A frame-embedded preform integrated weaving method and preform

Abstract

The application provides a frame-embedded preform integrated weaving method and a preform. The weaving method comprises the following steps: providing a frame; connecting one end of N layers of warp yarns with a loom, winding the other end of the warp yarns around the front end of the frame, folding the other end of the warp yarns, connecting the other end of the warp yarns with the loom, and forming 2N layers of warp yarns on the frame; layering the warp yarns, wefting according to a selected fabric structure, and weaving to a selected preform structure size; separating the 2N layers of warp yarns into upper and lower parts, then making the rear end of the frame pass between the upper and lower parts of the warp yarns, and continuing to weave the end fabric; disconnecting the warp yarns, connecting a frame pressing plate with the frame, clamping the preform, and obtaining a frame-embedded preform. The method realizes the integration of the frame and the preform, reduces the deformation of the fabric caused by the inconsistent tension during assembly, effectively improves the strength of the preform, clamps the warp and weft yarns of the preform wound on the frame firmly by the frame pressing plate, and reduces the possibility that the preform is detached from the frame.

Description

Technical Field

[0001] This invention belongs to the technical field of fiber preform weaving methods, specifically relating to an integrated weaving method for frame-embedded preforms and the preform itself. Background Technology

[0002] Current trends in aircraft development emphasize lightweight design, long endurance, and extended range, requiring a high lift-to-drag ratio. Under current development conditions, relying on fixed-wing aircraft often sacrifices weight and space. Retractable and deployable flexible material wing structures offer an innovative design paradigm for future high-performance flexible aerospace vehicles. These flexible material wing structures allow for controlled wing retraction and deployment during flight, improving overall aircraft performance with minimal weight and space costs.

[0003] Flexible material wing structures consist of flexible materials and a frame. The flexible material typically employs a high-performance fiber three-dimensional woven preform. The common preparation method involves first weaving the fibers three-dimensionally to obtain the fiber three-dimensional woven preform, and then assembling the preform onto the frame and securing it with pressure plates. However, due to the tension between the warp and weft yarns during the weaving process, the preform fabric loosens after being removed from the loom due to the release of tension. Therefore, during preform assembly, tension must be applied to ensure the fabric is flat, wrinkle-free, and deformation-free, preventing failure due to loosening and deformation under harsh environmental conditions. However, during assembly, issues such as inconsistent preform tension leading to fabric deformation, insecure clamping causing the preform to detach from the frame during service, and cumbersome and inconsistent quality control processes for cutting, laying, and assembling the flexible preform fabric all contribute to problems. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a method for integrated weaving of a frame-embedded preform and the preform itself. This method achieves near-net-shape integration of the frame and preform, effectively reducing deformation of the flexible fabric caused by inconsistent tension of the preform during assembly, and effectively reducing the elongation of the flexible fabric in harsh environments. After the frame is embedded in the preform and woven, it is in a complete state, which can effectively improve the strength of the preform. The warp and weft yarns of the preform are wound around the front, rear, left, and right sides of the frame with tension, ensuring that the preform is flat within the frame. Under external force, the warp yarn elongation is low. The frame pressure plate firmly holds the warp and weft yarns of the preform wound on the frame, effectively reducing the risk of the preform coming out of the frame. This method eliminates the cutting, laying, and assembly processes required for separate weaving, effectively reducing manual labor, lowering production costs, improving production efficiency, and facilitating engineering applications.

[0005] To address the above problems, one aspect of the present invention provides a method for integrally weaving a frame-embedded preform, comprising the following steps:

[0006] S1. Provides a framework;

[0007] S2. Based on the selected number of warp layers 2N, connect one end of the N warp layers to the loom, and fold the other end around the front end of the frame and connect it to the loom, thus forming 2N warp layers on the frame;

[0008] S3. Layer the warp yarns, insert the weft yarns according to the selected preform fabric structure, and repeat the above steps until the selected preform structure size is woven.

[0009] S4. Separate the 2N layers of warp yarns into upper and lower parts, and then insert the rear end of the frame between the upper and lower parts of the warp yarns to continue weaving the finishing fabric.

[0010] S5. Disconnect the warp yarns and connect the frame pressure plate to the frame to clamp the preform, thus obtaining a frame-embedded preform.

[0011] Preferably, in step S3, when inserting the weft yarn, the weft yarn is introduced into a layer of warp yarn from one side of the frame, passes around the other side of the frame, and then is introduced into the next layer of warp yarn, passes around one side of the frame again, until the number of weft yarn layers is completed, and then the weft yarn passes around the side of the frame to insert the next weft.

[0012] Preferably, in step S3, when inserting the weft, the weft is inserted sequentially from the middle warp layer to the warp layers on both sides.

[0013] Preferably, the frame includes a front end, a rear end, a left side, and a right side; the two sides of the front end are respectively connected to one end of the left side and the right side, and the two sides of the rear end are respectively connected to the other end of the left side and the right side.

[0014] Preferably, the relative rotatable connection between the front end, rear end, left side, and right side of the frame allows the frame to be converted between unfolding and shrinking; when the frame is embedded in the preform, the frame is in an unfolded state.

[0015] Preferably, in step S1, a half-frame of the frame is provided, the half-frame including a front end of the frame, a left side of the frame, and a right side of the frame; the two sides of the front end of the frame are respectively connected to one end of the left side of the frame and one end of the right side of the frame.

[0016] In step S4, the 2N layers of warp yarns are separated into upper and lower parts. Then, the rear end of the frame is inserted between the upper and lower parts of the warp yarns. The two sides of the rear end of the frame are connected to the other end of the left side and the right side of the frame, respectively. Then, the finishing fabric is woven.

[0017] Preferably, the fabric structure of the preform is one or more of the following: a three-dimensional orthogonal structure or its derivative, a 2.5D structure or its derivative, a three-dimensional braided structure, and an in-plane multi-angle structure, and all of the fabric structures contain weft yarns.

[0018] Preferably, step S5 further includes bending the finishing fabric back to the rear end of the frame, connecting the frame pressure plate to the frame to clamp the preform, and then neatly cutting the finishing fabric along the rear end of the frame.

[0019] Preferably, the frame pressure plate includes an upper frame pressure plate and a lower frame pressure plate; in step S5, specifically, the upper frame pressure plate is connected to one side of the frame, and the lower frame pressure plate is connected to the other side of the frame, so that the preform is clamped.

[0020] Another aspect of the present invention provides a frame-embedded preform woven using the above-described frame-embedded preform integral weaving method.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The frame-embedded preform integrated weaving method of the present invention directly integrates the preform and the frame during weaving, achieving near-net-shape forming of the frame and preform. This avoids assembling the preform with the frame after weaving, effectively reducing deformation of the flexible fabric caused by inconsistent tension of the preform during assembly, and effectively reducing the elongation of the flexible fabric in harsh environments. Furthermore, since the frame is embedded in the preform and is in a complete state after weaving, the strength of the preform is effectively improved. The warp yarns of the preform are wound around the front and rear ends of the frame with tension, ensuring that the preform is flat within the frame and has a low warp elongation under external force. The frame pressure plate firmly holds the warp and weft yarns of the preform wound on the frame, effectively reducing the risk of the preform coming out of the frame. In addition, it eliminates the cutting, laying, and assembly processes that are required during separate weaving, effectively reducing manual labor, lowering production costs, improving production efficiency, and facilitating engineering applications. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the weaving process of the frame-embedded preform integrated weaving method described in the embodiment of the present invention;

[0024] Figure 2This is a schematic diagram showing the completed weaving process of the frame-embedded preform integrated weaving method described in this embodiment of the invention;

[0025] Figure 3 This is a schematic diagram of the frame structure in the integrated weaving method for frame-embedded preforms described in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the frame pressure plate in the frame-embedded preform integrated weaving method described in the embodiment of the present invention.

[0027] Wherein: 1-Front end of frame; 2-Left side of frame; 3-Right side of frame; 4-Rear end of frame; 5-Warp yarn; 6-Weft yarn; 7-Finishing fabric; 8-Preform; 9-Front end pressure plate of frame; 10-Left end pressure plate of frame; 11-Right end pressure plate of frame; 12-Rear end pressure plate of frame. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] One aspect of this invention provides a method for integrally weaving a frame-embedded preform, comprising the following steps:

[0030] S1. Provides a framework;

[0031] S2. Based on the selected number of warp layers 2N, connect one end of the N warp layers to the loom, and fold the other end around the front end of the frame and connect it to the loom, thus forming 2N warp layers on the frame;

[0032] S3. Layer the warp yarns, insert the weft yarns according to the selected preform fabric structure, and repeat the above steps until the selected preform structure size is woven.

[0033] S4. Separate the 2N layers of warp yarns into upper and lower parts, and then insert the rear end of the frame between the upper and lower parts of the warp yarns to continue weaving the finishing fabric.

[0034] S5. Disconnect the warp yarns and connect the frame pressure plate to the frame to clamp the preform, thus obtaining a frame-embedded preform.

[0035] The frame-embedded preform integrated weaving method of this invention integrates the preform and frame directly during weaving, achieving near-net-shape forming of the frame and preform. This avoids assembling the preform with the frame after weaving, effectively reducing deformation of the flexible fabric caused by inconsistent tension of the preform during assembly, and effectively reducing the elongation of the flexible fabric in harsh environments. Furthermore, because the frame is embedded in the preform and is in a complete state after weaving, the strength of the preform is effectively improved. The warp yarns of the preform are wound around the front and rear ends of the frame with tension, ensuring that the preform is flat within the frame and has low warp elongation under external force. The frame pressure plate firmly holds the warp and weft yarns of the preform wound on the frame, effectively reducing the risk of the preform coming out of the frame. In addition, it eliminates the cutting, laying, and assembly processes that are required during separate weaving, effectively reducing manual labor, lowering production costs, improving production efficiency, and facilitating engineering applications.

[0036] In some embodiments, the frame includes a front end, a rear end, a left side, and a right side; the two sides of the front end are respectively connected to one end of the left side and the right side, and the two sides of the rear end are respectively connected to the other end of the left side and the right side.

[0037] In some implementations, the material of the frame can be selected based on the actual usage conditions.

[0038] In some implementations, a first through hole is provided on the front end, left side, right side, and rear end of the frame, through which the four parts of the frame can be assembled and connected. The assembly and connection method of the frame can be adjusted according to the actual application, as long as the frame connection can be achieved.

[0039] In some embodiments, the relative rotatable connections between the front end, rear end, left side, and right side of the frame allow the frame to be extended or retracted; when the frame is woven into the embedded preform, the frame is in an extended state. Specifically, the four parts of the frame can be connected by hinges or other rotatable connections, allowing the frame to be extended or retracted, but the frame must remain in an extended state during integral weaving.

[0040] In some implementations, the frame and equipment bracket are equipped with a second through hole to facilitate connection between them. The connection method between the frame and the equipment can be adjusted according to the actual application, as long as the frame is fixed in place.

[0041] In some implementations, the frame may be a border frame or a reinforcing frame attached in the middle.

[0042] In some embodiments, in step S1, a half-frame of the frame is provided, the half-frame including a front end of the frame, a left side of the frame, and a right side of the frame; the two sides of the front end of the frame are respectively connected to one end of the left side of the frame and one end of the right side of the frame; in step S4, the 2N layers of warp yarns are separated into upper and lower parts, and then the rear end of the frame is inserted between the upper and lower parts of the warp yarns, and the two sides of the rear end of the frame are respectively connected to the other end of the left side of the frame and one end of the right side of the frame, and then the finishing fabric is woven.

[0043] In some embodiments, step S1 further includes installing and fixing the front end, left side and right side of the frame, and then placing it on the equipment bracket, with the front end, left side and right side of the frame corresponding to the front end, left end and right end of the equipment bracket respectively, and fixing the frame to the equipment bracket with bolts.

[0044] In some implementations, step S2 specifically includes: according to the selected number of warp layers 2N, connecting one end of the N warp layers to the loom, and folding the other end around the front end of the frame, passing it through the gap between the reed teeth, and connecting it to the corresponding position on the loom, thereby forming 2N warp layers on the frame.

[0045] In some embodiments, the fabric structure of the preform is one or more of the following: a three-dimensional orthogonal structure or a derivative thereof, a 2.5D structure or a derivative thereof, a three-dimensional braided structure, and an in-plane multi-angle structure, and all of the fabric structures contain weft yarns.

[0046] In some embodiments, during step S3, when inserting the weft yarn, the weft yarn is introduced into a layer of warp yarn from one side of the frame, passes around the other side of the frame, and then introduced into the next layer of warp yarn, passing around one side of the frame again, until the number of weft yarn layers is completed. Then, the weft yarn passes around the side of the frame and the next weft is inserted. In this way, the weft yarn of the preform is wound around the left and right ends of the frame with tension, ensuring that the preform is flat within the frame and that the weft yarn elongation is low under external force.

[0047] In some implementations, during step S3, when inserting the weft, the weft is inserted sequentially from the middle warp layer to the warp layers on both sides.

[0048] In some implementations, step S3 further includes: during the weft insertion process, the weft yarn is under tension, and the weft is beaten with a reed until the weft density is appropriate.

[0049] In some embodiments, step S5 further includes bending the finishing fabric back to the rear end of the frame, connecting the frame pressure plate to the frame to clamp the preform, and then neatly cutting the finishing fabric along the rear end of the frame.

[0050] Specifically, step S5 includes cutting the warp yarns at the end of the finishing fabric, bending the finishing fabric 180° back to the rear end of the frame, connecting and clamping the pressure plate at the rear end of the frame to the rear end of the frame, cutting the finishing fabric neatly along the rear end of the frame, and removing the frame and preform from the equipment support to obtain the frame-embedded preform.

[0051] In some embodiments, the frame pressure plate includes an upper frame pressure plate and a lower frame pressure plate; in step S5, specifically, the upper frame pressure plate is connected to one side of the frame, and the lower frame pressure plate is connected to the other side of the frame, so that the preform is clamped.

[0052] In some embodiments, the upper and lower pressure plates of the frame are provided with through holes to connect the upper and lower pressure plates to the frame, thereby ensuring that the warp and weft yarns of the preform wound on the frame are firmly clamped.

[0053] Another aspect of the present invention provides a frame-embedded preform woven using the above-described frame-embedded preform integrated weaving method.

[0054] In some embodiments, the preform can be a rectangle, trapezoid, triangular or other shape. Different shaped frames involve adding or subtracting warp yarns during the weaving process, which is a relevant technology in this industry.

[0055] In some embodiments, the fibers used in the preform can be one or more combinations of high-performance fibers such as carbon fiber, glass fiber, quartz fiber, silicon carbide fiber, aramid fiber, alumina fiber, and ultra-high molecular weight polyethylene fiber. Example 1

[0056] The frame-embedded preform integral weaving method described in this embodiment prepares a rectangular preform, including the following steps:

[0057] Step 1: Install and fix the front end 1, left side 2, and right side 3 of the frame. Connect the two sides of the front end of the frame to one end of the left side and one end of the right side of the frame, respectively. Then place it on the equipment bracket, aligning the front end 1, left side 2, and right side 3 with the front, left, and right ends of the equipment bracket, respectively. Secure the frame to the equipment bracket with bolts. The effective width of the front end 1 and rear end 4 of the frame is 1000mm, and the effective length of the left side 2 and right side 3 of the frame is 2000mm. (See the overall structural diagram of the frame as shown below.) Figure 3 (as shown)

[0058] Step 2: The preform parameters are designed as follows: fabric thickness 2mm, 2.5D fabric structure, 3k carbon fiber for warp and weft yarns, warp density 8 threads / cm, weft density 8 threads / cm, 800 warp rows, and 6 warp layers. Connect one end of the 3 warp yarns (5) to the loom, and fold the other end around the front of the frame to form 6 warp layers. Select an 80# reed. Pass each row of 6 warp yarns through the gaps between the reed teeth and connect them to the corresponding positions on the loom. Repeat this process until all 800 warp yarns (5) are yarned.

[0059] Step 3: After operating the equipment according to the 2.5D structural pattern, the warp yarns 5 are layered sequentially from the middle warp layer to the warp layers on both sides. For the first layer of warp yarns 5, the weft yarns 6 of the first layer are introduced from the left side 2 of the frame into the opening of the first layer of warp yarns 5 to the right side 3 of the frame. Then, the warp yarns 5 are layered into the second layer. The weft yarns 6 of the second layer are wrapped around the right side 3 of the frame and then introduced into the second layer of warp yarns 5 to the left side 2 of the frame. This process is repeated until the weft yarns 6 are introduced into all 6 layers of warp yarns 5. During the weft introduction process, the weft yarns 6 are under tension to ensure that the warp and weft yarns of the preform 8 are straight and the preform 8 is flat within the frame. Then, the weft is beaten with a reed until the weft density meets 8 yarns / cm.

[0060] Step 4, as follows Figure 1 As shown, when the required effective length of 2000mm is woven, the warp yarn 5 is separated from the middle layer into two parts: an upper layer of 3 warp yarns and a lower layer of 3 warp yarns. The rear end of the frame 4 is placed between the upper and lower warp yarn layers of the warp yarn 5. Then, the rear end of the frame 4 is connected to the left side 2 and the right side 3 of the frame. Then, the equipment is run to weave a section of finishing fabric 7 of about 100mm.

[0061] Step 5: Securely connect and clamp the front end pressure plate 9 of the frame to the front end 1 of the frame; securely connect and clamp the left end pressure plate 10 of the frame to the left side 2 of the frame; and securely connect and clamp the right end pressure plate 11 of the frame to the right side 3 of the frame. (The structure of the frame pressure plates is as follows...) Figure 4 (as shown)

[0062] Step 6: Cut the warp yarn 5 at the end of the fabric, bend the finishing fabric 7 180° back to the rear end 4 of the frame, and then firmly connect and clamp the rear end pressure plate 12 of the frame to the rear end 4 of the frame; then trim the finishing fabric 7 neatly along the rear end 4 of the frame; remove the frame and preform 8 from the equipment support to complete the integrated weaving of the frame-embedded preform. Figure 2 As shown.

[0063] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for integrally weaving a frame-embedded preform, characterized in that, Includes the following steps: S1. Provides a framework; S2. Based on the selected number of warp layers 2N, connect one end of the N warp layers to the loom, and fold the other end around the front end of the frame and connect it to the loom, thus forming 2N warp layers on the frame; S3. Layer the warp yarns, insert the weft yarns according to the selected preform fabric structure, and repeat the above steps until the selected preform structure size is woven. S4. Separate the 2N layers of warp yarns into upper and lower parts, and then insert the rear end of the frame between the upper and lower parts of the warp yarns to continue weaving the finishing fabric. S5. Disconnect the warp yarns and connect the frame pressure plate to the frame to clamp the preform, thus obtaining a frame-embedded preform. In step S3, when introducing the weft yarn, the weft yarn is introduced into a layer of warp yarn from one side of the frame, passes around the other side of the frame, and then introduced into the next layer of warp yarn, passes around one side of the frame again, until the number of weft yarn layers is completed. Then the weft yarn passes around the side of the frame and the next weft yarn is introduced.

2. The method for integrally weaving a frame-embedded preform according to claim 1, characterized in that: In step S3, when inserting the weft, the weft is inserted sequentially from the middle warp layer to the warp layers on both sides.

3. The method for integrally weaving a frame-embedded preform according to claim 1, characterized in that: The frame includes a front end, a rear end, a left side, and a right side; the two sides of the front end are respectively connected to one end of the left side and one end of the right side, and the two sides of the rear end are respectively connected to the other end of the left side and one end of the right side.

4. The method for integrally weaving a frame-embedded preform according to claim 3, characterized in that: The relative rotational connection between the front end, rear end, left side, and right side of the frame enables the frame to be expanded and contracted; when the frame is embedded in the preform, the frame is in an expanded state.

5. The method for integrally weaving a frame-embedded preform according to claim 3, characterized in that: In step S1, a half-frame of the frame is provided, the half-frame including a front end of the frame, a left side of the frame, and a right side of the frame; the two sides of the front end of the frame are respectively connected to one end of the left side of the frame and one end of the right side of the frame. In step S4, the 2N layers of warp yarns are separated into upper and lower parts. Then, the rear end of the frame is inserted between the upper and lower parts of the warp yarns. The two sides of the rear end of the frame are connected to the other end of the left side and the right side of the frame, respectively. Then, the finishing fabric is woven.

6. The method for integrally weaving a frame-embedded preform according to claim 3, characterized in that: The fabric structure of the preform is one or more of the following: a three-dimensional orthogonal structure or its derivative, a 2.5D structure or its derivative, or a three-dimensional braided structure, and all of the fabric structures contain weft yarns.

7. The method for integrally weaving a frame-embedded preform according to claim 1, characterized in that: Step S5 further includes bending the finishing fabric back to the rear end of the frame, connecting the frame pressure plate to the frame to clamp the preform, and then neatly cutting the finishing fabric along the rear end of the frame.

8. The method for integrally weaving a frame-embedded preform according to claim 1, characterized in that: The frame pressure plate includes an upper frame pressure plate and a lower frame pressure plate; in step S5, specifically, the upper frame pressure plate is connected to one side of the frame, and the lower frame pressure plate is connected to the other side of the frame, so that the preform is clamped.

9. A frame-embedded preform obtained by the integrated weaving method of frame-embedded preform as described in any one of claims 1-8.

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