WO2021033484A1

WO2021033484A1 - Fiber structure and fiber-reinforced composite

Info

Publication number: WO2021033484A1
Application number: PCT/JP2020/028417
Authority: WO
Inventors: 神谷隆太
Original assignee: 株式会社豊田自動織機
Priority date: 2019-08-19
Filing date: 2020-07-22
Publication date: 2021-02-25
Also published as: JP7322588B2; JP2021030478A

Abstract

This fiber structure (11) comprises a first fiber base material (12) and a second fiber base material (20). The first fiber base material (12) has a main body portion (11a) in which a plurality of fiber layers (13a, 13b) of reinforcing fibers are laminated, and a branched portion (18) in which the main body portion (11a) branches in two along the lamination direction (Z) of the fiber layers (13a, 13b). The second fiber base material (20) covers the branched portion (18) and is integrated with the first fiber base material (12). The fiber structure (11) comprises space-filling members (30, 40) that fill spaces (S) defined by the branched portion (18) and the second fiber base material (20), the space-filling members (30, 40) being fiber bundles of discontinuous fibers (H).

Description

Fiber structure and fiber reinforced composite

The present disclosure relates to a fiber structure and a fiber reinforced composite material including a gap filling member that fills the gap.

Fiber reinforced composite material is used as a lightweight and high-strength material. A fiber-reinforced composite material is preferable as a structural component because a fiber structure made of reinforced fibers is composited in a matrix material such as a resin or a metal to improve mechanical properties as compared with the matrix material itself. In particular, when a resin is used as the matrix material, the weight of the structural parts can be reduced, which is preferable.

As a fiber reinforced composite material of this type, for example, there is one formed in an I shape or a T shape (see, for example, Patent Document 1). The reinforcing base material of the reinforcing material disclosed in Patent Document 1 includes a pair of C channels arranged back to back. Each pair of C-channels includes a web portion and flanges provided at each end of the web portion and extending in opposite directions with the pair of C-channels.

The pair of web parts are connected to form a reinforcing material web. In the reinforced base material, a cap is connected to the outside of the pair of flanges on one end side of the web, and a base is connected to the outside of the pair of flanges on the other end side of the web. Therefore, the reinforced base material is composed of a pair of C channels, a cap, and a base.

In the reinforced base material, a gap having a triangular cross section is defined between the pair of C channel flanges and the cap, and between the pair of C channel flanges and the base. A reinforcing filler having a triangular cross section almost the same as the gap is filled. As the reinforcing filler, a composite tape, a cloth member, or the like is adopted. The surface of the C channel surrounding the gap is covered with a cloth layer. Further, in the gap, an adhesive layer is provided inside the cloth layer, and the reinforcing filler is wrapped in the adhesive layer. Then, the periphery of the gap in the reinforcing material is reinforced by these cloth layers, the adhesive layer, and the reinforcing filler.

Japanese Patent Publication No. 2011-520690

However, in Patent Document 1, in order to reinforce the periphery of the gap in the reinforcing material, a cloth layer, an adhesive layer, and a reinforcing filler are required, and the cloth layer, the adhesive layer, and the reinforcing filler are required. There was a problem that the work for providing the above was troublesome.

An object of the present disclosure is to provide a fiber structure and a fiber reinforced composite that can easily perform the work necessary for reinforcing the periphery of the gap in the fiber reinforced composite.

The fiber structure for solving the above problems is the fiber structure of the fiber-reinforced composite material formed by impregnating the fiber structure with a matrix material, and the main body portion in which a plurality of fiber layers of the reinforcing fibers are laminated. The first fiber base material having a branch portion in which the main body portion is bifurcated along the laminating direction of the fiber layer and the first fiber base material covering the branch portion are integrated with the first fiber base material. A second fiber base material is provided, and a gap filling member filled in a gap defined by the branch portion and the second fiber base material is provided, and the gap filling member is a fiber bundle of discontinuous fibers. The gist is that.

The fiber-reinforced composite material for solving the above problems is a fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material, and the fiber structure is any one of claims 1 to 4. The gist is that it is the fiber structure described in paragraph 1.

In each configuration, the gap filling member is a branch portion of the first fiber base material before the first fiber base material and the second fiber base material are integrated, that is, before the branch portion is covered with the second fiber base material. Is placed in. After that, the branch portion is covered with the second fiber base material, so that the gap is defined and the gap filling member is filled.

The gap filling member is a string shape because it is a fiber bundle of discontinuous fibers. For this reason, for example, compared to the case where the non-woven fabric is arranged at the branch portion, it is easier to handle, and unlike the non-woven fabric, it is not necessary to shape the non-woven fabric into the shape of the branch portion, so that the work of arranging the gap filling member at the branch portion is easy. Is.

Then, in the fiber-reinforced composite material produced by impregnating the fiber structure with a matrix material, the periphery of the gap is reinforced by discontinuous fibers. The amount of discontinuous fibers filled in the gap can be adjusted to an amount suitable for reinforcement only by adjusting the number of gap filling members filled in the gap. Therefore, for example, as compared with the case where a plurality of types of reinforcing materials are prepared to reinforce the circumference of the gap or a reinforcing member that follows the shape of the gap is manufactured, the gap in the fiber reinforced composite material The work required to reinforce the surroundings can be easily performed.

Regarding the fiber structure, the second fiber base material has a plurality of fiber layers of reinforcing fibers laminated, and the direction of laminating the fiber layer in the second fiber base material and the direction of laminating the fiber layer in the main body portion. Assuming that the direction orthogonal to is the depth direction, the branch portion extends continuously along the depth direction, and the gap extends over the entire depth direction of the fiber structure and is the axial direction of the gap filling member. The dimension to is 60% or more of the dimension of the gap in the depth direction.

According to this, the discontinuous fibers of the gap filling member are oriented so as to extend in the depth direction of the main body. Therefore, in the fiber-reinforced composite material produced by impregnating the fiber structure with the matrix material, the strength in the depth direction can be ensured by the gap filling member.

For the fiber structure, the fiber volume content indicating the amount of the discontinuous fibers per unit volume of the gap is equal to or less than the fiber volume content indicating the amount of the reinforcing fibers per unit volume in the main body. Good.

According to this, the ratio of the discontinuous fibers of the gap filling member in the gap does not become too high, and it is suppressed that the discontinuous fibers are densely overlapped with each other. As a result, in the gap filling member arranged in the gap, the matrix material is likely to be impregnated between the discontinuous fibers.

Regarding the fiber structure, the gap filling member may include a core thread made of continuous fibers extending in the entire axial direction of the gap filling member, and a coating layer made of discontinuous fibers covering the core thread.

According to this, it is easy to maintain the shape of the gap filling member having straightness by the core thread, and it is easy to arrange the gap filling member at the branch portion.

According to the present disclosure, the work required to reinforce the periphery of the gap in the fiber reinforced composite material can be easily performed.

The perspective view which shows the fiber reinforced composite material of embodiment. A partial cross-sectional view showing a fiber structure. The figure which shows the gap schematically. The schematic diagram which shows the gap filling member. The figure which shows typically the state which arranges the gap filling member. The figure which shows the state of manufacturing a fiber structure. The schematic diagram which shows another example of the gap filling member.

Hereinafter, an embodiment in which the fiber structure and the fiber-reinforced composite material are embodied will be described with reference to FIGS. 1 to 6.
As shown in FIG. 1, the fiber-reinforced composite material 10 is formed by impregnating and curing a matrix resin Ma, which is an example of a matrix material, in a fiber structure 11 having a T-shaped cross section. The fiber structure 11 has a rectangular plate-shaped main body portion 11a and a flange 11b orthogonal to the main body portion 11a. The fiber structure 11 is defined between the first fiber base material 12 having a T-shaped cross section, the second fiber base material 20 having a flat plate shape, and the first fiber base material 12 and the second fiber base material 20. It has a gap filling member 30 that fills the gap S.

The first fiber base material 12 is formed by joining two L-shaped fiber bodies 13 to form a T-shaped cross section. The L-shaped fiber body 13 is composed of a warp T, a weft R, and an interlayer binding yarn (not shown). The warp threads T and weft threads R are made of continuous reinforcing fibers. As the reinforcing fiber, an organic fiber or an inorganic fiber may be used, or a different kind of organic fiber, a different kind of inorganic fiber, or a mixed fiber which is a mixture of the organic fiber and the inorganic fiber may be used. Examples of the organic fiber include acrylic fiber, nylon fiber, polyester fiber, aramid fiber, poly-p-phenylene benzobisoxazole fiber, ultrahigh molecular weight polyethylene fiber and the like, and examples of the inorganic fiber include carbon fiber, glass fiber and ceramic fiber. And so on. In this embodiment, the warp T and the weft R are made of carbon fibers.

The L-shaped fiber body 13 is a multi-layer woven fabric formed by connecting a plurality of warp layers 13a as a fiber layer and a plurality of weft layers 13b as a fiber layer in a stacking direction Z with an interlayer binding yarn (not shown). The warp layer 13a is formed by arranging a plurality of warp threads T in parallel with each other, and the weft layer 13b is formed by arranging a plurality of weft threads R in parallel with each other. The plurality of warp threads T and weft threads R are orthogonal to each other. The L-shaped fiber body 13 may be formed by laminating a single-layer woven fabric formed by plain weave, twill weave, or satin weave, and connecting the laminated body with an interlayer binding thread. That is, the weaving structure of the L-shaped fiber body 13 may be any.

The L-shaped fiber body 13 is formed by bending a flat multi-layer woven fabric into an L shape. The "L shape" of the L-shaped fiber body 13 means that the cross section of the L-shaped fiber body 13 along the stacking direction Z is L-shaped. The L-shaped fiber body 13 has a flat plate-shaped base portion 15, a flat plate-shaped flange constituent portion 16 orthogonal to the base portion 15, and a connecting portion 17 connecting the base portion 15 and the flange constituent portion 16. In the L-shaped fiber body 13, the yarn spindle of the weft R extends in a direction connecting the base portion 15 and the flange constituent portion 16. On the other hand, the yarn spindle of the warp yarn T extends in a direction orthogonal to the yarn spindle of the weft yarn R.

As shown in FIG. 2, the base portion 15 includes a first base portion surface 15a facing the base portion 15 of the other L-shaped fiber body 13 on one end surface in the stacking direction Z, and a second base portion on the other end surface in the stacking direction Z. It has a surface 15b. The flange component 16 includes a first flange surface 16a facing the second fiber base material 20 on one end surface in the stacking direction Z, and a second flange surface 16b on the other end surface in the stacking direction Z.

The connecting portion 17 is a portion sandwiched between the flat plate-shaped base portion 15 and the flange constituent portion 16, and has a substantially fan-shaped cross section along the stacking direction Z. The connecting portion 17 includes a first curved surface 17a located between the first base surface 15a of the base 15 and the first flange surface 16a of the flange component 16, and has a flange configuration with the second base surface 15b of the base 15. A second curved surface 17b located between the second flange surface 16b of the portion 16 is provided. The curvatures of the first curved surface 17a and the second curved surface 17b are the same. The arc length of the first curved surface 17a is longer than the arc length of the second curved surface 17b in the cross section along the stacking direction Z.

In the first fiber base material 12, the main body portion 11a is formed from the base portions 15 of the two L-shaped fiber bodies 13. In the main body 11a, the plurality of warp layers 13a and the plurality of weft layers 13b are laminated in the stacking direction Z. Further, the first fiber base material 12 is sandwiched between the first curved surface 17a of one L-shaped fiber body 13 and the first curved surface 17a of the other L-shaped fiber body 13 in the stacking direction Z of the fiber layer. A bifurcated branch portion 18 is provided along the bifurcated portion 18. The branch portion 18 is recessed from the first flange surface 16a of the pair of L-shaped fiber bodies 13.

As shown in FIG. 1, the second fiber base material 20 has a flat plate shape. The second fiber base material 20 is composed of a warp T, a weft R, and an interlayer binding yarn (not shown). The warp threads T and weft threads R are made of reinforcing fibers. As the reinforcing fiber, an organic fiber or an inorganic fiber may be used, or a different kind of organic fiber, a different kind of inorganic fiber, or a mixed fiber which is a mixture of the organic fiber and the inorganic fiber may be used. Examples of the organic fiber include acrylic fiber, nylon fiber, polyester fiber, aramid fiber, poly-p-phenylene benzobisoxazole fiber, ultrahigh molecular weight polyethylene fiber and the like, and examples of the inorganic fiber include carbon fiber, glass fiber and ceramic fiber. And so on. In this embodiment, the warp T and the weft R are made of carbon fibers.

The second fiber base material 20 is a multi-layer woven fabric formed by bonding a plurality of warp layers 20a as a fiber layer and a plurality of weft layers 20b as a fiber layer in the stacking direction Z by an interlayer bonding yarn (not shown). .. The warp layer 20a is formed by arranging a plurality of warp threads T in parallel with each other, and the weft layer 20b is formed by arranging a plurality of weft threads R in parallel with each other. The plurality of warp threads T and weft threads R are orthogonal to each other. The second fiber base material 20 may be configured by laminating a single-layer woven fabric formed by plain weave, twill weave, or satin weave, and bonding the laminated body with an interlayer binding thread. That is, the woven structure of the second fiber base material 20 may be any. In the fiber structure 11, the depth direction is orthogonal to the stacking direction Z of the warp layer 13a and the weft layer 13b in the main body 11a and the stacking direction Z of the warp layer 20a and the weft layer 20b in the second fiber base material 20. Let it be Y. The above-mentioned branch portion 18 extends continuously along the depth direction Y and exists over the entire depth direction Y of the fiber structure 11.

In the second fiber base material 20, the yarn main shaft of the warp yarn T extends in the depth direction Y of the fiber structure 11, and the yarn main shaft of the weft yarn R is in a direction orthogonal to the depth direction Y and the lamination direction Z of the fiber structure 11. It is extending.

As shown in FIG. 2, the second fiber base material 20 is superposed on the flange 11b composed of a pair of flange constituent portions 16. The second fiber base material 20 includes a first surface 20c facing the pair of first flange surfaces 16a on one end surface in the stacking direction Z, and a second surface 20d on the other end surface in the stacking direction Z.

The main body portion 11a of the fiber structure 11 is configured such that the first base portion surfaces 15a face each other and the pair of base portions 15 are integrated. The flange 11b of the fiber structure 11 is formed by integrating the first flange surface 16a of the pair of flange constituent portions 16 with the first surface 20c of the second fiber base material 20 facing each other.

In the fiber structure 11 having the above structure, the amount of fiber per unit volume is defined as the fiber volume content Vf. The higher the fiber volume content Vf, the larger the amount of fibers contained in the unit volume, and the narrower the fibers are. On the other hand, the lower the fiber volume content Vf, the smaller the amount of fibers contained in the unit volume, and the more the fibers are opened. In the present embodiment, the fiber volume content Vf of the fiber structure 11 is 55 to 65%, but the fiber volume content Vf may be appropriately changed according to the purpose of use of the fiber reinforced composite material 10.

In the fiber structure 11, since the second fiber base material 20 is integrated with the first fiber base material 12, the branch portion 18 is covered with the second fiber base material 20. The fiber structure 11 has a gap S defined by covering the branch portion 18 with the second fiber base material 20, and the gap S is filled with the gap filling member 30. The gap S is between the first curved surface 17a of one L-shaped fiber body 13, the first curved surface 17a of the other L-shaped fiber body 13, and the first surface 20c of the second fiber base material 20. It is defined in. Further, the gap S extends over the entire depth direction Y of the fiber structure 11.

As shown in FIG. 3 or 4, the gap filling member 30 is formed of discontinuous fibers H of reinforcing fibers. As the reinforcing fiber, an organic fiber or an inorganic fiber may be used, or a different kind of organic fiber, a different kind of inorganic fiber, or a mixed fiber which is a mixture of the organic fiber and the inorganic fiber may be used. Examples of the organic fiber include acrylic fiber, nylon fiber, polyester fiber, aramid fiber, poly-p-phenylene benzobisoxazole fiber, ultrahigh molecular weight polyethylene fiber and the like, and examples of the inorganic fiber include carbon fiber, glass fiber and ceramic fiber. And so on. In this embodiment, the discontinuous fiber H is made of carbon fiber.

As shown in FIG. 4, the gap filling member 30 includes a twisted yarn 31 of the discontinuous fiber H and a plurality of covering yarns 32 spirally wound around the twisted yarn 31 of the discontinuous fiber H. As the covering yarn 32, fibers made by hot melting are used, for example, nylon fibers. The gap filling member 30 is a fiber bundle in which the lengths of the discontinuous fibers H are aligned in the axial direction of the gap filling member 30. The twisted yarn 31 of the gap filling member 30 is bulkier than a fiber bundle in which a plurality of continuous fibers are aligned. Further, in the gap filling member 30, the length of the discontinuous fiber H is oriented so as to extend in the axial direction of the gap filling member 30.

The axial dimension of the gap filling member 30 preferably has a dimension of 60% or more of the total dimension of the gap S along the depth direction Y. In the present embodiment, the gap filling member 30 has the depth of the gap S. It has dimensions over the entire direction Y. That is, the axial dimension of the gap filling member 30 is the same as the axial dimension of the gap S in the depth direction Y. Further, the amount of the gap filling member 30 to be filled in the gap S is adjusted so that the fiber volume content Vf in the gap S of the fiber structure 11 is equal to or less than the fiber volume content Vf in the portion other than the gap S. Will be done. That is, the fiber volume content Vf indicating the amount of discontinuous fibers H per unit volume in the gap S is equal to or less than the fiber volume content Vf indicating the amount of reinforcing fibers per unit volume in the main body 11a. In the present embodiment, the fiber volume content Vf in the gap S is adjusted to 30 to 55%, but the fiber volume content Vf in the gap S is appropriately changed according to the purpose of use of the fiber reinforced composite material 10. You may.

Then, as shown in FIG. 1, in the fiber-reinforced composite material 10 using the fiber structure 11 having the above configuration as a reinforcing base material, a plurality of gap filling members 30 are filled in the gap S, and the gap S is discontinuous. The amount of fiber H is adjusted so as to have a desired fiber volume content Vf. Further, as shown in FIG. 3, the length of the discontinuous fiber H of the gap filling member 30 is oriented so as to extend in the depth direction Y of the fiber structure 11. Therefore, the periphery of the gap S in the fiber-reinforced composite material 10 is reinforced in the depth direction Y by the filled discontinuous fibers H.

Next, a method for producing the fiber-reinforced composite material 10 using the fiber structure 11 as a reinforcing base material will be described together with its actions.
First, the first fiber base material 12 having a T-shaped cross section and the second fiber base material 20 having a flat plate shape are manufactured. Next, as shown in FIG. 5, a plurality of gap filling members 30 are placed on the branch portion 18 of the first fiber base material 12. At this time, the number of the gap filling members 30 to be placed is adjusted so that the fiber volume content Vf of the gap S to be formed later becomes a desired value. Then, only by placing the gap filling member 30 on the branch portion 18, the processing to the portion of the fiber structure 11 that becomes the gap S is completed later. That is, the work required to reinforce the periphery of the gap S in the fiber-reinforced composite material 10 is completed.

Next, as shown in FIG. 6, the second fiber base material 20 is placed on the pair of first flange surfaces 16a of the first fiber base material 12, and the first flange surface 16a and the first surface of the second fiber base material 20 are placed. Face 20c. Then, the branch portion 18 is covered with the second fiber base material 20, and the gap S filled with the gap filling member 30 is defined between the first fiber base material 12 and the second fiber base material 20. ..

Then, the fiber structure 11 is impregnated with the matrix resin Ma. A resin transfer molding (RTM) method is adopted for this impregnation treatment. Specifically, the fiber structure 11 including the first fiber base material 12, the second fiber base material 20, and the gap filling member 30 is arranged in a cavity of a mold (not shown). The molten matrix resin Ma is injected into the cavity of the mold, and the fiber structure 11 is impregnated with the matrix resin Ma. At this time, the covering yarn 32 is melted by the temperature of the melted matrix resin Ma.

The matrix resin Ma is impregnated between the continuous fibers of the warp T, the weft R, and the interlayer bonding yarn of the fiber structure 11, and is also impregnated between the discontinuous fibers H of the gap filling member 30. After that, the fiber-reinforced composite material 10 is formed by curing the matrix resin Ma.

According to the above embodiment, the following effects can be obtained.
(1) The gap filling member 30 filled in the gap S of the fiber structure 11 is string-shaped because it is a fiber bundle of discontinuous fibers H. Therefore, for example, as compared with the case where the non-woven fabric is arranged in the branch portion 18, it is easier to handle and it is not necessary to shape the branch portion 18 like the non-woven fabric, so that the gap filling member 30 is arranged in the branch portion 18. The work to do is easy.

Then, in the fiber reinforced composite material 10, the periphery of the gap S is reinforced by the discontinuous fiber H. The amount of discontinuous fibers H filled in the gap S can be adjusted to an amount suitable for reinforcement only by adjusting the number of the gap filling members 30 filled in the gap S. Therefore, as compared with the case where, for example, a plurality of types of reinforcing materials are prepared to reinforce the periphery of the gap S, or a reinforcing member following the shape of the gap S is manufactured, the fiber reinforced composite material 10 is used. The work required to reinforce the periphery of the gap S in the above can be easily performed.

(2) The gap filling member 30 is a fiber bundle of discontinuous fibers H. For example, as compared with a fiber bundle in which continuous fibers are aligned, the gaps between the discontinuous fibers H are easily opened, and the matrix resin Ma is easily impregnated. Therefore, in the fiber-reinforced composite material 10 using the fiber structure 11 as a reinforcing base material, the matrix resin Ma sufficiently permeates between the discontinuous fibers H of the gap filling member 30, and a resin-rich portion is formed. This can be suppressed, and the periphery of the gap S in the fiber-reinforced composite material 10 can be reinforced.

(3) The number of gap filling members 30 is adjusted so that the fiber volume content Vf in the gap S is equal to or less than the fiber volume content Vf of the first fiber base material 12 and the second fiber base material 20. Therefore, the fiber volume content Vf in the gap S does not become too high, and it is possible to prevent the gap filling member 30 in the gap S from being easily impregnated with the matrix resin Ma during the production of the fiber reinforced composite material 10.

(4) The axial dimension of the gap filling member 30 is 60% or more of the dimension of the gap S in the depth direction Y. Therefore, the discontinuous fibers H of the gap filling member 30 are oriented so as to extend in the depth direction Y, and in the fiber reinforced composite material 10, the gap filling member 30 can secure the strength in the depth direction Y in the gap S.

(5) The gap filling member 30 is formed by holding a twisted yarn 31 made of discontinuous fiber H with a covering yarn 32. Therefore, when the gap filling member 30 is arranged in the branch portion 18, it is possible to prevent the discontinuous fibers H from being scattered, and the gap filling member 30 can be easily arranged in the branch portion 18.

(6) The gap filling member 30 arranged at the branch portion 18 is string-shaped. Therefore, the branch portion 18 is arranged along the axial direction of the gap filling member 30 in the depth direction Y of the branch portion 18. Therefore, it is easy to arrange the gap filling member 30 even in a narrow portion such as the branch portion 18 of the first fiber base material 12.

(7) The gap filling member 30 is a fiber bundle in which the lengths of the discontinuous fibers H are aligned so as to extend in the axial direction of the gap filling member 30, and is different from the non-woven fabric in which the orientation of the discontinuous fibers H is random. Therefore, during the production of the fiber-reinforced composite material 10, it is possible to prevent the gap filling member 30 in the gap S from flowing out from the gap S due to the injection pressure of the matrix resin Ma.

(8) The size of the gap S of the fiber structure 11 differs depending on the size and shape of the fiber reinforced composite material 10. The gap filling member 30 has a string shape, and the gap filling member 30 can be filled according to the size and shape of the gap S simply by adjusting the number of the gap filling members 30. Therefore, it is not necessary to manufacture a filling member that matches the size and shape of the gap S, and the work for reinforcing the periphery of the gap S becomes easy.

(9) Since the fiber volume content Vf of the gap filling member 30 can be grasped in advance, it is easy to adjust the fiber volume content Vf in the gap S by adjusting the number of the gap filling members 30.
(10) The gap filling member 30 is a fiber bundle of discontinuous fibers H and is bulky. Therefore, when the gap filling member 30 is arranged in the branch portion 18, even if the gap filling members 30 are stacked, the gaps between the gap filling members 30 and the discontinuous fibers H of each gap filling member 30 are opened. The state can be secured. Therefore, the gap filling member 30 can also be impregnated with the matrix resin Ma.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
○ As shown in FIG. 7, the gap filling member 40 is wound around a core yarn 41 made of continuous fibers extending in the entire axial direction of the gap filling member 40, a coating layer 42 covering the core yarn 41, and a coating layer 42. The cover ring thread 43 may be provided. The core yarn 41 is a twisted yarn formed by twisting continuous fibers. The coating layer 42 is a twisted yarn made of discontinuous fibers H.

In this configuration, since the gap filling member 40 includes the core thread 41 made of continuous fiber, it is easy to maintain the shape of the gap filling member 40 having straightness by the core thread 41, and the branch portion 18 is provided. It is easy to arrange the gap filling member 40.

○ The fiber structure 11 may be formed by integrally forming the first fiber base material 12 having a T-shaped cross section and the second fiber base material 20 having a T-shaped cross section. In this case, the first fiber base material 12 and The second fiber base material 20 is integrated with the branch portions 18 facing each other, and the gap S has a substantially quadrangular cross section along the stacking direction Z.

○ The total length of the gap filling member 30 may be shorter than the dimension of the branch portion 18 in the depth direction Y. In this case, the gap filling member 30 is connected in the thread spindle direction, and the gap filling member 30 is arranged over the entire depth direction Y of the branch portion 18.

○ The total length of the gap filling member 30 may be longer than the dimension of the branch portion 18 in the depth direction Y. In this case, the portion protruding from the branch portion 18 in the depth direction Y is cut off, and the gap filling member 30 is arranged over the entire depth direction Y of the branch portion 18.

The gap filling member 30 may not include the covering yarn 32 and may be configured by simply twisting the discontinuous fibers H.
○ The gap filling member 30 may be a non-twisted yarn of non-continuous fiber H.

○ In the embodiment, the branch portion 18 is formed by integrating a pair of L-shaped fiber bodies 13, but a single fiber body may be branched in a bifurcated shape to form the branch portion 18.
○ Although a thermosetting resin was used as the matrix resin Ma, other types of resins may be used.

○ The matrix material may be ceramic other than the matrix resin Ma.
○ In the first fiber base material 12 and the second fiber base material 20, the number of fiber layers to be laminated may be arbitrarily changed.

○ The second fiber base material 20 may be composed of one single-layer woven fabric formed by plain weave, twill weave, and satin weave.

H Non-continuous fiber Ma Matrix resin as matrix material S Gap Y Depth direction Z Lamination direction Vf Fiber volume content 10 Fiber reinforced composite material 11 Fiber structure 11a Main body 12 First

fiber base material

13a, 20a Warp as

fiber layer Layers

13b, 20b Weft layer as fiber layer 18 Branch part 20 Second

fiber base material

30, 40 Gap filling member 41 Core thread 42 Coating layer

Claims

The fiber structure of a fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material.
A first fiber base material having a main body portion in which a plurality of fiber layers of reinforcing fibers are laminated and a branch portion in which the main body portion is bifurcated along the laminating direction of the fiber layers.
A second fiber base material that covers the branch portion and is integrated with the first fiber base material is provided.
A gap filling member for filling the gap defined by the branch portion and the second fiber base material is provided.
The gap filling member is a fiber structure characterized by being a fiber bundle of discontinuous fibers.
The second fiber base material has a plurality of laminated fiber layers of reinforcing fibers, and has a direction orthogonal to the laminating direction of the fiber layers in the second fiber base material and the laminating direction of the fiber layers in the main body portion. In the depth direction, the branch portion extends continuously along the depth direction, the gap extends over the entire depth direction of the fiber structure, and the axial dimension of the gap filling member is The fiber structure according to claim 1, which is 60% or more of the size of the gap in the depth direction.
Claim 1 or claim 2 that the fiber volume content indicating the amount of the discontinuous fibers per unit volume of the gap is equal to or less than the fiber volume content indicating the amount of the reinforcing fibers per unit volume in the main body. The fibrous structure described in.
Any one of claims 1 to 3, wherein the gap filling member includes a core yarn made of continuous fibers extending in the entire axial direction of the gap filling member and a coating layer made of discontinuous fibers covering the core yarn. The fiber structure according to one item.
A fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material, wherein the fiber structure is the fiber structure according to any one of claims 1 to 4. Material.