Hybrid fiber composite material rib with ribs on surface and preparation method thereof

Abstract

The invention relates to a hybrid fiber composite material rib with ribs on the surface and a preparation method thereof, and belongs to a resin fiber material. The rib material comprises carbon fibers, other fibers and a resin matrix, the carbon fibers and the other fibers are embedded in the resin matrix, and spiral resin ribs are arranged on the surface of the rib material. The other fibers are selected from one or more of aramid fibers, basalt fibers and glass fibers. The carbon fibers are distributed at the core part of the rib material, and the other fibers are distributed at the periphery of the carbon fibers. The diameter of the rib material is 2mm-36mm, the volume content of the carbon fibers is 52%-57%, and the volume content of the other fibers is 19%-22%. The rib material has the excellent axial strength and elasticity modulus of the core layer carbon fiber and the additional performance of other fibers on the surface layer, the comprehensive performance and integrity of the rib material are improved, and the service requirements of more complex application scenes are met.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, and mainly relates to a hybrid fiber composite material with resin ribs on the surface and its preparation method. Background Technology

[0002] Fiber-reinforced composite materials are made by mixing reinforcing fibers and a resin matrix using physical or chemical methods. They are lightweight, high-strength, and corrosion-resistant, and are widely used in aerospace, transportation, wind power generation, and civil engineering. Currently, single-fiber composite materials each possess their own prominent performance characteristics. For example, carbon fiber composites exhibit high strength and modulus, and fatigue resistance; aramid fiber composites possess high toughness and impact resistance; glass fiber has good insulation and weather resistance; and basalt fiber has ultra-wide temperature range stability. Carbon fiber composite reinforcement for structural engineering possesses excellent properties such as lightweight, high strength, corrosion resistance, fatigue resistance, and a low coefficient of linear expansion. It is an ideal material to replace traditional steel wire in ultra-long-span bridge engineering and complex environmental structural engineering, fundamentally solving problems such as steel wire fatigue, corrosion, and high self-weight. For example, the Changtai Yangtze River Bridge, a major national strategic project scheduled to open in 2025 and the world's largest span cable-stayed bridge, uses carbon fiber composite reinforcement to solve problems such as low main beam constraint efficiency, beam end displacement, and large internal forces in the main tower. However, carbon fiber composite reinforcement is a brittle material, and its relatively low transverse properties (such as torsional strength, shear strength, and impact resistance) are key factors restricting its construction and large-scale application. Therefore, using carbon fiber as the core material and aramid fiber, glass fiber, basalt fiber, or other fiber materials as the surface material, and employing an interlayer hybridization method to prepare the reinforcement, results in surface-ribbed hybrid fiber composite reinforcement that combines the outstanding properties of two or more fibers. For example, using an interlayer hybridization method with aramid fiber and carbon fiber to prepare aramid fiber-carbon fiber hybrid composite reinforcement that simultaneously achieves high toughness, high corrosion resistance, high fatigue resistance, and high mechanical properties, thus solving the problem of weak transverse properties in carbon fiber composite reinforcement. Furthermore, traditional pultrusion processes suffer from low production efficiency, affecting the timely delivery of major projects. Currently, some surface-ribbed hybrid fiber composite reinforcements have been developed domestically.

[0003] For example, Chinese invention patent CN119686492A discloses an embedded hybrid fiber threaded rebar and its manufacturing method. This method first pre-forms resin-impregnated fiber bundles into circular rods using a pre-forming mold, then wraps them with a release cloth before curing them into a circular mold to form a circular rod. After removing the release cloth, additional rib fiber bundles are embedded in the indentation grooves and cured in an oven. Essentially, this method involves wrapping fiber bundles around the surface of a smooth circular rebar. This method results in low bond strength between the additional rib fiber bundles and the smooth circular rebar, making them prone to detachment and failing to fully utilize the tensile properties of the carbon fiber composite rebar. Furthermore, the process involves wrapping the pre-formed circular rod with the release cloth before curing in the mold. The uneven surface of the rebar during this process leads to significant friction, easily causing mold blockage. Additionally, the production efficiency is low due to limitations in the length of the curing mold. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings by designing a surface-ribbed hybrid fiber composite reinforcement and its preparation method. The elastic modulus is customized by adjusting the ratio of carbon fiber to other fibers, overcoming the disadvantage of low elastic modulus in traditional single-carbon fiber composite reinforcements. The reinforcement is cured and molded in a single step, resulting in a low probability of mold blockage and high production speed.

[0005] The objective of this invention is achieved as follows: a hybrid fiber composite material rib with surface ribs, characterized in that: the rib material includes carbon fiber, other fibers, and a resin matrix, wherein the carbon fiber and other fibers are embedded inside the resin matrix, and the surface of the rib material has spiral resin ribs.

[0006] Preferably, the other fibers are selected from one or more of aramid fibers, basalt fibers, and glass fibers.

[0007] Preferably, the carbon fibers are distributed in the core of the reinforcing material, and other fibers are distributed on the outer periphery of the carbon fibers.

[0008] Preferably, the diameter of the reinforcing bar is 2mm-36mm, the volume content of carbon fiber is 52%-57%, and the volume content of other fibers is 19%-22%.

[0009] Preferably, the thickness of the resin rib is 1%-6% of the diameter of the reinforcing bar, the width of the resin rib is in the range of 4mm-15mm, and the pitch of the resin rib is 2mm-10mm.

[0010] Preferably, the longitudinal elastic modulus of the reinforcing bar is... E C The following calculation model was used for adjustment. The calculation model follows the principle of iso-strain in the micromechanics of unidirectional composite materials. The required number of fibers and fiber volume content were calculated using this calculation model.

[0011] In the formula, T cf The fineness of carbon fiber, or carbon fiber bundle, is measured in g / km. N cf The number of carbon fiber bundles; ρ cf This refers to the density of the carbon fiber bundle, expressed in g / cm³. 3 ; d is the diameter of the reinforcing bar, in mm; T sf This refers to the fineness of other fibers, i.e., other fiber bundles, expressed in g / km. N sf For the number of other fiber bundles; ρ sf The density of other fiber bundles, in g / cm³ 3 ; E cf This represents the longitudinal elastic modulus of the carbon fiber bundle, expressed in GPa. E sf Let q be the longitudinal elastic modulus of the other fiber bundles, in GPa; E c This represents the elastic modulus of the reinforcing bar, expressed in GPa. E m for The elastic modulus of the resin matrix, expressed in GPa.

[0012] The preparation method of the above-mentioned surface-ribbed hybrid fiber composite material reinforcement includes the following steps: Step 1: Draw out several bundles of carbon fiber and other fiber bundles from the yarn frame, and control the tension of each fiber bundle to be uniform. Step 2: The carbon fiber bundles and other fiber bundles are drawn into the resin tank in an orderly manner to impregnate the resin, so that the fiber bundles are fully impregnated with the resin in the impregnation tank. After exiting the resin tank, they enter a circular splitting plate for positioning. The carbon fiber bundles located in the core of the reinforcing material pass through the splitting hole in the center of the splitting plate, while the other fiber bundles located near the surface of the reinforcing material pass through the outer splitting hole on the splitting plate. Step 3: After the fiber bundle passes through the splitting plate, it passes through the bundle-gathering ring and the preforming mold, and the excess resin is extruded to obtain a rib blank with a predetermined cross-section of circular size. The inner diameter of the preforming mold is 2mm-36mm. Step 4: While pulling the reinforcing steel blank forward, wrap nylon tape around the reinforcing steel blank. Use a double-ended wrapping method to continuously, evenly, and symmetrically wrap the nylon tape around the reinforcing steel blank from top to bottom. Keep the wrapping spacing in the range of 4mm-15mm and control the wrapping tension. The nylon tape should only be in contact with the surface of the reinforcing steel blank without tightening it. Keep the carbon fiber bundle orientation on the surface of the reinforcing steel blank straight. The width of the nylon tape is 2mm-10mm and the thickness is 0.2mm-1.5mm. Step 5: The rib blank with nylon strips wrapped around its surface is pulled through several ovens. The temperature of the ovens is set from low to high, from 140℃ to 220℃. In the first stage of oven heating, the resin inside the rib blank expands and its viscosity decreases due to the heat. It begins to overflow from the inside of the rib blank and gradually fills the gaps between the nylon strips. In the second stage of oven heating, the resin undergoes gelation and pre-curing. In the third stage of oven heating, the full curing process is completed. The thickness of the resin ribs is affected by the heating temperature and time in the first stage. The thickness of the resin ribs can be controlled by controlling the oven temperature and length. Step 6: After the surface ribs have been cured, air-cool them and unwind the nylon tape using a double-head unwinding method. The unwinding part of the nylon tape forms a spiral groove, exposing the resin ribs in the gaps between the nylon tapes on the surface of the ribs, forming spiral resin ribs. The unwinding part of the nylon tape forms a spiral groove. Step 7: The resin-ribbed reinforcing bar is wound onto the take-up machine after passing through the traction machine. The finished reinforcing bar is wound together by the traction machine and the take-up machine at a traction speed of 2.0m / min-5.0m / min.

[0013] Compared with the prior art, the advantages of the present invention are as follows: 1. Ribbed hybrid fiber composite reinforcement (reinforcing bar) combines the excellent axial strength and elastic modulus of the core carbon fiber with the outstanding properties of other surface fibers, thus improving the overall performance of the reinforcement. Compared with single fiber reinforcement, it has more comprehensive performance and can be used for more complex application requirements. For example, the surface aramid fiber has high toughness and high impact resistance, the surface glass fiber has good insulation and weather resistance, and the surface basalt fiber has ultra-wide temperature range stability.

[0014] 2. In the molding process of hybrid fiber composite reinforcement, other fibers and carbon fibers are simultaneously drawn, and then positioned by a filament separator during the drawing process, constraining them to the corresponding parts of the reinforcement. This achieves precise structural control of the product. The hybrid fibers are integrally molded and cured, resulting in a smooth and efficient process.

[0015] 3. The method of this invention features integrated molding and a simple process. Using a double-head winding device and a double-head unwinding device for winding and unwinding the nylon strip, the winding, unwinding, and production efficiency can be doubled at the same rotation speed. During double-head winding, the two winding mechanisms work simultaneously, and the nylon strip is symmetrically wound on the surface of the reinforcing material, ensuring symmetrical stress on the pre-formed mixed reinforcing material and making the molding process more stable. Simultaneously, combined with oven heating and curing, the production efficiency far exceeds that of conventional mold-based heating and curing methods, with a maximum production speed exceeding 2.0 m / min. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of the reinforcing bar in an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the process flow for the reinforcement preparation method in an embodiment of the present invention.

[0018] in: 1-Carbon fiber, 2-Other fibers, 3-Resin ribs, 4-Yarn frame, 5-Resin tank, 6-Divider, 7-Bucking ring, 8-Pre-forming mold, 9-Double-head winding equipment, 10-Oven, 11-Double-head unwinding device, 12-Traction machine, 13-Take-up machine. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0020] A hybrid fiber composite reinforcement with ribbed surface includes a core layer of carbon fiber 1 and other fibers 2, the other fibers being aramid fibers and resin ribs 3. The nominal diameter of the reinforcement is 7 mm, and the surface of the reinforcement has continuous spiral epoxy resin ribs with a thickness of 0.3 mm, a width of 6 mm, and a spacing of 3 mm. The elastic modulus of the hybrid reinforcement is greater than 160 GPa.

[0021] A method for preparing a surface-ribbed hybrid fiber composite reinforcement includes the following steps: S1: 23 bundles of carbon fiber and 14 bundles of aramid fiber are drawn out from the yarn frame 4 under uniform tension, wherein the volume content of carbon fiber is controlled at 53.1% and the volume content of aramid fiber is controlled at 20.3%, and the traction speed is 2.0m / min.

[0022] S2: The fiber bundle is orderly drawn into the resin tank 5 to impregnate with epoxy resin. After exiting the resin tank 5, it enters the circular splitting plate 6 for fiber positioning. The carbon fiber of the core layer passes through the positioning hole in the center of the splitting plate 6, and the aramid fiber passes through the positioning hole in the outer layer of the splitting plate 6.

[0023] S3: After passing through the positioning plate 6, the fiber enters the bundle ring 7 and the preforming mold 8, extruding excess epoxy resin. The inner diameter of the preforming mold 8 is 7mm, resulting in a rib blank with a diameter of 7mm. The fiber volume content of the rib blank is 73.4%. The resin matrix is ​​formulated with epoxy resin, curing agent and catalyst.

[0024] S4: While the reinforcing steel blank is being pulled forward, a double-headed winding device 9 is used to continuously, evenly, and symmetrically wind nylon tape onto the reinforcing steel blank. The winding spacing is maintained at 6mm. By adjusting the tension of the double-headed winding device 9, it is ensured that the nylon tape only adheres to the surface of the reinforcing steel blank without constricting it. The fiber bundle orientation on the surface of the reinforcing steel blank remains straight and does not fluctuate. The nylon tape is 2.5mm wide and 0.7mm thick. S5: The rib blank with nylon strips wrapped around its surface is pulled through several ovens 10. The temperature of the ovens 10 is set from low to high, from 140℃ to 220℃. In the first stage of heating in the ovens 10, the epoxy resin inside the rib blank expands and its viscosity decreases after being heated. It begins to overflow from the inside of the rib blank and gradually fills the gaps between the nylon strips. In the second stage of heating in the ovens 10, the epoxy resin undergoes gelation and pre-curing. In the third stage of heating in the ovens 10, the curing process is completed.

[0025] S6: After curing, the reinforcing material is unwound by the double-head unwinding device 11. The unwound part of the nylon tape forms a spiral groove, and the epoxy resin in the gap before the unwound nylon tape on the surface of the reinforcing material forms a spiral resin rib 3.

[0026] S7: The ribbed hybrid fiber composite material reinforcement is wound onto the take-up machine 13 after passing through the traction machine 12. The finished reinforcement is wound together by the traction machine 12 and the take-up machine 13 at a traction speed of 2.0 m / min. Example 2

[0027] A hybrid fiber composite reinforcement with surface ribs includes carbon fiber 1 in the core layer and other fibers 2 on the surface layer, the other fibers being glass fiber and resin ribs 3. The nominal diameter of the reinforcement is 5 mm, and the surface of the reinforcement has continuous spiral epoxy resin ribs with a thickness of 0.2 mm, a width of 5 mm, and a spacing of 2 mm. The hybrid reinforcement has a strength greater than 2600 MPa and an elastic modulus greater than 160 GPa.

[0028] S1: Twelve carbon fiber bundles and eight glass fiber bundles are drawn out from the yarn frame 4 under uniform tension, wherein the volume content of carbon fiber is controlled at 54.3% and the volume content of glass fiber is controlled at 19.5%, and the traction speed is 2.5m / min. S2: The fiber bundle is orderly drawn into the resin tank 5 to impregnate with epoxy resin. After exiting the resin tank 5, it enters the circular splitting plate 6. The core carbon fiber passes through the positioning hole in the center of the splitting plate 6, and the glass fiber passes through the positioning holes distributed on the outer periphery of the splitting plate 6. S3: After the fibers are positioned by the splitting plate 6, they enter the bundling ring 7 and the preforming mold 8, extruding excess epoxy resin. The inner diameter of the preforming mold 8 is 5mm, resulting in a rib blank with a diameter of 5mm. The fiber volume content of the rib blank is 73.8%. S4: While the reinforcing steel blank is being pulled forward, a double-headed winding device 9 is used to continuously, evenly, and symmetrically wind nylon tape onto the reinforcing steel blank. The winding spacing is maintained at 5mm. By adjusting the tension of the double-headed winding device 9, it is ensured that the nylon tape only adheres to the surface of the reinforcing steel blank without constricting it. The fiber bundle orientation on the surface of the reinforcing steel blank remains straight and does not fluctuate. The nylon tape is 2.0mm wide and 0.6mm thick. S5: The rib blank with nylon strips wrapped around its surface is pulled through several ovens 10. The temperature of the ovens 10 is set from low to high, from 140℃ to 220℃. In the first stage of heating in the ovens 10, the epoxy resin inside the rib blank expands and its viscosity decreases after being heated. It begins to overflow from the inside of the rib blank and gradually fills the gaps between the nylon strips. In the second stage of heating in the ovens 10, the epoxy resin undergoes gelation and pre-curing. In the third stage of heating in the ovens 10, the curing process is completed. S6: After curing, the reinforcing material is unwound by the double-head unwinding device 11. The unwound part of the nylon tape forms a spiral groove, and the epoxy resin in the gap before the unwound nylon tape on the surface of the reinforcing material forms a spiral resin rib 3.

[0029] S7: The ribbed hybrid fiber composite material reinforcement is wound onto the take-up machine 13 after passing through the traction machine 12. The finished reinforcement is wound together by the traction machine 12 and the take-up machine 13 at a traction speed of 2.5 m / min.

[0030] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A surface-ribbed hybrid fiber composite reinforcement, characterized in that: The reinforcing material includes carbon fiber, other fibers, and a resin matrix. The carbon fiber and other fibers are embedded inside the resin matrix, and the surface of the reinforcing material has spiral resin ribs.

2. The surface-ribbed hybrid fiber composite reinforcement according to claim 1, characterized in that: The other fibers are selected from one or more of aramid fibers, basalt fibers, and glass fibers.

3. The surface-ribbed hybrid fiber composite reinforcement according to claim 1, characterized in that: The carbon fibers are distributed in the core of the reinforcing material, while other fibers are distributed on the outer periphery of the carbon fibers.

4. The surface-ribbed hybrid fiber composite reinforcement according to claim 1, characterized in that: The diameter of the reinforcing bar is 2mm-36mm, the volume content of carbon fiber is 52%-57%, and the volume content of other fibers is 19%-22%.

5. The surface-ribbed hybrid fiber composite reinforcement according to claim 1, characterized in that: The thickness of the resin rib is 1%-6% of the diameter of the reinforcing bar, the width of the resin rib is in the range of 4mm-15mm, and the pitch of the resin rib is 2mm-10mm.

6. The surface-ribbed hybrid fiber composite reinforcement according to claim 1, characterized in that: Longitudinal elastic modulus of reinforcing bars E C The following calculation model was used for adjustment. The calculation model follows the principle of iso-strain in the micromechanics of unidirectional composite materials. The required number of fibers and fiber volume content were calculated using this calculation model. ； In the formula, T cf The fineness of carbon fiber, or carbon fiber bundle, is measured in g / km. N cf The number of carbon fiber bundles; ρ cf This refers to the density of the carbon fiber bundle, expressed in g / cm³. 3 ; d is the diameter of the reinforcing bar, in mm; T sf This refers to the fineness of other fibers, i.e., other fiber bundles, expressed in g / km. N sf For the number of other fiber bundles; ρ sf The density of other fiber bundles, in g / cm³ 3 ; E cf This represents the longitudinal elastic modulus of the carbon fiber bundle, expressed in GPa. E sf Let q be the longitudinal elastic modulus of the other fiber bundles, in GPa; E c This represents the elastic modulus of the reinforcing bar, expressed in GPa. E m for The elastic modulus of the resin matrix, expressed in GPa.

7. A method for preparing the surface-ribbed hybrid fiber composite reinforcement as described in claim 1, characterized in that: It includes the following steps: Step 1: Draw out several bundles of carbon fiber and other fiber bundles from the yarn frame, and control the tension of each fiber bundle to be uniform. Step 2: The carbon fiber bundles and other fiber bundles are drawn into the resin tank in an orderly manner to impregnate the resin, so that the fiber bundles are fully impregnated with the resin in the impregnation tank. After exiting the resin tank, they enter a circular splitting plate for positioning. The carbon fiber bundles located in the core of the reinforcing material pass through the splitting hole in the center of the splitting plate, while the other fiber bundles located near the surface of the reinforcing material pass through the outer splitting hole on the splitting plate. Step 3: After the fiber bundle passes through the splitting plate, it passes through the bundle-gathering ring and the preforming mold, and the excess resin is extruded to obtain a rib blank with a predetermined cross-section of circular size. The inner diameter of the preforming mold is 2mm-36mm. Step 4: While pulling the reinforcing steel blank forward, wrap nylon tape around the reinforcing steel blank. Use a double-ended wrapping method to continuously, evenly, and symmetrically wrap the nylon tape around the reinforcing steel blank from top to bottom. Keep the wrapping spacing in the range of 4mm-15mm and control the wrapping tension. The nylon tape should only be in contact with the surface of the reinforcing steel blank without tightening it. Keep the carbon fiber bundle orientation on the surface of the reinforcing steel blank straight. The width of the nylon tape is 2mm-10mm and the thickness is 0.2mm-1.5mm. Step 5: The rib blank with nylon strips wrapped around its surface is pulled through several ovens. The temperature of the ovens is set from low to high, from 140℃ to 220℃. In the first stage of oven heating, the resin inside the rib blank expands and its viscosity decreases due to the heat. It begins to overflow from the inside of the rib blank and gradually fills the gaps between the nylon strips. In the second stage of oven heating, the resin undergoes gelation and pre-curing. In the third stage of oven heating, the full curing process is completed. The thickness of the resin ribs is affected by the heating temperature and time in the first stage. The thickness of the resin ribs can be controlled by controlling the oven temperature and length. Step 6: After the surface ribs have been cured, air-cool them and unwind the nylon tape using a double-head unwinding method. The unwinding part of the nylon tape forms a spiral groove, exposing the resin ribs in the gaps between the nylon tapes on the surface of the ribs, forming spiral resin ribs. The unwinding part of the nylon tape forms a spiral groove. Step 7: The resin-ribbed reinforcing bar is wound onto the take-up machine after passing through the traction machine. The finished reinforcing bar is wound together by the traction machine and the take-up machine at a traction speed of 2.0m / min-5.0m / min.

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