Forming method of composite material multi-way connector

Abstract

The invention discloses a forming method of a composite material multi-way connector, and belongs to the technical field of composite material forming. A multi-way joint is decomposed into a first multi-way joint decomposition structure and a second multi-way joint decomposition structure, then the first multi-way joint decomposition structure and the second multi-way joint decomposition structure are formed through forming molds respectively, then the joint and a pipe beam are fixed in a cementing mode in the mode that a main pipe beam is connected in a sleeved mode and a secondary pipe beam is horizontally placed, and finally room-temperature curing fiber prepreg is wound on the top area of a joint connecting pipe. And curing and forming to obtain the composite material multi-way joint. The fiber continuity and the structural integrity of the multi-way connector can be effectively ensured, meanwhile, assembly of the pipe beam is facilitated, the load transfer capacity of the root of the connecting pipe is enhanced through bonding of the connecting web structure, and the winding fiber on the head of the connecting pipe can effectively restrain stripping of an adhesive layer of the multi-way connector.

Description

Technical Field

[0001] The invention relates to a molding method of a composite material multi-way joint, belonging to the technical field of composite material molding. Background Art

[0002] At present, most of the multi-way joint structures in aircraft are made of metal materials. For solar drones, the weight of each part is more stringent. Resin-based composite materials have superior properties such as light weight, high specific stiffness and strength, strong designability, good fatigue fracture resistance, good dimensional stability, and corrosion resistance. They are high-performance structural materials that are widely used in aviation, aerospace, transportation and other fields. Therefore, the application of composite multi-way joint structures is an effective way to reduce the weight of aircraft.

[0003] The main disadvantages of traditional composite multi-way joints are as follows: (1) To facilitate the subsequent assembly of the pipe beam, the joint is formed by dividing the main connecting tube into petals, and the rotation angle of each petal is not greater than 180°. This decomposition method cannot guarantee the continuity and structural integrity of the multi-way main connecting tube fiber; (2) After the pipe beam and the multi-way joint are assembled, the joint is a stress concentration structure, and each petal joint has no connection method. It is difficult to ensure the connection strength by only gluing each petal joint connecting tube to the pipe beam; (3) For multi-way joints with a connecting web structure at the root, although the connecting web surface is glued and tightened, if peeling occurs at the connecting tube head, the crack can easily extend to the connecting web position, resulting in damage to the bonding surface and failure of the joint structure. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for forming a composite multi-way joint, which effectively ensures the fiber continuity and structural integrity of the multi-way joint and facilitates the assembly of the pipe beam. The connecting web structure at the root of the connecting tube effectively enhances the load transfer capacity of the root of the connecting tube, and the winding fiber at the head of the connecting tube can effectively inhibit the peeling of the adhesive layer of the multi-way joint and avoid the failure of the multi-way joint structure.

[0005] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0006] A method for forming a composite multi-way joint comprises the following steps:

[0007] 1) In the design stage before molding, the multi-way joint structure to be molded is subjected to process type division, and is decomposed into a first multi-way joint decomposition structure and a second multi-way joint decomposition structure through a process separation surface. Both structures include a main connecting pipe, a branch connecting pipe and a connecting web structure;

[0008] 2) Cleaning the molding dies of the first multi-way joint decomposition structure and the second multi-way joint decomposition structure, applying a release agent on the surface, and then assembling the molding dies;

[0009] 3) Laying the cut fiber prepreg on the surface of the molding mold, vacuum bagging and then autoclaving;

[0010] 4) taking the solidified molding mold out of the autoclave and cooling it, and then demolding it to obtain a first multi-way joint decomposition structure and a second multi-way joint decomposition structure;

[0011] 5) Firstly, the main pipe beam is introduced into the main connecting pipe of the first multi-way joint decomposition structure, and after the glue is applied on the surface of the predetermined position of the main pipe beam, the first multi-way joint decomposition structure is pushed to the predetermined position, and then the secondary pipe beam is assembled to the branch connecting pipe of the first multi-way joint decomposition structure, and then the second multi-way joint decomposition structure coated with glue is closed accordingly; pressurize to ensure that the glue is squeezed out from all the edge positions of the main connecting pipe, branch connecting pipe and connecting web structure, and clean up the squeezed glue, and then solidify;

[0012] 6) After the glue is cured, the fiber prepreg is used to wrap the head area of ​​the main connecting pipe and the branch connecting pipe of the composite multi-way joint, and the final molding of the composite multi-way joint is completed after curing.

[0013] Preferably, the process separation surface is a middle surface of the connecting web structure.

[0014] Preferably, the main connecting pipe of the first multi-way joint decomposition structure has a rotation angle greater than 180°, which is a semi-closed structure; and the branch connecting pipe has a rotation angle of 180°.

[0015] Preferably, the rotation angle of the main connecting pipe of the second multi-way joint decomposition structure is less than 180°, which is a blocking structure; the rotation angle of the branch connecting pipe is 180°.

[0016] Preferably, the forming mold of the first multi-way connector decomposition structure comprises a left male mold, a right male mold and a core mold.

[0017] Preferably, the forming mold of the second multi-way connector decomposition structure comprises a left male mold, a right male mold and two connecting plates.

[0018] Preferably, the fiber prepreg laid on the surface of the forming mold is a fiber fabric.

[0019] Preferably, when demoulding the forming mold of the first multi-way joint decomposition structure, the core mold is firstly ejected along the axial direction of the main connecting pipe, and then the left male mold and the right male mold are ejected.

[0020] Preferably, the fiber prepreg used in the winding process is unidirectional fiber, and the resin is a room temperature curing resin.

[0021] Preferably, the width of the fiber prepreg used in the winding process does not exceed the distance from the edge of the main connecting tube and the branch connecting tube to the edge of the corresponding connecting web structure, and the number of winding turns is 2 to 4 turns.

[0022] The beneficial effects of the present invention compared with the prior art are as follows:

[0023] (1) The main connecting pipe of the first multi-way joint decomposition structure used in the present invention has a rotation angle greater than 180°, which is a semi-closed structure, and can effectively ensure the fiber continuity of the main connecting pipe of the multi-way joint. During the assembly process with the main pipe beam, the first multi-way joint decomposition structure is connected by sleeve connection, and the non-completely closed structure enables it to have a certain amount of deformation, which is convenient for sleeve connection and application of glue. The branch connecting pipe adopts a 180° semi-closed structure, which is convenient for direct bonding and assembly of the secondary pipe beam.

[0024] (2) The second multi-way joint decomposition structure used in the present invention is a blocking structure, and the rotation angle of all the connecting pipes of the second multi-way joint decomposition structure is not greater than 180°, and its main purpose is to maintain the integrity of the multi-way joint. After the first multi-way joint decomposition structure and the pipe beam are assembled, the second multi-way joint decomposition structure can be directly bonded and assembled to the pipe beam, which is simple to operate.

[0025] (3) The first multi-way joint decomposition structure used in the present invention is formed by a male mold to ensure the inner diameter of the joint pipe, effectively control the thickness of the adhesive layer, and improve the bonding effect with the pipe beam. The first multi-way joint decomposition structure is a semi-closed structure, and its demoulding direction needs to be demoulded along the axial direction of the main connecting pipe. Therefore, the mold needs to include a core mold and left and right male molds, and the core mold is first demoulded.

[0026] (4) The fiber prepreg used in the present invention for forming a multi-way joint is a fiber fabric. The multi-way joint is subjected to complex forces. Compared with unidirectional fibers, the fabric is more isotropic, which facilitates the load transfer between the main beam and the secondary beam in all directions.

[0027] (5) The multi-way joint structure used in the present invention contains a connecting web structure. After the joint and the pipe beam are transferred, the bonding surface of the connecting web structure also needs to be bonded. The root area of ​​the connecting pipe is a stress concentration location. If a winding solution is adopted, the operation is more complicated and it is difficult to ensure the consistency of the process. The connecting web structure can effectively ensure the rigidity of the root of the connecting pipe, avoid deformation and instability, and enhance the load-transmitting capacity of the multi-way joint.

[0028] (6) The fiber prepreg wound on the connecting tube head used in the present invention can effectively inhibit the peeling of the inner rubber layer of the multi-way joint connecting tube and the connecting web structure. The fiber prepreg is a unidirectional fiber, and the number of winding turns is too small to achieve the fiber tensile effect. If the number of winding turns is too many, the fiber tension of the outer layer will affect the laying of the inner layer fiber, causing the inner layer fiber to bend and unable to completely cover the connecting tube, thus losing the tensile effect. Therefore, the number of winding turns is 2 to 4 turns to ensure the fiber winding effect. The prepreg resin adopts room temperature curing resin, which can achieve the curing process effect without affecting the first and second multi-way joint decomposition structures and pipe beams of the multi-way joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A is a perspective view of the exploded structure of the first multi-way connector in the embodiment;

[0030] Figure 1B is a side view of the exploded structure of the first multi-way connector in the embodiment;

[0031] Figure 2A is a perspective view of the exploded structure of the second multi-way connector in the embodiment;

[0032] Figure 2B is a side view of the exploded structure of the second multi-way connector in the embodiment;

[0033] Figure 3A It is an assembly diagram of a forming mold for the first multi-way joint decomposition structure in the embodiment;

[0034] Figure 3B It is an exploded view of a molding die for the first multi-way joint decomposition structure in the embodiment;

[0035] Figure 4A It is an assembly diagram of a forming mold for the exploded structure of the second multi-way joint in the embodiment;

[0036] Figure 4B It is an exploded view of a molding die for the second multi-way joint decomposition structure in the embodiment;

[0037] Figure 5 It is a schematic diagram of the formation of the first multi-way joint decomposition structure in the embodiment;

[0038] Figure 6 It is a schematic diagram of the formation of the decomposed structure of the second multi-way connector in the embodiment;

[0039] Figure 7 It is a schematic diagram of the assembly of the first and second multi-way joint decomposition structures and the primary and secondary pipe beams in the embodiment;

[0040] Figure 8 Schematic diagram of the winding area of ​​the multi-way connector tube in the embodiment. DETAILED DESCRIPTION

[0041] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

[0042] The embodiment of the present invention discloses a method for forming a composite multi-way joint, which specifically includes the following forming steps:

[0043] 1. Decomposition of multi-way joint: In the design stage before molding, the multi-way joint is subjected to process type division, and the middle surface of the connecting web structure (i.e., the mold surface of the connecting web structure) is used as the process separation surface to divide the multi-way joint into two structures: a first multi-way joint decomposition structure 110 and a second multi-way joint decomposition structure 120.

[0044] The first multi-way connector decomposition structure 110 is shown in FIG. Figure 1A-1B The rotation angle α of the main connecting pipe 111 is greater than 180°, which is a semi-closed structure; the rotation angle β of the branch connecting pipe 112 is 180°, and there is a connecting web structure 113 between adjacent connecting pipes.

[0045] The second multi-way connector decomposition structure 120 is shown in FIG. Figure 2A-2B The rotation angle γ of the main connecting pipe 121 is less than 180° (there is a relationship α+γ=360°), which serves as a blocking structure during the assembly process; the rotation angle δ of the branch connecting pipe 122 is 180° (there is a relationship β+δ=360°), and there is a connecting web structure 123 between adjacent connecting pipes.

[0046] 2. Mold preparation: clean the mold, apply a mold release agent on the surface, and then assemble the mold to obtain a molding mold corresponding to the first multi-way joint decomposition structure 110 and the second multi-way joint decomposition structure 120.

[0047] The molding die of the first multi-way joint decomposition structure 110 is as follows Figure 3A-3B As shown, it is composed of a left male mold 211, a right male mold 212 and a core mold 213, which are connected in the middle by pins and screws.

[0048] The molding die of the second multi-way joint decomposition structure 120 is as follows: Figures 4A-4B As shown, it is composed of a left male mold 221, a right male mold 222 and a connecting plate 223, which are connected by pins and screws.

[0049] The first multi-way connector decomposition structure 110 has an opening position A (see Figure 1B ) The width is respectively allocated by the left male mold 211, the right male mold 212 and the core mold 213, and the width allocation must ensure that it does not affect the normal use of the mold.

[0050] 3. Multi-way joint structure laying and curing: lay the cut fiber prepregs on the surface of the forming mold, seal them in vacuum bags and then cure them. Fiber prepregs are fiber fabrics, and the fabric / resin type, laying thickness and laying method can be designed according to product requirements.

[0051] The first and second multi-way joint decomposition structures 110 and 120 are both solidified and formed by an autoclave process which can effectively ensure lossless quality.

[0052] 4. Demolding: After the cured mold is cooled, it is demolded to obtain the first multi-way joint decomposition structure 110 and the second multi-way joint decomposition structure 120. Limited by the rotation angle α of the main connecting pipe 111 of the first multi-way joint decomposition structure 110, after the pins and screws are removed, the core mold 213 must first be removed along the axial direction of the main connecting pipe 111, and then the left and right male molds 211 and 212 are removed.

[0053] Figure 5 Schematic diagram of the formation of the first multi-way connector decomposition structure 110 , wherein the structure marked in yellow is the first multi-way connector decomposition structure 110 .

[0054] Figure 6 Schematic diagram of the formation of the second multi-way connector decomposition structure 120 , wherein the structure marked in yellow is the second multi-way connector decomposition structure 120 .

[0055] 5. Bonding and assembly with pipe beam: Figure 7 As shown, the first multi-way joint decomposition structure 110 is first inserted into the main pipe beam 311, and after the glue is applied on the surface of the main pipe beam 311 at the predetermined position, the first multi-way joint decomposition structure 110 is pushed to the predetermined position. After the secondary pipe beam 312 is assembled in place, the second multi-way joint decomposition structure 120 coated with glue is closed, and pressure is applied to ensure that the glue is squeezed out of all the edge positions of all the connecting pipes and the connecting web structure (113+123), and the squeezed glue is cleaned.

[0056] Among them, the first and second multi-way joint decomposition structures 110 and 120 need to be polished and cleaned before assembly to remove the residual release agent. The multi-way joint and the pipe beam are bonded with a room temperature curing structural adhesive, and the adhesive needs to fill the bonding surface of all the joint pipes and the connecting web structure (113+123). The first multi-way joint decomposition structure 110 is a nearly closed structure. The main pipe beam 311 needs to be inserted into the main connecting pipe (111+121) of the joint along the axial direction. By using the feature that the opening width can be fine-tuned, it is opened to a certain size and then pushed into the designated position of the main pipe beam 311 coated with glue. The first multi-way joint decomposition structure 110 of the joint rebounds to squeeze out the glue evenly. Finally, the secondary pipe beam 312 is assembled and bonded. The secondary pipe beam 312 can be directly placed flat in the joint branch connecting pipe (112+122) to facilitate the simultaneous operation of the other end of the secondary pipe beam 312 and other joints.

[0057] 6. Winding: After the glue is cured, use fiber prepreg to wind the connecting pipe head area B of the multi-way joint, such as Figure 8 As shown, after curing, the multi-way joint is formed.

[0058] Among them, the fiber prepreg used for winding the connecting tube head area adopts unidirectional fiber, and the resin adopts room temperature curing resin. The type of prepreg can be selected according to product requirements. The width of the fiber prepreg does not exceed the edge of the connecting tube to the edge of the corresponding connecting web structure. The number of winding turns is 2 to 4, and all connecting tube heads need to be wound. The fiber tension must be kept consistent during the winding process. After the fiber prepreg is cured, the cut edge of the fiber is polished flat.

[0059] Two specific examples are provided below:

[0060] Example 1

[0061] A composite multi-way joint structure formed in this example is a six-way structure, with the inner diameter of the main connecting tube being 15.4mm, the inner diameter of the branch connecting tube being 10.4mm, and a connecting web structure between the connecting tubes. In this example, the joint structure fiber prepreg is a fiber prepreg obtained by impregnating a carbon fiber fabric preform with an epoxy resin system adhesive; the structural adhesive used for bonding the joint and the pipe beam is an epoxy resin system room temperature curing adhesive; the winding prepreg is a fiber prepreg obtained by impregnating a carbon fiber preform with a room temperature curing epoxy resin system adhesive. The specific implementation steps of this example are as follows:

[0062] (1) The multi-way joint structure is decomposed into a first multi-way joint decomposition structure and a second multi-way joint decomposition structure. The main connecting pipe rotation angle of the first multi-way joint decomposition structure is 270°, and the branch connecting pipe rotation angles are 180°; the main connecting pipe rotation angle of the second multi-way joint decomposition structure is 90°, and the branch connecting pipe rotation angles are 180°.

[0063] (2) A mold release agent is applied to the surface of the cleaned male mold, and then the molds are assembled and fastened with screws to obtain a molding mold corresponding to the first multi-way joint decomposition structure and the second multi-way joint decomposition structure.

[0064] (3) The first multi-way joint decomposition structure and the second multi-way joint decomposition structure of the multi-way joint are laid at the corresponding positions of the mold. According to the joint structure design requirements, the number of fiber prepreg layers is 6. After the first layer is laid, vacuum pre-pressing treatment is first performed to ensure that the fiber prepreg is fully fitted to the mold. During the laying process, the fiber is flatly fitted to the mold surface without wrinkles. After the laying is completed, it is packaged and cured using an autoclave process.

[0065] (4) After the curing is completed, the mold is cooled to room temperature, and the screws and pins are removed. The core mold of the first multi-way joint decomposition structure is removed along the main connecting pipe axial direction, and then the left and right male molds are removed. For the second multi-way joint decomposition structure, the connecting plate is first removed, and then the left and right male molds are removed.

[0066] (5) Grind and clean the mold surfaces of the first multi-way joint decomposition structure and the second multi-way joint decomposition structure. The first multi-way joint decomposition structure is inserted into the main pipe beam along the axis of the main connecting pipe. Grind and clean the main pipe beam in advance at the fixed position of the joint, and apply glue that cures at room temperature. Then, after the first multi-way joint decomposition structure is opened to a certain angle, it is pushed to the theoretical position. After the theoretical size is restored, the glue is evenly squeezed out. Then, the secondary pipe beam is placed flat on the branch connecting pipe, the joint structure at the other end is coordinated, and the position of the secondary pipe beam is adjusted so that it fits the branch connecting pipe of the first multi-way joint decomposition structure. Then, the second multi-way joint decomposition structure is assembled for blocking. Through fine-tuning and pressurization, it is ensured that glue is squeezed out at the connecting pipe and the connecting web structure of the second multi-way joint decomposition structure. Clean the extruded glue, and after the glue cures, the assembly of the main and secondary pipe beams and the first and second multi-way joint decomposition structures of the joint is completed.

[0067] (6) In each connecting tube head area, use room temperature cured fiber prepreg to wrap, the number of winding turns is 2 turns. The width of the fiber prepreg is from the edge of the connecting tube to the edge of the corresponding connecting web structure. The fiber tension is kept consistent during winding, and the fiber should not be wrinkled. After the resin is cured, the fiber joint is polished and smoothed to complete the molding of the composite multi-way joint.

[0068] Example 2

[0069] A composite multi-way joint structure formed in this example is a seven-way structure, with the inner diameter of the main connecting tube being 26.4mm, the inner diameter of the branch connecting tube being 16.4mm, and a connecting web structure between the connecting tubes. In this example, the joint structure fiber prepreg is a fiber prepreg obtained by impregnating a carbon fiber fabric preform with an epoxy resin system adhesive; the structural adhesive used for bonding the joint and the pipe beam is an epoxy resin system room temperature curing adhesive; the fiber prepreg for winding is a fiber prepreg obtained by impregnating a carbon fiber preform with an epoxy resin system adhesive that is cured at room temperature. The specific implementation steps of this example are as follows:

[0070] (1) The multi-way joint structure is decomposed into a first multi-way joint decomposition structure and a second multi-way joint decomposition structure. The main connecting pipe rotation angle of the first multi-way joint decomposition structure is 300°, and the branch connecting pipe rotation angles are 180°; the main connecting pipe rotation angle of the second multi-way joint decomposition structure is 60°, and the branch connecting pipe rotation angles are 180°.

[0071] (2) A mold release agent is applied to the surface of the cleaned male mold, and then the molds are assembled and fastened with screws to obtain a molding mold corresponding to the first multi-way joint decomposition structure and the second multi-way joint decomposition structure.

[0072] (3) The first multi-way joint decomposition structure and the second multi-way joint decomposition structure of the multi-way joint are laid at the corresponding positions of the mold. According to the joint structure design requirements, the number of fiber prepreg layers is 6. After the first layer is laid, vacuum pre-pressing treatment is first performed to ensure that the fiber prepreg is fully fitted to the mold. During the laying process, the fiber is flatly fitted to the mold surface without wrinkles. After the laying is completed, it is packaged and cured using an autoclave process.

[0073] (4) After the curing is completed, the mold is cooled to room temperature, and the screws and pins are removed. The core mold of the first multi-way joint decomposition structure is removed along the main connecting pipe axial direction, and then the left and right male molds are removed. For the second multi-way joint decomposition structure, the connecting plate is first removed, and then the left and right male molds are removed.

[0074] (5) Grind and clean the mold surfaces of the first multi-way joint decomposition structure and the second multi-way joint decomposition structure. The first multi-way joint decomposition structure is inserted into the main pipe beam along the axis of the main connecting pipe. Grind and clean the main pipe beam in advance at the fixed position of the joint, and apply glue that cures at room temperature. Then, after the first multi-way joint decomposition structure is opened to a certain angle, it is pushed to the theoretical position. After the theoretical size is restored, the glue is evenly squeezed out. Then, the secondary pipe beam is placed flat on the branch connecting pipe, the joint structure at the other end is coordinated, and the position of the secondary pipe beam is adjusted so that it fits the branch connecting pipe of the first multi-way joint decomposition structure. Then, the second multi-way joint decomposition structure is assembled for blocking. Through fine-tuning and pressurization, it is ensured that glue is squeezed out at the connecting pipe and the connecting web structure of the second multi-way joint decomposition structure. Clean the extruded glue, and after the glue cures, the assembly of the main and secondary pipe beams and the first and second multi-way joint decomposition structures of the joint is completed.

[0075] (6) In each connecting tube head area, use room temperature cured fiber prepreg to wind, the number of winding turns is 4 turns. The width of the fiber prepreg is from the edge of the connecting tube to the edge of the corresponding connecting web structure. The fiber tension is kept consistent during winding, and the fiber should not be wrinkled. After the resin is cured, the fiber joint is polished and smoothed to complete the molding of the composite multi-way joint.

[0076] The six-way and seven-way joints made of carbon fiber composite materials formed in the above example were subjected to static tests. The loads met the design specifications, and no fiber breakage, fabric cracking, delamination or abnormal noise occurred during the test.

[0077] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0078] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Appropriate modifications or equivalent substitutions of the technical solutions of the present invention made by ordinary technicians in the field should all be included in the protection scope of the present invention. The protection scope of the present invention shall be based on what is defined in the claims.

Claims

1. A method for forming a composite multi-way joint, characterized in that: The following steps are involved: 1) In the design stage before molding, the multi-way joint structure to be molded is subjected to process type division, and is decomposed into a first multi-way joint decomposition structure and a second multi-way joint decomposition structure through a process separation surface. Both structures include a main connecting pipe, a branch connecting pipe and a connecting web structure; 2) Cleaning the molding dies of the first multi-way joint decomposition structure and the second multi-way joint decomposition structure, applying a release agent on the surface, and then assembling the molding dies; 3) Laying the cut fiber prepreg on the surface of the molding mold, vacuum bagging and then autoclaving; 4) taking the solidified molding mold out of the autoclave and cooling it, and then demolding it to obtain a first multi-way joint decomposition structure and a second multi-way joint decomposition structure; 5) Firstly, the main pipe beam is introduced into the main connecting pipe of the first multi-way joint decomposition structure, and after the glue is applied on the surface of the predetermined position of the main pipe beam, the first multi-way joint decomposition structure is pushed to the predetermined position, and then the secondary pipe beam is assembled to the branch connecting pipe of the first multi-way joint decomposition structure, and then the second multi-way joint decomposition structure coated with glue is closed accordingly; pressurize to ensure that the glue is squeezed out from all the edge positions of the main connecting pipe, branch connecting pipe and connecting web structure, and clean up the squeezed glue, and then solidify; 6) After the glue is cured, the fiber prepreg is used to wrap the head area of ​​the main connecting pipe and the branch connecting pipe of the composite multi-way joint, and the final molding of the composite multi-way joint is completed after curing.

2. The molding method according to claim 1, characterized in that: The process separation surface is the middle surface of the connecting web structure.

3. The molding method according to claim 1, characterized in that: The main connecting pipe of the first multi-way joint decomposition structure has a rotation angle greater than 180°, which is a semi-closed structure; the branch connecting pipe has a rotation angle of 180°.

4. The molding method according to claim 1, characterized in that: The rotation angle of the main connecting pipe of the second multi-way joint decomposition structure is less than 180°, which is a plugging structure; the rotation angle of the branch connecting pipe is 180°.

5. The molding method according to claim 1, characterized in that: The forming mold of the first multi-way joint decomposition structure includes a left male mold, a right male mold and a core mold.

6. The molding method according to claim 1, characterized in that: The forming mold of the second multi-way joint decomposition structure includes a left male mold, a right male mold and two connecting plates.

7. The molding method according to claim 1, characterized in that: The fiber prepreg laid on the surface of the molding mold adopts fiber fabric.

8. The molding method according to claim 1, characterized in that: When demoulding the forming mold of the first multi-way joint decomposition structure, the core mold is firstly ejected along the axial direction of the main connecting pipe, and then the left male mold and the right male mold are ejected.

9. The molding method according to claim 1, characterized in that: The fiber prepreg used in the winding process is unidirectional fiber, and the resin is a room temperature curing resin.

10. The molding method according to claim 1, characterized in that: The width of the fiber prepreg used in the winding process does not exceed the distance from the edge of the main connecting pipe and the branch connecting pipe to the edge of the corresponding connecting web structure, and the number of winding turns is 2 to 4 turns.

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