thin screen structure, thereby generating long-lasting stable thrust. The grid assembly is the core component of the electric propulsion ion engine, and its design and manufacturing level directly determines the performance and lifespan of the propulsion system.

[0003] Conventional molybdenum metal gates have a lifespan of only 14,000 hours, far short of the 40,000-hour lifespan requirement for deep space exploration. To improve the structural performance of ultra-thin screen-structured gate components, further research into the application of advanced materials is necessary. Carbon-carbon composite materials possess advantages such as lightweight, high strength, low expansion, high temperature resistance, and resistance to ion sputtering, making them an ideal alternative to molybdenum metal as a gate component material for electric propulsion ion engines. Ion engines impose strict limitations on the thickness of the gate component. While molybdenum metal gates are generally designed in a planar shape, carbon-carbon composite materials have weaker impact toughness than molybdenum metal. If ultra-thin carbon-carbon screens adopt a planar design, they are more prone to brittle fracture than metallic materials when subjected to ion beam impacts. An arched surface can disperse the impact load across the entire structural surface, significantly reducing local stress concentration. This load dispersion characteristic allows the arched surface to transfer energy more evenly during impacts and reduces the likelihood of fracture. Therefore, to improve the impact toughness of ultra-thin carbon-carbon screens and ensure their service life, designing the central region as a more impact-resistant convex shape (such as a sphere) is a more feasible solution.

[0004] The fabrication process of ultrathin carbon-carbon screen grids can be broadly divided into three main steps: preform forming, CVD deposition (chemical vapor deposition) carbonization, and finishing. Among these, preform forming, as the first step, is particularly crucial, determining the difficulty of subsequent processes and the final product's molding effect. This stage mainly involves the placement and heat curing of the fiber-reinforced resin matrix composite material. Given the curved central region and planar edge region of the spherical ultrathin carbon-carbon screen preform, it is difficult to place the fiber-reinforced resin matrix composite material on the surface of the molding fixture structure using a winding method; therefore, a lay-up molding process must be employed.

[0005] For ultra-thin curved fiber-reinforced epoxy resin matrix composite structures with a thickness of less than 1 mm, the layup molding method will cause a certain degree of springback in the curved area after curing. Although this springback has little impact on the material strength, it should still be avoided as much as possible because the ultra-thin carbon screen preform has extremely high dimensional accuracy requirements. Therefore, a layup molding tooling structure that helps to reduce the springback deformation of fiber-reinforced epoxy resin matrix composites needs to be designed. Summary of the Invention

[0006] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a layup molding structure for a spherical ultrathin carbon-carbon screen blank. Using this structure, the spherical ultrathin carbon-carbon screen blank is laid up and molded. After curing and demolding, a spherical ultrathin carbon-carbon screen blank with controllable springback deformation and dimensional accuracy meeting the design requirements is obtained. This overcomes the problem that the curved area of ​​the spherical ultrathin carbon-carbon screen blank made of fiber-reinforced epoxy resin matrix composite material will exhibit springback deformation after curing.

[0007] The technical solution provided in this application is as follows:

[0008] Firstly, a spherical ultrathin carbon-carbon screen blank is provided, wherein the spherical ultrathin carbon-carbon screen blank consists of a central spherical surface, a transition rounded corner area, and an edge plane from the center to the edge. Compared with planar ultrathin carbon-carbon screens, this design increases the perforation area by designing the central area as a spherical surface, thereby improving the screen's filtration efficiency. At the same time, the arched spherical area improves the impact toughness of the ultrathin carbon-carbon screen, thereby increasing its service life.

[0009] Secondly, a layup molding structure for a spherical ultrathin carbon screen blank is provided, comprising: a male mold and a female mold; wherein the edge step of the male mold presses against the edge boss of the female mold.

[0010] In the aforementioned vapor-deposition densification structure of the ultrathin carbon-carbon screen preform, the male mold convex surface, from the center to the edge, consists of a spherical boss, a first transition rounded corner area, a first inclined annular surface, and an edge step, with the side of the male mold facing away from the convex surface being a plane. The spherical boss, the first transition rounded corner area, and the first inclined annular surface are all used for laying fiber-reinforced resin-based composite prepreg. The first transition rounded corner area is the transition region between the spherical boss and the first inclined annular surface. The edge step is used for alignment with the female mold.

[0011] In the above-mentioned vapor deposition densification structure of ultrathin carbon screen blank, the radius of the spherical boss is slightly larger than the radius of the spherical concave surface of the spherical ultrathin carbon screen blank, so as to reserve a certain rebound size for the spherical surface of the spherical ultrathin carbon screen blank, so that it can just reach the design radius value after rebound.

[0012] In the above-mentioned vapor deposition densification structure of ultrathin carbon screen blank, the first inclined annular surface is designed as an inclined surface with a certain inclination angle that gradually decreases in height from the inside to the outside, so as to reserve a certain rebound angle for the edge plane of the spherical ultrathin carbon screen blank after curing and demolding, so that it can just reach the design angle after rebounding.

[0013] In the above-mentioned vapor deposition densification structure of the ultrathin carbon screen preform, multiple threaded through holes are machined on the edge steps; the threaded through holes are used to screw screws into the bottom of the male mold after the spherical ultrathin carbon screen preform has been cured, thereby lifting the female mold and realizing product demolding.

[0014] After the male mold and the female mold are assembled, the gap height in the middle area is T2.

[0015] The gap T2 in the central region is the reserved space for molding the spherical ultra-thin carbon fiber screen blank, and the following constraints are satisfied between it and the spherical ultra-thin carbon fiber screen blank:

[0016] T1 = T2;

[0017] T2 = R2 - R1;

[0018] T2 = R3 - R4;

[0019] Wherein, T1 is the edge plane thickness of the spherical ultra-thin carbon screen blank, R1 is the radius of the convex corner of the transition zone of the spherical ultra-thin carbon screen blank, R2 is the radius of the concave corner of the transition zone of the spherical ultra-thin carbon screen blank, R3 is the radius of the convex surface of the spherical ultra-thin carbon screen blank, and R4 is the radius of the concave surface of the spherical ultra-thin carbon screen blank.

[0020] To ensure good filtration performance of the spherical ultrathin carbon screen blank, the radius R3 of the spherical convex surface of the spherical ultrathin carbon screen blank should meet the following constraints:

[0021] R3 > 1.2D3

[0022] D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultrathin carbon screen blank.

[0023] To ensure a good assembly effect for the spherical ultrathin carbon screen blank, the radial width L1 of the convex surface of the edge plane of the spherical ultrathin carbon screen blank should meet the following constraints:

[0024] L1 > 0.1D3

[0025] D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultrathin carbon screen blank.

[0026] The following empirical formula constraint condition is satisfied between the angle A2 between the first inclined annular surface and the central axis of the male mold and the angle A1 between the edge plane of the spherical ultrathin carbon screen blank and the central axis of the blank:

[0027]

[0028] Where D2 is the outer diameter of the transition zone of the spherical ultrathin carbon-carbon screen preform, ΔT is the difference between the maximum curing temperature of the composite material and room temperature, α2 is the average linear expansion coefficient of the resin material used in the spherical ultrathin carbon-carbon screen preform between room temperature and the maximum curing temperature of the composite material, and α1 is the average linear expansion coefficient of the unidirectional plate of the composite material used in the spherical ultrathin carbon-carbon screen preform along the fiber direction between room temperature and the maximum curing temperature of the composite material. This setting ensures that the edge plane of the spherical ultrathin carbon-carbon screen preform obtained after demolding remains flat after springback deformation.

[0029] The spherical radius R5 of the spherical boss and the spherical concave radius R4 of the spherical ultrathin carbon screen blank satisfy the following empirical formula constraint condition:

[0030]

[0031] Wherein, A2 is the angle between the first inclined annular surface and the central axis of the male mold, and A1 is the angle between the edge plane of the spherical ultra-thin carbon screen blank and the central axis of the blank.

[0032] The male mold and the spherical ultra-thin carbon fiber screen blank satisfy the following constraints:

[0033] D6 = D1 + 3.2R4cosA2;

[0034] D5 = D6 - L2;

[0035] D4 = D5 + D3 - D2;

[0036] R7 = R2

[0037] Wherein, D6 is the diameter of the first inclined annular edge of the male mold, D1 is the diameter of the spherical ultra-thin carbon screen blank, D5 is the diameter of the first transition rounded corner area of ​​the male mold, L2 is the radial width of the concave surface of the edge plane of the spherical ultra-thin carbon screen blank, D4 is the diameter of the spherical boss edge of the male mold, D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultra-thin carbon screen blank, D2 is the outer diameter of the transition area of ​​the spherical ultra-thin carbon screen blank, R7 is the radius of the first transition rounded corner area, and R2 is the radius of the concave surface rounded corner of the transition area of ​​the spherical ultra-thin carbon screen blank.

[0038] In the aforementioned vapor-deposition densification structure of the ultrathin carbon-carbon screen preform, the concave surface of the female mold consists of a spherical groove, a second transition rounded corner area, a second inclined annular surface, and an edge boss, arranged sequentially from the center to the edge. The surface of the female mold facing away from the male mold is a plane. The spherical groove, the second transition rounded corner area, and the second inclined annular surface are all used to compress the fiber-reinforced resin-based composite prepreg. The second transition rounded corner area is the transition region between the spherical groove and the second inclined annular surface. The edge boss is used for alignment with the male mold.

[0039] In the above-mentioned vapor-deposition densification structure of the ultra-thin carbon screen blank, the radius of the spherical groove is equal to the sum of the radius of the spherical boss and the thickness of the spherical surface of the ultra-thin carbon screen blank, that is, slightly larger than the radius of the convex surface of the spherical surface of the ultra-thin carbon screen blank, so as to reserve a certain rebound size for the spherical surface of the ultra-thin carbon screen blank, so that it can just reach the design radius value after rebound.

[0040] In the above-mentioned vapor deposition densification structure of the ultrathin carbon screen blank, the second inclined annular surface is designed as an inclined surface with a certain inclination angle that gradually decreases in height from the inside to the outside, so as to reserve a certain rebound angle for the edge plane of the spherical ultrathin carbon screen blank after curing and demolding, so that it can just reach the design angle after rebound; wherein, the inclination angle of the second inclined annular surface is equal to the inclination angle of the first inclined annular surface.

[0041] In the above-mentioned vapor-deposition densification structure of ultrathin carbon screen blank, the surface of the edge boss is planar.

[0042] The female mold and the spherical ultra-thin carbon fiber screen blank satisfy the following constraints:

[0043] D 10 =D1+3.2R4cosA3;

[0044] D9 = D 10 -L1;

[0045] D8 = D3;

[0046] R8 = R1

[0047] Among them, D 10 D1 is the diameter of the edge of the second inclined annular surface, D3 is the diameter of the spherical ultra-thin carbon screen blank, D9 is the diameter of the edge of the second transition rounded corner area, L1 is the radial width of the convex surface of the edge plane of the spherical ultra-thin carbon screen blank, D8 is the diameter of the edge of the spherical groove, D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultra-thin carbon screen blank, R8 is the radius of the rounded corner of the second transition rounded corner area, and R1 is the radius of the rounded corner of the convex surface of the transition area of ​​the spherical ultra-thin carbon screen blank.

[0048] The following constraints are satisfied between the angle A3 between the second inclined toroidal surface and the central axis of the female mold and the angle A2 between the first inclined toroidal surface and the central axis of the male mold:

[0049] A3 = A2

[0050] The spherical radius R6 of the spherical groove and the spherical radius R5 of the spherical boss satisfy the following constraint condition:

[0051] R6 = R5 + T2

[0052] T2 is the height of the gap between the male and female molds in the middle area after assembly.

[0053] In summary, this application includes at least the following beneficial technical effects:

[0054] This invention solves the problem of dimensional deviation from the design value caused by springback deformation in the curved area after the spherical ultrathin carbon screen blank is demolded, by designing the first inclined surface of the male mold and the second inclined surface of the female mold in the form of a certain inclined angle. The radius of the spherical boss of the male mold is designed to be slightly larger than the radius of the spherical concave surface of the spherical ultrathin carbon screen blank, and similarly, the radius of the spherical groove of the female mold is designed to be slightly larger than the radius of the spherical convex surface of the spherical ultrathin carbon screen blank. By reserving springback space in the opposite direction of deformation, the invention solves the problem of dimensional deviation from the design value caused by springback deformation in the curved area after the spherical ultrathin carbon screen blank is demolded. Attached Figure Description

[0055] Figure 1 This is a top view of the ultrathin carbon screen blank sample according to an embodiment of the present invention;

[0056] Figure 2 for Figure 1 Sectional view of section AA;

[0057] Figure 3 This is an assembly diagram of the layup molding structure according to an embodiment of the present invention;

[0058] Figure 4 This is a top view of the male mold of the layup molding structure according to an embodiment of the present invention;

[0059] Figure 5 for Figure 4 View from direction B;

[0060] Figure 6 This is a bottom view of the female mold of the layup molding structure according to an embodiment of the present invention;

[0061] Figure 7 for Figure 6 Sectional view of the CC section. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments disclosed in this application will be described in further detail below with reference to the accompanying drawings.

[0063] This application discloses a layup molding structure for a spherical ultrathin carbon-carbon screen blank. By designing the first inclined surface of the male mold and the second inclined surface of the female mold with a certain inclination angle, and by designing the radius of the spherical boss of the male mold to be slightly larger than the radius of the spherical concave surface of the spherical ultrathin carbon-carbon screen blank, similarly, the radius of the spherical groove of the female mold to be slightly larger than the radius of the spherical convex surface of the spherical ultrathin carbon-carbon screen blank. By reserving springback space in the opposite direction of deformation, the problem of springback deformation in the curved area after demolding of the spherical ultrathin carbon-carbon screen blank, leading to dimensional deviations from the design values, is solved.

[0064] The layup molding structure in this embodiment is for... Figure 1 , Figure 2 The spherical ultrathin carbon screen blank shown is designed.

[0065] The spherical ultrathin carbon screen blank consists of a spherical surface, a transition zone, and an edge plane (formed at the position of the first inclined annular surface 9) from the middle to the edge.

[0066] like Figure 1 , Figure 2 As shown, the spherical ultrathin carbon screen blank designed in this embodiment has the following dimensions: diameter D1, outer diameter of transition zone D2, inner diameter of transition zone D3, edge plane thickness T1, radial width of convex edge plane L1, radial width of concave edge plane L2, angle between edge plane and blank center axis A1, radius of convex spherical surface R3, radius of concave spherical surface R4, radius of convex corner of transition zone R1, and radius of concave corner of transition zone R2.

[0067] like Figure 3 As shown, the layup molding structure includes a male mold 1 and a female mold 2. The edge step of the male mold 1 presses against the concave edge boss of the female mold 2; after the male mold 1 and the female mold 2 are assembled, the gap height in the middle area is T2.

[0068] The gap in the middle area is the reserved space for molding the spherical ultra-thin carbon screen blank, and it satisfies the following constraints with the spherical ultra-thin carbon screen blank designed in this embodiment:

[0069] T1 = T2;

[0070] T2 = R1 - R2;

[0071] T2 = R3 - R4

[0072] like Figure 4 and Figure 5As shown, the convex surface of the male mold 1 consists of a spherical boss 7, a first transition rounded corner area 8, a first inclined annular surface 9, and an edge step 10, arranged sequentially from the center to the edge. The surface of the male mold 1 facing away from the convex surface is a plane. The edge diameter of the spherical boss 7 is D4, the edge diameter of the first transition rounded corner area 8 is D5, the edge diameter of the first inclined annular surface 9 is D6, and the edge diameter of the edge step 10 is D7. The radius of the rounded corner of the first transition rounded corner area 8 is R7. The radius of the spherical boss 7 is R5. The angle between the first inclined annular surface 9 and the central axis of the male mold 1 is A2. The edge step 10 is evenly machined with a first threaded through hole 3, a second threaded through hole 4, a third threaded through hole 5, and a fourth threaded through hole 6 along the circumferential direction. These are used to lift the female mold 2 by screwing in screws from the bottom of the male mold 1 after the spherical ultra-thin carbon screen blank has solidified, thereby achieving demolding.

[0073] The following empirical formula constraint conditions must be satisfied between the angle A2 between the first inclined toroidal surface 9 and the central axis of the male mold 1 and the angle A1 between the edge plane of the spherical ultrathin carbon screen blank and the central axis of the blank:

[0074]

[0075] In the formula, A2 is the angle between the first inclined annular surface 9 and the central axis of the male mold 1; A1 is the angle between the edge plane of the spherical ultra-thin carbon screen blank and the central axis of the blank; D2 is the outer diameter of the transition zone of the spherical ultra-thin carbon screen blank; R4 is the radius of the concave surface of the spherical ultra-thin carbon screen blank; α2 is the average linear expansion coefficient of the resin material used in the spherical ultra-thin carbon screen blank between room temperature and the highest temperature of the composite material curing regime; α1 is the average linear expansion coefficient of the unidirectional plate of the composite material used in the spherical ultra-thin carbon screen blank along the fiber direction between room temperature and the highest temperature of the composite material curing regime; ΔT is the difference between the highest temperature of the composite material curing regime and room temperature.

[0076] The spherical radius R5 of the spherical boss 7 and the spherical concave radius R4 of the spherical ultrathin carbon screen blank satisfy the following empirical formula constraint condition:

[0077]

[0078] In the formula, R5 is the radius of the spherical boss 7; R4 is the radius of the concave surface of the spherical ultra-thin carbon screen blank; A2 is the angle between the first inclined annular surface 9 and the central axis of the male mold 1; and A1 is the angle between the edge plane of the spherical ultra-thin carbon screen blank and the central axis of the blank.

[0079] The following constraints must be satisfied between the male mold 1 and the spherical ultrathin carbon screen blank designed in this embodiment:

[0080] D6 = D1 + 3.2R4cosA2;

[0081] D5 = D6 - L2;

[0082] D4 = D5 + D3 - D2;

[0083] R7 = R2

[0084] like Figure 6 and Figure 7 As shown, the concave surface of the female mold 2 consists of a spherical groove 11, a second transition rounded corner area 12, a second inclined annular surface 13, and an edge boss 14, arranged sequentially from the center to the edge. The surface of the female mold 2 facing away from the concave surface is flat. The edge diameter of the spherical groove 11 is D8, the edge diameter of the second transition rounded corner area 12 is D9, and the edge diameter of the second inclined annular surface 13 is D... 10 The edge diameter of edge boss 14 is D. 11 The radius of the rounded corner of the second transition rounded corner area 12 is R8; the radius of the spherical groove 11 is R6; the angle between the second inclined annular surface 13 and the central axis of the female mold 2 is A3.

[0085] The female mold 2 and the spherical ultrathin carbon screen blank designed in this embodiment satisfy the following constraints:

[0086] D 10 =D1+3.2R4cosA3;

[0087] D9 = D 10 -L1;

[0088] D8 = D3;

[0089] R8 = R1

[0090] The following constraints must be satisfied between the angle A3 between the second inclined torus 13 and the central axis of the female mold 2 and the angle A2 between the first inclined torus 9 and the central axis of the male mold 1:

[0091] A3 = A2

[0092] The spherical radius R6 of the spherical groove 11 and the spherical radius R5 of the spherical boss 7 satisfy the following constraint condition:

[0093] R6 = R5 + T2

[0094] Using the structure proposed in this invention, the CVD deposition process of ultrathin carbon-carbon screen preforms can be achieved by... Figures 4-6The male and female molds shown are used to lay up and mold the fiber-reinforced resin matrix composite material. By designing the first inclined surface of the male mold and the second inclined surface of the female mold with a certain inclination angle, and by designing the radius of the spherical boss of the male mold to be slightly larger than the radius of the spherical concave surface of the spherical ultra-thin carbon fiber screen blank, similarly, the radius of the spherical groove of the female mold is designed to be slightly larger than the radius of the spherical convex surface of the spherical ultra-thin carbon fiber screen blank. By reserving springback space in the opposite direction of deformation, the problem of springback deformation in the curved area after demolding of the spherical ultra-thin carbon fiber screen blank, causing dimensional deviations from the design values, is solved.

[0095] Example 1

[0096] The design dimensions of the spherical ultrathin carbon screen blank in this embodiment are: D1 = 300mm, D2 = 235mm, D3 = 228mm, T1 = 0.6mm, A1 = 90°, R2 = 9.8mm, R1 = 9.2mm, R3 = 510.3mm, R4 = 509.7mm, L1 = 32.5mm, L2 = 34.5mm.

[0097] The design dimensions of the female mold for the spherical ultrathin carbon screen blank layup molding structure in this embodiment are: D8 = 228mm, D9 = 234.19mm, D... 10 =268.69mm, D 11 =320mm, R6=510.1mm, R8=9.2mm, A3=88.9°.

[0098] The design dimensions of the male mold for the spherical ultra-thin carbon screen blank layup molding structure in this embodiment are: D4 = 227.19 mm, D5 = 234.19 mm, D6 = 268.69 mm, D7 = 320 mm, R5 = 509.5 mm, R7 = 9.8 mm, A2 = 91.1°.

[0099] A fiber-reinforced resin-based composite material is laid up on a female mold. After the layup is complete, the male and female molds are joined and cured. After curing, the material is cooled to room temperature and demolded to obtain a spherical ultra-thin carbon fiber screen preform. The preform is left to stand for 1-2 hours (during which the preform springs back) to allow it to fully spring back. The key parameters of the preform are measured as follows: A1 = 89.8°, R3 = 510.16 mm, R4 = 509.63 mm. The error does not exceed 0.25%, therefore, the layup molding structure design method for the spherical ultra-thin carbon fiber screen preform provided by this invention is reliable.

[0100] Based on the design dimensions of the female and male molds in Example 1, a layup molding structure for a spherical ultrathin carbon screen blank was fabricated, and a sample conforming to the design dimensions of the spherical ultrathin carbon screen blank in Example 1 was prepared using this layup molding structure.

[0101] Holes were drilled in the spherical region of the spherical ultrathin carbon-carbon screen blank sample (the holes were evenly distributed on the spherical surface, with a hole diameter of 2 mm and a total hole area of ​​6120–6160 mm²). 2 A spherical ultrathin carbon fiber screen was obtained, and compared with a planar ultrathin carbon fiber screen with the same outer diameter of the screen hole area (the holes are evenly distributed on the spherical surface, the hole diameter is 2 mm, and the total hole area is 5580-5620 mm²). 2 The bending resistance, impact resistance, and estimated service life are all improved.

[0102] The performance of the spherical ultrathin carbon screen obtained in the above embodiments was tested and compared with that of a planar ultrathin carbon screen with the same outer diameter of the screen hole area. The results are shown in Table 1.

[0103] Table 1 Performance Test Table

[0104]

[0105] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

[0106] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A spherical ultrathin carbon fiber screen blank, characterized in that: The spherical ultrathin carbon screen blank consists of a spherical surface, a transition rounded corner area, and an edge plane from the middle to the edge. The edge plane has a ring structure, and the transition rounded corner area is a rounded transition structure between the spherical surface and the edge plane.

2. The spherical ultrathin carbon screen blank according to claim 1, characterized in that, The radius R3 of the spherical convex surface of the spherical ultrathin carbon screen blank should satisfy the following constraint conditions: R3 > 1.2D3 D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultrathin carbon screen blank.

3. The spherical ultrathin carbon screen blank according to claim 1, characterized in that, The radial width L1 of the convex surface of the edge plane of the spherical ultrathin carbon screen blank should meet the following constraints: L1 > 0.1D3 D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultrathin carbon screen blank.

4. The spherical ultrathin carbon screen blank according to claim 1, characterized in that: The spherical ultrathin carbon screen blank is obtained by laying, molding, and curing fiber-reinforced resin matrix composite material on a layup molding structure.

5. The layup molding structure of a spherical ultrathin carbon screen blank according to any one of claims 1-4, characterized in that: Includes a positive mold (1) and a negative mold (2); The surface of the male mold (1) consists of a spherical boss (7), a first transition rounded corner area (8), a first inclined annular surface (9), and an edge step (10) from the middle to the edge. The spherical boss (7), the first transition rounded corner area (8), and the first inclined annular surface (9) are all used to lay fiber-reinforced resin-based composite prepreg. The first transition rounded corner area (8) is the transition area between the spherical boss (7) and the first inclined annular surface (9). The edge step (10) is used to align with the female mold (2). The female mold (2) has a spherical groove (11), a second transition rounded corner area (12), a second inclined annular surface (13), and an edge boss (14) on one side surface from the middle to the edge. The spherical groove (11), the second transition rounded corner area (12), and the second inclined annular surface (13) are all used to compress the fiber-reinforced resin-based composite prepreg. The second transition rounded corner area (12) is the transition area between the spherical groove (11) and the second inclined annular surface (13). The edge boss (14) is used to align with the edge step (10) of the male mold (1).

6. The layup molding structure of a spherical ultrathin carbon screen blank according to claim 5, characterized in that: After the male mold (1) and female mold (2) are assembled, the gap height in the middle area is T2, T1 = T2; T2 = R2 - R1; T2 = R3 - R4; Wherein, T1 is the edge plane thickness of the spherical ultra-thin carbon screen blank, R1 is the radius of the convex corner of the transition zone of the spherical ultra-thin carbon screen blank, R2 is the radius of the concave corner of the transition zone of the spherical ultra-thin carbon screen blank, R3 is the radius of the convex surface of the spherical ultra-thin carbon screen blank, and R4 is the radius of the concave surface of the spherical ultra-thin carbon screen blank.

7. The layup molding structure of a spherical ultrathin carbon screen blank according to claim 5, characterized in that: Multiple threaded through holes are evenly distributed along the circumference of the edge step (10), which are used to screw screws into the male mold (1) from the side away from the female mold (2) after the spherical ultra-thin carbon screen blank is cured, thereby lifting the female mold (2) and realizing demolding.

8. The layup molding structure of a spherical ultrathin carbon screen blank according to claim 5, characterized in that: The following constraints are satisfied between the angle A2 between the first inclined annular surface (9) and the central axis of the male mold (1) and the angle A1 between the edge plane of the spherical ultrathin carbon screen blank and the central axis of the blank: Where D2 is the outer diameter of the transition zone of the spherical ultrathin carbon screen blank, ΔT is the difference between the highest temperature of the composite curing regime and room temperature, α2 is the average linear expansion coefficient of the resin material used in the spherical ultrathin carbon screen blank between room temperature and the highest temperature of the composite curing regime, and α1 is the average linear expansion coefficient of the unidirectional plate of the composite material used in the spherical ultrathin carbon screen blank along the fiber direction between room temperature and the highest temperature of the composite curing regime. The following constraint condition must be satisfied between the angle A3 between the second inclined toroidal surface and the central axis of the female mold and the angle A2 between the first inclined toroidal surface and the central axis of the male mold: A3 = A2.

9. The layered molding structure of a spherical ultrathin carbon screen blank according to claim 5, characterized in that: The spherical radius R5 of the spherical boss and the radius R4 of the lower surface of the spherical ultrathin carbon screen blank satisfy the following constraint condition: Wherein, A2 is the angle between the first inclined annular surface and the central axis of the male mold, and A1 is the angle between the edge plane of the spherical ultra-thin carbon screen blank and the central axis of the blank; The following constraint condition must be satisfied between the spherical radius R6 of the spherical groove and the spherical radius R5 of the spherical boss: R6 = R5 + T2.

10. The layered molding structure of a spherical ultrathin carbon screen blank according to claim 5, characterized in that: The male mold (1) and the spherical ultrathin carbon screen blank satisfy the following constraints: D6 = D1 + 3.2R4cosA2; D5 = D6 - L2; D4 = D5 + D3 - D2; R7 = R2 Wherein, D6 is the diameter of the first inclined annular edge of the male mold, D1 is the diameter of the spherical ultra-thin carbon screen blank, D5 is the diameter of the first transition rounded corner area of ​​the male mold, L2 is the radial width of the concave surface of the edge plane of the spherical ultra-thin carbon screen blank, D4 is the diameter of the spherical boss edge of the male mold, D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultra-thin carbon screen blank, D2 is the outer diameter of the transition area of ​​the spherical ultra-thin carbon screen blank, R7 is the radius of the first transition rounded corner area, and R2 is the radius of the concave surface of the transition area of ​​the spherical ultra-thin carbon screen blank. The female mold (2) and the spherical ultrathin carbon screen blank satisfy the following constraints: D 10 =D1+3.2R4cosA3; D9=D 10 -L1; D8 = D3; R8 = R1 Among them, D 10 D1 is the diameter of the edge of the second inclined annular surface, D3 is the diameter of the spherical ultra-thin carbon screen blank, D9 is the diameter of the edge of the second transition rounded corner area, L1 is the radial width of the convex surface of the edge plane of the spherical ultra-thin carbon screen blank, D8 is the diameter of the edge of the spherical groove, D3 is the inner diameter of the transition rounded corner area of ​​the spherical ultra-thin carbon screen blank, R8 is the radius of the rounded corner of the second transition rounded corner area, and R1 is the radius of the rounded corner of the convex surface of the transition area of ​​the spherical ultra-thin carbon screen blank.

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