Method of forming a structure with curvature

Abstract

The application provides a forming method of a structure with curvature, comprising the following steps: providing a mold, the mold comprising a main body part, a first auxiliary plate and a second auxiliary plate, the first auxiliary plate and the second auxiliary plate being respectively located on the opposite sides of the main body part; the main body part comprising a web, a first connecting plate and a second connecting plate, the first connecting plate and the second connecting plate being respectively located on the opposite sides of the web; providing a prepreg stack, attaching the prepreg stack to the first auxiliary plate, and then bending the prepreg stack towards the web until the prepreg stack is attached to the web; bending the prepreg stack towards the second auxiliary plate until the prepreg stack is attached to the second auxiliary plate. The forming method prevents the accumulation of fibers in the prepreg stack during the forming process, thereby avoiding the formation of wrinkles in the structure with curvature.

Description

Technical Field

[0001] This invention relates to the field of composite material processing, and more particularly to a molding method for a curved structure. Background Technology

[0002] Automated tape and fiber placement technologies for composite materials are becoming increasingly mature and are widely used in the production and manufacturing processes of composite materials. The combination of composite material preforming technology with tape or fiber placement technology has become an important means of manufacturing slender parts such as L-shaped, C-shaped, and Z-shaped components. Composite material preforming technology can reduce a significant amount of manual labor and can be used to achieve automated industrial production.

[0003] Composite material preforming is a multi-physics coupling, large deformation, and anisotropic process. For parts with complex curved structures, wrinkles easily form in the prepreg during the molding process because manual cutting of non-spreadable areas is not possible. Once wrinkles form, they are difficult to eliminate by other means, eventually leading to layup wrinkles after the composite material cures. Wrinkles are unacceptable in composite parts. Therefore, it is necessary to control the deformation process of the composite sheet during preforming to eliminate wrinkles generated during the preforming process of composite parts.

[0004] Therefore, it is necessary to provide a novel molding method for curved structures to solve the aforementioned problems existing in the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a molding method with a curved structure to prevent fiber accumulation on the outer side of the prepreg stack during the molding process, thereby avoiding wrinkle defects in the formed curved structure.

[0006] To achieve the above objectives, the molding method for the curved structure of the present invention includes the following steps:

[0007] S0: A mold is provided, the mold including a main body, a first auxiliary plate and a second auxiliary plate, the first auxiliary plate and the second auxiliary plate are both rectangular plates, and the first auxiliary plate and the second auxiliary plate are respectively located on opposite sides of the main body;

[0008] The main body includes a web, a first connecting plate, and a second connecting plate. The web is a rectangular plate, and the first and second connecting plates are both arc-shaped plates. The first and second connecting plates are located on opposite sides of the web. The long side of one side of the web is the same length as the long side of one side of the first connecting plate and they are connected, so that the outer side of the web is connected to the outer side of the first connecting plate. The long side of the other side of the web is the same length as the long side of one side of the second connecting plate and they are connected, so that the outer side of the web is connected to the outer side of the second connecting plate.

[0009] The long side of the other side of the first connecting plate is the same length as the long side of one side of the first auxiliary plate and is connected to it, so that the outer side of the first connecting plate is connected to the outer side of the first auxiliary plate. The long side of the other side of the second connecting plate is connected to the long side of one side of the second auxiliary plate, so that the outer side of the second connecting plate is connected to the outer side of the second auxiliary plate.

[0010] S1: Provide a prepreg stack, the prepreg stack including opposite sides, attach one side of the prepreg stack to the first auxiliary plate, and then bend the other side of the prepreg stack toward the web plate until the prepreg stack is attached to the web plate, so that the prepreg stack is attached to the first connecting plate.

[0011] S2: Bend the other side of the prepreg stack toward the second auxiliary plate until the prepreg stack is in contact with the second auxiliary plate, so that the prepreg stack is in contact with the second connecting plate.

[0012] The beneficial effect of the molding method with a curved structure of the present invention is that: the other side of the prepreg laminate is bent towards the web until the prepreg laminate is in contact with the web, so that the prepreg laminate is in contact with the first connecting plate. During the bending process of the prepreg laminate in contact with the first connecting plate, the radius of the outer side of the prepreg laminate decreases. The fiber layup on the outer side of the prepreg laminate is always pulling the fibers towards the side of the prepreg laminate with the smaller radius. The prepreg laminate as a whole is not compressed. The non-arc fibers on the outer side of the prepreg laminate are stretched, and the arc fibers on the outer side of the prepreg laminate do not buckle. Therefore, during the molding process, there is no material accumulation in the curved portion on the outer side of the prepreg laminate, thereby avoiding the outer side of the prepreg laminate. The formation of wrinkles is prevented by bending the other side of the prepreg stack towards the second auxiliary plate until the prepreg stack is in contact with the second auxiliary plate, so that the prepreg stack is in contact with the second connecting plate. During the bending process of the prepreg stack in contact with the second connecting plate, the radius of the outer side of the prepreg stack decreases. The fiber layup on the outer side of the prepreg stack is always pulling the fibers towards the side of the prepreg stack with the smaller radius. The prepreg stack as a whole is not compressed. The non-arc fibers on the outer side of the prepreg stack are stretched. The arc fibers on the outer side of the prepreg stack will not bend. Therefore, during the molding process, there will be no material accumulation in the bent part on the outer side of the prepreg stack, thereby avoiding the formation of wrinkles on the outer side of the prepreg stack.

[0013] Optionally, in step S1, the step of attaching one side of the prepreg stack to the first auxiliary plate includes: attaching one side of the prepreg stack to the long side of the outer side of the first auxiliary plate away from the first connecting plate, so as to position the prepreg stack on the first auxiliary plate.

[0014] Optionally, during the bonding process between the prepreg laminate and the first auxiliary plate, the fiber 0° direction of the prepreg laminate must be parallel to the long side of the first auxiliary plate.

[0015] Optionally, between steps S0 and S1, step S01 is also included: forming the prepreg laminate by manual laying, automatic tape laying, or automatic filament laying.

[0016] Optionally, the reinforcement of the prepreg includes carbon fiber, glass fiber or aramid fiber, and its matrix resin includes epoxy resin, polyimide resin or phenolic resin.

[0017] Optionally, in step S1, the materials of the web, the first auxiliary plate, the second auxiliary plate, the first connecting plate, and the second connecting plate are all metal, wood, or resin polymer.

[0018] Optionally, steps S1 to S2 are all performed in a preforming device, which includes either a thermal insulation film preforming device or a thermal molding preforming device.

[0019] Optionally, in step S0, the web plate is connected to the first connecting plate, the web plate to the second connecting plate, the first connecting plate to the first auxiliary plate, and the second connecting plate to the second auxiliary plate via a fixing part.

[0020] Optionally, the fixing parts all include bolts and nuts.

[0021] Optionally, the thickness of the prepreg laminate ranges from 1 mm to 10 mm. Attached Figure Description

[0022] Figure 1 This is an overall structural diagram of the C-shaped mold of the present invention;

[0023] Figure 2 This is a schematic diagram of the prepreg stack of the present invention being bonded to the C-shaped mold;

[0024] Figure 3 This is a schematic diagram of the prepreg laminate of the present invention being bent toward the web;

[0025] Figure 4 This is an overall view of the L-shaped preform in Embodiment 1 of the present invention;

[0026] Figure 5 This is a schematic diagram of the prepreg stack of the present invention bending towards the second auxiliary plate;

[0027] Figure 6 This is an overall view of the C-shaped preform in Embodiment 2 of the present invention;

[0028] Figure 7 This is an overall structural diagram of the Z-shaped mold of the present invention;

[0029] Figure 8 This is a schematic diagram of the prepreg laminate of the present invention being bent toward the third auxiliary plate;

[0030] Figure 9 This is an overall view of the Z-shaped preform in Embodiment 3 of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0032] To address the problems existing in the prior art, embodiments of the present invention provide a molding method for a curved structure, comprising the following steps:

[0033] S0: A mold is provided, the mold including a main body, a first auxiliary plate and a second auxiliary plate, the first auxiliary plate and the second auxiliary plate are both rectangular plates, and the first auxiliary plate and the second auxiliary plate are respectively located on opposite sides of the main body;

[0034] The main body includes a web, a first connecting plate, and a second connecting plate. The web is a rectangular plate, and the first and second connecting plates are both arc-shaped plates. The first and second connecting plates are located on opposite sides of the web. The long side of one side of the web is the same length as the long side of one side of the first connecting plate and they are connected, so that the outer side of the web is connected to the outer side of the first connecting plate. The long side of the other side of the web is the same length as the long side of one side of the second connecting plate and they are connected, so that the outer side of the web is connected to the outer side of the second connecting plate.

[0035] The long side of the other side of the first connecting plate is the same length as the long side of one side of the first auxiliary plate and is connected to it, so that the outer side of the first connecting plate is connected to the outer side of the first auxiliary plate. The long side of the other side of the second connecting plate is connected to the long side of one side of the second auxiliary plate, so that the outer side of the second connecting plate is connected to the outer side of the second auxiliary plate.

[0036] S1: The prepreg stack includes two opposite sides. One side of the prepreg stack is attached to the first auxiliary plate, and then the other side of the prepreg stack is bent toward the web plate until the prepreg stack is attached to the web plate, so that the prepreg stack is attached to the first connecting plate.

[0037] S2: Bend the other side of the prepreg stack toward the second auxiliary plate until the prepreg stack is in contact with the second auxiliary plate, so that the prepreg stack is in contact with the second connecting plate.

[0038] The advantages of the molding method with a curved structure according to the present invention are as follows: the other side of the prepreg laminate is bent towards the web until the prepreg laminate is in contact with the web, so that the prepreg laminate is in contact with the first connecting plate. During the bending process of the prepreg laminate in contact with the first connecting plate, the radius of the outer side of the prepreg laminate decreases. The fiber layup of the prepreg laminate is always pulling the fibers towards the side where the radius of the prepreg laminate decreases. The prepreg laminate as a whole is not compressed, and the non-arc fibers on the outer side of the prepreg laminate are stretched. The arc fibers on the outer side of the prepreg laminate do not buckle. Therefore, during the molding process, there is no material accumulation on the curved portion on the outer side of the prepreg laminate, thereby avoiding the outer side of the prepreg laminate... The formation of wrinkles: The other side of the prepreg laminate is bent toward the second auxiliary plate until the prepreg laminate is in contact with the second auxiliary plate, so that the prepreg laminate is in contact with the second connecting plate. During the bending process of the prepreg laminate in contact with the second connecting plate, the radius of the outer side of the prepreg laminate decreases. The fiber layup of the prepreg laminate is always pulling the fibers toward the side of the prepreg laminate with the smaller radius. The prepreg laminate as a whole is not compressed. The non-arc fibers on the outer side of the prepreg laminate are stretched. The arc fibers on the outer side of the prepreg laminate will not bend. Therefore, during the molding process, there will be no material accumulation in the bent part on the outer side of the prepreg laminate, thereby avoiding the formation of wrinkles on the outer side of the prepreg laminate.

[0039] In some embodiments, step S1, the step of attaching one side of the prepreg stack to the first auxiliary plate includes: attaching one side of the prepreg stack to the long side of the outer side of the first auxiliary plate away from the first connecting plate, so as to position the prepreg stack on the first auxiliary plate.

[0040] In some embodiments, the prepreg stack needs to satisfy the requirement that the fiber 0° direction of the prepreg stack is parallel to the long side of the first auxiliary plate during the bonding process with the first auxiliary plate.

[0041] In some embodiments, between steps S0 and S1, there is also a step S01: forming the prepreg laminate by manual laying, automatic tape laying or automatic filament laying.

[0042] In some embodiments, the reinforcement of the prepreg includes carbon fiber, glass fiber or aramid fiber, and its matrix resin includes epoxy resin, polyimide resin or phenolic resin.

[0043] In some embodiments, in step S1, the web plate, the first auxiliary plate, the second auxiliary plate, the first connecting plate, and the second connecting plate are all made of any one of metal, wood, or resin polymer.

[0044] In some embodiments, steps S1 to S2 are all performed in a preforming device, which includes either a thermal insulation film preforming device or a thermal molding preforming device.

[0045] In some embodiments, in step S0, the web plate is connected to the first connecting plate, the web plate to the second connecting plate, the first connecting plate to the first auxiliary plate, and the second connecting plate to the second auxiliary plate by a fixing part.

[0046] In some embodiments, the fixing part includes a bolt and a nut.

[0047] In some embodiments, the fixing part includes a first fixing component, a second fixing component, a third fixing component, a fourth fixing component, a fifth fixing component, and a sixth fixing component.

[0048] In some embodiments, the thickness of the prepreg laminate ranges from 1 mm to 10 mm.

[0049] Figure 4 This is an overall view of the L-shaped preform in Embodiment 1 of the present invention; Figure 6 This is an overall view of the C-shaped preform in Embodiment 2 of the present invention; Figure 9 This is an overall view of the Z-shaped preform in Embodiment 3 of the present invention.

[0050] Reference Figure 4 , Figure 6 and Figure 9 As shown, this invention proposes a molding method for a curved structure. The curved structure, made of composite material, includes a main body and flanges bent at both ends of the main body. Please refer to... Figures 1 to 3As shown, the preform with curved structure includes an L-shaped preform 4, a C-shaped preform 5, and a Z-shaped preform 6. The L-shaped preform 4 includes a first body 41 and a first flange 42 bent to the left side of the first body 41, and also includes an inner diameter R1 and an outer diameter R2 located on the left side. Both the inner diameter R1 and the outer diameter R2 are rounded, and the inner diameter R1 is smaller than the outer diameter R2. The C-shaped preform 5 includes a second body 51 and a second flange 52 and a third flange 53 bent to opposite sides of the second body 51. The C-shaped preform 5 also includes an inner diameter R3 and an outer flange 53 located on the left side. The Z-shaped preform 6 includes a third body 61 and a fourth flange 62 and a fifth flange 63 bent on opposite sides of the third body 61. The Z-shaped preform 6 also includes an inner diameter R7 and an outer diameter R8 on the left and a right side, with rounded corners on both sides. The inner diameter R7 is smaller than the outer diameter R8, and the inner diameter R9 is smaller than the outer diameter R10.

[0051] In some embodiments, the mold includes either a C-shaped mold or a Z-shaped mold.

[0052] Example 1

[0053] Figure 1 This is an overall structural diagram of the C-shaped mold of the present invention.

[0054] Reference Figure 1As shown, the C-shaped mold includes a main body 11, a first auxiliary plate 12, and a second auxiliary plate 13. The main body 11 includes a first connecting plate 111, a web 112, and a second connecting plate 113. Both the first connecting plate 111 and the second connecting plate 113 are arc-shaped plates, each including a first arcuate surface 1141 and a second arcuate surface 1142. The radius of the first arcuate surface 1141 is larger than the radius of the second arcuate surface 1142. The web 112 is a rectangular plate, including a first side 1121 and a second side 1122. The first side 1121 and the second side 1122 are located on opposite sides of the web 112 and each includes two long sides of the web 112. The first connecting plate 111 and the second connecting plate 113 are located on opposite sides of the web 112. The long side of the first connecting plate 111 closest to the web 112 is connected to the first connecting plate 112. The long sides of one side 1121 correspond one-to-one with each other and have the same length, and are connected to the long side of the first side 1121, so that the first arc-shaped curved surface 1141 of the first connecting plate 111 is connected to the outer side of the web 112 to form a smooth curved surface. The web 112 is connected to the first connecting plate 111 by a first fixing component, which can be a bolt and nut, or a buckle or other structure. The long side of the second connecting plate 113 near the web 112 corresponds one-to-one with the long side of the second side 1122 and has the same length, and is connected to the long side of the second side 1122, so that the first arc-shaped curved surface 1141 of the second connecting plate 113 is connected to the outer side of the web 112 to form a smooth curved surface. The web 112 is connected to the second connecting plate 113 by a second fixing component, which can be a bolt and nut, or a buckle or other structure.

[0055] Both the first auxiliary plate 12 and the second auxiliary plate 13 are rectangular plates. The first auxiliary plate 12 and the web plate 112 are located on opposite sides of the first connecting plate 111. The long side of the first auxiliary plate 12 closest to the first connecting plate 111 corresponds one-to-one with the long side of the first connecting plate 111 closest to the first auxiliary plate 12 and has the same length. The long side of the first connecting plate 111 closest to the first auxiliary plate 12 is connected to the long side of the first connecting plate 111 closest to the first auxiliary plate 12, so that the outer side of the first auxiliary plate 12 is connected to the first arcuate surface 1141 of the first connecting plate 111 to form a smooth curved surface. The first connecting plate 111 and the first auxiliary plate 12 are connected by a third fixing component, which can be a bolt and a screw. The mother plate can also be a snap-fit ​​or other structure; the second auxiliary plate 13 and the web plate 112 are located on opposite sides of the second connecting plate 113. The long side of the second auxiliary plate 13 near the second connecting plate 113 corresponds one-to-one with the long side of the second connecting plate 113 near the second auxiliary plate 13 and has the same length. The long side of the second connecting plate 113 near the second auxiliary plate 13 is connected to the long side of the second connecting plate 113 near the second auxiliary plate 13, so that the outer side of the second auxiliary plate 13 is connected to the first arc-shaped curved surface 1141 of the second connecting plate 113 to form a smooth curved surface. The second connecting plate 113 and the second auxiliary plate 13 are connected by a fourth fixing component. The fourth fixing component can be a bolt and nut, or a snap-fit ​​or other structure.

[0056] Figure 2 This is a schematic diagram of the prepreg stack of the present invention being bonded to the C-shaped mold; Figure 3 This is a schematic diagram of the prepreg laminate of the present invention being bent toward the web.

[0057] Reference Figures 2 to 4 The molding method for the L-shaped preform 4 includes the following steps:

[0058] S0: Provide the C-shaped mold;

[0059] S1: A prepreg stack 3 is provided, the prepreg stack including a first side 31 and a second side 32 opposite to each other. The prepreg stack 3 also includes a prepreg stack outer side 33 and a prepreg stack inner side 34. The first side 31 is attached to the long side of the first auxiliary plate 12 of the mold on the side away from the first connecting plate 111. Then, the prepreg stack inner side 34 is moved towards the outside of the first auxiliary plate 12 until the prepreg stack inner side 34 is attached to the first auxiliary plate 12. During the attachment process, the fibers of the prepreg stack outer side 33 are stretched. The length of the prepreg stack 3 attached to the first auxiliary plate 12 is pre-designed to form the first flange 42. The second side 32 is bent towards the web plate 112 along direction A until the prepreg stack inner side 34 is attached to the web plate 112. The fibers of the prepreg stack outer side 33 are stretched so that the prepreg stack 3 is attached to the first connecting plate 111. The first arc-shaped surface 1141 of the first connecting plate 111 is attached. During the bending process of the outer side 33 of the prepreg laminate attached to the first arc-shaped surface 1141 of the first connecting plate 111, the radius of the prepreg laminate 3 decreases. The fiber layup of the prepreg laminate 3 is always pulling the fibers towards the side where the radius of the prepreg laminate 3 decreases. The prepreg laminate 3 as a whole is not compressed. The non-arc fibers of the outer side 33 of the prepreg laminate are stretched. The arc fibers of the outer side 33 of the prepreg laminate do not need to generate a certain buckling to release the compressive stress. The outer side 33 of the prepreg laminate will not accumulate material, so no wrinkle defects will be generated. Then, the C-shaped mold supporting the prepreg laminate 3 is placed in the preforming equipment for heat insulation or heat molding to obtain the L-shaped preform 4. In this process, the C-shaped mold is used to form the inner diameter R1 on the left side of the L-shaped preform 4. R1 is consistent with the radius of the first arc-shaped surface 1141 of the first connecting plate 111.

[0060] Example 2

[0061] Figure 5 This is a schematic diagram of the prepreg stack of the present invention bending towards the second auxiliary plate.

[0062] Reference Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, the molding method for the C-shaped preform 5 includes the following steps:

[0063] S0: Provide the C-shaped mold;

[0064] S1: A prepreg laminate 3 is provided, the prepreg laminate including a first side 31 and a second side 32 opposite to each other. The prepreg laminate 3 also includes a prepreg laminate outer side 33 and a prepreg laminate inner side 34. One side of the first side 31 is attached to the long side of the outer side of the first auxiliary plate 12 of the mold away from the first connecting plate 111. Then, the prepreg laminate inner side 34 is brought closer to the first auxiliary plate 12 until the prepreg laminate inner side 34 is attached to the first auxiliary plate 12. During the attachment process, the fibers of the prepreg laminate outer side 33 are stretched. The length of the prepreg laminate 3 attached to the first auxiliary plate 12 is pre-designed to form the second flange 52. The second side 32 is bent towards the web plate 112 along direction A until the prepreg laminate inner side 34 is attached to the web plate 112. The fibers of the prepreg laminate outer side 33 are stretched so that the prepreg laminate 3 is attached to the first connecting plate. The first arc-shaped surface 1141 of the first connecting plate 111 is attached. During the bending process of the outer side 33 of the prepreg laminate attached to the first arc-shaped surface 1141 of the first connecting plate 111, the radius of the prepreg laminate 3 decreases. The fiber layup of the prepreg laminate 3 is always pulling the fibers towards the side where the radius of the prepreg laminate 3 decreases. The prepreg laminate 3 as a whole is not compressed. The non-arc fibers of the outer side 33 of the prepreg laminate are stretched. The arc fibers of the outer side 33 of the prepreg laminate do not need to generate a certain buckling to release the compressive stress. The outer side 33 of the prepreg laminate will not accumulate material, so no wrinkle defects will be generated. Then, the C-shaped mold supporting the prepreg laminate 3 is placed in the preforming equipment for heat insulation or hot molding to obtain the first intermediate body. In this process, the C-shaped mold is used to form the inner diameter R3 on the left side of the first intermediate body. R3 is consistent with the radius of the first arc-shaped surface 1141 of the first connecting plate 111.

[0065] S2: Bend the second side 32 along direction B toward the second auxiliary plate 13 until the inner side 34 of the prepreg laminate is bonded to the second auxiliary plate 13. During the bonding process, the fibers of the outer side 33 of the prepreg laminate are stretched so that the prepreg laminate 3 is bonded to the first arcuate surface 1141 of the second connecting plate 113. The length of the prepreg laminate 3 bonded to the second auxiliary plate 13 is pre-designed to form the third edge strip 53. The radius of the outer side 33 of the prepreg laminate decreases during the bending process of bonding to the first arcuate surface 1141 of the second connecting plate 113. The fiber layup of the prepreg laminate 3 is always oriented toward the prepreg laminate 3. The side with a smaller radius is pulling the fibers, and the prepreg stack 3 as a whole is not compressed. The non-arc fibers on the outer side 33 of the prepreg stack are stretched, and the arc fibers on the outer side 33 of the prepreg stack do not need to produce a certain amount of buckling to release the compressive stress. The outer side 33 of the prepreg stack will not accumulate material, thus avoiding wrinkle defects. Subsequently, the C-shaped mold supporting the prepreg stack 3 is placed in the preforming equipment for heat insulation or heat molding to obtain the C-shaped preform. In this process, the C-shaped mold is used to form the inner diameter R5 on the right side of the C-shaped preform 5. R5 is consistent with the radius of the first arc surface 1141 of the second connecting plate 113.

[0066] Example 3

[0067] Figure 7 This is an overall structural diagram of the Z-shaped mold of the present invention.

[0068] Reference Figure 7 As shown, the Z-shaped mold includes a main structure 21 on the left, a third connecting plate 22 on the right, and a third auxiliary plate 23. The third connecting plate 22 is an arc-shaped plate, including a third arc-shaped surface 221 and a fourth arc-shaped surface 222. The radius of the third arc-shaped surface 221 is larger than the radius of the fourth arc-shaped surface 222. The long side of the third connecting plate 22 closest to the main structure 21 corresponds one-to-one with the long side of the main structure 21 on the right and has the same length. The long side of the third connecting plate 22 coincides with the long side of the main structure 21 on the right, so that the fourth arc-shaped surface 222 of the third connecting plate 22 connects with the outer side of the main structure 21 to form a smooth surface. The main structure 21 and the third connecting plate 22 are connected by a fifth fixing component, which can be a bolt and nut, or a buckle or other structure.

[0069] The third auxiliary plate 23 is also a rectangular plate. The third auxiliary plate 23 and the main structure 21 are located on opposite sides of the third connecting plate 22. The long side of the third auxiliary plate 23 near the third connecting plate 22 corresponds one-to-one with the long side of the third connecting plate 22 near the third auxiliary plate 23 and has the same length. The long side of the third connecting plate 22 near the third auxiliary plate 23 is connected to the long side of the third connecting plate 22 near the third auxiliary plate 23, so that the outer side of the third auxiliary plate 23 is connected to the fourth arc-shaped curved surface 222 of the third connecting plate 22 to form a smooth curved surface. The third connecting plate 22 and the third auxiliary plate 23 are connected by a sixth fixing component. The sixth fixing component can be a bolt and nut, or a buckle or other structure.

[0070] Figure 8 This is a schematic diagram of the prepreg laminate of the present invention being bent toward the third auxiliary plate.

[0071] Reference Figure 2 , Figure 3 , Figure 8 and Figure 9 As shown, the molding method for the Z-shaped preform 6 includes the following steps:

[0072] S0: Provide the C-shaped mold;

[0073] S1: A prepreg laminate 3 is provided, the prepreg laminate including a first side 31 and a second side 32 opposite to each other. The prepreg laminate 3 also includes a prepreg laminate outer side 33 and a prepreg laminate inner side 34. The first side 31 is attached to the long side of the outer side of the first auxiliary plate 12 of the mold away from the first connecting plate 111. Then, the prepreg laminate inner side 34 is brought closer to the first auxiliary plate 12 until the prepreg laminate inner side 34 is attached to the first auxiliary plate 12. During the attachment process, the fibers of the prepreg laminate outer side 33 are stretched. The length of the prepreg laminate 3 attached to the first auxiliary plate is pre-designed to form the fourth flange 62. The second side 32 is bent along direction A toward the web 112 until the prepreg laminate inner side 34 is attached to the web 112. The fibers of the prepreg laminate outer side 33 are stretched so that the prepreg laminate 3 is attached to the first connecting plate 111. The first arc-shaped surface 1141 of the prepreg laminate is attached. During the bending process of the first arc-shaped surface 1141 of the prepreg laminate 3 attached to the first connecting plate 111, the radius of the prepreg laminate 3 decreases. The fiber layup of the prepreg laminate 3 is always pulling the fibers towards the side where the radius of the prepreg laminate 3 decreases. The prepreg laminate 3 as a whole is not compressed. The non-arc fibers of the prepreg laminate 33 are stretched. The arc fibers of the prepreg laminate 33 do not need to produce a certain buckling to release the compressive stress. The prepreg laminate 33 will not accumulate material, so no wrinkle defects will be generated. Then, the C-shaped mold supporting the prepreg laminate 3 is placed in the preforming equipment for heat insulation or hot molding to obtain the second intermediate. In this process, the C-shaped mold is used to form the inner diameter R7 on the left side of the second intermediate. R7 is consistent with the radius of the first arc-shaped surface 1141 of the first connecting plate 111.

[0074] S2: Provides Z-shaped molds;

[0075] S3: Bend the second side 32 along direction C toward the third auxiliary plate 23 until the inner side 34 of the prepreg laminate is attached to the third auxiliary plate 23. During the attachment process, the fibers of the outer side 33 of the prepreg laminate are stretched so that the prepreg laminate 3 is attached to the fourth arc-shaped surface 222 of the third connecting plate 22. The length of the prepreg laminate 3 attached to the third auxiliary plate 23 is pre-designed to form the fifth edge strip 63. The radius of the outer side 33 of the prepreg laminate decreases during the bending process of attaching to the fourth arc-shaped surface 222 of the third connecting plate 22. The fiber layup of the prepreg laminate 3 always decreases in radius toward the prepreg laminate 3. One side is being stretched by the fibers, the prepreg stack 3 as a whole is not being compressed, the non-arc fibers of the outer side 33 of the prepreg stack are being stretched, the arc fibers of the outer side 33 of the prepreg stack do not need to produce a certain buckling to release the compressive stress, the outer side 33 of the prepreg stack will not produce material accumulation, thus no wrinkle defects will be produced; then the Z-shaped mold supporting the prepreg stack 3 is placed in the preforming equipment for heat insulation or heat molding to obtain the Z-shaped preform. In this process, the Z-shaped mold is used to form the outer diameter R10 on the right side of the Z-shaped preform 6, and R10 is consistent with the radius of the fourth arc surface 222 of the third connecting plate 22.

[0076] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A molding method for a curved structure, characterized in that, Includes the following steps: S0: A mold is provided, the mold including a main body, a first auxiliary plate and a second auxiliary plate, the first auxiliary plate and the second auxiliary plate are both rectangular plates, and the first auxiliary plate and the second auxiliary plate are respectively located on opposite sides of the main body; The main body includes a web, a first connecting plate, and a second connecting plate. The web is a rectangular plate, and the first and second connecting plates are both arc-shaped plates. The first and second connecting plates are located on opposite sides of the web. The long side of one side of the web is the same length as the long side of one side of the first connecting plate and they are connected, so that the outer side of the web is connected to the outer side of the first connecting plate. The long side of the other side of the web is the same length as the long side of one side of the second connecting plate and they are connected, so that the outer side of the web is connected to the outer side of the second connecting plate. The long side of the other side of the first connecting plate is the same length as the long side of one side of the first auxiliary plate and is connected to it, so that the outer side of the first connecting plate is connected to the outer side of the first auxiliary plate. The long side of the other side of the second connecting plate is connected to the long side of one side of the second auxiliary plate, so that the outer side of the second connecting plate is connected to the outer side of the second auxiliary plate. S1: Provide a prepreg stack, the prepreg stack including opposite sides, attach one side of the prepreg stack to the first auxiliary plate, and then bend the other side of the prepreg stack toward the web plate until the prepreg stack is attached to the web plate, so that the prepreg stack is attached to the first connecting plate. S2: Bend the other side of the prepreg stack toward the second auxiliary plate until the prepreg stack is in contact with the second auxiliary plate, so that the prepreg stack is in contact with the second connecting plate.

2. The molding method for a curved structure according to claim 1, characterized in that, In step S1, the step of attaching one side of the prepreg stack to the first auxiliary plate includes: attaching one side of the prepreg stack to the long side of the outer side of the first auxiliary plate away from the first connecting plate, so as to position the prepreg stack on the first auxiliary plate.

3. The molding method for a curved structure according to claim 2, characterized in that, During the bonding process between the prepreg laminate and the first auxiliary plate, the fiber 0° direction of the prepreg laminate must be parallel to the long side of the first auxiliary plate.

4. The molding method for a curved structure according to claim 1, characterized in that, Between steps S0 and S1, there is also step S01: forming the prepreg laminate by manual laying, automatic tape laying or automatic filament laying.

5. The molding method for a curved structure according to claim 4, characterized in that, The prepreg reinforcement includes carbon fiber, glass fiber or aramid fiber, and its matrix resin includes epoxy resin, polyimide resin or phenolic resin.

6. The molding method for a curved structure according to claim 1, characterized in that, In step S1, the web plate, the first auxiliary plate, the second auxiliary plate, the first connecting plate, and the second connecting plate are all made of any one of metal, wood, or resin polymer.

7. The molding method for a curved structure according to claim 1, characterized in that, Steps S1 to S2 are all performed in a preforming device, which includes either a thermal insulation film preforming device or a hot molding preforming device.

8. The molding method for a curved structure according to claim 1, characterized in that, In step S0, the web plate is connected to the first connecting plate, the web plate to the second connecting plate, the first connecting plate to the first auxiliary plate, and the second connecting plate to the second auxiliary plate through fixing parts.

9. The molding method for a curved structure according to claim 8, characterized in that, The fixing parts all include bolts and nuts.

10. The molding method for a curved structure according to claim 1, characterized in that, The thickness of the prepreg laminate ranges from 1 mm to 10 mm.

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