A method for rapid laying of composite material layers with curvature

Abstract

The application discloses a kind of with curvature composite material layer fast laying method, belong to composite material forming technical field.It includes: the prepreg sheet is placed on the surface of curved mould, along the direction of the inner side edge close to curved mould to outer side edge preset sequentially connected N operation area;The fitting process is sequentially carried out from the first operation area to the Nth operation area;The fitting of each operation area includes: with compaction tool press the middle position of operation area, then under the condition of pressurization, from middle position to the length direction of prepreg sheet respectively compaction fitting is carried out, and the curvature of operation area is consistent with the curvature of the corresponding part of curved mould, and the layer of material sheet with curvature is formed;Unfold layer of material sheet, the obtained plane sector material sheet is placed on the arc beam mould to be laid, and hot diaphragm forming is carried out.This method can avoid the generation of wrinkle in the inner side and outer side edge of prepreg during laying process, so as to avoid the formation of defect in composite material structure.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, and more specifically, to a method for rapid layup of composite material layers with curvature. Background Technology

[0002] In the manufacturing process of composite material structures with curvature, the fiber direction of the prepreg needs to be in the direction of the curve. It can be directly manufactured by complex and sophisticated equipment such as automatic fiber placement machine or tape laying machine, or the intermediate curved or flat sheet can be manufactured first by automatic fiber placement machine or tape laying machine, and then the parts can be laid up by thermal insulation film.

[0003] However, currently, automatic fiber placement machines or tape laying machines are high-end equipment in the composite materials industry, with high costs and low adoption rates. Therefore, composite materials are still mainly laid manually. Typically, when manually laying curved parts, it is necessary to manually lay the slits into narrow sheets. The narrower the sheet, the easier it is to lay, but the lower the efficiency. The wider the sheet, the higher the efficiency, but if the width of the slit exceeds the deformation limit, wrinkles will form during the laying process, resulting in defects in the structure.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a rapid layup method for composite materials with curvature, which can avoid wrinkles on the inner and outer edges of the prepreg during the layup process, thereby avoiding defects in the composite material structure.

[0006] This application can be implemented as follows:

[0007] This application provides a method for rapid application of composite material layup with curvature, which includes the following steps:

[0008] S1: The prepreg sheet without curvature is bonded to the curved mold to form a layup sheet with curvature;

[0009] The curved mold includes an inner side corresponding to the first radius and an outer side corresponding to the second radius;

[0010] The bonding process includes: placing the prepreg sheet on the surface of the curved mold, and pre-setting N operating areas connected sequentially along the direction from the inner side of the curved mold to the outer side of the curved mold; the bonding process is carried out sequentially from the first operating area to the Nth operating area; the bonding of each operating area includes: pressing the middle position of the operating area with a compaction tool, and then, under pressure, compacting and bonding from the middle position towards the length direction of the prepreg sheet, and ensuring that the curvature of the operating area is consistent with the curvature of the corresponding part of the curved mold;

[0011] S2: Unfold the ply sheet to obtain a planar fan-shaped sheet with curvature;

[0012] S3: Place the flat fan-shaped sheet onto the arc-shaped beam mold to be laid, and then perform heat insulation film forming.

[0013] In an optional embodiment, the 0° direction of the fibers in the layup sheet is along the ridge of the curved die, and the 0° direction of the fibers in the layup sheet gradually changes along the length direction of the inner or outer side of the curved die.

[0014] In an optional implementation, the pressure applied is 45-55 N.

[0015] In an optional implementation, the compaction tool includes a pressure roller.

[0016] In an optional implementation, the pressure roller has a rolling speed of 4-6 mm / s.

[0017] In an optional implementation, when the layup sheet is multi-layered, the multi-layered sheet is laid sequentially from bottom to top on the surface of the curved mold, and the method and conditions for laying each layer are the same.

[0018] In an optional implementation, the curved beam mold includes a C-shaped beam mold.

[0019] In an optional embodiment, during the thermal diaphragm forming process, the heating temperature is 65-85°C and the heating time is 15-35 minutes.

[0020] In an optional embodiment, the vacuuming process during the thermal insulation film forming process includes a first stage and a second stage performed sequentially.

[0021] The vacuum pumping rate for the first stage does not exceed 2 kPa / min, and the vacuum pumping rate for the second stage is 2-10 kPa / min.

[0022] In an optional implementation, the vacuuming process also includes shaping, cooling, and depressurization steps.

[0023] The beneficial effects of this application include:

[0024] This application involves first placing (laying) prepreg sheets on the surface of a curved mold, and then sequentially bonding them from the first to the Nth operating areas. The bonding of each operating area includes: pressing the center of the operating area with a compaction tool, and then, under pressure, compacting and bonding the prepreg sheet from the center outwards along its length, ensuring that the curvature of the operating area matches the curvature of the corresponding part of the curved mold. Furthermore, unfolding the layup sheet yields a planar fan-shaped sheet with curvature. Placing this planar fan-shaped sheet with curvature in an arc-beam mold and performing heat-insulating film forming enables rapid and high-quality material laying, preventing wrinkles on the inner and outer edges of the prepreg during the laying process, thereby avoiding defects in the composite material structure. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the fiber orientation of the layup sheet in S1 of Example 1;

[0027] Figure 2 This is a schematic diagram showing the location of the first operating area in S1 of Example 1;

[0028] Figure 3 This is a schematic diagram showing the location of the fourth operation area in S1 of Example 1;

[0029] Figure 4 This is a schematic diagram of the planar sector-shaped sheet with curvature in S2 of Example 1;

[0030] Figure 5 This is a schematic diagram of the planar fan-shaped curved sheet placed in the C-beam mold in S3 of Example 1.

[0031] Icons: 10-Pressure roller; 20-Curved mold; 30-Prepreg sheet; 40-Flat mold; 50-Flat fan-shaped sheet with curvature; 60-C-beam mold. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0033] The following is a detailed description of the rapid layup method for curved composite materials provided in this application.

[0034] This application proposes a method for rapid application of composite material layups with curvature, which includes the following steps:

[0035] S1: The prepreg sheet without curvature is bonded to the curved mold to form a layup sheet with curvature.

[0036] The curved mold includes an inner side corresponding to a first radius and an outer side corresponding to a second radius. The first radius is smaller than the second radius.

[0037] For example, prepregs without curvature can be rectangular, or any other feasible shape.

[0038] The above bonding process includes: placing (laying) the prepreg sheet on the surface of the curved mold, and pre-setting N operating areas connected sequentially along the direction from the inner side of the curved mold to the outer side of the curved mold; the bonding process is carried out sequentially from the first operating area to the Nth operating area; the bonding of each operating area includes: pressing the middle position of the operating area with a compaction tool, and then compacting and bonding from the middle position towards the length direction of the prepreg sheet under pressure, and making the curvature of the operating area consistent with the curvature of the corresponding part of the curved mold.

[0039] Taking a rectangular prepreg without curvature as an example, the two parallel long sides of the prepreg are defined as the first long side and the second long side, and the two parallel short sides are defined as the first short side and the second short side. During installation, the first long side faces the inner edge of the curved mold, and the second long side faces the outer edge of the curved mold. During operation, the prepreg is applied from the first long side (corresponding to the inner edge) to the second long side (corresponding to the outer edge).

[0040] Following the specific bonding sequence described above helps to ensure that the sheet material adheres tightly to the mold surface, preventing wrinkles from forming in the edge areas of the prepreg material near the first long side and the second long side.

[0041] It should be noted that in the above N operating areas, the distance from the inner side to the outer side of each operating area along the curved mold can be equal or unequal.

[0042] In this application, the distance from the "middle position of the operating area" to the first short side and the distance to the second short side may be unequal. In some typical embodiments, the middle position refers to the center position of the prepreg, and its distance to the first short side and the distance to the second short side are equal, so as to obtain a more consistent bonding effect on both sides of the middle area.

[0043] For reference, in the layup sheet provided in this application, the 0° direction of the fibers is along the ridge line of the curved mold, and the 0° direction of the fibers in the layup sheet gradually changes along the length direction of the inner or outer side of the curved mold.

[0044] It should be emphasized that the number of layers of the layup sheet in this application can be only 1 layer, or it can be 2, 3, 4 or more layers.

[0045] When a ply sheet is formed from multiple layers, the layers are laid sequentially from bottom to top on the surface of a curved mold, with each layer laid using the same method and conditions. That is, the laying process for the second layer and each subsequent layer is the same as that for the first layer.

[0046] In some embodiments, the pressure applied to the prepreg during the bonding process can be 45-55N, such as 45N, 46N, 47N, 48N, 49N, 50N, 51N, 52N, 53N, 54N or 55N, or any other value within the range of 45-55N.

[0047] If the pressure is less than 45N, it will not be conducive to the material sheet sticking tightly to the mold, causing the material sheet to slip as a whole; if the pressure is greater than 55N, an additional device is required to apply the load, and if the pressure is too high, the material sheets will be too close together, which will not be conducive to the slippage process between the material sheet layers during the subsequent heat insulation film forming process.

[0048] In some embodiments, the compaction tool may include, for example, a pressure roller. In addition, any other tool capable of compacting the prepreg may be used. In some embodiments, direct hand compaction is also possible.

[0049] For example, when the compaction tool is a pressure roller, the roller pressing speed can be 4-6 mm / s, such as 4 mm / s, 4.5 mm / s, 5 mm / s, 5.5 mm / s or 6 mm / s, or any other value in the range of 4-6 mm / s.

[0050] If the roller speed is less than 4 mm / s, the laying efficiency is too low; if the roller speed is greater than 6 mm / s, the material sheet may not be reliably compacted.

[0051] Continuing from the above, the bonding sequence can be referenced as follows: Press and bond from the center of the first operating area towards the edges of the first and second short sides (you can press towards one side first and then towards the other, or press towards both sides simultaneously); then press and bond from the center of the first operating area towards the second operating area, then press and bond from the center of the second operating area towards the edges of the second and second short sides; then press and bond from the center of the second operating area towards the third operating area, and so on.

[0052] By using the specific bonding method described above, the problem of wrinkles on the inner and outer edges of the prepreg during conventional laying can be avoided, thereby preventing defects from forming in the composite material structure.

[0053] S2: Unfold the ply sheet to obtain a flat fan-shaped sheet with curvature.

[0054] S3: Place the flat fan-shaped sheet onto the arc-shaped beam mold to be laid, and then perform heat insulation film forming.

[0055] The curved beam mold may, by way of example but not by way of limitation, include a C-shaped beam mold.

[0056] For reference, the heating temperature during the thermal insulation film forming process can be 65-85℃, such as 65℃, 70℃, 75℃, 80℃ or 85℃, or any other value within the range of 65-85℃.

[0057] The heating time can be 15-35 minutes, such as 15 minutes, 20 minutes, 25 minutes, 30 minutes or 35 minutes, or any other value within the range of 15-35 minutes.

[0058] The vacuuming process in the thermal insulation film forming process includes a first stage and a second stage performed sequentially.

[0059] The vacuuming rate for the first stage shall not exceed 2 kPa / min, such as 2 kPa / min, 1.5 kPa / min, 1 kPa / min, or 0.5 kPa / min. The vacuuming rate for the second stage may be 2-10 kPa / min, such as 2 kPa / min, 3 kPa / min, 4 kPa / min, 5 kPa / min, 6 kPa / min, 7 kPa / min, 8 kPa / min, 9 kPa / min, or 10 kPa / min.

[0060] Performing the first stage of vacuuming under the above conditions allows the flat fan-shaped material to gradually and completely adhere to the curved beam mold, preventing wrinkles from appearing at the bend; performing the second stage of vacuuming under the above conditions can effectively shape the adhered material.

[0061] It should be noted that other details regarding the forming of thermal diaphragms that are not further described in detail can be found in the relevant existing technologies, and will not be elaborated upon here.

[0062] Furthermore, after vacuuming, steps such as shape preservation, cooling, and pressure relief may also be included.

[0063] For reference, after shaping, allow the molded part to cool naturally until it reaches the demolding temperature (e.g., ≤40℃). Then, depressurize to normal pressure and remove the molded part from the curved mold beam.

[0064] It should be noted that for other aspects such as shape retention, cooling, and pressure relief that are not further detailed, please refer to relevant existing technologies, which will not be elaborated upon here.

[0065] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0066] Example 1

[0067] This embodiment provides a method for rapid application of composite material layups with curvature, which includes the following steps:

[0068] S1: The prepreg sheet 30 without curvature is bonded to the curved mold 20 to form a layup sheet with curvature (only 1 layer).

[0069] The curved mold 20 includes an inner side corresponding to the first radius and an outer side corresponding to the second radius, with curvatures of 0.5m and 0.5m respectively. -1 and 0.25m -1 The prepreg without curvature is rectangular (1m × 2m). Its two parallel long sides are defined as the first long side and the second long side, and its two parallel short sides are defined as the first short side and the second short side. During installation, the first long side faces the inner edge of the curved mold 20, and the second long side faces the outer edge of the curved mold 20. For example... Figure 1 As shown, the 0° direction of the fibers in the above-mentioned ply sheet is along the ridge line of the curved mold 20, and the 0° direction of the fibers in the ply sheet gradually changes along the length direction of the inner or outer side of the curved mold 20.

[0070] Specifically, the first layer of prepreg sheet 30 is placed (laid) on the surface of the curved mold 20, and four operating areas are pre-connected sequentially along the direction from the inner side of the curved mold 20 to the outer side of the curved mold 20; the bonding process is carried out sequentially from the first operating area to the fourth operating area (refer to...). Figure 2 and Figure 3 (Proceeding in top-to-bottom order); Each operating area includes: pressing the center of the operating area with pressure roller 10, and then, under a condition of 50N, rolling from the center at a speed of 5mm / s towards the length of the prepreg sheet 30 (i.e., referring to...). Figure 2 As shown, the material is pressed and bonded along the dotted lines to the left and right, and the curvature of the operating area is made consistent with the curvature of the corresponding part of the curved mold 20.

[0071] S2: Unfold the layup sheet to obtain a planar mold 40 and a planar fan-shaped sheet with curvature 50 adhered to the surface of the planar mold 40 (e.g., ...). Figure 4 (As shown).

[0072] S3: As Figure 5 As shown, a planar fan-shaped sheet of material 50 with curvature is placed on a C-beam mold 60, and then heat insulation film is formed.

[0073] The heating temperature during the thermal insulation membrane forming process is 75℃, and the heating time is 25 minutes. The vacuuming process during the thermal insulation membrane forming process includes a first stage and a second stage performed sequentially. The vacuuming rate for the first stage is 1 kPa / min, and the vacuuming rate for the second stage is 5 kPa / min.

[0074] S4: After vacuuming, maintain the shape, allow it to cool naturally to 30°C, release the pressure to normal pressure, and then remove the molded part from the arc-shaped mold beam.

[0075] Example 2

[0076] This embodiment provides a method for rapid application of composite material layups with curvature, which includes the following steps:

[0077] S1: The prepreg sheet without curvature is bonded to the curved mold to form a curved layup sheet (1 layer only).

[0078] The curved mold includes an inner side corresponding to the first radius and an outer side corresponding to the second radius, with curvatures of 1m and 1m respectively. -1 and 0.5m -1 The prepreg without curvature is rectangular (0.5m × 1m). Its two parallel long sides are defined as the first and second long sides, and its two parallel short sides are defined as the first and second short sides. During layup, the first long side faces the inner edge of the curved mold, and the second long side faces the outer edge of the curved mold. The 0° direction of the fibers in the layup sheet follows the ridge line of the curved mold, and the 0° direction of the fibers gradually changes along the length of the inner or outer edge of the curved mold.

[0079] Specifically, the first layer of prepreg sheet is placed (laid) on the surface of the curved mold, and three operating areas are pre-connected sequentially along the direction from the inner side of the curved mold to the outer side of the curved mold; the bonding process is carried out sequentially from the first to the third operating area; each operating area includes: pressing the center position of the operating area with a pressure roller, and then pressing and bonding the prepreg sheet from the center position at a roller pressing rate of 4 mm / s under the condition of 45 N, and making the curvature of the operating area consistent with the curvature of the corresponding part of the curved mold.

[0080] S2: Unfold the layup sheet to obtain a planar mold and a planar fan-shaped sheet with curvature attached to the surface of the planar mold.

[0081] S3: Place the flat fan-shaped curved sheet on the C-beam mold, and then perform heat insulation molding.

[0082] The heating temperature during the thermal separator molding process is 65℃, and the heating time is 35 minutes. The vacuuming process during the thermal separator molding process includes a first stage and a second stage performed sequentially. The vacuuming rate for the first stage is 2 kPa / min, and the vacuuming rate for the second stage is 10 kPa / min.

[0083] S4: After vacuuming, maintain the shape, allow it to cool naturally to 30°C, release the pressure to normal pressure, and then remove the molded part from the arc-shaped mold beam.

[0084] Example 3

[0085] This embodiment provides a method for rapid application of composite material layups with curvature, which includes the following steps:

[0086] S1: The prepreg sheet without curvature is bonded to the curved mold to form a curved layup sheet (1 layer only).

[0087] The curved mold includes an inner side corresponding to the first radius and an outer side corresponding to the second radius, with curvatures of 1m and 1m respectively. -1 and 0.25m -1 The prepreg without curvature is rectangular (1.5m × 3m). Its two parallel long sides are defined as the first and second long sides, and its two parallel short sides are defined as the first and second short sides. During layup, the first long side faces the inner edge of the curved mold, and the second long side faces the outer edge of the curved mold. The 0° direction of the fibers in the layup sheet follows the ridge line of the curved mold, and the 0° direction of the fibers gradually changes along the length of the inner or outer edge of the curved mold.

[0088] Specifically, the first layer of prepreg sheet is placed (laid) on the surface of the curved mold, and six operating areas are pre-connected sequentially along the direction from the inner side of the curved mold to the outer side of the curved mold; the bonding process is carried out sequentially from the first to the sixth operating area; each operating area includes: pressing the center position of the operating area with a pressure roller, and then pressing and bonding the prepreg sheet from the center position at a roller pressing rate of 6 mm / s under the condition of 55 N, and making the curvature of the operating area consistent with the curvature of the corresponding part of the curved mold.

[0089] S2: Unfold the layup sheet to obtain a planar mold and a planar fan-shaped sheet with curvature attached to the surface of the planar mold.

[0090] S3: Place the flat fan-shaped curved sheet on the C-beam mold, and then perform heat insulation molding.

[0091] The heating temperature during the thermal insulation membrane forming process is 85℃, and the heating time is 15 minutes. The vacuuming process during the thermal insulation membrane forming process includes a first stage and a second stage performed sequentially. The vacuuming rate for the first stage is 0.5 kPa / min, and the vacuuming rate for the second stage is 2 kPa / min.

[0092] S4: After vacuuming, maintain the shape, allow it to cool naturally to 30°C, release the pressure to normal pressure, and then remove the molded part from the arc-shaped mold beam.

[0093] Example 4

[0094] The difference between this embodiment and Embodiment 1 is that the curved ply sheet has 5 layers. The size and material of each layer of prepreg are the same. The laying process of the first layer is the same as S2 in Embodiment 1, and the laying process and conditions of the remaining layers are the same as the first layer.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 1 is that S1 and S2 were not performed; the prepreg was directly laid on the C-beam mold according to S3, and then S4 was performed.

[0097] The results showed that this method causes wrinkles on both the inner and outer edges of the prepreg, resulting in defects in the final composite material structure.

[0098] In summary, the rapid layup method for curved composite materials provided in this application can achieve rapid and high-quality material layup, and can avoid wrinkles on the inner and outer edges of the prepreg during the layup process, thereby avoiding defects in the composite material structure.

[0099] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for rapid application of composite material layups with curvature, characterized in that, Includes the following steps: S1: The prepreg sheet without curvature is bonded to the curved mold to form a layup sheet with curvature; The curved mold includes an inner side corresponding to the first radius and an outer side corresponding to the second radius; The bonding process includes: placing the prepreg sheet on the surface of the curved mold, and pre-setting N operation areas connected sequentially along the direction from the inner side of the curved mold to the outer side of the curved mold; the bonding process is performed sequentially from the first operation area to the Nth operation area; the bonding of each operation area includes: pressing the middle position of the operation area with a compaction tool, and then, under pressure, compacting and bonding from the middle position towards the length direction of the prepreg sheet, and making the curvature of the operation area consistent with the curvature of the corresponding part of the curved mold; S2: Unfold the ply sheet to obtain a planar fan-shaped sheet with curvature; S3: Place the flat fan-shaped sheet on the arc-shaped beam mold to be laid, and then perform heat insulation film forming; The 0° direction of the fibers in the ply sheet is along the ridge line of the curved mold, and the 0° direction of the fibers in the ply sheet gradually changes along the length direction of the inner or outer side of the curved mold. The pressure applied is 45-55N, and the compaction tool is a pressure roller with a roller speed of 4-6mm / s; During the thermal insulation membrane forming process, the heating temperature is 65-85℃ and the heating time is 15-35min. The vacuuming process during the thermal insulation membrane forming process includes a first stage and a second stage performed sequentially. The vacuuming rate corresponding to the first stage does not exceed 2KPa / min, and the vacuuming rate corresponding to the second stage is 2-10KPa / min.

2. The rapid layup method for composite materials with curvature according to claim 1, characterized in that, When the layup sheet is multi-layered, the multi-layered sheet is laid sequentially from bottom to top on the surface of the curved mold, and the method and conditions for laying each layer are the same.

3. The rapid layup method for composite materials with curvature according to claim 1, characterized in that, The arc-shaped beam mold includes a C-shaped beam mold.

4. The rapid layup method for composite materials with curvature according to claim 1, characterized in that, After vacuuming, the process also includes shape preservation, cooling, and pressure relief steps.

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