Integrated composite material wing and forming process thereof

Abstract

The forming process comprises the following steps: S1, respectively paving prepreg on a tool, and curing to form a composite material front spar and a composite material rear spar; s2, laying prepreg on the front edge rib foam core material to form a front edge rib; s3, a steering engine mounting groove is formed in the middle rib foam core material, an embedded block is placed in the steering engine mounting groove, then prepreg is laid and pasted, the prepreg at the position corresponding to the mounting groove is cut off, and a middle rib is formed; s4, prepreg is laid on the trailing edge rib foam core material, and a trailing edge rib is formed; s5, the front edge rib, the front spar, the middle rib, the rear spar and the rear edge rib are spliced, and connecting pieces with a plurality of metal joints are connected to the front spar and the rear spar; s6, integrally wrapping and paving the wing skin prepreg to form a composite material wing preform; and S7, paving demolding cloth, a non-porous isolating membrane, a breathable felt and a vacuum bag on the wing preform, placing the wing preform in a mold, closing the mold, pressurizing, vacuumizing, heating, completing co-curing, demolding, and opening a connecting hole to obtain the integrated composite material wing.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material forming, and in particular to an integrated composite material wing and a forming process thereof. Background Art

[0002] In order to ensure sufficient strength and rigidity, traditional wing structures often use a large amount of metal materials. For example, in the manufacturing process of large passenger aircraft wings, although materials such as aluminum alloys have good mechanical properties, they also make the wings heavier, which not only increases the overall weight of the aircraft, but also requires more fuel to overcome gravity during flight, thereby reducing fuel efficiency. In addition, in special environments such as high humidity and high salinity, the metal structure of the wing is also susceptible to corrosion. Even if there is a protective coating, long-term use may cause the protective coating to wear, thereby affecting the structural integrity of the wing. In addition, in an environment with extreme temperature changes, the thermal expansion and contraction characteristics of the wing metal material may cause stress inside the structure, and long-term accumulation may cause microcracks, etc., creating safety hazards.

[0003] Compared with traditional metal materials, composite materials have many advantages such as high specific strength, high specific stiffness, corrosion resistance, and designability, and have been widely used in aircraft structures. At present, most existing composite wing structures adopt the form of skin plus leading edge, middle rib, trailing edge, wing beam (long stringer) glued and fastened. Existing composite wings generally adopt the gluing molding process, but the bonding performance test between parts and skin is a very important content, and the test process is relatively complicated, which increases the process complexity of composite wings. Therefore, there is an urgent need for a simple molding process for composite wings. Summary of the invention

[0004] The purpose of the present invention is to provide a molding process for an integrated composite wing in view of the problem that the existing composite wing molding process is relatively complicated. The process of the present invention utilizes the molding characteristics of composite materials and can perform integrated manufacturing and compression molding for some relatively simple wing structures. It not only utilizes the advantages of composite materials such as high specific strength, light weight, and corrosion resistance, but also simplifies the complex process of existing composite wing molding.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] The present invention provides a molding process for an integrated composite material wing, the process comprising the following specific steps:

[0007] S1. Making composite front and rear wing spars: laying prepregs on the tooling, curing them, and forming composite front wing spars and composite rear wing spars of flat plate structures respectively;

[0008] S2. Preparation of leading edge ribs: providing a machined leading edge rib foam core material, and then wrapping and paving prepreg on it and staggering the joints of the prepreg to form a leading edge rib;

[0009] S3, preparation of the middle rib: providing a machined middle rib foam core material and setting a steering gear mounting groove thereon, placing an embedded block in the steering gear mounting groove, and then wrapping and paving prepreg on the middle rib foam core material and staggering the joints of the prepreg, and cutting off the prepreg corresponding to the steering gear mounting groove to form the middle rib;

[0010] S4, preparation of the trailing edge rib: providing a machined trailing edge rib foam core material, and then wrapping and paving the prepreg on the foam core material and staggering the joints of the prepreg to form the trailing edge rib;

[0011] S5, segmented assembly: sequentially splicing the leading edge rib, the composite material front spar, the middle rib, the composite material rear spar and the trailing edge rib, and then connecting a connector having a plurality of metal joints to the composite material front spar and the composite material rear spar;

[0012] S6. Overall wrapping: After splicing, the wing skin prepreg is overall wrapped and laid, and the splicing positions of the prepreg are staggered to form a composite material wing preform;

[0013] S7, co-curing: apply a release agent on the molding surface of the mold and dry it, lay a release cloth, a non-porous isolation film, a breathable felt and a vacuum bag on the composite wing preform in sequence, and then place it in the mold, close the mold, pressurize, evacuate, increase the temperature, complete co-curing, demould after cooling, open connection holes at the corresponding metal joints, and obtain an integrated composite wing.

[0014] Furthermore, a molding process for an integrated composite wing is provided: Step S1, making composite front and rear wing spars: laying prepregs with a thickness of 1.5 to 3.0 mm and a direction of 0° on a flat tooling, and then laying a release cloth, a non-porous isolation film, a breathable felt and a vacuum bag in sequence, evacuating to a vacuum degree of -0.10 to -0.08 MPa, and then placing in an autoclave and heating from room temperature to 115 to 125°C at a heating rate of 1 to 3°C / min at a pressure of 0.2 to 0.3 MPa, and then keeping warm for 85 to 95 minutes after the heating is completed to complete the curing, and respectively obtaining a composite front wing spar and a composite rear wing spar of a flat plate structure.

[0015] Furthermore, a molding process of an integrated composite wing: the foam core material in steps S2 to S4 is PET foam or PMI foam.

[0016] Furthermore, in a molding process for an integrated composite wing, the splicing locations of the prepregs in steps S2 to S4 are staggered by more than 20.0 mm.

[0017] Furthermore, a molding process for an integrated composite wing: Step S5 fills composite twist strips at the R corners after the composite front wing spar and the composite rear wing spar are spliced ​​with the foam core material.

[0018] Furthermore, in a molding process for an integrated composite wing, in step S6, the splicing of the prepregs is staggered by more than 20.0 mm.

[0019] Furthermore, a molding process for an integrated composite wing is provided: step S7, co-curing: a mold release agent is cross-coated on the molding surface of the mold and dried, a mold release cloth, a non-porous isolation film, a breathable felt and a vacuum bag are sequentially laid on the composite wing preform, and then placed in the mold, the mold is closed, and the mold is pressurized to 0.2-0.3MPa in an autoclave, and the vacuum is evacuated to a vacuum degree of -0.10-0.08MPa, and then the temperature is increased from room temperature to 115-125°C at a heating rate of 1-2°C / min. After the heating is completed, the temperature is kept for 90-120 minutes to complete the co-curing, and the mold is naturally cooled to below 60°C for demolding, and connecting holes are opened at the corresponding metal joints to obtain an integrated composite wing.

[0020] The present invention also provides an integrated composite material wing, which is formed by the above-mentioned forming process.

[0021] Beneficial effects of the present invention:

[0022] The present invention adopts an integrated composite wing forming process to avoid the bonding performance test process between the parts and the skin, thereby reducing the complexity of the composite wing process. At the same time, the composite wing also greatly reduces the overall weight of the wing and improves the various performances of the aircraft wing. The part structure of the integrated composite wing formed by the process of the present invention is simple, and only a set of mold tooling is required to ensure the outer shape surface, and the mold cost is greatly reduced.

[0023] At the same time, the process of the present invention is an integrated molding process, which effectively reduces the number of curing times in the autoclave and greatly reduces the cost of the production process; the integrated molded composite wing can also effectively reduce the number of parts and simplify the assembly process, thereby reducing the workload of the assembly link and possible assembly errors, and reducing the complexity of parts replacement during maintenance, thereby reducing manufacturing costs and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is a cross-sectional view of the integrated composite wing obtained by molding in Example 1 of the present invention;

[0026] Figure 2 A top view of the integrated composite wing obtained by molding in Example 1 of the present invention;

[0027] Figure 3 It is a top view after the segmented combination in step S5 in embodiment 1 of the present invention;

[0028] Figure 4 It is a schematic diagram of the operation of wrapping and paving each foam core material segment and the front and rear wing spars of the composite material in Example 1 of the present invention;

[0029] Figure 5 This is a schematic diagram of the operation of filling composite material twist strips at the R corner after the segment combination in step S5 in Example 1 of the present invention;

[0030] Figure 6 This is a schematic diagram of the operation of placing a composite wing preform in a mold in step S7 of Example 1 of the present invention.

[0031] Markings in the figure: 1-leading edge rib, 2-composite front wing spar, 3-middle rib, 4-composite rear wing spar, 5-trailing edge rib, 6-metal joint, 7-connector, 8-composite twist strip. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0034] Example 1

[0035] like Figures 1 to 6 As shown, this embodiment 1 provides a molding process for an integrated composite material wing, and the process includes the following specific steps:

[0036] S1. Making composite front and rear wing spars: laying carbon fiber prepreg with a thickness of 2.0 mm and a direction of 0° on a flat tooling, and then laying a demoulding cloth, a non-porous isolation film, a breathable felt and a vacuum bag in sequence, evacuating to a vacuum degree of -0.09 MPa, and then curing in an autoclave, using a pressure of 0.26 MPa throughout the process, heating from room temperature to 120°C at a heating rate of 2.0°C / min, and then keeping at 120°C for 90 minutes after the heating is completed to complete the curing; using this curing process, a composite front wing spar 2 and a composite rear wing spar 4 of a flat plate structure are obtained respectively;

[0037] S2. Preparation of leading edge ribs: providing a machined leading edge rib foam core material (using PET foam), and then wrapping and paving the carbon fiber prepreg thereon and staggering the joints of the carbon fiber prepreg by more than 20.0 mm to form a leading edge rib 1;

[0038] S3, preparation of the middle rib: providing a machined middle rib foam core material (using PET foam) and setting a steering gear mounting groove thereon, placing an embedded block in the steering gear mounting groove, and then wrapping and paving the middle rib foam core material with carbon fiber prepreg and staggering the splicing of the carbon fiber prepreg by more than 20.0 mm, and cutting off the carbon fiber prepreg corresponding to the steering gear mounting groove to form the middle rib 3;

[0039] S4, preparation of the trailing edge rib: providing a machined trailing edge rib foam core material (using PET foam), and then wrapping and paving the carbon fiber prepreg thereon and staggering the splicing of the carbon fiber prepreg by more than 20.0 mm to form the trailing edge rib 5;

[0040] S5, segmented assembly: the leading edge rib 1, the composite front spar 2, the middle rib 3, the composite rear spar 4 and the trailing edge rib 5 are sequentially spliced, and after the splicing, the composite front spar 2 and the composite rear spar 4 are spliced ​​with each section of the foam core material, and the composite twist strip 8 is filled at the R corner, and then the connector 7 with a plurality of metal joints 6 is connected to the composite front spar 2 and the composite rear spar 4 through metal fasteners (selecting 7075 aluminum alloy);

[0041] S6, overall wrapping: after completing the splicing in step S5, the wing skin prepreg is overall wrapped and laid, and the splicing of the prepreg is staggered by more than 20.0 mm to form a composite wing preform;

[0042] S7. Co-curing: first wipe the molding surface of the mold with clean gauze and acetone until it is clean and free of dirt, then apply the release agent on the molding surface of the mold in a cross manner and dry it thoroughly, then lay the release cloth, non-porous isolation film, breathable felt and vacuum bag on the outside of the above-mentioned composite wing preform in turn, place it in the above-mentioned mold after laying and close the mold, then use an autoclave to cure, pressurize it to 0.26MPa, evacuate it to a vacuum degree of -0.09MPa, and then heat it from room temperature to 120℃ at a heating rate of 2℃ / min. After the heating is completed, keep it at 120℃ for 100min to complete the co-curing, naturally cool it to below 60℃ for demoulding, and open connecting holes at the corresponding metal joints 6 to obtain an integrated composite wing.

[0043] Specifically, the pre-embedded composite front spar 2 and composite rear spar 4 in the above embodiment 1 are solidified parts, and prepreg can be selected according to actual needs and performance requirements, and the layering is defined by force analysis. The sandwich material selected in the present invention is PET foam or PMI foam, which is machined in advance according to the outer surface of the wing. The selection of PET foam or PMI foam can improve the strength of the core material and further reduce the weight of the wing; the wing skin is a laminate, and the material is selected according to actual needs (such as wave transmission requirements).

[0044] Preferably, the composite front spar 2 and the composite rear spar 4 in Example 1 are formed by laying carbon fiber prepreg in the 0° direction, which can increase the bending resistance in the 0° direction, improve the mechanical properties of the composite front spar 2 and the composite rear spar 4, and further improve the mechanical properties of the composite wing. At the same time, the present invention wraps the prepreg on each section of foam core material (including the leading edge rib foam core material, the middle rib foam core material and the trailing edge rib foam core material) in advance, which is more conducive to the co-bonding of the leading edge rib 1, the middle rib 3 and the trailing edge rib 5 with the wing spar (the composite front spar 2 and the composite rear spar 4) and is conducive to co-curing with the wing skin, which can improve the compression and bending resistance of the obtained composite wing. In areas with large changes in curvature or R corners, you can use a hot air gun to heat the prepreg according to the paving requirements, butt the prepregs, and stagger the butt gap by more than 20.0mm so that they can fit together during paving. Then use release cloth, non-porous isolation film, breathable felt, vacuum bag in turn, turn on the vacuum pump, and vacuum at room temperature to remove bubbles and compact the prepreg.

[0045] The above are preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A molding process for an integrated composite wing, characterized in that: The process includes the following steps: S1, manufacturing composite material front and rear wing spars: laying prepregs on the tooling respectively, curing, and forming composite material front wing spars (2) and composite material rear wing spars (4) of flat plate structures respectively; S2. Preparation of leading edge ribs: providing a machined leading edge rib foam core material, and then wrapping and paving prepreg on the core material and staggering the joints of the prepreg to form a leading edge rib (1); S3, preparation of the middle rib: providing a machined middle rib foam core material and setting a steering gear mounting groove thereon, placing an embedded block in the steering gear mounting groove, and then wrapping and paving the middle rib foam core material with prepreg and staggering the joints of the prepreg, and cutting off the prepreg corresponding to the steering gear mounting groove to form the middle rib (3); S4, preparation of the trailing edge rib: providing a machined trailing edge rib foam core material, and then wrapping and paving the prepreg on the foam core material and staggering the joints of the prepreg to form the trailing edge rib (5); S5, segmented assembly: sequentially splicing the leading edge rib (1), the composite material front spar (2), the middle rib (3), the composite material rear spar (4) and the trailing edge rib (5), and then connecting a connecting piece (7) having a plurality of metal joints (6) to the composite material front spar (2) and the composite material rear spar (4); S6. Overall wrapping: After splicing, the wing skin prepreg is overall wrapped and laid, and the splicing positions of the prepreg are staggered to form a composite material wing preform; S7, co-curing: applying a release agent on the molding surface of the mold and drying it, laying a release cloth, a non-porous isolation film, a breathable felt and a vacuum bag on the composite wing preform in sequence, and then placing it in the mold, closing the mold, pressurizing, evacuating, heating, completing co-curing, demoulding after cooling, and opening a connection hole at the corresponding metal joint (6) to obtain an integrated composite wing.

2. The molding process of an integrated composite wing according to claim 1, characterized in that: Step S1, manufacturing composite front and rear wing beams: laying prepregs with a thickness of 1.5 to 3.0 mm and a direction of 0° on a flat tooling, and then laying a release cloth, a non-porous isolation film, a breathable felt and a vacuum bag in sequence, evacuating to a vacuum degree of -0.10 to -0.08 MPa, and then placing in an autoclave and heating from room temperature to 115 to 125° C. at a heating rate of 1 to 3° C. / min at a pressure of 0.2 to 0.3 MPa. After heating, keeping the temperature for 85 to 95 minutes to complete curing, and obtaining a composite front wing beam (2) and a composite rear wing beam (4) of a flat structure, respectively.

3. The molding process of an integrated composite wing according to claim 1, characterized in that: The foam core material in steps S2 to S4 is PET foam or PMI foam.

4. The molding process of an integrated composite wing according to claim 1, characterized in that: In steps S2 to S4, the splicing of the prepregs is staggered by more than 20.0 mm.

5. The molding process of an integrated composite wing according to claim 1, characterized in that: Step S5 is to fill the composite material twist strip (8) at the R corner after the composite material front spar (2) and the composite material rear spar (4) are spliced ​​with the foam core material.

6. The molding process of an integrated composite wing according to claim 1, characterized in that: In step S6, the splicing of the prepregs is staggered by more than 20.0 mm.

7. The molding process of an integrated composite wing according to claim 1, characterized in that: Step S7, co-curing: a mold release agent is cross-coated on the molding surface of the mold and dried, a mold release cloth, a non-porous isolation film, a breathable felt and a vacuum bag are sequentially laid on the composite wing preform, and then the preform is placed in the mold, the mold is closed, and the preform is pressurized to 0.2-0.3 MPa in an autoclave, and the vacuum is evacuated to a vacuum degree of -0.10--0.08 MPa, and then the temperature is increased from room temperature to 115-125°C at a heating rate of 1-2°C / min. After the heating is completed, the temperature is kept for 90-120 minutes to complete the co-curing, and the preform is naturally cooled to below 60°C for demoulding, and a connection hole is opened at the corresponding metal joint (6), thereby obtaining an integrated composite wing.

8. An integrated composite wing, characterized in that: The product is obtained by molding using the molding process described in any one of claims 1 to 7.

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