Preform of bulkhead in aircraft and manufacturing method therefor

Abstract

The present invention relates to a preform of a bulkhead in an aircraft and a manufacturing method therefor. The preform of the bulkhead is provided with edge strips located at two ends of the bulkhead and a web located in the middle of the preform and connecting the edge strips. The web has a curvature in the longitudinal direction of the web. The web is laid with 0-degree yarns extending without wrinkles at a 0-degree angle relative to the longitudinal direction of the web. By means of the present invention, the 0-degree yarns can be arranged on the web of the preform of the bulkhead in the longitudinal direction of the web without wrinkles, such that the 0-degree yarns have tension in the longitudinal direction of the web, thereby meeting stress requirements for the bulkhead in the longitudinal direction, ensuring smoothness and flatness of fibers of the preform, improving the adaptability of the preform of the bulkhead to curved surfaces, increasing the manufacturing efficiency of the preform of the bulkhead, and ensuring manufacturing quality and reliability.

Description

Preform of aircraft frame and its manufacturing method Technical Field

[0001] This invention relates to the field of aircraft bulkheads, and particularly to a preform of an aircraft bulkhead and a method for manufacturing the same. Background Technology

[0002] Bulkheads are widely used in various aircraft, such as aircraft fuselages, missile bodies, and airborne pods. Their primary function is to serve as a major load-bearing and load-bearing structure, supporting various forces and moments generated during flight, such as those experienced by aircraft and missiles. By supporting and securing various components of the aircraft, such as wings, tail, and fuselage, they provide support for the aircraft's skin, ensuring overall structural stability and maintaining the shape of the aircraft's main body, such as the fuselage, ensuring its streamlined design and aerodynamic performance, thereby guaranteeing safety and stability during flight. Secondly, bulkheads can improve the structural rigidity and fatigue resistance of aircraft, such as aircraft, by effectively distributing and transferring various loads during flight, preventing structural damage or fatigue cracks caused by localized stress concentration. Furthermore, bulkheads can improve cabin comfort. Due to proper placement and shape design within the aircraft structure, bulkheads can reduce vibration and noise during flight. Simultaneously, bulkheads provide necessary support and partitioning for the cabin, allowing seats, electronic equipment, overhead bins, etc., to be stably secured to the aircraft, providing a more comfortable passenger environment.

[0003] It is evident that bulkheads play a crucial role in the structures of aircraft such as aircraft fuselages, missile bodies, and airborne pods. However, existing bulkhead designs are not entirely satisfactory. A bulkhead typically consists of edge strips at both ends and a web in the middle. To withstand stresses in different directions, bulkheads extensively utilize textile fibers; specifically, yarns interwoven at different angles are used in various components of the bulkhead, such as the edge strips and the web. These yarns bear different stresses in different angular directions to meet the design requirements of the bulkhead, particularly in terms of stress. The web of the bulkhead usually has a certain curvature in its longitudinal direction to fit the roughly cylindrical shape of an aircraft, such as an aircraft fuselage. This curvature results in different inner and outer radii of the web, making the yarns laid along this curvature prone to wrinkling and loosening, thus losing tension and rendering the yarns in that direction ineffective, failing to meet design requirements and creating potential safety hazards. Therefore, currently, there are no 0-degree yarns laid at a 0-degree angle relative to the longitudinal direction in the web of bulkheads. Summary of the Invention

[0004] The purpose of this invention is to provide a preform for an aircraft bulkhead and its manufacturing method, which at least partially solves the problems in the prior art.

[0005] The objective is achieved by a method for manufacturing a preform for an aircraft bulkhead according to the present invention. Here, the preform has edge strips at both ends and a web connecting the edge strips in the middle of the preform, the web having an arc in its longitudinal direction. According to the present invention, the method includes the step of laying a 0-degree yarn, stretched without wrinkles at a 0-degree angle relative to its longitudinal direction, on the web.

[0006] This invention enables the seamless application of 0-degree yarns along the longitudinal direction of the web of a preformed partition frame, allowing the 0-degree yarns to have tension in the longitudinal direction of the web. This satisfies the stress requirements of the partition frame in that longitudinal direction, ensures the smoothness of the preformed fiber, improves the adaptability of the preformed partition frame to curved surfaces, increases the manufacturing efficiency of the preformed partition frame, and ensures manufacturing quality and reliability.

[0007] In one embodiment of the present invention, the method further includes laying 0-degree yarn on the edge strips of the preformed frame. Thus, 0-degree yarn is present on both the web and the edge strips of the frame. Therefore, the stress requirements of the preformed frame in the longitudinal direction of the web can be met, both on the web and the edge strips, further improving the adaptability of the preformed frame to various curved surfaces.

[0008] In one embodiment of the invention, the step of laying the 0-degree yarn includes: laying and weaving auxiliary yarns on both sides of the 0-degree yarn to fix it. Here, auxiliary yarns are used to fix the 0-degree yarn without the need for other weaving layers. The auxiliary yarns provide temporary fixation for the 0-degree yarn during the manufacturing process of the preform. After subsequent resin impregnation, the 0-degree yarn is fixed by the cured resin, at which point the previous auxiliary yarns can be melted away.

[0009] In one embodiment of the present invention, the step of laying 0-degree yarn further includes: drawing the 0-degree yarn from the yarn bobbin holder and passing it through the yarn bobbin tube mounted on the braiding machine, leading it to the braiding ring fitted on the mandrel; and then guiding the 0-degree yarn onto the mandrel via the braiding ring and having it pulled by the mandrel. An exemplary method of laying 0-degree yarn is given herein. This method allows multiple 0-degree yarns to be laid on the mandrel and then placed into the preform.

[0010] In one embodiment of the present invention, the step of laying the auxiliary yarn includes: drawing the auxiliary yarn from the yarn carrier mounted on the braiding machine and guiding it to the braiding loops on both sides of the 0-degree yarn; guiding the auxiliary yarn to the mandrel via the braiding loops, and clamping and fixing the 0-degree yarn to the mandrel using the auxiliary yarn. An exemplary braiding method for the auxiliary yarn is given here. This braiding method enables the auxiliary yarn to be guided to the mandrel via the braiding loops, thereby clamping and fixing the 0-degree yarn to the mandrel. Thus, the 0-degree yarn is fixed using the auxiliary yarn.

[0011] In one embodiment of the invention, the step of laying the 0-degree yarn includes: wrapping and winding the 0-degree yarn with a 90-degree yarn that extends at a 90-degree angle relative to the longitudinal direction of the web. Here, instead of the auxiliary yarn, the next weaving layer, i.e., the 90-degree yarn, is used to fix the 0-degree yarn. That is, the 90-degree yarn extends perpendicular to the 0-degree yarn, wrapping and winding the 0-degree yarn to form a mesh with numerous rectangular squares.

[0012] In one embodiment of the invention, the step of laying the 90-degree yarn further includes: guiding the 0-degree yarn from the yarn bobbin through the yarn spreader onto the mandrel; and guiding the 90-degree yarn from the winding machine through the yarn spreader onto the mandrel, wherein the 0-degree yarn is wrapped and fixed onto the mandrel with the 90-degree yarn. An exemplary specific implementation of using 90-degree yarn to fix the 0-degree yarn is given here. In this way, it is possible to simply wrap the 0-degree yarn with 90-degree yarn, thereby interweaving and fixing the 0-degree and 90-degree yarns together, satisfying the corresponding requirements for yarn stress in the directions forming 0-degree and 90-degree angles relative to the longitudinal direction of the web.

[0013] In one embodiment of the invention, the step of laying the 0-degree yarn further includes: weaving angle yarns on both sides of the 0-degree yarn, extending at an angle different from 0 degrees or 90 degrees relative to the longitudinal direction of the web. Here, the angle yarns form any angle relative to the longitudinal direction of the web, different from 0 degrees or 90 degrees. Instead of auxiliary yarns, the next weaving layer, i.e., the angle yarns, is used to fix the 0-degree yarns. That is, the angle yarns cover and fix the 0-degree yarns at any angle different from 0 degrees or 90 degrees, forming a mesh with numerous diamond or triangular grids.

[0014] In one embodiment of the invention, the step of laying the angle yarn further includes: drawing the 0-degree yarn from the yarn carrier through the braiding ring onto the mandrel; drawing the angle yarn from both sides of the 0-degree yarn from the braiding machine to the braiding ring, and then through the braiding ring onto the mandrel, wherein the 0-degree yarn is wrapped and fixed to the mandrel with the angle yarn. An exemplary specific implementation of using angle yarn to fix the 0-degree yarn is given here. In this way, the 0-degree yarn can be simply wrapped and fixed with angle yarn, so that the 0-degree yarn and the angle yarn are interwoven and fixed to each other, satisfying the corresponding requirements for yarn stress in directions forming angles different from 0 degrees and 90 degrees relative to the longitudinal direction of the web.

[0015] In one embodiment of the present invention, the step of laying the angle yarn further includes: guiding the 0-degree yarn from the yarn bobbin through the yarn spreader onto the mandrel; guiding the angle yarn on both sides of the 0-degree yarn through the yarn spreader onto the mandrel, wherein the 0-degree yarn is wrapped and fixed onto the mandrel with the angle yarn. Another exemplary implementation of using angle yarn to fix the 0-degree yarn is given here. In the absence of a braiding machine, the yarn spreader can be used instead of the braiding loops of the braiding machine to evenly spread the yarn, facilitating subsequent laying onto the mandrel, and ultimately achieving simple wrapping and fixing of the 0-degree yarn with angle yarn.

[0016] According to another aspect, the present invention also relates to a preform of an aircraft frame manufactured according to the aforementioned method, the preform having edge strips at both ends and a web located in the middle of the preform and connecting the edge strips, the web having an arc in its longitudinal direction. According to the invention, the web has 0-degree yarns that extend without wrinkles at a 0-degree angle relative to the longitudinal direction. In one embodiment of the invention, the edge strips are also covered with 0-degree yarns.

[0017] The various embodiments and advantages described above for the method of manufacturing the preform of the partition frame are also applicable to the preform of the partition frame of the present invention, and will not be repeated here. Attached Figure Description

[0018] To better understand the above and other objects, features, advantages, and functions of this application, reference can be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings denote the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate the preferred embodiments of this application and do not limit the scope of this application in any way; the parts in the drawings are not drawn to scale.

[0019] Figure 1 is a partial perspective view of the preform of the aircraft frame;

[0020] Figure 2 schematically shows the curved longitudinal orientation of the preform of the partition frame in Figure 1;

[0021] Figure 3 shows the case where 90-degree yarn and angle yarn are used to fix 0-degree yarn for the preform of the partition frame in Figure 1;

[0022] Figure 4 shows the case where auxiliary yarn is used to fix the 0-degree yarn for the preform of the partition frame in Figure 1. Detailed Implementation

[0023] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings. The embodiments described herein are merely preferred embodiments based on this application; those skilled in the art can conceive of other ways to implement this application based on the preferred embodiments, and such other ways also fall within the scope of this application.

[0024] The exemplary embodiments of the present invention will now be described in detail with reference to Figures 1 to 4. First, referring to Figure 1, a partial perspective view of the preform 20 of the aircraft bulkhead is shown. As the name suggests, a bulkhead is a frame that isolates different parts. As mentioned above, bulkheads are widely used in various aircraft, such as aircraft fuselages, missile bodies, and airborne pods. Their main function is to serve as a commonly used primary force-transmitting and load-bearing structure, supporting and fixing various components of the aircraft, such as an airplane, thereby stabilizing the overall structure of the aircraft and maintaining the shape of the aircraft, such as the fuselage. The preform of the bulkhead is an intermediate product in the manufacturing process of the bulkhead. After a series of subsequent processes, such as injection molding and curing, it finally forms the bulkhead. Therefore, the quality of the bulkhead mainly depends on the preform.

[0025] To withstand various stresses in different directions, textile fiber materials are extensively used in the preformed frame of the aircraft. These textile fibers, or yarns, are laid out in different directions to meet the stress requirements in different directions. As shown in Figure 1, the preformed body 20 mainly includes a web 22 and two edge strips 21. The two edge strips 21 are located at both ends of the preformed body 20, and the web 22 connects these edge strips 21 in the middle of the preformed body 20. This structure makes the cross-section of the preformed body 20 approximately C-shaped or Z-shaped. Figure 1 illustrates a preformed body 20 with a Z-shaped cross-section. Since most aircraft, such as aircraft fuselages and missile bodies, are cylindrical, the frames used to support the various parts of the fuselage and missile body are cylindrical in shape as a whole. This makes the preform of the frame have a certain curvature in the longitudinal direction L of its web plate 22. See Figure 2. It can be seen that the preform 20 has a curvature in the longitudinal direction L of its web plate 22. The 0-degree direction in Figure 2 is the longitudinal direction L of the web plate 22 of the preform 20.

[0026] Referring again to Figures 1 and 2, the web 22 of the preform 20 typically has a thickness of several millimeters, such as 1mm-5mm. Thus, the web 22 has an outer surface 25 and an inner surface 26. Since the preform 20 has a curvature in the longitudinal direction L of its web 22, the web 22 also has a corresponding curvature in that longitudinal direction L, resulting in different radii for the outer surface 25 and the inner surface 26 of the web 22. As mentioned above, the preform 20 is mainly composed of textile fibers, i.e., yarn. Specifically, during the manufacturing process of the preform 20, a large number of yarns are layered and laid out to form the web 22 and edge strips 21 of the preform 20. To meet the stress requirements of the preform 20 in all directions, the laid yarns must be under tension; otherwise, the yarns will lose tension when relaxed and will not be able to perform their functions of fixing, shaping, transmitting force, and bearing load on the preform 20.

[0027] Therefore, in order to form the web 22 of the preform 20, if yarns at a 0-degree angle relative to the longitudinal direction L (referred to as 0-degree yarns) are directly laid on the web 22 in the longitudinal direction L, multiple layers of 0-degree yarns of the same length will cause wrinkles on the inner surface 26 of the web 22 due to the different radii of the outer surface 25 and the inner surface 26. In other words, the 0-degree yarns on the inner surface 26 will become loose. For the reasons mentioned above, this is absolutely unacceptable.

[0028] For example, in the prior art, it is known to use a unidirectional tape to lay 0-degree yarn for forming the web 22. This unidirectional tape is made of multiple layers of 0-degree yarn of the same length, has a certain thickness, and its two sides are relatively flat before the web 22 is laid. However, after the web 22 is formed, wrinkles will appear on the inner side of the web 22 formed by this unidirectional tape due to the difference in the inner and outer radii of the web 22. Therefore, in the prior art, 0-degree yarn is not laid to form the web 22 of the preform 20. Instead, yarns are laid at other angles relative to the longitudinal direction L of the web 22 of the preform 20, such as 90 degrees or ±45 degrees. 0-degree yarn is only laid at the edge strip 21 of the preform 20 because the edge strip 21 has a nearly flat top surface 23 and bottom surface 24, meaning that the top surface 23 and bottom surface 24 of the edge strip 21 have almost no curvature. Therefore, in the prior art using unidirectional tape, the web 22 of the preform 20 does not have 0-degree yarn. This makes it impossible to meet the stress requirements of the web 22 of the preform 20 in the longitudinal direction L.

[0029] Existing technology also provides a known method for manually laying 0-degree yarn to form the web of a preform. To avoid wrinkles, this method involves dividing the 0-degree yarn into numerous short segments, manually laying each segment one by one, and then assembling them into a longer, complete web. Clearly, this method significantly increases the difficulty of manufacturing the preform, requires a large amount of time, leads to low manufacturing efficiency, and makes it difficult to guarantee quality and reliability.

[0030] To address the aforementioned problems, this invention proposes a method for manufacturing a preform 20 for an aircraft bulkhead. The method includes the following steps: laying a 0-degree yarn 7, stretched without wrinkles at a 0-degree angle relative to the longitudinal direction L, on the web 22 of the preform 20. The specific implementation of this invention will be described in detail below.

[0031] To achieve a wrinkle-free laying of 0-degree yarn 7 on the web 22, which has an arc along the longitudinal direction L of the preform 20, the 0-degree yarn 7 needs to be properly fixed. For this purpose, auxiliary yarns, or 90-degree yarns or angled yarns used as the next weaving layer, can be used. Referring to Figure 2, a 90-degree yarn refers to a yarn laid at a 90-degree angle relative to the longitudinal direction L of the web 22, i.e., perpendicular to the 0-degree yarn. When the angle formed by the laid yarn relative to the longitudinal direction L of the web 22 is neither 0 degrees nor 90 degrees, this yarn is called an angled yarn, such as a positive 45-degree yarn or a negative 45-degree yarn. It can be seen that 0-degree yarn, 90-degree yarn, and angled yarn refer to the angle formed relative to the longitudinal direction L of the web 22. The materials of these yarns can be, for example, carbon fiber, glass fiber, aramid fiber, etc. In contrast, the auxiliary yarn can be made of materials such as nylon hot melt yarn, which can melt under heat. Therefore, the auxiliary yarn serves to temporarily fix the 0-degree yarn 7 or angle yarn during the manufacturing process of the preform 20. In subsequent processes, the preform 20 is immersed in, for example, liquid resin. After the preform 20 is fully immersed in resin, it is removed from the liquid resin and cured. The 0-degree yarn or angle yarn is then fixed by the resin, at which point the previous auxiliary yarn can be melted away. The following section will describe how the 0-degree yarn is fixed and laid out, in conjunction with the method of laying the 0-degree yarn, thereby explaining the manufacturing method of the preform 20 in this invention.

[0032] The laying of the 0-degree yarn 7 can be achieved using a axial yarn system. A axial yarn refers to yarns whose extension direction is along the axial direction (longitudinal direction) of the mandrel 1, that is, towards the direction pulled by the clamping head 11 of the mandrel 1. This direction is the longitudinal direction L where the web 22 is located. Therefore, the axial yarn is the 0-degree yarn 7. Multiple individual 0-degree yarns 7 can be laid simultaneously. The spacing between these individual 0-degree yarns 7 can be set by adjusting the total number of 0-degree yarns 7, taking into account the width or thickness of the individual 0-degree yarns 7 and the cross-sectional perimeter of the mandrel 1.

[0033] To reduce yarn fiber interlacing and creasing, in the method according to the invention, the step of laying the 0-degree yarn 7 includes: when introducing the 0-degree yarn, auxiliary yarns 8 for fixing the 0-degree yarn 7 can be laid and woven on both sides of the 0-degree yarn 7, see Figure 4. As shown in Figure 4, a yarn carrier 3 and a bobbin tube 4 located between the yarn carriers 3 are installed on the braiding machine 5, and the braiding ring 2 of the braiding machine 5 is fixedly fitted on the mandrel 1, which is pulled along the forward movement direction F. In the method according to the invention, the step of laying the 0-degree yarn 7 further includes: drawing the 0-degree yarn 7 from the bobbin frame 6 of the bobbin system, and the 0-degree yarn 7 passing through the bobbin tube 4 installed on the braiding machine 5 and being led to the braiding ring 2 fitted on the mandrel 1; the 0-degree yarn 7 is led onto the mandrel 1 via the braiding ring 2 and pulled by the mandrel 1. An exemplary method of guiding the 0-degree yarn 7 is given here, which is a preferred embodiment when the braiding machine 5 is provided. However, the invention is not limited to this. Any other suitable method can be used to guide the 0-degree yarn 7 according to the invention.

[0034] Furthermore, based on the yarn carriers 3 provided on both sides of the yarn tube 4 on the braiding machine 5, in the method according to the invention, the step of laying the auxiliary yarn 8 includes: drawing the auxiliary yarn 8 from the yarn carriers 3 mounted on the braiding machine 5, and guiding the auxiliary yarn 8 to the braiding ring 2 on both sides of the 0-degree yarn 7 drawn from the yarn tube 4; guiding the auxiliary yarn 8 to the mandrel 1 via the braiding ring 2, and clamping and fixing the 0-degree yarn 7 to the mandrel 1 by the auxiliary yarn 8. Here, the auxiliary yarn 8 is located on both sides of the 0-degree yarn 7, which means that the auxiliary yarn 8 is clamped at an angle different from 0 degrees or 90 degrees relative to the longitudinal direction L of the web 22, i.e., relative to the 0-degree yarn 7. That is, in terms of the included angle, the auxiliary yarn 8 is similar to the angle yarn, but the materials of the two are different, as described above. Thus, the 0-degree yarn 7 and the auxiliary yarn 8 are interwoven with each other in this way and fixed to each other on the mandrel 1. Similarly, this is a preferred method of guiding the auxiliary yarn 8 when the braiding machine 5 is provided. In the presence of the braiding machine 5, it is preferable to use the braiding loop 2, which is part of the braiding machine 5, to lay the 0-degree yarn 7 and the auxiliary yarn 8. This makes full use of existing equipment resources and simplifies the process flow.

[0035] Of course, the present invention is not limited to this. In the absence of a weaving machine 5, the yarn laying can also be achieved by designing tooling. Specifically, the 0-degree yarn 7 and auxiliary yarn 8 are laid using a yarn spreader 14 of a contour-following yarn take-up device. The yarn spreader 14 has numerous yarn spreading holes through which the 0-degree yarn 7 and auxiliary yarn 8 pass, are evenly spread, and then guided to and directly adhere to the surface of the mandrel 1. Simultaneously, for example, a robot, under the traction of the gripping head 11, pulls the 0-degree yarn 7 and auxiliary yarn 8 onto the mandrel 1 forward along the forward movement direction F. The cross-sectional shape of the mandrel 1 depends on the part to be manufactured; for example, it can be circular or rectangular. Supported by the bracket 12, the mandrel 1 can be pulled forward along the forward movement direction F by the gripping head 11.

[0036] Besides using auxiliary yarn 8 to constrain and fix the 0-degree yarn 7, the next knitting layer of the 0-degree yarn, namely the 90-degree yarn 10 or the angle yarn 9, can also be used to constrain and fix the 0-degree yarn 7, as shown in Figure 3. In one embodiment of the invention, the laying of the 0-degree yarn 7 and the winding of the 90-degree yarn 10 can be performed simultaneously. That is, in the method according to the invention, the step of laying the 0-degree yarn 7 includes: wrapping and winding the 0-degree yarn 7 with the 90-degree yarn 10, which extends at a 90-degree angle relative to the longitudinal direction L of the web 22. In this case, the 0-degree yarn 7 laid on the mandrel 1 is wrapped and fixed by the 90-degree yarn 10. As the mandrel 1 is pulled forward along the forward movement direction F, the 0-degree yarn 7 is pulled forward by the mandrel 1, while the 90-degree yarn 10 wraps and winds around the 0-degree yarn 7, thereby fixing the 0-degree yarn 7 to the mandrel 1. Specifically, as shown in Figure 3, in the method according to the present invention, the step of laying the 90-degree yarn 10 further includes: drawing the 0-degree yarn 7 from the yarn carrier 6 to, for example, a yarn spreader 14 on the mandrel 1, and then drawing it onto the mandrel 1 through the yarn spreader 14; drawing the 90-degree yarn 10 from the winding machine 13, and similarly drawing it to, for example, the yarn spreader 14, and then drawing it onto the mandrel 1 through the yarn spreader 14, wherein the 0-degree yarn 7 is covered and fixed onto the mandrel 1 by the 90-degree yarn 10.

[0037] In another embodiment of the invention, the step of laying the 0-degree yarn 7 further includes weaving angle yarns 9 on both sides of the 0-degree yarn 7 at an angle different from 0 degrees or 90 degrees relative to the longitudinal direction L of the web 22. That is, the angle yarns 9 are used to fix the 0-degree yarn 7. For this purpose, the laying of the 0-degree yarn 7 can be carried out simultaneously with the weaving of the angle yarns 9. In this case, referring to FIG3 again, the 0-degree yarn 7 is on the inside, and the angle yarns 9 cover the 0-degree yarn 7. During the weaving process, the 0-degree yarn 7 is pulled forward by the mandrel 1, and the angle yarns 9 are woven outside the 0-degree yarn 7, fixing the 0-degree yarn 7 to the mandrel 1. Specifically, in the method according to the invention, the step of laying the angle yarn 9 further includes: drawing the 0-degree yarn 7 from the yarn carrier 6 and feeding it to the braiding ring 2 on the braiding machine 5, and then guiding it to the mandrel 1 after passing through the braiding ring 2; drawing the angle yarn 9 from the braiding machine 5 to the braiding ring 2 on both sides of the 0-degree yarn 7, and guiding it to the mandrel 1 after passing through the braiding ring 2, wherein the 0-degree yarn 7 is covered and fixed to the mandrel 1 by the angle yarn 9, thereby forming a two-dimensional triaxial woven fabric on the mandrel 1 (i.e., the 0-degree yarn 7 forming 0 degrees with respect to the longitudinal direction L of the web 22, the angle yarn 9 forming angles θ and -θ with respect to the longitudinal direction L, these three angular directions are called triaxial, and the angle θ here can be flexibly adjusted as needed). Thus, the 0-degree yarn 7 is held without bending in the middle of the angle yarn 9 without participating in the weaving. Since the braiding machine 5 is provided in this embodiment, it is preferable to use its braiding ring 2 to make the 0-degree yarn 7 and the angle yarn 9 spread out evenly.

[0038] Alternatively, according to the present invention, in order to use the angle yarn 9 to fix the 0-degree yarn 7, especially in the absence of a braiding machine 5, the step of laying the angle yarn 9 in the method according to the present invention further includes: drawing the 0-degree yarn 7 from the yarn bobbin 6 and leading it to the yarn spreader 14, then through the yarn spreader 14 and onto the mandrel 1; leading the angle yarn 9 to the yarn spreader 14 on both sides of the 0-degree yarn 7, then through the yarn spreader 14 and onto the mandrel 1, wherein the 0-degree yarn is covered and fixed onto the mandrel 1 by the angle yarn 9. Here, the yarn spreader 14 is used instead of the braiding ring 2 of the braiding machine 5, and its function is similar to that of the braiding ring 2, both being used to evenly spread the 0-degree yarn 7 and the angle yarn 9 and lead them to the mandrel 1. Of course, the present invention is not limited to the braiding ring 2 and the yarn spreader 14, and any other suitable method can be used to lay the 0-degree yarn in the present invention.

[0039] The 0-degree yarn 7 can be laid on the web 22 of the preform 20 in the manner described above. The method for manufacturing the preform 20 for an aircraft frame according to the present invention can further include laying the 0-degree yarn 7 on the edge strip 21 of the preform 20 in the same manner. That is, the 0-degree yarn 7 can be laid on the entire cross-section of the preform 20, including the web 22 and the edge strip 21, in the manner described above. Of course, since the edge strip 21 has no curvature in the longitudinal direction L of the web 22 and is almost a flat rectangular surface, the 0-degree yarn can also be laid on the edge strip 21 using a unidirectional tape method.

[0040] The above describes the method for laying 0-degree yarn. Besides 0-degree yarn, 90-degree yarn 10 and angle yarn 9 are often required during the manufacturing process of the preform 20. These are laid on the web 22 and / or edge strips 21 of the preform 20 to meet the stress requirements in the 90-degree direction and the corresponding angle direction. When using 90-degree yarn 10, a winding process is employed, using a winding machine 13 to smoothly and neatly wind the 90-degree yarn 10 onto the mandrel 1. During this process, the mandrel 1 moves forward, and simultaneously, the winding machine 13 drives the 90-degree yarn 10 to wind around the mandrel 1 along the cross-sectional edge of the mandrel 1, so that the 90-degree yarn is wound onto the mandrel 1. Since the longitudinal direction, or forward movement direction F, of the mandrel 1 is the extension direction of the 0-degree yarn, which is also the longitudinal direction L of the web 2, the 90-degree yarn 10 is wound onto the mandrel 1 perpendicular to its longitudinal direction through this winding method. The spacing between multiple 90-degree yarns 10 can be set by adjusting the winding speed of the winding machine 13 and the forward speed of the mandrel 1.

[0041] When using angle yarn, a braiding machine 5 is used to weave angle yarn 9 onto the mandrel 1, and then lay it on the web 22 and / or edge strip 21 of the preform 20. Specifically, the mandrel 1 passes through the braiding ring 2 of the braiding machine 5, or in other words, the braiding ring 2 is fitted onto the mandrel 1. The angle yarn 9, with respect to the forward movement direction F of the mandrel 1, is drawn onto the mandrel 1 via the braiding ring 2 at a corresponding angle θ, in cooperation with the auxiliary yarn 8. During this process, the auxiliary yarn 8, with respect to the forward movement direction F of the mandrel 1, is also drawn onto the mandrel 1 via the braiding ring 2 at a corresponding angle -θ. If the angle yarn 9's angle relative to the forward movement direction F of the mandrel 1 is -θ, then the angle of the auxiliary yarn 8 relative to the forward movement direction F of the mandrel 1 is θ. Here, angle yarn 9 is woven only in the angular direction it is in, i.e., unidirectional weaving, while the auxiliary yarn 8 temporarily fixes the angle yarn 9. During operation, multiple braiding spindles are arranged on the braiding ring 2. Angle yarn 9 and auxiliary yarn 8 are placed on different braiding spindles. These braiding spindles pull the angle yarn 9 and the auxiliary yarn 8 to rotate in opposite directions along the braiding ring 2. The aforementioned angle θ can be, for example, 45 degrees or other angles other than 0 degrees or 90 degrees. The magnitude of the angle θ can be changed by adjusting the movement speed of the braiding spindles in a matching manner with the forward movement speed of the mandrel 1, thereby satisfying the stress requirements in any angular direction.

[0042] According to another aspect of the invention, the invention also relates to a preform 20 for an aircraft bulkhead manufactured using the method described above. The preform 20 has edge strips 21 at both ends and a web 22 located in the middle of the preform 20 and connecting the edge strips 21. The web 22 has an arcuate shape in its longitudinal direction L. According to the invention, the web 22 has 0-degree yarn 7 extending without wrinkles at a 0-degree angle relative to the longitudinal direction L. According to one embodiment, the edge strips 21 are also covered with 0-degree yarn 7. The various embodiments and advantages described above with respect to the method for manufacturing a preform for a bulkhead according to the invention are also applicable to the preform for a bulkhead according to the invention, and will not be repeated here.

[0043] After laying the dry fibers (referred to as dry fibers as they are not yet impregnated with resin) such as 0-degree yarn 7, 90-degree yarn 10, and angle yarn 9, the preform 20 is shaped, for example, by impregnating it with liquid resin, removing it, and then curing it. Then, auxiliary yarns, such as hot-melt wire, are heated and melted away. Next, C-shaped, Z-shaped, or other cross-sections are achieved through cutting and flanging, completing the preparation of the preform 20. The prepared preform 20 contains yarns of various materials, such as nylon hot-melt wire, resin, and possibly materials such as metal, thus forming a composite material frame preform. Finally, through processes such as liquid molding and curing, the final frame part is obtained.

[0044] The preform of the partition frame and its manufacturing method according to the present invention can adapt well to the multi-corner slender shape of the partition frame, breaking through the geometric shape limitations of the partition frame. It can meet the requirements of various specimens with varying bending shapes or sample sizes, and can easily prepare irregularly shaped rods and tubes. Furthermore, the fibers in the preform 20 of the present invention are continuous, and no wrinkles appear on its web 22. The 0-degree yarn can maintain tension, allowing for the laying of two adjacent layers of 0-degree yarn. This results in good structural integrity, improved in-plane (i.e., within the same braided layer) mechanical properties, and smooth, neat arrangement of yarns on the mandrel without twisting. This solves the problem of fiber bending and laying in the fan-shaped web area and corner area of ​​the partition frame structure, while ensuring fiber angle and spacing. The fiber spacing is ≤1.5mm, and the fiber angle deviation is within ±5°. In addition, the present invention achieves efficient laying of 0-degree yarn on the preform 20 without manual laying, resulting in high preparation efficiency. It reduces the inconsistency and randomness of manual operation, leading to better quality consistency and higher reliability. This invention employs an integrated weaving process, which reduces material waste caused by prepreg or dry fiber layering and cutting, while also improving production efficiency.

[0045] Some embodiments of this application have been described for illustrative purposes, but this application is not limited to these embodiments. Many modifications and variations will also arise in those skilled in the art. Therefore, these embodiments were selected and described to better illustrate the principles and practical applications of this application and to enable those skilled in the art to understand its contents; that is, all modifications and variations made without departing from the spirit of this application will fall within the protection scope of this application as defined by the appended claims.

Claims

1. A method for manufacturing a preform (20) for an aircraft bulkhead, wherein, The preform (20) has edge strips (21) at both ends thereon and a web (22) in the middle of the preform (20) and connecting the edge strips (21), the web (22) having an arc in the longitudinal direction (L) of the web (22), characterized in that the method includes the following step: laying a 0-degree yarn (7) that is stretched without wrinkles at a 0-degree angle relative to the longitudinal direction (L) on the web (22).

2. The method according to claim 1, characterized in that, The method further includes: laying the 0-degree yarn (7) on the edge strip (21).

3. The method according to claim 1 or 2, characterized in that, The step of laying the 0-degree yarn (7) includes laying and weaving auxiliary yarns (8) on both sides of the 0-degree yarn (7) to fix the 0-degree yarn (7).

4. The method according to claim 3, characterized in that, The step of laying the 0-degree yarn (7) further includes: The 0-degree yarn (7) is drawn out from the yarn bobbin (6) and passed through the yarn bobbin tube (4) installed on the braiding machine (5) to the braiding ring (2) fitted on the core mold (1); The 0-degree yarn (7) is drawn onto the mandrel (1) via the braiding loop (2) and is pulled by the mandrel (1).

5. The method according to claim 4, characterized in that, The step of laying the auxiliary yarn (8) includes: The auxiliary yarn (8) is drawn out from the yarn carrier (3) installed on the braiding machine (5) and led to the braiding loop (2) on both sides of the 0 degree yarn (7); The auxiliary yarn (8) is guided to the mandrel (1) via the braiding loop (2), and the 0-degree yarn (7) is clamped and fixed to the mandrel (1) via the auxiliary yarn (8).

6. The method according to claim 1 or 2, characterized in that, The step of laying the 0-degree yarn (7) includes: wrapping the 0-degree yarn (7) with a 90-degree yarn (10) that extends at a 90-degree angle relative to the longitudinal direction (L) of the web (22).

7. The method according to claim 6, characterized in that, The step of laying the 90-degree yarn (10) further includes: The 0-degree yarn (7) is drawn from the yarn frame (6) through the yarn spreader (14) onto the core mold (1); The 90-degree yarn (10) is drawn from the winding machine (13) through the yarn spreader (14) onto the mandrel (1). The 0-degree yarn (7) is wrapped and fixed onto the core mold (1) using the 90-degree yarn (10).

8. The method according to claim 1 or 2, characterized in that, The step of laying the 0-degree yarn (7) further includes weaving angle yarn (9) on both sides of the 0-degree yarn (7) at an angle different from 0 degrees or 90 degrees relative to the longitudinal direction (L) of the web (22).

9. The method according to claim 8, characterized in that, The step of laying the angle yarn (9) further includes: The 0-degree yarn (7) is drawn from the yarn carrier (6) through the braiding ring (2) onto the core mold (1); The angle yarn (9) is drawn from the braiding machine (5) to the braiding loop (2) on both sides of the 0-degree yarn (7), and then drawn through the braiding loop (2) to the mandrel (1). The 0-degree yarn (7) is wrapped and fixed onto the core mold (1) using the angle yarn (9).

10. The method according to claim 8, characterized in that, The step of laying the angle yarn (9) further includes: The 0-degree yarn (7) is drawn from the yarn frame (6) through the yarn spreader (14) onto the core mold (1); The angle yarn (9) is drawn onto the core mold (1) through the yarn spreader (14) on both sides of the 0-degree yarn (7). The 0-degree yarn (7) is wrapped and fixed onto the core mold (1) using the angle yarn (9).

11. A preform (20) of an aircraft frame manufactured by the method according to any one of claims 1-10, the preform (20) having edge strips (21) at both ends thereon and a web (22) located in the middle of the preform (20) and connecting the edge strips (21), the web (22) having an arc in its longitudinal direction (L), characterized in that, The web (22) has a 0-degree yarn (7) that extends without wrinkles at a 0-degree angle relative to the longitudinal direction (L).

12. The preform according to claim 11, characterized in that, The edge strip (21) is covered with the 0-degree yarn (7).

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