Forming method of carbon fiber composite material air inlet channel

Abstract

The invention discloses a forming method of a carbon fiber composite material air inlet channel in the technical field of aircraft air inlet channels. The forming method comprises the following steps: 1) preparing a prepreg; 2) cleaning the mold; (3) blanking; 4) paving the inner skin; when the cut prepregs are paved in an effective area of a mold according to a layer paving sequence and are paved at an R corner of a lip, except that a first layer of prepreg is paved and compacted once, vacuumizing and compacting are performed once after four layers of prepregs are paved and compacted every time for more than 15 minutes, in the vacuumizing process, raw silica gel is wrapped by an isolating membrane and is placed at the R corner of the lip, the diameter of the raw silica gel is 2 + / -0.2 cm, and the diameter of the raw silica gel is 2 + / -0.2 cm; after half of the material sheet is laid, cold pressing and pre-compaction are carried out, and at the moment, the R corner of the lip is filled with the raw silica gel; according to the method, the air inlet lip and the air inlet front section are integrally formed and designed according to the composite material, the risk that a fastener enters an engine is avoided, and meanwhile the number of parts is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, in particular to a forming method of an aircraft air inlet lip segment. Background Art

[0002] Carbon fiber reinforced resin-based composite materials have the advantages of high strength and modulus, light weight, and strong designability. In recent years, carbon fiber composite structural parts have been widely used in aerospace, weapons and equipment, aircraft and ships and other fields.

[0003] In recent years, with the increasing demand for stealth aircraft design, the rational layout of key UAV components, utilizing electromagnetic wave scattering theory, and employing targeted structural optimization to reflect electromagnetic waves away from primary threats, thereby minimizing the radar cross-sectional area of ​​airframe structural components and reducing the probability of detection by enemy radar, has become a major research hotspot in stealth aircraft. The air inlet, the passage through which the aircraft engine draws air, is one of the five major components of an aero-engine and a key component of the aircraft's propulsion system. It is also one of the components that are prone to strong radar reflection points, making the design and manufacture of the air inlet, especially the air intake lip, particularly crucial.

[0004] The air intake of some aircraft is on the top of the aircraft back. When the air passes through the lip of the air intake, it is divided. Part of the airflow enters the front end of the air intake, and part flows along the skin outside the lip. To ensure the air intake efficiency, the shape of the lip is usually more complex. At the same time, the connection with the skin above or around the lip must also be considered. The conventional design is that the lip is separated from the air intake. The lip is made of metal and the air intake is made of composite materials. The metal lip and the air intake are connected by a glue-riveted process. There are problems such as difficulty in connecting fasteners in local areas and the risk of fasteners entering the engine. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides a method for forming an air intake duct made of carbon fiber composite material, in which the air intake lip and the front section of the air intake duct are designed to be integrally formed of composite materials, and the lip and the skin are connected to the outside of the air intake duct, avoiding the risk of fasteners entering the engine, while reducing the number of parts and lightening the part weight. At the same time, the air intake duct lip is formed by a negative mold to improve the surface molding quality of the lip.

[0006] The object of the present invention is achieved as follows: A method for forming a carbon fiber composite material air intake duct comprises the following steps: Step 1) Prepare carbon fiber / epoxy resin prepreg and cool it to room temperature for use; Step 2) Clean the mold surface and select the female mold; Step 3) Use the automatic cutting machine to cut the material according to the designed layer diagram; Step 4) Lay out the inner skin according to the layup sequence; lay out the cut prepreg in the effective area of ​​the mold according to the layup sequence, layup ratio, and layup direction. When laying out the lip R corner, except for the first layer of prepreg, which is laid and compacted once, vacuum and compact it once after every four layers of prepreg are laid, and each compaction lasts for more than 15 minutes. During the vacuuming process, use a release film to wrap raw silicone and place it at the lip R corner. The diameter of the raw silicone should be 2±0.2cm. After the sheet is halfway laid, cold press pre-compact it, and the raw silicone will fill the lip R corner. Step 5) The product is sent to the autoclave for curing, and unpacked after curing and cooling; Step 6) Install a drilling jig on the mold to flanging and punch holes in the part, and then demould; Step 7) Extract the honeycomb bottom surface according to the digital model, use a blanking machine to cut honeycombs of the same size, and then cut and chamfer them; Step 8) Cellular positioning; Step 9) Lay out the outer skin according to the laying order; Step 10) The part is sent to an autoclave for curing. After curing and cooling, it is demoulded and subsequently cut, punched, and inspected to obtain a carbon fiber composite material intake lip section.

[0007] Furthermore, in step 4), the sacrificial layer is first laid at the flange position, and then pre-drawn for a set time.

[0008] Furthermore, after the first layer of prepreg is laid and pre-drawn for a set time, prefabricated carbon twisted filaments are placed at the R corner of the flange to make a right-angle transition.

[0009] Furthermore, the curing parameters in step 5) and step 10) are: Evacuate at room temperature with a vacuum degree of not less than 0.092MPa, and solidify in a can after passing the cold pressure test; Heat up to 125±5℃ at room temperature, with a heating rate of 1.0-2.0℃ / min. Set the medium temperature to 130℃. When the fastest heating thermocouple reaches 40℃, start pressurizing until it reaches 0.6MPa and then maintain the pressure. When the slowest thermocouple is heated to 120℃, keep it warm for 120-130 minutes; After cooling to below 80°C at a rate of no more than 2°C / min, release the pressure. When the temperature of the fastest cooling thermocouple drops below 60°C, open the can and complete the curing of the parts.

[0010] Furthermore, the honeycomb processing in step 7) specifically includes: according to the direction of the honeycomb core and the size of the honeycomb in the digital model, using a blanking machine to cut out a release cloth of the same size, cutting out the honeycomb according to the release cloth, and then sticking the release cloth on a hard pad, cutting out the pad of corresponding shape; sticking double-sided tape around the pad and sticking the honeycomb on it; according to the chamfer angle required by the honeycomb in the digital model, using a grinder to grind the honeycomb edge, and measuring the honeycomb angle with an angle ruler while grinding to ensure that the angle deviation is controlled within ±3°; after the honeycomb chamfer is completed, using compressed air to clean the debris, particles and other excess materials in the pores, and using a clean rag dipped in anhydrous ethanol to clean the honeycomb surface, wrapping the honeycomb core with a peelable cloth and breathable felt in turn, placing it in an oven at 70±5℃ for 1h, and then placing the honeycomb in a sealed bag, sealing it, and transporting it to a clean room.

[0011] Furthermore, the honeycomb positioning in step 8) specifically includes: laying the skin honeycomb bonding film at the bonding position between the inner skin and the honeycomb, laying the skin prepreg bonding film in other areas, overlapping the film by 2-4mm, and then vacuuming and compacting, and then placing the honeycomb on the film and vacuuming and compacting; using foam glue to bond the honeycomb joints, trimming and aligning the seams, filling the gaps that cannot be compacted with film and then pre-evacuating until there is no gap between the honeycomb and the inner skin, and filling the torn honeycomb and edge chipped corners with foam glue and then pre-evacuating.

[0012] Furthermore, step 9) outer skin laying specifically includes: after the first layer is laid, a pre-extraction is carried out, followed by laying the next layer, and finally a layer of waterproof membrane is laid in the honeycomb area, overlapping by 2-4mm, and pre-extraction is carried out for more than 2 hours. The outer skin sheets are overlapped with each other, with an overlap length of 20-30mm, and the seam positions need to be staggered layer by layer.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1) The carbon fiber composite honeycomb sandwich structure effectively reduces the weight of the product while meeting the mechanical properties of the part; 2) The autoclave process is used to reduce the porosity of the composite material and improve its structural strength; 3) Use the cold pressing pre-curing method to pre-compact the product at a certain thickness for each layer, to avoid the problems of uncompacted parts, wrinkles, bridging, and uncured internal resin caused by over-laying of prepreg at one time, thus ensuring the internal quality of the parts; 4) During the laying process, raw silicone is used to assist in compacting the R-corner area of ​​the lip, reducing the difficulty of laying in the R-corner area, improving the inter-layer compaction effect, avoiding fiber wrinkles and bridging, and ensuring the internal quality of the product. The R-corner area is filled during the final curing to reduce the risk of bag explosion; 5) Using carbon twisted wire to fill the right-angle area of ​​the flange allows for a smooth transition when laying the sheet in the right-angle area, improving the layup operability and reducing the risk of bridging and delamination in the R-corner area; 6) To avoid fiber breakage and subsequent strength impact caused by grinding when the intake lip section is assembled with the next section of the intake duct, a sacrificial layer area is added to the later grinding area during the layup design, and milling compensation is performed at the corresponding position of the mold to ensure that there is no step difference between the internal surface of the intake lip section of the intake duct after grinding and after assembly with the next section. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0015] Figure 1 This is a schematic diagram of the air intake structure obtained by the present invention.

[0016] Figure 2 This is a cross-sectional view of the air intake duct prepared according to the present invention.

[0017] Figure 3 It is a flow chart of the present invention.

[0018] Figure 4 It is a schematic diagram of the mold structure in the present invention.

[0019] Figure 5 It is a schematic diagram of the placement of twisted yarns in the present invention.

[0020] Figure 6 This is a real photo of the air intake duct made by the present invention.

[0021] Among them, there are 100 inner skin, 101 lip, 102 flange, 200 honeycomb, 300 outer skin, 400 air intake paving mold, 500 front baffle, 600 rear baffle, 700 lip paving mold, and 800 lifting ears. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] like Figure 1-2The air inlet shown is a secondary molded structural part, including a lip 101 located at the front end of the air inlet and a flange 102 located at the rear end of the air inlet. The lip 101 area is only paved with the inner skin 100, and the flanges from the middle to the tail are all paved with the inner skin 100, honeycomb 200, and outer skin 300.

[0024] like Figure 3 A method for forming a carbon fiber composite material air intake duct is shown, comprising the following steps: 1. Receive materials; Take out the carbon fiber / epoxy resin prepreg from the cold storage and cool it to room temperature before use.

[0025] 2. Mould processing; Pour anhydrous ethanol onto a clean wipe or rag, and wipe off dust, particles, and other excess materials on the mold surface that affect the surface quality of the workpiece, keeping the mold surface smooth and clean. Confirm that the tooling surface is not damaged, and the tooling cutting lines, allowance lines, coordinate system and other engraved lines are clearly visible. Apply mold release agent on the working surface three times, with an interval of 15 minutes between each application. After the application is completed, dry it at room temperature for at least 30 minutes. Figure 4 As shown, the mold includes an air intake duct paving mold 400, the front end of the air intake duct paving mold 400 is connected to a front baffle 500, the rear end of the air intake duct paving mold 400 is connected to a rear baffle 600, the outer periphery of the air intake duct paving mold 400 is provided with a lip paving mold, and an arc-shaped lip paving surface is formed between the lip paving mold 700 and the air intake duct paving mold 400, and ears 800 are provided on the front baffle 500 and the rear baffle 600.

[0026] 3. Prepreg blanking; Using Catia and Fibersim software, we created an air intake outline. Following the principle that joints between layers laid in the same direction should be staggered by at least 25mm, we used CAD software to segment, code, and sort each layer of material to create a cutting plan. This cutting plan was then imported into an automatic cutting machine to precisely cut the material, ensuring angles within 0.5°. After cutting, the material was organized according to the order of layering, and the cut pieces were inspected for integrity and damage.

[0027] 4. Prepare twisted yarn; Cut the prepreg and film into narrow strips with a width of 24mm and stick them together. Roll them into thin round strips and then put them into the special R5 twisting tool. Apply 10MPa pressure on the press at room temperature to compact the prepreg and twist them for 30 minutes. Figure 5 shown.

[0028] 5. Prepreg laying First, a sacrificial layer is laid at the folded position, followed by a 15-minute pre-pumping. The cut prepreg is then laid in the effective area of ​​the mold according to the layup sequence, layup ratio, and layup direction. After the first layer of fabric is laid, a 15-minute pre-pumping is performed. Prefabricated R5 carbon twist yarn is placed at the flange R corner to create a right-angle transition. Important points to note during this process: The fabric overlap width is 20mm. To minimize the gaps between each layer of prepreg, in addition to the first layer of prepreg being laid and compacted, vacuum compaction is performed after every four layers of prepreg are laid, with each compaction lasting at least 15 minutes. During the vacuuming process, raw silicone wrapped in an isolation film is placed at the lip R corner. The diameter of the raw silicone is controlled to be approximately 2cm to facilitate compaction at the R corner. After the sheet is halfway laid, it is pre-compacted by cold pressing. At this point, the raw silicone fills the lip R corner, reducing the probability of bag bursting.

[0029] 6. Encapsulation After the prepreg is laid, the auxiliary materials are cured and packaged.

[0030] 7. Curing Transfer the mold to the effective temperature range of the autoclave. After leak detection, cure according to the following curing parameters: ①Evacuate at room temperature with a vacuum degree of not less than 0.092MPa, and solidify in a tank after passing the cold pressure test; ②Heat to 125±5℃ at room temperature, with a heating rate of 1.0-2.0℃ / min, and the medium temperature is set to 130℃. When the fastest heating thermocouple reaches 40℃, start pressurizing until it reaches 0.6MPa and then maintain the pressure. ③ When the slowest thermocouple is heated to 120℃, keep it warm for 120min-130min; ④ Cool down to below 80℃ at a rate of no more than 2℃ / min, then release the pressure. When the temperature of the fastest cooling thermocouple drops below 60℃, the can can be opened to complete the curing of the parts.

[0031] 8. Unpacking the bag Once the mold has cooled to room temperature, the bag removal process can begin. Remove the vacuum bag and remove any auxiliary materials from the part's surface, including breathable felt, release film, and peelable fabric. Be careful not to tear the surface fibers when removing the peelable fabric.

[0032] 9. Make the hole Place the unpacked workpiece together with the mold on the drilling jig, check whether the position of the drilling jig and the workpiece is accurate after installation, and then punch holes at the flange positions on both sides.

[0033] 10. Inner skin treatment Use 180-240 grit sandpaper to polish the outer surface of the entire air inlet inner skin to increase its roughness and enhance bonding strength.

[0034] 11. Cellular processing According to the direction of the honeycomb core and the size of the honeycomb in the digital model, a blanking machine is used to cut out a release cloth of the same size. The honeycomb is cut out according to the release cloth. The release cloth is then attached to a hard pad and the pad of the corresponding shape is cut out. Double-sided tape is applied around the pad and the honeycomb is attached to it. According to the chamfer angle required by the honeycomb in the digital model, the honeycomb edge is polished with a grinder. The honeycomb angle is measured with an angle ruler while polishing to ensure that the angle deviation is controlled within ±3° to meet the design requirements (±5°). After the honeycomb is chamfered, compressed air is used to clean the debris, particles and other excess materials in the cells. The honeycomb surface is cleaned with a clean cloth dipped in anhydrous ethanol. The honeycomb core is wrapped with a peelable cloth and breathable felt in sequence. It is placed in an oven at 70±5℃ for 1 hour. The honeycomb is then sealed in a sealed bag and transported to a clean room.

[0035] 12. Honeycomb pasting positioning Lay a layer of skin and core material bonding film between the inner skin and the honeycomb positioning, and lay skin and prepreg bonding film in other areas, with the film overlapping 2-4mm, then vacuum and compact for 15 minutes, then place the honeycomb on the film and vacuum and compact for 15 minutes.

[0036] Use foam glue to bond honeycomb joints, and trim and align seams. Any gaps that cannot be compacted should be filled with adhesive film and then pre-evacuated for 15 minutes until there is no gap between the honeycomb and the inner skin. Any honeycomb tears or edge chips (within the inspection requirements) should be filled with foam glue and then pre-evacuated for 15 minutes.

[0037] 13. Outer skin laying Lay the outer skin according to the design requirements. After the first layer is laid, perform a pre-evacuation for 15 minutes before laying the next layer. Finally, lay a layer of Tedlar waterproof membrane on the honeycomb area, overlapping by 2-4mm. The pre-evacuation time should be at least 2 hours. The outer skin sheets are overlapped with each other, with an overlap length of 25mm, and the seams need to be staggered layer by layer. During the vacuuming process, since the lip R corner is a non-laying area, an isolation film can be used to wrap raw silicone to fill the entire lip R corner area to facilitate the arrangement of the vacuum bag and reduce the probability of bag explosion.

[0038] 14. Curing Transfer the mold to the effective temperature range of the autoclave. After leak detection, complete the part curing according to the following parameters: ①Evacuate at room temperature with a vacuum degree of not less than 0.092MPa, and solidify in a tank after passing the cold pressure test; ②Heat to 125±5℃ at room temperature, with a heating rate of 1.0-2.0℃ / min, and the medium temperature is set to 130℃. When the fastest heating thermocouple reaches 40℃, start pressurizing until it reaches 0.2MPa and then maintain the pressure. ③ When the slowest thermocouple is heated to 120℃, keep it warm for 120min-130min; ④ Cool down to below 80℃ at a rate of no more than 2℃ / min and then release the pressure. When the temperature of the fastest cooling thermocouple drops below 60℃, the can can be opened.

[0039] 15. Finally, the cured and cooled parts are demoulded and subsequently cut, punched, and inspected. The final product is shown in the figure below. Special attention should be paid to the fact that when making holes in composite parts, the back side should be supported with a wooden block (or bakelite block) or other methods should be adopted to prevent delamination at the hole exit.

[0040] The present invention will be further described below in conjunction with the principle of the present invention: The present invention is mainly aimed at the successful realization of difficult structural parts by completing the relevant process operations in the lip area ply manufacturing process. Since the R angle of the lip area of ​​the first section of the air inlet is small and it is in a closed shape from the outside to the inside, it is difficult to pave and compact, and it is very easy to have defects such as surface glue shortage, material shortage, and delamination. In the manufacturing process, the method of cold pressing and plugging raw silicone at the bottom R angle to assist compaction can greatly improve the ply compaction effect and avoid the occurrence of defects. However, since the vacuum pump pressure (about 0.1MPa) is relatively small during the pre-pumping process, the raw silicone cannot be filled too much to avoid pressure dispersion during the pre-pumping process and affect compaction. During the final curing, since the applied pressure is relatively large (0.6MPa), the entire lip area can be filled, and the filled raw silicone can also avoid the bursting of the vacuum bag due to the difficulty of arranging the lip. The specific principles are as follows: First, during the composite layup process, pre-compaction is performed after each layer. This can greatly compact the fiber layer. While pre-compaction can only cover relatively flat surfaces, some rounded corners and bends are difficult to fit into due to limited space, making it difficult for the vacuum bag to properly fit. Bridging is a significant risk. Furthermore, if one layer of bridging occurs, subsequent layers will continue to experience this bridging, ultimately leading to product delamination. Suitable pre-compaction tools are crucial in this situation. Raw silicone, a highly malleable elastomer with considerable compressive strength, allows for sufficient packing and filling of rounded corners. However, unlike heat-cured cured silicone, excessive raw silicone filling, due to the relatively low vacuum pump pressure, will dissipate and buffer the pre-compaction pressure due to its inherent elasticity. Therefore, only 1-2 cm of raw silicone should be used during pre-compaction. This depth ensures that the rounded corners are filled and facilitates vacuum bag organization without significantly impacting vacuum compaction, thereby enhancing pre-compaction effectiveness and product quality.

[0041] Secondly, for products with complex structures, in areas with small R-angles and many bends, the effect of a simple vacuum pump (≤0.1Mpa) will be greatly weakened as the number of sheet layers increases, and bridging and wrinkling may still occur between the layers in these areas. The cold pressing pre-curing method is to place the part in an autoclave and apply a pressure of ≥0.1MPa at low or room temperature. The high pressure assists in compacting the sheet that the vacuum pump cannot compact. Furthermore, because the autoclave applies high pressure, R-angles and bends can be filled with raw silicone to reduce the risk of bag explosion.

[0042] Furthermore, the use of carbon twisted yarn reduces operational complexity from a layup structural design perspective. This prevents bridging at the R-angles during subsequent layup. After applying the first layer of ductile, easy-to-lay plain weave fabric, prepreg carbon twisted yarn, pressed to varying R-angle sizes using a specialized twisting tool, is used to fill the R-angle areas. This allows for a smooth transition when laying the sheet material in these areas, improving layup operability and reducing the risk of bridging and delamination at the R-angles.

[0043] When the intake lip section is assembled with the next section of the intake duct, the glued assembly area will be repaired and polished. This process will cause fiber breakage, affecting strength and the internal aerodynamic surface. During the early layup and mold design, a sacrificial layer design and mold milling were added to compensate for the later polishing area. This ensures that the internal surface of the intake lip section of the intake duct and the next section after assembly are smooth.

[0044] Four improved solutions were adopted to realize the production and manufacturing of the air intake duct of the present invention, which realized the replacement of metal lip, avoided the risk of fasteners entering the engine, reduced the number of parts, and reduced the weight of parts. At the same time, the air intake duct lip was formed by female mold to improve the surface forming quality of the lip. The final formed air intake duct is as follows Figure 6 shown.

[0045] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for forming a carbon fiber composite material air intake duct, characterized in that: The following steps are involved: Step 1) prepare carbon fiber / epoxy resin prepreg and cool it at room temperature for use; Step 2) Clean the mold surface and set aside for use, and select a negative mold; Step 3) Use the automatic cutting machine to cut materials according to the designed layer diagram; Step 4) Lay the inner skin according to the laying sequence; Lay the cut prepreg in the effective area of ​​the mold according to the laying sequence, laying ratio and laying direction. When laying at the lip R corner, except for the first layer of prepreg, it is vacuumed and compacted once after laying four layers of prepreg, and each compaction lasts for more than 15 minutes. During the vacuuming process, use an isolation film to wrap the raw silicone and place it at the lip R corner. The diameter of the raw silicone is 2±0.2cm. After the sheet is half laid, it is cold pressed and pre-compacted. At this time, the raw silicone fills the lip R corner; Step 5) Send the product into the autoclave for curing, and unpack it after curing and cooling; Step 6) Install a drilling jig on the mold to flanging and punch holes in the workpiece, and then demold it; Step 7) Extract the bottom surface of the honeycomb according to the digital model, use a blanking machine to cut honeycombs of the same size, and then cut and chamfer them; Step 8) Cellular positioning; Step 9) Lay the outer skin according to the laying order; Step 10) The product is sent to an autoclave for curing. After curing and cooling, demoulding and subsequent cutting, punching and inspection are performed to obtain a carbon fiber composite material intake lip section.

2. The method for forming a carbon fiber composite material air intake duct according to claim 1, characterized in that: In step 4), the sacrificial layer is firstly laid at the flange position, and then pre-drawn for a set time.

3. The method for forming a carbon fiber composite material air intake duct according to claim 2, characterized in that: After the first layer of prepreg is laid and pre-drawn for a set time, prefabricated carbon twisted wire is placed at the R angle of the flange for right-angle transition.

4. A method for forming a carbon fiber composite material air intake duct according to any one of claims 1 to 3, characterized in that: The curing parameters in step 5) and step 10) are: Evacuate at room temperature, the vacuum degree is not less than 0.092MPa, and solidify in the tank after passing the cold pressure test; Heat up to 125±5℃ at room temperature, with a heating rate of 1.0-2.0℃ / min, and the medium temperature is set to 130℃. When the fastest heating thermocouple reaches 40℃, start pressurizing until it reaches 0.6MPa and then maintain the pressure. When the slowest thermocouple is heated to 120℃, keep it warm for 120min-130min; The temperature is lowered to below 80°C at a rate of no more than 2°C / min and then the pressure is released. When the temperature of the fastest cooling thermocouple drops below 60°C, the can is opened to complete the curing of the parts.

5. A method for forming a carbon fiber composite material air intake duct according to any one of claims 1 to 3, characterized in that: The honeycomb processing in step 7) specifically includes: according to the direction of the honeycomb core in the digital model and the size of the honeycomb, a demoulding cloth of the same size is cut out using a blanking machine, the honeycomb is cut out according to the demoulding cloth, and then the demoulding cloth is attached to a hard pad, and the pad of the corresponding shape is cut out; double-sided tape is attached around the pad and the honeycomb is attached thereto; according to the chamfer angle required by the honeycomb in the digital model, the honeycomb edge is polished by a grinder, and the honeycomb angle is measured with an angle ruler while polishing to ensure that the angle deviation is controlled within ±3°; after the honeycomb chamfering is completed, the debris, particles and other excess materials in the pores are cleaned with compressed air, and the surface of the honeycomb is cleaned with a clean rag dipped in anhydrous ethanol, and the honeycomb core is wrapped with a peelable cloth and a breathable felt in turn, and placed in an oven at 70±5℃ for 1h, and then the honeycomb is sealed in a sealed bag and transported to a clean room.

6. A method for forming a carbon fiber composite material air intake duct according to any one of claims 1 to 3, characterized in that: In step 8), the honeycomb positioning specifically includes: laying the skin honeycomb bonding film at the bonding position between the inner skin and the honeycomb, laying the skin prepreg bonding film in other areas, overlapping the film by 2-4mm, then vacuuming and compacting, then placing the honeycomb on the film, vacuuming and compacting; using foam glue to bond the honeycomb joints, trimming and aligning the seams, filling the gaps that cannot be compacted with film and then pre-evacuating until there is no gap between the honeycomb and the inner skin, and filling the torn honeycomb and edge notches with foam glue and then pre-evacuating.

7. A method for forming a carbon fiber composite material air intake duct according to any one of claims 1 to 3, characterized in that: Step 9) The outer skin paving specifically includes: after the first layer is laid, a pre-extraction is carried out, followed by the next layer of paving, and finally a layer of waterproof membrane is laid in the honeycomb area, overlapping 2-4mm, pre-extraction for more than 2h, and the outer skin sheets are overlapped with each other, the overlap length is 20-30mm, and the seam positions need to be staggered layer by layer.

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