Woven composite material flat plate forming device and woven composite material forming method

Abstract

The invention provides a braided composite material flat plate forming device and a braided composite material forming method.The braided composite material flat plate forming device comprises a core mold frame body and a bendable forming device which can be bent and flattened, and the bendable forming device can be installed in a notch of the core mold frame body in a bent mode during braiding forming; after being taken out, the woven composite material prefabricated body can be recovered to be in a straight mode, and a perforated woven composite material prefabricated body is obtained; the trepanning pre-embedded pin can be embedded on the bendable forming mechanism according to design requirements; the core mold frame body can be clamped to a traction mechanism of a knitting machine, and a multi-layer knitted prefabricated body is obtained. The invention further comprises a low-damage forming method of the woven composite flat plate with the open holes. The method has the advantages of being high in forming precision, small in prefabricated body structure damage, low in hole forming damage and capable of achieving integrated forming.

Description

Technical Field

[0001] The invention relates to the technical field of forming porous composite materials, and in particular to a woven composite material flat plate forming device and a woven composite material forming method using the forming device. Background Art

[0002] Composite materials have advantages such as good specific performance, strong designability and light weight, and are widely used in aerospace, rail transportation and other fields. Braided composite materials are composite materials that use a braided preform with an interwoven structure as a reinforcement. They have low manufacturing costs, high forming efficiency and excellent overall mechanical properties. The braided preform has poor structural retention performance. During the forming process of the braided composite flat plate such as stacking and transfer, in-plane shear deformation, yarn slippage, surface wrinkling and other phenomena are prone to occur, which seriously affects the forming quality and mechanical properties of the braided composite flat plate.

[0003] Mechanical connection is a major way to connect composite components. However, composite materials are difficult to process. Traditional machining and drilling procedures are complex, with low production efficiency and low forming stability. Due to the anisotropy of composite materials, mechanical drilling destroys the continuity of the internal fibers of the composite material and causes damage such as delamination, internal fragmentation, and burrs, which seriously affects the mechanical properties of the component opening area.

[0004] Therefore, a new technical solution is needed to solve the above problems. Summary of the invention

[0005] Purpose of the invention: In order to solve the above-mentioned problems, the present invention provides a woven composite material flat plate forming device to solve the technical problems of structural damage caused by the stacking and transfer of preforms in the traditional forming process and damage to the internal fibers of the composite material in the open hole area when manufacturing a woven composite material flat plate with openings.

[0006] The present invention also provides a method for forming a woven composite material using the woven composite material flat plate forming device, which also solves the above-mentioned problem.

[0007] To achieve the above-mentioned purpose, the technical solution of the braided composite material flat plate forming device provided by the present invention is:

[0008] A woven composite material flat plate forming device, comprising a core mold frame body and a bendable forming device; the core mold frame body is cylindrical, and a portion on the cylindrical surface of the core mold frame body is inwardly concavely provided with a notch with an arc-shaped cross section; the bendable forming device comprises a plurality of bent plates arranged side by side and a plurality of bendable thin plates; the cross section of each bent plate is an arc; after the side surfaces of every two adjacent bent plates are closely attached, the bottom surfaces of all the bent plates form a continuous long arc surface, and the curvature of the long arc surface is the same as the curvature of the bottom surface of the groove, and the length and width of the long arc surface are also the same as the length and width of the bottom surface of the groove; the upper surfaces of two adjacent bent plates span a bendable thin plate, and the top surfaces of the two adjacent bent plates are both concavely provided with mutually facing and communicating matching Groove, each bendable thin plate is arranged in the groove of the top surface of the two adjacent bent plates, and one side edge of the bendable thin plate is fixed to the inner side surface of one of the bent plate grooves, and the other side edge of the bendable thin plate is fixed to the inner side surface of the other bent plate groove; the thickness of the bendable thin plate is the same as the depth of the groove, so that after the side surfaces of every two adjacent bent plates are tightly attached, the top surfaces of all the bendable thin plates and the top surfaces of all the bent plates form a continuous arc surface; the upper surface of the bent plate and / or the bent plate are provided with a plurality of pre-embedded pins protruding upward through holes; when each bendable thin plate is flattened from the bent state, the top surface of each bendable thin plate and the top surface of the bent plate portion between each two adjacent bendable thin plates form a continuous plane.

[0009] Furthermore, the pre-embedded pins for the opening holes are all located on the outermost bent plates that are not in a row, and both sides of the top surfaces of these bent plates are provided with grooves for accommodating the flexible thin plates, and the middle position is a rib that separates the grooves on both sides, and the pre-embedded pins for the opening holes are installed on these ribs.

[0010] Furthermore, it also includes a curing plate (5), on which a plurality of holes corresponding to the pre-embedded pins in the openings are provided. When the curing plate (5) cooperates with the bendable forming device, the pre-embedded pins in the openings are inserted into the holes.

[0011] Furthermore, the two outermost bent plates in a row are provided with openings at both ends in the length direction, and fixing pins are provided in the openings. The slot of the core mold frame (3) is provided with blind holes corresponding to the openings, and the four corners of the curing plate (5) are also provided with mounting holes corresponding to the openings. When the bendable forming device is located in the slot, the fixing pins are installed downward in the opening and fixed in the blind holes. When the bendable forming device cooperates with the curing plate (5), the fixing pins extend upward in the opening and are installed and fixed in the mounting holes.

[0012] Furthermore, the bendable thin plate is made of rubber.

[0013] Furthermore, the bendable thin plate is made of shape memory alloy, and the initial state of the bendable thin plate is a flat plate state, and after being bent, it recovers to the initial flat plate state by heating.

[0014] Beneficial effects: The woven composite material flat plate forming device provided by the present invention provides a bendable and flattenable bendable forming device, so that during the weaving process of the preform, the woven composite material flat plate preform is always under the constraint of the bendable forming device, so that the woven composite material flat plate preform will not produce unexpected yarn slippage, in-plane shear deformation, wrinkling and other phenomena due to the steps of stacking, transferring, and carrying; at the same time, the embedded hole pins provided on the bendable forming device are always positioned at the pre-designed opening position of the woven composite material flat plate preform, and the continuity of the fibers of the woven composite material flat plate preform around the opening is retained during the forming process, and no shape and position movement will occur when the preform is transferred, thereby ensuring the accuracy of the opening forming.

[0015] The method for forming a woven composite material using the woven composite material flat plate forming device provided by the present invention adopts the following technical scheme, including the following steps:

[0016] S1, bend the bendable forming device and install it in the notch reserved in the core mold frame to form a complete curved surface to be woven;

[0017] S2, weaving the preform using a weaving machine; during the weaving process, the yarn bypasses the pre-embedded pins of the opening to form pre-embedded holes, and the weaving is continued until a preset number of layers of the preform is obtained;

[0018] S3, cutting out a preform on the bendable forming device and fixing the preform on the edges of the bendable forming device, and removing the bendable forming device in the bending mode from the core mold frame;

[0019] S4, restoring the bendable forming device to a flattened mode to obtain a woven composite material flat plate preform with openings.

[0020] Furthermore, a curing plate is provided, on which a plurality of holes corresponding one to one with the pre-embedded pins with openings are formed. When the curing plate cooperates with the bendable forming device, the pre-embedded pins with openings are inserted into the holes. After step S4, the flat plate preform of the woven composite material with openings and the pre-embedded pins with openings are transferred from the bendable forming device to the curing plate for preform curing.

[0021] Furthermore, the preform curing operation is to adopt epoxy resin vacuum bag curing molding technology to obtain a cured woven composite material flat plate.

[0022] Furthermore, the pre-embedded pins with the openings on the cured woven composite material plate are removed to obtain a woven composite material plate with openings.

[0023] Beneficial effects: In the woven composite material forming method provided by the present invention, a woven composite material flat plate preform with openings can be obtained through a woven composite material flat plate forming device. The forming process of the method is simple and the operability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the bendable forming mechanism in the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of the positioning block and the supporting block in the present invention;

[0026] Figure 3 It is a deformation schematic diagram of the bendable forming mechanism in the present invention;

[0027] Figure 4 It is a structural schematic diagram of the core mold frame body of the present invention;

[0028] Figure 5 It is a schematic diagram of the weaving forming of the preform in the present invention;

[0029] Figure 6 It is a schematic diagram of transferring a woven composite material flat plate preform with openings to a curing press plate in the present invention;

[0030] Figure 7 It is a schematic diagram of curing the flat vacuum bag of the woven composite material with openings in the present invention. DETAILED DESCRIPTION

[0031] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0032] Please combine Figure 1 and Figure 2 As shown, the present invention discloses a woven composite material flat plate forming device, including a core mold frame 3 and a bendable forming device; the core mold frame 3 is cylindrical, and a portion on the cylindrical surface of the core mold frame 3 is inwardly concave with a notch 31 with an arc-shaped cross section.

[0033] The bendable forming device comprises a plurality of bending plates arranged side by side and a plurality of bendable thin plates 13 . Figure 1 There are two types of bent plates, wherein the two outermost bent plates in a row of bent plates are labeled 11, and the other bent plates not in the outermost rows are labeled 12. Each bent plate has an arc cross section.

[0034] like Figure 3 As shown, the row of bent plates can be changed in a bent state or an extended state. After the sides of every two adjacent bent plates are closely attached, the bottom surfaces of all the bent plates form a continuous long arc surface and the curvature of the long arc surface is the same as the curvature of the bottom surface of the groove, and the length and width of the long arc surface are also the same as the length and width of the bottom surface of the groove, so that the bendable forming device can be adapted to be installed in the groove of the core mold frame 3 in the bent state to form an integral cylindrical shape with the core mold frame 3. The upper surfaces of the two adjacent bent plates in the bendable forming device span a bendable thin plate 13, and the top surfaces of the two adjacent bent plates are concavely provided with grooves 15 facing each other and communicating with each other. Each bendable thin plate 13 is arranged in the groove 15 on the top surfaces of the two adjacent bent plates, and one side edge of the bendable thin plate 13 is fixed to the inner side surface of one of the bend plate grooves, and the other side edge of the bendable thin plate 13 is fixed to the inner side surface of the other bend plate groove, and the fixing method can be adhesive fixing. The thickness of the bendable sheet 13 is the same as the depth of the groove 15, so that when the sides of every two adjacent bent plates are tightly attached, the top surfaces of all the bendable sheets 13 and the top surfaces of all the bent plates form a continuous arc surface. At the same time, the bendable sheets 13 also connect the two adjacent bent plates together, so that the entire bendable forming device is connected into a whole through these bendable sheets 13, and when each bendable sheet 13 is flattened from the bent state, the top surface of each bendable sheet 13 and the top surface of the bent plate portion between each adjacent bendable sheet 13 form a continuous plane. In the bendable forming device, a plurality of pre-embedded open-hole pins 2 protruding upward are provided on the upper surface of the bent plate and / or the bent plate 13. In the drawings provided in this embodiment, the pre-embedded open-hole pins 2 are provided on the bent plate 12, and the pre-embedded open-hole pins 2 are all located on the bent plate that is not on the outermost side in a row, that is, Figure 1 On the bent plates 12 in the middle, grooves 15 for accommodating the bendable thin plates are provided on both sides of the top surface of these bent plates 12, and the middle position is a rib 16 separating the grooves 15 on both sides. The pre-embedded pins 2 with holes are installed on these ribs 16, and the ribs 16 are provided with blind holes 21 for accommodating the pre-embedded pins 2 with holes. The positions of the pre-embedded pins 2 with holes can be embedded in the preset positions on the bendable forming device according to the design requirements. The two outermost bent plates 11 in a row are provided with openings 17 at both ends in the length direction, and the openings 17 are provided with fixing pins 14; Figure 4 As shown, a blind hole 32 corresponding to the opening 17 is provided in the slot 31 of the core mold frame 3. When the bendable forming device is located in the slot 31, the fixing pin 14 is installed downward in the opening 17 and fixed in the blind hole 32 to fix the bendable forming device in the slot 31.

[0035] In this embodiment, the bendable sheet 13 may be made of rubber or shape memory alloy. When the bendable sheet 13 is made of rubber, the bending or flattening of the bendable sheet is achieved by passive operation. When the bendable sheet 13 is made of shape memory alloy, the initial state of the bendable sheet 13 is a flat plate, and after bending, it is restored to the initial flat plate state by heating, that is, the flattening of the bendable sheet 13 can be actively achieved by heating.

[0036] In order to enable the braided composite material preform obtained by braiding in the bendable forming device to be removed for subsequent curing operations, a curing plate 5 is further provided. The curing plate 5 is provided with a plurality of holes 51 corresponding to the pre-embedded pins 2 in the openings on the bent plate 12. When the curing plate 5 is matched with the bendable forming device, the pre-embedded pins 2 in the openings are inserted into the holes 51. The four corners of the curing plate 5 are also provided with mounting holes 52 corresponding to the openings 17 of the bent plate 11. When the bendable forming device is matched with the curing plate 5, the fixing pins 14 extend upward in the openings 17 and are fixed in the mounting holes 52.

[0037] The method for forming a woven composite material using the woven composite material flat plate forming device is as follows:

[0038] S1, bend the bendable forming device and install it in the notch 31 reserved in the core mold frame body 3 to form a complete curved surface to be woven;

[0039] S2, such as Figure 5 As shown, a rotary braiding machine is used to braid the preform; during the braiding process, the yarn bypasses the pre-embedded pin 2 with an opening to form a pre-embedded hole, and the braiding is continued until the preset number of layers of the preform is obtained;

[0040] S3, cutting out a preform on the bendable forming device and fixing the preform on the edges of the bendable forming device, and removing the bendable forming device in the bending mode from the core mold frame body 3;

[0041] S4, restore the bendable forming device to a flattened mode to obtain a woven composite material flat plate preform with openings. The bendable forming mechanism will drive the preform to flatten while restoring to a straight mode. Since the preform is fixed on all sides, it can ensure that the preform is evenly flattened. At this time, the openings have been formed on the woven composite material flat plate preform.

[0042] Furthermore, after step S4, the following steps may also be included:

[0043] S5, then transfer the woven composite material flat plate preform with openings and the pre-embedded pins 2 with openings from the bendable forming device to the curing press plate 5 for preform curing operation, such as Figure 5 As shown. Figure 6As shown, the preform curing operation is to use epoxy resin vacuum bag curing molding technology to obtain a cured woven composite material flat plate. Then, the hole embedded pins 2 on the cured woven composite material flat plate are removed to obtain a woven composite material flat plate with holes.

Claims

1. A woven composite material flat plate forming device, characterized in that: It includes a core mold frame and a bendable forming device; the core mold frame is cylindrical, and a portion on the cylindrical surface of the core mold frame is inwardly concavely provided with a notch with an arc-shaped cross section; The bendable forming device comprises a plurality of bent plates and a plurality of bendable thin plates arranged side by side; the cross section of each bent plate is arc-shaped; after the side surfaces of every two adjacent bent plates are in close contact, the bottom surfaces of all the bent plates form a continuous long arc surface, and the curvature of the long arc surface is the same as the curvature of the bottom surface of the groove, and the length and width of the long arc surface are also the same as the length and width of the bottom surface of the groove; the upper surfaces of two adjacent bent plates span a bendable thin plate, and the top surfaces of two adjacent bent plates are concavely provided with grooves facing each other and communicating with each other, each bendable thin plate is arranged in the groove of the top surfaces of the two adjacent bent plates, and one side edge of the bendable thin plate is fixed to the inner side surface of one of the grooves of the bent plates, and the other side edge of the bendable thin plate is fixed to the inner side surface of the groove of the other bent plate; the thickness of the bendable thin plate is the same as the depth of the groove, so that after the side surfaces of every two adjacent bent plates are in close contact, the top surfaces of all the bendable thin plates and the top surfaces of all the bent plates form a continuous arc surface; the upper surface of the bent plate and / or the bent thin plate are provided with a plurality of pre-embedded pins with openings protruding upward; When each bendable thin plate is flattened from the bent state, the top surface of each bendable thin plate and the top surface of the bent plate portion between two adjacent bendable thin plates form a continuous plane.

2. The woven composite material flat plate forming device according to claim 1, characterized in that: The hole-embedded pins are all located on the outermost bent plates that are not in a row. Both sides of the top surfaces of these bent plates are provided with grooves for accommodating the bendable thin plates, and the middle position is a rib that separates the grooves on both sides, and the hole-embedded pins are installed on these ribs.

3. The braided composite material flat plate forming device according to claim 2, characterized in that: It also includes a curing plate (5) on which a plurality of holes corresponding to the pre-embedded pins in the openings are arranged. When the curing plate (5) cooperates with the bendable forming device, the pre-embedded pins in the openings are inserted into the holes.

4. The braided composite material flat plate forming device according to claim 3, characterized in that: The two outermost bent plates in a row are provided with openings at both ends in the length direction, and fixing pins are provided in the openings. The slot of the core mold frame (3) is provided with blind holes corresponding to the openings, and the four corners of the curing plate (5) are also provided with mounting holes corresponding to the openings. When the bendable forming device is located in the slot, the fixing pins are installed downward in the opening and fixed in the blind holes. When the bendable forming device cooperates with the curing plate (5), the fixing pins extend upward in the opening and are installed and fixed in the mounting holes.

5. The braided composite material flat plate forming device according to claim 1, characterized in that: The bendable thin plate is made of rubber.

6. The braided composite material flat plate forming device according to claim 1, characterized in that: The bendable thin plate is made of shape memory alloy. The initial state of the bendable thin plate is a flat plate state, and after being bent, it is restored to the initial flat plate state by heating.

7. A method for forming a woven composite material using the woven composite material flat plate forming device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, bend the bendable forming device and install it in the notch reserved in the core mold frame to form a complete curved surface to be woven; S2, weaving the preform using a weaving machine; during the weaving process, the yarn bypasses the pre-embedded pins of the opening to form pre-embedded holes, and the weaving is continued until a preset number of layers of the preform is obtained; S3, cutting out a preform on the bendable forming device and fixing the preform on the edges of the bendable forming device, and removing the bendable forming device in the bending mode from the core mold frame; S4, restoring the bendable forming device to a flattened mode to obtain a woven composite material flat plate preform with openings.

8. The method for forming a braided composite material according to claim 7, characterized in that: A curing press plate is provided, on which a plurality of holes corresponding to the pre-embedded pins with holes are provided. When the curing press plate (5) cooperates with the bendable forming device, the pre-embedded pins with holes are inserted into the holes. After step S4, the woven composite material flat plate preform with holes and the pre-embedded pins with holes are transferred from the bendable forming device to the curing press plate to perform the preform curing operation.

9. The method for forming a braided composite material according to claim 8, characterized in that: The preform curing operation is to adopt epoxy resin vacuum bag curing molding technology to obtain a cured woven composite material flat plate.

10. The method for forming a braided composite material according to claim 9, characterized in that: The pre-embedded pins with the openings on the cured woven composite material plate are removed to obtain a woven composite material plate with openings.

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