A cavity structural member unit preform and preparation method thereof

Abstract

The present invention describes a regular triangular pyramid hollow structural component unit preform and a preparation method thereof. The expanded view of the preform is splicable, which reduces the loss of carbon fiber cloth. Moreover, the spliced ​​triangular pyramid faces have continuous fibers, and the prepared regular triangular pyramid preform has higher stability. The regular triangular pyramids are connected by seams. After being spliced ​​into the required structural component shape, they are wrapped with a complete fiber cloth for further connection.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and relates to a preform of a cavity structural member unit and a preparation method thereof. Technical Background

[0002] Composite materials are the main materials for the main structural members of aerospace satellites. In the preparation process of the main structural members of aerospace satellites, lightweight and reliability are quite important basic conditions. In the preparation process of traditional large structural preforms, due to the limitations of materials and processes, large-sized components are often split into multiple small and medium-sized structural preforms, and finally the small and medium-sized structural preforms are combined for preparation.

[0003] However, the integrated structure of aerospace structural members is an inevitable trend in the development of aerospace materials. In the design process of aerospace components with complex structures, the integrated design itself has relatively high design requirements and requires corresponding tooling and molds, and the overall cost is very high. Summary of the Invention

[0004] To solve the above problems, the present invention describes a preform of a cavity structural member unit and a preparation method thereof, characterized in that:

[0005] S1. Cut the fiber cloth into the shape of 8 connected regular triangular fiber cloths, with the number of n pieces, where n is a positive integer;

[0006] S2. Prepare a regular triangular pyramid core mold;

[0007] S3. Wrap the fiber cloth around the core mold;

[0008] S4. Sew with a sewing needle;

[0009] S5. Piece together and sew;

[0010] S6. Wrap and sew.

[0011] Preferably, cut the fiber cloth into a "丆"-shaped fiber cloth. The "one" of the "丆" is formed by arranging four regular triangles in a straight line, the "丿" of the "丆" is formed by arranging four regular triangles in a straight line, and one end of the "丿" is connected to the second or third regular triangle of the "one".

[0012] Furthermore, the "丆"-shaped fiber cloth can be pieced together into a complete fiber cloth, reducing the waste of the surplus of carbon fiber. The method of cutting the "丆"-shaped fiber cloth is as Figure 2 and Figure 3 shown;

[0013] Furthermore, stack the "丆"-shaped fiber cloths to a thickness of 1 mm - 8 mm.

[0014] Preferably, prepare a regular triangular pyramid core mold;

[0015] Furthermore, the surface of the core mold has card slots or the core mold can be punctured by a suture needle.

[0016] Preferably, equilateral triangle patterns are drawn on the "丆"-shaped fiber cloth, and the "丆"-shaped fiber cloth is wrapped around the regular triangular pyramid core mold along the patterns, with each fold being an inward fold;

[0017] Furthermore, after folding, each of the four faces of the regular triangular pyramid is twice the thickness of the fiber cloth;

[0018] Furthermore, there are continuous fibers connecting adjacent faces of the regular triangular pyramid.

[0019] Preferably, the wrapped fiber cloth is sutured, and the suture method is a running stitch, with the density of the suture needle being 5mmX5mm to 40mmX40mm.

[0020] Preferably, the mth "丆"-shaped fiber cloth laminate is prepared, where m≥2 and m is a positive integer. The A face is the second equilateral triangle from top to bottom of the "丿", and the a face is the first equilateral triangle from left to right of the "一"; the "丆"-shaped laminated fiber cloth is folded to a state where the A face coincides with the a face, and the A face and the a face are adhered to one face of the prefabricated regular triangular pyramid that has been prepared. After adhesion, it is sutured, and the suture method is a running stitch, with the density of the suture needle being 5mmX5mm to 40mmX40mm; the mth regular triangular pyramid core mold is placed, and the mth regular triangular pyramid core mold is coated and sutured, and the suture method is a running stitch, with the density of the suture needle being 5mmX5mm to 40mmX40mm.

[0021] Furthermore, the regular triangular pyramid core mold is placed;

[0022] Furthermore; the regular triangular pyramid core mold is coated.

[0023] Preferably, when the number of triangular pyramids reaches 4, they are spliced into a regular triangular pyramid 4 times as large, and the "丆"-shaped fiber cloth with twice the side length is cut;

[0024] Furthermore, the "丆"-shaped fiber cloth laminate with twice the side length is laminated to 1mm - 8mm;

[0025] Furthermore, the "丆"-shaped fiber cloth laminate with twice the side length is coated on a regular triangular pyramid 5 times as large to achieve the effect of fiber continuity.

[0026] Furthermore, this technology is applicable to regular triangular pyramids 5 times as large, 14 times as large, and 34 times as large.

[0027] Furthermore, the shape of the prefabricated body prepared by this technology can be adjusted according to the main structure. Description of the Drawings

[0028] For better understanding, the present invention is described in conjunction with the accompanying drawings and embodiments;

[0029] Figure 1 This is a structural diagram of the unit structure preform of the present invention;

[0030] Figure 2 The solid lines are the fiber cloth cutting methods, and the dotted lines are the folding lines;

[0031] Figure 3 Cut the cut shape for the fiber cloth;

[0032] Figure 4 To mark the 8 folded surfaces of the cut fiber cloth;

[0033] Figure 5 It is a schematic diagram of the seam-jointing method;

[0034] Figure 6 Schematic diagram of the method for splicing and stitching adjacent prefabricated bodies. Specific implementation plan

[0035] Triangular structures are very stable. This invention utilizes a regular triangular pyramid preform as the basic unit for aerospace component preforms, achieving lightweight construction. To facilitate understanding of this technical solution, the regular triangular pyramid preform can be thought of as a brick, and the aerospace component preform as a house. The following describes the specific preparation method and key technical points.

[0036] Prepare a piece of T300-3K rectangular carbon fiber cloth with a side width of 1000mm. Figure 2 Draw a solid line, the solid line part is the cutting line, and the dotted line part is the folding line. Figure 2 The side length of the drawn single triangle is 120 mm.

[0037] The carbon fiber cloth is disassembled into multiple pieces of single-structure cloth. The thickness of the single-fiber cloth is 0.3mm. It is necessary to stack more than 7 layers of single-structure cloth with a thickness of more than 2mm. The length of the triangle of the bottom surface of the stacked single-structure cloth is 120mm. After that, the length of the triangle decreases by 2mm for every 3 layers stacked.

[0038] In order to facilitate the folding of the laminated fiber cloth, the laminated fiber cloth is simply sewn and then locked. Prepare a regular triangular pyramid core mold with a side length of 118mm, use the laminated cloth at the short triangle side as the inner cloth, and the laminated cloth at the 120mm side triangle as the outer cloth, and fold the laminated cloth along the dotted line to the inner side around the regular triangular pyramid. Figure 2 In the cut structure, the four faces of the wrapped regular triangular pyramid after unidirectional folding are adjacent and connected by continuous fibers, making the structure more stable. Figure 4As shown in the figure, after the regular triangular pyramid is folded, the A surface and the a surface are coincident, the B surface and the b surface are coincident, the E surface and the e surface are coincident, and the D surface and the d surface are coincident. The coincident surfaces are sutured and connected after the regular triangular pyramid is prepared, so the coincident surfaces share the continuous fibers with the adjacent surfaces. The regular triangular pyramid prepared by this folding method is as follows. Figure 4 As shown, surface A (a) and surface B (b) achieve continuity through surface a and surface B; surface A (a) and surface E (e) achieve continuity through surface A and surface E; surface A (a) and surface D (d) achieve continuity through surface A and surface D; surface B (b) and surface E (e) achieve continuity through surface B and surface E; surface B (b) and surface D (d) achieve continuity through surface B and surface d; surface E (e) and surface D (d) achieve continuity through surface e and surface d. Under this technology, the surfaces of the regular triangular pyramid prefabricated body are continuous and the structure is firm.

[0039] After the regular triangular pyramid is folded, it is sutured. The suture method is the adjacent suture. The adjacent suture fiber method is as follows: Figure 5 As shown, a special needle is used to bring the carbon fiber into the regular triangular pyramid surface and sew it in a triangular dot array, with the distance between points being 5mm.

[0040] After completing the preparation of a regular triangular pyramid preform, prepare a second regular triangular pyramid preform. Figure 6 Fold in this manner, with surface A (a) overlapping first. After overlapping, surface A (a) is aligned with any surface of the first preform and then stitched. The stitching method is a contiguous stitching, with a triangular dot pattern and a distance of 5 mm between points. Place the core mold in the second preform, fold inward around the core mold, and stitch.

[0041] After adding n preforms according to the above method, they are built into the required shape, and the edges are filled with special-shaped preforms to build the final shape, and then covered with a whole piece of fiber cloth to keep all small preform components tightly combined.

Claims

1. A prefabricated unit of a cavity structure member and its preparation method, characterized in that: S1. Cut the fiber cloth into 8 conjoined regular triangle fiber cloth shapes, with the number of n pieces, where n is a positive integer; the fiber cloth is cut into a "丆"-shaped fiber cloth; 8 triangular patterns are drawn on the "丆"-shaped fiber cloth; the "一" of the "丆" is formed by arranging four regular triangles in a straight line; the "丿" of the "丆" is formed by arranging four regular triangles in a straight line; one end of the "丿" is connected to the second or third regular triangle of the "一". S2. Prepare a regular triangular pyramid core mold: The core mold is a regular triangular pyramid; there are card slots on the surface of the core mold or the core mold can be punctured by a sewing needle. S3. Wrap the core mold with the fiber cloth: The "丆"-shaped fiber cloth is folded along the pattern to wrap the regular triangular pyramid core mold, and each fold is inward. S4. Sew with a sewing needle: Sew the wrapped regular triangular pyramid prefabricated body, and the sewing method is temporary sewing, and the sewing needle density is between 5mmX5mm and 40mmX40mm. S5. Piece together and sew: Prepare the mth "丆"-shaped fiber cloth laminate, where m≥2 and m is a positive integer, the A surface is the second regular triangle from top to bottom of the "丿", and the a surface is the first regular triangle from left to right of the "一"; fold the "丆"-shaped laminated fiber cloth until the A surface and the a surface coincide, and the A surface and the a surface are bonded to one surface of the prefabricated regular triangular pyramid that has been prepared, and then sew after bonding. The sewing method is temporary sewing, and the sewing needle density is between 5mmX5mm and 40mmX40mm; put the mth regular triangular pyramid core mold in, cover and sew the mth regular triangular pyramid core mold, and the sewing method is temporary sewing, and the sewing needle density is between 5mmX5mm and 40mmX40mm. S6. Cover and sew: Combine the regular triangular pyramids into the required component shape, and use a complete fiber cloth for overall covering and sewing. The sewing method is temporary sewing, and the sewing needle density is between 5mmX5mm and 40mmX40mm.

2. The hollow structural member unit preform and the preparation method thereof according to claim 1, characterized in that: The "丆"-shaped fiber cloth can be spliced into a complete fiber cloth to reduce the waste of carbon fiber surplus.

3. The hollow structural member unit preform and the preparation method thereof according to claim 1, characterized in that: All four faces of the regular triangular pyramid are wrapped with a thickness of 2 times the fiber cloth.

4. The hollow structural member unit preform and the preparation method thereof according to claim 1, characterized in that: There are continuous fibers between adjacent faces of the regular triangular pyramid prefabricated body.

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