JP2022119368A - Fiber structure and fiber-reinforced composite material - Google Patents

Abstract

To provide a fiber structure and a fiber-reinforced composite material, which can suppress reduction in mechanical property at a bent part.SOLUTION: A fiber structure 20 has a non-binding yarn 50 having a cut end 50a formed by cutting an interlaminar binding yarn 40. A first flat plate part 21 and a second flat plate part 23 of the fiber structure 20 have a portion bonded with the interlaminar binding yarn 40 in lamination direction Z. A bent part 22 of the fiber structure 20 has a portion on which the non-binding yarn 50 is disposed.SELECTED DRAWING: Figure 2

Description

The present invention relates to fiber structures and fiber-reinforced composites.

Fiber-reinforced composite materials are used as lightweight and high-strength materials. A fiber-reinforced composite material is formed by compounding a fiber structure made of reinforcing fibers with a matrix resin. Fiber-reinforced composites have improved mechanical properties compared to the resin itself. For this reason, fiber reinforced composites are preferred as structural components.

Some fiber-reinforced composite materials have a flat portion and a bent portion. A bent portion is a portion where the fiber structure is bent along an imaginary axis. At the bending portion, the fiber bundle that intersects the imaginary axis is bent. As the fiber bundle is bent, wrinkles are formed in the fiber structure. If the fibrous structure is impregnated with the matrix resin while wrinkled, the strength of the wrinkled portion of the resulting fiber-reinforced composite material will be reduced.

In order to suppress the decrease in strength of the fiber-reinforced composite material, wrinkles in the bent portion are reduced or eliminated. For example, in Japanese Patent Laid-Open No. 2002-200012, wrinkles generated in the bent portion are eliminated. The fabric base material of Patent Document 1 includes a first portion and a second portion having different yarn densities. The density of the first portion is lower than the density of the second portion. For this reason, in the first region, at least one of the first yarn and the second yarn has a wider spacing between the yarns than in the second region. In addition, since the range in which the yarn is shifted is wider in the first portion than in the second portion, even if wrinkles occur in the first portion when the woven fabric base material is shaped to form a bent portion, the first portion At least one of the first yarn and the second yarn is shifted to eliminate wrinkles.

JP 2013-112899 A

However, if the density of the fiber bundles at the bent portion is lower than the density of the fiber bundles at the flat portion as in Patent Document 1, the amount of the fiber bundles at the bent portion becomes smaller than the amount of the fiber bundles at the flat portion. The mechanical properties of the bent portion are degraded.

A fiber structure for solving the above problems includes a first fiber layer in which a plurality of first fiber bundles are arranged in a first arrangement direction and a second fiber layer in which a plurality of second fiber bundles are arranged in a second arrangement direction. a laminate in which two fiber layers are laminated, the first arrangement direction and the second arrangement direction are orthogonal, and the fiber bundles of the fiber layers at both ends in the lamination direction are laminated in the same arrangement direction; and an interlayer binding yarn that binds the body in the stacking direction, the flat plate portion where the first fiber bundle and the second fiber bundle extend linearly, and the fiber layers located at both ends in the stacking direction. A fiber structure having a bent portion in which a fiber bundle in an arrangement direction is bent, wherein the first fiber bundle extends continuously between both ends of the fiber structure in the second arrangement direction, and the second The fiber bundle extends continuously between both ends of the fiber structure in the first arrangement direction and has unbound yarns having cut ends formed by cutting the interlayer bound yarns, The gist is that the flat plate portion has a portion bonded in the lamination direction by the interlayer bonding yarn, and the bent portion has a portion where the non-bonding yarn is arranged.

According to this, the inter-layer binding yarn is cut at the bent portion where the non-binding yarn is arranged, and the binding force by the inter-layer binding yarn is weakened. When the fiber bundle is bent to form the bent portion, a force for bending the fiber bundle is applied to the bent fiber bundle. At this time, since the binding force in the lamination direction of the interlayer binding yarn is weakened, the fiber bundle that receives the force for bending can move under the force. Therefore, it is possible to suppress bending of the fiber bundle due to bending force, such as when the fiber bundle is bent while being bound by the interlayer binding yarn. As a result, the fiber bundle that is bent at the bent portion is smoothly bent along the bent portion. Therefore, it is possible to suppress the occurrence of wrinkles at the bent portion of the fiber structure.

As described above, by adopting the non-bonded yarn obtained by cutting the interlayer bonded yarn, the occurrence of wrinkles in the bent portion is suppressed. also does not reduce the density of the fiber bundles. As a result, it is possible to suppress the occurrence of wrinkles in the bent portion while suppressing deterioration of the mechanical properties of the bent portion.

With regard to the fiber structure, the bent portion may have a protruded portion of the cut end on at least one of the fiber layers on both ends in the stacking direction.
When a fiber structure in which the cut ends are embedded in the fiber layer is impregnated with a matrix resin to form a fiber-reinforced composite material, the cut ends do not protrude into the matrix resin, so a portion consisting only of the matrix resin is likely to be formed. . However, since the cut ends protrude above the fiber layer, it is possible to reduce the portion of only the matrix resin, thereby suppressing a decrease in the strength of the fiber-reinforced composite material using the fiber structure.

With respect to the fiber structure, the cut ends may be located on the fiber layer located inside the bent portion among the fiber layers on both ends in the stacking direction.
According to this, the cut end portion is positioned on the fiber layer positioned inside the bent portion, so the interlayer binding yarn is cut inside the bent portion. When the laminate is bound by the interlayer binding yarn, the fiber bundles located inside the bent portion are more likely to bend than the fiber bundles located outside. However, since the interlayer binding yarn is cut inside the bent portion, it is possible to suppress bending of the fiber bundle inside the bent portion.

For the fibrous structure, the cut ends may line up along the crease of the bend.
According to this, the fiber bundle is bent most along the crease of the bent portion. Since the binding force of the interlayer binding yarn is weakened at the most bendable portion of the fiber bundle, bending of the fiber bundle can be suppressed.

For the fibrous structure, the non-bonded yarns may be arranged over the entire area of the bend.
According to this, since the binding force of the interlayer binding yarn is weakened for all the fiber bundles bent at the bent portion, it is possible to further suppress the occurrence of wrinkles at the bent portion.

A fiber-reinforced composite material for solving the above problems is a fiber-reinforced composite material formed by impregnating a fiber structure with a matrix resin, and the fiber structure is any one of claims 1 to 5. The gist is that it is the fiber structure according to claim 1.

According to this, the inter-layer binding yarn is cut at the bent portion where the non-binding yarn is arranged, and the binding force by the inter-layer binding yarn is weakened. When the fiber bundle is bent to form the bent portion, a force for bending the fiber bundle is applied to the bent fiber bundle. At this time, since the binding force in the lamination direction of the interlayer binding yarn is weakened, the fiber bundle that receives the force for bending can move under the force. Therefore, it is possible to suppress bending of the fiber bundle due to bending force, such as when the fiber bundle is bent while being bound by the interlayer binding yarn. As a result, the fiber bundle that is bent at the bent portion is smoothly bent along the bent portion. Therefore, it is possible to suppress the occurrence of wrinkles at the bent portion of the fiber structure.

As described above, by adopting the non-bonded yarn obtained by cutting the interlayer bonded yarn, the occurrence of wrinkles in the bent portion is suppressed. also does not reduce the density of the fiber bundles. As a result, it is possible to suppress the occurrence of wrinkles in the bent portion while suppressing the deterioration of the mechanical properties of the bent portion, and in the fiber-reinforced composite material, it is possible to suppress the decrease in strength caused by the wrinkles of the fiber structure.

ADVANTAGE OF THE INVENTION According to this invention, the deterioration of the mechanical characteristic of a bending part can be suppressed.

The perspective view which shows a fiber reinforced composite material typically. Sectional drawing which shows a bending part and a flat plate part typically. The top view which shows a fiber structure. The perspective view which shows a 1st flat plate part. (a) is an enlarged cross-sectional view showing a first flat plate portion, and (b) is an enlarged cross-sectional view showing a non-bonded yarn. FIG. 4 is a partial plan view showing the fiber structure before forming a bent portion; The figure which shows the bending part of a comparative example typically. The perspective view which shows the state which cut|disconnected the interlayer binding yarn. FIG. 4 is an enlarged cross-sectional view showing another example of non-bonded yarn;

An embodiment embodying a fiber structure and a fiber-reinforced composite material will be described below with reference to FIGS. 1 to 8. FIG.
As shown in FIG. 1, the fiber-reinforced composite material 10 is formed by impregnating a fiber structure 20 with a matrix resin Ma. The fiber structure 20 is the reinforcing base material of the fiber-reinforced composite material 10 . Epoxy resin, which is a thermosetting resin, is used as the matrix resin Ma. The matrix resin Ma may not be an epoxy resin, but may be a thermosetting resin such as vinyl ester resin, unsaturated polyester resin, phenol resin, polyamide, polybutylene terephthalate, polycarbonate, polyethylene, Thermoplastic resins such as polypropylene, polyimide resin, and ABS resin may be used.

Assuming that the fiber-reinforced composite material 10 is placed on a horizontal plane, the direction of gravity is indicated by the Z-axis, and the directions along the horizontal plane are indicated by the X-axis and the Y-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. In the following description, the direction parallel to the Z-axis is also called the stacking direction Z, and the direction parallel to the X-axis is also called the first arrangement direction X. A direction parallel to the Y-axis is also referred to as a second arrangement direction Y. As shown in FIG.

The fiber-reinforced composite material 10 has a first composite flat plate portion 11 , a composite bent portion 12 indicated by dot hatching, and a second composite flat plate portion 13 . The first composite flat plate portion 11, the composite bent portion 12, and the second composite flat plate portion 13 are continuous in the second arrangement direction Y. As shown in FIG.

Looking at the first composite flat plate portion 11 from the outside in the stacking direction Z, the first composite flat plate portion 11 has a rectangular shape. 13 is rectangular.

The compound bending portion 12 has a bending center on an imaginary axis line M that passes through the center of curvature of the compound bending portion 12 and extends in parallel with the X axis. It can be said that the imaginary axis M extends in the first arrangement direction X. As shown in FIG.
As shown in FIGS. 2 and 3 , the fiber structure 20 has a laminate 30 , interlayer binding yarns 40 and non-binding yarns 50 .

The fiber structure 20 includes a first flat plate portion 21 that serves as a reinforcing base material for the first composite flat plate portion 11, a bent portion 22 that serves as a reinforcing base material for the composite bent portion 12, and a reinforcing base material for the second composite flat plate portion 13. and a second flat plate portion 23 that becomes The first flat plate portion 21, the bent portion 22, and the second flat plate portion 23 are continuous in the second arrangement direction Y. As shown in FIG.

The fiber structure 20 has a first surface 201 on the first side in the stacking direction Z and a second surface 202 on the second side in the stacking direction Z. As shown in FIG. The fiber structure 20 is folded in such a manner that a crease line N of a valley fold is formed on the first surface 201 . The side on which the fold line N is positioned is the inside of the bent portion 22 . Therefore, the bent portion 22 is bent with the first surface 201 side facing inward.

The fiber structure 20 has a first side face 20a on a first end face in the first arrangement direction X, and a second side face 20b on a second end face in the first arrangement direction X. As shown in FIG. The fiber structure 20 has a third side face 20c on the first end face in the second arrangement direction Y, and a fourth side face 20d on the second end face in the second arrangement direction Y. As shown in FIG.

As shown in FIGS. 2, 3 and 4, the laminate 30 has a plurality of warp layers 31 as first fiber layers and a plurality of weft layers 32 as second fiber layers. The plurality of warp layers 31 and the plurality of weft layers 32 are alternately laminated. The plurality of warp layers 31 and the plurality of weft layers 32 may not be alternately laminated.

The direction in which the warp layer 31 and the weft layer 32 are laminated is the lamination direction Z. As shown in FIG. Warp layers 31 are arranged at both ends of the laminate 30 in the lamination direction Z. As shown in FIG. Therefore, warp yarns 34 are arranged at both ends of the laminate 30 in the lamination direction Z. As shown in FIG. Therefore, at both ends of the laminate 30 in the lamination direction Z, the warp yarns 34 are arranged in the same arrangement direction.

Each warp layer 31 is formed by arranging a plurality of warp yarns 34 as first fiber bundles in the first arrangement direction X. As shown in FIG. A plurality of warp threads 34 are parallel to each other. All warp threads 34 have the same length.

Each weft layer 32 is formed by arranging a plurality of wefts 35 as second fiber bundles in the second arrangement direction Y. As shown in FIG. A plurality of weft threads 35 are parallel to each other. All weft threads 35 have the same length.

The warp layers 31 and the weft layers 32 are alternately laminated such that the first arrangement direction X and the second arrangement direction Y are orthogonal to each other. The laminate 30 has a biaxial orientation with the first arrangement direction X as one axis and the second arrangement direction Y as two axes.

The warp yarns 34 and the weft yarns 35 are fiber bundles formed by bundling a plurality of reinforcing fibers. The reinforcing fibers may be either continuous fibers or discontinuous fibers. Organic fibers or inorganic fibers are used as the reinforcing fibers. Examples of organic fibers include aramid fibers, poly-p-phenylenebenzobisoxazole fibers, and ultra-high molecular weight polyethylene fibers. Examples of inorganic fibers include carbon fibers, glass fibers, and ceramic fibers.

In the first flat plate portion 21 and the second flat plate portion 23, each warp 34 of each warp layer 31 extends linearly in the second arrangement direction Y. As shown in FIG. In the first flat plate portion 21 and the second flat plate portion 23, each weft 35 of each weft layer 32 extends linearly in the first arrangement direction X. As shown in FIG. In the bending portion 22, each warp 34 of each warp layer 31 is smoothly bent, while each weft 35 extends linearly in the first arrangement direction X. As shown in FIG.

At both ends of the fiber structure 20 in the first arrangement direction X, tip surfaces of the wefts 35 are exposed. The weft yarn 35 extends continuously between both ends of the fiber structure 20 in the first arrangement direction X. As shown in FIG. At both ends of the fiber structure 20 in the second arrangement direction Y, the tip surfaces of the warp yarns 34 are exposed. there is That is, the warp yarns 34 and the weft yarns 35, which are in-plane yarns of the fiber structure 20, are not cut inside the fiber structure 20. As shown in FIG.

The side edges of the warp yarns 34 positioned at the first end in the first arrangement direction X are exposed on the first side face 20a. Further, tip surfaces of the weft yarns 35 located at the first end in the first arrangement direction X are exposed on the first side surface 20a. On the first side surface 20a, the side edges of the warp yarns 34 and the tip surfaces of the weft yarns 35 exposed on the first side surface 20a are laminated along the vertical plane.

The side edges of the warp yarns 34 positioned at the second end in the first arrangement direction X are exposed on the second side surface 20b. Further, tip surfaces of the wefts 35 positioned at the second end in the first arrangement direction X are exposed on the second side surface 20b. On the second side surface 20b, the side edges of the warp yarns 34 and the tip surfaces of the weft yarns 35 exposed on the second side surface 20b are laminated along the vertical plane.

The tip surfaces of the warp yarns 34 located at the first end in the second arrangement direction Y are exposed on the third side surface 20c. Further, the side edge of the weft 35 positioned at the first end in the second arrangement direction Y is exposed on the third side surface 20c. On the third side surface 20c, the tip surfaces of the warp yarns 34 and the side edges of the weft yarns 35 exposed on the third side surface 20c are laminated along the vertical plane.

The tip surfaces of the warp yarns 34 positioned at the second end in the second arrangement direction Y are exposed on the fourth side surface 20d. Further, the side edge of the weft 35 located at the second end in the second arrangement direction Y is exposed on the fourth side surface 20d.

On the fourth side surface 20d, the warp yarns 34 arranged in the stacking direction Z from the first surface 201 to the second surface 202 in the stacking direction Z have different tip positions. That is, the warp yarns 34 aligned in the stacking direction Z are inclined so that the tip surfaces of the warp yarns 34 are lowered from the first surface 201 toward the second surface 202 .

Further, on the fourth side surface 20d, the positions of the side edges of the wefts 35 arranged in the stacking direction Z from the first surface 201 to the second surface 202 in the stacking direction Z are different. That is, the wefts 35 aligned in the stacking direction Z are inclined so that the side edges of the wefts 35 are lowered from the first surface 201 toward the second surface 202 . Therefore, on the fourth side surface 20d, the warp yarns 34 and the weft yarns 35 arranged in the stacking direction Z are not aligned on the horizontal plane, but are stacked on an inclined plane with respect to the horizontal plane.

All warp threads 34 have the same length. Therefore, when the tip surfaces of the first ends of the warp yarns 34 are aligned on the vertical plane on the third side surface 20c, the second ends of the warp yarns 34 are bent according to the path difference between the inner and outer sides of the bent portion 22. The position of the tip surface located at is shifted.

As shown in FIGS. 3, 4, and 5A, the interlayer binding yarn 40 binds the warp layers 31 and the weft layers 32 of the first flat plate portion 21 in the stacking direction Z. As shown in FIGS. Further, the interlayer binding yarn 40 binds the warp layers 31 and the weft layers 32 of the second flat plate portion 23 in the stacking direction Z. As shown in FIG. The interlayer binding thread 40 penetrates the first flat plate portion 21 and the second flat plate portion 23 of the laminate 30 in the lamination direction Z. As shown in FIG. Therefore, the entirety of the first flat plate portion 21 and the second flat plate portion 23 is a portion joined in the stacking direction Z by the interlayer binding yarn 40 .

The interlayer binding yarns 40 are hooked on the warp yarns 34 of the warp layer 31 located on the first surface 201, and the warp yarns 34 of the warp layer 31 located on the second surface 202, which are located on the first surface 201. The warp yarns 34 adjacent to the warp yarns 34 in the first arrangement direction X are hooked. The interlayer binding yarn 40 extends in the first arrangement direction X on both end faces in the lamination direction Z while penetrating the laminate 30 in the lamination direction Z. As shown in FIG.

The interlayer binding yarns 40 are hooked on the warp yarns 34 over the entirety of the first arrangement direction X of the first flat plate portion 21 and the second flat plate portion 23 . A plurality of interlayer binding yarns 40 are provided in the second arrangement direction Y of the first flat plate portion 21 and the second flat plate portion 23 .

As shown in FIGS. 4, 5(b) and 6, the non-bonded yarns 50 are present over the entire area of the bent portion 22. As shown in FIGS. The unbound yarns 50 are formed by binding the flat laminate 30 with the interlayer binding yarns 40 in the lamination direction Z, and then cutting the interlayer binding yarns 40 existing in the area to be the bent portion 22 on the warp layer 31. be done. The unbound yarn 50 exists over the entire first arrangement direction X of the bent portion 22 . A plurality of non-binding yarns 50 are provided in the second arrangement direction Y of the bent portion 22 .

The inter-layer binding yarn 40 is cut at both ends in the stacking direction Z of the interlayer binding yarn 40 . That is, the unbound yarns 50 are formed by cutting the interlayer binding yarns 40 on the warp layers 31 positioned inside and outside the bent portion 22 among the warp layers 31 on both ends in the stacking direction Z. As shown in FIG. Specifically, the inter-layer binding yarns 40 that become the non-binding yarns 50 are formed by cutting a portion that hangs over the warp yarns 34 on the first surface 201 and a portion that hangs over the warp yarns 34 on the second surface 202. there is Therefore, the unbound yarn 50 penetrates the entire stack 30 in the stacking direction Z. As shown in FIG.

The non-bonded yarn 50 has a cut end portion 50a formed by cutting the interlayer bonded yarn 40 . The cut end portion 50a is the end portion of the unbound thread 50 including the cut surface, and is a portion having a certain length. On the first surface 201 of the bent portion 22, cut ends 50a formed by cutting the interlayer binding yarns 40 hooked on the warp yarns 34 are exposed along the warp yarns 34. . Therefore, two cut ends 50a are spaced apart from each other in the first arrangement direction X so as to sandwich the warp 34 therebetween. Further, each cut end portion 50a of the first surface 201 protrudes in the stacking direction Z from the surface of the warp yarn 34 on which the interlayer binding yarn 40 is hooked. That is, each cut end portion 50 a protrudes beyond the surface of the warp yarns 34 on the warp yarn layer 31 forming the first surface 201 .

On the second surface 202 of the bent portion 22, the cut ends 50a formed by cutting the interlayer binding yarns 40 hooked to the warp yarns 34 are exposed along the warp yarns 34. . Therefore, two cut ends 50a are spaced apart from each other in the first arrangement direction X so as to sandwich the warp 34 therebetween. Further, each cut end portion 50a of the second surface 202 protrudes in the stacking direction Z from the surface of the warp yarn 34 on which the interlayer binding yarn 40 is hooked. That is, each cut end portion 50 a protrudes beyond the surface of the warp yarns 34 on the warp yarn layer 31 forming the second surface 202 .

On the first surface 201 and the second surface 202, the cut ends 50a of the unbound yarns 50 are exposed along the creases N of the bent portions 22. As shown in FIG.
Therefore, the bent portion 22 is a portion where the unbound yarns 50 are arranged over the entire area of the bent portion 22 . The bent portion 22 has, over the entire area of the bent portion 22, portions where the cut ends 50a protrude from the warp yarns 34 of the warp layers 31 on the warp layers 31 at both ends in the stacking direction Z. As shown in FIG.

Next, the action of the fiber structure 20 will be described.
FIG. 7 shows a fibrous structure 60 of a comparative example. In the fiber structure 60 of the comparative example, the bent portions 22 are also bound in the stacking direction Z by the interlayer binding yarns 40 . Therefore, in the fiber structure 60 of the comparative example, the warp yarns 34 are bent to form the bent portion 22, and when a force for bending the warp yarns 34 is applied to the warp yarns 34, the warp yarns 34 are bent. It's closed.

However, as shown in FIG. 2, the binding strength of the inter-layer binding yarn 40 is weakened at the bent portion 22 of the fiber structure 20 . Therefore, the warp yarns 34 can move in all directions in the entire bending portion 22, and as a result, the warp yarns are smoothly bent. Therefore, wrinkles due to bending of the warp yarns 34 are suppressed from occurring on the first surface 201 and the second surface 202 of the bent portion 22 .

Next, a method for manufacturing the fiber structure 20 will be described.
First, a plurality of warp layers 31 and a plurality of weft layers 32 are laminated to manufacture a flat laminate 30 .

Next, as shown in FIG. 4, the laminate 30 is bound in the lamination direction Z with an interlayer binding yarn 40 .
Next, as shown in FIG. 8, all of the interlayer binding yarns 40 located in the regions to be the bent portions 22 of the laminate 30 are combined with the warp yarns of the warp layers 31 located at both ends of the laminate 30 in the lamination direction Z. Cut on 34 to form a non-bonded thread 50 . As a result, the cut ends 50 a are exposed on the first surface 201 and the second surface 202 , and the cut ends 50 a project from the warp layer 31 .

Next, the laminate 30 is shaped to form the first flat plate portion 21 , the bent portion 22 and the second flat plate portion 23 . When forming the bent portion 22, the warp yarns 34 are also bent, but since there is no binding by the interlayer binding yarns 40, the warp yarns 34 move without bending.

As a result, a fiber structure 20 having bent portions 22 is manufactured.
When the fiber structure 20 is impregnated with the matrix resin Ma, the first flat plate portion 21, the bent portion 22, and the second flat plate portion 23 are impregnated with the matrix resin Ma. A first composite flat plate portion 11 having the first flat plate portion 21 as the reinforcing base material, a composite bending portion 12 having the bending portion 22 as the reinforcing base material, and a second composite flat plate portion having the second flat plate portion 23 as the reinforcing base material. 13 are formed, and the fiber reinforced composite material 10 is manufactured.

Both ends of the interlayer binding yarn 40 are positioned at both ends in the stacking direction Z of the first composite flat plate portion 11 and the second composite plate portion 13, and cut ends 50a are located at both ends in the stacking direction Z of the composite bent portion 12. positioned.

According to the above embodiment, the following effects can be obtained.
(1) A non-bonded yarn 50 is arranged in the bent portion 22 of the fiber structure 20 . Therefore, in the bent portion 22, the binding force in the stacking direction Z by the interlayer binding yarn 40 is weakened. Therefore, the warp yarns 34 bent at the bent portion 22 are suppressed from being bent due to the binding of the interlayer binding yarns 40 and are smoothly bent along the bent portion 22 . The fiber structure 20 employs the non-bonded yarns 50 to suppress the occurrence of wrinkles in the bent portion 22. In order to suppress the occurrence of wrinkles, the warp yarns 34 and the warp yarns 34 and The density of the weft yarn 35 is not reduced. As a result, it is possible to suppress the occurrence of wrinkles in the bent portion 22 while suppressing deterioration of the mechanical properties of the bent portion 22 . Furthermore, in the fiber-reinforced composite material 10 in which the fiber structure 20 is impregnated with the matrix resin Ma, the decrease in strength caused by the wrinkles of the fiber structure 20 can be suppressed.

(2) The cut ends 50 a of the unbound yarns 50 protrude in the stacking direction Z from the warp yarns 34 of the warp layers 31 forming the first surface 201 and the second surface 202 of the bent portion 22 . That is, the non-bonded yarn 50 is formed by cutting the interlayer bonded yarn 40 on the first surface 201 and the second surface 202 of the bent portion 22 . Therefore, even if the interlayer binding yarn 40 is cut, the warp yarn 34 and the weft yarn 35, which are in-plane yarns, are not cut, and the warp yarn 34 extends continuously between both ends in the second arrangement direction Y, and the weft yarn 35 extends continuously between both ends in the first arrangement direction X. As shown in FIG. Therefore, the occurrence of wrinkles can be suppressed without reducing the strength of the fiber structure 20 due to the cutting of the warp yarns 34 and the weft yarns 35 .

(3) When manufacturing the bent portion 22 by bending the flat laminate 30 , the inter-layer binding yarns 40 are cut to form the non-bonding yarns 50 before bending the laminate 30 . Therefore, when the laminate 30 is bent, the warp yarns 34 are easily moved, and bending of the warp yarns 34 can be suppressed.

(4) It is assumed that the cut end portion 50 a is inserted into the warp layer 31 . In this case, in the obtained fiber-reinforced composite material, since the cut ends 50a do not protrude above the warp layer 31, a portion consisting only of the matrix resin Ma is likely to be formed. However, in the present embodiment, since the cut end portion 50a protrudes into the matrix resin Ma, the portion of only the matrix resin Ma can be reduced, and the decrease in strength of the fiber-reinforced composite material 10 can be suppressed.

(5) The non-binding threads 50 are arranged over the entire area of the bent portion 22 . That is, in the bent portion 22, there is no portion where the interlayer binding yarn 40 is bound in the stacking direction Z. As shown in FIG. Therefore, when manufacturing the bent portion 22 , bending of all the warp yarns 34 that are bent is suppressed, and the occurrence of wrinkles in the bent portion 22 of the fiber structure 20 can be further suppressed.

(6) The cut ends 50 a of the unbound yarn 50 are present on both the first surface 201 and the second surface 202 of the bent portion 22 . That is, the non-bonded yarns 50 are formed by cutting the interlayer bonded yarns 40 on the warp layers 31 positioned at both ends in the stacking direction Z. As shown in FIG. Therefore, bending of the warp yarns 34 is suppressed in the entire stacking direction Z. As shown in FIG.

(7) The cut ends 50a of the unbound yarns 50 are arranged along the fold line N of the bent portion 22 and arranged in the first arrangement direction X so as to be parallel to the imaginary axis M of the bent portion 22 . When forming the bend 22 , the warp yarns 34 are bent most along the fold line N of the bend 22 . Since the binding force of the interlayer binding yarns 40 is weakened at the locations where the warp yarns 34 are most bent, bending of the warp yarns 34 can be suppressed.

(8) In order to suppress the occurrence of wrinkles in the bent portion 22, for example, it is conceivable to cut the warp 34 and the weft 35, but the warp 34 and the weft 35 need to be cut within the laminate 30. Cutting work is troublesome. On the other hand, since it is easy to cut the inter-layer binding yarns 40 on the warp layers 31 located at both ends of the laminate 30 in the lamination direction Z to form unbound yarns 50, the fiber structure having the unbound yarns 50 It can be said that the body 20 has high productivity.

Also, in order to suppress the occurrence of wrinkles in the bent portion 22, it is conceivable to change the weave structure of the fiber structure 20, for example, to reduce the weave density. It can be said that cutting the interlayer binding yarn 40 is easier, and the productivity of the fiber structure 20 is high.

In addition, this embodiment can be changed and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
(circle) the unbound thread 50 does not need to be arranged in the whole area|region of the bending part 22. As shown in FIG. For example, the bent portion 22 may have a part where the non-bonded yarn 50 is arranged and another part where the interlayer bound yarn 40 is arranged.

(circle) the imaginary axis line M of the bending part 22 may extend obliquely with respect to the warp yarns 34; In this case, the cut ends 50a of the unbound yarns 50 are preferably arranged along an imaginary line parallel to the imaginary axis M. In this case, the inter-layer binding thread 40 lined up along the imaginary line parallel to the imaginary axis M is cut.

O The unbound thread 50 may exist in at least one region of the first flat plate portion 21 and the second flat plate portion 23 . However, the first flat plate portion 21 and the second flat plate portion 23 must be bound in the stacking direction Z by the interlayer binding thread 40 .

○ As shown in FIG. 9, even if the cut ends 50a of the unbound yarns 50 are positioned only on the warp layers 31 positioned inside the bent portion 22 among the warp layers 31 on both ends in the stacking direction Z, good. That is, the unbound yarns 50 may be formed by cutting the interlayer binding yarns 40 on the warp layers 31 positioned inside the bent portion 22 among the warp layers 31 on both ends in the stacking direction Z. In this case, among the warp layers 31 on both ends in the stacking direction Z, the interlayer binding yarns 40 are not cut on the side of the warp layers 31 positioned outside the bent portion 22 .

In this configuration, when the laminate 30 is bound by the interlayer binding yarns 40, the warp yarns 34 located inside the bent portion 22 are more likely to bend than the warp yarns 34 located outside. However, since the inter-layer binding yarns 40 are cut inside the bent portion 22 to form the non-bonded yarns 50, bending of the warp yarns 34 inside the bent portion 22 can be suppressed.

The cut ends 50 a may protrude from the warp yarns 34 of the warp yarn layer 31 positioned inside the bent portion 22 or may enter the warp yarn layer 31 .
O When the inter-layer binding yarns 40 are cut to form the non-bonded yarns 50, the inter-layer binding yarns 40 may be cut inside the warp layers 31 at both ends in the stacking direction Z. In this case, part of the cut ends 50a of the non-binding yarns 50 enter the warp layer 31. As shown in FIG.

○ When forming the bent portion 22 , the cut end portion 50 a may enter the warp layer 31 as the laminate 30 is shaped, and the cut end portion 50 a may not protrude from the warp yarns 34 on the warp layer 31 .
○ The fiber layers at both ends of the laminate 30 in the lamination direction Z may be the weft layers 32 .

○ The interlayer binding yarns 40 are the warp yarns 34 of the warp layer 31 located on the second surface 202, and one or more warp yarns 34 are skipped in the first arrangement direction X with respect to the warp yarns 34 located on the first surface 201. It may be hooked on the warp threads 34 .

(circle) the non-binding thread 50 may be arrange|positioned in the location which is not along the crease|fold N.
(circle) the fiber structure 20 may have only one flat part, and may have three or more. The fiber structure 20 may have two or more bends.

Ma... Matrix resin, N... Crease, X... First arrangement direction, Y... Second arrangement direction, Z... Lamination direction, 10... Fiber reinforced composite material, 20... Fiber structure, 21... First flat plate portion, 22... Bend portion 23 Second flat plate portion 30 Laminate 31 Warp layer as first fiber layer 32 Weft layer as second fiber layer 34 Warp as first fiber bundle 35 First 2 Weft yarns as fiber bundles, 40: interlaminar binding yarns, 50: non-bonding yarns, 50a: cut ends.

Claims (6)

A first fiber layer in which a plurality of first fiber bundles are arranged in a first arrangement direction and a second fiber layer in which a plurality of second fiber bundles are arranged in a second arrangement direction are laminated,
a laminate in which the first arrangement direction and the second arrangement direction are perpendicular to each other, and the fiber bundles of the fiber layers at both ends in the lamination direction are laminated in the same arrangement direction;
and an interlayer binding yarn that binds the laminate in the lamination direction,
A fiber structure having a flat portion where the first fiber bundle and the second fiber bundle extend linearly, and a bent portion where the fiber bundles in the same arrangement direction as the fiber layers positioned at both ends in the stacking direction are bent. There is
The first fiber bundle extends continuously between both ends of the fiber structure in the second arrangement direction, and the second fiber bundle extends continuously between both ends of the fiber structure in the first arrangement direction. and extends
Having a non-bonded yarn having a cut end formed by cutting the interlayer bonded yarn,
The flat plate portion has a portion bound in the lamination direction by the interlayer binding yarn,
The fiber structure, wherein the bent portion has a portion where the non-bonded yarn is arranged. 2. The fiber structure according to claim 1, wherein the bent portion has a projecting portion of the cut end on at least one of the fiber layers on both ends in the stacking direction. 3. The fiber structure according to claim 1, wherein the cut ends are located on the fiber layer positioned inside the bent portion among the fiber layers on both ends in the lamination direction. The fiber structure according to any one of claims 1 to 3, wherein the cut ends are arranged along the crease of the bent portion. The fiber structure according to any one of claims 1 to 4, wherein the non-bonded yarns are arranged over the entire area of the bent portion. A fiber-reinforced composite material made by impregnating a fiber structure with a matrix resin,
A fiber-reinforced composite material, wherein the fiber structure is the fiber structure according to any one of claims 1 to 5.

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