Integral forming method of a composite hollow ring frame with c-shaped flange

Abstract

The application discloses a kind of whole forming methods of composite hollow ring frame with C-shaped flanging, the structure of hollow ring frame with C-shaped flanging is split into annular skin assembly, left side C-shaped reinforcing rib assembly, right side C-shaped reinforcing rib assembly three parts, after assembly laying, it is matched and assembled integral solidification again.To meet the above process design scheme requirement, forming tool is also designed in subassembly, including annular skin laying tool, left side C-shaped reinforcing rib laying tool, right side C-shaped reinforcing rib laying tool and auxiliary matching baffle.The application can guarantee the forming quality of composite hollow ring frame structure with C-shaped flanging, and the C-shaped flanging on both sides can also play the role of reinforcing rib, significantly improve the integrated effect of part weight reduction and compression resistance, with good practical value.

Description

Technical Field

[0001] This invention relates to a method for integral molding of a hollow composite ring frame with C-shaped flanges. Background Technology

[0002] With the development of marine resource exploration and development, deep-sea scientific research, and the upgrading of underwater weaponry, higher demands are being placed on deep-sea submersible surveying equipment, especially in terms of weight reduction and underwater pressure resistance. This requires the shell structure of deep-sea pressure-bearing equipment to meet requirements such as low specific gravity, high strength, high modulus, deformation resistance, and fatigue resistance. However, long cylindrical shell structures are prone to compressive buckling instability due to the increased external pressure load caused by increased surveying depth, leading to shell buckling failure, resulting in undulating shapes or even flattening. To avoid compressive buckling instability, a common measure is to arrange I-shaped or L-shaped reinforcing ribs on the inner side of the solid cylindrical structure to enhance compressive stability. However, this method of solid cylindrical reinforcement can easily lead to problems such as increased weight and material costs.

[0003] Therefore, a hollow ring frame structure with C-shaped flanges was designed and developed. The C-shaped flanges on both sides are locally thickened to act as reinforcing ribs, and the circumferential skin can increase the overall thickness of the cylinder section. At the same time, the C-shaped cavity of the ring frame increases the structural fill ratio and reduces the weight of the cylinder section, ultimately achieving the effect of integrated weight reduction and compression resistance. However, because the hollow ring frame has a special structure with C-shaped flanges on both sides, there is a risk of difficulty in demolding when using a male mold tooling for integrated molding. When using a female mold tooling for integrated molding, there are problems such as the flanges not being able to be folded smoothly, requiring manual cutting and filling of material gaps, which are inconvenient and inefficient.

[0004] Therefore, how to form a hollow ring frame structure of composite materials with C-shaped flanges, and how to solve the risks of demolding and ensure smooth folding are still urgent problems to be solved. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for integrally molding a hollow composite frame with C-shaped flanges. The structure of the hollow frame with C-shaped flanges is divided into three parts: an annular skin, a left-side C-shaped reinforcing rib, and a right-side C-shaped reinforcing rib. The localized thickening of the C-shaped flanges on both sides acts as reinforcing ribs. The circumferential skin increases the overall thickness of the cylindrical section, while the C-shaped cavity of the frame increases the structural fill ratio, reducing the weight of the cylindrical section, ultimately achieving a combined effect of weight reduction and compressive strength. This invention mainly achieves the manufacturing of the hollow composite frame structure with C-shaped flanges through structural design and a co-curing molding process. Compared with traditional methods, the use of a component-based co-curing process and group-layout of components solves the problem of difficult integral molding of the male mold, improving production efficiency, saving material costs, and greatly ensuring the structural strength and compressive strength of the product. The specific technical solution is as follows:

[0006] S1. Mold design: Based on the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame is divided into a ring skin assembly, a left C-shaped reinforcing rib assembly, and a right C-shaped reinforcing rib assembly.

[0007] S2, Laying Design: Based on the structural form of each component designed in step S1, design and prepare the corresponding laying fixtures, and design the layup of each component, and design different layup angles and proportions according to strength requirements.

[0008] S3. Mold parting and laying: According to the requirements, lay the prepreg sheets of each component onto the corresponding mold parting and laying fixture;

[0009] S4. Pre-molding: After the pre-molding is completed, the prepreg sheets of each component, together with their respective pre-molding installation fixtures, are sent into the autoclave for hot compaction to obtain the annular skin component, the left C-shaped reinforcing rib component, and the right C-shaped reinforcing rib component.

[0010] S5. Co-curing: After the pre-forming by mold separation, the left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly are demolded, and then matched and assembled with the annular skin assembly. Twisted wires are filled at the R-corner, and after encapsulation, they are sent into the autoclave for hot-press co-curing.

[0011] S6. Demolding and molding: After co-curing, remove the installation fixtures for each component to obtain a hollow composite material ring frame with C-shaped flanges.

[0012] As a preferred technical solution, the left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly in step S are annular reinforcing rib structures with a C-shaped cross-section. Their outer diameter is equal to the inner diameter of the annular skin assembly, which is used to realize that the left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly are respectively fitted into the annular holes at both ends of the annular skin assembly.

[0013] As a preferred technical solution, the laying fixture in step S includes a forming fixture for the annular skin assembly, a forming fixture for the left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly, and a sliding base for supporting the forming fixture of the annular skin assembly.

[0014] The forming fixture for the annular skin assembly is a metal female mold fixture, which includes an annular metal paving body, two inner flanged metal baffles and two outer limiting metal baffles. The two inner flanged metal baffles are respectively installed inside the annular metal paving body near the two ends, and the two outer limiting metal baffles are respectively installed at both ends of the annular metal paving body to ensure that the inner flanges of the C-shaped reinforcing ribs assembled at both ends of the annular metal paving body are formed.

[0015] The ring-shaped metal paving body includes mold A, mold B and mold C. The connection between mold A, mold B and mold C is provided with connecting ears for assembly between the three. During assembly, mold A is located on the upper part of the sliding base.

[0016] The molding fixtures for both the left and right C-shaped reinforcing rib components are male mold fixtures. The male mold fixture is a substitute wooden mold fixture. The substitute wooden mold fixture includes a limiting base, and an annular support seat is provided on the limiting base. The annular support seat can match and fit with the groove of the C-shaped reinforcing rib component to realize the C-shaped reinforcing rib component being laid and formed on the male mold fixture.

[0017] As a preferred technical solution, the sliding base includes an arc-shaped support base, and a sliding roller is embedded along the arc-shaped surface trajectory of the arc-shaped support base. Each sliding roller is provided with a slider. Limiting baffles are provided at both ends of the support base. The metal female mold fixture is fitted into the arc-shaped surface of the arc-shaped support base, and the bottom of the metal female mold fixture is in contact with the slider.

[0018] The metal female mold fixture on the sliding base can slide along the track of the sliding groove to the limiting baffle, and roll the annular metal laying body on the sliding base at a certain angle to realize the rolling laying and scraping of the annular skin assembly in the metal female mold fixture.

[0019] As a preferred technical solution, the layup design in step S is as follows:

[0020] The ply design of the annular skin assembly is as follows: the annular skin assembly is divided into several ply layers according to its thickness, and the ply layers are stacked together.

[0021] The layup design of the left and right C-shaped reinforcing rib assemblies is as follows:

[0022] S-: The left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly are divided into a first thickness zone, a second thickness zone, and a third thickness zone according to their thickness; the ply thickness of each thickness zone is second thickness zone > first thickness zone > third thickness zone;

[0023] S-: According to the thickness partitioning in step S-, the plies of the left C-type reinforcing rib assembly and the right C-type reinforcing rib assembly are sequentially divided into I-type plies, L-type plies, and C-type plies; the I-type plies are laid in the second thickness region, the L-type plies are laid in the first thickness region and the second thickness region, and the C-type plies are laid in the first thickness region, the second thickness region, and the third thickness region.

[0024] The C-type, L-type, and I-type plies are laid alternately and in a ply ratio of °: °: °=:: to achieve symmetrical plies along the middle layer.

[0025] As a preferred technical solution, step S, the mold separation and laying process, is as follows:

[0026] The annular prepreg sheet of the annular skin assembly is divided into multiple prepreg sheet parts, which are sequentially laid onto the metal female mold fixture, and can be connected to form a complete annular prepreg sheet within the metal female mold fixture.

[0027] As a preferred technical solution, the parameters for hot compaction in step S4 are: temperature 50℃, pressure 0.6Mpa, and heat and pressure holding time 30min.

[0028] As a preferred technical solution, the matching assembly in step S5 specifically involves: demolding the pre-formed left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly from the male mold tooling, but not demolding the pre-formed annular skin assembly from the metal female mold tooling, and then demolding the left C-shaped reinforcing rib assembly and the right C-shaped reinforcing rib assembly into the ply ends of the undemolded annular skin assembly.

[0029] As a preferred technical solution, the co-curing parameters in step S5 are: temperature 180±5℃, curing pressure 0.4~0.6Mpa, holding time 150~180min, and heating / cooling rate 1~3% / min.

[0030] As a preferred technical solution, the demolding process in step S6 specifically involves removing the metal female mold tooling after co-curing in step S5, and taking out each mold body in sequence according to the order of first removing the mold parts B and C on both sides of the upper end, and then removing the mold part A located on the sliding base.

[0031] The beneficial effects of this invention are as follows:

[0032] (1) Compared with the traditional solid cylinder section, the present invention has a composite hollow ring frame structure with C-shaped flanges. The C-shaped flanges on both sides are locally thickened to act as reinforcing ribs. The circumferential skin can increase the overall thickness of the cylinder section. At the same time, the C-shaped cavity of the ring frame increases the structural duty cycle and reduces the weight of the cylinder section, ultimately achieving the effect of weight reduction and pressure resistance integration.

[0033] (2) This invention divides the structure of the hollow ring frame with C-shaped flange into three parts: annular skin, left C-shaped reinforcing rib, and right C-shaped reinforcing rib. It adopts a component-based laying and co-curing process, which solves the problem of difficult one-piece molding of the hollow ring frame male mold. The laying process of the two components can be carried out simultaneously, which simplifies the laying process, improves production efficiency, saves material costs, and greatly ensures the structural strength and compressive strength of the product. Under the premise of ensuring the quality of the parts, the production cost is greatly reduced. Attached Figure Description

[0034] Figure 1 A hollow ring frame structure made of composite material with C-shaped flanges is described as an integral molding method for the hollow ring frame.

[0035] Figure 2 for Figure 1 Disassembly diagram;

[0036] Figure 3 Schematic diagram of the matching assembly of the C-type reinforcing rib assembly and the annular skin assembly.

[0037] Figure 4 A schematic diagram of the molding tooling for an integral molding method of a hollow ring frame made of composite material with C-shaped flanges;

[0038] Figure 5 Schematic diagram of the disassembly of the molding tooling

[0039] Figure 6 Schematic diagram of metal female mold tooling disassembly

[0040] Figure 7 Schematic diagram of the overlapping joint of the circular paving body

[0041] Figure 8 for Figure 4 Disassembly diagram;

[0042] Figure 9 Schematic diagram of the sliding base structure

[0043] Figure 10 A schematic diagram of C-shaped reinforcing rib laying in an integral molding method for a hollow ring frame of composite material with C-shaped flanges;

[0044] Figure 11 A schematic diagram of the application of a ring-shaped skin assembly for an integral molding method of a hollow ring frame made of composite material with C-shaped flanges;

[0045] Figure 12 Diagram of positive mold tooling installation.

[0046] The meanings of the markings in the diagram are as follows: 1. Hollow ring frame of composite material with C-shaped flange; 2. Annular skin assembly; 3. Left C-shaped reinforcing rib; 4. Right C-shaped reinforcing rib; 5. Metal female mold fixture; 501. Annular metal paving body; A. Mold parting A; B. Mold parting B; C. Mold parting C; 502. Outer limiting metal baffle; 503. Inner flanged metal baffle; 6. Sliding base; 601. Arc-shaped support seat; 602. Sliding roller; 603. Slider; 604. Limiting baffle; 7. Male mold fixture; 701. Substitute wooden mold fixture; 7011. Limiting base; 7012. Annular support seat; 8. I-shaped reinforcing layer; 9. L-shaped reinforcing layer; 10. C-shaped reinforcing layer; 11. Release membrane; 12. Surface breathable material; 13. Vacuum bag; 14. Demolding material. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments.

[0048] Example 1

[0049] This embodiment describes a method for integral molding of a hollow ring frame made of composite material with C-shaped flanges. The steps are as follows:

[0050] S1. Mold design: Based on the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame 1 with C-shaped flange is divided into a ring skin assembly 2, a left C-shaped reinforcing rib assembly 3, and a right C-shaped reinforcing rib assembly 4.

[0051] S2, Laying Design: Based on the structural form of each component designed in step S1, design and prepare the corresponding laying fixtures, and design the layup of each component, and design different layup angles and proportions according to strength requirements.

[0052] S3. Mold parting and laying: According to the requirements, lay the prepreg sheets of each component onto the corresponding mold parting and laying fixture;

[0053] S4. Pre-molding: After the pre-molding is completed, the prepreg sheets of each component, together with their respective pre-molding installation fixtures, are sent into the autoclave for hot compaction to obtain the annular skin component 2, the left C-shaped reinforcing rib component 3, and the right C-shaped reinforcing rib component 4.

[0054] S5. Co-curing: After the pre-forming by mold separation, the left C-shaped reinforcing rib component 3 and the right C-shaped reinforcing rib component 4 are demolded, and then matched and assembled with the annular skin component 2. Twisted wires are filled at the R corners, and after encapsulation, they are sent into the autoclave for hot-press co-curing.

[0055] S6. Demolding and molding: After co-curing, the installation fixtures for each component are removed to obtain a hollow composite material ring frame 1 with C-shaped flanges.

[0056] Reference Figures 1 to 12 In the integral molding method of the hollow ring frame with C-shaped flange of composite material described in this embodiment, the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 in step S1 are annular reinforcing rib structures with a C-shaped cross section. Their outer diameter is equal to the inner diameter of the annular skin assembly 2, which is used to realize that the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 are respectively sleeved inside the annular holes at both ends of the annular skin assembly 2.

[0057] In this embodiment, the laying fixture in step S2 includes a forming fixture for the annular skin assembly 2, forming fixtures for the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4, and a sliding base 6 for supporting the forming fixture of the annular skin assembly 2; the forming fixture for the annular skin assembly 2 is a metal female mold fixture 5, which includes an annular metal laying body 501, two inner flange metal baffles 503 and two outer limiting metal baffles 502, and the two inner flange metal baffles 503 are respectively installed Inside the annular metal paving body 501, near the two ends, two external limiting metal baffles 502 are respectively installed at both ends of the annular metal paving body 501 to ensure that the inner side of the C-shaped reinforcing ribs assembled at both ends of the annular metal paving body 501 is flanged; wherein the annular metal paving body 501 includes a mold A, a mold B, and a mold C, and the connection between the mold A, mold B, and mold C is provided with connecting ears for assembly between the three; during assembly, the mold A is located on the upper part of the sliding base 6;

[0058] The molding fixtures for both the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 are male mold fixtures 7. The male mold fixture 7 is a wooden mold fixture 701. The wooden mold fixture 701 includes a limiting base 7011. The limiting base 7011 is provided with an annular support seat 7012. The annular support seat 7012 can match and fit with the groove of the C-shaped reinforcing rib assembly to realize the C-shaped reinforcing rib assembly being laid and formed on the male mold fixture 7.

[0059] In this embodiment, the sliding base 6 includes an arc-shaped support 601, with a sliding roller 602 embedded along the arc-shaped surface trajectory of the arc-shaped support 601. Each sliding roller 602 has a slider 603 inside. Limiting baffles (604) are provided at both ends of the support 601. The metal female mold fixture 5 is fitted onto the arc-shaped surface of the arc-shaped support 601. The bottom of the metal female mold fixture 5 is in contact with the slider 603. The metal female mold fixture 5 on the sliding base 6 can slide along the track of the sliding roller 602 to the limiting baffle (604), rolling the annular metal laying body 501 on the sliding base 6 at a certain angle, thereby realizing the rolling laying and scraping of the annular skin assembly 2 within the metal female mold fixture 5.

[0060] The integral molding method for the hollow ring frame with C-shaped flange composite material described in this embodiment includes the following layup design in step S2:

[0061] The ply design of the annular skin assembly 2 is as follows: the annular skin assembly 2 is divided into several ply layers according to its thickness, and the ply layers are stacked together.

[0062] The layup design of the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 is as follows:

[0063] S2-1: The left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 are divided into a first thickness zone, a second thickness zone, and a third thickness zone according to their thickness; the layup thickness of each thickness zone is second thickness zone > first thickness zone > third thickness zone;

[0064] S2-2: Based on the thickness partitioning in step S2-1, the plies of the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 are sequentially divided into I-shaped plies 8, L-shaped plies 9, and C-shaped plies 10, respectively; the I-shaped plies 8 are laid in the second thickness region, the L-shaped plies 9 are laid in the first thickness region and the second thickness region, and the C-shaped plies 10 are laid in the first thickness region, the second thickness region, and the third thickness region;

[0065] The C-type layup 10, L-type layup 9 and I-type layup 8 are laid alternately and in a layup ratio of 0°:45°:90°=8:4:6 to achieve symmetrical layup along the middle layer.

[0066] The integral molding method for the hollow ring frame with C-shaped flange composite material described in this embodiment includes the following step S3: mold splitting and laying:

[0067] The annular prepreg sheet of the annular skin assembly is divided into multiple prepreg sheet parts, which are sequentially laid onto the metal female mold fixture 5 and can be connected to form a complete annular prepreg sheet within the metal female mold fixture 5.

[0068] The integral molding method of the hollow ring frame with C-shaped flange composite material described in this embodiment has the following parameters for hot compaction in step S4: temperature 50℃, pressure 0.6 MPa, and heat and pressure holding time 30 min.

[0069] The integral molding method of the hollow ring frame with C-shaped flange composite material described in this embodiment, the matching assembly in step S5 specifically involves: demolding the pre-formed left C-shaped reinforcing rib assembly 3 and right C-shaped reinforcing rib assembly 4 from the male mold fixture 7, but not demolding the pre-formed annular skin assembly 2 from the metal female mold fixture 5; and then attaching the demolded left C-shaped reinforcing rib assembly 3 and right C-shaped reinforcing rib assembly 4 to the inside of the two ends of the ply of the undemolded annular skin assembly 2.

[0070] The integral molding method of the hollow ring frame with C-shaped flange composite material described in this embodiment has the following co-curing parameters in step S5: temperature 180±5℃, curing pressure 0.4~0.6Mpa, holding time 150~180min, and heating / cooling rate 1~3% / min.

[0071] The integral molding method of the hollow ring frame with C-shaped flange of composite material described in this embodiment, the demolding molding in step S6 specifically means: when removing the metal female mold tooling 5 after co-curing in step S5, the mold parts B and C on both sides of the upper end are removed first according to the demolding angle, and then the mold A located on the sliding base 6 is removed in sequence to take out each mold part.

[0072] The following section uses a C-shaped flanged hollow ring frame structure as an example to detail the specific steps of the integral molding method for the composite hollow ring frame with C-shaped flanges described in this embodiment:

[0073] S1. Mold design: Based on the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame is divided into the ring skin component 2, the left C-shaped reinforcing rib component 3, and the right C-shaped reinforcing rib component 4.

[0074] S2, Laying Design: Based on the circumferential length of the annular skin component 2 and the thickness of the left and right C-shaped reinforcing rib components 4, Fibersim software is used to design different configuration sheet materials and design different layup angle ratios according to strength requirements. At the same time, prepare the metal female mold tooling 5 for laying the annular skin component 2 and the laying tooling 7 for the left and right C-shaped reinforcing rib components 4, and perform cleaning and demolding material 14 brushing.

[0075] S3. Mold Splitting and Laying: Lay the annular skin assembly 2 on the metal female mold fixture 5; lay the reinforcing layers 8, 9, and 10 of the left and right C-shaped reinforcing rib assemblies 4 on the male mold fixture 7. The laying of both is carried out simultaneously to improve efficiency. The reinforcing layers mainly include three configurations: C, I, and L, and the three configurations are laid alternately.

[0076] S4. Mold Pre-forming: First, perform vacuum pre-compression sealing and leak testing on the molds laid in step S3. After passing the leak test, use auxiliary materials such as isolation film 11, surface breathable material 12, and vacuum bag 13 to seal each mold and apply vacuum pre-compression. Send the sealed parts and tooling into the autoclave. Set the autoclave parameters as follows: temperature 50℃, pressure 0.6Mpa, and heat preservation and pressure holding time 30min. Hot-press the sealed components in the autoclave. After removing them from the autoclave, you can obtain the annular skin assembly 2, the left C-shaped reinforcing rib assembly 3, and the right C-shaped reinforcing rib assembly 4.

[0077] S5. Co-curing: After pre-forming by mold separation, demold the left C-shaped reinforcing rib assembly 3 and the right C-shaped reinforcing rib assembly 4 from the male mold fixture 7, while keeping the annular skin assembly 2 intact. Match the obtained left C-shaped reinforcing rib assembly 3 and right C-shaped reinforcing rib assembly 4 to the inside of the annular layup ends of the annular skin assembly 2. Check the triangular area between the reinforcing rib assembly and the annular skin assembly 2 and fill it with an appropriate amount of carbon twisted wire to ensure a perfect fit without gaps. Then, pre-compact the parts and seal them with the surface breathable material 12. Then, install and combine the outer limiting metal baffles and inner flange metal baffles 503 on both sides of the metal female mold fixture 5. After completion, send it into the autoclave, set the parameters of the autoclave, and perform hot-press co-curing. Then, match and assemble it with the annular skin assembly 2, fill the R-corner with twisted wire, seal it, and send it into the autoclave for hot-press co-curing.

[0078] S6, Demolding and molding: Remove the metal female mold tooling 5 after co-curing in step S5, and remove the molds B and C on both sides of the upper end according to the demolding angle, and then remove the mold A located on the sliding base (6) in sequence. Remove the remaining paving to obtain the C-shaped flanged composite hollow ring frame.

[0079] In summary, this invention provides theoretical guidance for practice. Compared to traditional solid cylindrical sections, this design, featuring C-shaped reinforcing layers on both sides of the adhesive bonding area, achieves both weight reduction and ensures compressive strength. The invention employs a modular approach, with the main layer and reinforcing layers installed in separate components. The installation of both components can be performed simultaneously, simplifying the process, improving production efficiency, and significantly reducing production costs while maintaining component quality. It also avoids damage to components caused by post-processing. The three different configurations of the reinforcing layers, applied alternately at different angles, greatly enhance the product's structural strength and compressive strength. This invention effectively solves technical problems in a simple way, demonstrating ingenious design and significant practical value.

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalent elements of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0081] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for integral molding of a hollow ring frame made of composite material with C-shaped flanges, characterized in that: Includes the following steps: S1. Mold design: Based on the structural form of the composite hollow ring frame (1) with C-shaped flange, it is divided into an annular skin assembly (2), a left C-shaped reinforcing rib assembly (3), and a right C-shaped reinforcing rib assembly (4). S2. Laying Design: Based on the structural form of each component designed in step S1, design and prepare the corresponding laying fixtures. Simultaneously, design the layup of each component, and design different layup angles and proportions according to strength requirements; details are as follows: The ply design of the annular skin assembly (2) is as follows: the annular skin assembly (2) is divided into several ply layers according to its thickness, and the ply layers are stacked together. The layup design of the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) is as follows: S2-1: The left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) are divided into a first thickness zone, a second thickness zone and a third thickness zone according to their thickness; the ply thickness of each thickness zone is second thickness zone > first thickness zone > third thickness zone; S2-2: According to the thickness partitioning in step S2-1, the plies of the left C-type reinforcing rib assembly (3) and the right C-type reinforcing rib assembly (4) are sequentially divided into I-type plies (8), L-type plies (9), and C-type plies (10); the I-type plies (8) are laid in the second thickness region, the L-type plies (9) are laid in the first thickness region and the second thickness region, and the C-type plies (10) are laid in the first thickness region, the second thickness region and the third thickness region; The C-type ply (10), L-type ply (9) and I-type ply (8) are laid alternately and laid in a ply ratio of 0°:45°:90°=8:4:6 to achieve symmetrical ply along the middle layer. S3. Mold parting and laying: According to the requirements, lay the prepreg sheets of each component onto the corresponding mold parting and laying fixture; S4. Pre-molding: After the pre-molding is completed, the prepreg sheets of each component, together with their respective pre-molding installation fixtures, are sent into the autoclave for hot compaction to obtain the annular skin component (2), the left C-shaped reinforcing rib component (3), and the right C-shaped reinforcing rib component (4). S5, Co-curing: After the pre-forming by mold separation, the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) are demolded and then matched and assembled with the annular skin assembly (2). Twisted wires are filled at the R corners, and after encapsulation, they are sent to the autoclave for hot-press co-curing. S6. Demolding and molding: After co-curing, the installation fixtures of each component are removed to obtain a hollow composite material ring frame with C-shaped flange (1).

2. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: The left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) in step S1 are annular reinforcing rib structures with a C-shaped cross section. Their outer diameter is equal to the inner diameter of the annular skin assembly (2), which is used to realize that the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) are respectively fitted into the annular holes at both ends of the annular skin assembly (2).

3. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: The paving fixture mentioned in step S2 includes a molding fixture for the annular skin assembly (2), a molding fixture for the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4), and a sliding base (6) for supporting the molding fixture of the annular skin assembly (2). The forming fixture for the annular skin assembly (2) is a metal female mold fixture (5). The metal female mold fixture (5) includes an annular metal paving body (501), two inner flange metal baffles (503) and two outer limiting metal baffles (502). The two inner flange metal baffles (503) are respectively installed inside the annular metal paving body (501) near the two ends. The two outer limiting metal baffles (502) are respectively installed at both ends of the annular metal paving body (501) to ensure that the inner flanges of the C-shaped reinforcing ribs combined at both ends of the annular metal paving body (501) are formed. The annular metal paving body (501) includes a mold A, a mold B and a mold C. The connection between the mold A, the mold B and the mold C is provided with connecting ears for assembly between the three. During assembly, the mold A is located on the upper part of the sliding base (6). The molding fixtures for the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) are both male mold fixtures (7). The male mold fixture (7) is a substitute wood mold fixture (701). The substitute wood mold fixture (701) includes a limiting base (7011). The limiting base (7011) is provided with an annular support seat (7012). The annular support seat (7012) can match and fit with the groove of the C-shaped reinforcing rib assembly to realize the C-shaped reinforcing rib assembly being laid and formed on the male mold fixture (7).

4. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 3, characterized in that: The sliding base (6) includes an arc-shaped support base (601), and a sliding roller (602) is embedded along the arc-shaped surface trajectory of the arc-shaped support base (601). Each sliding roller (602) is provided with a slider (603). Limiting baffles (604) are provided at both ends of the arc-shaped support base (601). The metal female mold fixture (5) is fitted onto the arc-shaped surface of the arc-shaped support base (601). The bottom of the metal female mold fixture (5) is in contact with the slider (603). The metal female mold fixture (5) on the sliding base (6) can slide along the track of the sliding roller (602) to the limiting baffle (604), so that the annular metal paving body (501) can roll on the sliding base (6) at a certain angle, so as to realize the rolling paving and scraping of the annular skin assembly (2) in the metal female mold fixture (5).

5. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: Step S3, the mold splitting and tiling, is as follows: The annular prepreg sheet of the annular skin assembly is divided into multiple prepreg sheet segments. The prepreg sheet segments are sequentially laid onto the metal female mold fixture (5) and can be connected to form a complete annular prepreg sheet within the metal female mold fixture (5).

6. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: The parameters for hot compaction in step S4 are: temperature 50℃, pressure 0.6 MPa, and holding time 30 min.

7. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: The matching assembly in step S5 is as follows: the pre-formed left C-shaped reinforcing rib assembly (3) and right C-shaped reinforcing rib assembly (4) are demolded from the male mold tooling (7), but the pre-formed annular skin assembly (2) is not demolded from the metal female mold tooling (5). The demolded left C-shaped reinforcing rib assembly (3) and right C-shaped reinforcing rib assembly (4) are respectively connected to the inside of the two ends of the ply of the undemolded annular skin assembly (2).

8. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: The co-curing parameters in step S5 are: temperature 180±5℃, curing pressure 0.4~0.6Mpa, holding time 150~180min, and heating / cooling rate 1~3% / min.

9. The integral molding method of a hollow ring frame with C-shaped flange composite material according to claim 1, characterized in that: The demolding process described in step S6 is as follows: When removing the metal female mold tooling (5) after co-curing in step S5, remove the mold parts B and C on both sides of the upper end first, and then remove the mold part A located on the sliding base (6) in the order of demolding angle. Take out each mold part in sequence.

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