A forming tooling and forming method for a "J"-type honeycomb sandwich structure

Abstract

The present invention relates to a forming tooling and a forming method for a "J"-type honeycomb sandwich structure, including a main body support mold, a lateral support mold, and a combined upper pressing plate. The upper surface of the main body support mold matches the lower surface of the "C"-type ply group of the "J"-type composite honeycomb sandwich structure; the lateral support mold is detachably installed on one side of the main body support mold, and the working surface of the lateral support mold matches the outer surface of the "1"-type ply group of the "J"-type composite honeycomb sandwich structure; the combined upper pressing plate includes a hard pressing plate and a soft pressing plate, and the hard pressing plate and the soft pressing plate respectively correspond to the plate-plate area and the plate-core area of the upper surface of the "Z"-type ply group of the "J"-type composite honeycomb sandwich structure. During encapsulation, lateral pressing plates, hard pressing plates, and soft pressing plates with different stiffnesses are used to press different areas of the part respectively, which is conducive to pressure transfer during autoclave forming, and the formed part has good internal quality and high dimensional accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material manufacturing, and particularly to a forming tooling and a forming method for a "J"-type honeycomb sandwich structure. Background Art

[0002] Due to its high specific strength, high specific stiffness, strong designability, good anti-fatigue fracture performance, corrosion resistance, good dimensional stability, and convenience for large-area integral forming, composite materials have become one of the most important contemporary aviation structural materials. The honeycomb sandwich structure is a structural material with a very large strength-to-weight ratio. Compared with solid materials, the effective materials used in the honeycomb sandwich structure composite material are only 1% - 5% of the replaced materials. It is obviously a lightweight material with great potential that saves materials and energy.

[0003] In the aircraft structure design, as a lightweight and high-stiffness structural member, the "J"-type composite honeycomb sandwich structure is increasingly widely used in components such as aircraft wing surfaces and vertical tails. However, how to simplify the laying and assembly operations and reduce the manufacturing cost while ensuring the forming dimensional accuracy and internal quality of the "J"-type composite honeycomb sandwich structure is a technical problem with great difficulty. Summary of the Invention

[0004] The embodiments of the present invention provide a forming tooling and a forming method for a "J"-type honeycomb sandwich structure.

[0005] In a first aspect, an embodiment of the present invention provides a forming tooling for a "J"-type honeycomb sandwich structure, including a main body support mold, a lateral support mold, and a combined upper pressing plate. The upper surface of the main body support mold matches the lower surface of the "C"-type ply group of the "J"-type composite honeycomb sandwich structure; the lateral support mold is detachably installed on one side of the main body support mold, and the working surface of the lateral support mold matches the outer surface of the "1"-type ply group of the "J"-type composite honeycomb sandwich structure; the combined upper pressing plate includes a hard pressing plate and a soft pressing plate, and the hard pressing plate and the soft pressing plate respectively correspond to the plate-plate area and the plate-core area of the upper surface of the "Z"-type ply group of the "J"-type composite honeycomb sandwich structure.

[0006] Further, it further includes a lateral pressing plate, which is detachably installed on one side of the main body support mold, and the working surface of the lateral pressing plate matches the outer surface of the "1"-type ply group of the "J"-type composite honeycomb sandwich structure.

[0007] Further, the lateral pressing plate is made of a prepreg curing molding material same as that of the "J"-type composite honeycomb sandwich structure.

[0008] Further, the layup of the lateral pressing plate is [+45 / -45 / 0 / 90]ns, where 2≤n≤4.

[0009] Further, the length of the lateral pressing plate is L and the width is H, and the length of the "1"-type layup group of the "J"-type composite honeycomb sandwich structure is L0 and the width is H0, where 40mm≤L - L0≤100mm and 0mm≤H - H0≤50mm.

[0010] Further, a limit card slot for partially accommodating the lateral pressing plate is provided on the main body support mold.

[0011] Further, a positioning boss is provided on the main body support mold, and a concave hole matching the positioning boss is provided at the bottom of the lateral support mold.

[0012] Further, the hard pressing plate is made of a glass fiber prepreg cured molding material.

[0013] Further, the soft pressing plate is made of a low-rigidity material such as dry glass cloth and / or uncured rubber.

[0014] In a second aspect, a forming method for a "J"-type composite honeycomb sandwich structure is provided, including the steps of:

[0015] (1) Lay up the prepreg for making the lateral pressing plate on a layup platform, encapsulate the prepreg, and put it into a autoclave for curing and forming;

[0016] (2) Lay up the "1"-type layup group of the "J"-type composite honeycomb sandwich structure on the layup platform, and evacuate and compact it;

[0017] (3) Lay up the "C"-type layup group of the "J"-type composite honeycomb sandwich structure on the main body support mold;

[0018] (4) Install the lateral support mold on the main body support mold, fill the voids of the "J"-type composite honeycomb sandwich structure with unidirectional tapes, and evacuate and compact them;

[0019] (5) Place a honeycomb core on the "C"-type layup group of the "J"-type composite honeycomb sandwich structure, and then lay up the "Z"-type layup group of the "J"-type composite honeycomb sandwich structure;

[0020] (6) Remove the lateral support mold from the main body support mold, then remove the "1"-type layup group of the "J"-type composite honeycomb sandwich structure from the layup platform, and place it on the side of the "C"-type layup group of the "J"-type composite honeycomb sandwich structure for combination

[0021] (7) Install the lateral pressure plate onto the main body support mold, place it outside the "1"-type ply group of the "J"-type composite honeycomb sandwich structure, then place the combined upper pressure plate on the "Z"-type ply group of the "J"-type composite honeycomb sandwich structure, and after encapsulation, send it into the autoclave for curing and forming;

[0022] (8) During the demolding process after curing and forming, first remove the combined upper pressure plate from the "J"-type composite honeycomb sandwich structure, then remove the lateral pressure plate from the "J"-type composite honeycomb sandwich structure, and finally remove the "J"-type composite honeycomb sandwich structure from the main body support mold.

[0023] In summary, in the present invention, by laying the "C"-type ply group and the "1"-type ply group of the "J"-type composite honeycomb sandwich structure on the main body support mold and the layup platform with high stiffness and strength respectively, and laying the "Z"-type ply group, combining the "C"-type ply group and the "Z"-type ply group, filling with unidirectional tape and vacuum compaction on the combined body composed of the main body support mold and the lateral support mold, the dimensional accuracy and density of the prepreg layup are ensured. Not only is the layup operation simple and the mold positioning accurate, but also when encapsulating, lateral pressure plates, hard pressure plates, and soft pressure plates with different stiffnesses are used to press different areas of the part respectively, which is conducive to pressure transfer during the autoclave forming process, and the formed part has good internal quality and high dimensional accuracy. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments of the present invention. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of the "J"-type composite honeycomb sandwich structure.

[0026] Figure 2 It is a schematic structural diagram of a forming tooling (including a lateral support mold) for the "J"-type honeycomb sandwich structure.

[0027] Figure 3 It is a schematic structural diagram of a forming tooling (including a lateral pressure plate) for the "J"-type honeycomb sandwich structure.

[0028] In the figure: 10, "J"-type composite honeycomb sandwich structure "C"-type ply group; 11, "J"-type composite honeycomb sandwich structure "1"-type ply group; 12, "J"-type composite honeycomb sandwich structure "Z"-type ply group; 13, honeycomb core; 14, unidirectional tape; 20, main support mold; 21, lateral support mold; 22, hard pressing plate; 23, soft pressing plate; 24, lateral pressing plate; 30, limit card slot; 31, positioning boss; 32, concave hole. Specific implementation mode

[0029] The following further describes in detail the implementation mode of the present invention in conjunction with the drawings and embodiments. The following detailed description of the embodiments and the drawings are used to exemplarily illustrate the principle of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments, and covers any modifications, substitutions, and improvements of parts, components, and connection methods without departing from the spirit of the present invention.

[0030] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine the embodiments to detail the present application.

[0031] Please refer to Figure 1 , the "J"-type composite honeycomb sandwich structure includes a "J"-type composite honeycomb sandwich structure "C"-type ply group 10, a "J"-type composite honeycomb sandwich structure "1"-type ply group 11, a "J"-type composite honeycomb sandwich structure "Z"-type ply group 12, and a honeycomb core 13. Plate-core adhesive films are provided on both the upper surface and the lower surface of the honeycomb core 13.

[0032] How to simplify the layup and assembly operations and reduce the manufacturing cost while ensuring the forming dimensional accuracy and internal quality of the "J"-type composite honeycomb sandwich structure is a technically difficult problem. When manufacturing the "J"-type composite beam structure, if a combined metal mold is used and the layup is carried out on the metal mold blocks and then assembled, due to the large stiffness of the metal mold, the parts are prone to uneven pressure during the pressing process because of the mating clearance of the metal mold, resulting in the scrapping of the parts. During the autoclave forming process of the honeycomb sandwich structure, in order to prevent honeycomb slippage or collapse, a relatively low forming pressure is selected (generally ≤0.4 MPa), and due to the processing error of the honeycomb core 13, it is difficult to completely compact the skin prepreg on the honeycomb core 13. Therefore, the traditional metal mold supplemented with a single soft mold is also difficult to ensure the forming quality of the "J"-type composite honeycomb sandwich structure. However, if the vacuum bag molding is directly adopted, the "J"-type composite honeycomb sandwich structure will have a large deformation and it is difficult to control the external dimensions.

[0033] A forming tool for a "J"-type honeycomb sandwich structure according to the present invention solves the forming problem of the "J"-type composite honeycomb sandwich structure. It not only has simple layup operation and precise die positioning, but also uses pressing plates with different stiffnesses to press different regions of the part respectively, which is conducive to pressure transfer during autoclave forming. The formed part has good internal quality and high dimensional accuracy.

[0034] An embodiment of the present invention provides a forming tool for a "J"-type honeycomb sandwich structure. Please refer to Figure 2 , which includes a main body support mold 20, a side support mold 21, and a combined upper pressing plate. The upper surface of the main body support mold 20 matches the lower surface of the "C"-type ply group 10 of the "J"-type composite honeycomb sandwich structure. If the "C"-type ply group 10 of the "J"-type composite honeycomb sandwich structure is a closed-angle structure, the main body support core mold can also be appropriately designed in parts to ensure smooth demolding of the part. The main body support mold 20 is made of a material with high stiffness, strength, and heat resistance, such as Q235A structural steel, which ensures the dimensional accuracy and compactness of prepreg layup.

[0035] Among them, the side support mold 21 is detachably installed on one side of the main body support mold 20. The working surface of the side support mold 21 matches the outer surface of the "1"-type ply group 11 of the "J"-type composite honeycomb sandwich structure, ensuring the installation accuracy of the position of the "1"-type ply of the "J"-type composite honeycomb sandwich structure. The side support mold 21 is made of a material with high stiffness, strength, and heat resistance, such as Q235A structural steel, which ensures the dimensional accuracy and compactness of prepreg layup.

[0036] Among them, the combined upper pressing plate includes a hard pressing plate 22 and a soft pressing plate 23. The hard pressing plate 22 and the soft pressing plate 23 respectively correspond to the plate-plate area and the plate-core area of the upper surface of the "Z"-type ply group 12 of the "J"-type composite honeycomb sandwich structure. The plate-plate area corresponds to the overlapping area of the "C"-type ply group 10 and the "Z"-type ply group 12 of the "J"-type composite honeycomb sandwich structure, and the plate-core area corresponds to the area where the honeycomb core 13 is located.

[0037] As a preferred embodiment, please refer to Figure 3, further comprising a lateral pressing plate 24, the lateral pressing plate 24 is detachably mounted on one side of the main body support mold 20, and the working surface of the lateral pressing plate 24 matches the outer shape surface of the "1"-type ply group 11 of the "J"-type composite honeycomb sandwich structure. The lateral pressing plate 24 is made of a material with a thermal expansion coefficient similar to that of the composite material. After the "Z"-type ply group 12 of the "J"-type composite honeycomb sandwich structure is installed and positioned by the lateral support mold 21, the lateral pressing plate 24 is replaced to assist in forming the "1"-type ply group 11 of the "J"-type composite honeycomb sandwich structure. Since the thermal expansion coefficient of the lateral support mold 21 is different from that of the composite material, it will affect the forming of the product. Therefore, replacing it with the lateral pressing plate 24 has a better forming effect.

[0038] As a preferred embodiment, the lateral pressing plate 24 is made of the same prepreg curing molding material as the "J"-type composite honeycomb sandwich structure, ensuring that the thermal expansion coefficient of the lateral pressing plate 24 is similar to that of the composite material.

[0039] As a preferred embodiment, through experiments, the ply of the lateral pressing plate 24 is [+45 / -45 / 0 / 90]ns, where 2 ≤ n ≤ 4. Under this parameter, the thermal expansion coefficient of the lateral pressing plate 24 is closest to that of the composite material.

[0040] As a preferred embodiment, the length of the lateral pressing plate 24 of the lateral pressing plate 24 is L, and the width is H. The length of the "1"-type ply group 11 of the "J"-type composite honeycomb sandwich structure is L0, and the width is H0, where 40mm ≤ L - L0 ≤ 100mm, 0mm ≤ H - H0 ≤ 50mm, which can not only ensure that the lateral pressing plate 24 has high structural strength, but also meet the better coverage and support for the "1"-type ply of the "J"-type composite honeycomb sandwich structure.

[0041] As a preferred embodiment, a limit card slot 30 for partially accommodating the lateral pressing plate 24 is provided on the main body support mold 20. The limit card slot 30 matches the thickness of the lateral pressing plate 24, and the lateral pressing plate 24 is positioned by being inserted into the limit card slot 30.

[0042] As a preferred embodiment, a positioning boss 31 is provided on the main body support mold 20, and a concave hole 32 matching the positioning boss 31 is provided at the bottom of the lateral support mold 21. The lateral support mold 21 is positioned by the concave hole 32 being snapped onto the positioning boss 31.

[0043] As a preferred embodiment, the hard pressing plate 22 is made of a glass fiber prepreg cured molding material, i.e., a material system with a higher temperature resistance than the "J" type composite honeycomb sandwich structure prepreg, and the layup is [+45 / -45 / -45 / +45], which can effectively compact the plate-plate area on the upper surface of the "Z" type layup group 12 of the "J" type composite honeycomb sandwich structure.

[0044] As a preferred embodiment, the soft pressing plate 23 is made of a low stiffness material such as dry glass cloth and / or uncured rubber, which can effectively avoid damaging the plate-core area on the upper surface of the "Z" type layup group 12 of the "J" type composite honeycomb sandwich structure.

[0045] In a second aspect, a molding method for a "J" type composite honeycomb sandwich structure is provided. Please refer to Figures 1 to 3 , and it includes the steps:

[0046] (1) Lay up the prepreg for making the lateral pressing plate 24 on the layup platform, encapsulate the prepreg and put it into the autoclave for curing and molding;

[0047] (2) Lay up the "1" type layup group 11 of the "J" type composite honeycomb sandwich structure on the layup platform, and evacuate and compact it;

[0048] (3) Lay up the "C" type layup group 10 of the "J" type composite honeycomb sandwich structure on the main body support mold 20;

[0049] (4) Install the lateral support mold 21 on the main body support mold 20, fill the voids of the "J" type composite honeycomb sandwich structure with unidirectional tapes 14, and evacuate and compact them;

[0050] (5) Place the honeycomb core 13 on the "C" type layup group 10 of the "J" type composite honeycomb sandwich structure, and then lay up the "Z" type layup group 12 of the "J" type composite honeycomb sandwich structure;

[0051] (6) Remove the lateral support mold 21 from the main body support mold 20, and then remove the "1" type layup group 11 of the "J" type composite honeycomb sandwich structure from the layup platform, and place it on the side of the "C" type layup group 10 of the "J" type composite honeycomb sandwich structure for combination;

[0052] (7) Install the lateral pressing plate 24 on the main body support mold 20, place it outside the "1" type layup group 11 of the "J" type composite honeycomb sandwich structure, and then place the combined upper pressing plate on the "Z" type layup group 12 of the "J" type composite honeycomb sandwich structure, encapsulate it and send it into the autoclave for curing and molding;

[0053] (8) During the demolding process after curing and forming, first remove the combined upper pressing plate from the "J"-shaped composite honeycomb sandwich structure, then remove the lateral pressing plate 24 from the "J"-shaped composite honeycomb sandwich structure, and finally remove the "J"-shaped composite honeycomb sandwich structure from the main support mold 20.

[0054] In summary, in the present invention, the "C"-type ply group 10 and the "1"-type ply group of the "J"-shaped composite honeycomb sandwich structure are respectively laid on the main support mold 20 with high stiffness and strength and the laying platform. The laying of the "Z"-type ply group, the combination of the "C"-type ply group and the "Z"-type ply group, the filling of the unidirectional tape 14, and the vacuum compaction are carried out on the combined body composed of the main support mold 20 and the lateral support mold 21, which all ensure the dimensional accuracy and compactness of the prepreg laying. Not only is the laying operation simple and the mold positioning accurate, but also different stiffness lateral pressing plates 24, upper hard pressing plate 22, and upper soft pressing plate 23 are used to press different regions of the part during encapsulation, which is conducive to the pressure transfer during autoclave forming. The formed part has good internal quality and high dimensional accuracy.

[0055] It should be clear that each embodiment in this specification is described in a progressive manner. The same or similar parts between each embodiment can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments. For the method embodiments, the relevant parts can refer to the partial description of the device embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. And, for the sake of simplicity, the detailed description of known method technologies is omitted here.

[0056] The above are only the embodiments of the present application and do not limit the present application. For those skilled in the art, the present application can have various changes and modifications without departing from the scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A forming tooling for a "J"-type honeycomb sandwich structure, characterized in that, it includes: A main body support mold, the upper surface of the main body support mold matches the lower surface of the "C"-type ply group of the "J"-type composite honeycomb sandwich structure; A lateral support mold, the lateral support mold is detachably installed on one side of the main body support mold, and the working surface of the lateral support mold matches the outer surface of the "1"-type ply group of the "J"-type composite honeycomb sandwich structure; A combined upper pressing plate, the combined upper pressing plate includes a hard pressing plate and a soft pressing plate, the hard pressing plate and the soft pressing plate respectively correspond to the plate-plate area and the plate-core area of the upper surface of the "Z"-type ply group of the "J"-type composite honeycomb sandwich structure; the hard pressing plate is made of a cured molding material of glass fiber prepreg, and the soft pressing plate is made of a low-rigidity material of dry glass cloth and / or uncured rubber; A lateral pressing plate, the lateral pressing plate is detachably installed on one side of the main body support mold, and the working surface of the lateral pressing plate matches the outer surface of the "1"-type ply group of the "J"-type composite honeycomb sandwich structure.

2. A forming tooling for a "J"-type honeycomb sandwich structure according to claim 1, characterized in that, the lateral pressing plate is made of the same prepreg cured molding material as the "J"-type composite honeycomb sandwich structure.

3. A forming tooling for a "J"-type honeycomb sandwich structure according to claim 2, characterized in that, the ply of the lateral pressing plate is [+45 / -45 / 0 / 90]ns, where 2≤n≤4.

4. A forming tooling for a "J"-type honeycomb sandwich structure according to claim 1, characterized in that, the length of the lateral pressing plate of the lateral pressing plate is L, the width is H, the length of the "1"-type ply group of the "J"-type composite honeycomb sandwich structure is L0, and the width is H0, where 40mm≤L - L0≤100mm, 0mm≤H - H0≤50mm.

5. A forming tooling for a "J"-type honeycomb sandwich structure according to claim 1, characterized in that, a limit card slot for partially accommodating the lateral pressing plate is provided on the main body support mold.

6. A forming tooling for a "J"-type honeycomb sandwich structure according to claim 1, characterized in that, a positioning boss is provided on the main body support mold, and a concave hole matching the positioning boss is provided at the bottom of the lateral support mold.

7. A forming method for a "J"-type composite honeycomb sandwich structure, characterized in that, forming is carried out by using a forming tooling for a "J"-type honeycomb sandwich structure according to any one of claims 1-6, and the forming method includes the steps: (1) Lay the prepreg for making the lateral pressing plate on the layup platform, encapsulate the prepreg and put it into the autoclave for curing and forming; (2) Lay the "1"-type ply group of the "J"-type composite honeycomb sandwich structure on the layup platform, evacuate and compact; (3) Lay the "C"-type ply group of the "J"-type composite honeycomb sandwich structure on the main body support mold; (4) Install the lateral support mold on the main body support mold, fill the unidirectional tape in the void of the "J"-shaped composite honeycomb sandwich structure, and perform vacuum compaction; (5) Place the honeycomb core on the "C"-shaped ply group of the "J"-shaped composite honeycomb sandwich structure, and then perform the laying of the "Z"-shaped ply group of the "J"-shaped composite honeycomb sandwich structure; (6) Remove the lateral support mold from the main body support mold, and then remove the "1"-shaped ply group of the "J"-shaped composite honeycomb sandwich structure from the laying platform and place it on the side of the "C"-shaped ply group of the "J"-shaped composite honeycomb sandwich structure for combination; (7) Install the lateral pressing plate on the main body support mold, place it outside the "1"-shaped ply group of the "J"-shaped composite honeycomb sandwich structure, and then place the combined upper pressing plate on the "Z"-shaped ply group of the "J"-shaped composite honeycomb sandwich structure, and send it into the autoclave for curing and forming after encapsulation; (8) During the demolding process after curing and forming, first remove the combined upper pressing plate from the "J"-shaped composite honeycomb sandwich structure, then remove the lateral pressing plate from the "J"-shaped composite honeycomb sandwich structure, and finally remove the "J"-shaped composite honeycomb sandwich structure from the main body support mold.

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