A method for forming a rotary preform based on weft yarn bending

Abstract

This invention relates to the field of preform forming technology, and more particularly to a method for forming a rotary preform based on weft yarn bending. In this technical solution, each warp yarn to be wound is first pre-treated to obtain multiple reinforcing warp yarns with a matrix layer attached to their surface. This allows a preset first tension to be applied to each reinforcing warp yarn, ensuring that all reinforcing warp yarns are fully extended and flat against the surface of the rotary mandrel. It also provides low-damage forming (i.e., reducing damage during fiber forming) and effective protection for brittle high-performance fibers. Simultaneously, controlling the first tension to be greater than the second tension allows the reinforcing warp yarns to be flattened after each turn of weft yarn, ensuring that the weft yarn forms a bending path and the reinforcing warp yarns are located in the same layer. This results in a wound rotary preform with straight warp yarns and bent weft yarns, thus significantly improving the axial mechanical properties of the rotary preform.

Description

Technical Field

[0001] This invention relates to the field of preform forming technology, and in particular to a method for forming a rotary preform based on weft yarn bending. Background Technology

[0002] In fields such as aerospace and rail transportation, there is an increasing demand for high-performance composite rotating components (such as cylindrical shells and shaped tubes) with complex stress structures.

[0003] In the field of rotary fiber preform molding, processes such as 2.5D weaving and needle punching are typically relied upon. Although there has been some development in automated winding in recent years, the tension of warp and weft yarns is mostly controlled mechanically. This may lead to undesigned bending of the warp yarns in the diameter variation region, thus affecting the axial mechanical properties of the preform. At the same time, it has poor adaptability to brittle high-performance fibers such as quartz fiber and ceramic fiber, and is prone to damage during the molding process.

[0004] Therefore, there is an urgent need to provide a method for forming rotary preforms based on weft yarn bending to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method for forming a rotary preform based on weft yarn bending, which can improve the axial mechanical properties of the rotary preform and reduce the damage generated during the fiber forming process.

[0006] In a first aspect, embodiments of the present invention provide a method for forming a rotary preform based on weft yarn bending, comprising: Each warp yarn to be wound is pre-treated to obtain multiple reinforcing warp yarns with a matrix layer attached to the surface. Along the generatrix direction of the rotating core mold, a predetermined number of reinforcing warp yarns are laid flat on the surface of the rotating core mold, and a predetermined first tension is applied to each of the reinforcing warp yarns. Along the circumference of the reinforcing warp, a predetermined number of weft yarns are wound around the weave formed by the reinforcing warp, and a second tension is applied to each turn of the weft yarn; wherein, the first tension is greater than the second tension; After each turn of the weft yarn, the reinforcing warp yarn is flattened to form a curved path, so that the weft yarn forms a curved path and the reinforcing warp yarn is located in the same layer, resulting in a rotary preform with straight warp yarns and curved weft yarns.

[0007] Secondly, embodiments of the present invention provide a preform formed by winding using the method mentioned in the above embodiments.

[0008] Beneficial effects: According to the method for forming a rotary preform based on weft yarn bending provided in the embodiments of the present invention, firstly, each warp yarn to be wound is pre-treated to obtain multiple reinforcing warp yarns with a matrix layer attached to the surface. This allows a preset first tension to be applied to each reinforcing warp yarn, which not only allows all reinforcing warp yarns to fully extend and flatten against the surface of the rotary core mold, but also provides low-damage forming (i.e., reducing damage generated during fiber forming) and effective protection for brittle high-performance fibers. At the same time, by controlling the first tension to be greater than the second tension, the reinforcing warp yarns can be flattened after each turn of weft yarn winding, so that the weft yarn forms a bending path and the reinforcing warp yarns are located in the same layer, resulting in a rotary preform with straight warp yarns and bent weft yarns. This significantly improves the axial mechanical properties of the rotary preform. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 A schematic flowchart of the method for forming a rotary preform based on weft yarn bending provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the tensioner provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a conventional 2.5D rotating preform provided in an embodiment of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] like Figure 3As shown, the traditional 2.5D rotating precast structure features bent warp yarns and straight weft yarns. However, the bent warp yarns lead to a decrease in the axial performance of the rotating component. This is because traditional methods often increase or decrease the number of warp yarns to accommodate diameter changes, causing undesigned bending of the warp yarns in the diameter-changing region, resulting in a decrease in axial modulus and strength. This is particularly detrimental to brittle materials such as quartz fiber and ceramic fiber, as bending easily causes fiber damage. While organic fibers such as aramid and polyimide have better toughness, their fiber orientation deviates from the main force direction, reducing axial load-bearing efficiency.

[0013] To solve the above technical problems, such as Figure 1 As shown, this embodiment of the invention provides a method for forming a rotary preform based on weft yarn bending, including: Step S1: Perform surface pretreatment on each warp yarn to be wound to obtain multiple reinforcing warp yarns with a matrix layer attached to the surface. Step S2: Along the generatrix direction of the rotating core mold, lay a preset number of reinforcing warp yarns flat on the surface of the rotating core mold, and apply a preset first tension to each reinforcing warp yarn. Step S3: Along the circumference of the reinforcing warp, a predetermined number of weft yarns are wound around the weft yarns at the weft opening formed by the reinforcing warp, and a second tension is applied to each weft yarn; wherein, the first tension is greater than the second tension, and after each weft yarn is wound, the reinforcing warp is flattened to make the weft yarns form a curved path and the reinforcing warp yarns are located in the same layer, so as to obtain a rotating preform with straight warp yarns and curved weft yarns.

[0014] In this embodiment, each warp yarn to be wound is first pre-treated to obtain multiple reinforcing warp yarns with a matrix layer attached to their surface. This allows a preset first tension to be applied to each reinforcing warp yarn, ensuring that all reinforcing warp yarns are fully extended and flat against the surface of the rotating core mold. This also provides low-damage molding (i.e., reducing damage during fiber molding) and effective protection for brittle high-performance fibers. Simultaneously, controlling the first tension to be greater than the second tension allows the reinforcing warp yarns to be flattened after each turn of weft yarn, ensuring the weft yarn forms a curved path and the reinforcing warp yarns are in the same layer. This results in a rotating preform with straight warp yarns and curved weft yarns, thus ensuring the rotating preform is axially (or warp-wise, i.e.,...) Figure 3 The mechanical properties in the vertical direction (as shown) are significantly improved.

[0015] It should be noted that winding is a technology that uses dry fibers to create a three-dimensional preform through the synergy of textile technologies. Compared to weaving, it places greater emphasis on winding and weaving. In other words, winding is a forming process that combines winding and weaving, introducing continuous fibers or yarns into an interwoven yarn system and winding them along a mandrel or spatial path.

[0016] It should be noted that to obtain the rotary preform with straight warp and curved weft as claimed in this invention, two conditions must be met simultaneously: 1) each warp yarn to be wound is surface pretreated to obtain multiple reinforcing warp yarns; 2) the first tension is greater than the second tension (preferably, the first tension is at least three times the second tension). Otherwise, satisfying only one of these conditions will not yield the rotary preform with straight warp and curved weft as claimed in this invention.

[0017] For example, if only condition 1 is met, the following problems will exist: Since warp tension mainly controls the movement of warp yarns to achieve interweaving with weft yarns, and at the same time controls the shape of warp yarns to make them straight; while weft tension mainly controls the winding to achieve winding, and at the same time binds the warp yarns to the surface of the mandrel, and increases the density of the preform through tension; therefore, if the tension of warp and weft yarns is not controlled, the conformation requirements and the density requirements of the preform cannot be met. At the same time, the tension mismatch in the two directions will also lead to problems such as inconsistent yarn shape and poor density consistency.

[0018] For example, if only condition 2 is satisfied, the following problem will exist: Since the warp yarn is bound to the surface of the mandrel by the continuous winding of the weft yarn during the weaving process, the pressure of the weft yarn on the warp yarn can easily cause the warp yarn to bend; however, by simply increasing the warp yarn tension, the warp yarn still has the flexible characteristics, thus forming a structure that bends in both the warp and weft directions; therefore, by simply changing the warp yarn tension without performing surface reinforcement pretreatment on the warp yarn, it is not possible to achieve a structure with straight warp yarns and bent weft yarns.

[0019] It should also be noted that, considering that the rotary preform needs to be compatible with other matrices (such as resin and ceramic precursors) to obtain composite materials, the benefits of step S1 above can also include significantly improving the interfacial bonding strength between the rotary preform and the matrix, thereby significantly improving the overall performance of the composite material.

[0020] In one embodiment of the present invention, step S1 includes: Each warp yarn to be wound is completely immersed in the matrix, and each warp yarn after being immersed in the matrix is ​​heated and cured.

[0021] In one embodiment of the present invention, the matrix is ​​a resin or ceramic precursor solution.

[0022] In traditional processes, the preform and matrix are mostly mixed or impregnated, rather than directly impregnating each warp yarn to be woven with the matrix and then heating and curing each impregnated warp yarn. This is because the former directly produces a composite material, while the latter aims to enhance the structural strength of each warp yarn, thereby significantly improving the axial mechanical properties of the rotating preform and reducing damage during warp yarn forming. Furthermore, this invention does not limit the specific impregnation process (such as heating parameters and curing parameters), as long as it achieves surface reinforcement of the warp yarn.

[0023] In one embodiment of the present invention, the fibers used to reinforce the warp and weft yarns include at least one of high-performance fibers such as carbon fiber, quartz fiber, ceramic fiber, silicon carbide fiber, alumina fiber, aramid fiber, polyimide fiber, and basalt fiber.

[0024] In this embodiment, the fiber material used in the present invention has wide adaptability. Due to the surface reinforcement treatment of the warp fibers, it can be applied to various high-performance continuous fibers, including brittle high-performance fibers such as quartz fibers and ceramic fibers.

[0025] In addition, the fiber can also be a spreadable fiber. By controlling the warp and weft tensions, it can maintain its spreadable shape during the weaving process, avoiding shrinkage or clumping.

[0026] In one embodiment of the invention, the first tension is at least three times the second tension.

[0027] In this embodiment, applying a small or micro tension (i.e., a second tension) to the weft yarn enables independent design and precise control of the yarn arrangement density and straightness. This breaks through the limitations of tension coupling between warp and weft yarns in traditional weaving, allowing the warp and weft yarn shapes to be actively designed according to the stress requirements of different parts of the component, while ensuring that the warp yarns can be flat and adhere to the surface of the core mold under tension.

[0028] In one embodiment of the present invention, the rotating body component made of the rotating body preform includes a spacecraft reentry compartment, a rocket engine nozzle expansion section, an aero-engine casing, a wave-transparent antenna radome, and a diffuser cone section.

[0029] In one embodiment of the present invention, the tension control accuracy of both the warp and weft yarns is ±0.1cN / tex.

[0030] In this embodiment, the tension of each warp and weft yarn can be set and adjusted independently, thus meeting the differentiated needs of complex components.

[0031] In one embodiment of the present invention, the tension of both the reinforcing warp and weft yarns is controlled by tensioners 1, and each tensioner 1 controls the tension of one yarn.

[0032] In this embodiment, multiple independent electronic tensioners control the tension of each warp and weft yarn respectively, achieving precise setting and constant control of single yarn tension. The warp and weft tensions adopt completely independent control systems, which are coupled to each other through the control system. The tension adjustment range is wide and the control accuracy is high, which can meet the design difference requirements of warp and weft tensions.

[0033] like Figure 2 As shown, in one embodiment of the present invention, the tensioner 1 includes an electric cylinder 11, an inner ring 12, a friction plate 13 and an outer ring 14 arranged sequentially from the inside to the outside. The outer circumference of the outer ring 14 is used to wind the yarn. The outer ring 14 rotates relative to the inner ring 12. The electric cylinder 11 can change the friction between the inner ring 12 and the outer ring 14 by squeezing the friction plate 13, thereby changing the tension of the yarn.

[0034] In this embodiment, closed-loop control is mainly achieved by a tension sensor (not shown in the figure) monitoring the current tension value of the yarn in real time and feeding it back to the controller. The controller controls the electric cylinder 11 to precisely extend and retract according to a preset tension curve. The extension and retraction of the electric cylinder 11 changes the normal pressure of the friction plate 13 on the yarn, thereby actively changing the friction force and achieving stepless control of the yarn tension. Multi-level control is mainly achieved by connecting multiple tensioners in series along the yarn path to form a multi-level tension gradient control, gradually stabilizing the yarn tension to the target value and avoiding damage to the yarn from severe friction at a single point.

[0035] In addition, embodiments of the present invention also provide a preform formed by winding as described in any of the above embodiments.

[0036] It should be noted that the preform provided in this embodiment has the same inventive concept as the method embodiment described above, and therefore the two have the same beneficial effects. The beneficial effects of the preform will not be elaborated here.

[0037] The above technical solution will be described below through two specific embodiments.

[0038] Example 1 Example 1 provides a 2.5D rotating prefabricated body for a certain type of aero-engine housing, with an inner diameter of 650mm, an outer diameter of 680mm, and a generatrix length of 250mm, requiring excellent high-temperature resistance and interface bonding strength.

[0039] Fiber selection: Both warp and weft yarns are made of polyimide fiber with a linear density of 167 tex.

[0040] Molding process: Step 1: Warp yarn surface pretreatment. Using the EC150R resin system, the resin is kept below 90°C until it is completely liquefied. Each fiber is immersed in the resin bath, controlling the resin content to approximately 25%. Pre-curing is then performed at 150°C, achieving approximately 40% curing, forming a uniformly coated pre-cured layer. The pre-cured BMI resin layer has a similar chemical structure to the polyimide fiber, exhibiting good compatibility. During subsequent molding, the pre-cured layer co-cures with the fresh BMI resin, forming a chemically bonded interfacial transition zone.

[0041] Step 2: Design the parameters of the electronic tension control system. The warp tension control value is set to 7 cN / tex, and each warp yarn is controlled by an independent electronic tensioner; the weft tension is set to 0.6 cN / tex, and is kept constant by an electronic tensioner; the tension difference multiple is 11.7 times, and the tension control accuracy is ±0.1 cN / tex.

[0042] Step 3: Warp laying and setting. Lay 470 rows and 20 layers of warp yarns along the generatrix of the cone, keeping the number of yarns constant; the electronic tensioner of the warp tension control unit applies 7cN / tex tension independently to each warp yarn to ensure that each warp yarn is fully stretched, straight and in line with the mandrel surface; the pre-cured BMI resin partially cures under tension, keeping the warp yarns straight.

[0043] Step 4: Micro-tension continuous weft insertion. Set the weft tension to 0.6 cN / tex, and adjust it in real time using the electronic tensioner of the weft tension control unit. With each loop of weft yarn introduced, the warp yarn is flattened to conform to the shape, so that the warp yarns are in the same layer and the weft yarns form a curved path, forming a 2.5D rotating preform with straight warp yarns and naturally curved weft yarns.

[0044] Results: The preform produced has straight warp yarns and curved weft yarns, significantly improving warp load-bearing capacity. The pre-cured layer on the fiber surface forms a chemical bond interface with the matrix resin, and the interfacial shear strength is about 25% higher than that of the untreated sample.

[0045] Example 2 Example 2 provides a 2.5D rotating prefabricated body for the expansion section of a rocket engine nozzle. The component has an inlet diameter of 300mm, an outlet diameter of 600mm, and a generatrix length of 450mm. It is required to be resistant to high temperature, ablation, and have high axial load capacity.

[0046] Fiber selection: The warp yarn is made of carbon fiber (T700-12K), and the weft yarn is made of silicon carbide fiber (linear density 200tex).

[0047] Molding process: Step 1: Pretreatment of warp yarn surface. Using a polycarbosilane ceramic precursor system, each fiber is immersed in the precursor solution in a resin bath, with the precursor content controlled at approximately 20%. Heat treatment at 200℃ causes partial cross-linking of the precursor, forming a uniformly coated pre-ceramicized layer.

[0048] Step 2: Design the parameters of the electronic tension control system. The warp tension control value is set to 9 cN / tex, and each warp yarn is controlled by an independent electronic tensioner; the weft tension is set to 0.8 cN / tex, and is kept constant by an electronic tensioner; the tension difference multiple is 11.25 times, and the tension control accuracy is ±0.1 cN / tex.

[0049] Step 3: Warp laying and shaping. Lay 580 rows and 25 layers of warp yarns along the generatrix of the cone, gradually increasing the number of warp yarns from the top to the larger end; the electronic tensioner of the warp tension control unit applies 9cN / tex tension independently to each warp yarn to ensure that each warp yarn is fully stretched, straight and in line with the surface of the mandrel.

[0050] Step 4: Micro-tension continuous weft insertion. Set the weft tension to 0.8 cN / tex, and adjust it in real time using the electronic tensioner of the weft tension control unit. Each time a loop of weft yarn is introduced, the warp yarn is flattened to conform to the shape, so that the warp yarns are in the same layer and the weft yarns form a curved path, forming a 2.5D rotating preform with straight warp yarns and curved weft yarns.

[0051] Results: The preform produced has straight warp yarns and curved weft yarns. The pre-ceramicized layer on the warp yarn surface forms a good interface bond with the subsequent ceramic matrix. The warp modulus is increased by about 30% compared with the traditional 2.5D preform, and the ablation resistance is significantly improved.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for forming a rotary preform based on weft yarn bending, characterized in that, include: Each warp yarn to be wound is pre-treated to obtain multiple reinforcing warp yarns with a matrix layer attached to the surface. Along the generatrix direction of the rotating core mold, a predetermined number of reinforcing warp yarns are laid flat on the surface of the rotating core mold, and a predetermined first tension is applied to each of the reinforcing warp yarns. Along the circumference of the reinforcing warp, a predetermined number of weft yarns are wound around the weft yarn at the weft opening formed by the reinforcing warp, and a second tension is applied to each turn of the weft yarn; wherein, the first tension is greater than the second tension, and after each turn of the weft yarn is wound, the reinforcing warp yarn is flattened to make the weft yarn form a curved path and the reinforcing warp yarns are located in the same layer, resulting in a rotary preform with straight warp yarns and curved weft yarns.

2. The method according to claim 1, characterized in that, The surface pretreatment of each warp yarn to be wound includes: Each warp yarn to be wound is completely immersed in the matrix, and each warp yarn after being immersed in the matrix is ​​heated and cured.

3. The method according to claim 2, characterized in that, The matrix is ​​a resin or ceramic precursor solution.

4. The method according to claim 1, characterized in that, The reinforcing warp and weft yarns are made of at least one of carbon fiber, quartz fiber, ceramic fiber, silicon carbide fiber, alumina fiber, aramid fiber, polyimide fiber, and basalt fiber.

5. The method according to claim 1, characterized in that, The first tension is at least three times the second tension.

6. The method according to claim 1, characterized in that, The rotating body components made from the prefabricated rotating body include a spacecraft reentry compartment, a rocket engine nozzle expansion section, an aero-engine casing, a wave-transparent antenna radome, and a diffuser cone section.

7. The method according to claim 1, characterized in that, The tension control accuracy of both the reinforcing warp yarn and the weft yarn is ±0.1 cN / tex.

8. The method according to any one of claims 1-7, characterized in that, The tension of both the reinforcing warp yarn and the weft yarn is controlled by a tensioner, and each tensioner controls the tension of one yarn.

9. The method according to claim 8, characterized in that, The tensioner includes an electric cylinder, an inner ring, a friction plate, and an outer ring arranged sequentially from the inside to the outside. The outer ring is used to wind yarn around its outer periphery. The outer ring rotates relative to the inner ring. The electric cylinder can change the friction between the inner ring and the outer ring by squeezing the friction plate, thereby changing the tension of the yarn.

10. A precast body, characterized in that, The method described in any one of claims 1-9 is used for winding and forming.

Images