Three-dimensional braided preform and preparation method and preparation device thereof

Abstract

The invention belongs to the technical field of three-dimensional weaving, and relates to a three-dimensional woven preform and a preparation method and a preparation device thereof. The preparation device of the three-dimensional braided preform comprises a chassis, a plurality of casters, a plurality of driving plates and a plurality of braided yarn carriers, the braided yarn carriers comprise braided yarn carrier bases and braided yarn carrier straight rods, the casters, the driving plates and the braided yarn carrier bases are all multiple, the casters are six-notch circular plates, and the driving plates are two-notch circular plates. The preparation method of the three-dimensional braided preform adopts the preparation device of the three-dimensional braided preform. The three-dimensional braided preform is prepared by adopting the preparation method of the three-dimensional braided preform. Knitted joints on the surface of the prepared three-dimensional woven prefabricated body are distributed more uniformly, coherently and compactly, the surface concave-convex degree is relatively small, and a composite material prepared from the three-dimensional woven prefabricated body is stressed more uniformly when being subjected to an external load and is not prone to being damaged and losing efficacy quickly due to stress concentration.

Description

Technical Field

[0001] The present invention belongs to the technical field of three-dimensional weaving, and relates to a three-dimensional weaving preform and a preparation method and a preparation device thereof. Background Art

[0002] High-performance fiber-reinforced composites (FRPs) offer high strength, low density, high modulus, fatigue resistance, corrosion resistance, high-temperature resistance, and a low coefficient of thermal expansion, making them suitable alternatives to traditional metal materials. They are widely used as load-bearing structures in aerospace, transportation, wind power, pressure vessels, and other fields. Load-bearing structures are generally classified by geometry into three categories: rod structures, shell structures, and solid structures. Rod structures are characterized by their axial dimensions being much larger than their cross-sectional dimensions. They are relatively simple, easy to design and manufacture, and highly efficient. They are often produced using pultrusion processes and are ubiquitous in various equipment and facilities. Currently, the application of high-performance fiber composites in rod structures is primarily based on hollow rods, such as drone wing frames, drive shafts, and oil drill pipes. The use of solid composite rod structures is particularly necessary for large-scale cable-type, core-type, or rod-type components with complex load environments that hollow rod structures cannot meet. Examples include tension cables, composite cores for overhead lines, marine cable reinforcements, oil push rods, and composite cores for structural battery electrodes. However, solid round rod composites are currently mostly produced using pultrusion, pultrusion & winding, and pultrusion & braided tube processes. Most of the fibers within the composite are aligned parallel to the axial direction, resulting in insufficient static performance in directions other than the axial direction and virtually no dynamic performance. Furthermore, although the pultrusion & winding and braiding processes include a winding or braided tube layer enclosing the axial fibers, this creates a "skin-core" structure, making it difficult for the "skin" layer to effectively restrain crack propagation within the "core" structure, resulting in poor dynamic performance.

[0003] A 3D braided preform is a monolithic structure formed by interlocking fibers in space. It exhibits a non-stratified nature. The braided knots within the preform effectively physically block crack propagation, enhancing the dynamic performance of the composite material. This preform allows the composite material to achieve both static and dynamic performance. Therefore, rod-type composites molded from 3D braided preforms are expected to address many of the issues facing the aforementioned skin-core composite materials.

[0004] Patent CN114990778B discloses a three-dimensional braided preform, the structure of which is as follows: Figure 1 As shown, the preparation method is as follows: three-cut corner wheels are arranged to intersect with each other, and yarn storage spindles are arranged on the yarn carriers of the corner wheels respectively, so that the three-cut corner wheels intersecting with each other move in opposite directions, and continuous weaving is obtained in this way. This preparation method has the following technical problems:

[0005] (1) The three-dimensional braided preform is affected by the forming mechanism, and its outline is an "I-shaped" or "rectangular" shape with an angular structure. When the composite material is subjected to external loads, stress concentration occurs at the corners and it is quickly damaged and fails.

[0006] (2) Due to the limitations of the design and layout of the angle wheels, the 3D braided preform cannot be formed into a round rod-shaped structure, and the structure cannot be scaled proportionally;

[0007] (3) The structural designability of the three-dimensional braided preform is not strong. The entire three-dimensional braided preform structure cannot realize independent control of the presence or absence of braided nodes, and it is impossible to perform differentiated structural and performance design within a single three-dimensional braided preform.

[0008] (4) The 3D braided preform has fewer braided nodes and uneven surface distribution. Since there is no advantage of tight interlocking of multiple layers, and there are two structural holes in the center of the structure due to the gap between the corner wheels, the overall structure of the 3D braided preform is relatively loose, the fiber content is not high, and the static and dynamic properties of the resulting composite material are insufficient.

[0009] The above problems hinder the application of three-dimensional braided preforms in forming round rod composite materials. Therefore, it is necessary to develop a new three-dimensional braided preform to solve the above problems. Summary of the Invention

[0010] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a three-dimensional braided preform and a preparation method and a preparation device thereof.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A preparation device for a three-dimensional braided preform comprises a chassis, an angle wheel, a dial and a braiding yarn carrier, the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, each braiding yarn carrier has a matching braiding yarn spindle and a braiding yarn unwinding auxiliary frame, the porcelain eye on the braiding yarn unwinding auxiliary frame can be made of aluminum oxide, preferably titanium oxide, which can reduce the friction coefficient and minimize carbon fiber wear. When in use, the yarn is first wound onto the braiding yarn spindle, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are concentrically assembled to the braiding yarn carrier straight rod of the matching braiding yarn carrier, and then the yarn on the braiding yarn spindle is passed through the porcelain eye on the side of the braiding yarn unwinding auxiliary frame for bundling. The number of the angle wheel, the dial and the braiding yarn carrier base are all multiple, the angle wheel is a six-cut circular plate, and the dial is a two-cut circular plate;

[0013] The six-notch circular plate is formed as follows: six regions a of identical shape and size are selected on the circular plate u, which are evenly distributed around the central circumference of the circular plate u and do not overlap with each other. The regions a are surrounded by two arcs, one of which coincides with the edge of the circular plate u. The six regions a are removed to form six notches, resulting in a six-notch circular plate.

[0014] The process of forming a two-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other, and are evenly distributed around the central circumference of the circular plate u. The regions b are surrounded by two arcs, one of which coincides with the edge of the circular plate v. After removing the two regions b to form two cuts, a six-cut circular plate is obtained.

[0015] The shape and size of area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0016] All six-slit circular plates are distributed in n layers, where n ≥ 2. Each layer is numbered starting from 1 from the inside out. The number of six-slit circular plates in the first layer is 1, and the number of six-slit circular plates in the i-th layer is 6 × (i-1), where 2 ≤ i ≤ n. Any two adjacent six-slit circular plates are arranged with a spacing of 1. The six-slit circular plates in the i-th layer are evenly distributed, and the lines connecting their centers form a regular hexagon. The vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the six lines radiating outward from the center point of the six-slit circular plate in the first layer.

[0017] Each cut of the six-cut circular plate is filled with a braided yarn carrier base; any two adjacent six-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are simultaneously filled with two cuts of a two-cut circular plate.

[0018] The preparation device of the three-dimensional braided preform of the present invention is different from the ordinary tube-sleeve braiding machine. The path of each braiding yarn carrier of the preparation device of the three-dimensional braided preform of the present invention can be freely changed in the inner and outer circles, so that the braiding yarn carrier can move between different circles to form a three-dimensional braided preform with consistent inner and outer surfaces. The interior of the ordinary tube-sleeve braiding machine is hollow in a large range and only has two yarn interweaving movements. The braiding yarn carrier moves in an 8-shaped trajectory in the track to weave the hollow tube-sleeve preform, such as Figure 19 As shown;

[0019] The present invention uses a combination of a six-cut circular plate-shaped angle wheel and a two-cut circular plate-shaped dial. The angle wheel and the dial are arranged in a hexagonal pattern. Due to the influence of the forming mechanism, the cross-section of the three-dimensional braided preform is characterized by quasi-circular symmetry. After the tension is released, the three-dimensional braided preform relaxes and its outer contour is approximately rod-shaped. There are no angular structures that cause stress concentration. This can effectively solve the technical problem of CN114990778B, which causes stress concentration and rapid damage and failure of composite materials under load due to the presence of angular structures.

[0020] The corner wheel layout of the present invention is that six corner wheels are evenly distributed around the circumference of one corner wheel, and any two adjacent corner wheels do not intersect, so that the structure of the three-dimensional braided preform can be proportionally enlarged. After proportional enlargement, the structural forming mechanism and performance mechanism of the three-dimensional braided preform are consistent, and the performance is significantly improved. This can solve the technical problem that the preform structure of CN114990778B cannot be proportionally enlarged.

[0021] like Figure 18 As shown, the cooperative movement of the dial and the angle wheel of the present invention enables the yarn 1 to form a braiding node 2. The independently controllable dial and angle wheel allow the braiding node 2 in the three-dimensional braided preform to be freely controlled to be present or absent, thereby enriching the designability of the three-dimensional braided preform structure, and being able to provide a differentiated design of the structure and performance of a single three-dimensional braided preform, thereby solving the technical problem of the CN114990778B preform that it is impossible to perform differentiated design of the structure and performance within a single three-dimensional braided preform.

[0022] As the preferred technical solution:

[0023] As described above, a preparation device for a three-dimensional woven preform is provided with a lining yarn carrier on at least one corner wheel; each lining yarn carrier has a matching lining yarn spindle and a lining yarn withdrawal auxiliary frame, and the porcelain eye on the lining yarn withdrawal auxiliary frame can be made of aluminum oxide, preferably titanium oxide. When in use, the yarn is first wound onto the lining yarn spindle, and then the lining yarn spindle and the lining yarn withdrawal auxiliary frame are concentrically assembled to the lining yarn carrier straight rod of the matching lining yarn carrier, and then the yarn on the lining yarn spindle is passed through the porcelain eye on the side of the lining yarn withdrawal auxiliary frame for bundled; when the preparation device of the present invention is used to prepare a three-dimensional woven preform, the woven knots all appear at the dial position, and the area of ​​the non-woven yarn carrier on the corner wheel will be missing yarn, which is manifested as holes in the woven structure of the cross-section of the three-dimensional woven preform. In order to fill the holes, the present invention adds a lining yarn carrier, and the axial lining yarn can be filled into the holes of the three-dimensional woven preform through the lining yarn carrier, thereby increasing the fiber volume content and strengthening the axial mechanical properties of the three-dimensional woven preform.

[0024] The device for preparing a three-dimensional braided preform as described above is provided with a lining yarn carrier on the corner wheel, the number of the lining yarn carrier is 1, and the lining yarn carrier is located at the center of the corner wheel.

[0025] As described above, a preparation device for a three-dimensional braided preform is provided with an angle wheel provided with lining yarn carriers, the number of the lining yarn carriers is greater than 1, and the lining yarn carriers are distributed in a circle around the central axis of the angle wheel.

[0026] As described above, a preparation device for a three-dimensional woven preform is provided, and a circular slide is also provided on the corner wheel provided with a lining yarn carrier, the center of the circular slide is located on the central axis of the corner wheel, and the lining yarn carrier is slidably connected to the circular slide, so that when the corner wheel rotates, the fibers on the lining yarn carrier will not follow the rotation of the corner wheel to generate torque to the greatest extent, and the straight bundles of multiple fiber bundles will be kept without twisting to the greatest extent. Specifically, the lining yarn carrier includes a lining yarn carrier base and a lining yarn carrier straight rod. The lining yarn carrier base is circular in shape, and ball bearings are embedded in the circumference and bottom surfaces. With the help of lubricating grease, the lining yarn carrier base can achieve smooth sliding on the circular slide, and the corner wheel provided with the lining yarn carrier is also provided with a circular through hole, which is used for the lining yarn carrier straight rod to pass through, and the diameter of the circular through hole is smaller than the width of the circular slide, so that the lining yarn carrier can be prevented from separating from the corner wheel.

[0027] As described above, a preparation device for a three-dimensional woven preform is provided, in which each angle wheel has a matching angle wheel driving motor, each dial has a matching dial driving motor, a pair of rollers is provided above the woven yarn carrier, and a winding wheel is provided above the pair of rollers; when in use, during the process of winding the yarn, the angle wheel moves under the control of the angle wheel driving motor, and the dial moves under the control of the dial driving motor, causing the woven yarn carrier and its matching woven yarn spindle and woven yarn unwinding auxiliary frame (or, there is also a lining yarn carrier and its matching lining yarn spindle and lining yarn unwinding auxiliary frame) to move together with it; after the yarn is bundled, it first passes through a pair of rollers, which have radial supporting elastic force, which can generate a certain clamping force on the bundled yarn to prevent the yarn bundle from loosening, and then the yarn bundle is wound around the winding wheel for a certain number of times according to the rotation direction of the winding wheel and then fixed, and the tension of the three-dimensional woven preform can be controlled by adjusting the weaving speed and the speed of the winding wheel, so that the three-dimensional woven preform can always remain straightened, formed and wound during the weaving process.

[0028] As described above, a preparation device for a three-dimensional braided preform is provided with a metal bunching ring above the braiding yarn carrier, and the metal bunching ring is located below a pair of rollers and is grounded. Specifically, the bunching ring can be made of stainless steel and can be embedded in a metal frame, which is connected to the metal body of the preparation device and shares a grounding device. The yarn can pass through the bunching ring before passing through the pair of rollers. The bunching ring not only ensures the yarn bundling effect and prevents the fibers from falling apart and getting entangled, but also conducts the static electricity generated by the friction of the fibers. The static electricity will cause the fibers to swell, accelerate the weaving damage, and affect the performance of the composite material.

[0029] A device for preparing a three-dimensional braided preform as described in any one of the above items (denoted as device A), wherein n>2;

[0030] For the cuts in each six-cut circular plate of the nth layer that are not opposite to other cuts, the braiding yarn carrier base in each cut is filled with one cut of a two-cut circular plate, and the other cut of the two-cut circular plate is filled with another braiding yarn carrier base.

[0031] A device for preparing a three-dimensional braided preform as described in any one of the above items (denoted as device B), wherein n=2;

[0032] In each six-notch circular plate of the nth layer, the number of notches that are not opposite to other notches is 3, which are respectively recorded as notch a, notch b and notch c, and notch b is located between notch a and notch c;

[0033] The braiding yarn carrier base in the incision a is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base, and the two-incision circular plate is marked as dial a;

[0034] The braiding yarn carrier base in the incision b is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base. The braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-incision circular plate is recorded as dial b;

[0035] The braiding yarn carrier base in the incision c is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base. The two-incision circular plate is marked as dial c.

[0036] A device for preparing a three-dimensional braided preform as described in any one of the above items (denoted as device C), wherein n=2;

[0037] In each six-notch circular plate of the nth layer, the number of notches that are not opposite to other notches is 3, which are respectively recorded as notch a, notch b and notch c, and notch b is located between notch a and notch c;

[0038] The braiding yarn carrier base in the incision a is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base, and the two-incision circular plate is marked as dial a;

[0039] The base of the braided yarn carrier in the cutout b does not fill one cutout of a two-cutout circular plate;

[0040] The braiding yarn carrier base in the incision c is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base. The two-incision circular plate is marked as dial c.

[0041] The present invention also provides a method for preparing a three-dimensional braided preform, which uses a preparation device for a three-dimensional braided preform as described above (i.e., device A or B). The specific process is: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction and all the dials are alternately controlled to rotate 180° in the same direction at the same time, and the rotation directions of the angle wheels and the dials are controlled to be opposite. A certain braiding angle is set as required for weaving. After multiple cycles, a three-dimensional braided preform is obtained; wherein, the angle wheels and the dials rotate in opposite directions so that the yarns carried by all the yarn carriers are intertwined, overlapped, and interlocked with each other in the space at the dials to form braided nodes in the three-dimensional braided preform. The angle wheels and the dials move alternately once to form a minimum braiding unit cross-section of the three-dimensional braided preform. The braiding nodes in this cross-section are distributed according to the layout position of the dials, and the inner and outer circle braiding nodes are interlocked as a whole. When the angle wheels and the dials move alternately repeatedly, the minimum braiding unit cross-section grows according to a certain rule to form a three-dimensional braided preform of a certain length.

[0042] The present invention also provides a method for preparing a three-dimensional woven preform, which uses a preparation device for a three-dimensional woven preform as described above (i.e., device B). The specific process is: after controlling all yarn carriers except the woven yarn carrier b to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, all the dials except the dial b are rotated 180° at the same time, the rotation directions of the dial a and the dial c are controlled to be opposite (so that the surface texture of the three-dimensional woven preform can be more uniform and smooth), and the rotation directions of the other dials and angle wheels except the dials a~c are opposite. After multiple cycles, the three-dimensional woven preform is obtained.

[0043] The present invention also provides a method for preparing a three-dimensional woven preform, using a preparation device for a three-dimensional woven preform as described above (i.e., device C). The specific process is: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are rotated 180° at the same time. The rotation directions of dial a and dial c are controlled to be opposite (so that the surface texture of the three-dimensional woven preform can be more uniform and smooth). The rotation directions of the other dials and angle wheels except dial a and dial c are opposite. After multiple cycles, a three-dimensional woven preform is obtained. The three-dimensional woven preform prepared by this method has a more rounded outline, and the angular structure is further weakened or even disappears.

[0044] As the preferred technical solution:

[0045] A method for preparing a three-dimensional braided preform as described in any of the above items, wherein the yarn is carbon fiber yarn, the ambient temperature is 20-25°C, and the relative humidity is 60-70%, thereby improving the smoothness of the braiding of the carbon fiber yarn and reducing the probability of fuzzing and broken yarns; the braiding yarn carrier corresponding to the braiding yarn carrier base filling the cutouts of the six-cut circular plates in the 1st to n-1st layers is recorded as braiding yarn carrier X, and the other braiding yarn carriers are recorded as braiding yarn carrier Y, and the diameter of the yarn carried by the braiding yarn carrier X is greater than the diameter of the yarn carried by the braiding yarn carrier Y, thereby improving the stiffness of the internal braiding node, which is beneficial to supporting the overall contour of the three-dimensional braided preform, while reducing the concave and convex feeling of the braiding node, so that the surface of the three-dimensional braided preform is relatively more conformable.

[0046] The present invention also provides a three-dimensional woven preform, which is prepared by a preparation method of a three-dimensional woven preform as described in any of the above items, and has an n-layer structure, each layer is numbered from 1 from the inside to the outside, the i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braiding nodes, 2≤i≤n, and when the preparation device also includes a lining yarn carrier, in the structure of the three-dimensional woven preform, the holes between the i-th layer and the i-1-th layer and some or all of the braiding nodes are filled.

[0047] Compared with existing fiber structures such as fiber parallel body, fiber winding body, fiber braided tube body, fiber felt body, etc. (existing fiber structures such as Figure 22 Compared with the three-dimensional braided preform of the present invention, the yarns are regularly distributed in the radial direction, the axial direction and other spatial directions between the two, and are a spatially integrated structure. The yarns are interlaced / overlapped / interlocked with each other in space to form an axially extended overall structure. In the cross-sectional direction, it is a solid-like structure that is overall coherent and does not have structural stratification. Figure 15 As shown, the number of inner rings 3 / middle rings 4 / outer rings 5, the thickness of the rings and the size of the holes between the rings can be controlled by adjusting the weaving process and yarn specifications. These macroscopic ring structures are obtained by regularly combining a series of yarn weaving nodes. The number and position distribution of each weaving node of the three-dimensional weaving preform of the present invention can be freely designed. Each weaving node forms a spatial constraint on the interlocking multiple yarns, effectively suppressing the tendency of yarn volume expansion and contraction, disrupting the diffusion path of microcracks, and effectively alleviating the tendency of microcracks to extend and damage quickly along a long path in a certain direction, so that the cracks can be quickly stagnated within a shorter path. Figure 18 The different colored rods in the figure represent the yarns of each path. The yarns bend and extend axially while also penetrating the entire structure of the 3D braided preform laterally. The holding force from the outside to the inside provided by the numerous braided nodes is evenly distributed on the 3D braided preform. The overall structural integrity of the 3D braided preform is far superior to that of other skin-core layered structures or the chopped fiber structures of random mats. The 3D braided preform of the present invention has a very significant effect in suppressing structural delamination.

[0048] Compared with existing three-dimensional laminated preforms, three-dimensional orthogonal braided preforms, and 2.5D preforms, the three-dimensional braided preform of the present invention is a three-dimensional integral structure that is radially self-closed and axially infinitely extendable. Except for the yarn breaks in the axial section, there are no additional broken sections, no auxiliary edge sealing is required, and no additional process issues such as the number of layers, laying direction, warp and weft yarns, and Z-direction bundling yarns are involved.

[0049] Compared with the three-dimensional four-way braided preform (four-step three-dimensional braiding), the three-dimensional braided preform of the present invention is different in that: (1) the braiding yarns of the three-dimensional four-way braided preform are arranged in a matrix in the form of rows and columns, and each braiding yarn moves alternately along the rows and columns under the drive of the yarn carrier (such as Figure 20 and Figure 21As shown in the figure), any braiding node of the three-dimensional braided preform of the present invention can be freely designed to be present or not and to be positioned, and the path of the yarn from the outside to the inside can be freely designed, which has a higher degree of design freedom and realizes the local design of mechanical properties. For example, the dense and sparse distribution of braided nodes can be continuously changed. At this time, the bending resistance, shear resistance, impact resistance and other properties at different positions will be different, and its outer contour can be arbitrarily changed based on this feature; (2) The structure of the three-dimensional four-way braided preform is relatively simple, and is limited by the matrix row and column motion principle of the four-step yarn carrier. The basic motion trajectory is mostly the overall lateral and longitudinal movement of a group of yarn carriers, which seriously limits the flexibility of the structural design within a row and the internal and external structure of the preform. The density distribution of the structure is differentiated, and the outline of the obtained preform is mainly a square solid outline. The four edges and corners of the preform are clear, and the bending degree of the yarn at the edges and corners is large, which is the main stress failure point when the preform is used. The shape outline of the preform is relatively simple; the three-dimensional woven preform structure of the present invention has a high degree of freedom in design, and can be designed to have dense arrangement of the outer ring braiding nodes and sparse arrangement of the inner ring braiding nodes, but there are still yarns evenly running through the two ring structures to make them a whole; (3) The braiding nodes in the three-dimensional four-way braided preform need to be generated or disappeared at the same time in both the horizontal and vertical columns, and any braiding node in the three-dimensional woven preform structure of the present invention can be independently realized to be present or absent, for example For example, in a preform, it is necessary to achieve high tensile strength in one part of the structure and high bending strength in another part at the same time, while the surface structure can still remain consistent. However, the three-dimensional four-way braided preform cannot achieve this function because its internal and external structures cannot be independently designed and formed. The three-dimensional braided preform structure of the present invention only needs to design the same surface braiding trajectory, reduce the number of braiding nodes in the part with high tensile strength, increase the braiding pitch distribution, increase the number of braiding nodes in the part with high bending strength, and reduce the braiding pitch distribution, so as to achieve this; (4) The three-dimensional four-way braided preform does not reserve a position for the axial lining yarn that does not participate in the braiding, and needs to sacrifice part of the yarn carrier in the braiding trajectory to fix it. Axial lining yarns: The thickness of the axial lining yarns will seriously affect the mechanical properties of the overall structure. At the same time, these lining yarns will be skewed and bent due to the movement of the weaving yarns, and the enhancement effect of their axial tensile properties will be affected. The three-dimensional woven preform of the present invention naturally leaves axial lining yarn space in the axial direction. Even if the lining yarns are relatively thick, the impact on the weaving yarn structure will be very limited; (5) The three-dimensional woven preform structure of the present invention has excellent profiling ability of the overall structure because of the independent design characteristics of each weaving node. It can approach the net size molding target contour structure (such as products with different thicknesses and cross-sections, products with large cross-sectional shapes) to the greatest extent, while the profiling ability of the three-dimensional four-way woven preform is very limited.

[0050] Beneficial effects:

[0051] (1) The three-dimensional braided preform of the present invention has the characteristic of circular symmetry in cross section. The braided nodes on the surface of the three-dimensional braided preform are more evenly distributed, coherent and dense, and the surface unevenness is relatively smaller. Therefore, the composite material prepared from the three-dimensional braided preform is subjected to relatively more uniform stress when subjected to external loads, and is not easily damaged and failed quickly due to stress concentration. However, the cross section of the preform in CN114990778B can only show symmetry along the X / Y axis, with obvious angular structures, a small number of braided nodes, and a sparse distribution, resulting in a lack of surface structure. As a result, the mechanical properties of the composite material prepared from the preform are limited.

[0052] (2) The cross-sectional structure of the three-dimensional braided preform of the present invention can be enlarged proportionally and can be gradually enlarged proportionally according to the target requirements. The enlarged preform structure is consistent with the initial structure in layout and has stable and consistent performance; while the cross-sectional structure of the three-dimensional braided preform in CN114990778B Figure 6 and Figure 24 The structure cannot be enlarged proportionally, or the structural shortcomings will also be magnified when it is enlarged.

[0053] (3) The braiding nodes of the three-dimensional braided preform of the present invention can be independently designed to be present or absent, which enriches the design types of the preform structure and can realize the differentiated design of the structure and performance of different parts in a single preform. However, the braiding equipment in CN114990778B only has corner wheels but no dials, and the structure of the resulting preform cannot realize the independent control of the presence or absence of braiding nodes. For example, when the control of a corner wheel stops working, the preform structure will be incomplete and cannot complete continuous braiding and forming.

[0054] (4) The number of braided knots and yarn content of the three-dimensional braided preform of the present invention are significantly greater than those in CN114990778B. Figure 6 and Figure 24 The number of braided nodes and yarn content of the structure, the three-dimensional braided preform of the present invention relies on a large number of braided nodes to be tightly interlocked from the inside out, so that the multi-layer yarn forms a denser overall non-layered structure, and the surface braided nodes of the three-dimensional braided preform are relatively evenly distributed, which reduces the surface structural defects of the three-dimensional braided preform and is conducive to improving the static and dynamic mechanical properties of the composite material. At the same time, the three-dimensional braided preform of the present invention can freely add axial lining yarns at the holes to further improve the mechanical properties of the three-dimensional braided preform, while the three-dimensional braided preform of CN114990778B Figure 6 and Figure 24 The yarn carrier cannot be arranged at the hole in the hole, resulting in the inability to add lining yarn to the hole. Therefore, it is different from the method of CN114990778B. Figure 6 and Figure 24 Compared with the preform shown in the figure, the three-dimensional braided preform of the present invention has improved axial tensile performance due to the axial lining yarn, and the impact resistance is improved because the structure from the inside to the outside is highly integrated and dense. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of a three-dimensional braided preform in the prior art;

[0056] Figure 2 is a schematic diagram of a device according to embodiment A1 of the present invention;

[0057] Figure 3 This is a schematic diagram of the weaving-bundling-winding process of the three-dimensional braided preform of the present invention;

[0058] Figure 4 Schematic diagram of weaving using a device according to Example A6; in the figure, seven corner wheels move simultaneously clockwise, while all dials rotate in the opposite direction to the corner wheels. Fibers along all routes interlace, overlap, and interlock within the spaces at the dials to form braided knots.

[0059] Figure 5 for Figure 4 A physical picture of a three-dimensional braided preform produced by the production device shown;

[0060] Figure 6 for Figure 7 An axial view of the three-dimensional braided preform shown;

[0061] Figure 7 Schematic cross-sectional view of the unfilled hollow core of the three-dimensional braided preform of the present invention;

[0062] Figure 8 This is a schematic cross-sectional view of a three-dimensional braided preform of the present invention in which only a portion of the hollow core is filled;

[0063] Figure 9 This is a schematic cross-sectional view of a three-dimensional braided preform of the present invention with the hollow core fully filled; Figure 8 、 Figure 9 In the figure, the black circle indicates the axial lining yarn, and the size of the black circle indicates the thickness of the lining yarn;

[0064] Figure 10 A diagram showing the motion trajectory of the yarn when the device for preparing a three-dimensional braided preform of the present invention is used;

[0065] Figure 11 Schematic diagram of an angle wheel with a circular slide rail and a circular through hole in the apparatus for preparing a three-dimensional braided preform according to the present invention; in the figure, the black dot indicates the position of the lining yarn carrier;

[0066] Figure 12 It is a cross-sectional schematic diagram of a lining yarn carrier base containing a circular slide rail in the device for preparing a three-dimensional braided preform of the present invention;

[0067] Figure 13 Schematic diagram of a single lining yarn carrier in the apparatus for preparing a three-dimensional braided preform of the present invention; in the figure, the sphere on the thickness surface of the lining yarn carrier represents a ball;

[0068] Figure 14 is a schematic diagram of a device according to embodiment A4 of the present invention;

[0069] Figure 15 Schematic cross-sectional view of a three-dimensional braided preform when the corner wheels are three-layered in the device for preparing a three-dimensional braided preform of the present invention;

[0070] Figure 16 Schematic diagram of the structure of the spindle in the device for preparing the three-dimensional braided preform of the present invention;

[0071] Figure 17 Schematic diagram of the structure of the yarn withdrawal auxiliary frame in the preparation device of the three-dimensional braided preform of the present invention;

[0072] Figure 18 A braided section of a three-dimensional braided preform of the present invention and an enlarged schematic diagram thereof;

[0073] Figure 19 This is a figure-8 motion trajectory diagram of yarn in a conventional tube braiding machine in the prior art;

[0074] Figure 20 Schematic diagram of the principle of the four-step three-dimensional weaving method of the prior art; in the figure, x represents the horizontal direction, x' represents the 45° direction of x counterclockwise, y represents the vertical direction of x, and y' represents the 45° direction of y counterclockwise;

[0075] Figure 21 Schematic diagram of the steps of the four-step three-dimensional weaving method in the prior art; in the figure, a is the initial state of the four-step three-dimensional weaving method, b is a schematic diagram of the first step of the four-step three-dimensional weaving method, c is a schematic diagram of the second step of the four-step three-dimensional weaving method, d is a schematic diagram of the third step of the four-step three-dimensional weaving method, and e is a schematic diagram of the fourth step of the four-step three-dimensional weaving method;

[0076] Figure 22 Schematic diagram of the existing fiber structure; in the figure, a is a parallel fiber body, b is a twisted fiber body, c is a braided fiber body, and d is a fiber felt body;

[0077] Figure 23 is a schematic diagram of a device according to embodiment A7 of the present invention;

[0078] Figure 24 is a schematic diagram of a device according to embodiment A2 of the present invention;

[0079] Figure 25 is a schematic diagram of a device according to embodiment A3 of the present invention;

[0080] Figure 26 This is a schematic diagram of a device in which two lining yarn carriers are respectively provided on two corner wheels of the second and third layers according to embodiment A5 of the present invention;

[0081] Figure 27 is a schematic diagram of a device according to embodiment A6 of the present invention;

[0082] Figure 28 Schematic diagram of a device according to embodiment A5 of the present invention, in which four lining yarn carriers are provided on the corner wheels of the first layer and one lining yarn carrier is provided on each of the corner wheels of the second and third layers;

[0083] Among them, 1-yarn, 2-weaving knot, 3-inner loop, 4-middle loop, 5-outer loop. DETAILED DESCRIPTION

[0084] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0085] Example A1

[0086] A preparation device for a three-dimensional braided preform comprises a chassis, an angle wheel, a dial and a braiding yarn carrier;

[0087] The braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod;

[0088] Each braiding yarn carrier has a matching braiding yarn spindle (such as Figure 16 as shown) and the braiding yarn withdrawal auxiliary frame (as shown Figure 17 As shown), the ceramic eyes on the braiding yarn unwinding auxiliary frame are made of aluminum oxide or titanium oxide;

[0089] There are multiple corner wheels, dials, and braided yarn carrier bases. Each corner wheel has a matching corner wheel drive motor, and each dial has a matching dial drive motor.

[0090] The corner wheel is a circular plate with six cuts;

[0091] The six-notch circular plate is formed as follows: six regions a of identical shape and size are selected on the circular plate u, which are evenly distributed around the central circumference of the circular plate u and do not overlap with each other. The regions a are surrounded by two arcs, one of which coincides with the edge of the circular plate u. The six regions a are removed to form six notches, resulting in a six-notch circular plate.

[0092] Each cutout of the six-cut circular plate is filled with a braided yarn carrier base;

[0093] The dial is a circular plate with two cutouts;

[0094] The process of forming a two-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other, and are evenly distributed around the central circumference of the circular plate u. The regions b are surrounded by two arcs, one of which coincides with the edge of the circular plate v. After removing the two regions b to form two cuts, a six-cut circular plate is obtained.

[0095] The shape and size of area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0096] All six-slit circular plates are distributed in n layers, where n ≥ 2. Each layer is numbered starting from 1 from the inside out. The number of six-slit circular plates in the first layer is 1, and the number of six-slit circular plates in the i-th layer is 6 × (i-1), where 2 ≤ i ≤ n. Any two adjacent six-slit circular plates are arranged with a spacing of 1. The six-slit circular plates in the i-th layer are evenly distributed, and the lines connecting their centers form a regular hexagon. The vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the six lines radiating outward from the center point of the six-slit circular plate in the first layer.

[0097] Each cutout of the six-cut circular plate is filled with a braided yarn carrier base; any two adjacent six-cut circular plates have one cutout facing each other, and the braided yarn carrier bases in the two opposite cutouts are simultaneously filled with two cutouts of a two-cut circular plate;

[0098] A metal bunching ring, a pair of rollers and a winding wheel are arranged above the braiding yarn carrier. The metal bunching ring is located below the pair of rollers and is grounded, and the winding wheel is located above the pair of rollers.

[0099] Example A2

[0100] A preparation device for a three-dimensional braided preform is basically the same as Example A1, except that: at least one corner wheel is provided with a lining yarn carrier located at the center of the corner wheel; the lining yarn carrier includes a lining yarn carrier base and a lining yarn carrier straight rod, each lining yarn carrier has a matching lining yarn spindle and a lining yarn withdrawal auxiliary frame, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of aluminum oxide or titanium oxide.

[0101] Example A3

[0102] A device for preparing a three-dimensional braided preform is basically the same as that in embodiment A1, except that: at least one corner wheel is provided with a lining yarn carrier greater than one located at the center of the corner wheel;

[0103] like Figure 13 As shown, the lining yarn carrier includes a lining yarn carrier base and a lining yarn carrier straight rod. The lining yarn carrier base is circular in shape, and balls are embedded in the circumference and bottom surfaces.

[0104] Each lining yarn carrier has a matching lining yarn spindle and lining yarn unwinding auxiliary frame. The porcelain eye on the lining yarn unwinding auxiliary frame is made of aluminum oxide or titanium oxide.

[0105] like Figure 11 As shown, the angle wheel with the lining yarn carrier is provided with a circular slide rail and a circular through hole, and the circular through hole is located directly above the circular slide rail;

[0106] The center of the circular slide rail is located on the central axis of the angle wheel, and the lining yarn carrier base is slidably connected to the circular slide rail;

[0107] The circular through hole is used for the lining yarn carrier straight rod to pass through. The diameter of the circular through hole is smaller than the width of the circular slide rail. The cross section of the lining yarn carrier base and the circular slide rail is shown as follows: Figure 12 shown.

[0108] Example A4

[0109] A device for preparing a three-dimensional braided preform is basically the same as that in Example A1, except that:

[0110] When n>2, for each cutout in the six-cutout circular plate of the nth layer that is not opposite to other cutouts, the braiding yarn carrier base in each cutout is filled with one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled with another braiding yarn carrier base;

[0111] When n=2, in each six-notch circular plate of the nth layer, the number of notches that are not opposite to other notches is 3, which are respectively recorded as notch a, notch b and notch c, and notch b is located between notch a and notch c;

[0112] The braiding yarn carrier base in the incision a is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base;

[0113] The braiding yarn carrier base in the incision b is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base;

[0114] The braiding yarn carrier base in the incision c is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with the other braiding yarn carrier base.

[0115] Example A5

[0116] A device for preparing a three-dimensional braided preform is basically the same as that in Example A3, except that: n>2;

[0117] For the cuts in each six-cut circular plate of the nth layer that are not opposite to other cuts, the braiding yarn carrier base in each cut is filled with one cut of a two-cut circular plate, and the other cut of the two-cut circular plate is filled with another braiding yarn carrier base.

[0118] Example A6

[0119] A device for preparing a three-dimensional braided preform is basically the same as that in Example A3, except that: n=2;

[0120] In each six-notch circular plate of the nth layer, the number of notches that are not opposite to other notches is 3, which are respectively recorded as notch a, notch b and notch c, and notch b is located between notch a and notch c;

[0121] The braiding yarn carrier base in the incision a is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base, and the two-incision circular plate is marked as dial a;

[0122] The braiding yarn carrier base in the incision b is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base. The braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-incision circular plate is recorded as dial b;

[0123] The braiding yarn carrier base in the incision c is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base. The two-incision circular plate is marked as dial c.

[0124] Example A7

[0125] A device for preparing a three-dimensional braided preform is basically the same as embodiment A6, except that the braided yarn carrier base in the cutout b does not fill one cutout of a two-cutout circular plate.

[0126] Example B1

[0127] A method for preparing a three-dimensional braided preform comprises the following steps:

[0128] (1) Preparation of raw materials and equipment for three-dimensional braided preforms;

[0129] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0130] Device: A device according to Example A1, such as Figure 2As shown, there are 2 layers of angle wheels, 7 angle wheels, 12 dials, 42 braiding yarn carrier bases, and the porcelain eyes on the braiding yarn unwinding auxiliary frame are made of alumina.

[0131] (2) First, unwind the yarn from the standard reel and then wind it onto the braiding yarn spindle. Then, assemble the braiding yarn spindle and the braiding yarn unwinding auxiliary frame concentrically onto the braiding yarn carrier straight rod of the matching braiding yarn carrier. Finally, pass the yarn on the braiding yarn spindle through the porcelain eye on the side of the braiding yarn unwinding auxiliary frame and then bundle it through the metal bundling ring.

[0132] (3) Weaving three-dimensional woven preforms;

[0133] like Figure 3 As shown, after all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a braiding angle of 30°. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0134] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0135] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0136] (c) Repeat steps (a) to (b) several times, and the trajectory of the yarn is as follows: Figure 10 As shown;

[0137] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0138] The final three-dimensional braided preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer is connected to the i-1-th layer through 12×(i-3)+18 evenly distributed braiding nodes, where i is 2. The axial tensile breaking strength of the three-dimensional braided preform is 2.7kN, and the elongation at break is 3.6%.

[0139] Example B2

[0140] A method for preparing a three-dimensional braided preform comprises the following steps:

[0141] (1) Prepare yarn and equipment;

[0142] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0143] Device: A device of Example A2, such as Figure 24As shown, there are 3 layers of angle wheels, 19 angle wheels, 42 dials, 114 braiding yarn carrier bases, and one lining yarn carrier is provided on each angle wheel. The porcelain eye on the braiding yarn withdrawal auxiliary frame is made of alumina, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of alumina.

[0144] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn withdrawal auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn withdrawal auxiliary frame are concentrically assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn withdrawal auxiliary frame and the porcelain eyes on the side of the lining yarn withdrawal auxiliary frame, and then bundled through the metal bundling ring;

[0145] (3) Weaving three-dimensional woven preforms;

[0146] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0147] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0148] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0149] (c) Repeat steps (a) to (b) multiple times;

[0150] The ambient temperature in steps (2) to (3) is 25°C and the relative humidity is 70%.

[0151] The final three-dimensional braided preform has a three-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional braided preform is 16.8kN, and the elongation at break is 3.8%.

[0152] Example B3

[0153] A method for preparing a three-dimensional braided preform comprises the following steps:

[0154] (1) Prepare yarn and equipment;

[0155] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0156] Device: A device of Example A3, such as Figure 25 As shown, there are 3 layers of angle wheels, 19 angle wheels, 42 dials, 114 braiding yarn carrier bases, 4 lining yarn carriers are provided on each angle wheel, the porcelain eyelets on the braiding yarn unwinding auxiliary frame are made of titanium oxide, and the porcelain eyelets on the lining yarn unwinding auxiliary frame are made of titanium oxide;

[0157] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn withdrawal auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn withdrawal auxiliary frame are concentrically assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn withdrawal auxiliary frame and the porcelain eyes on the side of the lining yarn withdrawal auxiliary frame, and then bundled through the metal bundling ring;

[0158] (3) Weaving three-dimensional woven preforms;

[0159] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0160] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0161] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0162] (c) Repeat steps (a) to (b) multiple times;

[0163] The ambient temperature in steps (2) to (3) is 20°C and the relative humidity is 60%.

[0164] The final three-dimensional braided preform has a three-layer structure, with each layer numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional braided preform is 21.8kN, and the elongation at break is 3.3%.

[0165] Example B4

[0166] A method for preparing a three-dimensional braided preform comprises the following steps:

[0167] (1) Prepare yarn and equipment;

[0168] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0169] Device: A device of Example A4, such as Figure 14 As shown, there are 3 layers of angle wheels, 19 angle wheels, 72 dials, 144 braiding yarn carrier bases, and the porcelain eyes on the braiding yarn unwinding auxiliary frame are made of alumina.

[0170] (2) First, the yarn is wound onto the braiding yarn spindle, and then the braiding yarn spindle and the braiding yarn withdrawal auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and finally the yarn on the braiding yarn spindle is passed through the porcelain eye on the side of the braiding yarn withdrawal auxiliary frame and then bundled through the metal bundling ring;

[0171] (3) Weaving three-dimensional woven preforms;

[0172] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0173] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0174] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0175] (c) Repeat steps (a) to (b) multiple times;

[0176] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0177] The final three-dimensional braided preform (its cross section is as follows Figure 7 As shown, its axial surface is Figure 6 ), has a three-layer structure, with each layer numbered from 1 from the inside to the outside, and the i-th layer is connected to the i-1-th layer through 12×(i-3)+18 evenly distributed braiding nodes, 2≤i≤3; the axial tensile breaking strength of the three-dimensional braided preform is 11.6 kN, and the elongation at break is 4.0%.

[0178] Example B5

[0179] A method for preparing a three-dimensional braided preform comprises the following steps:

[0180] (1) Prepare yarn and equipment;

[0181] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0182] Device: A device of Example A5, such as Figure 26 As shown, there are 3 layers of angle wheels, 19 angle wheels, 72 dials, 144 braiding yarn carrier bases, two lining yarn carriers are respectively provided on the two angle wheels of the second layer and the two angle wheels of the third layer, the porcelain eyes on the braiding yarn withdrawal auxiliary frame are made of titanium oxide, and the porcelain eyes on the lining yarn withdrawal auxiliary frame are made of titanium oxide;

[0183] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn withdrawal auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn withdrawal auxiliary frame are concentrically assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn withdrawal auxiliary frame and the porcelain eyes on the side of the lining yarn withdrawal auxiliary frame, and then bundled through the metal bundling ring;

[0184] (3) Weaving three-dimensional woven preforms;

[0185] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0186] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0187] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0188] (c) Repeat steps (a) to (b) multiple times;

[0189] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0190] The final three-dimensional braided preform (its cross section is as follows Figure 8As shown in FIG, 3 , a 3-layer structure is shown. The layers are numbered from 1 from the inside out. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, some of the holes between the braided nodes are filled, with 2≤i≤3. The axial tensile breaking strength of the 3D braided preform is 13.1 kN, and the elongation at break is 3.9%.

[0191] Example B6

[0192] A method for preparing a three-dimensional braided preform comprises the following steps:

[0193] (1) Prepare yarn and equipment;

[0194] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0195] Device: A device according to Example A6, such as Figure 27 As shown, the number of corner wheels is 2, the number of corner wheels is 7, the number of dials is 30, the number of braiding yarn carrier bases is 60, a lining yarn carrier is provided on each corner wheel, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of titanium oxide, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of titanium oxide;

[0196] (2) First, control the knitting yarn spindle and the lining yarn spindle of the knitting yarn carrier b, and wind the yarn on the knitting yarn spindles and the lining yarn spindles of the other knitting yarn carriers. Then, assemble the knitting yarn spindles and the knitting yarn withdrawal auxiliary frame with the yarn wound thereon concentrically to the knitting yarn carrier straight rod of the matching knitting yarn carrier. At the same time, assemble the lining yarn spindle and the lining yarn withdrawal auxiliary frame concentrically to the lining yarn carrier straight rod of the matching lining yarn carrier. Finally, pass the yarn on the knitting yarn spindle and the yarn on the lining yarn spindle through the porcelain eye on the side of the knitting yarn withdrawal auxiliary frame and the porcelain eye on the side of the lining yarn withdrawal auxiliary frame respectively, and then bundle them through the metal bundling ring;

[0197] (3) Weaving three-dimensional woven preforms;

[0198] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0199] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0200] (b) Controlling the dials other than dials b and c to rotate 180° clockwise in the same direction under the drive of the dial drive motor, and controlling the dial c to rotate 180° counterclockwise under the drive of the dial drive motor;

[0201] (c) Repeat steps (a) to (b) multiple times;

[0202] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0203] The final three-dimensional braided preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braiding nodes. Between the i-th layer and the i-1-th layer, all the holes between the braiding nodes are filled, and i is 2. The axial tensile breaking strength of the three-dimensional braided preform is 3.6kN, and the elongation at break is 3.2%.

[0204] Example B7

[0205] A method for preparing a three-dimensional braided preform comprises the following steps:

[0206] (1) Prepare yarn and equipment;

[0207] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 6k;

[0208] Device: A device of Example A7, such as Figure 23 As shown, the number of corner wheels is 2, the number of corner wheels is 7, the number of dials is 24, the number of braiding yarn carrier bases is 54, 3 lining yarn carriers are set on each corner wheel, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of titanium oxide, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of titanium oxide;

[0209] (2) First, control the knitting yarn spindle and the lining yarn spindle of the knitting yarn carrier b, and wind the yarn on the knitting yarn spindles and the lining yarn spindles of the other knitting yarn carriers. Then, assemble the knitting yarn spindles and the knitting yarn withdrawal auxiliary frame with the yarn wound thereon concentrically to the knitting yarn carrier straight rod of the matching knitting yarn carrier. At the same time, assemble the lining yarn spindle and the lining yarn withdrawal auxiliary frame concentrically to the lining yarn carrier straight rod of the matching lining yarn carrier. Finally, pass the yarn on the knitting yarn spindle and the yarn on the lining yarn spindle through the porcelain eye on the side of the knitting yarn withdrawal auxiliary frame and the porcelain eye on the side of the lining yarn withdrawal auxiliary frame respectively, and then bundle them through the metal bundling ring;

[0210] (3) Weaving three-dimensional woven preforms;

[0211] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0212] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0213] (b) controlling the dials except the dial C to rotate 180° clockwise in the same direction under the drive of the dial drive motor, and the dial C to rotate 180° counterclockwise under the drive of the dial drive motor;

[0214] (c) Repeat steps (a) to (b) multiple times;

[0215] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0216] The final three-dimensional braided preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braiding nodes. Between the i-th layer and the i-1-th layer, all the holes between the braiding nodes are filled, and i is 2. The axial tensile breaking strength of the three-dimensional braided preform is 4.7kN, and the elongation at break is 3.3%.

[0217] Example B8

[0218] A method for preparing a three-dimensional braided preform comprises the following steps:

[0219] (1) Prepare yarn and equipment;

[0220] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 12k;

[0221] Device: A device of Example A4, such as Figure 4 As shown, the number of angle wheels is 7, the number of dials is 30, the number of braiding yarn carrier bases is 60, the number of angle wheels is 2, and the porcelain eyes on the braiding yarn unwinding auxiliary frame are made of titanium oxide;

[0222] (2) First, unwind the yarn from the standard reel and then wind it onto the braiding yarn spindle. Then, assemble the braiding yarn spindle and the braiding yarn unwinding auxiliary frame concentrically onto the braiding yarn carrier straight rod of the matching braiding yarn carrier. Finally, pass the yarn on the braiding yarn spindle through the porcelain eye on the side of the braiding yarn unwinding auxiliary frame and then bundle it through the metal bundling ring.

[0223] (3) Weaving three-dimensional woven preforms;

[0224] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0225] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0226] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0227] (c) Repeat steps (a) to (b) multiple times;

[0228] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0229] The final three-dimensional braided preform (such as Figure 5 As shown in FIG, the preform has a two-layer structure, where the layers are numbered from 1 from the inside out, the i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes, and the holes between the i-th layer and the i-1-th layer are unfilled, where i is 2. The axial tensile breaking strength of the three-dimensional braided preform is 3.0 kN, and the elongation at break is 3.4%.

[0230] Example B9

[0231] A method for preparing a three-dimensional braided preform comprises the following steps:

[0232] (1) Prepare yarn and equipment;

[0233] Yarn: Carbon fiber yarn, tensile strength 4900MPa, elongation at break 1.8%, thickness 12k;

[0234] Device: A device of Example A5, such as Figure 28 As shown, the number of angle wheels is 19, the number of dials is 72, the number of braiding yarn carrier bases is 144, the number of angle wheels is 3 layers, 4 lining yarn carriers are set on one angle wheel of the first layer, 1 lining yarn carrier is set on each of the 6 angle wheels of the second layer and the 12 angle wheels of the third layer, the porcelain eye on the braiding yarn unwinding auxiliary frame is made of alumina, and the porcelain eye on the lining yarn unwinding auxiliary frame is made of alumina;

[0235] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn withdrawal auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn withdrawal auxiliary frame are concentrically assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn withdrawal auxiliary frame and the porcelain eyes on the side of the lining yarn withdrawal auxiliary frame, and then bundled through the metal bundling ring;

[0236] (3) Weaving three-dimensional woven preforms;

[0237] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided preform is obtained. The control process is as follows:

[0238] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0239] (b) Control all dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0240] (c) Repeat steps (a) to (b) multiple times;

[0241] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0242] The final three-dimensional braided preform (its cross section is as follows Figure 9 As shown in FIG, the preform has a three-layer structure, where the layers are numbered from 1 from the inside out. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, with 2≤i≤3. The axial tensile breaking strength of the three-dimensional braided preform is 18.1 kN, and the elongation at break is 3.4%.

[0243] Example B10

[0244] A method for preparing a three-dimensional woven preform is basically the same as that of Example B9, except that: the control process of step (3) when weaving the three-dimensional woven preform is as follows: (a) all the corner wheels are controlled to rotate 60° counterclockwise in the same direction under the drive of the corner wheel driving motor; (b) the dial intervals between the corner wheels of the i-th layer are controlled to remain stationary, the dial intervals between the corner wheels of the i-1th layer and the corner wheels of the i-th layer are controlled to remain stationary, and the other dials are controlled to rotate 180° clockwise in the same direction under the drive of the dial driving motor; and (c) steps (a) to (b) are repeated multiple times.

[0245] The final three-dimensional braided preform has a three-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional braided preform is 18.6kN, and the elongation at break is 3.2%.

Claims

1. A preparation device for a three-dimensional braided preform, comprising a chassis, an angle wheel, a dial and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, and the number of the angle wheel, the dial and the braiding yarn carrier base are all multiple, characterized in that: The corner wheel is a six-cut circular plate, and the dial is a two-cut circular plate; The formation process of the six-cut circular plate is as follows: select six regions a on the circular plate u that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions a are surrounded by two arcs, one of which coincides with the edge of the circular plate u, and the six regions a are cut off to form six cuts to obtain the six-cut circular plate; The formation process of the two-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the six-cut circular plate is obtained after the two regions b are cut off to form two cuts; Area a, area b, and the bottom surface of the base of the braiding yarn carrier are the same in shape and size; All six-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of six-cut circular plates in the first layer is 1, and the number of six-cut circular plates in the i-th layer is 6´(i-1), 2≤i≤n, and any two adjacent six-cut circular plates are arranged at a distance; the six-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the six-cut circular plate in the first layer; Each cut of the six-cut circular plate is filled with a braided yarn carrier base; any two adjacent six-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a two-cut circular plate at the same time.

2. The device for preparing a three-dimensional braided preform according to claim 1, characterized in that: At least one corner wheel is provided with a lining yarn carrier.

3. The device for preparing a three-dimensional braided preform according to claim 2, characterized in that: The angle wheel is provided with a lining yarn carrier, the number of the lining yarn carrier is 1, and the lining yarn carrier is located at the center of the angle wheel.

4. The device for preparing a three-dimensional braided preform according to claim 2, characterized in that: The corner wheel is provided with lining yarn carriers, the number of which is greater than 1, and the lining yarn carriers are distributed in a circle around the central axis of the corner wheel.

5. The device for preparing a three-dimensional braided preform according to claim 4, characterized in that: A circular slide rail is also arranged on the corner wheel provided with the lining yarn carrier, the center of the circular slide rail is located on the central axis of the corner wheel, and the lining yarn carrier is slidably connected with the circular slide rail.

6. The device for preparing a three-dimensional braided preform according to claim 1, characterized in that: Each corner wheel has a matching corner wheel driving motor, each dial has a matching dial driving motor, a pair of rollers is arranged above the braiding yarn carrier, and a winding wheel is arranged above the pair of rollers.

7. The device for preparing a three-dimensional braided preform according to claim 6, characterized in that: A metal bunching ring is arranged above the braiding yarn carrier, and the metal bunching ring is located below a pair of rollers and is grounded.

8. A device for preparing a three-dimensional braided preform according to any one of claims 1 to 7, characterized in that: n>2； For the cuts in each six-cut circular plate of the nth layer that are not opposite to other cuts, the weaving yarn carrier base in each cut is filled with one cut of a two-cut circular plate, and the other cut of the two-cut circular plate is filled with another weaving yarn carrier base.

9. A device for preparing a three-dimensional braided preform according to any one of claims 1 to 7, characterized in that: n=2； In each six-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; The braiding yarn carrier base in the cutout a is filled with one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled with another braiding yarn carrier base, and the two-cutout circular plate is marked as dial a; The braiding yarn carrier base in the incision b is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base, and the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-incision circular plate is recorded as dial b; The braiding yarn carrier base in the cut c is filled with one cut of a two-cut circular plate, and the other cut of the two-cut circular plate is filled with another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c.

10. The device for preparing a three-dimensional braided preform according to any one of claims 1 to 7, characterized in that: n=2； In each six-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; The braiding yarn carrier base in the cutout a is filled with one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled with another braiding yarn carrier base, and the two-cutout circular plate is marked as dial a; The base of the braided yarn carrier in the cutout b does not fill one cutout of a two-cutout circular plate; The braiding yarn carrier base in the cut c is filled with one cut of a two-cut circular plate, and the other cut of the two-cut circular plate is filled with another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c.

11. A method for preparing a three-dimensional braided preform, characterized in that: A preparation device for a three-dimensional woven preform as described in claim 8 or 9 is used, and the specific process is: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are alternately controlled to rotate 180° in the same direction at the same time, and the rotation directions of the angle wheels and the dials are controlled to be opposite. After multiple cycles, a three-dimensional woven preform is obtained.

12. A method for preparing a three-dimensional braided preform, characterized in that: A preparation device for a three-dimensional braided preform as described in claim 9 is used, and the specific process is: after controlling all yarn carriers except the braiding yarn carrier b to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, all the dials except the dial b are rotated 180° at the same time, the rotation directions of the dial a and the dial c are controlled to be opposite, and the rotation directions of the other dials and angle wheels except the dials a~c are controlled to be opposite. After multiple cycles, a three-dimensional braided preform is obtained.

13. A method for preparing a three-dimensional braided preform, characterized in that: A preparation device for a three-dimensional woven preform as described in claim 10 is used, and the specific process is: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are rotated 180° at the same time, and the rotation directions of dial a and dial c are opposite, and the rotation directions of other dials and angle wheels except dial a and dial c are opposite. After multiple cycles, a three-dimensional woven preform is obtained.

14. The method for preparing a three-dimensional braided preform according to any one of claims 11 to 13, characterized in that: The yarn is carbon fiber yarn, the ambient temperature is 20-25° C., and the ambient relative humidity is 60-70%. The braided yarn carrier corresponding to the braided yarn carrier base filled with the cutouts of the six-cut circular plates in the 1st to n-1st layers is recorded as braided yarn carrier X, and the other braided yarn carriers are recorded as braided yarn carrier Y. The diameter of the yarn carried by the braided yarn carrier X is greater than the diameter of the yarn carried by the braided yarn carrier Y.

15. A three-dimensional braided preform, characterized in that: The three-dimensional braided preform is prepared by the preparation method of any one of claims 11 to 14, and has an n-layer structure, each layer is numbered from 1 from the inside to the outside, the i-th layer and the i-1-th layer are connected by 12´(i-3)+18 evenly distributed braided nodes, and 2≤i≤n.

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