Method for forming double-sided soft mold co-curing composite material of reinforcing frame with I-shaped section

Abstract

The invention discloses a forming method for a double-sided soft mold co-curing composite material of a reinforcing frame with an I-shaped section. The forming method comprises the following steps: S10, preparing a workpiece; s20, closing the mold; s30, filling is carried out; s40, paving the material sheets; s50, a core mold is installed; and S60, packaging is carried out. S70, curing is conducted; the method has the beneficial effects that by means of the method, male die paving of the upper C-shaped workpiece and the lower C-shaped workpiece on the compaction tool is achieved, so that the forming quality is improved, the skill operation difficulty is lowered, and the paving efficiency is improved; the co-curing connection of the compaction tool, the upper C-shaped workpiece and the lower C-shaped workpiece is realized, and the difference from co-bonding that secondary tank feeding is required is realized, so that the manufacturing cost is reduced.

Description

Technical Field

[0001] The invention relates to a method for forming a double-sided soft mold co-curing composite material of an I-section reinforcement frame. Background Art

[0002] In the field of advanced composite manufacturing technology, especially in the aerospace industry, higher and higher requirements are placed on the manufacturing methods of high-performance composite I-section reinforcement frames. Advanced composite materials have become ideal materials for large structures and overall structures due to their light weight, high strength, high modulus, fatigue resistance, corrosion resistance, designability and good processability. With the application of composite materials in the main load-bearing components of large passenger aircraft and the transition of UAV bulkhead materials from engineering plastics to carbon fiber composite materials, new requirements are placed on the manufacturing technology of composite I-section reinforcement frames.

[0003] The traditional composite material molding process is mainly divided into three types of bonding: secondary bonding, co-bonding and co-curing. Although secondary bonding and co-bonding are widely used, they have disadvantages such as long molding cycle, many assembly times and poor bonding strength. The co-curing molding process has attracted widespread attention from researchers due to its advantages of short processing cycle and greatly reduced cost. However, the existing co-bonding and secondary bonding molding processes have many limitations in practical applications, such as inconsistent molding quality, difficult operation, low production efficiency, etc. These problems limit the further application of composite materials in aerospace and other fields. In view of this, the present invention proposes a double-sided soft mold co-curing composite material molding method for an I-section reinforcement frame to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a method for forming a double-sided soft mold co-curing composite material of an I-section reinforcement frame to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for forming a double-sided soft mold co-cured composite material of an I-shaped cross-section reinforcement frame comprises the following steps: S10, workpiece preparation: Prepare an upper C-shaped workpiece and a lower C-shaped workpiece, and lay the upper C-shaped workpiece and the lower C-shaped workpiece on two sets of compacting tools respectively; S20, mold closing: The upper C-shaped workpiece and the compacting tool connected to the upper C-shaped workpiece are buckled on the lower C-shaped workpiece, and the upper C-shaped workpiece and the lower C-shaped workpiece are closely aligned; S30, filling: Fill the triangular portion of the fillet gap of the die joint between the upper C-shaped workpiece and the lower C-shaped workpiece in S20 with carbon twisted wire until the side end surfaces of the upper C-shaped workpiece and the lower C-shaped workpiece are in a flat state; S40, sheet laying: After S30 is completed, edge strip sheets are laid on both side end surfaces of the upper C-shaped workpiece and the lower C-shaped workpiece to form an I-beam preform; S50, core mold installation: Remove the compaction tooling of the upper C-shaped workpiece and replace it with a core mold of the same size as the compaction tooling structure; S60, packaging: The I-beam preform in S50, a set of compacting tools, and a set of core molds are vacuum packaged and compacted; S70, curing: The I-beam preform after packaging in S60, a set of compaction tools and a set of core molds are sent to the autoclave for heating and curing. After the curing is completed, the compaction tools and the core molds are taken out to the I-section reinforcement frame.

[0006] As an improvement of the above technical solution, the compacting tool has a U-shaped structure, and the core mold is made of a flexible high-temperature resistant rubber material.

[0007] As an improvement of the above technical solution, in S10, the upper C-shaped workpiece and the lower C-shaped workpiece are respectively laid in front of two sets of compacting tools, and prepreg is laid on the surface of the compacting tools.

[0008] As an improvement of the above technical solution, when the prepreg is laid on the surface of the compacting tool, vacuum sealing and compacting treatment is performed every three layers until the U-shaped structure of the compacting tool is matched with the upper C-shaped workpiece and the lower C-shaped workpiece.

[0009] As an improvement of the above technical solution, the prepreg is in the form of a combination of epoxy resin and carbon fiber unidirectional tapes.

[0010] As an improvement of the above technical solution, in S70, the curing pressure is 0.3-0.8 MPa, the curing temperature is 180±6°C, and the curing time is 120-180 min.

[0011] As an improvement of the above technical solution, in S70, when the curing pressure is applied, it is gradually increased from 0.1 MPa to the applied pressure to keep the compaction tooling force uniform.

[0012] As an improvement of the above technical solution, in S10, the upper C-shaped workpiece and the lower C-shaped workpiece have the same structural size.

[0013] Compared with the prior art, the present invention has the following beneficial effects: Through the above method, the upper C-shaped workpiece and the lower C-shaped workpiece are laid on the compaction tooling to improve the molding quality, reduce the difficulty of skill operation, and improve the laying efficiency; By realizing the co-curing connection of the compaction tooling, the upper C-shaped workpiece, and the lower C-shaped workpiece, the manufacturing cost is reduced, which is different from the co-gluing which requires two tanks. The upper C-shaped workpiece and the lower C-shaped workpiece are co-cured and formed, and no standard parts are required for riveting and fixing, which reduces the weight of the parts. Uniform pressurization through this molding method can effectively avoid the problem of internal stratification and solve the problem of assembly tolerance distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structural molding of the present invention.

[0015] In the figure: 10. compaction tool; 20. upper C-shaped workpiece; 30. lower C-shaped workpiece; 40. carbon twisted wire; 50. edge strip material plate; 60. core mold. DETAILED DESCRIPTION

[0016] 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, not all of the embodiments. 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.

[0017] Example: like Figure 1 As shown, this embodiment proposes a method for forming a double-sided soft mold co-cured composite material of an I-shaped cross-section reinforcement frame, comprising the following steps: S10, workpiece preparation: Prepare an upper C-shaped workpiece 20 and a lower C-shaped workpiece 30, and lay the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 on two sets of compacting tools 10 respectively; S20, mold closing: The upper C-shaped workpiece 20 and the compacting tool 10 connected to the upper C-shaped workpiece 20 are buckled upside down on the lower C-shaped workpiece 30, and the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 are closely aligned; S30, filling: Fill the carbon twisted wire 40 in the rounded corner gap triangle of the mold joint between the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 in S20 until the side end surfaces of the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 are in a flat state; S40, sheet laying: After S30 is completed, edge strip sheets 50 are laid on both side end surfaces of the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 to form an I-beam preform; S50, core mold installation: Remove the compacting tool 10 of the upper C-shaped workpiece 20 and replace it with a core mold 60 of the same structure and size as the compacting tool 10; S60, packaging: The I-beam preform in S50, a set of compacting tools 10, and a set of core molds 60 are vacuum packaged and compacted; S70, curing: The I-beam preform after packaging in S60, a set of compacting tools 10, and a set of core molds 60 are sent to an autoclave for heating and curing. After curing, the compacting tools 10 and the core molds 60 are taken out to the I-section reinforcement frame.

[0018] In this embodiment, the above method is used to realize the positive mold laying of the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 on the compaction tool 10, so as to improve the molding quality, reduce the difficulty of skill operation, and improve the laying efficiency; By realizing the co-curing connection of the compaction tool 10, the upper C-shaped workpiece 20, and the lower C-shaped workpiece 30, the manufacturing cost is reduced as compared with the co-gluing connection which requires two tanks. The upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 are co-cured and formed, and no standard parts are required for riveting and fixing, thereby reducing the weight of the parts; Uniform pressurization through this molding method can effectively avoid the problem of internal stratification and solve the problem of assembly tolerance distribution.

[0019] Specifically, the compacting tool 10 has a U-shaped structure, and the core mold 60 is made of a flexible high-temperature resistant rubber material.

[0020] In this embodiment, the flexible high-temperature resistant rubber material can maintain stable performance in a high-temperature environment. At the same time, it can avoid stress concentration on the upper C-type workpiece 20 and the lower C-type workpiece 30 under high temperature and high pressure, resulting in local damage to the web surface of the upper C-type workpiece 20 and the lower C-type workpiece 30, making the parts scrapped. In addition, the compaction tooling 10 of the upper C-type workpiece 20 is replaced with a core mold 60 to reduce hard contact under high-temperature and high-pressure curing, thereby ensuring the product qualification rate.

[0021] Specifically, in S10 , the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 are respectively laid in front of two groups of compacting tools 10 , and prepreg is laid on the surface of the compacting tools 10 .

[0022] Specifically, when the prepreg is laid on the surface of the compacting tool 10 , vacuum sealing and compacting are performed every three layers until the U-shaped structure of the compacting tool 10 is matched with the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 .

[0023] Specifically, the prepreg is in the form of a combination of epoxy resin and carbon fiber unidirectional tape.

[0024] In this embodiment, the mechanical strength of the I-section reinforcement frame can be effectively guaranteed by combining epoxy resin and carbon fiber unidirectional tapes.

[0025] Specifically, in S70, the curing pressure is 0.3-0.8 MPa, the curing temperature is 180±6° C., and the curing time is 120-180 min.

[0026] Specifically, in S70 , when the curing pressure is applied, it is gradually increased from 0.1 MPa to the applied pressure, so as to keep the compacting tool 10 evenly stressed.

[0027] Specifically, in S10 , the upper C-shaped workpiece 20 and the lower C-shaped workpiece 30 have the same structure and size.

[0028] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame, characterized in that: The following steps are involved: S10, workpiece preparation: Preparing an upper C-shaped workpiece (20) and a lower C-shaped workpiece (30), and laying the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) on two sets of compacting tools (10), respectively; S20, mold closing: The upper C-shaped workpiece (20) and the compacting tool (10) connected to the upper C-shaped workpiece (20) are buckled onto the lower C-shaped workpiece (30), and the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) are closely aligned; S30, filling: Filling the triangular portion of the fillet gap of the mold joint between the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) in S20 with carbon twisted wire (40) until the side end surfaces of the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) are in a flat state; S40, sheet laying: After S30 is completed, edge strip sheets (50) are laid on both side end surfaces of the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) to form an I-beam preform; S50, core mold installation: The compacting tool (10) of the upper C-shaped workpiece (20) is removed and replaced with a core mold (60) having the same structure and size as the compacting tool (10); S60, packaging: The I-beam preform in S50, a set of compacting tools (10), and a set of core molds (60) are vacuum packaged and compacted; S70, curing: The I-beam preform that has been packaged in S60, as well as a set of compacting tools (10) and a set of core molds (60) are sent to a hot autoclave for heating and curing. After the curing is completed, the compacting tools (10) and the core molds (60) are taken out to the I-section reinforcement frame.

2. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 1, characterized in that: The compacting tool (10) has a U-shaped structure, and the core mold (60) is made of a flexible, high-temperature resistant rubber material.

3. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 2, characterized in that: In S10, the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) are respectively laid in front of two sets of compacting tools (10), and prepreg is laid on the surface of the compacting tools (10).

4. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 3, characterized in that: When the prepreg is laid on the surface of the compacting tool (10), a vacuum sealing compaction process is performed every three layers until the U-shaped structure of the compacting tool (10) is matched with the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30).

5. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 4, characterized in that: The prepreg is in the form of epoxy resin carbon fiber unidirectional tape combination.

6. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 1, characterized in that: In S70, the curing pressure is 0.3-0.8 MPa, the curing temperature is 180±6° C., and the curing time is 120-180 min.

7. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 1, characterized in that: In S70, when the curing pressure is applied, it is gradually increased from 0.1 MPa to the applied pressure, so as to keep the compacting tool (10) subjected to uniform force.

8. The method for forming a double-sided soft mold co-cured composite material of an I-section reinforcement frame according to claim 1, characterized in that: In S10, the upper C-shaped workpiece (20) and the lower C-shaped workpiece (30) have the same structure and size.

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