Integrated three-dimensional woven honeycomb fabric, composite material of integrated three-dimensional woven honeycomb fabric and preparation method of composite material

Abstract

The invention relates to the technical field of textile materials, and discloses an integrated three-dimensional woven honeycomb fabric, each honeycomb side surface of the woven honeycomb fabric inclined to the warp direction is of a single-layer structure, and two sides parallel to the warp direction are formed by connecting two adjacent overlapped plain weaves. In the integrated three-dimensional woven honeycomb fabric prepared by the invention, the warp yarns and the weft yarns are tightly interwoven into a whole, the integrality is good, and a composite material prepared from the integrated three-dimensional woven honeycomb fabric does not have the condition of fracture at a bonding part and has excellent mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of textile materials, and in particular to an integrated three-dimensional woven honeycomb fabric, a composite material thereof and a preparation method thereof. Background Art

[0002] Three-dimensional textile composites are an advanced type of composite material. They use preforms woven using fiber interlacing textile technology as reinforcements, resin as a matrix, and fiber bundles interlaced and interwoven in space to form an overall structure. Compared with traditional composite materials, three-dimensional textile composites overcome the defect of easy delamination and improve interlaminar shear strength and damage tolerance. The three-dimensional sandwich structure is a type of three-dimensional textile composite material that can maximize the reduction of structural weight while maintaining mechanical properties. Among them, the planar laminated honeycomb composite structure is formed by bonding and pressing planar materials in a laminated manner. The manufacturing method is simple, but the integrity of the component is poor, and the bonding joints are prone to rupture, resulting in poor mechanical properties. Therefore, it is urgent to provide an integrated three-dimensional woven honeycomb fabric with excellent mechanical properties. Summary of the invention

[0003] In view of this, the present invention provides an integrated three-dimensional woven honeycomb fabric and a composite material comprising the woven honeycomb fabric to solve the problem of poor mechanical properties caused by poor integrity of the existing honeycomb structure and easy rupture at the bonding point.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] On the one hand, the present invention provides an integrated three-dimensional woven honeycomb fabric, wherein each honeycomb side surface inclined to the warp direction is a single-layer structure, and the two sides parallel to the warp direction are formed by two adjacent overlapping plain weaves.

[0006] Preferably, the two overlapping plain weaves are joined using a corner interlocking structure.

[0007] Preferably, the woven honeycomb fabric has a regular hexagonal cross-section, and the number of weft yarns on each side of the honeycomb holes of the woven honeycomb is consistent and the number of openings is consistent.

[0008] Preferably, both the warp yarns and the weft yarns are high-performance fibers.

[0009] Preferably, the high-performance fiber is any one of carbon fiber, glass fiber, basalt fiber and poly(p-phenylene benzobisoxazole) fiber.

[0010] On the other hand, the present invention also provides a method for weaving the integrated three-dimensional woven honeycomb fabric described in any one of the above, comprising the following steps:

[0011] In a complete weaving cycle, the first warp yarn of each single layer passes through the adjacent heald frames in turn, and then passes into the same tooth. The two groups of warp yarns of each single layer do not contact each other before reaching the cloth fell.

[0012] When weaving two groups of warp yarns of the same single layer, the movement laws of the two groups of warp yarns are relatively symmetrical. When weaving the binding layer, the two double-layer warp yarns are a circulation unit, and the positions of the first layer of warp yarns and the fourth layer of warp yarns are exchanged.

[0013] Preferably, the two groups of warp yarns of each single layer do not contact each other before reaching the cloth fell:

[0014] The number of fully-woven warp yarns is equally divided into four groups, which are respectively inserted into four teeth to ensure that each single layer of warp yarn is inserted into one reed, and each single layer has a warp yarn in each tooth. Each layer of warp yarn is arranged longitudinally from high to low in the same reed tooth, and their relative positions remain unchanged when opening and closing during weaving, thereby reducing yarn wear caused by friction between the warp yarns.

[0015] On the other hand, the present invention also provides an integrated three-dimensional woven honeycomb composite material, including the integrated three-dimensional woven honeycomb fabric described in any one of the above items or the integrated three-dimensional woven honeycomb fabric prepared by any one of the preparation methods described in the above items.

[0016] Furthermore, the present invention also provides a method for preparing the above-mentioned integrated three-dimensional woven honeycomb composite material, comprising the following steps:

[0017] (1) placing an integrated three-dimensional woven honeycomb fabric in a curing mold, then delivering a resin solution into the curing mold, and stopping the delivery of the resin when the resin permeates the integrated three-dimensional woven honeycomb fabric;

[0018] (2) curing the material obtained in step (1), removing the curing mold and the hexagonal prism mold after the curing is completed, and obtaining an integrated three-dimensional woven honeycomb composite material through post-processing.

[0019] Preferably, the curing mold includes a box body, a first honeycomb mold and a second honeycomb mold, and the first honeycomb mold and the second honeycomb mold are both detachably arranged inside the box body; when the curing operation is performed, the integrated three-dimensional woven honeycomb fabric is fixed between the first honeycomb mold and the second honeycomb mold, and the surfaces of the first honeycomb mold and the second honeycomb mold facing the integrated three-dimensional woven honeycomb fabric are provided with grooves matching the shape of the integrated three-dimensional woven honeycomb fabric.

[0020] Preferably, the box body is provided with a top cover and a bottom cover, the inner surface of the top cover is in contact with and connected to the first honeycomb mold, and the second honeycomb mold is in contact with and connected to the inner surface of the bottom cover.

[0021] The present invention provides an integrated three-dimensional woven honeycomb fabric, a composite material thereof and a preparation method thereof. Compared with the prior art, the present invention has the following beneficial effects:

[0022] In the integrated three-dimensional woven honeycomb fabric prepared by the present invention, the warp and weft yarns are closely interwoven into one, and the integrity is good. The composite material prepared from the integrated three-dimensional woven honeycomb fabric will not break at the bonding point and has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 is a schematic diagram of the integrated three-dimensional woven honeycomb fabric of the present invention;

[0025] Figure 2 It is a schematic diagram of the preparation process of the integrated three-dimensional woven honeycomb fabric of the present invention;

[0026] Figure 3 The structure diagram of the integrated three-dimensional woven honeycomb fabric of the present invention;

[0027] Figure 4 This is a schematic diagram of the curing mold and assembly structure of the present invention;

[0028] Figure 5 A schematic diagram of the resin-infiltrated integrated three-dimensional woven honeycomb fabric of the present invention;

[0029] Figure 6 It is a structural schematic diagram of the hexagonal prism mold of the present invention;

[0030] Figure 7 This is a unit cell model diagram of an integrated three-dimensional woven honeycomb composite material;

[0031] Figure 8 Schematic diagram of experimental compression direction;

[0032] Fig. 9 is the compressive stress-strain curve in the out-of-plane direction;

[0033] Fig.10 This is the out-of-plane compression failure diagram of carbon fiber;

[0034] Fig.11 This is the out-of-plane compression failure diagram of glass fiber;

[0035] Fig.12 This is the out-of-plane compression failure diagram of basalt fiber;

[0036] Fig.13 is the compressive stress-strain curve along the warp fiber direction;

[0037] Fig.14 This is the compression failure diagram of carbon fiber along the warp direction;

[0038] Fig.15 This is the compression failure diagram of glass fiber along the warp yarn;

[0039] Fig.16 This is the compression failure diagram of basalt fiber along the warp direction.

[0040] In the figure:

[0041] 10-first fabric unit, 11-first fabric group, 12-second fabric group, 20-second fabric unit, 30-third fabric unit, 31-connecting node, 41-first warp yarn, 42-second warp yarn, 43-third warp yarn, 44-fourth warp yarn, 45-upper weft yarn, 46-lower weft yarn, 50-curing mold, 51-box, 511-top cover, 512-bottom cover, 52-first honeycomb mold, 53-second honeycomb mold, 61-liquid inlet conduit, 62-liquid outlet conduit, 63-liquid storage tank, 64-liquid storage tank, 70-integrated three-dimensional woven honeycomb fabric, 71-hexagonal prism mold, 72-front yarn. DETAILED DESCRIPTION

[0042] The present invention will be described below by specific examples, and it will be appreciated by those skilled in the art that the following specific examples are only for illustrative purposes, and do not limit the scope of the present invention in any way. In addition, in the following examples, unless otherwise specified, the reagents and equipment used are all commercially available. If in the following examples, specific treatment conditions and treatment methods are not clearly described, then conditions and methods known in the art can be used to process.

[0043] In one aspect of the present invention, Figure 1 As shown, the present invention proposes an integrated three-dimensional woven honeycomb fabric, wherein each honeycomb side surface inclined to the warp direction of the woven honeycomb fabric is a single-layer structure, and the two sides parallel to the warp direction are formed by two adjacent overlapping plain weaves.

[0044] In the integrated three-dimensional woven honeycomb fabric prepared by the present invention, the warp and weft yarns are closely interwoven into one, the integrity is good, no fracture occurs at the bonding point, and the fabric has excellent mechanical properties.

[0045] In some embodiments of the present invention, the two overlapping plain weaves are joined using a corner interlocking weave.

[0046] In some embodiments of the present invention, the woven honeycomb fabric has a regular hexagonal cross-section, and the number of weft yarns on each side of the honeycomb holes of the woven honeycomb is consistent and the number of openings is consistent.

[0047] In some embodiments of the present invention, both the warp yarns and the weft yarns are high-performance fibers, wherein the high-performance fibers include but are not limited to carbon fibers, glass fibers, and basalt fibers.

[0048] Specifically, in some embodiments of the present invention, the integrated three-dimensional woven honeycomb fabric is formed by interweaving a plurality of fabric units in the radial direction, and the woven honeycomb fabric is formed by stacking multiple layers of fabric in the axial direction, and each layer of fabric is connected to an adjacent layer of fabric by warp yarn or weft yarn to form a layered structure;

[0049] Among them, the fabric unit is hexagonal, and each fabric unit includes a first fabric group 11 and a second fabric group 12 located at the bottom of the first fabric group 11. The first fabric group 11 is formed by the first warp yarn 41, the second warp yarn 42 and the upper weft yarn 45 being interwoven with each other, and the second fabric group 12 is formed by the third warp yarn 43, the fourth warp yarn 44 and the lower weft yarn 46 being interwoven with each other.

[0050] Along the first radial direction of the woven honeycomb fabric, the fabric unit includes a first fabric unit 10 and a second fabric unit 20 located at the bottom of the first fabric unit 10, and the second fabric group 12 of the first fabric unit 10 is interwoven with the first fabric group of the second fabric unit 20 to achieve the connection between the first fabric unit 10 and the second fabric unit 20.

[0051] Along the second radial direction of the woven honeycomb fabric, the fabric unit includes a first fabric unit 10 and a third fabric unit 30 , and the first fabric unit 10 and the third fabric unit 30 are connected by a connection joint 31 .

[0052] Optionally, the connection node 31 is formed by interweaving the first warp yarn 41, the second warp yarn 42, the third warp yarn 43, the fourth warp yarn 44 with the upper weft yarn 45 and the lower weft yarn 46; the first radial direction and the second radial direction are perpendicular to each other.

[0053] It can be understood that in the first radial direction, the integrated connection of the fabrics is achieved through adjacent fabric groups between different fabric units, and in the second radial direction, the integrated connection of adjacent fabric units is achieved through the connecting nodes 31, ultimately obtaining an integrated three-dimensional woven honeycomb fabric with good integrity of the present invention.

[0054] In another aspect of the present invention, the present invention also provides a weaving method for an integrated three-dimensional woven honeycomb fabric. The preparation of the integrated three-dimensional woven honeycomb fabric is completed on a three-dimensional angle interlocking loom. An air pump connected to the three-dimensional angle interlocking loom is used to move the horizontal rows on the loom as a whole to weave an integrated three-dimensional woven honeycomb fabric.

[0055] Specifically, the weaving method of the integrated three-dimensional woven honeycomb fabric includes the following steps:

[0056] (1) Figure 2 As shown, with warp and weft as raw materials, according to Figure 1 The integrated three-dimensional woven honeycomb fabric shown is woven with at least one loop as the front edge yarn 72 .

[0057] In this step, the front yarn 72 is used to fix the entire fabric structure, so the hexagonal prism mold 71 is not placed during the weaving process of the front yarn 72, and the weaving cycle can be 1, 1.5, 2, 2.5, 3 or more, without special limitation.

[0058] For the specific weaving process, see Figure 3 The organization diagram shown divides the weaving part into four steps:

[0059] S1: Insert six weft yarns into the black and green, red and blue warp yarns respectively;

[0060] S2: Move all blue and black warp systems to the opposite direction, insert six weft yarns into the openings formed by blue and green, red and black respectively, and place the hexagonal prism mold into the black and blue warp yarn openings;

[0061] S3: Same as step S1.

[0062] S4: Exchange the warp yarn positions as in step S2, but this action only occurs in the middle 8 layers of warp yarns. Swap the red warp yarn with the green warp yarn, and place the six weft yarns into the openings formed by the green and black, green and blue, black and red, green and blue, black and red, and blue and red warp yarns respectively. Place the hexagonal prism mold into the warp yarn openings of black and green, red and green, and red and blue.

[0063] (2) Continue the cyclic weaving, place the hexagonal prism mold 71 during the weaving process of each fabric unit, pass the weft yarn into each opening of the warp yarn in sequence according to the shuttle number sequence, and use the heald frame to tighten the weft yarn axially so that each fabric unit is covered on the surface of the hexagonal prism mold 71.

[0064] In this step, the hexagonal prism mold 71 needs to be cleaned and polished before use until there are no obvious protrusions and it has a smooth surface, and its surface is coated with a release agent to facilitate later demolding and recycling.

[0065] In some embodiments of the present invention, the tightening force (also known as the weft beating force) is 30-35N, for example, it can be 30N, 31N, 32N, 33N, 34N, 35N, etc., so that the fabric has sufficient tightness; preferably, the weft beating force is the same each time to ensure that the fibers of the warp yarn and the weft yarn can be evenly covered on the surface of the hexagonal prism mold 71.

[0066] It should be noted that, under a certain tension, the greater the force of beating, the tighter the fabric, and the greater the surface coverage of the mold by the fiber. However, if the force is too great, the high-performance fiber may break.

[0067] (3) Continue to weave in a loop until the fabric length reaches a preset weaving length, weave at least one loop as the back yarn, cut off the excess yarn part, and obtain an integrated three-dimensional woven honeycomb fabric 70.

[0068] In this step, the back yarn is also used to fix the entire fabric structure, and the weaving cycle can be 1, 1.5, 2, 2.5, 3 or more, without special limitation.

[0069] In some embodiments of the present invention, integrated three-dimensional woven honeycomb fabrics of different fiber types and different pore sizes can be prepared by calculation. For example, it has been found through experiments that when carbon fiber is used as the raw material, if the surface of the hexagonal prism mold 71 with a diameter of 7 mm is to be completely covered, the fiber used is 12K fiber of T700, in which the warp yarn is 12K and the weft yarn is 24K, and the steel reed used is 1 cm 3 reed.

[0070] (1) Based on the cross-sectional area of ​​12K carbon fiber, the diameter of the single fiber is 7 μm, and the carbon fiber body density is 1.78 g / cm 3 , the line density is Tt c , calculated by the formula:

[0071]

[0072] It can be concluded that the cross-sectional area of ​​12K carbon fiber is 4.4×10 -3 cm 2 , where ρ c represents the carbon fiber volume density, s c Represents the cross-sectional area of ​​12K carbon fiber.

[0073] (2) Based on the cross-sectional area of ​​12K carbon fiber, combined with the density of basalt fiber and glass fiber, the linear density of another fiber required is calculated using the following formula:

[0074] Tt b =s c ×ρ b

[0075] Tt g =s c ×ρ g ,

[0076] Where ρb represents the bulk density of basalt fiber, ρ g Represents the bulk density of glass fiber, Tt b Represents the linear density of basalt fiber, Tt g Represents the linear density of glass fiber.

[0077] The above formula can be used to calculate the linear density of other types of high-performance fibers such as glass fiber and basalt fiber, which can provide data support for the subsequent preparation of woven hybrid fiber honeycomb composite materials.

[0078] In some embodiments of the present invention, Figure 6 As shown, the fiber volume content of the high-performance fiber can be obtained by calculation. Specifically, the length of the hexagonal prism mold 71 can be set to d, the aperture of the opposite side can be set to a1, and when the warp and weft yarns completely cover the hexagonal prism mold 71, the area required to be covered by the warp and weft yarns is 6a1d, the ratio of the warp and weft yarns covering the mold surface is 1:1, and the coverage ratio is S ％ , the fiber volume content is V ％ =0.26S ％ (Experiments have shown that when the coverage is 100%, the fiber volume content is 26%).

[0079] In another aspect of the present invention, the present invention further provides an integrated three-dimensional woven honeycomb composite material, including any of the above-mentioned integrated three-dimensional woven honeycomb fabrics 70 or the integrated three-dimensional woven honeycomb fabric 70 prepared by any of the above-mentioned preparation methods. Since the integrated three-dimensional woven honeycomb composite material includes the integrated three-dimensional woven honeycomb fabric 70, it has all the characteristics of the integrated three-dimensional woven honeycomb fabric 70, which will not be repeated here.

[0080] In another aspect of the present invention, the present invention also provides a method for preparing the above-mentioned integrated three-dimensional woven honeycomb composite material, comprising the following steps:

[0081] (1) The integrated three-dimensional woven honeycomb fabric 70 is placed in the curing mold 50, and then the resin solution is conveyed into the curing mold 50. When the resin permeates the integrated three-dimensional woven honeycomb fabric 70, the resin conveying is stopped.

[0082] In this step, if Figure 4 As shown, the curing mold 50 includes a box body 51, a first honeycomb mold 52 and a second honeycomb mold 53, and the first honeycomb mold 52 and the second honeycomb mold 53 are both detachably arranged inside the box body 51; when the curing operation is performed, the integrated three-dimensional woven honeycomb fabric 70 is fixed between the first honeycomb mold 52 and the second honeycomb mold 53, and the surfaces of the first honeycomb mold 52 and the second honeycomb mold 53 facing the integrated three-dimensional woven honeycomb fabric 70 are provided with grooves matching the shape of the integrated three-dimensional woven honeycomb fabric 70. Preferably, the box body 51 is provided with a top cover 511 and a bottom cover 512, the inner surface of the top cover 511 is in contact with the first honeycomb mold 52, and the second honeycomb mold 53 is in contact with the inner surface of the bottom cover 512; more preferably, the contact connection is a soft contact connection, for example, a groove is circumferentially arranged on the inner surface of the top cover 511 and the bottom cover 512, and a silicone strip is arranged in the groove to reduce or avoid damage to the honeycomb mold and ensure the airtightness of the curing mold 50.

[0083] It should be noted that the curing mold 50 is cleaned before use, and a release agent is fully applied to at least one side of the first honeycomb mold 52 and the second honeycomb mold 53 that are in contact with the integrated three-dimensional woven honeycomb fabric 70 and dried to form a film, so as to facilitate subsequent demolding.

[0084] In some embodiments of the present invention, the resin solution can be a material conventionally used in curing treatment without special limitation. For example, the resin solution is mainly composed of an epoxy resin and a curing agent with a molar ratio of 1:0.85. After the epoxy resin and the curing agent are evenly mixed, they are dried in a 60°C blast drying oven for 10-30 minutes to discharge large bubbles in the mixed solution and avoid the formation of large bubbles in the composite material, thereby affecting the mechanical properties of the composite material; then the container containing the mixed solution is placed in a vacuum drying furnace and vacuumed at 60°C for 2 hours to obtain a resin solution. For another example, the resin solution is mainly composed of a resin monomer, a curing agent and a catalyst with a molar ratio of 1:2:0.05. The catalyst is first added to the resin monomer, stirred at 160°C until the catalyst is completely dissolved, then cooled to 70°C, the curing agent is added, and the curing agent is stirred at a constant temperature until the curing agent is completely dissolved. When the mixed solution becomes transparent and uniform and free of bubbles, the resin solution is obtained.

[0085] In some embodiments of the present invention, Figure 5As shown, before the curing treatment, the integrated three-dimensional woven honeycomb fabric 70 is installed in the curing mold 50, and the curing mold 50 is assembled, and then at least one liquid inlet conduit 61 is taken, one end of which is connected to one side of the first honeycomb mold 52 and the second honeycomb mold 53, and the other end is connected to the liquid storage tank 63 containing the resin solution for feeding resin; at least one liquid outlet conduit 62 is taken, one end of which is connected to the other side of the first honeycomb mold 52 and the second honeycomb mold 53, and the other end is connected to the liquid outlet tank 64 for draining out excess resin; and the connection between the liquid inlet conduit 61, the liquid outlet conduit 62 and the box body 51 is blocked to prevent air leakage.

[0086] In some embodiments of the present invention, an air tightness test is also included before the curing process. The air tightness test method is as follows: the liquid inlet conduit 61 is sealed, the liquid outlet conduit 62 is connected to the vacuum pump, and the vacuum pump is turned on to check the air tightness of the curing mold 50. After confirming that the fabric is in a vacuum state, the liquid outlet conduit 62 is closed, and it is left to stand for 0.5 hours to observe whether there is any leakage. If there is no leakage, the air tightness test is completed.

[0087] In some embodiments of the present invention, after the air tightness test is completed, the switches of the liquid inlet duct 61 and the liquid outlet duct 62 are opened, so that the resin solution enters the curing mold 50 through the liquid inlet duct 61 and infiltrates the integrated three-dimensional woven honeycomb fabric 70. After the resin solution fully infiltrates the integrated three-dimensional woven honeycomb fabric 70, the liquid inlet duct 61 and the liquid outlet duct 62 are blocked, and then the sealed curing mold 50 is placed in an oven for curing treatment.

[0088] (2) The material obtained in step (1) is subjected to a curing treatment. After the curing treatment is completed, the curing mold 50 and the hexagonal prism mold 71 are removed, and after post-treatment, an integrated three-dimensional woven honeycomb composite material is obtained.

[0089] In this step, the curing process is a conventional scheme, which can be selected according to actual conditions and is not particularly limited. For example, corresponding to the scheme in which the aforementioned resin solution is mainly composed of epoxy resin and curing agent with a molar ratio of 1:0.85, the curing procedure is as follows: after the oven is preheated at the initial temperature for 10 minutes, it is heated to 90°C and operated for 120 minutes, and then heated to 110°C within 10 minutes and operated for 60 minutes, and then heated to 135°C within 10 minutes and operated for 360 minutes, and the curing is completed, wherein 90°C is the resin gel state temperature, 110°C is the resin curing state temperature, and 135°C is the resin post-curing state temperature. For another example, corresponding to the scheme that the resin solution is mainly composed of a resin monomer, a curing agent and a catalyst in a molar ratio of 1:2:0.05, the curing procedure is as follows: run at 140°C for 120 minutes, heat up to 160°C within 5-10 minutes and run for 240 minutes, continue to heat up to 180°C within 5-10 minutes and run for 60 minutes, and the curing is completed, wherein 140°C is the resin gel state temperature, 160°C is the resin curing state temperature, and 180°C is the resin post-curing state temperature. In the experimental test of the embodiment of the present invention, the scheme and curing procedure in which the resin solution is mainly composed of an epoxy resin and a curing agent in a molar ratio of 1:0.85 are used.

[0090] In some embodiments of the present invention, after the curing process is completed and cooled for a period of time, the curing mold 50 can be removed by a hot pressing molding machine and the cured woven honeycomb fabric can be taken out. After its surface is cleaned, it enters the demolding stage of the hexagonal prism mold 71. The hexagonal prism mold 71 can be knocked out with a hammer or an iron rod of suitable size.

[0091] In some embodiments of the present invention, the post-processing is to cut off the resin on both sides of the solidified woven honeycomb fabric and the solidified edge yarn parts by using a cutting machine.

[0092] In some embodiments of the present invention, Figure 7 As shown in the figure, it is a unit cell model of an integrated three-dimensional woven honeycomb composite material. In the figure, W represents the width of the unit cell, H represents the height of the unit cell, A represents the side length of a hexagon in the unit cell, a2 represents the side length of the mold, t represents the thickness of the fiber and resin after the yarn is cured around the mold with a hexagonal aperture, and θ represents the angle of the hexagon. According to the above parameters, the calculation formula for the fiber yarn amount is as follows:

[0093]

[0094] mj+mw=V m ρ

[0095]

[0096] L=Lj+Lw

[0097] Where: V-the volume of a unit cell, d-the width of the honeycomb unit cell, ρ-the fiber density, b j -Linear density of fiber warp direction, b w - linear density of the fiber in the warp direction, t-weaving shrinkage (generally, the shrinkage of carbon fiber is 10%), c-number of reeds per centimeter of the reed, V m - The sum of the volumes of all fibers, V ％ -Fiber volume content, m j -The weight of the warp fibers in a single cell, m w -The weight of the latitudinal fibers in a unit cell, b j -Linear density of warp fibers, b w - Linear density of weft fibers, L j -The amount of warp yarn per unit cell, L w -The amount of weft yarn used in the single cell unit, L-the amount of yarn used in the single cell unit. Based on the above formula, the amount of yarn used in the integrated three-dimensional woven honeycomb fabric can be calculated.

[0098] The integrated three-dimensional woven honeycomb composite material prepared by the above method is used as the honeycomb core, and the two-dimensional carbon fiber woven plain cloth composite material is used as the panel. The honeycomb core is cured between the two panels and used as the test sample to carry out compression performance tests in two different directions. The compression performance test refers to GB / T1446-2005 standard and is carried out on a universal testing machine.

[0099] The present invention conducts compression performance tests in two different directions on single cells of the same specification of three different high-performance fiber reinforced fabrics, namely carbon fiber, basalt fiber and glass fiber. In the compression performance test, the amount of yarn used for each high-performance fiber is 173g, and the resin solution used in the curing process is mainly composed of epoxy resin JC02-A and curing agent JC02-B with a molar ratio of 1:0.85. The curing procedure refers to the aforementioned part. In order to ensure sufficient infiltration during the curing process, the amount of resin solution is 1200g. Specifically, the compression performance of the sample to be tested is tested with the type of high-performance fiber as a variable. The first compression direction is perpendicular to both the warp yarn and the weft yarn, and the second compression direction is perpendicular to the weft yarn and along the warp yarn. Figure 8 As shown, the direction of arrow 1 is the uniform loading direction, and the direction of arrow 2 remains unchanged.

[0100] The compression test on the sample in the out-of-plane direction was carried out on a universal testing machine to derive the displacement-load curve of the compression specimen. The out-of-plane compressive stress and compressive strain values ​​of the three-dimensional woven honeycomb samples with different fiber reinforcements were obtained using formulas (1) and (2).

[0101]

[0102] In formula (1) and formula (2):

[0103] σ-compression stress of the test compression specimen, in megapascals (MPa);

[0104] P-The load on the test compression specimen, in Newton (N);

[0105] S-The area of ​​the test compression specimen under load, in square millimeters (mm 2 );

[0106] ε-compression strain of the test compression specimen, no unit;

[0107] ΔL-deformation length of the test specimen in the compression test, in millimeters (mm);

[0108] L-test compression specimen is the height of the specimen along the compression direction, in millimeters (mm).

[0109] In the out-of-plane compression test, the S value is 76 mm. 2 , L is 30 mm, and S is 213 mm in the longitudinal compression test. 2 , the value of L is 24mm.

[0110] 1. Analysis of compressive stress-strain curve in out-of-plane direction

[0111] The processed values ​​are plotted using the Origin software to obtain the compressive stress-strain curve outside the sample surface, as shown in Fig. 9 As shown. The following conclusions can be drawn from the figure: At the beginning, the three curves all showed a linear upward trend. In terms of slope, the glass fiber reinforced three-dimensional woven honeycomb composite material was slightly larger than the carbon fiber reinforced three-dimensional woven honeycomb composite material, and the carbon fiber reinforced three-dimensional woven honeycomb composite material was slightly larger than the basalt fiber reinforced three-dimensional woven honeycomb composite material. With the increase of strain, the stress increases faster and faster. It can be seen from the figure that the maximum stress that the carbon fiber reinforced three-dimensional woven honeycomb composite material can withstand is greater than that of the glass fiber reinforced three-dimensional woven honeycomb composite material, and the bearing capacity of the glass fiber reinforced three-dimensional woven honeycomb composite material is greater than that of the basalt fiber reinforced three-dimensional woven honeycomb composite material.

[0112] The slopes of the three curves, i.e., the elastic modulus of the out-of-plane compression of the three-dimensional honeycomb composite material, were obtained by data fitting, and the data in Table 1 were obtained.

[0113] Table 1 Elastic modulus of different fibers under out-of-plane compression

[0114] Fiber Type Elastic modulus / GPa Fiberglass 0.483 Basalt fiber 0.221 Carbon Fiber 0.476

[0115] It can be concluded from Table 1 that the elastic modulus of the glass fiber reinforced three-dimensional woven honeycomb composite material is slightly greater than that of the carbon fiber reinforced three-dimensional woven honeycomb composite material, with a difference of 1.86%; while the elastic modulus of the glass fiber reinforced three-dimensional woven honeycomb composite material is slightly greater than that of the basalt fiber reinforced three-dimensional woven honeycomb composite material, with a difference of 44.45%.

[0116] 2. Analysis of the failure morphology of the compressed sample in the out-of-plane direction

[0117] like Fig.10 As shown in the figure, some fibers of the carbon fiber reinforced three-dimensional woven honeycomb composite material are broken, the matrix is ​​damaged, but the interface is not greatly affected. The matrix is ​​damaged first, and the force is transmitted through the interface to further damage the carbon fiber. Since the interface between the carbon fiber and the resin is good, the interface damage of the carbon fiber is not very obvious when the force is transmitted;

[0118] like Fig.11 As shown in the figure, the damage forms of the glass fiber reinforced three-dimensional woven honeycomb composite material and the carbon fiber reinforced three-dimensional woven honeycomb composite material are roughly the same, the fiber part is broken, the matrix part is damaged, but the interface between the glass fiber and the resin is more obviously damaged than that of the carbon fiber, and the interface strength between the glass fiber and the resin is not as good as that of the carbon fiber. Therefore, it can be seen from the figure that the interface damage of the glass fiber reinforced three-dimensional woven honeycomb composite material is obvious;

[0119] like Fig.12 The figure shows a basalt fiber reinforced three-dimensional woven honeycomb composite material. The fiber breakage is obvious, the matrix is ​​greatly affected, and the interface between the resin and the fiber is obviously damaged, with stratification. This is because the interface between the basalt fiber and the resin is the weakest of the three types of fibers, so the interface damage of the basalt fiber reinforced three-dimensional woven honeycomb composite material is the most serious.

[0120] Therefore, the out-of-plane compression is greatly affected by the interface between the resin and the fiber. In actual operation, the appropriate fiber type can be selected according to the actual situation.

[0121] 3. Analysis of compressive stress-strain curve along the warp fiber direction

[0122] By using the compression test on the sample along the warp fiber direction on a universal testing machine to derive the compression pattern displacement-load curve, the compressive stress and compressive strain values ​​of the three-dimensional woven honeycomb composite materials with different fiber reinforcements along the warp yarn can be obtained using formulas (1) and (2).

[0123] The processed values ​​were plotted using the Origin software to obtain the compressive stress-strain curve of the sample along the warp direction of the yarn, as shown in Fig.13As shown in the figure, the following conclusions can be drawn from the figure: At the beginning, the three curves all showed a linear upward trend. In terms of slope, the basalt fiber reinforced three-dimensional woven honeycomb composite material was greater than the glass fiber reinforced three-dimensional woven honeycomb composite material, and the glass fiber reinforced three-dimensional woven honeycomb composite material was greater than the basalt fiber reinforced three-dimensional woven honeycomb composite material. With the increase of strain, the stress increase rate is getting faster and faster. Among them, the slope of the basalt fiber reinforced three-dimensional woven honeycomb composite material increases the fastest, followed by the glass fiber reinforced three-dimensional woven honeycomb composite material, and finally the carbon fiber reinforced three-dimensional woven honeycomb composite material. It can be seen from the figure that the maximum stress that the basalt fiber reinforced three-dimensional woven honeycomb composite material can withstand is greater than that of the glass fiber reinforced three-dimensional woven honeycomb composite material, and the bearing capacity of the glass fiber reinforced three-dimensional woven honeycomb composite material is greater than that of the carbon fiber reinforced three-dimensional woven honeycomb composite material.

[0124] The slopes of the three curves, i.e., the elastic modulus of the three-dimensional honeycomb composite material compressed along the longitudinal fiber direction, were obtained by data fitting, and the data in Table 2 were obtained.

[0125] Table 2 Elastic modulus of different fibers under out-of-plane compression

[0126] Fiber Type Elastic modulus / GPa Fiberglass 0.1896 Basalt fiber 0.2984 Carbon Fiber 0.1051

[0127] It can be seen from Table 2 that the elastic modulus of the basalt fiber reinforced three-dimensional woven honeycomb composite material is greater than that of the glass fiber reinforced three-dimensional woven honeycomb composite material, with a difference of 36.46%; while the elastic modulus of the basalt fiber reinforced three-dimensional woven honeycomb composite material is greater than that of the carbon fiber reinforced three-dimensional woven honeycomb composite material, with a difference of 64.78%.

[0128] 4. Analysis of the failure morphology of compressed samples along the warp fiber direction

[0129] like Fig.14 As shown in the figure, some fibers of the carbon fiber reinforced three-dimensional woven honeycomb composite material are broken, the matrix is ​​damaged, and the interface is damaged, but it is relatively not greatly affected. This is because the shear modulus of carbon fiber is small, so when the force is transmitted to the fiber, the fiber is quickly damaged after being sheared.

[0130] like Fig.15 As shown in the figure, the damage morphology of the glass fiber reinforced three-dimensional woven honeycomb composite material and the carbon fiber reinforced three-dimensional woven honeycomb composite material is roughly the same. The fibers are not damaged even when exposed. The matrix is ​​partially damaged, but the interface between the glass fiber and the resin is less damaged than that of the carbon fiber. This is because the glass fiber is an isotropic material with a higher shear modulus, and the fiber can withstand a larger shear damage force.

[0131] like Fig.16 As shown in the figure, the fiber breakage of the basalt fiber reinforced three-dimensional woven honeycomb composite material is obvious, the matrix is ​​greatly affected, and the interface between the resin and the fiber is obviously damaged and stratified. This is because although the interface between the matrix and the resin of the basalt fiber reinforced three-dimensional woven honeycomb composite material is weak, the shear force that its fibers can withstand is large, so the woven honeycomb composite material can withstand a large load.

[0132] In summary, in the out-of-plane compression direction, the stress value of the carbon fiber reinforced three-dimensional woven honeycomb composite material is the largest. Compared with glass fiber and basalt fiber, the maximum stress values ​​of carbon fiber increased by 9.85% and 43.40%, respectively. This means that when compressed in the out-of-plane direction, the shear strength that carbon fiber can withstand is greater than that of glass fiber and basalt fiber. The degree of interface damage is also the weakest for carbon fiber, followed by glass fiber, and the strongest for basalt fiber. That is, when compressed in this direction, the role of the interface is indispensable.

[0133] In the direction of compression of the warp fibers, the stress value of the basalt fiber reinforced three-dimensional woven honeycomb composite material is the largest. Compared with glass fiber and carbon fiber, the maximum stress value of basalt fiber increases by 40.00% and 31.15% respectively, which means that the shear strength that basalt fiber can withstand is greater than that of glass fiber and carbon fiber when compressed along the warp fiber direction. The compression in this direction is greatly affected by the properties of the fiber itself. From the properties of the fiber, it can be seen that along the warp fiber, the elastic modulus of basalt fiber is greater than that of glass fiber, and the elastic modulus of glass fiber is greater than that of carbon fiber. In actual use, high-performance fiber types can be selected according to actual conditions.

[0134] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An integrated three-dimensional woven honeycomb fabric, characterized in that: The honeycomb side surfaces of the woven honeycomb fabric inclined to the warp direction are single-layer structures, and the two sides parallel to the warp direction are formed by connecting two adjacent overlapping plain weaves.

2. The integrated three-dimensional woven honeycomb fabric according to claim 1, characterized in that: The two overlapping plain weaves are joined using a corner interlocking structure.

3. The integrated three-dimensional woven honeycomb fabric according to claim 1, characterized in that: The woven honeycomb fabric has a regular hexagonal cross section, and the number of weft yarns on each side of the honeycomb holes of the woven honeycomb is consistent and the number of openings is consistent.

4. The integrated three-dimensional woven honeycomb fabric according to any one of claims 1 to 3, characterized in that: The warp yarns and the weft yarns are both high-performance fibers; The high-performance fiber is any one of carbon fiber, glass fiber, basalt fiber or poly(p-phenylene benzobisoxazole) fiber.

5. A method for weaving the integrated three-dimensional woven honeycomb fabric according to any one of claims 1 to 4, characterized in that: The following steps are involved: In a complete weaving cycle, the first warp yarn of each single layer passes through the adjacent heald frames in turn, and then passes into the same tooth. The two groups of warp yarns of each single layer do not contact each other before reaching the cloth fell. When weaving two groups of warp yarns of the same single layer, the movement laws of the two groups of warp yarns are relatively symmetrical. When weaving the binding layer, the two double-layer warp yarns are a circulation unit, and the positions of the first layer of warp yarns and the fourth layer of warp yarns are exchanged.

6. The weaving method of the integrated three-dimensional woven honeycomb fabric according to claim 5, characterized in that: The two groups of warp yarns of each single layer do not contact each other before reaching the cloth fell: The number of fully-woven warp yarns is equally divided into four groups and respectively inserted into four teeth. Each single layer in each tooth has a warp yarn. Each layer of warp yarns is arranged longitudinally from high to low in the same reed tooth, and their relative positions remain unchanged when opening and closing during weaving.

7. An integrated three-dimensional woven honeycomb composite material, characterized in that: It comprises the integrated three-dimensional woven honeycomb fabric described in any one of claims 1 to 4 or the integrated three-dimensional woven honeycomb fabric prepared by the preparation method described in any one of claims 5 to 6.

8. A method for preparing the integrated three-dimensional woven honeycomb composite material according to claim 7, characterized in that: The following steps are involved: (1) placing an integrated three-dimensional woven honeycomb fabric in a curing mold, then delivering a resin solution into the curing mold, and stopping the delivery of the resin when the resin permeates the integrated three-dimensional woven honeycomb fabric; (2) curing the material obtained in step (1), removing the curing mold and the hexagonal prism mold after the curing is completed, and obtaining an integrated three-dimensional woven honeycomb composite material through post-processing.

9. The method for preparing the integrated three-dimensional woven honeycomb composite material according to claim 8, characterized in that: The curing mold comprises a box body, a first honeycomb mold and a second honeycomb mold, wherein the first honeycomb mold and the second honeycomb mold are both detachably arranged inside the box body; When the curing operation is performed, the integrated three-dimensional woven honeycomb fabric is fixed between the first honeycomb mold and the second honeycomb mold, and the surfaces of the first honeycomb mold and the second honeycomb mold facing the integrated three-dimensional woven honeycomb fabric are provided with grooves matching the shape of the integrated three-dimensional woven honeycomb fabric.

10. The method for preparing the integrated three-dimensional woven honeycomb composite material according to claim 9, characterized in that: The box body is provided with a top cover and a bottom cover, the inner surface of the top cover is in contact with and connected to the first honeycomb mold, and the second honeycomb mold is in contact with and connected to the inner surface of the bottom cover.

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