Composite material woven bulkhead and preparation process thereof

Abstract

The invention provides a bulkhead woven by a composite material and a preparation process thereof, and belongs to the field of bulkhead preparation, and the preparation process comprises the following steps: splicing two half mandrels into a whole mandrel with a rectangular cross section; clamping the whole core mold, and knitting fiber yarns on the whole core mold through a three-dimensional knitting machine, so as to prepare a prefabricated body with a rectangular section; heating the prefabricated body, and carrying out preliminary curing on the prefabricated body, so as to prepare a preliminarily cured prefabricated body; after the preliminarily solidified prefabricated body is cooled, the preliminarily solidified prefabricated body is divided into two U-shaped prefabricated bodies along the cutting plane; one vertical surface of the U-shaped prefabricated body is turned over by more than 90 degrees; and the folded U-shaped prefabricated body is cured again, so that the bulkhead is prepared. According to the invention, the braiding machine is used for braiding the prefabricated body, preliminarily curing the prefabricated body, cutting the prefabricated body, folding the prefabricated body and re-curing the prefabricated body, so that fiber wrinkles, fiber gaps and fiber angles at the bent part of the bulkhead can be better controlled.

Description

Technical Field

[0001] The invention belongs to the field of preparation technology of partition frames, and in particular relates to a partition frame woven of composite materials and a preparation technology thereof. Background Art

[0002] Aircraft bulkheads are an important part of the aircraft structure. Their main function is to support and fix the aircraft's wings, fuselage, tail and other components, while bearing various loads of the aircraft during flight. In aircraft design, the design of the bulkhead must ensure sufficient strength and rigidity to ensure the safe operation of the aircraft. Aircraft bulkheads are usually made of metal (such as aluminum alloy, titanium alloy and stainless steel, etc.) or composite materials. The cross-section of a general aircraft bulkhead is Z-shaped or U-shaped. Aircraft bulkheads with a U-shaped cross-section also need to have a bulge on the bottom surface to meet engineering needs (see the attached figure of the instruction manual). Figure 7 ).

[0003] When preparing composite aircraft bulkheads, most of the methods currently used are prepreg unidirectional cloth laying + autoclave curing molding. However, since aircraft bulkheads are heterogeneous parts, it is difficult to control the fiber wrinkles, fiber gaps and fiber angles at the bends of the bulkheads using unidirectional cloth laying. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a composite material woven bulkhead and a preparation process thereof, so as to solve the problem in the prior art that fiber wrinkles, fiber gaps and fiber angles at the bending parts of the bulkhead are difficult to control.

[0005] To achieve the above-mentioned object and other related objects, the present invention provides a preparation process of a composite material woven partition frame, the preparation process comprising: S1: Splice the two halves of the core mold into a whole core mold with a rectangular cross section; S2: Clamp the entire core mold, and weave the fiber yarn on the entire core mold through a three-dimensional weaving machine to prepare a preform with a rectangular cross-section; S3: heating the preform and preliminarily curing the preform to prepare a preliminarily cured preform; S4: The plane where the side walls of the two halves of the core mold are in contact is the cutting plane. After the preform that is initially solidified is cooled, the preform that is initially solidified is divided into two U-shaped preforms along the cutting plane. S5: The U-shaped preform includes two vertical surfaces and one horizontal surface, and one of the vertical surfaces of the U-shaped preform is folded more than 90 degrees; S6: solidifying the folded U-shaped preform again to prepare a partition frame.

[0006] As an optional solution, in step S2, the braiding angle of the fiber yarn is 40-50°.

[0007] As an optional solution, in the step S2, the fiber yarn includes a reinforcing fiber yarn and a hot-melt yarn.

[0008] As an optional solution, the reinforcing fiber yarn includes carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, and aluminum oxide fiber.

[0009] As an optional solution, the heat-melt yarn includes heat-melt nylon yarn and heat-melt PET.

[0010] As an option, the melting point of the heat-fusible yarn is 80-90°.

[0011] As an optional solution, in step S3, when the preform is heated, the hot-melt yarn is melted and the reinforcing fiber yarn is bonded.

[0012] As an optional solution, in step S5, the two U-shaped preforms are respectively a first U-shaped preform and a second U-shaped preform, one of the vertical surfaces of the first U-shaped preform is folded by a°, and one of the vertical surfaces of the second U-shaped preform is folded by b°, where a+b=360; The folded vertical surface of the first U-shaped preform is attached to the folded vertical surface of the second U-shaped preform.

[0013] As an optional solution, in step S6, the folded U-shaped preform is cured again by infusing resin through RTM or vacuum infusion process.

[0014] The present invention also provides a composite material woven partition frame, which is obtained by adopting the above-mentioned preparation process.

[0015] As described above, the composite material woven partition frame and the preparation process thereof of the present invention have at least the following beneficial effects: 1. The present application uses a braiding machine to weave a preform, preliminarily solidify the preform, cut the preform, fold the preform, and solidify the preform again, so as to better control the fiber wrinkles, fiber gaps, and fiber angles at the bending of the bulkhead; 2. The preparation process of the bulkhead proposed in this application ensures the consistency of production, can reduce the influence of manual labor on the preparation of the bulkhead, and thus ensure the yield rate of the bulkhead preparation; 3. The hot-melt yarn provided in the present application is used to weave the hot-melt yarn and the reinforcing fiber yarn together in an interwoven manner through a three-dimensional braiding machine during weaving. When heated, the hot-melt yarn will melt into the preform, so it can be considered as a non-buckling single-layer braiding of the reinforcing fiber yarn, which greatly reduces the mechanical loss of the reinforcing fiber yarn; 4. Since the preform is woven layer by layer from the inside out, the hot-melt yarn provided in the present application can make the woven layers adhere to each other after being heated and melted, thereby ensuring the stability of the fiber structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram showing the structure of the preform of the present invention woven on the entire core mold; Figure 2 One embodiment of the two half core molds of the present invention is shown; Figure 3 Another embodiment of the two half core molds of the present invention is shown; Figure 4 Shown is a schematic structural diagram of the Z-type tooling of the present invention; Figure 5 Shown is a schematic structural diagram of a U-shaped tooling of the present invention; Figure 6 It is a schematic diagram showing the structure of the fiber yarn of the present invention being woven on the entire core mold; Figure 7 Shown is a schematic diagram of the structure of an existing U-shaped aircraft bulkhead.

[0017] In the figure: 11, half of the core mold; 12, the whole core mold; 21. Fiber yarn; 22. Reinforced fiber yarn; 23. Hot melt yarn; 31. preform; 32. first U-shaped preform; 33. second U-shaped preform; 41. Z-type tooling; 42. U-type tooling. DETAILED DESCRIPTION

[0018] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0019] See also Figures 1 to 6 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0020] The following embodiments are only for illustration purposes and can be combined with each other, and are not limited to the contents presented in the following single embodiments.

[0021] See also Figures 1 to 6 The present invention provides a preparation process of a composite material woven partition frame, the preparation process comprising: S1: splicing two halves of the core mold 11 into a whole core mold 12 with a rectangular cross section; The entire core mold 12 described here can be straight along the length direction (corresponding to a straight bulkhead) or curved (corresponding to a curved bulkhead); S2: Clamp the entire core mold 12, clamp the entire core mold 12 on the clamping hand, and drive the entire core mold 12 to move along the trajectory of its length through the robot slide, that is, when the entire core mold 12 is a straight line, the robot slide drives the entire core mold 12 to move in a straight line, and when the entire core mold 12 is an arc shape, the robot slide drives the entire core mold 12 to move in an arc shape; The fiber yarn 21 is woven on the entire core mold 12 by a three-dimensional weaving machine, thereby preparing a preform 31 with a rectangular cross-section; the three-dimensional weaving machine here is an inner ring weaving machine; In the step S2, the braiding angle of the fiber yarn 21 is 40-50°; In the step S2, the fiber yarn 21 includes a reinforcing fiber yarn 22 and a hot-melt yarn 23. The reinforcing fiber yarn 22 and the hot-melt yarn 23 are not limited here. The reinforcing fiber yarn 22 includes carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, alumina fiber, etc. The hot-melt yarn 23 includes hot-melt nylon yarn, hot-melt PET, etc. The melting point of the hot-melt yarn 23 is 80-90°.

[0022] S3: heating the preform 31 and preliminarily curing the preform 31, thereby preparing a preliminarily cured preform 31; In the step S3 , when the preform 31 is heated, the hot-melt yarn 23 is melted and the reinforcing fiber yarn 22 is bonded.

[0023] S4: The plane where the side walls of the two halves of the core mold 11 are in contact is the cutting plane. The cutting plane can be a vertical plane, that is, the cross-sections of the two halves of the core mold 11 are both rectangular. The cutting plane can also be an inclined plane with a certain angle to the vertical direction, that is, the cross-sections of the two halves of the core mold 11 are both trapezoidal. After the preliminarily solidified preform 31 is cooled, the preliminarily solidified preform 31 is divided into two U-shaped preforms along the cutting plane; In Example 1, the preparation of a partition frame with a Z-shaped cross section is taken as an example. S5: The U-shaped preform includes two vertical surfaces and one horizontal surface, and one of the vertical surfaces of the U-shaped preform is folded more than 90 degrees; S6: solidifying the folded U-shaped preform again to prepare a Z-shaped partition frame.

[0024] In the step S6, the folded U-shaped preform is cured again by infusing resin through RTM or vacuum infusion process.

[0025] In Example 2, the preparation of a bulkhead with a U-shaped cross section is taken as an example. In S5, the U-shaped preform includes two vertical surfaces and one horizontal surface, and one of the vertical surfaces of the U-shaped preform is folded more than 90 degrees; In order to facilitate the folding of the vertical surface of the U-shaped preform, a Z-shaped tool 41 may be used for folding; In the step S5, the two U-shaped preforms are respectively a first U-shaped preform 32 and a second U-shaped preform 33, one of the vertical surfaces of the first U-shaped preform 32 is folded a°, and one of the vertical surfaces of the second U-shaped preform 33 is folded b°, where a+b=360; After the preliminarily solidified preform 31 is cut but before being removed from the entire core mold 12, the vertical surface to be folded of the first U-shaped preform 32 and the vertical surface to be folded of the second U-shaped preform 33 are coplanar; The folded vertical surface of the first U-shaped preform 32 is attached to the folded vertical surface of the second U-shaped preform 33 , and the first U-shaped preform 32 and the second U-shaped preform 33 are fixed to each other by a U-shaped tool 42 .

[0026] S6: The folded U-shaped preform (i.e., the preform after the vertical surface of the folded first U-shaped preform 32 and the vertical surface of the folded second U-shaped preform 33 are attached to each other) is solidified again to prepare a U-shaped partition frame, wherein the vertical surface of the folded first U-shaped preform 32 and the vertical surface of the folded second U-shaped preform 33 become the protrusion of the U-shaped partition frame after solidification.

[0027] In the step S6, the folded U-shaped preform is cured again by infusing resin through RTM or vacuum infusion process.

[0028] A composite material woven partition frame is obtained by adopting the above-mentioned preparation process.

[0029] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A preparation process of a composite material woven partition frame, characterized in that: The preparation process comprises: S1: Splice the two halves of the core mold into a whole core mold with a rectangular cross section; S2: Clamp the entire core mold, and weave the fiber yarn on the entire core mold through a three-dimensional weaving machine to prepare a preform with a rectangular cross-section; S3: heating the preform and preliminarily curing the preform to prepare a preliminarily cured preform; S4: The plane where the side walls of the two halves of the core mold are in contact is the cutting plane. After the preform that is initially solidified is cooled, the preform that is initially solidified is divided into two U-shaped preforms along the cutting plane. S5: The U-shaped preform includes two vertical surfaces and one horizontal surface, and one of the vertical surfaces of the U-shaped preform is folded more than 90 degrees; S6: solidifying the folded U-shaped preform again to prepare a partition frame.

2. The process for preparing a composite material woven partition frame according to claim 1, characterized in that: In step S2, the braiding angle of the fiber yarn is 40-50°.

3. The preparation process of a composite material woven partition frame according to claim 1, characterized in that: In the step S2, the fiber yarn includes a reinforcing fiber yarn and a hot-melt yarn.

4. The process for preparing a composite material woven partition frame according to claim 3, characterized in that: The reinforcing fiber yarn includes carbon fiber, glass fiber, aramid fiber, silicon carbide fiber and alumina fiber.

5. The process for preparing a composite material woven partition frame according to claim 3, characterized in that: The hot-melt yarn includes hot-melt nylon yarn and hot-melt PET.

6. The process for preparing a composite material woven partition frame according to claim 3, characterized in that: The melting point of the hot-melt yarn is 80-90°.

7. The process for preparing a composite material woven partition frame according to claim 3, characterized in that: In the step S3, when the preform is heated, the hot-melt yarn is melted and the reinforcing fiber yarn is bonded.

8. The process for preparing a composite material woven partition frame according to claim 3, characterized in that: In the step S5, the two U-shaped preforms are respectively a first U-shaped preform and a second U-shaped preform, one of the vertical surfaces of the first U-shaped preform is folded by a degree, and one of the vertical surfaces of the second U-shaped preform is folded by b degree, where a+b=360; The folded vertical surface of the first U-shaped preform is attached to the folded vertical surface of the second U-shaped preform.

9. The process for preparing a composite material woven partition frame according to claim 1, characterized in that: In the step S6, the folded U-shaped preform is cured again by infusing resin through RTM or vacuum infusion process.

10. A composite material woven partition frame, characterized in that: The method is obtained by using the preparation process described in any one of claims 1 to 9.

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