CN112538680B - Hollow box-shaped fiber reinforcement, preparation method thereof and preparation method of hollow box - Google Patents

Abstract

The invention discloses a hollow box-shaped fiber reinforcement, a preparation method thereof and a preparation method of a hollow box, wherein the box bottom, the box body and the cushion layer of the hollow box-shaped fiber reinforcement are integrally woven, and the side wall of the box is not scattered; a first surface connection is formed between the connecting part at the bottom of the box body and the box bottom; the bottom arm of the cushion layer is in surface butt joint with the box bottom, the reinforcing arm is in surface butt joint with the side wall of the box, the box bottom is connected with the box body through a second surface, and after matrix materials are injected into the prefabricated part and cured, the strength of the side wall of the box is improved; the two surfaces are connected, so that the box bottom and the box body are firmly connected, the rigidity of the whole hollow box is improved, and the mechanical property of the hollow box is improved; in the preparation method, the box body prefabricated part and the cushion layer prefabricated part are bent by being attached to the wall of the middle mold or the top mold to form the hollow channel, and only the flat-plate-shaped prefabricated part is woven in the weaving process without weaving the hollow channel, so that the preparation difficulty of the hollow box is reduced and the preparation precision of the hollow box is improved.

Description

Hollow box-shaped fiber reinforcement, preparation method thereof and preparation method of hollow box

Technical Field

The invention belongs to the general technical field of three-dimensional weaving and manufacturing of fiber reinforced structures, and particularly relates to a hollow box-shaped fiber reinforcement body, a preparation method thereof and a preparation method of a hollow box.

Background

At present, most of high-strength and high-modulus structural members are prepared from composite materials, and generally, a fiber preform prepared by a weaving method is adopted, and then an injection molding matrix is adopted to densify the fiber preform so as to obtain the structural member of the composite materials. For example, the fibers may be exfoliated fibers, carbon fibers, or ceramic fibers, and the matrix may be a resin or carbon.

For example, chinese patent document CN104395515B discloses a method for manufacturing a hollow box-shaped structural member, wherein the cross section of the hollow box-shaped structural member is an inverted pi shape, the tops of two side walls of the inverted pi shape are connected to form a closed opening, the tail of the hollow box-shaped structural member is a closed end, the head of the hollow box-shaped structural member is an open opening, and the box body has a required radian from the tail to the head.

The preparation method of the hollow box-shaped structural member comprises the following steps: weaving the first portion, the second portion and the third portion; the first part, the second part and the third part are distributed from top to bottom in sequence, parameters of weaving middle yarns and weft yarns are preset in advance according to the radian required by the side wall of the preset box body, so that the warp yarns and the weft yarns in the middle of the third part and the middle of the second part are interwoven into a whole, and the two ends of the third part and the second part are layered; the middle of the first part and the second part is separated, and the warp yarns and the weft yarns at the two ends are mutually interwoven and connected together to form a connecting area; then, the first part is pulled upwards, so that a hollow cavity is formed between the first part and the second part, and a braided prefabricated body is formed; the connecting area of the first part and the second part is horizontally convex outwards, so that the side wall of the hollow box-shaped structure is in a required radian, the hollow box-shaped structure is convenient to install in a space consistent with the radian of the box body of the hollow box-shaped structure, and the convex parts of the two connecting areas of the first part and the second part need to be cut off; and then, placing the woven prefabricated part on a mold in a mold cavity for positioning, and pouring a matrix material into the mold cavity for curing and molding.

In addition to the above-mentioned hollow box body having an inverted pi-shaped cross section, most of the existing other hollow box-shaped structural members having opposite shapes, such as a hollow box body having a cross section in the shape of a hill, are manufactured by the above-mentioned manufacturing method.

However, in the above-mentioned preparation method, since the protruding portion of the connection region between the first portion and the second portion needs to be cut off before the woven preform is placed in the mold cavity, since the sidewall of the box body needs to form a certain curvature, the thickness of the sidewall is relatively thin, the box top where the first portion is located and the box body where the second portion is located are prone to scattering, even if the subsequent matrix material is cured and molded, the box top and the box body are connected insecurely, which finally affects the low rigidity and poor mechanical properties of the hollow box-shaped structural member.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is that the box top and the box body of the existing hollow box-shaped fiber reinforcement are easy to scatter, even if the subsequent matrix material is cured and formed, the box top and the box body are not firmly connected, and finally the low rigidity and the poor mechanical property of the hollow box-shaped structural member are influenced.

Therefore, the invention provides a hollow box-shaped fiber reinforcement, which comprises an integrally woven box bottom, an integrally woven box body and a woven cushion layer; the box body comprises a box top, two side walls which are bent and extend downwards from two sides of the box top, and a connecting part of which one side wall is bent outwards and is close to one side of the box bottom, the connecting part is laminated and attached to the box bottom, and a hollow channel is defined between the box body and the box bottom; at least one opening end is formed between the head part of the box body and the head part of the box bottom along the length direction of the box body;

the cushion layer is attached to the inner wall of the hollow channel and at least comprises a bottom arm attached to the box bottom and a reinforcing arm attached to the side wall.

Optionally, in the hollow box-shaped fiber reinforcement, there are two reinforcing arms, and the two reinforcing arms are respectively attached to the inner surfaces of the side walls on both sides in an abutting manner.

Optionally, in the hollow box-shaped fiber reinforcement, an upward protruding step is woven in the middle of the upper surface of the box bottom;

the bottom arm of the cushion abuts against the landing, and the inner surface of the bottom of any one of the side walls abuts against the outer side wall surface of the landing adjacent thereto.

Optionally, in the hollow box-shaped fiber reinforcement, the tail part of the box top abuts against the tail part of the box bottom to form a closed end.

The invention provides a preparation method of the hollow box-shaped fiber reinforcement, which comprises the following steps:

opening the mold: preparing a top die consistent with the shape of the box body and a bottom die consistent with the shape of the bottom of the box according to the shape of a preset hollow box; the middle mold is consistent with the shape of the hollow channel of the preset hollow box;

weaving: weaving a flat-plate-shaped box bottom prefabricated body, a box body prefabricated body and a cushion layer prefabricated body respectively;

stacking: stacking the bottom die, the box bottom prefabricated body, the cushion layer prefabricated body, the box body prefabricated body and the top die in sequence, wherein the box bottom prefabricated body is used as a box bottom;

bending:

bending the box body prefabricated body along the joint and the inner wall surface of the top die to form a box top, a side wall of a box and a connecting part, wherein the connecting part is laminated and jointed on the edge of the box bottom prefabricated body; attaching the head part of the box top to the head part of the top die, forming an opening end between the head part of the box top and the head part of the box bottom, and clamping the edges of the connecting part and the box bottom on the edges of the top die and the bottom die;

bending at least one end of the cushion layer prefabricated body in the width direction of the top die upwards along the inner wall surface of the adjacent box side wall to form a reinforcing arm attached to the inner wall surface of the side wall of the box and a bottom wall abutted to the bottom of the box, and enclosing a required hollow channel between the bent cushion layer prefabricated body and the box body prefabricated body;

shaping, namely inserting the middle mold into the hollow channel, so that the top of the box is clamped by the top mold and the middle mold, the side wall of the box and the reinforcing arm are clamped by the side wall of the top mold and the side wall of the middle mold, and the bottom of the box and the bottom wall of the cushion layer are clamped by the bottom of the middle mold and the bottom mold;

or

Stacking: sequentially stacking a bottom die, a box bottom prefabricated body, a cushion layer prefabricated body, a middle die and a box body prefabricated body in a stacking mode, wherein the box bottom prefabricated body serves as a box bottom;

bending:

bending at least one end of the cushion layer prefabricated body in the width direction of the middle mold upwards along the outer wall surface of the middle mold adjacent to the middle mold to form a reinforcing arm attached to the outer wall surface of the middle mold and a bottom wall abutted against the box bottom;

bending the box body prefabricated body along the outer wall surface of the middle die or the reinforcing arm which is attached to the box body prefabricated body and adjacent to the box body prefabricated body to form a box top, a side wall and a connecting part of the box, laminating the connecting part on the edge of the box bottom, attaching the head of the box top to the head of the middle die, and forming an opening end between the head of the box top and the head of the box bottom;

shaping: and pressing the top die on the top surface of the box body, so that the box top is clamped between the outer wall surface of the middle die and the inner wall surface of the top die, the side wall and the reinforcing arm of the box are clamped between the outer wall surface of the middle die and the inner wall surface of the top die, and the box bottom and the bottom wall are clamped between the bottom of the middle die and the bottom die to form a required hollow channel.

Optionally, in the bending step, two ends of the cushion layer preform in the width direction of the top mold or the middle mold are respectively bent upwards along the inner wall surface attached to the top mold or the outer wall surface attached to the middle mold to form a reinforcing arm.

Alternatively, in the above method for producing a hollow box-shaped fiber reinforcement, in the knitting step, a step of knitting an upwardly projecting step is knitted at the middle portion of the upper surface of the box bottom preform;

in the stacking step, the cushion layer prefabricated body is stacked on the step;

in the bending step, the box body preform is bent outward along the edge of the bottom of the step to form the connection portion.

Optionally, the above method for preparing a hollow box-shaped fiber reinforcement further comprises, before the weaving step, the steps of:

when the preset hollow box is spread, the boundary line of the peripheral edge of the terrace is used as a weaving boundary line; the interior of the weaving boundary line is used as an interconnected weaving area, and the exterior of the weaving boundary line is used as a non-interconnected weaving area;

in the weaving process, the warp yarns and the weft yarns in the interconnected weaving area are interwoven and two adjacent layers are interwoven and connected to form an interconnected weaving area;

within the non-interlinked knitted zones, knitting in layers to form separate upper and lower knitted zones, bounded by knitting boundaries;

and after the interconnected weaving area and the non-interconnected weaving area are woven, cutting off the upper-layer weaving area in the non-interconnected weaving area to form the box bottom prefabricated body with the step.

Optionally, in the above method for preparing a hollow box-shaped fiber reinforcement, in the step of weaving the cushion layer preform, a single layer of cloth is woven by interweaving single layers of weft yarns and warp yarns.

Alternatively, in the above method for producing a hollow box-shaped fiber reinforcement, the tail portion of the box top is abutted against the tail portion of the box bottom in the bending step to form the closed end.

The invention also provides a preparation method of the hollow box, which comprises the following steps:

preparing a hollow box-shaped fiber reinforcement by using the method for preparing the hollow box-shaped fiber reinforcement;

and injecting a matrix material into the hollow box-shaped fiber reinforcement body, and curing the matrix material to form a hollow box.

The technical scheme of the invention has the following advantages:

1. the invention provides a hollow box-shaped fiber reinforcement, which comprises an integrally woven box bottom, an integrally woven box body and a woven cushion layer; the box body comprises a box top, two side walls which are bent and extend downwards from two sides of the box top, and a connecting part of which one side wall is bent outwards and is close to one side of the box bottom, the connecting part is laminated and attached to the box bottom, and a hollow channel is defined between the box body and the box bottom; at least one opening end is formed between the head part of the box body and the head part of the box bottom along the length direction of the box body; the cushion layer is attached to the inner wall of the hollow channel and at least comprises a bottom wall attached to the box bottom and a reinforcing arm attached to the side wall.

In the hollow box-shaped fiber reinforcement body with the structure, the box bottom, the box body and the cushion layer are integrally woven, so that the side wall of the box can not scatter; the connecting part at the bottom of the box body is laminated on the box bottom, so that a first surface is formed between the connecting part and the box bottom; the bottom arm of bed course forms the face butt with the top surface at the bottom of the box between, strengthens and forms the face butt between the internal face of the lateral wall of arm and box, makes and forms the second road surface butt between the bottom of the box and the box body. When the matrix material is injected into the hollow box-shaped fiber reinforcement body and cured, the side wall of the box can not scatter, and the strength of the side wall of the box can be improved; the first road surface butt joint and the second road surface butt joint are in surface connection, so that the connection between the box bottom and the box body is firm, the rigidity of the whole hollow box is improved, and the mechanical property of the hollow box is improved.

2. The invention provides a preparation method of a hollow box-shaped fiber reinforcement, which comprises the following steps: the method comprises the following steps of die opening, weaving, stacking, bending and shaping, wherein in the die opening step, a top die consistent with the shape of a box body and a bottom die consistent with the shape of the bottom of a box bottom are prepared according to the shape of a preset hollow box; the middle mold is consistent with the shape of the hollow channel of the preset hollow box; in the weaving step, a flat-plate-shaped box bottom prefabricated body, a box body prefabricated body and a cushion layer prefabricated body are respectively woven; in the step of stacking, stacking a bottom die, a box bottom prefabricated body, a cushion layer prefabricated body, a middle die, a box body prefabricated body and a top die in a stacking manner, and in the step of bending, bending the box body prefabricated body and the cushion layer prefabricated body along the outer wall surface of the middle die or the inner wall surface of the top die to form a box top, the side wall and the connecting part of the box, the bottom wall and the reinforcing arm of the cushion layer; the top die and the bottom die clamp the edges of the connecting part and the box bottom, and the bent box body prefabricated body, the box bottom prefabricated body and the cushion layer prefabricated body are shaped under the matching of the middle die, the top die and the bottom die so as to form the hollow box-shaped fiber reinforcement body of the hollow channel taking the middle die as the appearance.

In the preparation method of the hollow box-shaped fiber reinforcement, a box bottom prefabricated body, a cushion layer prefabricated body and a box body prefabricated body are respectively integrally woven into a flat plate shape; then the flat plate-shaped prefabricated body is arranged in a stacking mode with a bottom die, a middle die or a top die, the cushion layer prefabricated body and the box body prefabricated body are bent by the inner wall surface of the top die or the outer wall surface of the middle die, and finally the box body prefabricated body, the box bottom prefabricated body and the cushion layer prefabricated body are limited and shaped by the top die, the top die and the middle die to form a hollow box-shaped fiber reinforcement body of a required hollow channel, so that only the flat plate-shaped prefabricated body is woven in the weaving process without weaving the hollow channel, and the preparation difficulty of the hollow box is reduced and the preparation precision of the hollow box is improved; meanwhile, according to the shapes of the top die, the top die and the middle die, a hollow channel with any shape trend can be formed.

3. The invention also provides a preparation method of the hollow box, which comprises the preparation method of the hollow box-shaped fiber reinforcement body; and injecting a matrix material into the hollow box-shaped fiber reinforcement body, and curing the matrix material to form a hollow box.

The preparation method of the hollow box simplifies the preparation method of the hollow box and can prepare the hollow box with any shape due to the adoption of the preparation method of the hollow box-shaped fiber reinforcement.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural view of a hollow box provided in embodiment 1 of the present invention;

FIG. 2 is a schematic structural view of a body preform of the hollow box of FIG. 1;

FIG. 3a is a schematic diagram of the structure of a bottom preform of the hollow box of FIG. 1;

FIG. 3b is a schematic cross-sectional view of the bottom preform of FIG. 3a taken along line V1-V1;

FIG. 4 is a schematic view of the construction of a mat preform of the hollow box of FIG. 1;

FIG. 5 is a schematic cross-sectional view of the preform body taken along line V-V of FIG. 2;

FIG. 6 is a schematic cross-sectional view of the bottom preform of FIG. 3a taken along line V1-V1 when the upper knit region within the non-interlinked knit regions is not subtracted;

FIG. 7 is a schematic cross-sectional view VII-VII of the blanket preform of FIG. 4;

description of reference numerals:

10-hollow box;

20-box body prefabricated body; 21-a connecting part; 22-a side wall; 23-box top; 20 a-a second bend line; 20 b-a third bend line;

30-a box bottom preform; 31-lower layer weaving area; 32-upper layer weaving area; 33-a landing; 30 a-knit demarcation line;

40-a cushion layer preform; 41-a reinforcing arm; 42-bottom arm; 40 a-first bend line.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Example 1

This example provides a hollow box-like fiber reinforcement, as shown in fig. 1, a first embodiment of the hollow box-like fiber reinforcement comprising an integrally woven box bottom, an integrally woven box body, and a woven cushion layer; the box body comprises a box top 23, two side walls 22 which are bent and extend downwards from two sides of the box top 23, and a connecting part 21 which is bent outwards from one side of any side wall 22 close to the box bottom.

The middle part of the upper surface of the box bottom is woven with an upward convex step 33, the connecting part 21 is laminated on the box bottom and positioned outside the side wall 22 of the step 33 adjacent to the connecting part, and a hollow channel is formed by the box body and the box bottom; an opening end is formed between the head part of the box body and the head part of the box bottom along the length direction of the box body; the cushion layer is attached to the inner wall of the hollow channel and comprises a bottom arm 42 attached to the top of the step 33 and reinforcing arms 41 attached to the inner wall surfaces of the side walls 22 on the two sides, so that the cushion layer is distributed in a U shape with an upward opening; the inner surface of the bottom of any one of the side walls 22 abuts against the outer side wall surface of the landing 33 adjacent thereto.

In the hollow box-shaped fiber reinforcement of the embodiment, the box bottom is integrally woven, the box body is integrally woven, and the box body comprises the box top 23, the two side walls 22 of the box and the connecting part 21, so that the side walls 22 of the box are not scattered; because the connecting part 21 at the bottom of the box body is laminated on the box bottom, the connecting part 21 and the box bottom form surface butt to be used as a first connection; the inner wall surface of the bottom of the side wall 22 of the box body and the outer wall surface of the step 33 form surface contact to form a second connection; the bottom arm of the cushion layer is in surface contact with the top surface of the step 33, and the two reinforcing arms 41 are in surface contact with the inner wall surfaces of the two side walls 22 of the box body as a third connection.

After the matrix material is injected into the hollow box-shaped fiber reinforcement body and cured, the side wall 22 of the box can not scatter, so that the strength of the side wall 22 of the box can be improved; the first connection, the second connection and the third connection are all in surface connection, so that the connection between the box bottom and the box body is firm, the rigidity of the whole hollow box 10 is improved, and the mechanical property of the hollow box is improved.

Correspondingly, the present embodiment also provides a method for preparing the hollow box-shaped fiber reinforcement of the first embodiment, which includes the following steps:

s0 (mold opening step): preparing a top die consistent with the shape of the box body and a bottom die consistent with the shape of the bottom of the box according to the shape of a preset hollow box; and the middle die is consistent with the shape of the hollow channel of the preset hollow box.

The bottom mold, the middle mold and the top mold are used for assisting the box body preform 20, the box bottom preform 30 and the cushion layer preform 40 to form the hollow channel, so that the top mold, the middle mold and the bottom mold are customized in advance according to the shape and the hollow channel of the prefabricated hollow box 10.

For example, before knitting, parameters of the prefabricated hollow box 10 are determined according to the requirement of the hollow box 10, then the existing CAD three-dimensional modeling is adopted to model the structure of the prefabricated hollow box 10 and further open the mold, so as to form a top mold, a bottom mold and a middle mold with required shapes, and correspondingly, the radian and the shape of the bottom surface of the middle mold and the top surface of the step 33 are kept consistent.

S10 (knitting step): the box bottom preform 30, the box body preform 20 and the cushion preform 40 are respectively woven into a flat plate shape.

Specifically, the step of knitting the box body preform 20: a plurality of layers of weft yarns and warp yarns are interwoven to form a flat-plate-shaped box body preform 20, as shown in fig. 2.

For example, the weft yarns and the warp yarns are made of fiber materials, and the fiber materials are preferably carbon fibers, glass fibers, ceramic fibers and the like; and interweaving a plurality of layers of weft yarns and a plurality of layers of warp yarns by using a 2.5D fiber machine to weave two adjacent layers of the flat-plate-shaped box body prefabricated body 20 which are connected in an interweaving way.

As shown in fig. 5, the warp yarns of the box body preform 20 are seven layers, the weft yarns are multiple layers, and the number of the warp yarns may also be other layers, such as two layers, three layers, four layers, five layers, six layers, eight layers, and the like, and the specific number of the layers is set according to actual requirements.

Knitting the box bottom prefabricated body 30:

before the knitting step, when the box 10 is spread according to the preset hollow space, the boundary line of the peripheral edge of the landing 33 is used as a knitting boundary line 30a, as shown in fig. 3, the inner part of the knitting boundary line 30a is used as an interconnected knitting area 302, and the outer part of the knitting boundary line 30a is used as a non-interconnected knitting area 301; in fig. 3, the step 33 extends from the tail portion to the head portion of the box bottom preform 30, and two knitting boundary lines 30a of the step 33 are provided, respectively on the left and right sides of the step 33.

In the weaving process, the warp yarns and the weft yarns in the interconnected weaving area 302 are interwoven and two adjacent layers are interwoven and connected to form an interconnected weaving area 302; in the non-interlinked weaving zone 301, with the weaving boundary line 30a as a boundary, the weaving is performed in layers to form an upper weaving zone 32 and a lower weaving zone 31, the warp yarns and the weft yarns of the upper weaving zone 32 are interwoven with each other and the two adjacent layers are interwoven and connected; the warp yarns and the weft yarns in the lower layer weaving area 31 are mutually interwoven and are connected with two adjacent layers in an interweaving way; the warp yarns of the upper woven extent 32 are separated from the weft yarns of the lower woven extent 31, and adjacent fibre layers are separated.

Finally, the upper woven extent 32 within the non-interlinked woven extent 301 is cut away to form the box bottom preform 30 with the landing 33.

The knitting of the box bottom preform 30 will be described by taking as an example the schematic diagram of the knitting of the box bottom preform 30 shown in fig. 6, and in the knitting process, the knitting can be performed sequentially from the tail portion toward the head portion of the box bottom in the longitudinal direction of the box bottom, and when knitting is performed to the knitting boundary line 30a, the warp yarns and the weft yarns in the fiber layers c1 to c10 in the interlining knitting area 302 are interwoven and the two adjacent layers are interwoven and connected to each other to form the interlining knitting area 302; in the non-interlinked weaving zone 301, weaving is carried out in layers to form an upper weaving zone 32 and a lower weaving zone 31, the warp yarns and the weft yarns of the c 1-c 3 fiber layers of the upper weaving zone 32 are interwoven and connected with each other in two adjacent layers; the warp yarns of the c 4-c 10 fiber layers in the lower weaving zone 31 are interwoven with the weft yarns and the adjacent two layers are interwoven, but the weft yarns and warp yarns in the c4 fiber layer are separated from the weft box warp yarns of the c3 fiber layer to be woven in layers to form the non-interlinked weaving zone 301. If from the total width of the fiber layers, adjacent two layers of the c 1-c 3 fiber layers are interwoven and connected to form a first integral structure, and adjacent two layers of the c 4-c 10 fiber layers are interwoven and connected to form another second integral structure.

Considering that the upper knitting region 32 and the lower knitting region 31 in the non-interlinked knitting region 301 are separately and independently knitted, knitting may be performed simultaneously using a three-dimensional knitting machine during the knitting process; after knitting, the fiber layers c 4-c 10 of the non-interlinked knitted region 301 are cut off, and the box bottom preform 30 with the upward protruding step 33 on the upper surface is formed.

In the box bottom weaving process, warp yarns penetrate from the tail part of the box bottom to the head part of the box bottom, weft yarns and warp yarns are made of fiber materials, and the fiber materials are preferably carbon fibers, glass fibers, ceramic fibers and the like; the number of layers of the yarn layers in the interconnected weaving area 302 and the non-interconnected weaving area 301 can be increased or decreased according to actual needs, the specific number of layers is not limited, and only the number of layers of the yarn layers in the interconnected weaving area 302 is equal to the number of layers of the yarn layers in the non-interconnected weaving area 301. For example, the number of yarn layers in the interconnected knitting area 302 is eight, the number of yarn layers in the upper knitting area 32 in the non-interconnected knitting area 301 is two, and the number of yarn layers in the lower knitting area 31 is six; alternatively, the yarn layer of the upper woven zone 32 is four layers and the yarn layer of the lower woven zone 31 is four layers in the non-interlinked woven zone 301.

Alternatively, in the step of knitting the box bottom preform, knitting may be performed from the head portion of the box bottom toward the tail portion of the box bottom, and the specific knitting method is the same as that described above and is not described herein again.

Weaving of the cushion layer preform 40: a single layer of flat single layer cloth is woven by interweaving single layer warp yarns and weft yarns, as shown in figure 7. Of course, the cushion layer preform 40 may be a single layer of cloth, and may also be similar to the above-mentioned box body preform 20, and a flat-plate-shaped cushion layer preform 40 formed by interweaving a plurality of layers of weft yarns and a plurality of layers of warp yarns and connecting two adjacent layers of warp yarns is adopted, and the specific number of weaving layers is not limited and is determined according to the requirement. Since the cushion layer preform 40 mainly serves to further strengthen the firmness of the connection between the side wall 22 of the box body and the box bottom, it is preferable that the yarn layer of the cushion layer preform 40 is less than that of the box body preform 20.

S20 (stacking): and stacking the bottom die, the box bottom prefabricated body 30, the cushion layer prefabricated body 40, the middle die and the box body prefabricated body 20 in sequence.

In the stacking step: the box bottom prefabricated body is placed on the bottom die, and the cushion layer prefabricated body 40 is stacked on the top surface of the step 33 of the box bottom prefabricated body 30; the middle mold is placed on the upper surface of the cushion layer preform 40, and the bottom surface of the middle mold is aligned with the top of the landing 33; the body preform 20 is stacked on the top surface of the middle mold.

S30 (bending) comprises the following steps:

s301: bending two ends of the cushion layer prefabricated body 40 in the width direction of the middle mold upwards along the outer wall surfaces attached to the two side walls of the middle mold, and folding a first bending line 40a, wherein as shown in fig. 4, the bent two ends are respectively attached to the outer wall surfaces of the side walls of the two sides of the middle mold, and the cushion layer prefabricated body 40 forms a bottom arm 42 abutted to the step 33 and two reinforcing arms 41 attached to the outer wall surfaces of the side walls of the two sides of the middle mold by taking the first bending line 40a as a boundary;

s302, step: the box body preform 20 is bent along the outer wall surfaces of the middle mold and the reinforcing arms attached adjacent thereto to form the box top 23, the box side walls 22, and the connecting portions 21:

specifically, the method comprises the following steps: the top of the box body preform 20 is attached to the top surface of the middle mold, and is bent downward along the top edge of the side wall of the middle mold to form a second bending line 20a, as shown in fig. 2, and a box top 23 is formed between the two second bending lines; then, the downward bending part of the box body preform 20 is attached to the outer wall surface of the adjacent reinforcing arm 41 and the outer wall surface of the side wall 22 of the step 33 and extends downward until the bottom edge of the step 33, and then is bent outward along the edge of the bottom of the step 33 to form a third bending line 20b, and the part between the second bending line 20a and the third bending line 20b on the same side of the box body preform 20 forms the side wall 22 on one side of the box; forming a connecting part 21 on the box body prefabricated body 20 except the third bending line 20b by taking the third bending line 20b as a boundary, wherein the connecting part 21 is laminated and attached on the edge of the box bottom;

attaching the head part of the box top 23 to the head part of the middle mold, and forming an opening end between the head part of the box top and the head part of the box bottom to form a hollow channel taking the middle mold as the appearance;

shaping: the top die is pressed on the outer wall surface of the bent box body, so that the box top is clamped between the top of the middle die and the top of the top die, the side wall and the reinforcing arm of the box are clamped between the side wall of the middle die and the side wall of the top die, the edge of the connecting part and the edge of the box bottom are clamped between the edges of the top die and the bottom die, and the bottom arm and the box bottom are clamped between the middle die and the bottom die, so that the hollow box-shaped fiber reinforcement body can be formed.

In the preparation method of the hollow box-shaped fiber reinforcement, a box body prefabricated body 20, a box bottom prefabricated body 30 and a cushion layer prefabricated body 40 are respectively integrally woven, the box body prefabricated body 20, the box bottom prefabricated body 30 and the cushion layer prefabricated body 40 are in a flat plate shape in the weaving process, the box bottom prefabricated body 30 is arranged on the woven flat plate shape, and an upper weaving area 32 in a non-interconnected weaving area 301 is cut off to form a step table 33; then, the box bottom prefabricated body, the cushion layer prefabricated body and the box body prefabricated body are distributed on the bottom die and the middle die in a stacking mode, the box body prefabricated body 20 and the cushion layer prefabricated body 40 are bent according to the shape of the middle die to form a box top 23, two side walls 22 of the box, bottom arms of the cushion layer and two reinforcing arms 41, and the bent box body prefabricated body, box bottom prefabricated body and cushion layer prefabricated body are shaped under the matching of the top die, the bottom die and the middle die to finally form a hollow box-shaped fiber reinforcing body with a required hollow channel, so that only the flat-plate-shaped prefabricated body is woven in the weaving process without weaving the hollow channel, and the preparation difficulty of the hollow box is reduced and the preparation precision of the hollow box is improved; meanwhile, a bottom die, a middle die and a top die with different shapes and radian trends can be designed according to needs to form hollow channels with different radian trends, so that various hollow box-shaped fiber reinforcements with different properties can be prepared, and meanwhile, the preparation precision of the hollow channels is high.

In addition, the thicknesses of the body preform 20, the bottom preform 30 and the cushion preform 40 can be adjusted on-line by increasing or decreasing yarn layers in the knitting process according to the needs.

Correspondingly, the present embodiment further provides a method for preparing the hollow box 10, including the following steps:

a method for preparing the hollow box-shaped fiber reinforcement;

the hollow box-like fiber reinforcement is impregnated with a matrix material, the matrix material is deposited in the pores of the fiber material, and after the matrix material is cured, the box body is joined together with the box bottom and the cushion layer to form the hollow box 10. For the matrix material, a resin material is general, and for example, the matrix material is an epoxy resin, a polyimide resin, or the like.

In the method for manufacturing the hollow box 10 according to this embodiment, by using the method for manufacturing the preform of the hollow box 10, and curing the matrix material, the first surface connection is formed between the connecting portion 21 at the bottom of the box body and the box bottom, and the second surface connection is formed between the inner wall surface at the bottom of the box body and the outer wall surface of the adjacent step 33; the bottom arm of the cushion layer is in surface connection with the step 33, and the two reinforcing arms 41 of the cushion layer are in surface connection with the inner wall surfaces of the side walls 22 on the two sides of the box body respectively, so that the box bottom and the box body form a third surface connection, the connection firmness of the box body and the box bottom is further enhanced, the strength of the hollow box 10 is improved, and the mechanical property of the hollow box 10 is improved.

As an alternative embodiment, after the hollow box 10 is molded, the hollow box 10 may be machined to a desired size by machining, depending on the desired size of the hollow box 10; or further processing the hollow box 10 for molding.

Example 2

This example provides a hollow box-like fiber reinforcement that differs from the hollow box-like fiber reinforcement provided in example 1 in that:

the step 33 at the bottom of the hollow box-shaped fiber reinforcement is replaced by a groove (not shown in the figure) which is concave downwards, the bottom arm 42 of the cushion layer is laminated and attached on the bottom of the groove, and the reinforcing arm is abutted on the groove wall of the groove and the inner wall surface of the side wall of the box. Therefore, the thickness of the box bottom is changed through the arrangement of the grooves or the terraces, and the thickness of the box bottom can be changed according to requirements.

Accordingly, in the method of manufacturing the hollow box-shaped fiber reinforcement according to this embodiment, the grooves are woven in the same manner as the steps, and the boundary line between the peripheral edges of the grooves is used as a weaving boundary line, except that: the inner part of the weaving boundary line is used as a non-interconnected weaving area, and the outer part of the weaving boundary line is used as an interconnected weaving area;

in the weaving process, warp yarns and weft yarns in the interconnected weaving area are interwoven and two adjacent layers are interwoven and connected to form an interconnected weaving area; in the non-interconnected weaving area, the weaving boundary is used as a boundary, layered weaving is carried out to form an upper layer weaving area and a lower layer weaving area, the warp yarns and the weft yarns in the upper layer weaving area are interwoven, and two adjacent layers are interwoven and connected; the warp yarns and the weft yarns in the lower layer weaving area are mutually interwoven and are connected with two adjacent layers in an interweaving way; the warp yarns and the weft yarns of the upper weaving area and the lower weaving area are separated, and the adjacent fiber layers are separated; and finally, cutting off the upper-layer woven area in the non-interconnection area to form a groove.

In the stacking step, the cushion layer prefabricated body is stacked in the groove, two ends of the cushion layer prefabricated body in the width direction of the middle mold or the top mold are positioned outside the groove, and the bottom of the middle mold is embedded in the groove so as to be stacked on the cushion layer prefabricated body;

in the bending step, the cushion layer prefabricated body is bent upwards along the outer side wall of the attached middle die to form a reinforcing arm; the bottom of the side walls of the box body preform are bent outwards along the edge of the reinforcing arm or middle die at the notch of the groove to form the connection.

Example 3

This example provides a hollow box-like fiber reinforcement which differs from the hollow box-like fiber reinforcement provided in example 1 in that:

the hollow box-shaped fiber reinforcement has a box bottom without the step 33, and the box bottom is flat, and the bottom arms 42 of the cushion layer are laminated on the box bottom.

In the hollow box-shaped fiber reinforcement body with the structure, the box bottom is a flat plate block, and the connecting part 21 at the bottom of the box body is still in first surface butt joint with the box bottom; the reinforcing arm 41 of the cushion layer is in face abutting connection with one side wall 22 of the box, the bottom arm of the cushion layer is in face abutting connection with the box bottom, a second road surface abutting connection is formed between the side wall 22 of the box and the box bottom through the cushion layer, and after the matrix material is cured in the hollow box-shaped fiber reinforced body, the rigidity and the mechanical property of the hollow box 10 can be improved.

Accordingly, the method for producing a hollow box-shaped fiber reinforcement of this embodiment is different from the method for producing a hollow box-shaped fiber reinforcement of example 1 in that:

in the step of knitting the box bottom preform 30, it is not necessary to knit the interconnected knitting area 302 and the non-interconnected knitting area 301, the knitting method is the same as the knitting method of the box body preform 20 in embodiment 1, and any two adjacent layers of flat-plate-shaped preforms which are interlaced and connected are directly knitted, which is not described herein again;

in the step of S20 (stacking), the bottom die, the box bottom prefabricated body 30, the cushion layer prefabricated body 40, the middle die and the box body prefabricated body 20 are sequentially stacked and stacked; the mat layer preform 40 is directly stacked on the upper surface of the case bottom.

S302, step: the box body preform 20 is bent along the outer wall surface of the attached middle mold to form the box top 23, the box side wall 22, and the connecting portion 21:

the top of the box body preform 20 is attached to the top surface of the middle mold, and is bent downwards along the top edges of the side walls 22 at two sides of the middle mold to form second bending lines 20a, and a box top 23 is formed between the two second bending lines; then, the downward bending part of the box body preform 20 is attached to the outer wall surface of the adjacent reinforcing arm 41 or the outer wall surface of the side wall 22 of the middle die and extends downward until the bottom edge of the middle die, and then the downward bending part is bent outward along the bottom edge of the middle die to form a third bending line 20b, and the part, located between the second bending line and the third bending line 20b on the same side, of the box body preform 20 forms a side wall 22 of the box; the box body preform 20 is formed with a connection portion 21 at a portion other than the third bending line 20b, with the third bending line 20b being defined, and the connection portion 21 is laminated on the edge of the box bottom.

Except for the above steps, other steps are the same as those in embodiment 1, and are not repeated herein, please refer to the description of embodiment 1.

Example 4

This example provides a hollow box-like fiber reinforcement which differs from the hollow box-like fiber reinforcement provided in example 1 in that:

the spacer includes the aforementioned bottom arm 42 and one reinforcing arm 41, and the reinforcing arm 41 is disposed in abutment with the inner wall surface of the one side wall 22 of the case, correspondingly.

In the hollow box-shaped fiber reinforcement of this embodiment, since the box is integrally woven, even if the cushion layer is provided with one reinforcing arm 41, since the bottom arm 42 surface of the cushion layer abuts on the step 33 of the box bottom and the reinforcing arm 41 surface abuts on the inner surface of the one side wall 22 of the box body, the cushion layer can further strengthen the connection of the box body and the box bottom together after the matrix material is injected into the hollow box-shaped fiber reinforcement and cured.

Accordingly, in the method for producing a hollow box-shaped fiber reinforcement, the difference is only that:

s20 (stacking): stacking the bottom die, the box bottom prefabricated body 30, the cushion layer prefabricated body 40, the middle die and the box body prefabricated body 20 in sequence; aligning one end side wall of the cushion layer preform 40 with one end side wall of the step 33, and if there is an excess portion, cutting off the excess portion;

s301: bending the other end of the cushion layer prefabricated body 40 in the width direction of the middle die upwards along the outer wall surface of the side wall attached to the middle die to form a first bending line 40a, wherein the bent end is attached to the outer wall surface of the side wall 22 of the middle die, and the cushion layer prefabricated body 40 forms a bottom arm 42 abutted against the step 33 and a reinforcing arm 41 attached to the outer wall surface of the side wall attached to the middle die by taking the first bending line 40a as a boundary;

s302, a step: the side wall 22 of the case body is attached to the outer wall surface of the side wall of the intermediate mold, and the other side wall is attached to the outer wall surface of the reinforcing arm 41.

As a modified embodiment of the hollow box-shaped fiber reinforcement provided in the above-described examples 1, 2, 3 and 4:

the tail of the box top 23 of the hollow box-shaped fiber reinforcement is connected in abutment with the tail of the box bottom to form a closed end. So that the tail part of the hollow box-shaped fiber reinforcement body is a closed end, and the head part of the hollow box-shaped fiber reinforcement body is an open end; correspondingly, in the bending step, the tail of the cassette top 23 is abutted against the tail of the cassette bottom to form a closed end.

Or, two open ends are formed between the tail part of the box top 23 and the tail part of the box bottom of the hollow box-shaped fiber reinforcement, correspondingly, in the bending step, the tail part of the box top 23 is abutted against the tail part of the middle mold, and then the other open end is formed between the tail part of the box top 23 and the tail part of the box bottom.

In a word, in the preparation method of the hollow box-shaped fiber reinforcement, the box bottom prefabricated body, the cushion layer prefabricated body and the box body prefabricated body are respectively integrally woven into a flat plate shape; then the fiber reinforcement is overlapped with a bottom die, a middle die or a top die, and the box body preform and the cushion layer preform are bent according to the shape of the middle die or the top die, so that a hollow box-shaped fiber reinforcement with the shape of the middle die as a hollow channel can be formed, and the weaving method of the preform and the method for forming the hollow channel are simplified; meanwhile, hollow channels with any shape trend can be formed according to the shapes of the bottom die, the top die and the middle die.

As a modification of the above examples 1, 2, 3, 4 and any one of the alternative embodiments, in the method for producing a hollow box-shaped fiber reinforcement according to the modification, the stacking step, the bending step, and the setting step are different from those described above, and specifically:

in the stacking step, the bottom die, the box bottom prefabricated body, the cushion layer prefabricated body, the box body prefabricated body and the top die are sequentially stacked;

in the bending step: bending the box body prefabricated body along the inner wall surface of the joint and top die to form a box top, a side wall of the box and a connecting part, wherein the connecting part is laminated and jointed on the edge of the box bottom prefabricated body; attaching the head part of the box top to the head part of the top die, forming an opening end between the head part of the box top and the head part of the box bottom, and clamping the edges of the connecting part and the box bottom on the edges of the top die and the bottom die;

bending at least one end of the cushion layer prefabricated body in the width direction of the top die upwards along the inner wall surface of the adjacent box side wall to form a reinforcing arm attached to the inner wall surface of the side wall of the box and a bottom wall abutted to the bottom of the box, and enclosing a required hollow channel between the bent cushion layer prefabricated body and the box body prefabricated body;

and (3) shaping, namely inserting the middle mold into the hollow channel, so that the top of the box is clamped by the top mold and the middle mold, the side wall and the reinforcing arm of the box are clamped by the side wall of the top mold and the side wall of the middle mold, and the bottom of the box and the bottom wall of the cushion layer are clamped by the bottom of the middle mold and the bottom mold.

In this embodiment, the box body preform and the cushion layer preform are first bent along the inner wall surface of the top mold to form a hollow channel, and finally the middle mold is inserted into the hollow channel, and the bent box body preform, box bottom preform and cushion layer preform are positioned under the cooperation of the middle mold, the bottom mold and the top mold to form a hollow box-shaped fiber reinforcement body of the desired hollow channel.

The above examples 2 and 3 and the modification also include a method for manufacturing the hollow case 10, which is the same as that in example 1 and is not described again.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (11)

1. A method for preparing a hollow box-shaped fiber reinforcement is characterized by comprising the following steps:

opening the mold: preparing a top die consistent with the shape of the box body and a bottom die consistent with the shape of the bottom of the box body according to the shape of a preset hollow box; the middle mold is consistent with the shape of the hollow channel of the preset hollow box;

weaving: weaving a flat-plate-shaped box bottom prefabricated body (30), a box body prefabricated body (20) and a cushion layer prefabricated body (40) respectively;

stacking: stacking the bottom die, the box bottom prefabricated body (30), the cushion layer prefabricated body (40), the box body prefabricated body (20) and the top die in sequence, wherein the box bottom prefabricated body is used as a box bottom;

bending:

bending the box body prefabricated body (20) along the inner wall surface of the attaching and top die to form a box top (23), a side wall of the box and a connecting part (21), wherein the connecting part (21) is laminated and attached to the edge of the box bottom prefabricated body (30); attaching the head part of the box top (23) to the head part of the top die, forming an opening end between the head part of the box top and the head part of the box bottom, and clamping the edges of the connecting part and the box bottom on the edges of the top die and the bottom die;

bending at least one end of the cushion layer prefabricated body (40) in the width direction of the top die upwards along the inner wall surface of the adjacent box side wall to form a reinforcing arm (41) attached to the inner wall surface of the side wall of the box and a bottom wall (42) abutted to the bottom of the box, and enclosing a required hollow channel between the bent cushion layer prefabricated body and the box body prefabricated body;

shaping, namely inserting the middle mold into the hollow channel, so that the top of the box is clamped by the top mold and the middle mold, the side wall of the box and the reinforcing arm are clamped by the side wall of the top mold and the side wall of the middle mold, and the bottom of the box and the bottom wall of the cushion layer are clamped by the bottom of the middle mold and the bottom mold;

or

Stacking: sequentially stacking the bottom die, the box bottom prefabricated body (30), the cushion layer prefabricated body (40), the middle die and the box body prefabricated body (20) in a stacking mode, wherein the box bottom prefabricated body serves as a box bottom;

bending:

bending at least one end of the cushion layer prefabricated body (40) in the width direction of the middle mold upwards along the outer wall surface of the middle mold adjacent to the middle mold to form a reinforcing arm (41) attached to the outer wall surface of the middle mold and a bottom wall (42) abutted to the box bottom;

bending the box body prefabricated part (20) along the outer wall surface of the middle die or the reinforcing arm adjacent to the box body prefabricated part in a fitting mode to form a box top (23), the side wall of the box and a connecting part (21), wherein the connecting part (21) is laminated and attached to the edge of the box bottom, the head part of the box top (23) is attached to the head part of the middle die, and an opening end is formed between the head part of the box bottom and the head part of the middle die;

shaping: the top die is pressed on the top surface of the box body, so that the box top is clamped between the outer wall surface of the middle die and the inner wall surface of the top die, the side wall and the reinforcing arm of the box are clamped between the outer wall surface of the middle die and the inner wall surface of the top die, and the box bottom and the bottom wall are clamped between the bottom of the middle die and the bottom die to form a required hollow channel.

2. The method for producing a hollow box-like fiber reinforcement according to claim 1,

in the bending step, two ends of the cushion layer prefabricated body (40) in the width direction of the top die or the middle die are respectively bent upwards along the inner wall surface attached to the top die or the outer wall surface attached to the middle die to respectively form a reinforcing arm (41).

3. The method for producing a hollow box-like fiber reinforcement according to claim 1,

in the knitting step, knitting a terrace (33) protruding upward at the middle of the upper surface of the box bottom preform (30);

in the stacking step, a cushion layer prefabricated body (40) is stacked on the step (33);

in the bending step, the box body preform (20) is bent outward along the edge of the bottom of the step (33) to form the connection portion (21).

4. The method of producing a hollow box-like fiber reinforcement according to claim 3,

before the weaving step, the method also comprises the following steps:

when the preset hollow box (10) is spread, the boundary line where the peripheral edge of the terrace (33) is located is used as a weaving boundary line; the inner part of the knitted dividing line (30a) is used as an interconnected knitted region (302), and the outer part of the knitted dividing line (30a) is used as a non-interconnected knitted region (301);

in the weaving process, the warp yarns and the weft yarns in the interconnected weaving area (302) are mutually interwoven and two adjacent layers are interwoven and connected to form the interconnected weaving area (302);

within the non-interlinked knitted zone (301), bounded by a knitting boundary line (30a), knitted in layers to form a separate upper knitted zone (32) and lower knitted zone (31);

after the interconnected woven region and the non-interconnected woven region are woven, cutting off an upper woven region (32) in the non-interconnected woven region (301) to form a box bottom preform (30) with a step (33).

5. Method for the production of a hollow box-like fiber reinforcement according to any one of claims 1-4, characterized in that in the step of weaving a cushion layer preform, a single layer of cloth is woven by interlacing a single layer of weft yarns with warp yarns.

6. Method for producing a hollow box-like fiber reinforcement according to any one of claims 1-4, characterized in that in the bending step, the tail of the box top (23) is brought into abutment against the tail of the box bottom to form a closed end.

7. A hollow box-shaped fiber reinforcement produced by the method for producing a hollow box-shaped fiber reinforcement according to any one of claims 1 to 6;

the hollow box-shaped fiber reinforcement comprises an integrally woven box bottom, an integrally woven box body and a woven cushion layer; the box body comprises a box top (23), two side walls (22) which are bent and extend downwards from two sides of the box top (23), and a connecting part (21) which is bent outwards and is arranged at one side of any side wall (22) close to the box bottom, the connecting part (21) is laminated and attached to the box bottom, and a hollow channel is defined between the box body and the box bottom; at least one opening end is formed between the head part of the box body and the head part of the box bottom along the length direction of the box body;

the cushion layer is attached to the inner wall of the hollow channel and at least comprises a bottom arm (42) attached to the box bottom and a reinforcing arm (41) attached to the side wall (22).

8. The hollow box-like fiber reinforcement according to claim 7, wherein the number of the reinforcing arms (41) is two, and the two reinforcing arms (41) are respectively attached to the inner surfaces of the side walls (22) on both sides in an abutting manner.

9. The hollow box-like fiber reinforcement according to claim 7 or 8, wherein an upwardly protruding step (33) is woven at the middle of the upper surface of the box bottom;

the bottom arm (42) of the cushion abuts against the landing (33), and the inner surface of the bottom of any one of the side walls (22) abuts against the outer side wall surface of the landing (33) adjacent thereto.

10. Hollow box-shaped fiber reinforcement according to claim 7 or 8, characterized in that the tail of the box top (23) abuts the tail of the box bottom forming a closed end.

11. The preparation method of the hollow box is characterized by comprising the following steps:

production of a hollow box-like fiber reinforcement by the method for producing a hollow box-like fiber reinforcement according to any one of claims 1 to 6;

and injecting a matrix material into the hollow box-shaped fiber reinforcement body, and curing the matrix material to form a hollow box.

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