Method for controlling properties of pultruded composite material and pultruded composite material

Abstract

The present application relates to the technical field of pultruded composite material, and particularly relates to a performance regulation method of pultruded composite material, which adopts twisted fiber bundle and untwisted fiber bundle combination layout to form a fiber bundle stack structure of pultruded composite material; the twisted fiber bundle adopts unidirectional twisted fiber bundle; a plurality of twisted fiber bundles are distributed on the outer layer of the fiber bundle stack structure and form a closed ring layer; the internal space of the closed ring layer is filled by a plurality of untwisted fiber bundles. The present application also relates to a pultruded composite material obtained based on the performance regulation method, which comprises: a closed ring layer formed by a plurality of twisted fiber bundles, the twisted fiber bundle adopts unidirectional twisted fiber bundle; a stack formed by a plurality of untwisted fiber bundles; and the stack is filled in the internal space of the closed ring layer. Balanced multi-dimensional mechanical performance can be freely adjusted, and the pultruded composite material with balanced multi-dimensional mechanical performance and commercial cost performance can be obtained.

Description

Technical Field

[0001] This invention relates to the field of pultrusion composite materials technology, and in particular to a method for performance control of pultrusion composite materials, and a pultrusion composite material obtained based on the performance control method. Background Technology

[0002] When constructing bridges or power grids across large spans of waterways and in mountainous areas, as well as large-scale equipment such as floating power stations, anchor cables for land-based infrastructure, mooring cables for deep-sea platforms, wind turbine poles, and tension cables for rail transit power grids, continuous, long-length, high-performance structures are often required to support the stable and long-term service of the equipment. Traditional metal structural components suffer from increasingly significant drawbacks, including excessive weight, low load-bearing efficiency, limited service life, weak corrosion resistance, and insufficient fatigue performance. Pultruded composite core materials have become the most promising new technology product for these applications. However, the reinforcements in traditional pultruded composite materials are mostly 0° fiber bundles, braided tubing, or multi-layer two-dimensional fabric stacks. These structures suffer from inherent defects such as low fiber-resin interface bonding strength, insufficient torsional toughness, weak axial shear and bending resistance, susceptibility to large-scale rapid splitting under radial loads, difficulty in controlling internal porosity defects, and unbalanced multi-dimensional properties. Failure modes are primarily structural delamination and core-skin delamination. Furthermore, adding additional processes such as braiding, winding, and stranding presents objective problems such as complex processes, low efficiency, high costs, and limited adjustability of multi-dimensional properties.

[0003] Therefore, given that existing pultruded composite materials are insufficient to meet the high reliability requirements under the complex working conditions described above, the market urgently needs to develop new technologies and products that offer commercial cost-effectiveness and allow for free control over the multidimensional performance imbalances (axial and off-axial performance imbalances) of pultruded composite materials, in order to better meet the stringent application requirements of equipment in the aforementioned critical fields. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a method for performance control of pultruded composite materials, which can achieve free and adjustable balanced multidimensional mechanical properties and obtain pultruded composite materials with balanced multidimensional mechanical properties and commercial cost performance.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention provides a method for controlling the performance of pultruded composite materials, which adopts a combination of twisted fiber bundles and untwisted fiber bundles to form a fiber bundle stack structure of pultruded composite materials; the twisted fiber bundles are unidirectional twisted fiber bundles; multiple twisted fiber bundles are distributed on the outer layer of the fiber bundle stack structure and form a closed ring layer; the internal space of the closed ring layer is filled by multiple untwisted fiber bundles.

[0007] Preferably, the outer surface of the closed loop forms the surface of the fiber bundle stack structure; or, multiple strands of untwisted fiber bundles are wrapped around the outer surface of the closed loop to form a surface layer, the untwisted fiber bundles of the surface layer fill the uneven texture of the outer surface of the closed loop, and the outer surface of the surface layer forms the surface of the fiber bundle stack structure.

[0008] Preferably, adjacent twisted fiber bundles of the closed loop are in direct contact; or, untwisted fiber bundles are filled between adjacent twisted fiber bundles of the closed loop.

[0009] Preferably, the multi-strand twisted fiber bundles are distributed in a single layer on the outer layer of the fiber bundle stack structure, and the twist directions of adjacent twisted fiber bundles are opposite; or, the multi-strand twisted fiber bundles are distributed in multiple layers on the outer layer of the fiber bundle stack structure, the twist directions of the twisted fiber bundles in the same layer are in the same direction, and the twist directions of the twisted fiber bundles in adjacent layers are opposite.

[0010] Preferably, when the minimum wall thickness of the fiber bundle stack structure is less than 10 mm, the number of layers of multi-strand twisted fiber bundles distributed on the outer layer of the fiber bundle stack structure does not exceed 2; when the minimum wall thickness of the fiber bundle stack structure is 10 mm to 30 mm, the number of layers of multi-strand twisted fiber bundles distributed on the outer layer of the fiber bundle stack structure does not exceed 3; when the minimum wall thickness of the fiber bundle stack structure is 30 mm to 50 mm, the number of layers of multi-strand twisted fiber bundles distributed on the outer layer of the fiber bundle stack structure does not exceed 4.

[0011] Preferably, the twist angle of the twisted fiber bundle is 5°-30°.

[0012] The present invention also provides a pultruded composite material obtained based on the above-described method for controlling the performance of pultruded composite materials, comprising: a closed ring layer formed by multiple twisted fiber bundles, wherein the twisted fiber bundles are unidirectional twisted fiber bundles; an accumulation body formed by multiple untwisted fiber bundles; and the accumulation body filling the internal space of the closed ring layer.

[0013] Preferably, it further includes: a surface layer formed of multiple strands of untwisted fiber bundles, the surface layer covering the outer surface of the closed loop layer and filling the uneven texture of the outer surface of the closed loop layer.

[0014] Preferably, adjacent twisted fiber bundles of the closed loop are in direct contact or filled with untwisted fiber bundles.

[0015] Preferably, the closed loop layer includes a layer of twisted fiber bundles, with adjacent twisted fiber bundles twisted in opposite directions; or, the closed loop layer includes multiple layers of twisted fiber bundles, with twisted fiber bundles in the same layer twisted in the same direction, and twisted fiber bundles in adjacent layers twisted in opposite directions.

[0016] Compared with the prior art, the present invention has significant progress:

[0017] This invention distributes twisted fiber bundles on the outer layer of a fiber bundle stack structure. The twisted fiber bundles are unidirectional twisted fiber bundles, while untwisted fiber bundles are distributed on the inner layer of the fiber bundle stack structure. This arrangement forms a fiber bundle stack structure for pultruded composite materials, which has the following advantages:

[0018] (1) High cost-effectiveness in commercial applications. Compared with existing technologies that only use untwisted fiber bundles to form untwisted fiber bundle stacks or add weaving, winding, twisting, and coating processes on the basis of pultrusion process according to design needs, the present invention uses twisted fiber bundles distributed on the outer layer of the fiber bundle stack structure. The process cost generated by twisting the fiber bundles is a raw material processing cost and does not need to be linked with the pultrusion molding process. At the same time, the twisting technology is more mature than the combination of the above processes and pultrusion technology, and the processing cost is significantly reduced compared with the equipment construction cost of the above processes. Moreover, the twisting can be provided by the raw material supplier or handled by ourselves, which is flexible.

[0019] (2) Strong controllability of distribution structure. The distribution design of twisted fiber bundles on the outer layer of the fiber bundle stack structure can be freely designed according to the overall performance requirements of the pultruded composite material. For example, for parts with high requirements for radial compression resistance, bending resistance and impact resistance, the distribution of twisted fiber bundles can be appropriately increased. For parts with weaker requirements, the distribution of twisted fiber bundles can be appropriately reduced. However, regardless of whether the distribution of twisted fiber bundles is increased or decreased, the axial direction of the pultruded composite material is continuous, and there is no fiber breakage phenomenon inside. Moreover, the areas with more twisted fiber bundles and the areas with fewer twisted fiber bundles can be gradually and alternately designed to achieve a gradual transition of customized performance within the overall pultruded composite material. Ultimately, the overall pultruded composite material can achieve continuous changes in certain directional design properties within a certain area, avoiding the stepwise changes in performance.

[0020] (3) Twisting technology can be used to control the failure mechanism of pultruded composites. By utilizing the helical effect of the fiber filaments generated by twisting, the unidirectional deep crack propagation mode in existing products can be transformed into a divergent crack propagation mode. At the same time, multi-layer design of crack propagation blocking sites can be carried out along the wall thickness direction of the pultruded composite, thereby improving the radial compression resistance, bending resistance and impact resistance of the pultruded composite.

[0021] (4) It plays a guiding role in the upgrading and iterative application of existing technologies and products. This invention can not only meet the acceptable production cost of industrial pultruded composite materials, but also significantly improve the axial mechanical properties of pultruded composite materials. It plays a guiding role in breaking through the bottleneck of existing pultruded composite material application technology and has great industrial commercial value.

[0022] Therefore, the performance control method of pultruded composite materials of the present invention can achieve balanced and freely adjustable multidimensional mechanical properties, and obtain pultruded composite materials with balanced multidimensional mechanical properties and commercial cost performance. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of the first layout of twisted fiber bundles and untwisted fiber bundles in the performance control method of pultruded composite materials according to an embodiment of the present invention.

[0024] Figure 2 This is a cross-sectional schematic diagram of the second layout of twisted fiber bundles and untwisted fiber bundles in the performance control method of pultruded composite materials according to an embodiment of the present invention.

[0025] Figure 3 This is a cross-sectional schematic diagram of the third layout of twisted fiber bundles and untwisted fiber bundles in the performance control method of pultruded composite materials according to an embodiment of the present invention.

[0026] Figure 4 This is a cross-sectional schematic diagram of the fourth layout of twisted fiber bundles and untwisted fiber bundles in the performance control method of pultruded composite materials according to an embodiment of the present invention.

[0027] Figure 5 This is a cross-sectional schematic diagram of an untwisted fiber bundle stack as a comparative example in an embodiment of the present invention.

[0028] The reference numerals in the attached figures are explained as follows:

[0029] 100. Fiber bundle stack structure; 101. Closed loop; 102. Stack; 103. Surface layer; 1. Twisted fiber bundle; 2. Untwisted fiber bundle; 200. Untwisted fiber bundle stack. Detailed Implementation

[0030] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] like Figures 1 to 4 The image shows an embodiment of the performance control method for pultruded composite materials provided by the present invention.

[0035] Pultruded composites are formed by the curing of fibers and resin. Fibers are bundled together to form fiber bundles, and these fiber bundles are stacked to form a stacked structure, constituting the reinforcement within the pultruded composite. In the pultrusion composite manufacturing process, several fiber bundles are unwound from the yarn frame and enter the resin impregnation stage. Then, the spacing between the fiber bundles is gradually reduced by a pre-forming shrinkage device, and finally, they enter the die orifice to complete the final outer diameter shaping and heat curing. At the die orifice, the fiber bundles are stacked together. Existing technology primarily uses untwisted fiber bundles 2, which are fiber bundles formed by the bundled fibers along a uniform axial direction during bundling, also known as 0° fiber bundles. Therefore, under movement and extrusion, the fibers within the untwisted fiber bundle 2 will slide and mix together to form a whole. The cross-sectional structure of the final untwisted fiber bundle stack 200 formed by the die is as follows... Figure 5 As shown in the figure, the curved lines represent the contact interfaces between the individual untwisted fiber bundles 2.

[0036] In the performance control method of pultruded composite materials in this embodiment, the types of fibers and resins used in pultruded composite materials are not limited. The core lies in the improved design of the fiber bundle layout, with the aim of optimizing the multidimensional mechanical properties of pultruded composite materials.

[0037] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the performance control method of the pultruded composite material in this embodiment is to form a fiber bundle stack structure 100 of the pultruded composite material by combining twisted fiber bundles 1 and untwisted fiber bundles 2. The untwisted fiber bundles 2 are existing 0° fiber bundles. The twisted fiber bundles 1 are helical or cylindrical fiber bundles formed by twisting the fiber filaments around the central axis during bundling. The twisted fiber bundles 1 are unidirectional twisted fiber bundles. Multiple twisted fiber bundles 1 are distributed on the outer layer of the fiber bundle stack structure 100, forming a closed ring layer 101. The internal space of the closed ring layer 101 is filled by multiple untwisted fiber bundles 2, forming a stack 102.

[0038] The performance control method of the pultruded composite material in this embodiment distributes the twisted fiber bundle 1 on the outer layer of the fiber bundle stack structure 100. The twisted fiber bundle 1 is a unidirectional twisted fiber bundle, and the untwisted fiber bundle 2 is distributed on the inner layer of the fiber bundle stack structure 100. The fiber bundle stack structure 100 of the pultruded composite material is formed in this layout, which has the following advantages.

[0039] (1) High commercial cost performance. Compared with the existing technology that only uses untwisted fiber bundles 2 to form untwisted fiber bundle stacks 200 or adds weaving, winding, twisting, and coating processes on the basis of pultrusion process according to design needs, the performance control method of pultruded composite material in this embodiment uses twisted fiber bundles 1 distributed on the outer layer of fiber bundle stack structure 100. The process cost generated by fiber bundle twisting is the processing of raw materials and does not need to be linked with the pultrusion molding process. At the same time, the twisting technology is more mature than the combination of the above processes and pultrusion technology, and the processing cost is significantly reduced compared with the equipment construction cost of the above processes. Moreover, the twisting can be provided by the raw material supplier or handled by ourselves, which is flexible.

[0040] (2) Strong controllability of distribution structure. The distribution design of twisted fiber bundle 1 on the outer layer of fiber bundle stack structure 100 can be freely designed according to the overall performance requirements of pultruded composite material. For example, for parts with high requirements for radial compression resistance, bending resistance and impact resistance, the distribution amount of twisted fiber bundle 1 can be appropriately increased. For parts with weaker requirements, the distribution amount of twisted fiber bundle 1 can be appropriately reduced. However, regardless of whether the distribution amount of twisted fiber bundle 1 is increased or decreased, the axial direction of the pultruded composite material is continuous, and there is no fiber breakage phenomenon inside. Moreover, the areas with more twisted fiber bundle 1 and the areas with less twisted fiber bundle 1 can be gradually and alternately designed to achieve a gradual transition of customized performance within the overall pultruded composite material. Ultimately, the overall pultruded composite material can achieve continuous changes in certain directional design performances in a certain area, avoiding the stepwise changes in performance.

[0041] (3) Twisting technology can be used to control the failure mechanism of pultruded composites. By utilizing the helical effect of the fiber filaments generated by twisting, the unidirectional deep crack propagation mode in existing products can be transformed into a divergent crack propagation mode. At the same time, multi-layer design of crack propagation blocking sites can be carried out along the wall thickness direction of the pultruded composite, thereby improving the radial compression resistance, bending resistance and impact resistance of the pultruded composite.

[0042] (4) It plays a guiding role in the upgrading and iterative application of existing technologies and products. The performance control method of pultruded composite materials in this embodiment can not only meet the acceptable production cost of industrial pultruded composite materials, but also significantly improve the axial mechanical properties of pultruded composite materials. It plays a guiding role in breaking through the bottleneck of existing pultruded composite material application technology and has great industrial commercial value.

[0043] Therefore, the performance control method of pultruded composite materials in this embodiment can achieve balanced and freely adjustable multidimensional mechanical properties, and obtain pultruded composite materials with balanced multidimensional mechanical properties and commercial cost-effectiveness.

[0044] like Figure 1 As shown, in one embodiment, the outer surface of the closed ring 101 forms the surface of the fiber bundle stack structure 100, that is, multiple twisted fiber bundles 1 are arranged on the outermost layer of the fiber bundle stack structure 100 to form the surface layer of the pultruded composite material. In this embodiment, since the twisted fiber bundles 1 are placed on the surface layer of the pultruded composite material, when the pultruded composite material is under load, the outermost twisted fiber bundles 1 bear the load first. When cracks occur on the surface of the fiber bundle stack structure 100 of the pultruded composite material (the outer surface of the closed ring 101), the cracks will spatially diverge and propagate along the pre-twisting direction of the twisted fiber bundles 1. This crack propagation failure mode changes the unidirectional deep diffusion mode under the existing technology product structure and improves the radial compression resistance, bending resistance and impact resistance of the pultruded composite material. However, on the other hand, the twisted fiber bundles 1 become rounded and compact due to twisting, and the surface is an irregular surface with uneven texture. The uneven texture of the irregular surface of the twisted fiber bundles 1 increases the surface roughness of the pultruded composite material, resulting in the risk of stress concentration and instability failure of the pultruded composite material surface.

[0045] like Figure 2 , Figure 3 and Figure 4As shown, in another embodiment, multiple strands of untwisted fiber bundles 2 are coated on the outer surface of the closed ring layer 101 to form a surface layer 103. The untwisted fiber bundles 2 of the surface layer 103 fill the uneven texture of the outer surface of the closed ring layer 101, and the outer surface of the surface layer 103 forms the surface of the fiber bundle stack structure 100. That is, multiple strands of twisted fiber bundles 1 are arranged in the second outermost layer of the fiber bundle stack structure 100 to form the second outermost layer of the pultruded composite material. A distribution structure of multiple strands of untwisted fiber bundles 2 is added to the surface of this second outermost layer to form the surface layer 103. The surface layer 103 is arranged in the outermost layer of the fiber bundle stack structure 100 to form the surface layer of the pultruded composite material. Compared to the layout where the multi-strand twisted fiber bundle 1 arranged on the outermost layer of the fiber bundle stack structure 100 is used as the surface layer of the pultruded composite material, this embodiment adds a surface layer 103 structure formed by multi-strand untwisted fiber bundles 2 to the surface of the closed ring layer 101 formed by the multi-strand twisted fiber bundle 1. By utilizing the characteristic that the untwisted fiber bundles 2 can loosely fill the uneven texture of the surface of the twisted fiber bundle 1, the risk of stress concentration failure during load contact caused by the uneven and rough surface of the pultruded composite material due to the direct formation of the surface layer of the twisted fiber bundle 1 is weakened.

[0046] like Figure 1 , Figure 2 and Figure 4 As shown, in one embodiment, adjacent twisted fiber bundles 1 of the closed ring 101 are in direct contact, and the internal space of the closed ring 101 formed by multiple twisted fiber bundles 1 is completely filled by multiple untwisted fiber bundles 2.

[0047] like Figure 3 As shown, in another embodiment, untwisted fiber bundles 2 are filled between adjacent twisted fiber bundles 1 of the closed ring layer 101, such that each twisted fiber bundle 1 of the closed ring layer 101 is spaced by an untwisted fiber bundle 2. In particular, when a surface layer 103 formed by multiple untwisted fiber bundles 2 is coated on the outer surface of the closed ring layer 101, each twisted fiber bundle 1 of the closed ring layer 101 is spaced by untwisted fiber bundles 2 around its perimeter. Compared with direct contact between adjacent twisted fiber bundles 1 of the closed ring layer 101, this embodiment, by filling the twisted fiber bundles 1 with untwisted fiber bundles 2 to create spacing between each twisted fiber bundle 1, can weaken the risk of internal stress concentration caused by the excessive accumulation of rounded and surface-rough twisted fiber bundles 1. This risk mainly comes from internal pores, which originate from resin defects and are more likely to grow on the rounded surface of the twisted fiber bundles 1.

[0048] Figures 1 to 3 The following shows three specific arrangements of twisted fiber bundles 1 and untwisted fiber bundles 2 in the performance control method of pultruded composite materials in this embodiment.

[0049] like Figure 1As shown, the first layout is as follows: multiple twisted fiber bundles 1 are arranged on the outermost layer of the fiber bundle stack structure 100 to form a closed ring layer 101. The outer surface of the closed ring layer 101 forms the surface of the fiber bundle stack structure 100. Adjacent twisted fiber bundles 1 in the closed ring layer 101 are in direct contact. The internal space of the closed ring layer 101 formed by the multiple twisted fiber bundles 1 is completely filled by multiple untwisted fiber bundles 2. This layout changes the unidirectional deep crack propagation mode in existing products to a spatial divergent crack propagation mode along the pre-twisting direction of the twisted fiber bundles 1, thereby improving the radial compression resistance, bending resistance, and impact resistance of the pultruded composite material.

[0050] like Figure 2 As shown, the second layout is as follows: multi-strand twisted fiber bundles 1 are arranged in the outermost layer of the fiber bundle stack structure 100 to form a closed ring layer 101. The outer surface of the closed ring layer 101 is covered with multi-strand untwisted fiber bundles 2 to form a surface layer 103. The outer surface of the surface layer 103 forms the surface of the fiber bundle stack structure 100. Adjacent twisted fiber bundles 1 of the closed ring layer 101 are in direct contact. The internal space of the closed ring layer 101 formed by the multi-strand twisted fiber bundles 1 is completely filled by the stacked multi-strand untwisted fiber bundles 2. This layout utilizes the untwisted fiber bundles 2 to loosely fill the uneven texture of the twisted fiber bundles 1 on the surface of the closed ring layer 101, which weakens the risk of stress concentration failure caused by the uneven surface roughness of the pultruded composite material in the first layout. Based on the first layout, it improves the radial compression resistance and bending resistance of the pultruded composite material, but the improvement in impact resistance is not significant.

[0051] like Figure 3 As shown, the third layout is a derivative structure of the second layout. Based on the second layout, untwisted fiber bundles 2 are filled between adjacent twisted fiber bundles 1 of the closed ring 101, so that each twisted fiber bundle 1 of the closed ring 101 is surrounded by untwisted fiber bundles 2. This layout mitigates the risk of internal stress concentration caused by the excessive accumulation of rounded, unevenly textured twisted fiber bundles 1. It represents an optimization of the internal homogeneity and a refined control of performance based on the second layout.

[0052] In the various layouts of twisted fiber bundles 1 and untwisted fiber bundles 2 described above, having too many or too few layers of multi-strand twisted fiber bundles 1 on the outer layer of the fiber bundle stack structure 100 will not achieve the desired effect. Therefore, it is necessary to design a matching scheme for the number of layers of multi-strand twisted fiber bundles 1 on the outer layer of the fiber bundle stack structure 100. Furthermore, if all multi-strand twisted fiber bundles 1 use twisted fiber bundles 1 with a single twist direction, it will have a certain impact on the overall torsional resistance. Therefore, it is also necessary to design the twist direction of the twisted fiber bundles 1 in each layer.

[0053] like Figures 1 to 3 As shown, in one embodiment, the multi-strand twisted fiber bundle 1 is distributed in a single layer on the outer layer of the fiber bundle stack structure 100, and the twist directions of adjacent twisted fiber bundles 1 are opposite.

[0054] like Figure 4 As shown, in another embodiment, multiple twisted fiber bundles 1 are distributed in multiple layers on the outer layer of the fiber bundle stack structure 100. The twisted fiber bundles 1 in the same layer are twisted in the same direction, while the twisted fiber bundles 1 in adjacent layers are twisted in opposite directions. Untwisted fiber bundles 2 can be filled between adjacent twisted fiber bundle layers for spacing.

[0055] Increasing the number of layers of multi-strand twisted fiber bundles 1 on the outer layer of the fiber bundle stack structure 100, through the design of a closed ring structure 101 with multiple layers of twisted fiber bundles 1, essentially increases the number of trigger points that alter the unidirectional deep propagation of cracks, and gradually distributes these trigger points along the wall thickness direction of the pultruded composite material. However, more layers of twisted fiber bundles 1 are not necessarily better. Too many layers of twisted fiber bundles 1 can significantly weaken the axial tensile and compressive strength of the pultruded composite material, while too few layers of twisted fiber bundles 1 result in only a slight improvement in the radial compression, bending, and impact resistance of the pultruded composite material. This slight improvement is particularly noticeable in pultruded composite materials with large wall thicknesses.

[0056] Therefore, the preferred design for the number of layers of the twisted fiber bundle 1 is as follows: when the minimum wall thickness of the fiber bundle stack structure 100 is less than 10 mm, the number of layers of the multi-strand twisted fiber bundle 1 distributed on the outer layer of the fiber bundle stack structure 100 does not exceed 2; when the minimum wall thickness of the fiber bundle stack structure 100 is 10 mm to 30 mm, the number of layers of the multi-strand twisted fiber bundle 1 distributed on the outer layer of the fiber bundle stack structure 100 does not exceed 3; when the minimum wall thickness of the fiber bundle stack structure 100 is 30 mm to 50 mm, the number of layers of the multi-strand twisted fiber bundle 1 distributed on the outer layer of the fiber bundle stack structure 100 does not exceed 4. The minimum wall thickness of the fiber bundle stack structure 100 refers to the minimum thickness dimension on the cross-section of the fiber bundle stack structure 100.

[0057] Figure 4 This embodiment illustrates a specific multi-layered arrangement of the twisted fiber bundle 1 in the performance control method for pultruded composite materials: (as described above) Figure 2 Based on the second layout shown, the multi-strand twisted fiber bundle 1 is distributed in two layers on the outer layer of the fiber bundle stack structure 100 to form a closed ring layer 101, and the two twisted fiber bundle layers are filled with untwisted fiber bundles 2 for spacing.

[0058] It should be noted that, Figures 1 to 4The examples shown all use pultruded composite materials with a square cross-section as an example. However, in this embodiment, the shape of the pultruded composite material is not limited. Regardless of the shape of the pultruded composite material, as long as the pultruded composite material has a certain through wall thickness, within the wall thickness range, the performance control method of the pultruded composite material in this embodiment can obtain a structure with a combination of twisted fiber bundle 1 and untwisted fiber bundle 2, thereby realizing multi-dimensional performance control of the pultruded composite material.

[0059] In this embodiment, the twist angle of the twisted fiber bundle 1 is preferably 5°-30°.

[0060] Based on the performance control method of pultruded composite materials of the present invention, the present invention also provides a pultruded composite material. The pultruded composite material of this embodiment is obtained based on the performance control method of pultruded composite materials described above in this embodiment, and has a fiber bundle distribution structure that matches the arrangement of twisted fiber bundle 1 and untwisted fiber bundle 2 in the performance control method of pultruded composite materials described above.

[0061] like Figures 1 to 4 As shown, the pultruded composite material of this embodiment includes a closed ring layer 101 and an assembly 102. The closed ring layer 101 is formed by multiple twisted fiber bundles 1, which are unidirectional twisted fiber bundles. The assembly 102 is formed by multiple untwisted fiber bundles 2, and the assembly 102 fills the internal space of the closed ring layer 101. That is, the fiber bundle stack structure 100 of the pultruded composite material is formed by the combination and arrangement of twisted fiber bundles 1 and untwisted fiber bundles 2, with the twisted fiber bundles 1 distributed in the outer layer of the fiber bundle stack structure 100 and the untwisted fiber bundles 2 distributed in the inner layer of the fiber bundle stack structure 100.

[0062] like Figure 1 As shown, the outer surface of the closed loop 101 can serve as the surface of the fiber bundle stack structure 100. Alternatively, as... Figure 2 , Figure 3 and Figure 4 As shown, preferably, the pultruded composite material of this embodiment further includes a surface layer 103, which is formed by multiple strands of untwisted fiber bundles 2. The surface layer 103 covers the outer surface of the closed ring layer 101 and fills the uneven texture of the outer surface of the closed ring layer 101. The surface layer 103 serves as the surface of the fiber bundle stack structure 100.

[0063] like Figure 1 , Figure 2 and Figure 4 As shown, adjacent twisted fiber bundles 1 of the closed loop 101 can be in direct contact. Or, as... Figure 3 As shown, preferably, untwisted fiber bundles 2 are filled between adjacent twisted fiber bundles 1 of the closed loop layer 101.

[0064] like Figure 1 , Figure 2 and Figure 3 As shown, the closed loop layer 101 may include a layer of twisted fiber bundles, with adjacent twisted fiber bundles 1 having opposite twist directions. Alternatively, as... Figure 4 As shown, the closed ring layer 101 may include multiple layers of twisted fiber bundles, the twisted fiber bundles 1 in the same layer are in the same direction, and the twisted fiber bundles 1 in adjacent layers are in opposite directions.

[0065] The following uses pultruded composite beams as an example to test the performance of three pultruded composite material samples and two comparative sample samples obtained by the performance control method of pultruded composite materials described above in the embodiments of the present invention. The performance of each sample is shown in Table 1 below.

[0066] The pultruded composite beam is made of 15 strands of 12K T700 grade carbon fiber, 10 strands of 6K T700 carbon fiber, and epoxy resin. The outer diameter of the composite beam is approximately 4mm*4mm. It is fabricated using... Figure 5 The prior art shown is only a comparative example 1 of the 0° fiber bundle layout; the embodiments of the present invention are as follows: Figure 1 Sample 1 with the first layout shown; The embodiment of the present invention as shown Figure 2 Sample 2 with the second layout shown; using the embodiments of the present invention as shown Figure 3 Sample 3, which shows the third layout; and samples employing the same layout as those in the embodiments of the present invention. Figure 1 Comparative Example 2 shows a distribution structure that is completely opposite to the first layout (the interior of the fiber bundle stack is entirely composed of twisted fiber bundles, and the exterior is composed of untwisted fiber bundles).

[0067] In sample 1, the twist angle of the twisted fiber bundle 1 is 13°, the outer layer is 10 strands of 6K twisted carbon fiber bundles, and the inner layer is filled with 15 strands of 12K untwisted carbon fiber bundles.

[0068] In sample 2, the twist angle of the twisted fiber bundle 1 is 13°, the outermost layer is 10 strands of 6K untwisted carbon fiber bundle, the next outermost layer is 10 strands of 6K twisted carbon fiber bundle, and the interior is filled with 10 strands of 12K untwisted carbon fiber bundle.

[0069] In sample 3, the twist angle of the twisted fiber bundle 1 is 13°. The outermost layer is 10 strands of 6K untwisted fiber bundle, the next outermost layer is 10 strands of 6K twisted carbon fiber bundle, the twisted carbon fiber bundles are separated by 10 strands of 6K untwisted fiber bundle, and the interior is filled with 5 strands of 12K untwisted carbon fiber bundle.

[0070] In Comparative Example 2, the twist angle of the twisted fiber bundle is 13°, the outer layer is 10 strands of 6K untwisted carbon fiber bundles, and the inner layer is filled with 15 strands of 12K twisted carbon fiber bundles.

[0071] Table 1 Performance of each sample

[0072]

[0073] As shown in Table 1, the three pultruded composite material samples 1-3 obtained based on the performance control method of the pultruded composite material described in the embodiments of the present invention exhibit significantly improved tensile strength, radial compression resistance, flexural strength, and impact resistance compared to Comparative Example 1, which uses only a 0° fiber bundle layout in the prior art. Conversely, Comparative Example 4, which uses a distribution structure opposite to the performance control method of the pultruded composite material described in the embodiments of the present invention, shows decreased tensile strength, radial compression resistance, flexural strength, and impact resistance compared to Comparative Example 1, which uses only a 0° fiber bundle layout in the prior art. Therefore, the performance control method of the pultruded composite material described in the embodiments of the present invention can achieve balanced and freely adjustable improvement of multidimensional mechanical properties, resulting in pultruded composite materials with balanced multidimensional mechanical properties and commercial cost-effectiveness.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling the performance of pultruded composite materials, characterized in that, A fiber bundle stack structure (100) of pultruded composite material is formed by combining twisted fiber bundles (1) and untwisted fiber bundles (2). The twisted fiber bundle (1) is a unidirectional twisted fiber bundle; Multiple twisted fiber bundles (1) are distributed on the outer layer of the fiber bundle stack structure (100) and form a closed ring (101). The internal space of the closed ring (101) is filled by stacked bundles of the untwisted fibers (2).

2. The method for controlling the performance of pultruded composite materials according to claim 1, characterized in that, The outer surface of the closed ring (101) forms the surface of the fiber bundle stack structure (100); Alternatively, multiple strands of untwisted fiber bundles (2) are wrapped around the outer surface of the closed ring (101) to form a surface layer (103). The untwisted fiber bundles (2) of the surface layer (103) fill the uneven texture of the outer surface of the closed ring (101), and the outer surface of the surface layer (103) forms the surface of the fiber bundle stack structure (100).

3. The method for controlling the performance of pultruded composite materials according to claim 1, characterized in that, The adjacent twisted fiber bundles (1) of the closed loop (101) are in direct contact; Alternatively, untwisted fiber bundles (2) may be filled between adjacent twisted fiber bundles (1) of the closed loop (101).

4. The method for controlling the performance of pultruded composite materials according to claim 1, characterized in that, The multiple twisted fiber bundles (1) are distributed in a single layer on the outer layer of the fiber bundle stack structure (100), and the twist directions of adjacent twisted fiber bundles (1) are opposite. Alternatively, multiple twisted fiber bundles (1) are distributed in multiple layers on the outer layer of the fiber bundle stack structure (100), with the twisted fiber bundles (1) in the same layer having the same twist direction and the twisted fiber bundles (1) in adjacent layers having opposite twist directions.

5. The method for controlling the performance of pultruded composite materials according to claim 4, characterized in that, When the minimum wall thickness of the fiber bundle stack structure (100) is less than 10 mm, the number of layers of the multiple twisted fiber bundles (1) distributed on the outer layer of the fiber bundle stack structure (100) does not exceed 2. When the minimum wall thickness of the fiber bundle stack structure (100) is 10mm-30mm, the number of layers of the multiple twisted fiber bundles (1) distributed on the outer layer of the fiber bundle stack structure (100) does not exceed 3. When the minimum wall thickness of the fiber bundle stack structure (100) is 30mm-50mm, the number of layers of the multiple twisted fiber bundles (1) distributed on the outer layer of the fiber bundle stack structure (100) does not exceed 4.

6. The method for controlling the performance of pultruded composite materials according to claim 1, characterized in that, The twist angle of the twisted fiber bundle (1) is 5°-30°.

7. A pultruded composite material obtained based on the performance control method of pultruded composite materials according to any one of claims 1 to 6, characterized in that, include: The closed loop (101) is formed by multiple twisted fiber bundles (1), wherein the twisted fiber bundles (1) are unidirectional twisted fiber bundles; The aggregate (102) is formed by multiple strands of untwisted fiber bundles (2); The stack (102) fills the internal space of the closed ring (101).

8. The pultruded composite material according to claim 7, characterized in that, Also includes: The surface layer (103) is formed by multiple strands of untwisted fiber bundles (2), which covers the outer surface of the closed ring layer (101) and fills the uneven texture of the outer surface of the closed ring layer (101).

9. The pultruded composite material according to claim 7, characterized in that, The adjacent twisted fiber bundles (1) of the closed loop (101) are in direct contact or filled with untwisted fiber bundles (2).

10. The pultruded composite material according to claim 7, characterized in that, The closed loop (101) includes a layer of twisted fiber bundles, and the twist directions of adjacent twisted fiber bundles (1) are opposite. Alternatively, the closed loop layer (101) may include multiple layers of twisted fiber bundles, wherein the twisted fiber bundles (1) in the same layer are twisted in the same direction, and the twisted fiber bundles (1) in adjacent layers are twisted in opposite directions.

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