Carbon fiber and silk fiber gradient hybrid composite material and preparation method thereof

Abstract

The invention relates to the technical field of composite materials, in particular to a preparation method of a carbon fiber and silk fiber gradient hybrid composite material and a hybrid composite material obtained according to the method, and the method comprises the following steps: (1) weaving a silk fiber fabric; (2) weaving a carbon fiber fabric; (3) designing a hybrid structure of the hybrid composite material; and (4) preparing the carbon fiber and silk fiber gradient hybrid composite material. By designing the hybrid structure, the impact resistance of the composite material plate can be effectively improved, the sandwich hybrid structure is relatively concentrated in impact stress and small in damage area, and the interlayer hybrid structure is prone to layering damage; the sandwich hybrid composite material prepared from the three-dimensional through-angle interlocking fabric woven by the silk fibers is superior to a plain sandwich hybrid composite material in flexural rigidity, after-impact deformation quantity and energy absorption ratio, so that the sandwich hybrid composite material prepared from the silk fiber three-dimensional through-angle interlocking fabric is higher in damage tolerance when being impacted; the properties such as strength and toughness are most excellent.

Description

Technical Field

[0001] The present invention relates to the field of composite materials, and more specifically, to a method for preparing a carbon fiber silk fiber gradient hybrid composite material. Background Art

[0002] Carbon fiber composite materials are widely used in high-tech fields such as aerospace, ocean-going ships, rail transit, and new energy vehicles due to their properties such as light weight, high strength, high impact damage tolerance, and chemical corrosion resistance. In actual engineering applications, carbon fiber composite components are vulnerable to various external threats such as foreign object impact and cyclic loading. The linear elastic mechanical behavior and brittle fracture failure characteristics are extremely likely to trigger catastrophic collapse accidents, causing significant economic losses and casualties. Therefore, increasing the toughness of carbon fiber composite materials to obtain high-strength and high-toughness composite materials has become the focus of materials science researchers. One effective method is to design hybrid composite materials, mixing brittle carbon fibers with high-toughness polymer fibers, etc., to prepare composite materials with excellent performance and both high strength and high toughness. With the continuous improvement of environmental protection, green, and biodegradable requirements, biodegradable hybrid composite materials have become a research hotspot for scientific researchers and engineers. Silk fiber, as a natural long filament that can be directly used for textile in nature, has a long history and unique characteristics. This fiber exhibits excellent performance in terms of strength, ductility, and energy absorption. Particularly crucial is that the amino acid composition of sericin is rich in amino and carboxyl groups, which can form strong chemical bonds with epoxy resin or its curing agent, thereby enhancing the adhesion strength between the fiber and the epoxy resin matrix; moreover, silk has the advantage of natural biodegradability and performs well in terms of impact resistance. These properties enable silk fibers to be used to prepare fiber-reinforced composite materials. The high toughness and elastic energy absorption ability of the prepared silk composite materials are their characteristics, and people are increasingly interested in natural silk as an alternative reinforcement material for engineering composite materials.

[0003] However, when preparing composite materials by hybridizing carbon fibers and silk fibers, only the two fiber materials or fabrics are simply mixed, only focusing on the influence of the hybrid ratio on the performance of the composite material, lacking the optimization design of the fabric structures of the two, especially the design of the silk fiber fabric structure during hybridization, which is limited to unidirectional cloth and woven plain fabric. The specific problems are as follows:

[0004] (1) The hybrid structure is the key factor determining the mechanical properties of hybrid fiber composite materials. Common hybrid methods can be roughly divided into three categories: in-plane hybridization, interlaminar hybridization, and sandwich hybridization. The most studied hybrid structure currently is interlaminar hybridization. When designing a carbon fiber silk fiber gradient hybrid composite material, the fabric structures of the two fiber materials or those prepared therefrom are single, severely restricting the performance of each, and lacking the analysis of the influence of different fabric structures on the performance of the composite material;

[0005] (2) The properties of hybrid composites are significantly affected by the proportion of hybrid fibers. The influence of the hybrid ratio on the composites generally needs to be comprehensively considered from aspects such as the mechanical properties, heat resistance, and cost of different types of fibers according to specific requirements. Existing studies have found that increasing the proportion of carbon fibers enhances the tensile strength and flexural modulus of the composites, while increasing the proportion of silk fibers improves the toughness, impact strength, and energy absorption rate of the composites. However, the change in the fabric structure in the hybrid fibers will conversely affect the hybrid ratio, and the coupling relationship between the two has not been concerned. Summary of the Invention

[0006] In order to better solve the above problems, the object of the present invention is to start from improving the brittleness of carbon fibers, and use natural silk fibers with high toughness and degradability and carbon fibers with high stiffness and strength for hybridization, so as to provide a preparation method for a high-strength and high-toughness carbon fiber-silk fiber gradient hybrid composite, and obtain a hybrid composite with excellent properties and gradient structure changes.

[0007] In the first aspect, the present invention provides a preparation method for a carbon fiber-silk fiber gradient hybrid composite, and the method includes the following steps:

[0008] Step S1: Weave a silk fiber fabric;

[0009] Step S2: Weave a carbon fiber fabric;

[0010] Step S3: Design the gradient hybrid structure of the hybrid composite;

[0011] Step S4: Prepare the carbon fiber-silk fiber gradient hybrid composite.

[0012] As a more preferred technical solution of the present invention, the silk fiber fabric in the step S1 is a three-dimensional structure, including three-dimensional woven fabric, three-dimensional knitted fabric, and three-dimensional braided fabric.

[0013] As a more preferred technical solution of the present invention, the carbon fiber fabric in the step S2 is a one-dimensional structure or a two-dimensional structure, and the dimensional structure of the carbon fiber fabric is smaller than that of the silk fiber fabric, and the thickness of the silk fiber fabric is 2-3 times that of the carbon fiber fabric.

[0014] As a more preferred technical solution of the present invention, the gradient hybrid structure of the hybrid composite in the step S3 is interlayer hybridization or sandwich hybridization, and the outermost layer of the hybrid composite is a carbon fiber fabric.

[0015] As a more preferred technical solution of the present invention, the fiber volume content of the hybrid composite in the step S3 is 45%-65%, and the hybrid ratio of the silk fiber fabric is 40%-60%.

[0016] As a more preferred technical solution of the present invention, the method for hybridizing the composite material in step S4 is compression molding, resin transfer molding or autoclave molding, and the resin transfer molding method uses vacuum assisted resin transfer molding technology.

[0017] As a more preferred technical solution of the present invention, the silk fiber fabric in the hybrid composite material in step S4 is a three-dimensional woven angle interlock fabric, and the carbon fiber fabric is a two-dimensional plain weave fabric.

[0018] As a more preferred technical solution of the present invention, the silk fiber fabric in step S4 is a four-layer three-dimensional woven through angle interlock fabric, the warp density of the fabric is 1.4 threads / cm, the weft density is 1.3 threads / cm, and the gram weight per square meter is 766 g / m2. The warp density of the carbon fiber fabric is 2.4 threads / cm, the weft density is 2.4 threads / cm, and the gram weight per square meter is 480 g / m2. The thickness of the silk fiber fabric is 2.6 times that of the carbon fiber fabric.

[0019] As a more preferred technical solution of the present invention, the silk fiber fabric in step S4 is a four-layer three-dimensional layer-by-layer angle interlock fabric, the warp density of the fabric is 1.4 threads / cm, the weft density is 2.0 threads / cm, and the gram weight per square meter is 899 g / m2. The warp density of the carbon fiber fabric is 2.4 threads / cm, the weft density is 2.4 threads / cm, and the gram weight per square meter is 480 g / m2. The thickness of the silk fiber fabric is 2.6 times that of the carbon fiber fabric.

[0020] In a second aspect, the present application provides a carbon fiber silk fiber gradient hybrid composite material prepared by the preparation method according to any one of the above.

[0021] Compared with the carbon fiber silk fiber gradient hybrid composite material in the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) Compared with the traditional carbon fiber silk fiber composite material with a single fabric structure hybridization, the present invention can effectively improve the impact resistance of the composite material board by designing a gradient hybridization structure. Among them, the impact stress of the sandwich hybridization structure is relatively concentrated, the damage area is small, and the interlayer hybridization structure is prone to delamination damage.

[0023] (2) The present invention first takes the plain weave hybrid composite material as the research object and finds that the sandwich hybrid and the interlayer hybrid composite materials are close in flexural stiffness, but the former is better in absorbing impact energy. Therefore, the sandwich hybrid composite material is particularly outstanding in terms of impact resistance, and finally the sandwich hybrid structure with the best performance is selected.

[0024] (3) In the present invention, the sandwich hybrid composite material prepared from the three-dimensional through-angle interlock fabric woven with silk fibers and the sandwich hybrid composite material prepared from the plain weave silk fabric absorb the most energy during the impact process. Since the energy absorption rate, flexural rigidity, and deformation amount after impact of the three-dimensional through-angle hybrid composite material are all superior to those of the plain weave sandwich hybrid composite material, it shows that the sandwich hybrid composite material prepared from the three-dimensional through-angle interlock fabric woven with silk fibers has a higher damage tolerance, and more excellent properties such as strength and toughness when being impacted. Description of the Drawings

[0025] Figure 1 It is a flowchart of the preparation method of the carbon fiber and silk fiber gradient hybrid composite material of the present application;

[0026] Figure 2 It is the 20J impact energy-time curve of the carbon fiber and silk fiber gradient hybrid composite material of the present application;

[0027] Figure 3 It is the displacement-time curve of the carbon fiber and silk fiber gradient hybrid composite material of the present application under 20J impact energy;

[0028] Figure 4 It is the load-time curve of the carbon fiber and silk fiber gradient hybrid composite material of the present application under 20J impact energy;

[0029] Figure 5 It is the comparison of the energy absorption of the carbon fiber and silk fiber gradient hybrid composite material of the present application under 20J impact energy;

[0030] Figure 6 It is the comparison of the maximum load values of the carbon fiber and silk fiber gradient hybrid composite material of the present application under 20J energy impact;

[0031] Figure 7 It is the comparison of the flexural rigidity values of the carbon fiber and silk fiber gradient hybrid composite material of the present application under 20J energy impact;

[0032] Figure 8 It is the comparison of the specimen morphologies of the carbon fiber and silk fiber gradient hybrid composite material of the present application after 20J energy impact;

[0033] Figure 9 It is the comparison of the impact load-time curves of the three silk fabric composite materials under 10J impact energy;

[0034] Figure 10 It is the comparison of the energy-time curves of the three silk fabric composite materials under 10J impact energy;

[0035] Figure 11 It is the comparison of the displacement-time curves of the three silk fabric composite materials under 10J impact energy. Detailed Embodiments

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0037] In this text, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of simplicity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0038] In this text, unless otherwise specified, terms such as "comprising", "including", "containing", "having" or similar terms cover the meanings of "consisting of" and "consisting essentially of". For example, "A comprises a" covers the meanings of "A comprises a and others" and "A consists only of a".

[0039] In this text, for the sake of brevity of description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as within the scope described in this specification.

[0040] The present invention provides a method for preparing a carbon fiber silk fiber gradient hybrid composite material, as Figure 1 shown, the method comprising the following steps:

[0041] Step S1: Weave a silk fiber fabric.

[0042] Specifically, the silk fiber fabric can be a three-dimensional structure. By utilizing the thickness advantage of the silk fiber fabric, while exerting the high toughness of the silk fiber, its flexural modulus can be increased, thereby increasing the overall flexural modulus of the hybrid composite material.

[0043] Step S2: Weave a carbon fiber fabric.

[0044] Specifically, the carbon fiber fabric can be a one-dimensional structure or a two-dimensional structure, and the dimensional structure of the carbon fiber fabric is smaller than that of the silk fabric. The thickness of the silk fabric is 2-3 times that of the carbon fiber fabric. Such a design can give full play to the high strength and high modulus of the carbon fiber by reducing the thickness of the carbon fiber fabric and prevent damage to the mechanical properties. Because the thicker the carbon fiber fabric, the more buckled the carbon fibers are in the fabric structure, and the more in-plane mechanical properties are lost. Studies have shown that when a higher tensile stress is applied, due to the straightening of the inelastic carbon fiber bundles and the cracking around the most severely curled in-plane carbon fiber bundles, the elastic modulus is reduced by 20-30%; moreover, the more severe the wear during the weaving process, the more damage to the mechanical properties. Studies have shown that during most stages of the three-dimensional woven fabric weaving process, the yarns are damaged due to wear and breakage caused by sliding on the loom machinery, and the wear damage causes the tensile strength of the yarns to be reduced by 30%.

[0045] Step S3: Design the gradient hybrid structure of the hybrid composite material.

[0046] Specifically, the hybrid structure of the hybrid composite material can be interlayer hybridization or sandwich hybridization, and the outermost layer of the hybrid composite material is preferably a carbon fiber fabric.

[0047] Step S4: Prepare the carbon fiber and silk fiber gradient hybrid composite material.

[0048] Specifically, the method for preparing the carbon fiber and silk fiber gradient hybrid composite material can be the compression molding method, the resin transfer molding method or the autoclave molding method, and the resin transfer molding method preferably uses the vacuum assisted resin transfer molding technology.

[0049] Of course, the present invention provides a carbon fiber and silk fiber gradient hybrid composite material, which is prepared according to the above preparation method.

[0050] Compared with the traditional carbon fiber and silk fiber composite material with a single fabric structure hybridization, the present invention can effectively improve the impact resistance of the composite material board by designing a gradient hybrid structure. Among them, the impact stress of the sandwich hybrid structure is relatively concentrated and the damage area is small, while the interlayer hybrid structure is prone to delamination damage.

[0051] The following further elaborates the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0052] Conventional instrumentation and equipment in the art are used in the following examples. For the experimental methods without specific conditions noted in the following examples, they are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Various raw materials are used in the following examples. Unless otherwise stated, commercially available products with conventional specifications in the art are used.

[0053] The ply design of the carbon fiber silk fiber gradient hybrid composite provided by this application is shown in Table 1:

[0054] Table 1 Ply Design of High-Strength and High-Toughness Carbon Fiber Silk Fiber Gradient Hybrid Composite

[0055]

[0056]

[0057] Among them, C - carbon fiber plain weave fabric; S - silk plain weave fabric; LA - layer - angle - interlocked silk fabric; TA - through - angle - interlocked silk fabric.

[0058] Example 1

[0059] The present invention provides a method for preparing a high - strength and high - toughness carbon fiber silk fiber gradient hybrid composite, obtaining a hybrid composite with excellent performance and gradient structural changes. The method includes:

[0060] (1) Weave a silk fiber fabric. The silk fiber used is degummed silk with a fineness of 72.37 tex and a breaking strength of 34.35 cN / tex. The silk fiber fabric is a four - layer three - dimensional through - angle - interlocked fabric (TA). The warp density of the four - layer through - angle - interlocked fabric is 1.4 roots / cm, the weft density is 1.3 roots / cm, and the gram weight per square meter is 766 g / m 2 , and the thickness of the four - layer three - dimensional through - angle - interlocked fabric is 1.45 mm;

[0061] (2) Weave a carbon fiber fabric. The carbon fiber has a fineness of 12 k and a strength of T700S. The carbon fiber fabric is a plain weave fabric. The warp density of the plain weave fabric is 2.4 roots / cm, the weft density is 2.4 roots / cm, and the gram weight per square meter is 480 g / m 2 , and the thickness of the plain weave fabric is 0.56 mm;

[0062] (3) Design the hybrid structure of the hybrid composite. The hybrid structure of the hybrid composite is a sandwich hybrid (C2TA2C2), and the outermost layer of the hybrid composite is preferably two layers of carbon fiber plain weave fabric. The fiber volume content of the hybrid composite is 54%, and the hybrid ratio of the silk fiber fabric is 49%;

[0063] (4) Prepare a carbon fiber silk fiber gradient hybrid composite material, and the method for preparing the carbon fiber silk fiber gradient hybrid composite material is a vacuum-assisted resin transfer molding technology.

[0064] Perform a low-velocity drop weight impact test on the above carbon fiber silk fiber gradient hybrid composite material plate (C2TA2C2) with an impact energy of 20 J. It can be seen that among all the hybrid composite material plates, the bending stiffness of this hybrid composite material plate is the largest, as Figure 7 shown.

[0065] The displacement and deformation generated after the impact are the smallest, as Figure 3 shown in; the maximum load of the impact (see Figure 6 ) and the energy absorption (see Figure 5 ) are second only to C2S4C2 and (CS)4. Combining the charts and Figure 8 it can be seen that none of the carbon fiber silk fiber gradient hybrid composite material plates are penetrated, and severe delamination appears on the back of the interlayer hybrid composite material plate C2S4C2. To obtain a hybrid composite material with large bending stiffness, good energy absorption, and small deformation ability, considering comprehensively, the carbon fiber silk fiber gradient hybrid composite material plate with a ply structure of C2TA2C2 has the best performance.

[0066] Example 2

[0067] The present invention provides a method for preparing a high-strength and high-toughness carbon fiber silk fiber gradient hybrid composite material, and obtains a hybrid composite material with excellent performance and a gradient structure change. The method includes:

[0068] (1) Weave a silk fiber fabric. The silk fiber is degummed silk with a fineness of 72.37 tex and a breaking strength of 34.35 cN / tex. The silk fiber fabric is a four-layer three-dimensional layer-to-layer angle interlock fabric (LA). The warp density of the four-layer three-dimensional through angle interlock fabric is 1.4 threads / cm, the weft density is 2.0 threads / cm, the grammage per square meter is 899 g / m2, and the thickness of the four-layer three-dimensional through angle interlock fabric is 1.46 mm;

[0069] (2) Weave a carbon fiber fabric. The carbon fiber has a fineness of 12k and a strength of T700S. The carbon fiber fabric is a plain weave fabric. The warp density of the plain weave fabric is 2.4 threads / cm, the weft density is 2.4 threads / cm, the fabric thickness is 0.56 mm, and the grammage per square meter is 480 g / m 2 ;

[0070] (3) Design the hybrid structure of the hybrid composite material. The hybrid structure of the hybrid composite material is a sandwich hybrid (C2LA2C2), and the outermost layer of the hybrid composite material is preferably two layers of carbon fiber plain weave fabrics. The fiber volume content of the hybrid composite material is 59%, and the hybrid ratio of the silk fiber fabric is 53%.

[0071] (4) Prepare a carbon fiber silk fiber gradient hybrid composite material. The method for preparing the carbon fiber silk fiber gradient hybrid composite material is the vacuum assisted resin transfer molding technology.

[0072] Perform a low velocity drop weight impact test on the above carbon fiber silk fiber gradient hybrid composite material plate (C2LA2C2) with an impact energy of 20 J. It can be seen that among all the hybrid composite material plates, the bending stiffness of this hybrid composite material plate is only less than that of the hybrid composite material plate (C2TA2C2) (as Figure 7 shown), and the displacement and deformation generated after impact are only less than those of the hybrid composite material plate (C2TA2C2) (as Figure 3 shown). The maximum load during impact (as Figure 6 shown) and energy absorption (as Figure 5 shown) are second only to C2S4C2 and C2TA2C2. Combining Table 1 and Figure 8 it can be seen that none of the carbon fiber silk fiber gradient hybrid composite material plates are penetrated, and severe delamination appears on the back of the interlayer hybrid composite material plate C2S4C2 after impact. To obtain a hybrid composite material with high bending stiffness, good energy absorption and small deformation ability, considering comprehensively, the performance of the carbon fiber silk fiber gradient hybrid composite material plate with a ply structure of C2LA2C2 is the second choice.

[0073] Comparative Example 1

[0074] The present invention provides a method for preparing a high strength and high toughness carbon fiber silk fiber gradient hybrid composite material to obtain a hybrid composite material. The method includes:

[0075] (1) Weave a silk fiber fabric. The silk fiber used is degummed silk with a fineness of 72.37 tex and a breaking strength of 34.35 cN / tex. The silk fiber fabric is a two-dimensional plain weave fabric. The warp density of the plain weave fabric is 10 roots / cm, the weft density is 14 roots / cm, and the grammage per square meter is 547 g / m 2 , and the thickness of the plain weave fabric is 0.55 mm;

[0076] (2) Weave a carbon fiber fabric. The carbon fiber has a fineness of 12 k and a strength of T700S. The carbon fiber fabric is a two-dimensional plain weave fabric. The warp density of the plain weave fabric is 2.4 roots / cm, the weft density is 2.4 roots / cm, the fabric thickness is 0.56 mm, and the grammage per square meter is 480 g / m 2 ;

[0077] (3) Design the hybrid structure of the hybrid composite material. The hybrid structure of the hybrid composite material is interlayer hybridization ((CS)4), and the outermost layer of the hybrid composite material is preferably two layers of plain weave carbon fiber fabric. The fiber volume content of the hybrid composite material is 60%, and the hybridization ratio of the silk fiber fabric is 44%.

[0078] (4) Prepare the carbon fiber silk fiber gradient hybrid composite material. The method for preparing the carbon fiber silk fiber gradient hybrid composite material is the vacuum assisted resin transfer molding technology.

[0079] Perform a low velocity drop weight impact test on the above carbon fiber silk fiber gradient hybrid composite material plate ((CS)4) with an impact energy of 20 J. It can be seen that among all the hybrid composite material plates, the flexural stiffness of ((CS)4) is less than that of the sandwich hybrid composite material plate with gradient structure change.

[0080] Comparative Example 2

[0081] The present invention provides a method for preparing a high strength and high toughness carbon fiber silk fiber gradient hybrid composite material to obtain a hybrid composite material. The method includes:

[0082] (1) Weave the silk fiber fabric. The silk fiber used is degummed silk with a fineness of 72.37 tex and a breaking strength of 34.35 cN / tex. The silk fiber fabric is a two-dimensional plain weave fabric. The warp density of the plain weave fabric is 10 roots / cm, the weft density is 14 roots / cm, and the grammage per square meter is 547 g / m 2 , and the thickness of the plain weave fabric is 0.55 mm;

[0083] (2) Weave the carbon fiber fabric. The carbon fiber has a fineness of 12 k and a strength of T700S. The carbon fiber fabric is a two-dimensional plain weave fabric. The warp density of the plain weave fabric is 2.4 roots / cm, the weft density is 2.4 roots / cm, the fabric thickness is 0.56 mm, and the grammage per square meter is 480 g / m 2 ;

[0084] (3) Design the hybrid structure of the hybrid composite material. The hybrid structure of the hybrid composite material is sandwich hybridization (C2S4C2), and the outermost layer of the hybrid composite material is preferably two layers of plain weave carbon fiber fabric. The fiber volume content of the hybrid composite material is 60%, and the hybridization ratio of the silk fiber fabric is 44%.

[0085] (4) Prepare the carbon fiber silk fiber gradient hybrid composite material. The method for preparing the carbon fiber silk fiber gradient hybrid composite material is the vacuum assisted resin transfer molding technology.

[0086] The above carbon fiber and silk fiber gradient hybrid composite plate (C2S4C2) was subjected to a low-velocity impact test with an impact energy of 20 J. It can be seen that among all the hybrid composite plates, the bending stiffness of C2S4C2 is less than that of the sandwich hybrid composite plate with a gradient structure change.

[0087] To further illustrate the excellent performance of the sandwich hybrid composite plate with a gradient structure change, low-velocity impact experiments were carried out on three different silk fabrics: two-dimensional plain weave fabric, four-layer three-dimensional layer-by-layer angle interlock fabric (LA), and four-layer three-dimensional through angle interlock fabric (TA). The results show that the failure mechanisms of the three silk fabric composites are significantly different. As Figures 9 - 11 shown, it was found that the maximum impact load of the composite material (TA1) prepared with the four-layer three-dimensional through angle interlock silk fabric was significantly higher than that of the composite material (LA1) prepared with the four-layer three-dimensional layer-by-layer angle interlock fabric and the plain weave fabric composite material (S3) ( Figure 9 ), indicating that the composite material can withstand a greater load without immediate failure at the initial stage of impact. At the same time, in terms of the comparison of the impact action time, the composite material (TA1) showed a lower value, and the maximum displacement of the impact deformation was also the smallest, indicating that its deformation after impact was the smallest ( Figure 11 ); the impact energy absorption rates of the composite materials prepared with the three silk fabrics were almost the same ( Figure 10 ). The composite material (TA1) has the highest impact load and the smallest deformation. Therefore, the gradient hybrid composite material prepared with the four-layer three-dimensional through angle interlock fabric woven with silk fibers as the core layer and the carbon fiber plain weave fabric as the outermost layer has the best impact resistance; at the same time, the four-layer three-dimensional layer-by-layer angle interlock fabric woven with silk fibers as the core layer and the carbon fiber plain weave fabric as the outermost layer is the second choice for the gradient hybrid composite material.

[0088] The present application provides a carbon fiber silk fiber gradient hybrid composite material and a preparation method thereof. Compared with the traditional carbon fiber silk fiber composite material with a single fabric structure hybrid, the impact resistance of the composite material board can be effectively improved by designing a gradient hybrid structure. Among them, the impact stress of the sandwich hybrid structure is relatively concentrated and the damage area is small, while the interlayer hybrid structure is prone to delamination damage. Taking the plain weave hybrid composite material as the research object, it is found that the sandwich hybrid composite material and the interlayer hybrid composite material are close in flexural stiffness, but the former is better in absorbing impact energy. Therefore, the sandwich hybrid composite material is particularly outstanding in terms of impact resistance, and finally the sandwich hybrid structure with the best performance is selected. The sandwich hybrid composite material prepared by using the three-dimensional through-angle interlock fabric woven with silk fiber and the sandwich hybrid composite material prepared by using the plain weave fabric of silk fiber absorb the most energy during the impact process. Since the three-dimensional through-angle interlock hybrid composite material is superior to the plain weave sandwich hybrid composite material in terms of energy absorption rate, flexural stiffness, and deformation after impact, it shows that the sandwich hybrid composite material prepared by using the three-dimensional through-angle interlock fabric woven with silk fiber has a higher damage tolerance and more excellent properties such as strength and toughness when being impacted.

[0089] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A preparation method of a carbon fiber and silk fiber gradient hybrid composite material, characterized in that, It includes the following steps: Step S1: Weave a silk fiber fabric; Step S2: Weave a carbon fiber fabric; Step S3: Design the gradient hybrid structure of the hybrid composite material; Step S4: Prepare the carbon fiber silk fiber gradient hybrid composite material.

2. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 1, wherein In the step S1, the silk fiber fabric is a three-dimensional structure, including a three-dimensional woven fabric, a three-dimensional knitted fabric, and a three-dimensional braided fabric.

3. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 1 or 2, characterized in that, In the step S2, the carbon fiber fabric is a one-dimensional structure or a two-dimensional structure, and the dimensional structure of the carbon fiber fabric is smaller than that of the silk fiber fabric. The thickness of the silk fiber fabric is 2-3 times that of the carbon fiber fabric.

4. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 3, characterized in that The gradient hybrid structure of the hybrid composite material in the step S3 is interlayer hybridization or sandwich hybridization, and the outermost layer of the hybrid composite material is a carbon fiber fabric.

5. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 3, characterized in that, The fiber volume content of the hybrid composite material in the step S3 is 45%-65%, and the hybridization ratio of the silk fiber fabric is 40%-60%.

6. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 5, characterized in that, The method for the hybrid composite material in the step S4 is compression molding, resin transfer molding, or autoclave molding. Among them, the resin transfer molding method uses vacuum-assisted resin transfer molding technology.

7. The preparation method of a carbon fiber silk fiber gradient hybrid composite material according to claim 6, characterized in that, In the hybrid composite material in the step S4, the silk fiber fabric is a three-dimensional woven angle-interlock fabric, and the carbon fiber fabric is a two-dimensional plain fabric.

8. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 7, characterized in that The silk fiber fabric in step S4 is a four-layer three-dimensional woven through-angle interlock fabric. The warp density of the fabric is 1.4 threads / cm, the weft density is 1.3 threads / cm, and the grammage per square meter is 766 g / m 2 , the warp density of the carbon fiber fabric is 2.4 threads / cm, the weft density is 2.4 threads / cm, and the grammage per square meter is 480 g / m 2 , and the thickness of the silk fiber fabric is 2.6 times that of the carbon fiber fabric.

9. The preparation method of a carbon fiber and silk fiber gradient hybrid composite material according to claim 7, characterized in that, The silk fiber fabric in the step S4 is a four-layer three-dimensional layer-by-layer angle interlock fabric, the warp density of the fabric is 1.4 threads / cm, the weft density is 2.0 threads / cm, and the grammage per square meter is 899 g / m 2 , the warp density of the carbon fiber fabric is 2.4 threads / cm, the weft density is 2.4 threads / cm, and the grammage per square meter is 480 g / m 2 , and the thickness of the silk fiber fabric is 2.6 times that of the carbon fiber fabric.

10. A carbon fiber and silk fiber gradient hybrid composite material, characterized in that: It is obtained by the preparation method according to any one of claims 1-9.

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