Ceramic matrix composite material control surface framework forming method

Abstract

The invention discloses a ceramic matrix composite control plane framework forming method. The method comprises the following steps that S1, cloth is cut; based on the size and the thickness of the control plane framework prefabricated body, carbon cloth is subjected to cloth cutting treatment, and cut carbon cloth is obtained; s2, laying a control plane framework prefabricated body; s3, sewing and die assembly are carried out; step S4, depositing and densifying; carrying out vapor deposition on the unequal-thickness control surface skeleton prefabricated body, and enlarging the unequal-thickness control surface skeleton prefabricated body; s5, machining is conducted, specifically, machining is conducted on the unequal-thickness control plane framework prefabricated body with the increased density, and a control plane framework part is obtained; on the basis of a carbon fiber cloth two-dimensional lamination forming mode, integrated forming of the control plane framework prefabricated body is achieved, compared with split forming, part assembling and riveting do not need to be conducted on a product in the subsequent ceramic matrix composite material preparation process, interlayer bonding between a framework box and a skin is high, and cracking is not likely to occur in the deposition process.

Description

Technical Field

[0001] This invention relates to the field of rudder surface skeleton forming technology, and specifically to a method for forming a ceramic matrix composite rudder surface skeleton. Background Technology

[0002] Ceramic matrix composites have advantages such as high temperature resistance and low density, and are widely used in aerospace and other fields.

[0003] Traditional C / SiC ceramic matrix composite rudder skeletons primarily employ a split molding method, fabricating skin and skeleton components. These components are then riveted together using C / SiC ceramic matrix composite connectors, with CVI deposition used to fill the gaps between the rivets and the parts, achieving a welding effect. This connection method, besides compromising the structural strength of the parts, is unsuitable for parts with small and narrow connection areas. A small and narrow connection area limits the number of connectors required, and under high loads, the welded joints are prone to fracture.

[0004] In existing technologies, to address the risk of weld breakage, the rudder surface frame typically employs a monolithic layup. However, this approach is also limited by the small and narrow connection area, resulting in fewer Z-direction stitched fibers and a high risk of cracking between the frame box and the skin during the molding process. This invention provides a rudder surface frame molding process to solve the problem of weak bonding between the frame rudder surface box and the skin layer, leading to easy cracking during the deposition process. Summary of the Invention To address the aforementioned problems in the prior art, this invention provides a method for molding a ceramic matrix composite rudder skeleton, which solves the problem of easy cracking between the skeleton box and the skin of existing rudder skeletons during the molding process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for forming a ceramic matrix composite rudder surface skeleton includes the following steps: Step S1: Cutting the fabric; Based on the size and thickness of the prefabricated rudder surface frame, the carbon fabric is cut to obtain the cut carbon fabric. Step S2: Laying up the prefabricated body of the rudder surface frame; laying up multiple layers of cut carbon cloth to obtain a bottom layer of uniform thickness prefabricated body, a first bottom layer of unequal thickness box prefabricated body and a second bottom layer of unequal thickness box prefabricated body, a first middle layer of unequal thickness wrapping box prefabricated body and a second middle layer of unequal thickness wrapping box prefabricated body, and an upper layer of unequal thickness prefabricated body. Step S3, sewing and mold closing; the preform is sewn, and after sewing, the edges of the preform are locked. Then, the preform is fixed by closing the upper and lower molds to obtain the unequal thickness rudder surface skeleton preform. Step S4, Deposition and Densification: Perform vapor deposition on the prefabricated rudder surface skeleton of unequal thickness to increase the size of the prefabricated rudder surface skeleton of unequal thickness; Step S5: Machining. The prefabricated rudder surface frame with increased density and uneven thickness is machined to obtain the rudder surface frame part.

[0006] This invention is based on a two-dimensional carbon fiber fabric lamination molding method to achieve integrated molding of the rudder surface skeleton preform. Compared with split molding, there is no need to assemble and rivet parts in the subsequent ceramic matrix composite material preparation process. The interlayer bonding between the skeleton box and the skin is strong, and cracking is not easy to occur during the deposition process.

[0007] Furthermore, the method for preparing the bottom layer uniform thickness fabric preform in step S2 is as follows: multiple layers of cut carbon cloth are laid on the lower mold to obtain the bottom layer uniform thickness fabric preform.

[0008] Further, the method for preparing the bottom layer unequal thickness box preform in step S2 is as follows: place the first inner mold and the second inner mold on the bottom layer uniform thickness fabric preform, and lay multiple layers of cut carbon cloth on the first inner mold and the second inner mold respectively to obtain the first bottom layer unequal thickness box preform and the second bottom layer unequal thickness box preform.

[0009] Furthermore, the method for preparing the intermediate layer unequal thickness packaging box preform in step S2 is as follows: multiple layers of cut carbon cloth are laid on the first bottom layer unequal thickness box preform and the second bottom layer unequal thickness box preform to obtain the first intermediate layer unequal thickness packaging box preform and the second intermediate layer unequal thickness packaging box preform.

[0010] Further, the method for preparing the upper layer of unequal thickness fabric preform in step S2 is as follows: the box preform with the first inner mold and the second inner mold is placed on the bottom layer of equal thickness fabric preform with the lower mold to obtain the preform base; multiple layers of cut carbon cloth are then laid on the preform base to obtain the upper layer of unequal thickness fabric preform.

[0011] Furthermore, in step S2, during the preparation of the preform, areas with thicker walls are padded with carbon cloth, and the padded carbon cloth is evenly added to carbon cloth of equal thickness.

[0012] Further, in step S4, the unequal thickness rudder surface skeleton preform is subjected to interface layer deposition, high temperature treatment and silicon carbide substrate deposition treatment in sequence to obtain an unequal thickness rudder surface skeleton preform with a density greater than 1.8 g / cm3.

[0013] This invention discloses a method for forming a ceramic matrix composite rudder surface skeleton, the beneficial effects of which are: 1. This invention is based on the two-dimensional lamination of carbon fiber cloth to realize the integrated molding of the rudder surface skeleton preform. Compared with split molding, there is no need to assemble and rivet the parts in the subsequent ceramic matrix composite material preparation process. The interlayer bonding between the skeleton box and the skin is strong and cracking is not easy to occur during the deposition process.

[0014] 2. This invention increases the Z-direction stitching fibers in the connection area by increasing the connection area between the box and the skin during the overall layup, thereby strengthening the interlayer bonding between the skeleton box and the skin and making it less prone to cracking during the deposition process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a method for forming a ceramic matrix composite rudder surface skeleton according to the present invention.

[0016] Figure 2 This is a schematic diagram of another angle of the ceramic matrix composite rudder surface skeleton forming method of the present invention.

[0017] Figure 3 This is a schematic diagram of the structure of the prefabricated rudder surface skeleton of the present invention.

[0018] Figure 4 This is a schematic diagram of the structure of the bottom layer uniform thickness prefabricated body of the present invention.

[0019] Figure 5 This is a schematic diagram of the structure of the first bottom layer unequal thickness box preform and the second bottom layer unequal thickness box preform of the present invention.

[0020] Figure 6 This is a schematic diagram of the structure of the first and second intermediate layer unequal thickness wrapping box preforms of the present invention.

[0021] Figure 7 This is a schematic diagram of the upper layer of the unequal thickness prefabricated fabric of the present invention.

[0022] Figure 8 This is a schematic diagram of the molded structure of the prefabricated rudder surface skeleton of the present invention.

[0023] Among them, 100 is the prefabricated body of the rudder surface frame; 101 is the prefabricated body of the bottom layer of uniform thickness fabric; 102 is the prefabricated body of the first bottom layer of unequal thickness box; 103 is the prefabricated body of the second bottom layer of unequal thickness box; 104 is the prefabricated body of the first middle layer of unequal thickness wrapping box; 105 is the prefabricated body of the second middle layer of unequal thickness wrapping box; 106 is the prefabricated body of the upper layer of unequal thickness fabric; 107 is the lower mold; 108 is the first inner mold; and 109 is the second inner mold. Detailed Implementation The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0024] Example 1 refer to Figures 1-8 This embodiment provides a method for molding a ceramic matrix composite rudder surface skeleton, the purpose of which is to solve the problem of easy cracking between the skeleton box and the skin of the existing rudder surface skeleton during the molding process. The specific structure of this embodiment will be described in detail below.

[0025] A method for forming a ceramic matrix composite rudder surface skeleton includes the following steps: Step S1, Fabric cutting; Based on the dimensions and thickness of the rudder surface frame prefabricated body 100, the carbon fabric is cut to obtain the cut carbon fabric. Step S2: Lay up the prefabricated body 100 of the rudder surface frame; lay up multiple layers of cut carbon cloth to obtain the bottom layer uniform thickness prefabricated body 101, the first bottom layer unequal thickness box prefabricated body 102 and the second bottom layer unequal thickness box prefabricated body 103, the first middle layer unequal thickness wrapping box prefabricated body 104 and the second middle layer unequal thickness wrapping box prefabricated body 105, and the top layer unequal thickness uniform cloth prefabricated body 106. Specifically, the method for preparing the bottom layer uniform thickness fabric preform 101 in step S2 is as follows: multiple layers of cut carbon cloth are laid on the lower mold 107 to obtain the bottom layer uniform thickness fabric preform 101. In the process of preparing the preform, carbon cloth is used to pad areas with thick walls, and the padding carbon cloth is evenly added to the uniform thickness carbon cloth.

[0026] The method for preparing the bottom layer unequal thickness box preform in step S2 is as follows: the first inner mold 108 and the second inner mold 109 are placed on the bottom layer uniform thickness fabric preform 101, and multiple layers of cut carbon cloth are laid on the first inner mold 108 and the second inner mold 109 respectively to obtain the first bottom layer unequal thickness box preform 102 and the second bottom layer unequal thickness box preform 103. In the process of preparing the preform, the area with more wall thickness is padded with carbon cloth, and the padded carbon cloth is evenly added to the uniform thickness carbon cloth. The method for preparing the intermediate layer unequal thickness wrapping box preform in step S2 is as follows: multiple layers of cut carbon cloth are laid on the first bottom layer unequal thickness box preform and the second bottom layer unequal thickness box preform 103 to obtain the first intermediate layer unequal thickness wrapping box preform 104 and the second intermediate layer unequal thickness wrapping box preform 105. In the process of preparing the preform, the area with more wall thickness is padded with carbon cloth, and the padded carbon cloth is evenly added to the carbon cloth of equal thickness. The method for preparing the upper layer of unequal thickness solid fabric preform 106 in step S2 is as follows: the box preform with the first inner mold and the second inner mold is placed on the bottom layer of equal thickness solid fabric preform 101 with the lower mold to obtain the preform base; multiple layers of cut carbon cloth are then laid on the preform base to obtain the upper layer of unequal thickness solid fabric preform 106. During the preparation of the preform, carbon cloth is used to pad areas with thicker walls, and the padded carbon cloth is evenly added to the equal thickness carbon cloth. Step S3, sewing and mold closing; based on the sewing holes and sewing grooves on the mold, the preform is sewn, and after sewing, the edges of the preform are locked. Then, the preform is fixed by closing the upper mold and the lower mold to obtain the unequal thickness rudder surface skeleton preform. In this embodiment, the mold includes an upper mold, a lower mold 107, and a middle pressing mold, all made of graphite. The upper mold, the lower mold, and the middle pressing mold are all provided with sewing holes and sewing grooves to sew the preform.

[0027] Step S4, Deposition and Densification: Perform vapor deposition on the prefabricated rudder surface skeleton of unequal thickness to increase the size of the prefabricated rudder surface skeleton of unequal thickness; Specifically, in step S4, the unequal thickness rudder surface skeleton preform is subjected to interface layer deposition, high temperature treatment and silicon carbide substrate deposition treatment in sequence to obtain an unequal thickness rudder surface skeleton preform with a density greater than 1.8 g / cm3.

[0028] Step S5: Machining. The prefabricated rudder surface frame with increased density and uneven thickness is machined to obtain the rudder surface frame part.

[0029] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A method for forming a ceramic matrix composite rudder surface skeleton, characterized in that, Includes the following steps: Step S1: Cutting the fabric; Based on the size and thickness of the prefabricated rudder surface frame, the carbon fabric is cut to obtain the cut carbon fabric. Step S2: Laying up the prefabricated body of the rudder surface frame; laying up multiple layers of cut carbon cloth to obtain a bottom layer of uniform thickness prefabricated body, a first bottom layer of unequal thickness box prefabricated body and a second bottom layer of unequal thickness box prefabricated body, a first middle layer of unequal thickness wrapping box prefabricated body and a second middle layer of unequal thickness wrapping box prefabricated body, and an upper layer of unequal thickness prefabricated body. Step S3, sewing and mold closing; the preform is sewn, and after sewing, the edges of the preform are locked. Then, the preform is fixed by closing the upper and lower molds to obtain the unequal thickness rudder surface skeleton preform. Step S4, Deposition and Densification: Perform vapor deposition on the prefabricated rudder surface skeleton of unequal thickness to increase the size of the prefabricated rudder surface skeleton of unequal thickness; Step S5: Machining. The prefabricated rudder surface frame with increased density and uneven thickness is machined to obtain the rudder surface frame part.

2. The method for forming a ceramic matrix composite rudder surface skeleton according to claim 1, characterized in that: The method for preparing the bottom layer uniform thickness prefabricated body in step S2 is as follows: multiple layers of cut carbon cloth are laid on the lower mold to obtain the bottom layer uniform thickness prefabricated body.

3. The method for forming a ceramic matrix composite rudder surface skeleton according to claim 2, characterized in that: The method for preparing the bottom layer unequal thickness box preform in step S2 is as follows: place the first inner mold and the second inner mold on the bottom layer uniform thickness fabric preform, and lay multiple layers of cut carbon cloth on the first inner mold and the second inner mold respectively to obtain the first bottom layer unequal thickness box preform and the second bottom layer unequal thickness box preform.

4. The method for forming a ceramic matrix composite rudder surface skeleton according to claim 3, characterized in that: The method for preparing the intermediate layer unequal thickness wrapping box preform in step S2 is as follows: multiple layers of cut carbon cloth are laid on the first bottom layer unequal thickness box preform and the second bottom layer unequal thickness box preform to obtain the first intermediate layer unequal thickness wrapping box preform and the second intermediate layer unequal thickness wrapping box preform.

5. The method for forming a ceramic matrix composite rudder surface skeleton according to claim 4, characterized in that: The method for preparing the upper layer of unequal-thickness solid fabric preform in step S2 is as follows: the box preform with the first inner mold and the second inner mold is placed on the bottom layer of equal-thickness solid fabric preform with the lower mold to obtain the preform base; multiple layers of cut carbon cloth are then laid on the preform base to obtain the upper layer of unequal-thickness solid fabric preform.

6. The method for forming a ceramic matrix composite rudder surface skeleton according to any one of claims 2-5, characterized in that: In the process of preparing the preform in step S2, carbon cloth is used to pad areas with thick walls, and the padding carbon cloth is evenly added to carbon cloth of equal thickness.

7. The method for forming a ceramic matrix composite rudder surface skeleton according to claim 1, characterized in that: In step S4, the prefabricated rudder surface skeleton of unequal thickness is subjected to interface layer deposition, high-temperature treatment, and silicon carbide substrate deposition treatment in sequence to obtain a density greater than 1.8 g / cm³. 3 Precast rudder surface frame with unequal thickness.

Images