Preparation method of integrally woven composite core material and integrally woven composite core material

Abstract

The invention discloses a preparation method of an integrally-woven composite core material and the integrally-woven composite core material. First fibers are arranged in through holes of corner wheels in a penetrating mode, second fibers are arranged on yarn storage devices, and the ends of the first fibers and the ends of the second fibers are bundled and then pulled by a traction device; then controlling the corner wheel to rotate by a first angle in the same direction, enabling the yarn storage devices filled in the corner wheel notches of the corner wheel to rotate along with the corner wheel, then controlling the driving plate to rotate by a second angle in the reverse direction, enabling the yarn storage devices filled in the driving plate notches of the driving plate to rotate along with the driving plate, and repeating for multiple times to obtain a fiber integral woven body; and infiltrating resin into the fiber integral woven body, filling pores of the fiber integral woven body with the resin, and obtaining the integral woven composite core material after the resin is heated, cured and molded. The directional design of the overall mechanical property of the overall woven composite core material can be achieved, and the comprehensive mechanical property of the overall woven composite core material can be improved through the macroscopic three-dimensional overall woven structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite core material preparation, and particularly relates to a preparation method of an integrally woven composite core material and an integrally woven composite core material. Background Art

[0002] Currently, the application of high-performance fiber composites in rod structures mainly focuses on hollow rods, which are commonly found in fields such as unmanned aerial vehicle wing frames, drive shafts, conveying pipelines, and structural pipe fittings. However, in the case of a complex load environment, the hollow rod structure is difficult to meet the requirements of large-size cables, large-span core materials, or main load-bearing lightweight components. At this time, the application of solid rods is particularly important, such as composite core materials for tension cables, overhead line composite cores, marine cable reinforcing ribs, push rods, and bridge anchor cables.

[0003] However, at present, most solid core rod composites are prepared by pultrusion processes, processes combining pultrusion and winding, or processes combining pultrusion and braided sleeves. Most of the fibers inside are arranged parallel to the axis. Without additional protection, in addition to the axial direction, the static mechanical properties in other directions are not fully utilized, and the dynamic mechanical properties are poor. In addition, although the solid core rod composites prepared by the process combining pultrusion and winding wrap the axial unidirectional fibers with a winding layer, and the solid core rod composites prepared by the process combining pultrusion and braided sleeves wrap the axial unidirectional fibers with a braided sleeve layer, both of these processes form a "skin-core structure". In this structure, it is difficult for the "skin" layer to effectively restrain the crack propagation in the "core" layer structure, resulting in poor comprehensive mechanical properties, especially the dynamic mechanical properties.

[0004] Patent CN1898085B discloses an aluminum conductor composite core reinforced cable and its preparation method. The ACCC cable has a composite core surrounded by an outer film and at least one layer of aluminum conductor. The composite core includes multiple fibers in one or more matrix materials, and the fibers are from at least one fiber type. The fibers inside the single-rod type composite core material taking patent CN1898085B as an example are all in a unidirectional arrangement structure. Such composite core materials are highly sensitive to stress concentration, especially in the surface layer where they are easily affected by stress concentration, resulting in damage penetration, or are easily separated at the interfaces of different materials inside and spread rapidly over a large range, that is, crack propagation. Transmission wires equipped with such composite core materials must use a customized terminal joint clamping system for construction. Compared with the conventional level, there are differences in construction efficiency, difficulty, and cost. The key of the customized terminal joint clamping system lies in designing a conical inner cavity and a bushing based on the axis of the composite core material, and using the conical inclined surface to decompose all the vertical pressures of the fittings originally along the diameter direction of the composite core material into partial vertical pressures and axial tensions. The fittings are part of the customized terminal joint clamping system, and the axial tension specifically refers to the surface friction force between the fittings and the composite core material. In addition, the bending and flexible rebound performance of such composite core materials are easily restricted by their own diameter structure, which is also a challenge for the bulk storage and supply transportation of products.

[0005] Patent US8250845B2 relates to a composite twisted pair wire formed by impregnating carbon fibers with a thermoplastic resin, and provides a fiber composite twisted pair wire, which is a cable with a 1×n structure. The cable core is formed by impregnating a carbon fiber bundle with a thermosetting resin and then stranding multiple strands of wire. Each strand of wire is formed by covering the outer periphery of the carbon fiber bundle with fibers and then curing and heat-treating by applying a thermosetting resin. Taking the stranded composite core material in Patent US8250845B2 as an example, by stranding several small-diameter single-rod core materials into a large-diameter core material, compared with the single-rod composite core material, it not only has similar characteristics but also significantly improves the bending performance, can achieve bending and winding with a smaller radius, and has more prominent bending and flexible rebound performance. This is mainly attributed to the existence of a fiber winding layer on the surface of the basic unit core rod, secondly, the multi-strand stranding structure decomposes the axial tensile performance of the basic unit core rod in any direction within the space between the axis and the diameter, and thirdly, there is a small amount of relative displacement space between the basic unit core rods after multi-strand stranding. However, such core materials have relatively high requirements for fine control of the forming process. For example, the two-step method requires precise control of the semi-curing and secondary full-curing temperature ranges of the resin, while the one-step method may have extremely high requirements for the coupling degree of process control and equipment operation. The forming quality of each process section of the basic unit core rod before and after stranding directly determines the comprehensive performance of the complete core material. Affected by the stranding structure, there is a certain loss in the utilization rate of the material mechanical properties in the basic unit core rod, the non-uniformity on the surface of the stranded composite core material is extremely high, the risk of triggering stress concentration and failure is increased, and the requirements for the clamping system are also improved accordingly. In addition, the stranded composite core material also has the possibility of "lantern"-type loosening.

[0006] Patent US9633766B2 discloses an energy-saving conductor with a reduced thermal inflection point and a manufacturing method thereof, which relates to an electrical conductor for electrical transmission and distribution. It has a prestress adjustment for the strength member, such that the conductive material of aluminum, aluminum alloy, copper, copper alloy or copper micro-alloy is substantially tension-free or under compressive stress in the conductor, while before the wire is strung, the strength member is under tensile stress, resulting in a lower thermal inflection point in the wire. Taking the aluminum-clad composite core material as an example in Patent US9633766B2, a layer of aluminum is coated on the single-rod composite core material. To a certain extent, this aluminum layer can improve the bending resistance of the single-rod composite core material, physically isolate the single-rod composite core material, provide environmental weather resistance protection, further enhance the power transmission capacity of the power transmission wire, and at the same time be compatible with the construction requirements of the original metal core clamping system. However, the contact effect between the aluminum layer and the single-rod composite core material is crucial for the forming quality of the aluminum-clad composite core material. If the gap between the aluminum layer and the single-rod composite core material is too large, it is easy to cause the position offset between the aluminum layer and the single-rod composite core material and uneven stress; if the gap between the aluminum layer and the single-rod composite core material is too small, it is easy to cause the aluminum layer to extrude and abrade the single-rod composite core material; in addition, the burrs on the inner surface of the aluminum layer may damage the surface of the single-rod composite core material; and there is a certain risk of achieving absolute closure between the aluminum layer and the single-rod composite core material, and there may be a situation where the residual liquid or gas medium erodes the single-rod composite core material; moreover, the high temperature during the aluminum layer coating is likely to ablate the resin on the single-rod composite core material, exposing the fibers. Since the density orders of magnitude of the fibers and the resin are similar, ablation defects are difficult to detect by means such as vision, ultrasound, and ray without dissection, and the ablation defects remaining inside the aluminum layer will become a major hidden danger inducing product service failure. Summary of the Invention

[0007] In view of the defects of the above-mentioned prior art, the present invention provides a preparation method of an integrally braided composite core material and an integrally braided composite core material, which can realize the directional design of the overall mechanical properties of the integrally braided composite core material and can improve the comprehensive mechanical properties of the integrally braided composite core material by using the macroscopic three-dimensional integral braiding structure.

[0008] The technical solution adopted by the present invention to solve its technical problems is:

[0009] A method for preparing an integral braided composite core material, which is prepared by using a preparation system for the integral braided composite core material, the preparation system comprising an integral braiding device, a traction device and a resin infiltration molding device, the integral braiding device comprising a base and a plurality of angle wheels, a dial and a yarn storage device, six angle wheel cutouts are evenly distributed on the edge of the angle wheel and an angle wheel perforation is provided in the middle, two dial cutouts are symmetrically distributed on the edge of the dial, n circles of angle wheels are distributed on the base from the inside to the outside, the first circle of the angle wheel is one, the i-th circle of the angle wheels is 6×(i-1), 2≤i≤n, the multiple angle wheels in the i-th circle are evenly distributed and the center connection line is a regular hexagon, each angle wheel cutout of each angle wheel is filled with a yarn storage device, each angle wheel cutout of each angle wheel is arranged relative to the corresponding angle wheel cutout of the corresponding adjacent angle wheel, and the yarn storage devices in the two oppositely arranged angle wheel cutouts are respectively filled with two dial cutouts of a dial at the same time;

[0010] The preparation method comprises the following steps:

[0011] S1, firstly insert the first fiber into the perforation of each angle wheel respectively, and arrange the second fiber on each yarn storage device respectively, and bundle the ends of each first fiber and each second fiber and then pull them by a pulling device, then control the angle wheels to rotate in the same direction by a first angle, and the yarn storage devices filled in the cutouts of each angle wheel rotate together with the corresponding angle wheels, then control the dials to rotate in the opposite direction by a second angle, and the yarn storage devices filled in the cutouts of each dial rotate together with the corresponding dials, and after multiple cycles, obtain an integral fiber braided body;

[0012] S2. The fiber integral braided body is impregnated with resin by the resin impregnation molding device so that the resin fills the pores of the fiber integral braided body, and the integral braided composite core material is obtained after the resin is cured and shaped by heat.

[0013] Further,

[0014] In step S1: the first fibers passed through the holes of the corner wheels are respectively wound on corresponding winding reels, and each winding reel is arranged on a pay-off frame, the first fibers are carbon fibers, and the second fibers are unidirectionally twisted liquid crystal polymer fibers, and the twist degree is 5-30 twists / m;

[0015] In step S2: the resin is a liquid crystal polymer resin.

[0016] Furthermore, in step S1: in each weaving cycle action, firstly, the angle wheels are synchronously controlled to rotate in the same direction by a first angle, and then the dials are synchronously controlled to rotate in the opposite direction by a second angle.

[0017] Further, three circles of corner wheels are distributed on the base from the inside to the outside, and five circles of dials are distributed from the inside to the outside. Among them, both the first circle of dial layer and the second circle of dial layer include six dials, the third circle of dial layer includes eighteen dials, the fourth circle of dial layer includes twelve dials, and the fifth circle of dial layer includes thirty dials; in step S1: in each knitting cycle action, first synchronously control each of the corner wheels to rotate in the same direction by a first angle, and then synchronously control some of the dials in the first circle of dial layer and the third circle of dial layer to rotate in the opposite direction by a second angle, and at the same time and synchronously control all of the dials in the second circle of dial layer, the fourth circle of dial layer and the fifth circle of dial layer to rotate in the opposite direction by the second angle.

[0018] Further, in step S1: in each knitting cycle action, the first angle is 60°, and the second angle is 180°.

[0019] Further, in step S1: in each knitting cycle action, three non-adjacent dials in the first circle of dial layer are controlled to rotate, and nine non-adjacent dials in the third circle of dial layer are controlled to rotate.

[0020] Further, in step S1: the carbon fiber has a thickness of 12 - 48K and a tensile strength greater than or equal to 5300 MPa, and the liquid crystal polymer fiber has a thickness of 750D - 2500D and a tensile strength greater than or equal to 100ρ MPa, where ρ represents the density of the liquid crystal polymer fiber.

[0021] Further, the resin infiltration molding device includes a preforming area, a resin injection infiltration area, and a heating and curing area. The preforming area is connected with an exhaust component for exhausting air from the fiber overall braid and forming a negative pressure, and the resin injection infiltration area is connected with a resin injection component for injecting resin into the fiber overall braid with a negative pressure formed;

[0022] Step S2 is specifically as follows: the fiber overall braid enters the preforming area under the traction of the traction device, the exhaust component exhausts air from the fiber overall braid and forms a negative pressure, the fiber overall braid with a negative pressure formed enters the resin injection infiltration area under the traction of the traction device, the resin injection component injects resin into the resin injection infiltration area, and the hot-melt resin quickly penetrates into the fiber overall braid and fills the pores under the combined action of the positive pressure of the resin injection component and the negative pressure of the fiber overall braid, obtaining a resin fiber overall braid mixture. The resin fiber overall braid mixture enters the heating and curing area under the traction of the traction device and is cured by heat, and under the shaping action of the inner cavity of the cylindrical mold at the heating and curing area, a rod-shaped overall braided composite core material is obtained.

[0023] Further, each of the corner wheel notches is composed of two arcs, and one of the arcs coincides with the edge of the corresponding corner wheel. Each of the dial notches is composed of two arcs, and one of the arcs coincides with the edge of the corresponding dial. The corner wheel is driven to rotate by a supporting corner wheel drive motor, and the dial is driven to rotate by a supporting dial drive motor.

[0024] An integrally woven composite core material is prepared by using the preparation method of the integrally woven composite core material described above.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The preparation method of the integral braided composite core material in the present invention includes the following steps: S1. First, pass the first fibers through the perforations of each corner wheel respectively, and arrange the second fibers on each yarn storage device respectively. Bundle the ends of each first fiber and each second fiber and then pull them by a traction device. Then, control the corner wheels to rotate in the same direction by a first angle. The yarn storage devices filled at the cutouts of each corner wheel rotate along with the corresponding corner wheels. Then, control the dial to rotate in the opposite direction by a second angle. The yarn storage devices filled at the cutouts of each dial rotate along with the corresponding dial. After repeating the cycle many times, a fiber integral braid is obtained; S2. Infiltrate the fiber integral braid with resin through a resin infiltration and molding device, so that the resin fills the pores of the fiber integral braid. After the resin is heated and cured and shaped, an integral braided composite core material is obtained. In the present invention, by controlling the rotation direction and rotation angle of the corner wheels, the rotation direction and rotation angle of the yarn storage devices filled at the cutouts of each corner wheel are controlled, and by controlling the rotation direction and rotation angle of the dial, the rotation direction and rotation angle of the yarn storage devices filled at the cutouts of each dial are controlled, thereby controlling the rotation direction and rotation angle of the second fibers arranged on the corresponding yarn storage devices. In this way, the distribution density of the braiding nodes in the fiber integral braid can be freely adjusted. Specifically, by relatively increasing the density of the braiding nodes in the near-surface layer range of the fiber integral braid, the clamping reliability and the holding force of the integral braided composite core material are improved, and the comprehensive mechanical properties such as compression resistance, bending resistance, and impact resistance are improved. By relatively reducing the density of the braiding nodes in the near-axis range of the fiber integral braid, the axial straightening rate of the internal second fibers is increased, and the axial tensile resistance performance of the internal second fibers is retained as much as possible. Therefore, the present invention can achieve the directional design of the overall mechanical properties of the integral braided composite core material and can use the macroscopic three-dimensional integral braiding structure to improve the comprehensive mechanical properties of the integral braided composite core material; and because each first fiber is respectively passed through the corresponding perforation of the corner wheel, the first fiber will not rotate along with the corner wheel during the rotation of the corner wheel, so each first fiber does not participate in the braiding. Therefore, each first fiber in the prepared integral braided composite core material is distributed along the axis, which can enhance the axial tensile resistance performance of the integral braided composite core material; in addition, because the resin can fill the pores of the fiber integral braid, it can fully bond and support each first fiber and each second fiber, so that each first fiber and each second fiber can cooperate to fully bear the load.

[0027] In the present invention, since the first fiber is a carbon fiber and the second fiber is a unidirectionally twisted liquid crystal polymer fiber; in this way, the comprehensive properties of the carbon fiber and the liquid crystal polymer fiber can be organically integrated and fully exerted, and the comprehensive mechanical properties of the basic reinforcing phase in the integral braided composite core material can be improved by using the advantages of the microscopic twisted structure of the liquid crystal polymer fiber, and it works synergistically with the macroscopic three-dimensional integral braiding structure.

[0028] The macroscopic three-dimensional integral braided structure of this integral braided composite core material does not involve the "skin-core structure" problem. The structure is integrated from the inside out, which can effectively inhibit the axial diffusion trend of cracks along the separation and extension direction of the fiber-resin interface, and can also effectively inhibit the radial diffusion trend of cracks along the fracture direction of the fiber-resin interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a top view structural schematic diagram of the integral braiding device in the present invention;

[0030] Figure 2 is Figure 1 an enlarged structural schematic diagram of one of the corner wheels in;

[0031] Figure 3 is Figure 1 an enlarged structural schematic diagram of one of the dials in;

[0032] Figure 4 is Figure 1 a schematic diagram of each ring of the dial layers in.

[0033] Explanation of the reference numerals in the drawings: 1. Corner wheel, 101. Corner wheel perforation, 102. Corner wheel notch, 2. Dial, 201. Dial notch, 301. First ring of dial layers, 302. Second ring of dial layers, 303. Third ring of dial layers, 304. Fourth ring of dial layers, 305. Fifth ring of dial layers. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following further describes in detail the specific embodiments of the present invention with reference to the drawings. These embodiments are only used to illustrate the present invention and are not intended to limit the present invention.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0038] A preparation method of an integrally woven composite core material is carried out by using a preparation system for the integrally woven composite core material. The preparation system includes an integral weaving device, a traction device, and a resin infiltration and molding device. As Figure 1 shown, the integral weaving device includes a base and a plurality of corner wheels 1, a dial 2, and a yarn storage device, all of which are in plural numbers. Six corner wheel notches 102 are evenly distributed in a circle on the edge of the corner wheel 1, and a corner wheel perforation 101 is provided in the middle. See Figure 2 , two dial notches 201 are symmetrically distributed in a circle on the edge of the dial 2. See Figure 3 , n circles of corner wheels are distributed on the base from the inside to the outside. The number of corner wheels in the first circle is one, and the number of corner wheels in the i-th circle is 6×(i - 1), where 2≤i≤n. The plurality of corner wheels 1 in the i-th circle are evenly distributed and the center connection lines form a regular hexagon. Each corner wheel notch 102 of each corner wheel 1 is filled with a yarn storage device, and each corner wheel notch 102 of each corner wheel 1 is arranged opposite to the corresponding corner wheel notch 102 of the adjacent corner wheel 1. The yarn storage devices in two opposite corner wheel notches 102 are simultaneously filled with the two dial notches 201 of a dial 2 respectively; where Figure 2 the circle A of the corner wheel notch 102 is used to arrange the yarn storage device, and where Figure 3 the circle B of the dial notch 201 is also used to arrange the yarn storage device;

[0039] The preparation method includes the following steps:

[0040] S1. First, a first fiber is respectively passed through each corner wheel perforation 101, and a second fiber is respectively arranged on each yarn storage device. The ends of each first fiber and each second fiber are bundled and then pulled by the traction device. Then, the corner wheels 1 are controlled to rotate in the same direction by a first angle. The yarn storage devices filled at each corner wheel notch 102 rotate along with the corresponding corner wheels 1. Then, the dial 2 is controlled to rotate in the opposite direction by a second angle. The yarn storage devices filled at each dial notch 201 rotate along with the corresponding dial 2. After repeating many times, a fiber integral woven body is obtained;

[0041] S2. The fiber integrated braid is infiltrated with resin by a resin infiltration molding device, so that the resin fills the pores of the fiber integrated braid, and an integrated braided composite core material is obtained after the resin is heated and cured and shaped.

[0042] In the present invention, by controlling the rotation direction and rotation angle of the corner wheel 1, the rotation direction and rotation angle of the yarn storage devices filled at the respective corner wheel notches 102 of the corner wheel 1 are controlled, and by controlling the rotation direction and rotation angle of the dial 2, the rotation direction and rotation angle of the yarn storage devices filled at the respective dial notches 201 of the dial 2 are controlled, thereby controlling the rotation direction and rotation angle of the second fibers arranged on the corresponding yarn storage devices. In this way, the distribution density of the braiding knots in the fiber integrated braid can be freely adjusted. Specifically, by relatively increasing the braiding knot density in the near-surface layer range of the fiber integrated braid, the clamping reliability and the holding force of the integrated braided composite core material are improved, and the comprehensive mechanical properties such as compression resistance, bending resistance, and impact resistance are enhanced. By relatively reducing the braiding knot density in the near-axis range of the fiber integrated braid, the axial straightening rate of the internal second fibers is increased, and the axial tensile resistance performance of the internal second fibers is retained as much as possible. Therefore, the present invention can achieve the directional design of the overall mechanical properties of the integrated braided composite core material and can improve the comprehensive mechanical properties of the integrated braided composite core material by using the macroscopic three-dimensional integrated braiding structure. Since each first fiber is respectively inserted into the corresponding corner wheel through-hole 101, the first fiber will not rotate along with the corner wheel 1 during the rotation of the corner wheel 1, so each first fiber does not participate in the braiding. Therefore, each first fiber in the obtained integrated braided composite core material is distributed axially without torsion, which can enhance the axial tensile resistance performance of the integrated braided composite core material. In addition, since the resin can fill the pores of the fiber integrated braid, it can fully bond and support each first fiber and each second fiber, so that each first fiber and each second fiber can cooperate to fully bear the load.

[0043] In the present invention, the first fiber in the axial direction passes through the corresponding corner wheel through-hole 101 and fills the braiding hole positions in the fiber integrated braid, so that an ideal untwisted straight distribution of the first fiber for axial lining can be achieved, which can greatly reduce the braiding friction of the first fiber for axial lining by the second fibers at other braiding positions on the corner wheel, reduce the probability of wear of the first fiber for axial lining, and greatly improve the mechanical property performance of the first fiber for axial lining.

[0044] Among them, each corner wheel notch 102 is composed of two arcs, and one of the arcs coincides with the edge of the corresponding corner wheel 1, and each dial notch 201 is composed of two arcs, and one of the arcs coincides with the edge of the corresponding dial 2; the corner wheel 1 is driven to rotate by a supporting corner wheel 1 drive motor, and the dial 2 is driven to rotate by a supporting dial 2 drive motor.

[0045] Among them,

[0046] In step S1: The first fibers passing through the perforations 101 of each corner wheel are respectively wound around corresponding winding disks, and each winding disk is arranged on a wire pay-off rack. The first fiber is a carbon fiber, and the second fiber is a unidirectionally twisted liquid crystal polymer fiber. In this way, the comprehensive properties of the carbon fiber and the liquid crystal polymer fiber can be organically integrated and fully utilized. The microscopic twisted structure advantage of the liquid crystal polymer fiber is used to improve the comprehensive mechanical properties of the basic reinforcing phase in the overall braided composite core material, and it works synergistically with the macroscopic three-dimensional overall braided structure to jointly improve the mechanical properties such as bending, torsion, impact resistance, and fatigue resistance. Among them, the twist of the liquid crystal polymer fiber is 5 - 30 turns / meter, preferably 10 - 25 turns / meter. Among them, the thickness of the carbon fiber is 12 - 48K and the tensile strength is greater than or equal to 5300 MPa, and the thickness of the liquid crystal polymer fiber is 750D - 2500D and the tensile strength is greater than or equal to 100ρ MPa, where ρ represents the density of the liquid crystal polymer fiber.

[0047] In step S2: The resin is a liquid crystal polymer resin.

[0048] Among them,

[0049] The resin infiltration molding device includes a preforming area, a resin injection infiltration area, and a heating and curing area. The preforming area is connected with an exhaust assembly for exhausting the fiber overall braid and forming a negative pressure, and the resin injection infiltration area is connected with a resin injection assembly for injecting resin into the fiber overall braid with a negative pressure formed.

[0050] Step S2 is specifically as follows: The fiber overall braid enters the preforming area under the traction of the traction device, the exhaust assembly exhausts the fiber overall braid and forms a negative pressure. The fiber overall braid with a negative pressure enters the resin injection infiltration area under the traction of the traction device, and the resin injection assembly injects the resin into the resin injection infiltration area. The hot-melt resin quickly penetrates into the fiber overall braid and fills the pores under the combined action of the positive pressure of the resin injection assembly and the negative pressure of the fiber overall braid, obtaining a resin-fiber overall braid mixture. The resin-fiber overall braid mixture enters the heating and curing area under the traction of the traction device and is cured by heating. Under the shaping effect of the inner cavity of the cylindrical mold in the heating and curing area, a rod-shaped overall braided composite core material is obtained. In this way, the purpose of quickly, efficiently, and low-foam infiltrating the fiber overall braid with resin can be achieved through the positive and negative pressure infiltration technology.

[0051] Among them, before the braiding process, there is also a step of treating the fibers with atmospheric plasma in sequence according to the braiding process. The surface of the first fiber and the second fiber is activated by plasma glow to improve the interfacial bonding performance between the fiber overall braid and the resin, and the atmospheric plasma treatment technology is combined with the positive and negative pressure infiltration technology to synergistically improve the infiltration and penetration efficiency of the resin and the fiber overall braid. In one of the embodiments,

[0052] In step S1: In each knitting cycle action, first synchronously control the same-direction rotation of each corner wheel 1 by a first angle, and then synchronously control the reverse rotation of each dial 2 by a second angle. Preferably, the first angle is 60°, and the second angle is 180°.

[0053] In another embodiment,

[0054] There are three circles of corner wheels distributed from the inside to the outside on the base and five circles of dials distributed from the inside to the outside. See Figure 4 , where there are a total of nineteen corner wheels. Among them, both the first dial layer 301 and the second dial layer 302 include six dials 2, the third dial layer 303 includes eighteen dials 2, the fourth dial layer 304 includes twelve dials 2, and the fifth dial layer 305 includes thirty dials 2; In step S1: In each knitting cycle action, first synchronously control the same-direction rotation of each corner wheel 1 by a first angle, and then synchronously control the reverse rotation of some dials 2 in the first dial layer 301 and the third dial layer 303 by a second angle, and at the same time and synchronously control the reverse rotation of all dials 2 in the second dial layer 302, the fourth dial layer 304, and the fifth dial layer 305 by a second angle. Preferably, the first angle is 60°, and the second angle is 180°.

[0055] Among them, in step S1: In each knitting cycle action, control the rotation of three non-adjacent dials 2 in the first dial layer 301 and control the rotation of nine non-adjacent dials 2 in the third dial layer 303. Specifically, control the rotation of the dials 2 with a diagonal background in the first dial layer 301 and control the rotation of the dials 2 with a grid background in the third dial layer 303. Since some dials 2 in the first dial layer 301 and the third dial layer 303 participate in knitting and some dials 2 do not participate in knitting, while reducing knitting nodes and increasing the axial straightening distribution rate of the knitting yarn, that is, the liquid crystal polymer fiber, the overall coherence of the internal and external knitting structures can be taken into account. Among them, in step S1: The carbon fiber has a thickness of 12K and a tensile strength of 5500 MPa. Twelve bundles of 12K carbon fibers are filled in the corner wheel perforation 101 at the center position of the base, and six bundles of 12K carbon fibers are filled in each corner wheel perforation 101 at the remaining positions of the base. Then, a total of 120 bundles of 12K carbon fibers are filled on the base. The liquid crystal polymer fiber has a thickness of 1000D and a tensile strength of 3600 MPa. Two bundles of 1000D liquid crystal polymer fibers are arranged on each yarn storage device, and the twist of each bundle of liquid crystal polymer fibers is 20 twists / meter.

[0056] Among them, in step S2: The tensile strength of the cured liquid crystal polymer resin reaches 125 MPa.

[0057] In this way, the purpose of smaller braiding node density in the near-axis range of the overall fiber braided body and larger braiding node density near the surface can be achieved. The tensile strength of the obtained overall braided composite core material is 3100MPa, the bending strength is 1170MPa, and the bending radius can be no less than 38 times the diameter of the overall braided composite core material. It can rebound and reset normally without damage, and the bending fatigue life can reach at least 300,000 times. After low-speed impact, the tensile properties of the overall braided composite core material can continue to be maintained at more than 75% of the normal level, and can be combined with a composite material lining kit and directly fixed using a conventional metal core clamping system. The overall braided composite core material can still maintain normal load service under 25% damage tolerance conditions until inspection and maintenance are triggered to eliminate hidden dangers.

[0058] An integral braided composite core material is prepared by the above-mentioned method for preparing the integral braided composite core material. The integral braided composite core material can be applied to tension cores in power transmission conductors, tension cables for building facilities, main load-bearing parts for anchor cables of deep-sea platforms, and the like.

[0059] In the present invention, the more the second fibers in the integral woven composite core material are distributed along a certain direction, the better the static performance of the integral woven composite core material in this direction, the stronger the ability of the integral woven composite core material to suppress crack propagation, and the better the dynamic performance. The macroscopic physical structure of the integral woven composite core material mainly affects the bending and flexible resilience of the integral woven composite core material.

[0060] In the present invention, the macroscopic three-dimensional integral braided structure of the integral braided composite core material is an integral structure formed by densely stacking and overlapping interlocking nodes of the first fiber and the second fiber within a spatial range, which has the characteristics of being one-piece and not layered. The braided nodes in the integral braided body of the fiber can form an effective physical barrier to the spread of cracks, and the dynamic properties of the integral braided composite core material are strengthened, so that the comprehensive mechanical properties of the integral braided composite core material can be effectively exerted. Therefore, the integral braided composite core material can solve the many performance disadvantages of the existing composite core materials in the above-mentioned background technology by applying the macroscopic three-dimensional integral braided structure. The integral braided composite core material can fully exert the axial mechanical properties without the need for additional protective measures, and has good flexible rebound and retractable characteristics. It also has excellent comprehensive mechanical properties such as anti-torsion, anti-bending, anti-compression and anti-impact, and the molding process is relatively simple and efficient.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A preparation method of an integrally woven composite core material is prepared by using a preparation system for an integrally woven composite core material. The preparation system includes an integral weaving device. The integral weaving device includes a base and a plurality of corner wheels (1), a dial (2), and yarn storage devices, all of which are in a plurality. Six corner wheel notches (102) are evenly distributed in a circle on the edge of the corner wheel (1). Two dial notches (201) are symmetrically distributed in a circle on the edge of the dial (2). n circles of corner wheels are distributed on the base from the inside to the outside. There is one corner wheel in the first circle, and there are 6×(i - 1) corner wheels in the i-th circle, where 2 ≤ i ≤ n. The plurality of corner wheels (1) in the i-th circle are evenly distributed and the center connection lines form a regular hexagon. Each corner wheel notch (102) of each corner wheel (1) is filled with a yarn storage device. Each corner wheel notch (102) of each corner wheel (1) is arranged opposite to the corresponding corner wheel notch (102) of the adjacent corner wheel (1). The yarn storage devices in two oppositely arranged corner wheel notches (102) simultaneously fill the two dial notches (201) of a dial (2) respectively. It is characterized in that: A corner wheel through hole (101) is provided in the middle of each corner wheel (1); The preparation method comprises the following steps: S1, firstly insert the first fiber into each of the perforations (101) of the angle wheel, and arrange the second fiber on each of the yarn storage devices, and then bundle the ends of the first fiber and the second fiber and pull them through a pulling device, then control the angle wheel (1) to rotate in the same direction by a first angle, and the yarn storage device filled in each of the angle wheel cutouts (102) rotates together with the corresponding angle wheel (1), then control the dial (2) to rotate in the opposite direction by a second angle, and the yarn storage device filled in each of the dial cutouts (201) rotates together with the corresponding dial (2), and after multiple cycles, a fiber integral braided body is obtained; S2. The fiber integral braid is impregnated with resin so that the resin fills the pores of the fiber integral braid, and the integral braided composite core material is obtained after the resin is cured and shaped by heat.

2. The method for preparing an integrally braided composite core material according to claim 1, characterized in that: In step S1: the first fibers passed through the through holes (101) of the angle wheels are respectively wound on corresponding winding reels, and each winding reel is arranged on a pay-off frame, the first fibers are carbon fibers, and the second fibers are unidirectionally twisted liquid crystal polymer fibers, and the twist degree is 5-30 twists / m; In step S2: the resin is a liquid crystal polymer resin.

3. The preparation method of an integrally woven composite core material according to claim 2, characterized in that, In step S1: in each weaving cycle action, firstly, the angle wheels (1) are synchronously controlled to rotate in the same direction by a first angle, and then the dials (2) are synchronously controlled to rotate in the opposite direction by a second angle.

4. The preparation method of an integrally woven composite core material according to claim 2, characterized in that: The base is provided with three circles of angle wheels from the inside to the outside and five circles of dials from the inside to the outside, wherein the first circle of dials (301) and the second circle of dials (302) each include six dials (2), the third circle of dials (303) includes eighteen dials (2), the fourth circle of dials (304) includes twelve dials (2), and the fifth circle of dials (305) includes thirty dials (2); in step S1: in each weaving cycle action, firstly, synchronously controlling each of the angle wheels (1) to rotate in the same direction by a first angle, then synchronously controlling some of the dials (2) in the first circle of dials (301) and the third circle of dials (303) to rotate in the opposite direction by a second angle, and simultaneously and synchronously controlling all of the dials (2) in the second circle of dials (302), the fourth circle of dials (304) and the fifth circle of dials (305) to rotate in the opposite direction by a second angle.

5. The preparation method of an integrally woven composite core material according to claim 3 or 4, characterized in that In step S1: in each weaving cycle action, the first angle is 60° and the second angle is 180°.

6. The preparation method of an integrally woven composite core material according to claim 4, characterized in that, In step S1: in each knitting cycle action, three non-adjacent dials (2) in the first dial layer (301) are controlled to rotate, and nine non-adjacent dials (2) in the third dial layer (303) are controlled to rotate.

7. The preparation method of an integrally woven composite core material according to claim 2, characterized in that, In step S1: the carbon fiber has a thickness of 12 - 48K and a tensile strength of not less than 5300 MPa; the liquid crystal polymer fiber has a thickness of 750D - 2500D and a tensile strength of not less than 100ρ MPa, where ρ represents the density of the liquid crystal polymer fiber.

8. The preparation method of an integrally woven composite core material according to claim 1, characterized in that, The preparation system further includes a resin infiltration and molding device, which includes a preforming area, a resin injection and infiltration area, and a heating and curing area. The preforming area is connected with an exhaust assembly for exhausting air from the overall fiber braid and forming a negative pressure. The resin injection and infiltration area is connected with a resin injection assembly for injecting resin into the overall fiber braid with a negative pressure. Step S2 is specifically as follows: the overall fiber braid enters the preforming area under the traction of the traction device. The exhaust assembly exhausts air from the overall fiber braid and forms a negative pressure. The overall fiber braid with a negative pressure enters the resin injection and infiltration area under the traction of the traction device. The resin injection assembly injects resin into the resin injection and infiltration area. The hot melt resin quickly penetrates into the overall fiber braid and fills the pores under the combined action of the positive pressure of the resin injection assembly and the negative pressure of the overall fiber braid, obtaining a resin-fiber overall braid mixture. The resin-fiber overall braid mixture enters the heating and curing area under the traction of the traction device and is cured by heating. Under the shaping effect of the inner cavity of the cylindrical mold in the heating and curing area, a rod-shaped overall braided composite core material is obtained.

9. The preparation method of an integrally woven composite core material according to claim 1, wherein: Each of the corner wheel cutouts (102) is composed of two arcs, and one of the arcs coincides with the edge of the corresponding corner wheel (1). Each of the dial cutouts (201) is composed of two arcs, and one of the arcs coincides with the edge of the corresponding dial (2). The corner wheel (1) is driven to rotate by a supporting corner wheel (1) drive motor. The dial (2) is driven to rotate by a supporting dial (2) drive motor.

10. A monolithic woven composite core material, characterized in that: It is prepared by using the preparation method of the overall braided composite core material according to any one of claims 1 - 4, 6 - 9.

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