Integral forming method of composite material hollow ring frame with C-shaped flanging

Abstract

The invention discloses an integral forming method of a composite material hollow ring frame with a C-shaped flanging, which comprises the following steps of: splitting the structure of the hollow ring frame with the C-shaped flanging into three parts, namely an annular skin component, a left side C-shaped reinforcing rib component and a right side C-shaped reinforcing rib component, paving sub-components, and then matching, assembling and integrally curing. In order to meet the requirements of the process design scheme, the forming tool is also subjected to sub-component design and comprises an annular skin paving tool, a left side C-shaped reinforcing rib paving tool, a right side C-shaped reinforcing rib paving tool and an auxiliary matching baffle. The forming quality of the composite material hollow ring frame structure with the C-shaped flanges can be guaranteed, meanwhile, the C-shaped flanges on the two sides can also play a role of reinforcing ribs, the weight reduction and compression resistance integrated effect of parts is obviously improved, and good practical value is achieved.

Description

Technical Field

[0001] The invention relates to an integral forming method of a composite material hollow ring frame with a C-shaped flange. Background Art

[0002] With the development of marine resource exploration and development, deep-sea scientific research, and the updating and iteration of underwater weapons and equipment, people have put forward higher requirements for deep submersible equipment, especially the weight reduction of submersible equipment and the ability to resist high pressure underwater. This requires the shell structure of deep-water pressure-bearing equipment to meet the requirements of low specific gravity, high strength, high modulus, deformation resistance, fatigue resistance, etc. However, the shell structure of the long cylinder section often suffers from compression buckling instability due to the increase in external pressure load caused by the increase in the submersible depth, resulting in shell buckling failure, appearance twists and turns, or even flattening. In order to avoid the occurrence of compression buckling instability, the commonly used measures are to arrange pressure rib structures such as I-shaped reinforcement ribs and L-shaped reinforcement ribs on the inner side of the pressure-bearing solid cylinder section structure to enhance compression stability. However, this method of solid cylinder section reinforcement ribs is prone to problems such as high weight and increased material costs.

[0003] Therefore, a composite hollow ring frame structure with C-shaped flanges was designed and developed. The C-shaped flanges on both sides were partially thickened to play the role of reinforcing ribs. The circumferential skin can increase the thickness of the overall barrel section. At the same time, the C-shaped cavity of the ring frame improves the structural duty ratio and reduces the weight of the barrel section, ultimately achieving the effect of weight reduction and pressure resistance integration. However, because the hollow ring frame is a special structure with C-shaped flanges on both sides, there is a risk of difficulty in demolding when using the male mold tooling for one-piece molding. When using the tooling female mold for one-piece molding, there is a problem that the flanges cannot be folded smoothly, and manual cutting and filling of the gaps in the sheet are required, which is inconvenient and inefficient to operate.

[0004] Therefore, how to form a composite hollow ring frame structure with a C-shaped flange and solve the risk of demoulding and smooth folding are still urgent problems to be solved. Summary of the invention In view of the above problems, the present invention provides a method for integrally forming a composite hollow ring frame with a C-shaped flange, wherein the structure of the hollow ring frame with a C-shaped flange is divided into three parts: an annular skin, a left C-shaped reinforcement rib, and a right C-shaped reinforcement rib. The C-shaped flanges on both sides are locally thickened to act as reinforcing ribs. The annular skin can increase the thickness of the overall barrel section. At the same time, the C-shaped cavity of the ring frame improves the structural duty cycle and reduces the weight of the barrel section, ultimately achieving the effect of weight reduction and pressure resistance integration. The present invention mainly realizes the manufacture of a composite hollow ring frame structure with a C-shaped flange through structural design and a co-curing molding process. Compared with the traditional process, the sub-assembly co-curing process and the grouped laying of components solve the problem of difficulty in integral molding of the male mold, improves production efficiency, saves material costs, and greatly guarantees the structural strength and pressure resistance of the product. The specific technical scheme is as follows: S1. Die splitting design: according to the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame is divided into an annular skin component, a left C-shaped stiffener component, and a right C-shaped stiffener component; S2. Paving design: According to the structural form of each component designed in step S1, design and prepare the corresponding paving tooling, design the ply of each component, and design different ply angles and proportions according to strength requirements; S3, split mold laying: lay the prepreg sheets of each component on the corresponding split mold laying tooling according to the requirements; S4, mold splitting preforming: after the mold splitting and paving are completed, the prepreg sheets of each component together with their respective mold splitting and paving tooling are sent into the autoclave for hot compaction to obtain the annular skin component, the left C-type stiffener component, and the right C-type stiffener component; S5, co-curing: After pre-molding, demould the left C-type stiffener assembly and the right C-type stiffener assembly, and then assemble them with the annular skin assembly, fill the twisted wire at the R corner, and send them into the autoclave for hot pressing and co-curing after packaging; S6. Demolding: After the co-curing is completed, the laying tools of each component are removed respectively to obtain a composite hollow ring frame with a C-shaped flange.

[0006] As a preferred technical solution, the left C-type stiffener assembly and the right C-type stiffener assembly in step S are annular stiffener structures with a C-shaped cross-section, and their outer diameters are equal to the inner diameters of the annular skin assembly, so as to realize that the left C-type stiffener assembly and the right C-type stiffener assembly are respectively sleeved inside the annular holes at both ends of the annular skin assembly.

[0007] As a preferred technical solution, the laying tooling in step S includes a forming tooling for an annular skin assembly, a forming tooling for a left C-shaped stiffener assembly and a right C-shaped stiffener assembly, and a sliding base for supporting the forming tooling for the annular skin assembly; The molding tool of the annular skin assembly is a metal female mold tool, which includes an annular metal paving body, two inner flanged metal baffles and two outer limit metal baffles. The two inner flanged metal baffles are respectively installed inside the annular metal paving body near the two side ends, and the two outer limit metal baffles are respectively installed at the two ends of the annular metal paving body, so as to ensure the inner side flange molding of the C-shaped reinforcement ribs assembled at the two ends of the annular metal paving body. The annular metal paving body comprises a split mold A, a split mold B and a split mold C. The connection between the split mold A, the split mold B and the split mold C is provided with a connecting ear for assembly between the three. During assembly, the split mold body A is located on the upper part of the sliding base; The molding tools of the left C-shaped reinforcement rib assembly and the right C-shaped reinforcement rib assembly are both male mold tools, and the male mold tooling is a substitute wooden mold tooling. The substitute wooden mold tooling includes a limiting base, and an annular support seat is provided on the limiting base. The annular support seat can be matched and engaged with the groove of the C-shaped reinforcement rib assembly, so as to realize the paving and molding of the C-shaped reinforcement rib assembly on the male mold tooling.

[0008] As a preferred technical solution, the sliding base includes an arc-shaped support seat, a sliding roller is embedded along the arc-shaped surface track of the arc-shaped support seat, a slider is provided inside the sliding roller, limited stoppers are provided at both ends of the support seat, the arc-shaped surface of the arc-shaped support seat is embedded with the metal female mold tooling, and the bottom of the metal female mold tooling is in contact with the slider; The metal female mold tooling on the sliding base can slide along the track track of the sliding groove to the limit baffle, and roll the annular metal paving body on the sliding base at a certain angle to achieve rolling paving and scraping of the annular skin component in the metal female mold tooling.

[0009] As a preferred technical solution, the ply design in step S is as follows: The layup design of the annular skin component is as follows: the annular skin component is divided into a plurality of layup layers according to its thickness, and the plurality of layup layers are stacked; The ply design of the left C-type stiffener assembly and the right C-type stiffener assembly is as follows: S-: the left C-shaped stiffener assembly and the right C-shaped stiffener 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 the second thickness zone> the first thickness zone> the third thickness zone; S-: According to the thickness zoning in step S-, the plies of the left C-type stiffener assembly and the right C-type stiffener assembly are respectively divided into I-type plies, L-type plies, and C-type plies; the I-type plies are laid in the second thickness zone, the L-type plies are laid in the first thickness zone and the second thickness zone, and the C-type plies are laid in the first thickness zone, the second thickness zone, and the third thickness zone; The C-type plies, L-type plies and I-type plies are laid alternately and in a ply ratio of °:°:°=::, so as to achieve vertical symmetry of the plies along the middle layer.

[0010] As a preferred technical solution, step S of splitting and paving is as follows: The annular prepreg sheet of the annular skin assembly is divided into a plurality of prepreg sheet parts, and the prepreg sheet parts are sequentially laid on the metal female mold tooling, and can be connected to form a complete annular prepreg sheet in the metal female mold tooling; As a preferred technical solution, the parameters of the hot compaction in step S4 are: temperature 50° C., pressure 0.6 MPa, and heat and pressure holding time 30 min.

[0011] As a preferred technical solution, the matching assembly described in step S5 is specifically as follows: the preformed left C-type stiffener assembly and the right C-type stiffener assembly are demolded from the male mold tooling respectively, but the preformed annular skin assembly is not demolded from the metal female mold tooling, and the demolded left C-type stiffener assembly and the right C-type stiffener assembly are respectively sleeved inside the two ends of the ply of the un-demolded annular skin assembly.

[0012] As a preferred technical solution, the co-curing parameters in step S5 are: temperature 180±5°C, curing pressure 0.4-0.6Mpa, insulation time 150-180min, and heating and cooling rate 1-3% / min.

[0013] As a preferred technical solution, the demolding molding described in step S6 is specifically as follows: when removing the metal female mold tooling after co-curing in step S5, first remove the split mold B and split mold C on both sides of the upper end according to the demolding angle, and then remove the split mold A located on the sliding base, and take out each split mold body in turn.

[0014] The beneficial effects of the present invention are as follows: (1) Compared with the traditional solid barrel section, the composite hollow ring frame structure with C-shaped flanges in the present invention has local thickening of the C-shaped flanges on both sides to play the role of reinforcing ribs. The annular skin can increase the thickness of the overall barrel section. At the same time, the C-shaped cavity of the ring frame improves the structural occupancy ratio and reduces the weight of the barrel section, ultimately achieving the effect of weight reduction and pressure resistance integration.

[0015] (2) The present invention divides the structure of the hollow ring frame with C-shaped flange into three parts: annular skin, left C-shaped reinforcement ribs, and right C-shaped reinforcement ribs. The process of laying and co-curing the sub-components is adopted to solve the problem of difficulty in integrally forming the male mold of the hollow ring frame. The laying process of the two components can be carried out simultaneously, which simplifies the laying process, improves production efficiency, saves material costs, greatly ensures the structural strength and compressive strength of the product, and greatly reduces the production cost while ensuring the quality of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A composite hollow ring frame structure with a C-shaped flanging edge and a composite hollow ring frame integrally formed by a method for forming the composite hollow ring frame with a C-shaped flanging edge; Figure 2 for Figure 1 Disassembly diagram; Figure 3 Schematic diagram of the matching assembly of the C-type stiffener assembly and the annular skin assembly Figure 4A schematic diagram of a molding tool for an integral molding method of a composite hollow ring frame with a C-shaped flange; Figure 5 Schematic diagram of the disassembly of the molding tooling Figure 6 Schematic diagram of disassembly of metal female mold tooling Figure 7 Schematic diagram of the main body of the ring paving Figure 8 for Figure 4 Disassembly diagram; Fig. 9 Schematic diagram of the sliding base structure Fig.10 A schematic diagram of C-shaped reinforcement rib laying in an integral forming method of a composite hollow ring frame with a C-shaped flange; Fig.11 A schematic diagram of laying out an annular skin component of an integral forming method of a hollow ring frame of composite material with a C-shaped flange; Fig.12 Schematic diagram of male mold tooling laying.

[0017] The meanings of the marks in the figure are as follows: 1. Hollow ring frame of composite material with C-shaped flange; 2. Annular skin assembly; 3. C-shaped reinforcement rib on the left; 4. C-shaped reinforcement rib on the right; 5. Metal female mold tooling; 501. Annular metal paving body; A. Parting mold A; B. Parting mold B; C. Parting mold C; 502. External limit metal baffle; 503. Internal flange metal baffle; 6. Sliding base; 601. Arc support seat; 602. Sliding roller; 603. Sliding block; 604. Limit baffle; 7. Male mold tooling; 701. Substitute wood mold tooling; 7011. Limit base; 7012. Annular support seat; 8. I-type reinforcement layer; 9. L-type reinforcement layer; 10. C-type reinforcement layer; 11. Isolation film; 12. Surface breathable material; 13. Vacuum bag; 14. Demolding material. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with embodiments.

[0019] Example 1 This embodiment is a method for integrally forming a hollow ring frame of composite material with a C-shaped flange, and the steps are as follows: S1. Die splitting design: according to the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame with C-shaped flange 1 is divided into an annular skin component 2, a left C-shaped stiffener component 3, and a right C-shaped stiffener component 4; S2. Paving design: According to the structural form of each component designed in step S1, design and prepare the corresponding paving tooling, design the ply of each component, and design different ply angles and proportions according to strength requirements; S3, split mold laying: lay the prepreg sheets of each component on the corresponding split mold laying tooling according to the requirements; S4, mold splitting preforming: after the mold splitting and paving are completed, the prepreg sheets of each component together with their respective mold splitting and paving tooling are sent into the autoclave for hot compaction to obtain the annular skin component 2, the left C-type stiffener component 3, and the right C-type stiffener component 4; S5, co-curing: After pre-molding, the left C-shaped stiffener assembly 3 and the right C-shaped stiffener assembly 4 are demoulded, and then matched and assembled with the annular skin assembly 2, and twisted wire is filled at the R corner, and then packaged and sent into the autoclave for hot pressing and co-curing; S6. Demolding: After the co-curing is completed, the laying tools of each component are removed respectively to obtain a composite hollow ring frame 1 with a C-shaped flange.

[0020] Reference Figures 1 to 12 In the integral forming method of the hollow ring frame of composite material with C-shaped flange described in this embodiment, the left C-shaped stiffener component 3 and the right C-shaped stiffener component 4 in step S1 are annular stiffener structures with C-shaped cross-sections, and their outer diameters are equal to the inner diameters of the annular skin component 2, which are used to realize that the left C-shaped stiffener component 3 and the right C-shaped stiffener component 4 are respectively sleeved inside the annular holes at both ends of the annular skin component 2.

[0021] In this embodiment, the paving tooling in step S2 includes a forming tooling for the annular skin component 2, a forming tooling for the left C-shaped stiffener component 3 and the right C-shaped stiffener component 4, and a sliding base 6 for supporting the forming tooling of the annular skin component 2; the forming tooling of the annular skin component 2 is a metal female mold tooling 5, and the metal female mold tooling 5 includes an annular metal paving body 501, two inner flanged metal baffles 503 and two outer limit metal baffles 502, and the two inner flanged metal baffles 503 are respectively installed Two outer limit metal baffles 502 are respectively installed at the two ends of the annular metal paving body 501, which are used to ensure that the inner side flanging of the C-shaped reinforcing ribs assembled at the two ends of the annular metal paving body 501 is formed; wherein the annular metal paving body 501 includes a split mold A, a split mold B and a split mold C, and the connection between the split mold A, the split mold B and the split mold C is provided with a connecting ear for assembly between the three; during assembly, the split mold body A is located on the upper part of the sliding base 6; The molding tools of the left C-shaped stiffener assembly 3 and the right C-shaped stiffener assembly 4 are both male mold tools 7, and the male mold tools 7 are wooden mold substitute tools 701. The wooden mold substitute tools 701 include a limiting base 7011, and the limiting base 7011 is provided with an annular support seat 7012. The annular support seat 7012 can be matched and engaged with the groove of the C-shaped stiffener assembly, so as to realize the paving and molding of the C-shaped stiffener assembly on the male mold tooling 7.

[0022] In this embodiment, the sliding base 6 includes an arc-shaped support seat 601, and a sliding roller 602 is embedded along the arc-shaped surface track of the arc-shaped support seat 601. A sliding block 603 is provided inside the sliding roller 602. Limit baffles (604) are provided at both ends of the support seat 601. The arc-shaped surface of the arc-shaped support seat 601 is embedded with the metal female mold tooling 5, and the bottom of the metal female mold tooling 5 is in contact with the sliding block 603; the metal female mold tooling 5 on the sliding base 6 can slide along the track track of the sliding roller 602 to the limit baffle (604), and roll the annular metal paving body 501 on the sliding base 6 at a certain angle, so as to realize the rolling paving and scraping of the annular skin component 2 in the metal female mold tooling 5.

[0023] In the method for integrally forming the hollow ring frame of composite material with C-shaped flanges described in this embodiment, the layering design in step S2 is as follows: The ply design of the annular skin component 2 is as follows: the annular skin component 2 is divided into a plurality of plies according to its thickness, and the plurality of plies are stacked; The ply design of the left C-shaped stiffener assembly 3 and the right C-shaped stiffener assembly 4 is as follows: S2-1: Divide the left C-shaped stiffener assembly 3 and the right C-shaped stiffener assembly 4 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 the second thickness zone> the first thickness zone> the third thickness zone; S2-2: According to the thickness zoning in step S2-1, the plies of the left C-type stiffener assembly 3 and the right C-type stiffener assembly 4 are respectively divided into an I-type ply 8, an L-type ply 9, and a C-type ply 10; the I-type ply 8 is laid in the second thickness zone, the L-type ply 9 is laid in the first thickness zone and the second thickness zone, and the C-type ply 10 is laid in the first thickness zone, the second thickness zone, and the third thickness zone; The C-type ply 10, L-type ply 9 and I-type ply 8 are laid alternately and in a ply ratio of 0°:45°:90°=8:4:6, so as to achieve vertical symmetry of the ply along the middle layer.

[0024] The integral forming method of the hollow ring frame of composite material with C-shaped flanges described in this embodiment, step S3 of splitting and paving is as follows: The annular prepreg sheet of the annular skin assembly is divided into a plurality of prepreg sheet parts, and the prepreg sheet parts are sequentially laid on the metal female mold tooling 5, and can be connected to form a complete annular prepreg sheet in the metal female mold tooling 5; In the integral forming method of the hollow ring frame of composite material with C-shaped flange described in this embodiment, the parameters of the hot compaction in step S4 are: temperature 50° C., pressure 0.6 MPa, and heat and pressure holding time 30 min.

[0025] The integral forming method of the hollow ring frame of composite material with C-shaped flange described in this embodiment, the matching assembly described in step S5 is specifically: the preformed left C-shaped stiffener component 3 and the right C-shaped stiffener component 4 are demolded from the male mold tooling 7 respectively, but the preformed annular skin component 2 is not demolded from the metal female mold tooling 5, and the demolded left C-shaped stiffener component 3 and the right C-shaped stiffener component 4 are respectively sleeved on the inner ends of the ply of the undemolded annular skin component 2.

[0026] In the integral forming method of the hollow ring frame of composite material with C-shaped flange described in this embodiment, the co-curing parameters in step S5 are: temperature 180±5°C, curing pressure 0.4-0.6Mpa, insulation time 150-180min, and heating and cooling rate 1-3% / min.

[0027] The overall forming method of the hollow ring frame of composite material with C-shaped flange described in this embodiment, the demolding molding described in step S6 is specifically as follows: when removing the metal female mold tooling 5 co-cured in step S5, first remove the split mold B and split mold C on both sides of the upper end according to the demolding angle, and then remove the split mold A located on the sliding base 6, and take out each split mold body in sequence.

[0028] Taking a C-shaped flanging hollow ring frame structure as an example, the specific steps of the integral forming method of the C-shaped flanging composite material hollow ring frame described in this embodiment are described in detail as follows: S1. Die splitting design: according to the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame is divided into an annular skin component 2, a left C-shaped stiffener component 3, and a right C-shaped stiffener component 4; S2, laying design: according to the circumferential length of the annular skin component 2 and the thickness partition of the left and right C-shaped stiffener components 4, Fibersim software is used to respectively design the different configuration pieces and design the proportions of different laying angles according to the strength requirements. At the same time, the metal female mold tooling 5 used for laying the annular skin component 2 and the laying tooling 7 used for the left and right C-shaped stiffener components 4 are prepared, and the cleaning and demoulding material 14 are brushed; S3, split mold paving: the annular skin assembly 2 is paved on the metal female mold tooling 5; the reinforcement layers 8, 9, 10 of the left and right C-shaped reinforcement rib assemblies 4 are paved on the male mold tooling 7, and the paving of the two is carried out simultaneously to improve efficiency. The reinforcement layers mainly include three configurations of C, I, and L, and the three configurations are paved alternately.

[0029] S4, pre-molding of split molds: firstly, conduct vacuum pre-pressing and sealing leak detection on the split molds completed in step S3. After the leak detection is qualified, use auxiliary material isolation film 11, surface breathable material 12, and vacuum bag 13 to encapsulate each split mold, and then evacuate and pre-press. Send the encapsulated parts and tooling into the autoclave, set the autoclave parameters as follows: temperature 50℃, pressure 0.6Mpa, heat preservation and pressure holding time 30min, and hot press the encapsulated components in the autoclave. After removing the autoclave, the annular skin component 2, the left C-type stiffener component 3, and the right C-type stiffener component 4 can be obtained; S5, co-curing: After pre-molding by splitting the mold, demold the left C-type stiffener assembly 3 and the right C-type stiffener assembly 4 from the male mold tooling 7, and do not demold the annular skin assembly 2. Match the obtained left C-type stiffener assembly 3 and the right C-type stiffener assembly 4 to the inside of the annular ply at both ends of the annular skin assembly 2. Check the triangular area between the stiffener assembly and the annular skin assembly 2 and fill it with an appropriate amount of carbon twisted wire to ensure that the fit is completely gapless. Then, pre-compact and package it with the surface breathable material 12. Then, install and assemble the outer limit metal baffles and the inner flange metal baffles 503 on both sides of the metal female mold tooling 5. After completion, send it to the autoclave, set the parameters of the autoclave for hot pressing and co-curing, and then match and assemble it with the annular skin assembly 2, fill the twisted wire at the R corner, and send it to the autoclave for hot pressing and co-curing after packaging. S6, demoulding and molding: after the co-curing in step S5, the metal female mold tooling 5 is removed, and the split molds B and C on both sides of the upper end are first removed according to the demoulding angle, and then the split mold A located on the sliding base (6) is removed, and each split mold body is taken out in sequence, and the remaining paving is removed to obtain a C-shaped flanging composite hollow ring frame.

[0030] In general, the method of the present invention is guided by theory in practice. Compared with the traditional solid barrel section, the design of the C-shaped reinforcement layer on both sides of the bonding area can not only achieve weight reduction but also ensure the compressive resistance. The present invention adopts the whole paving layer and the reinforcement layer sub-assembly and then installs. The paving process of the two components can be carried out at the same time, which simplifies the paving process and improves production efficiency. It greatly reduces the production cost while ensuring the quality of the parts, and also avoids the damage of parts caused by post-machining. The three different configurations of the reinforcement layer simultaneously assist in alternating paving at different angles, which greatly ensures the structural strength and compressive resistance of the product. The technical problem is effectively solved in a simple way, the scheme is ingeniously conceived, and has good practical value.

[0031] It will be apparent to those skilled in the art that the 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 the spirit or essential features of the invention. 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, and it is intended that all variations within the meaning and scope of the elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0032] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for integrally forming a hollow ring frame of composite material with a C-shaped flange, characterized in that: The steps include: S1. Die splitting design: according to the structural form of the hollow ring frame with C-shaped flange, the hollow ring frame with C-shaped flange (1) is divided into an annular skin component (2), a left C-shaped stiffener component (3), and a right C-shaped stiffener component (4); S2. Paving design: According to the structural form of each component designed in step S1, design and prepare the corresponding paving tooling, design the ply of each component, and design different ply angles and proportions according to strength requirements; S3, split mold laying: lay the prepreg sheets of each component on the corresponding split mold laying tooling according to the requirements; S4, split mold preforming: After the split mold paving is completed, the prepreg sheets of each component together with their respective split mold paving tooling are sent into a hot autoclave for hot compaction to obtain an annular skin component (2), a left C-shaped stiffener component (3), and a right C-shaped stiffener component (4); S5, co-curing: After pre-molding, the left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4) are demoulded, and then matched and assembled with the annular skin assembly (2), and twisted wire is filled at the R corner. After packaging, they are sent into an autoclave for hot pressing and co-curing; S6, demoulding and molding: After the co-curing is completed, the laying tools of each component are removed respectively, and a composite hollow ring frame (1) with a C-shaped flange can be obtained.

2. The integral forming method of a composite hollow ring frame with a C-shaped flange according to claim 1, characterized in that: The left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4) in step S1 are annular stiffener structures with a C-shaped cross-section, and their outer diameters are equal to the inner diameters of the annular skin assembly (2), so as to enable the left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4) to be respectively sleeved inside the annular holes at both ends of the annular skin assembly (2).

3. The integral forming method of a composite hollow ring frame with C-shaped flange according to claim 1, characterized in that: The laying tooling in step S2 comprises a forming tooling for the annular skin assembly (2), a forming tooling for the left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4), and a sliding base (6) for supporting the forming tooling for the annular skin assembly (2); The molding tool of the annular skin assembly (2) is a metal female mold tool (5), and the metal female mold tool (5) comprises an annular metal paving body (501), two inner flanged metal baffles (503) and two outer limit metal baffles (502), wherein the two inner flanged metal baffles (503) are respectively installed inside the annular metal paving body (501) near the two side end positions, and the two outer limit metal baffles (502) are respectively installed at the two ends of the annular metal paving body (501) to ensure that the inner side flanges of the C-shaped reinforcing ribs assembled at the two ends of the annular metal paving body (501) are formed; The annular metal paving body (501) comprises a split mold A, a split mold B and a split mold C, and connecting ears are provided at the connection between the split mold A, the split mold B and the split mold C for assembling the three. During assembly, the split mold body A is located on the upper part of the sliding base (6); The molding tools of the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) are both male mold tools (7), and the male mold tool (7) is a substitute wooden mold tool (701). The substitute wooden mold tool (701) comprises a limiting base (7011), and an annular support seat (7012) is arranged on the limiting base (7011). The annular support seat (7012) can be matched and engaged with the groove of the C-shaped reinforcing rib assembly, so as to realize the paving molding of the C-shaped reinforcing rib assembly on the male mold tool (7).

4. The integral forming method of a composite hollow ring frame with C-shaped flange according to claim 3, characterized in that: The sliding base (6) comprises an arc-shaped support seat (601), a sliding roller (602) is embedded along the arc-shaped surface track of the arc-shaped support seat (601), a sliding block (603) is provided inside the sliding roller (602), and limit baffles (604) are provided at both ends of the support seat (601). The arc-shaped surface of the arc-shaped support seat (601) is embedded with the metal female mold tooling (5), and the bottom of the metal female mold tooling (5) is in contact with the sliding block (603); The metal female mold tooling (5) on the sliding base (6) can slide along the track of the sliding roller (602) to the limit baffle (604), and roll the annular metal paving body (501) on the sliding base (6) at a certain angle, so as to realize rolling paving and scraping of the annular skin component (2) in the metal female mold tooling (5).

5. The integral forming method of a composite hollow ring frame with C-shaped flange according to claim 1, characterized in that: The ply design in step S2 is as follows: The ply design of the annular skin component (2) is as follows: the annular skin component (2) is divided into a plurality of ply layers according to its thickness, and the plurality of ply layers are stacked; The ply design of the left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4) is as follows: S2-1: dividing the left C-shaped reinforcing rib assembly (3) and the right C-shaped reinforcing rib assembly (4) 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 the second thickness zone> the first thickness zone> the third thickness zone; S2-2: According to the thickness zoning in step S2-1, the plies of the left C-type stiffener assembly (3) and the right C-type stiffener assembly (4) are respectively divided into an I-type ply (8), an L-type ply (9), and a C-type ply (10); the I-type ply (8) is laid in the second thickness zone, the L-type ply (9) is laid in the first thickness zone and the second thickness zone, and the C-type ply (10) is laid in the first thickness zone, the second thickness zone, and the third thickness zone; The C-type ply (10), the L-type ply (9) and the I-type ply (8) are laid alternately and laid according to a ply ratio of 0°:45°:90°=8:4:6, so as to achieve vertical symmetry of the ply along the middle layer.

6. The integral forming method of a composite hollow ring frame with C-shaped flange according to claim 1, characterized in that: Step S3: mold splitting and paving are as follows: The annular prepreg sheet of the annular skin assembly is divided into a plurality of prepreg sheet parts, which are sequentially laid on a metal female mold tooling (5) and can be connected inside the metal female mold tooling (5) to form a complete annular prepreg sheet.

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

8. The integral forming method of a composite hollow ring frame with C-shaped flange according to claim 1, characterized in that: The matching assembly in step S5 specifically comprises: demolding the preformed left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4) from the male mold tooling (7), but not demolding the preformed annular skin assembly (2) from the metal female mold tooling (5), and respectively sleeve-fitting the demolded left C-shaped stiffener assembly (3) and the right C-shaped stiffener assembly (4) inside the two ends of the ply of the un-demolded annular skin assembly (2) on the inside.

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

10. The integral forming method of a composite hollow ring frame with C-shaped flange according to claim 1, characterized in that: The demoulding molding described in step S6 is specifically as follows: when removing the metal female mold tooling (5) after co-curing in step S5, first remove the split mold B and split mold C on both sides of the upper end according to the demoulding angle, and then remove the split mold A located on the sliding base (6) in this order, and take out each split mold body in turn.

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