A method for preparing wave-transmitting fiber for reducing curing deformation of co-cured composite materials

Abstract

The present invention relates to the technical field of composite material forming, and in particular to a method for preparing a wave-transmitting fiber that reduces the curing deformation of a co-cured composite material, comprising the following steps: detecting the thermal expansion coefficient of the matrix fiber material therein; preliminarily determining the linear density, twisting form and weaving pattern of the wave-transmitting fiber material, and thereby obtaining a wave-transmitting fiber fabric, and then detecting its thermal expansion coefficient; matching the thermal expansion coefficient with the thermal expansion coefficient by changing the corresponding linear density, twisting form and / or weaving pattern; preparing a wave-absorbing prepreg, and co-curing the wave-absorbing prepreg with the matrix prepreg into a composite panel. The technical scheme controls the thermal expansion coefficient of aramid fibers by regulating the linear density, twisting mode and fabric form of the wave-transmitting fiber fabric in the wave-absorbing prepreg, so that it matches the thermal expansion coefficient of the matrix fiber, thereby reducing the overall deformability of the co-cured panel finally prepared.

Description

Technical Field

[0001] The invention relates to the technical field of composite material molding, and in particular to a method for preparing a wave-transmitting fiber capable of reducing the curing deformation of a co-cured composite material. Background Art

[0002] The absorbing prepreg has excellent absorbing performance due to its height / thickness controllability. Compared with stealth coating, it has excellent absorbing performance and process performance, and is very likely to replace stealth coating as a new stealth material. Its characteristic is co-curing with the matrix prepreg, but the resin system and fiber system of the matrix prepreg are different from those of the absorbing prepreg. Therefore, during the co-curing process, the deformation of the panel is greatly increased due to the different thermal expansion coefficients of the absorbing prepreg and the matrix prepreg, which ultimately leads to serious deformation of the parts, affecting subsequent assembly and use.

[0003] Conventional prior art, such as the Chinese patent document with publication number CN115742474A, discloses a low curing deformation absorbing layer plate and its preparation method, which specifically discloses: a low modulus absorbing adhesive film is prepared by compounding a resin matrix, an absorbent, an additive and low modulus small particles; a low modulus glass fiber prepreg is prepared by compounding glass fiber, a resin matrix and low modulus small particles; a carbon fiber prepreg, a low modulus absorbing adhesive film and a low modulus glass fiber prepreg are sequentially laid on the surface of a molding tool, and co-curing molding is performed to obtain a low curing deformation absorbing layer plate. This prior art can significantly reduce the deformation of the absorbing layer plate during molding due to the introduction of low modulus small particles and the use of co-curing molding. The defect of the aforementioned prior art is that the addition of a flexible resin to reduce the deformation of the plate will cause the glass transition temperature of the prepreg to be greatly reduced, thereby reducing the use temperature of the prepreg. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention discloses a method for preparing a wave-transmitting fiber that reduces the curing deformation of a co-cured composite material, which is specifically as follows:

[0005] A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material comprises the following steps: S1, selecting a matrix prepreg and detecting the thermal expansion coefficient of a matrix fiber material in the matrix prepreg . S2, according to the thermal expansion coefficient Preliminarily determine the linear density, twisting form and weaving pattern of the wave-transmitting fiber material. S3, weave the wave-transmitting fiber material of corresponding linear density into a fabric form according to the determined twisting form and weaving pattern to obtain the wave-transmitting fiber fabric. S4, detect the thermal expansion coefficient of the wave-transmitting fiber fabric , and determine the thermal expansion coefficient and thermal expansion coefficient Whether they match; if they match, proceed to step S5; if they do not match, change the linear density and / or twisting form and / or weaving pattern of the wave-transmitting fiber material, and then return to step S3. S5, mix the absorbent with the resin matrix to obtain an absorbing resin. S6, compound the absorbing resin with the fiber fabric to obtain an absorbing prepreg. S7, lay the absorbing prepreg along the aerodynamic surface to a target thickness. S8, lay the matrix prepreg on the laid absorbing prepreg, and then co-cure to form a composite panel of the absorbing prepreg and the matrix prepreg.

[0006] Preferably, in step S2, the wave-transmitting fiber material is one of quartz fiber and aramid fiber, or a mixture of quartz fiber and aramid fiber.

[0007] Preferably, in step S2, the weaving patterns of the wave-transmitting fiber material include plain weave, twill weave and satin weave, and also include a combination of at least two of the plain weave, twill weave and satin weave.

[0008] Preferably, in step S5, the absorbent is one of carbon-based, iron-based, and dielectric-based absorbents, or a composite absorbent of any two or more thereof.

[0009] Preferably, in step S5, the mass fraction of the absorbent to the absorbing resin is 50-90 wt %.

[0010] Preferably, in step S5, the resin matrix is ​​one of epoxy resin, bismaleimide and polyimide, or a composite resin of any two or more thereof.

[0011] Preferably, in step S6, the weight percentage of the absorbing resin in the absorbing prepreg is 80-98 wt %.

[0012] Preferably, in step S7, the target thickness of the absorbing prepreg stacking is 0.2-4 mm.

[0013] Preferably, in step S1, the matrix prepreg is one of carbon fiber prepreg, aramid fiber prepreg and glass fiber prepreg, or a composite prepreg of any two or more thereof.

[0014] Preferably, in step S8, the paving thickness of the matrix prepreg is 0.5-10 mm.

[0015] Beneficial technical effects brought by the present invention:

[0016] The present technical solution discloses a method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material. By testing the thermal expansion coefficient of a matrix fiber material in a matrix prepreg, the linear density, twisting method, and fabric form of the wave-transmitting fiber fabric in the wave-absorbing prepreg are regulated to control the thermal expansion coefficient of the aramid fiber so that it matches the thermal expansion coefficient of the matrix fiber, thereby reducing the overall deformability of the co-cured panel finally prepared, so that the wave-absorbing prepreg co-cured composite material meets the assembly requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the implementation flow chart of this technical solution. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0019] Therefore, the following detailed description of the invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1

[0021] This embodiment discloses a method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material, as a preferred embodiment of the present invention. Figure 1 As shown, the following steps are included:

[0022] S1, select the matrix prepreg and detect the thermal expansion coefficient of the matrix fiber material in the matrix prepreg .

[0023] S2, according to the thermal expansion coefficient The linear density, twisting form and weaving pattern of the wave-transmitting fiber material were preliminarily determined.

[0024] S3, weaving the wave-transmitting fiber material of corresponding linear density into a fabric form according to the determined twisting form and weaving pattern to obtain the wave-transmitting fiber fabric.

[0025] S4, testing the thermal expansion coefficient of wave-transmitting fiber fabrics , and determine the thermal expansion coefficient and thermal expansion coefficient If they match, then go to step S5; if they do not match, then change the linear density and / or twisting form and / or weaving pattern of the wave-transmitting fiber material and then go back to step S3. and thermal expansion coefficient The difference is within the allowable range, which determines the deformation of the final product.

[0026] S5, mixing the absorbent with the resin matrix to obtain a microwave absorbing resin.

[0027] S6, compounding the microwave absorbing resin with the fiber fabric to obtain a microwave absorbing prepreg.

[0028] S7, laying the radar absorbing prepreg along the aerodynamic surface to a target thickness.

[0029] S8, laying the matrix prepreg on the laid-up absorbing prepreg, and then co-curing to form a composite panel of the absorbing prepreg and the matrix prepreg.

[0030] Example 2

[0031] This embodiment discloses a method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Example 1, in step S2, the wave-transmitting fiber material is one of quartz fiber and aramid fiber, or a mixture of quartz fiber and aramid fiber, and the linear density of the wave-transmitting fiber material ranges from 200 to 6000 dtex.

[0032] Example 3

[0033] This embodiment discloses a method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Embodiment 1 or 2, in step S2, the wave-transmitting fiber material is twisted or untwisted. In addition, the weaving patterns of the wave-transmitting fiber material include plain weave, twill and satin, and also include a combination of at least two of the plain weave, twill and satin patterns.

[0034] Example 4

[0035] This embodiment discloses a method for preparing a wave-transmitting fiber that reduces the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Embodiment 1, 2 or 3, in step S5, the absorbent is one of carbon, iron and dielectric systems, or a composite absorbent of any two or more thereof. The absorbent accounts for 50-90 wt% of the mass fraction of the wave-absorbing resin, and the mutual matching of different types of absorbents is mainly used to improve the wave-absorbing performance of the wave-absorbing prepreg. Furthermore, in step S6, the wave-absorbing resin accounts for 80-98 wt% of the mass fraction of the wave-absorbing prepreg.

[0036] Example 5

[0037] This embodiment discloses a method for preparing a wave-transmitting fiber that reduces the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Embodiment 1, 2, 3 or 4, in step S5, the resin matrix is ​​one of epoxy resin, bismaleimide resin and polyimide, or a composite resin of any two or more thereof. The selection of the resin matrix takes into account the use temperature and the performance of the preparation process of the wave-absorbing prepreg.

[0038] Example 6

[0039] This embodiment discloses a method for preparing a wave-transmitting fiber that reduces the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Embodiments 1, 2, 3, 4 or 5, in step S7, the stacking thickness of the wave-absorbing prepreg is determined according to the type of absorbent used and the absorbent content. Specifically, the target thickness of the wave-absorbing prepreg stacking is 0.2-4 mm. By adjusting the used thickness (target thickness) of the wave-absorbing prepreg, the co-cured panel can absorb electromagnetic waves within the required band and have the best wave-absorbing performance.

[0040] Example 7

[0041] This embodiment discloses a method for preparing a wave-transmitting fiber that reduces the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Embodiments 1, 2, 3, 4, 5 or 6, in step S8, the matrix prepreg is one of carbon fiber prepreg, aramid fiber prepreg and glass fiber prepreg, or a composite prepreg of any two or more thereof. Further, the paving thickness of the matrix prepreg is 0.5 to 10 mm. The thickness ratio of the matrix prepreg can be increased by adjusting the thickness ratio of the matrix prepreg to the wave-absorbing prepreg, and the deformation of the co-cured panel can be further reduced.

[0042] Example 8

[0043] This embodiment discloses a method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material. As a preferred embodiment of the present invention, based on Embodiments 1, 2, 3, 4, 5, 6 or 7, taking a matrix prepreg whose matrix fiber material is carbon fiber as an example, the thermal expansion coefficient thereof is measured. Based on this, the surface density, twisting form and weaving pattern were used as variables, and the wave-transmitting fibers were processed by changing the surface density, twisting form or weaving pattern.

[0044] (I) Aramid fibers with a linear density of 3000 dtex were selected and woven into wave-transmitting fiber fabrics using a twisting + twill weaving process. The thermal expansion coefficient of the wave-transmitting fiber fabrics was measured. . Carbonyl iron was added to high-temperature epoxy resin at a content of 70% to obtain an absorbing resin, and then the absorbing resin was prepared into an absorbing film, and the absorbing film was compounded with a wave-transmitting fiber fabric to obtain an absorbing prepreg. 1.2 mm absorbing prepreg was stacked along the aerodynamic surface, 2.5 mm carbon fiber prepreg was laid on the absorbing prepreg, and the 300 mm*300 mm co-cured board was obtained by bagging and packaging. The absorbing prepreg of the co-cured board was turned down on the table, and the maximum distance between the absorbing prepreg and the table was measured to be 7.2 mm.

[0045] (ii) Aramid fibers with a linear density of 3000 dtex were selected and woven into wave-transmitting fiber fabrics using a non-twisting + twill weaving process. The thermal expansion coefficient of the wave-transmitting fiber fabrics was measured. . Carbonyl iron was added to high-temperature epoxy resin at a content of 70% to obtain an absorbing resin, and then the absorbing resin was prepared into an absorbing adhesive film, and the absorbing adhesive film was compounded with a wave-transmitting fiber fabric to obtain an absorbing prepreg. 1.2 mm absorbing prepreg was laid along the aerodynamic surface, 2.5 mm carbon fiber prepreg was laid on the absorbing prepreg, and the 300 mm*300 mm co-cured board was obtained by bagging and packaging. The absorbing prepreg of the co-cured board was turned down on the table, and the maximum distance between the absorbing prepreg and the table was measured to be 5.6 mm.

[0046] (III) Select aramid fiber with a linear density of 800 dtex, use twisting + twill weaving process to weave the aramid fiber into wave-transmitting fiber fabric, and measure the thermal expansion coefficient of the wave-transmitting fiber fabric . Carbonyl iron was added to high-temperature epoxy resin at a content of 70% to obtain an absorbing resin, and then the absorbing resin was prepared into an absorbing film, and the absorbing film was compounded with a wave-transmitting fiber fabric to obtain an absorbing prepreg. 1.2 mm absorbing prepreg was stacked along the aerodynamic surface, 2.5 mm carbon fiber prepreg was laid on the absorbing prepreg, and the 300 mm*300 mm co-cured board was obtained by bagging and packaging. The absorbing prepreg of the co-cured board was turned down on the table, and the maximum distance between the absorbing prepreg and the table was measured to be 3.8 mm.

[0047] (IV) Select aramid fiber with a linear density of 3000 dtex, use twisting + satin weaving process to weave the aramid fiber into wave-transmitting fiber fabric, and measure the thermal expansion coefficient of the wave-transmitting fiber fabric . Carbonyl iron was added to high-temperature epoxy resin at a content of 70% to obtain an absorbing resin, and then the absorbing resin was prepared into an absorbing film, and the absorbing film was compounded with a wave-transmitting fiber fabric to obtain an absorbing prepreg. 1.2 mm absorbing prepreg was laid along the aerodynamic surface, 2.5 mm carbon fiber prepreg was laid on the absorbing prepreg, and the 300 mm*300 mm co-cured plate was obtained by bagging and packaging. The absorbing prepreg of the co-cured plate was turned down on the table, and the maximum distance between the absorbing prepreg and the table was measured to be 4.4 mm.

[0048] (V) Select aramid fiber with a linear density of 3000 dtex, use twisting + plain weave to weave the aramid fiber into a wave-transmitting fiber fabric, and measure the thermal expansion coefficient of the wave-transmitting fiber fabric . Carbonyl iron was added to high-temperature epoxy resin at a content of 70% to obtain an absorbing resin, and then the absorbing resin was prepared into an absorbing film, and the absorbing film was compounded with a wave-transmitting fiber fabric to obtain an absorbing prepreg. 1.2 mm absorbing prepreg was laid along the aerodynamic surface, and 2.5 mm carbon fiber prepreg was laid on the absorbing prepreg, and the 300 mm*300 mm co-cured plate was obtained by bagging and co-curing. The absorbing prepreg of the co-cured plate was turned down on the table, and the maximum distance between the absorbing prepreg and the table was measured to be 13.6 mm.

[0049] Thus, the following thermal expansion coefficient is obtained: And the list of factors affecting the deformation of co-cured panels:

[0050]

[0051] It can be seen from the above table that, under the condition of linear density as the variable, the smaller the linear density, the greater the thermal expansion coefficient. The larger the thermal expansion coefficient is, the larger the thermal expansion coefficient is. Greater than the thermal expansion coefficient of twisting ; When the weaving pattern is used as the variable, the thermal expansion coefficient of satin >Twill thermal expansion coefficient >Thermal expansion coefficient of plain weave Based on this, the thermal expansion coefficient of the matrix fiber material in the selected matrix prepreg can be By adjusting the above three variables, the thermal expansion coefficient can be controlled. and thermal expansion coefficient Matching, thereby reducing the curing deformation of the wave-transmitting fiber during the co-curing process.

Claims

1. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material, characterized in that: The following steps are involved: S1, select the matrix prepreg and detect the thermal expansion coefficient of the matrix fiber material in the matrix prepreg ; S2, according to the thermal expansion coefficient Preliminarily determine the linear density, twisting form and weaving pattern of the wave-transmitting fiber material; S3, weaving the wave-transmitting fiber material with a corresponding linear density into a fabric form according to the determined twisting form and weaving pattern, so as to obtain the wave-transmitting fiber fabric; S4, testing the thermal expansion coefficient of wave-transmitting fiber fabrics , and determine the thermal expansion coefficient and thermal expansion coefficient Whether they match; if they match, proceed to step S5; if they do not match, change the linear density and / or twisting form and / or weaving pattern of the wave-transmitting fiber material and return to step S3; S5, mixing the absorbent with the resin matrix to obtain a microwave absorbing resin; S6, compounding the microwave absorbing resin with the fiber fabric to obtain a microwave absorbing prepreg; S7, laying the radar absorbing prepreg along the aerodynamic surface to a target thickness; S8, laying the matrix prepreg on the laid-up absorbing prepreg, and then co-curing to form a composite panel of the absorbing prepreg and the matrix prepreg.

2. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S2, the wave-transmitting fiber material is one of quartz fiber and aramid fiber, or a mixture of quartz fiber and aramid fiber.

3. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S2, the weaving patterns of the wave-transmitting fiber material include plain weave, twill weave and satin weave, and also include a combination of at least two of the plain weave, twill weave and satin weave.

4. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S5, the absorbent is one of carbon-based, iron-based, and dielectric-based absorbents, or a composite absorbent of any two or more thereof.

5. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S5, the absorbent accounts for 50-90 wt % of the absorbing resin.

6. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S5, the resin matrix is ​​one of epoxy resin, bismaleimide and polyimide, or a composite resin of any two or more thereof.

7. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In step S6, the absorbing resin accounts for 80-98 wt % of the absorbing prepreg.

8. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S7, the target thickness of the absorbing prepreg is 0.2-4 mm.

9. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S1, the matrix prepreg is one of carbon fiber prepreg, aramid fiber prepreg and glass fiber prepreg, or a composite prepreg of any two or more thereof.

10. A method for preparing a wave-transmitting fiber for reducing the curing deformation of a co-cured composite material as claimed in claim 1, characterized in that: In the step S8, the paving thickness of the matrix prepreg is 0.5-10 mm.

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