Method for integrally molding a load-bearing and heat-protecting fiber reinforced resin matrix structural component

Abstract

The application discloses a kind of load heat-proof integrated fiber reinforced resin matrix structural component relay forming methods, it includes the following steps: (1) soluble core forming;(2) load forming;(3) heat-proof piece forming;(4) soluble core demoulding.The application integrates positioning rotating shaft on soluble core, realizes the accurate docking of product forming each stage, controllable appearance;Simplify the process of traditional preparation process, reduce the preparation cycle length, save manufacturing cost;Reduce the load weight of the workpiece, solve the heat matching problem of load and heat-proof piece;Improve the mechanical properties and thermal properties of the workpiece;Forming method is reliable, repeatability is high, process coordination relationship is reasonable, reduces the difficulty of forming process;Pioneeringly adopt common mould scheme, greatly save mould cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of preparation of aeronautical and aerospace load / heat protection integrated parts, and relates to a relay forming method of a load / heat protection integrated fiber-reinforced resin matrix composite material complex structure part. BACKGROUND

[0002] When an aircraft flies at high speed, a shock layer is formed on the surface of the aircraft by airflow, and a large amount of heat is generated by the compression of the gas in the shock layer. When the heat is transferred to the surface of the aircraft body, the temperature of the aircraft body rises sharply, and high temperatures are generated in different areas on the surface of the aircraft body. Therefore, heat protection treatment is required. The common heat protection materials have problems such as high cost, complex preparation and installation, low mechanical strength, and poor reusability. Therefore, it is necessary to prepare a load / heat protection integrated structure part with high efficiency, high stability and low cost to ensure flight safety. At the same time, the structure part also needs to provide a good aerodynamic shape, reduce the flight resistance, and improve the flight range.

[0003] The existing aircraft parts are generally prepared separately by dividing the load part and the heat protection part, and then forming an integral part through a gluing and sleeving process. This preparation process is suitable for parts with regular shapes. For complex structure parts, the load and heat protection parts can only be prepared in blocks and then bonded in blocks. The whole preparation process is complicated and has complex coordination relationships, which not only increases the weight and operation period of the part, but also has a thermal matching problem between the metal material and the composite material, which affects the interface performance of the load material and the heat protection material. The relay forming method of the load / heat protection integrated fiber-reinforced resin matrix composite material complex structure part provided by the present application avoids the problems existing in the prior art, reduces the preparation difficulty of the part, improves the production efficiency of the part, ensures the aerodynamic shape of the part, reduces the weight of the part, and solves the thermal matching problem of the part. Through test evaluation, the load and heat protection performance meet the requirements of high-speed flight. SUMMARY

[0004] (I) Invention purpose

[0005] The purpose of the present application is to provide a relay forming method of a load / heat protection integrated fiber-reinforced resin matrix composite material complex structure part, which meets the requirements of an aircraft for load, heat protection and aerodynamic shape.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present application provides a relay forming method of a load / heat protection integrated fiber-reinforced resin matrix material structure part, comprising the following steps:

[0008] (1) Soluble core forming: Assemble the soluble core mold, position the soluble core rotating shaft, and position the metal reinforcing frame inside the carrier at the specified location using the positioning mechanism on the rotating shaft; pour the soluble core slurry, dry and form the slurry, and surface treatment to obtain the net size core mold;

[0009] (2) Carrier forming: Cut the pre-impregnated material, lay the hat-shaped rib, place the foam, fill the hat-shaped rib corner, lay the skin, and obtain the carrier preform. Lay the auxiliary material on the surface of the carrier preform and make a bag, heat and cure the carrier preform, and cool down in the oven after curing. Remove the auxiliary material to obtain the carrier.

[0010] (3) Heat protection forming: Apply flexible adhesive to the surface of the carrier, form the heat protection preform on the surface of the adhesive, and place the heat protection preform in the heat protection forming mold. Through the RTM forming process, a rough product of a carrier / heat protection integrated fiber reinforced resin-based composite material complex structure is obtained.

[0011] (4) Soluble core demolding: Apply waterproof material to the end surface of the carrier, the surface of the heat protection, and the end surface of the heat protection. Soak the rough product in a water tank, use mechanical damage and low-pressure water flushing to remove the soluble core, remove the soluble core rotating shaft, and dry the rough product in an oven to remove residual moisture.

[0012] In step (1), the soluble core slurry includes three components, and the mass fraction of the three components is: 1-2 parts of resin powder, 6-20 parts of pure water, and 10-40 parts of ceramic powder.

[0013] In step (1), the slurry drying and forming temperature is a gradient from room temperature to 130°C, and the drying time at each temperature is 12-36 hours.

[0014] In step (1), the surface treatment includes surface repair and surface sealing. The surface repair uses a repair slurry with the same composition as the pouring slurry, with 1-2 times more ceramic powder. The surface sealing can use one or more materials such as sealing paint, adhesive release cloth, and pressure-sensitive adhesive tape.

[0015] In step (2), the preform includes a ring-shaped hat-shaped rib structure, and PMI foam is placed inside the hat-shaped rib. The PMI foam is a closed-cell, high-temperature-resistant foam.

[0016] In step (2), the skin of the preform is laid in a quasi-isotropic in-plane layup, and the transition regions are transitioned using a missing layer method.

[0017] In step (2), the prepreg comprises fibers and a prepreg, the fibers are one or more than one of glass fiber, carbon fiber, quartz fiber, high silica fiber, basalt fiber, and the resin of the prepreg can be one or modified resin of bismaleimide resin, epoxy resin, cyanate ester resin.

[0018] In step (3), the flexible adhesive can be one of epoxy resin adhesive, rubber modified epoxy resin adhesive, modified epoxy adhesive such as epoxy polyamide adhesive, silicone rubber and modified silicone rubber.

[0019] In step (3), the preform adopts one of the processes of cloth-felt lamination needle punching, 2.5D weaving and paving.

[0020] In step (4), the waterproof material can be one or more of phenolic resin, epoxy resin, silicone rubber and product silicone resin.

[0021] In step (1), the soluble core rotating shaft is also applied in steps (2) and (3) as a reference for forming the load bearing part and the heat protection part.

[0022] In step (1), the soluble core mold and the heat protection part forming mold in step (3) are shared molds, and the heat protection part forming mold is glued with a foam to obtain the soluble core mold.

[0023] The inner surface of the foam needs to be pasted with a layer of adhesive release cloth.

[0024] The sum of the adhesive layer thickness, foam thickness and adhesive release cloth thickness of each area of the heat protection part forming mold is equal to the thickness of the corresponding position of the load and heat protection integrated fiber reinforced resin matrix composite complex structure.

[0025] (Three) beneficial effects

[0026] The load and heat protection integrated fiber reinforced resin matrix structure forming method provided by the above technical solution innovatively integrates the positioning rotating shaft on the soluble core, realizes accurate docking and controllable shape in each stage of product forming, simplifies the process of traditional preparation process, reduces the preparation period, saves the manufacturing cost, reduces the load weight of the product, solves the thermal matching problem of the load bearing part and the heat protection part, improves the mechanical and thermal properties of the product, and has high repeatability, reasonable process coordination relationship and low molding process difficulty. The shared mold scheme is created, which greatly saves the mold cost. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Product forming flowchart.

[0028] Figure 2Soluble core rotating shaft schematic diagram.

[0029] Figure 3 Metal frame schematic diagram.

[0030] Figure 4 Soluble core schematic diagram.

[0031] Figure 5 Product cross-sectional view.

[0032] Figure 6 Product schematic diagram.

[0033] The figure shows: rotating shaft 1, soluble core 2, bearing 3, heat protection 4, locking bolt 5, metal frame 6, cap-shaped rib 7. DETAILED DESCRIPTION

[0034] In order to make the purpose, content and advantages of the present application more clear, the specific embodiments of the present application are described in further detail below in combination with the drawings and examples.

[0035] Referring to Figures 1 to 6 The bearing heat protection integrated fiber reinforced resin matrix structural member relay forming method of the embodiment includes the following steps:

[0036] (1) Soluble core forming

[0037] Foam adhesive is applied on the heat protection forming mold, and the custom-processed foam is bonded to the surface of the heat protection forming mold. The foam is tightly attached to the surface of the heat protection forming mold by vacuum negative pressure until the foam adhesive is completely cured. A soluble core mold is obtained by laying a glue release cloth on the foam. The soluble core mold is assembled together. The metal frame 6 inside the bearing is placed on the soluble core rotating shaft 1 as shown in Figure 3 , and locked with a locking bolt (5) to position the metal frame 6. The soluble core mold is erected, and the slurry is poured. Figure 2

[0038] Take 1 mass fraction of resin powder and place it in 9-10 mass fractions of pure water. Stir well and let stand until the solution is clear. Slowly add 19-20 mass fractions of ceramic powder to the resin solution, stir evenly, and then slowly pour into the mold. The slurry is dried at room temperature to 130°C. High-concentration soluble core slurry is prepared to fill the surface defects of the soluble core and polish it smooth. The soluble core mold as shown in Figure 4 is finally obtained. After brushing acrylic paint on the surface of the soluble core 2, a layer of glue release cloth and a layer of pressure-sensitive tape are laid on the surface.

[0039] (2) Bearing forming

[0040] In Figure 5 ​The shown soluble core cap type rib laying cap rib (7) has a thickness of 2 mm. After laying the 2 mm cap rib, PMI foam is filled in the inside of the cap rib, and pre-preg filaments are filled in the cap rib triangular area. The cap rib is checked and rammed by vacuum compaction. After the cap rib is laid, the load bearing member 3 skin is laid on the entire profile. According to the thickness and size of the skin, the laying is designed and performed. After laying, the load bearing member 3 preform is cured by vacuum extraction.

[0041] (3) Heat protection member forming

[0042] A 1.5 m to 2 mm adhesive is applied on the surface of the load bearing member, 5 layers of quartz fiber mesh cloth are laid on the adhesive, and the heat protection unit is needled on the mesh cloth. One heat protection unit is formed by one whole body of a combination of a layer of quartz mesh cloth with different gram weight and a layer of chopped quartz fiber felt with different gram weight. The whole heat protection member preform is formed based on the soluble core rotating shaft.

[0043] The foam adhesive is debonded by solvent infiltration, and then the foam is torn off the surface of the mold. The heat protection member 4 preform is installed in the mold, and the gap between the mold blocks is not greater than 0.1 mm. The specific position of the preform in the mold is determined by the cooperation of the mold and the soluble core rotating shaft. The mold is injected with resin until the mold is completely filled. After the resin is heated and cured, a rough product containing a soluble core is obtained.

[0044] (4) Soluble core demolding

[0045] Silicone rubber is applied on the surface and end face of the rough product and cured at room temperature. The soluble core is softened by placing the rough product in a water tank. The water-soluble core is removed by low-pressure water flushing. The rotating shaft is removed, and the silicone rubber on the surface of the rough product is removed. The product is placed in an oven at 100°C for 24 h to obtain a load / heat integrated fiber reinforced resin matrix composite complex structure product as shown in Figure 6

[0046] The above only describes the preferred embodiments of the present application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application. These improvements and modifications should also be considered within the protection scope of the present application.​

Claims

1. A method for relay molding of a load-bearing, heat-resistant integrated fiber-reinforced resin-based structural component, characterized in that, The method comprises the following steps: (1) soluble core forming: assembling the soluble core mold, positioning the soluble core rotating shaft, positioning the metal reinforcing frame inside the bearing part at the specified position by using the positioning mechanism on the rotating shaft while positioning the soluble core rotating shaft, pouring the soluble core slurry, drying the slurry to form, surface treatment, and obtaining the net size core mold; (2) bearing part forming: cutting the prepreg, laying the hat-shaped rib, placing the foam, filling the hat-shaped rib fillet, laying the skin, obtaining the bearing part preform, laying the auxiliary material on the surface of the bearing part preform and bagging, heating and curing the bearing part preform, cooling in the furnace after curing, removing the auxiliary material, and obtaining the bearing part; (3) heat protection part forming: applying flexible adhesive on the surface of the bearing part, forming the heat protection part preform on the surface of the adhesive, placing the heat protection part preform in the heat protection part forming mold, and obtaining the bearing and heat integrated fiber reinforced resin matrix composite complex structure product rough product by RTM forming process; (4) soluble core demolding: brushing or spraying waterproof material on the end face of the bearing part, the surface of the heat protection part and the end face of the heat protection part, immersing the rough product in the water tank, removing the soluble core by mechanical damage and low-pressure water flushing, removing the soluble core rotating shaft, and drying the rough product in the oven to remove residual water; In step (1), the soluble core slurry comprises three components, and the mass fraction of the three components is: 1-2 parts of resin powder, 6-20 parts of pure water, and 10-40 parts of ceramic powder; In step (1), the slurry drying forming temperature is gradient heating from room temperature to 130°C, and the drying time corresponding to each temperature is 12-36h; In step (1), the surface treatment includes surface repair and surface sealing, the surface repair uses repair slurry, the composition of the repair slurry is the same as that of the pouring slurry, and the fraction of ceramic powder is 1-2 times more; the surface sealing uses one or more of sealing paint, adhesive release cloth and pressure sensitive adhesive tape; In step (2), the preform includes a ring-shaped hat-shaped rib structure, and PMI foam needs to be placed inside the hat-shaped rib; the PMI foam is a closed-cell and high-temperature-resistant foam; In step (2), the skin of the preform is laid in the form of in-plane quasi-isotropic layer, and the transition regions in different regions are transitioned by layer omission; In step (2), the prepreg comprises fibers and resin of the prepreg, and the fibers are one or more of glass fiber, carbon fiber, quartz fiber, high-silica fiber and basalt fiber; the resin of the prepreg is one or modified resin of bismaleimide resin, epoxy resin and cyanate ester resin; In step (3), the flexible adhesive is one of epoxy resin adhesive, rubber modified epoxy resin adhesive, epoxy polyamide adhesive, silicone rubber and modified silicone rubber; In step (4), the waterproof material is one or more of phenolic resin, epoxy resin and silicone rubber. The soluble core mold in step (1) and the heat protection part forming mold in step (3) are shared molds, the heat protection part forming mold surface is glued with the shaped foam to obtain the soluble core mold, a layer of adhesive release cloth is laid on the inner profile surface of the shaped foam, and the sum of the adhesive layer thickness, the foam thickness and the adhesive release cloth thickness of each region of the heat protection part forming mold is equal to the thickness of the corresponding position of the bearing heat integrated fiber reinforced resin matrix composite complex structure part.

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