Locally-reinforced three-dimensional woven profile preform and preparation method thereof

Abstract

The invention provides a locally reinforced three-dimensional woven profile preform which is of an I-shaped structure and comprises a web, an upper flange and a lower flange, the length of the upper flange ranges from 35 mm to 45 mm, the length of the lower flange ranges from 35 mm to 45 mm, the width of the upper flange ranges from 110 mm to 130 mm, the width of the lower flange ranges from 110 mm to 130 mm, the thickness of the flanges ranges from 2.5 mm to 3.5 mm, the length of the web ranges from 95 mm to 105 mm, the width of the web ranges from 110 mm to 130 mm, and the thickness of the web ranges from 5 mm to 7 mm. On the basis of the special position and connection position structure of the profile component, weft yarn reinforcement and normal yarn and weft yarn composite reinforcement are carried out, and the problem that the component flange performance and the connection performance between the flange and the web are weak is solved in a local reinforcement mode.

Description

Technical Field

[0001] The invention relates to the technical field of textile methods, and in particular to a locally reinforced three-dimensional woven profile preform and a preparation method thereof. Background Art

[0002] The three-dimensional woven structure preform is usually composed of two systems of yarns, namely the binding warp yarn and the weft yarn. The binding warp yarn is along the forming direction of the preform, connecting the preform layers to each other, and the yarn is in a sinusoidal state inside the preform; when there is no load, the weft yarn is perpendicular to the forming direction of the preform and the yarn is in a straight line inside it. Its structure is highly designable and easy to prepare "T"-shaped, "I"-shaped, "X"-shaped and other profile components. At present, more weaving methods are to arrange the yarn cloth according to the shape of the profile, and the profile is directly formed after weaving. The biggest disadvantage of this method is that the profile size is easily limited by the number of heald frames and heald eyes, and it is impossible to continuously weave larger profile components.

[0003] To solve this problem, a flattening and restoring weaving method has emerged, which is to flatten the flange of the profile to form a regular shape with the web, and then unfold the flange to restore the profile shape after weaving according to the regular shape. This molding method solves the problem of limited profile size, but obvious grooves appear at the unfolding position of the web and flange, which becomes a local weak section of the preform and is prone to structural failure during service. Therefore, it is necessary to propose a preparation method that has a local reinforcement effect on the profile preform.

[0004] Patent CN 101775683 A discloses a normal-enhanced 2.5D fabric and a weaving method thereof, wherein the fabric comprises a warp yarn system and a weft yarn system, and the warp yarn system and the weft yarn system are interwoven into a layer-by-layer angle interlocking structure, and is characterized in that it also comprises a normal yarn system, which is perpendicular to the interwoven warp yarn system and weft yarn system, penetrates the thickness of the fabric, and is clamped by adjacent warp yarns and weft yarns to form the normal-enhanced 2.5D fabric. The fabric weaving method is based on the existing 2.5D fabric weaving method, and adds a normal yarn system, wherein the normal yarn is vertically introduced into the adjacent warp yarn columns one by one by a yarn introduction device along the weft yarn direction in a certain introduction mode, penetrates the thickness direction of the fabric, and is clamped by adjacent weft yarn columns to realize the weaving of the 2.5D fabric, and the specific process steps include initial yarn arrangement, opening movement, introduction of weft yarn, introduction of normal yarn, secondary opening movement, secondary introduction of weft yarn, and repeating the latter three steps to obtain the normal-enhanced 2.5D fabric. Among them, the patented technology adds a weft normal yarn system on the basis of layer-by-layer angle interlocking to form a normal reinforced 2.5D fabric. The normal yarn plays the role of binding the warp yarn in the thickness direction. Although the composite material made of the normal reinforced 2.5D fabric has a higher interlayer (normal) connection strength and improves the warp compressive performance, the degree of fiber buckling is a key factor affecting the compressive and bending properties. When the fabric is under load, the warp yarn buckles in a pattern of first decreasing and then increasing, while the sum of the warp and weft yarn buckling wave heights in the fabric is a constant. When the warp yarn buckles, the weft yarn buckles, and the straight weft yarn buckles at this time, and the strength contributed is greatly reduced. In addition, the weft density is usually less than the warp density, resulting in the weft compressive and bending properties of the 2.5D preform reinforced composite material being far inferior to the warp yarn, making the warp and weft compression strength and bending strength of the 2.5D preform reinforced composite material unbalanced. In the embodiment of this patent, a normal opening device is used to introduce weft normal yarns between warp yarn columns by winding or implanting. The opening device opens the warp yarns column by column and vertically introduces the normal yarns between adjacent warp yarns in turn. Since the warp density is usually large, this introduction method is inefficient and causes greater wear on the columnar fibers, which is not conducive to the consistent weaving of the preform.

[0005] "Design and Weaving of I-Shaped Three-Dimensional Woven Fabrics" (DOI: 10.19670 / j.cnki.dlgydxxb.2019.0311) designed and woven I-shaped three-dimensional woven fabrics using the flattening reduction method. The results show that the weaving method using flattening reduction is simple and effective, and to a certain extent solves the problem that the height of the web of ordinary I-shaped three-dimensional woven fabrics is limited by the number of heald frames during the weaving process. However, the upper and lower flanges and the web of the I-shaped fabric are designed with an angle interlocking structure. The disadvantages of this design are that the connection position between the upper and lower flanges and the web is uneven and there are obvious grooves, resulting in insufficient joint strength. In addition, in addition to having good compressive resistance during use, the upper and lower flanges of the profile will produce a large moment of inertia, and it is also required to be able to effectively resist the bending moment. If all parts use a shallow cross-bend structure, the upper and lower flanges will form local weak sections, and the mechanical enhancement effect of the key parts will not be achieved, which seriously affects the performance stability of the part during use.

[0006] Based on this, the present invention provides a method for preparing a locally reinforced three-dimensional woven profile preform. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is the flange weaving diagram, specifically a shallow cross-bend structure with weft reinforcement;

[0008] Figure 2 This is the weaving diagram of the connection between the flange and the web, which is a shallow cross-bend structure with weft reinforcement and normal composite reinforcement;

[0009] Figure 3 It is the weaving diagram of the web, specifically it is a shallow cross-bend structure;

[0010] Figure 4 It is a schematic diagram of an I-shaped component;

[0011] Figure 5 This is a weaving diagram using the flattened reduction method. Summary of the invention

[0012] The purpose of the present invention is to provide a locally reinforced three-dimensional woven profile preform and a preparation method thereof.

[0013] The present invention provides a method for preparing a locally reinforced three-dimensional woven profile preform, the steps comprising:

[0014] Furthermore, the three-dimensional woven profile preform is an I-shaped structure, including a web, an upper flange and a lower flange, the upper flange length is 35-45mm, the lower flange length is 35-45mm, the upper flange width is 110-130mm, the lower flange width is 110-130mm, the flange thickness is 2.5-3.5mm, the web length is 95-105mm, the web width is 110-130mm, and the web thickness is 5-7mm

[0015] Furthermore, the raw material of the preform is Zhongfu Shenying 3K carbon fiber, and the fiber volume fraction of the preform is 45%±5%.

[0016] Furthermore, the preform has a warp density of 8-10 strands / cm, a flange weft density of 6-8 strands / cm, a web weft density of 3-4 strands / cm, and the number of rows and columns is (10-14) rows × (88-130) columns.

[0017] Furthermore, the preform is woven with double warp yarns and single weft yarns, the web is a shallow cross bend structure, the flange is a shallow cross bend structure with weft reinforcement, and the connection between the flange and the web is a shallow cross bend structure with weft reinforcement and normal composite reinforcement.

[0018] Furthermore, the preform is woven by a flattening reduction method, that is, the I-shaped flange is flattened and woven together with the web as a flat plate; after weaving, the flange is unfolded to restore the I-shape; the flat plate is a flat plate formed by flattening the I-shaped preform, and the length of the flat plate is 170-190mm, the width is 110-130mm, and the thickness is 5-7mm.

[0019] Furthermore, the preform weaving step includes:

[0020] (1) Yarn threading: The normal reinforcing yarn is threaded at the local reinforcement position of the flange position and the connection. The warp yarn is fixed on the back beam. The normal reinforcing yarn in the first area is first inserted into the heald eyes of the third and fourth heald frames, and then passed through the reed and fixed to the breast beam; the normal reinforcing yarn is threaded in the two areas on both sides of the flange. The threading method of the second area is the same as that of the first area, and it is inserted into the heald eyes of the fifth and sixth heald frames;

[0021] (2) Two flange braiding:

[0022] (3) Using weft and normal composite reinforcement for local reinforcement weaving; the local reinforcement weaving includes reinforcement at the connection point and reinforcement after the connection point;

[0023] (4) Start weaving normally according to the structure of shallow cross bend until the web weaving is completed;

[0024] (5) Repeat the steps of reinforcing the connection point, reinforcing the connection point, and weaving the two flanges to the shape of the I-shaped preform after folding, and then restore the I-shaped shape after being removed from the machine to obtain a partially reinforced woven I-shaped preform.

[0025] Furthermore, before the threading of the reinforcing yarn, a normal threading is also included, and the normal threading step includes fixing the warp yarn on the rear beam of the loom equipment, threading it into the first and second heald frames in sequence according to the forward threading method, and then passing through the steel reed and fixing it on the breast beam. Each time the warp is threaded, after simultaneously threading into two adjacent layers of the same heald eye, the two warp yarns are then threaded into the same reed eye, and the threading is completed in sequence.

[0026] Further, the two flange braiding steps include:

[0027] When the weft is opened for the first time, an opening is formed on the first heald frame and on the second heald frame, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed.

[0028] When the weft is opened for the second time, the first and second heald frames do not move, so that the heald frames are in a horizontal position, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0029] When the third shedding occurs, the first heald frame is below and the second heald frame is above to form an opening, and weft yarns are introduced layer by layer except for the delamination, and the weft is beaten and formed;

[0030] When the weft is opened for the fourth time, the first and second heald frames do not move, so that the heald frames are in a horizontal position, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0031] The above is one cycle, and the process is repeated 14 times. After that, local reinforcement weaving begins.

[0032] Furthermore, the enhanced braiding step before the connection point includes:

[0033] When the weft is first shed, the weft yarns are introduced layer by layer except for the layered parts on the first, third and fifth heald frames and on the second, fourth and sixth heald frames for beating and shaping.

[0034] During the second shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, the third and fifth heald frames are below, and the fourth and sixth heald frames are above, forming an opening, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0035] The third shedding, the first, fourth, and sixth heald frames are under, and the second, third, and fifth heald frames are on, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0036] In the fourth shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, the third and fifth heald frames are below, and the fourth and sixth heald frames are above, forming an opening, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0037] The above is one cycle. After two cycles, the connection points will be enhanced.

[0038] Furthermore, the step of reinforcing the connection points comprises:

[0039] When the weft is opened for the first time, openings are formed on the first and third heald frames and on the second and fourth heald frames. At this time, weft yarns are introduced layer by layer for beating and forming.

[0040] In the second shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third heald frame below and the fourth heald frame above, forming an opening. At this time, weft yarns are introduced layer by layer for beating and shaping;

[0041] The third shedding, under the first and fourth heald frames, and above the second and third heald frames, is performed. At this time, weft yarns are introduced layer by layer, and the weft is beaten and formed.

[0042] In the fourth shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third heald frame below and the fourth heald frame above, forming an opening. At this time, weft yarns are introduced layer by layer for beating and shaping.

[0043] The above is one cycle, and the enhancement of the first local position is completed after two cycles.

[0044] The beneficial effects of the present invention are:

[0045] The object of the present invention is to provide a method for preparing a partially reinforced woven profile preform, wherein the three-dimensional woven structure includes an angle interlocking structure (also known as a 2.5D structure) and a three-dimensional orthogonal structure. A multi-heddle loom is used for weaving, and a weft-reinforced layer-by-layer angle interlocking structure ( Figure 1 ), the connection between the upper and lower flanges and the web adopts a layer-by-layer angle interlocking structure with warp normal yarn and weft yarn composite reinforcement ( Figure 2 ), the rest of the positions are woven as per the interlocking structure of the layers ( Figure 3 ).

[0046] On the one hand, the use of weft yarn reinforcement at the flange position is equivalent to increasing the weft density to more than twice the original value, narrowing the gap between warp and weft density, greatly improving the contribution of weft yarn to compressive and bending properties, and narrowing the difference in warp and weft performance, thereby increasing the stability of the warp and weft performance of the preform.

[0047] On the other hand, adding weft yarns and warp normal yarns at the connection position between the upper and lower flanges and the web can intuitively fill the connection position tightly. In addition, the weft reinforcing yarns cooperate with the warp normal yarns to bundle the weft yarns and weft reinforcing yarns in the warp direction respectively, without slipping due to the load at the connection position and without affecting the warp yarns. The structure of the connection position between the flange and the web is tight and flat, and the contribution of the warp and weft yarns to the local area is uniform and stable, thereby achieving the purpose of strengthening the local position of the profile component.

[0048] The present invention performs weft yarn reinforcement and normal yarn and weft yarn composite reinforcement on the basis of special positions and connection position structures of profile components, and solves the problems of weak component flange performance and weak connection performance between flange and web by local reinforcement.

[0049] The present invention adopts the principle of locally adding weft reinforcement yarn and normal reinforcement yarn, so that the flange and the connection position between the flange and the web are tighter and smoother, the connection force is stronger, and the risks brought by the weak load-bearing parts of the profile and the weak links of the connection positions of each part are greatly reduced. The weft reinforcement can greatly improve the contribution of the weft yarn at the flange position to the compressive performance and bending performance, and reduce the difference in warp and weft performance, and increase the warp and weft performance stability of the preform. The warp normal yarn can bundle the weft yarn and the weft reinforcement yarn in the warp direction respectively, and the fiber will not slip due to the load at the connection position, and will not affect the warp yarn, so that the structure of the connection position between the flange and the web is tight and smooth, and the contribution of the warp and weft yarns to the local area is uniform and stable.

[0050] The reinforcement of the normal yarn in the local reinforcement method of the present invention is to use the heald frame movement to drive the warp normal yarn movement, which is highly efficient and has less wear. The bundling action of each weft normal yarn is completed once, which is more efficient and reduces the wear on the fiber compared with the reinforcement of the weft normal yarn. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Example

[0053] In this embodiment, a piece of I-shaped preform is woven, such as Figure 4 As shown, the upper flange length is 40mm, the lower flange length is 40mm, the upper flange width is 120mm, the lower flange width is 120mm, the flange thickness is 3mm, the web length is 100mm, the web width is 120mm, and the web thickness is 6mm.

[0054] In a further embodiment, the upper flange length of the I-shaped three-dimensional woven profile preform can also be 35-45mm, the lower flange length can also be 35-45mm, the upper flange width can also be 110-130mm, the lower flange width can also be 110-130mm, the flange thickness can also be 2.5-3.5mm, the web length can also be 95-105mm, the web width can also be 110-130mm, and the web thickness can also be 5-7mm.

[0055] The fiber volume fraction of the preform is 45%, the warp density is 9 fibers / cm, the flange weft density is 7 fibers / cm, the web weft density is 3.5 fibers / cm, and the number of rows and columns is 12 rows×108 columns.

[0056] In a further embodiment, the warp density is 8-10 strands / cm, the flange weft density is 6-8 strands / cm, and the web weft density is 3-4 strands / cm.

[0057] Furthermore, the web weft density can be adjusted according to the actual load-bearing capacity.

[0058] The aforementioned specific weaving steps do not affect the unfolding of the shape.

[0059] The raw material is Zhongfu Shenying 3K carbon fiber, the warp yarn is double-stranded, the weft yarn is single-stranded, and the web is a shallow cross-bend structure, such as Figure 3 As shown;

[0060] The flange is a shallow cross-bend structure with weft reinforcement, such as Figure 1 As shown;

[0061] The connection between the flange and the web is a shallow cross-bend structure with composite reinforcement in the latitudinal direction and the normal direction. Figure 2 shown.

[0062] The flattening reduction method is used for weaving, that is, the I-shaped flange is flattened and integrated with the web as a flat plate. Figure 5 As shown;

[0063] After weaving is completed, the flange is unfolded to restore the shape. Figure 4 shown.

[0064] Implementation prerequisites:

[0065] Since the flattening reduction method is adopted for weaving, the flat plate (flattened into a flat plate shape) has a length of 180 mm, a width of 120 mm, and a thickness of 6 mm.

[0066] In a further embodiment, the plate may also be 170-190 mm in length, 110-130 mm in width, and 5-7 mm in thickness.

[0067] This embodiment adopts the warp weaving method. At this time, the warp yarns are distributed in the length direction, the flange and the web have more warp and weft interweaving points, and the connection force is strong.

[0068] (1) Flange reinforcement structure design: In order to ensure the compression and bending performance of the flange in actual working conditions, this part of the structure needs to be reinforced. The design structure is layer-by-layer corner interlocking plus weft reinforcement, such as Figure 1 .

[0069] (2) Strengthening structure design of the web-flange connection: The web-flange connection is a local weak node, and this part of the structure needs to be strengthened. The design structure is layer-by-layer corner interlocking plus weft reinforcement plus normal reinforcement, such as Figure 2 .

[0070] (3) Design of process parameters for local reinforcement positions: The local reinforcement positions of the I-shape are located at the flange and the connection between the web and the flange, a total of three locations.

[0071] Accordingly, the specific steps for preparing a partially reinforced three-dimensional woven profile preform in this embodiment are as follows:

[0072] (1) Yarn threading: The warp density at the flange position is designed to be 9 yarns / cm, and the weft density is 7 yarns / cm. The weaving is completed according to the length of the flange; the warp density at the connection position between the web and the flange is designed to be 18 yarns / cm, and the weft density is 7 yarns / cm. Four wefts are woven at the two connection positions, of which two wefts are distributed on the side of the connection position that is biased towards the web, and two wefts are distributed on the side of the connection position that is biased towards the flange; a total of 1,296 warp yarns are fixed on the rear beam of the loom equipment, and are sequentially threaded into the first and second heald frames according to the sequential threading method, and then passed through the steel reed and fixed on the breast beam. Each time the warp is threaded, after simultaneously threading into the two adjacent layers of the same heald eye, the two warp yarns are then threaded into the same reed eye, and threading is completed in sequence.

[0073] Among them, the loom equipment can be selected from 2.5D looms and flat looms, and the type of looms is not limited. Both can achieve the purpose of the present invention. In this embodiment, a 2.5D loom is used.

[0074] (2) Inserting normal reinforcing yarn: insert normal reinforcing yarn at the local reinforcement position (flange position and connection position), a total of 107 yarns, the warp yarn is fixed on the back beam, the normal reinforcing yarn in the first area is first inserted into the heald eyes of the third and fourth heald frames, and then passed through the reed and fixed to the breast beam.

[0075] Since there are two flanges at one connection position and each flange has reinforcing yarn, it is necessary to wear normal reinforcing yarn in two areas. The second area is worn in the same way as the first area and is worn into the heald eyes of the fifth and sixth heald frames.

[0076] (3) Two flange braiding:

[0077] When the weft is opened for the first time, an opening is formed on the first heald frame and on the second heald frame, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed.

[0078] When the weft is opened for the second time, the first and second heald frames do not move, so that the heald frames are in a horizontal position, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0079] When the third shedding occurs, the first heald frame is below and the second heald frame is above to form an opening, and weft yarns are introduced layer by layer except for the delamination, and the weft is beaten and formed;

[0080] When the weft is opened for the fourth time, the first and second heald frames do not move, so that the heald frames are in a horizontal position, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0081] The above is one cycle, and the process is repeated 14 times. After that, local reinforcement weaving begins.

[0082] Local reinforcement weaving includes reinforcement at the connection points and reinforcement behind the connection points, and performs weft-wise and normal-wise composite reinforcement. Its weaving pattern is different from normal weaving.

[0083] (7) Enhancement before the connection point:

[0084] When the weft is first shed, the weft yarns are introduced layer by layer except for the layered parts on the first, third and fifth heald frames and on the second, fourth and sixth heald frames for beating and shaping.

[0085] During the second shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, the third and fifth heald frames are below, and the fourth and sixth heald frames are above, forming an opening, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0086] The third shedding, the first, fourth, and sixth heald frames are under, and the second, third, and fifth heald frames are on, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed;

[0087] For the fourth opening, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third and fifth heald frames below and the fourth and sixth heald frames above, forming an opening, and weft yarns are introduced layer by layer except for the layered part, for beating and forming.

[0088] The above is one cycle. After two cycles, the connection points will be enhanced.

[0089] (8) Enhancement of connection points:

[0090] When the weft is opened for the first time, openings are formed on the first and third heald frames and on the second and fourth heald frames. At this time, weft yarns are introduced layer by layer for beating and forming.

[0091] In the second shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third heald frame below and the fourth heald frame above, forming an opening. At this time, weft yarns are introduced layer by layer for beating and shaping;

[0092] The third shedding, under the first and fourth heald frames, and above the second and third heald frames, is performed. At this time, weft yarns are introduced layer by layer, and the weft is beaten and formed.

[0093] In the fourth shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third heald frame below and the fourth heald frame above, forming an opening. At this time, weft yarns are introduced layer by layer for beating and shaping.

[0094] The above is one cycle, and the enhancement of the first local position is completed after two cycles.

[0095] (9) Start weaving normally according to the structure of shallow cross bend until the web weaving is completed.

[0096] (10) Repeat steps (8), (7), and (6) until the (shape of the I-shaped preform after folding) reaches the required length, and then restore the I-shaped shape after being removed from the machine to obtain a partially reinforced woven I-shaped preform.

[0097] By adding weft reinforcing yarns and normal reinforcing yarns at local positions of the profile, the connection and filling of the position are further strengthened, and the performance stability of the local position, the tightness and flatness of the connection point are structurally enhanced; by setting the appropriate density of weft reinforcing yarns and normal reinforcing yarns, the tightness and strength of the local position of the profile and the connection positions of each part can meet actual needs.

[0098] The present invention mainly realizes the reinforcement of yarn structure at the local position by adding weft reinforcement yarn at the local position of the profile and adding weft plus normal composite reinforcement yarn at the connection position, so that the flatness and tightness of the part are enhanced. In addition, the weft yarn and normal yarn are added to the local position of the preform in the present invention, and its operation method has complete regularity, no free play space, uniqueness, and greatly reduces the difficulty of operation. Profile components are widely used in various fields such as national defense science and technology, aerospace, transportation, biomedicine, sports equipment and chemical equipment. Among them, the "I"-shaped preform is in great demand for military and civilian dual-use satellite adapters, trusses and other connectors in the space field. "I"-shaped components and assembly components are widely used in the nebula star network.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A locally reinforced three-dimensional woven profile preform, characterized in that: The three-dimensional woven profile preform is an I-shaped structure, including a web, an upper flange and a lower flange, the upper flange is 35-45 mm long, the lower flange is 35-45 mm long, the upper flange is 110-130 mm wide, the lower flange is 110-130 mm wide, the flange thickness is 2.5-3.5 mm, the web length is 95-105 mm, the web width is 110-130 mm, and the web thickness is 5-7 mm.

2. A partially reinforced three-dimensional woven profile preform according to claim 1, characterized in that: The raw material of the preform is Zhongfu Shenying 3K carbon fiber, and the fiber volume fraction of the preform is 45%±5%.

3. The partially reinforced three-dimensional woven profile preform according to claim 1, characterized in that: The preform has a warp density of 8-10 strands / cm, a flange weft density of 6-8 strands / cm, a web weft density of 3-4 strands / cm, and the number of rows and columns is (10-14) rows×(88-130) columns.

4. The partially reinforced three-dimensional woven profile preform according to claim 1, characterized in that: The preform is woven with double warp yarns and single weft yarns, the web is a shallow cross bend structure, the flange is a shallow cross bend structure with weft reinforcement, and the connection between the flange and the web is a shallow cross bend structure with weft reinforcement and normal composite reinforcement.

5. A method for preparing a partially reinforced three-dimensional woven profile preform according to any one of claims 1 to 4, characterized in that: The preform is woven by a flattening reduction method, that is, the I-shaped flange is flattened and woven together with the web as a flat plate; after weaving, the flange is unfolded to restore the I-shape; the flat plate is a flat plate formed by flattening the I-shaped preform, and the length of the flat plate is 170-190mm, the width is 110-130mm, and the thickness is 5-7mm.

6. The method for preparing a partially reinforced three-dimensional woven profile preform according to claim 5, characterized in that: The preform weaving step comprises: (1) Yarn threading: The normal reinforcing yarn is threaded at the local reinforcement position of the flange position and the connection. The warp yarn is fixed on the back beam. The normal reinforcing yarn in the first area is first inserted into the heald eyes of the third and fourth heald frames, and then passed through the reed and fixed to the breast beam; the normal reinforcing yarn is threaded in the two areas on both sides of the flange. The threading method of the second area is the same as that of the first area, and it is inserted into the heald eyes of the fifth and sixth heald frames; (2) Two flange braids; (3) Using weft and normal composite reinforcement for local reinforcement weaving; the local reinforcement weaving includes reinforcement at the connection point and reinforcement after the connection point; (4) Start weaving normally according to the structure of shallow cross bend until the web weaving is completed; (5) Repeat the steps of reinforcing the connection point, reinforcing the connection point, and weaving the two flanges to the shape of the I-shaped preform after folding, and then restore the I-shaped shape after being removed from the machine to obtain a partially reinforced woven I-shaped preform.

7. The method for preparing a partially reinforced three-dimensional woven profile preform according to claim 6, characterized in that: Before the threading of the reinforcing yarn, a normal threading is also included. The normal threading step includes fixing the warp yarn on the rear beam of the loom equipment, threading it into the first and second heald frames in sequence according to the forward threading method, and then passing it through the reed and fixing it on the breast beam; each time the warp is threaded, after simultaneously passing it into two adjacent layers of heald eyes of the same heald, the two warp yarns are then threaded into the same reed eye, and the threading is completed in sequence.

8. The method for preparing a partially reinforced three-dimensional woven profile preform according to claim 6, characterized in that: The two flange braiding steps include: When the weft is opened for the first time, an opening is formed on the first heald frame and on the second heald frame, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed. When the weft is opened for the second time, the first and second heald frames do not move, so that the heald frames are in a horizontal position, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed; When the third shedding occurs, the first heald frame is below and the second heald frame is above to form an opening, and weft yarns are introduced layer by layer except for the delamination, and the weft is beaten and formed; When the weft is opened for the fourth time, the first and second heald frames do not move, so that the heald frames are in a horizontal position, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed; The above is one cycle, and the process is repeated 14 times. After that, local reinforcement weaving begins.

9. The method for preparing a partially reinforced three-dimensional woven profile preform according to claim 6, characterized in that: The enhanced braiding step before the connection point includes: When the weft is first shed, the weft yarns are introduced layer by layer except for the layered parts on the first, third and fifth heald frames and on the second, fourth and sixth heald frames for beating and shaping. During the second shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, the third and fifth heald frames are below, and the fourth and sixth heald frames are above, forming an opening, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed; The third shedding, the first, fourth, and sixth heald frames are under, and the second, third, and fifth heald frames are on, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed; In the fourth shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, the third and fifth heald frames are below, and the fourth and sixth heald frames are above, forming an opening, and weft yarns are introduced layer by layer except for the layered part, and the weft is beaten and formed; The above is one cycle. After two cycles, the connection points will be enhanced.

10. The method for preparing a partially reinforced three-dimensional woven profile preform according to claim 6, characterized in that: The step of reinforcing the connection points comprises: When the weft is opened for the first time, openings are formed on the first and third heald frames and on the second and fourth heald frames. At this time, weft yarns are introduced layer by layer for beating and forming. In the second shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third heald frame below and the fourth heald frame above, forming an opening. At this time, weft yarns are introduced layer by layer for beating and shaping; The third shedding, under the first and fourth heald frames, and above the second and third heald frames, is performed. At this time, weft yarns are introduced layer by layer, and the weft is beaten and formed. In the fourth shedding, the first and second heald frames do not move, so that the heald frames are in a horizontal position, with the third heald frame below and the fourth heald frame above, forming an opening. At this time, weft yarns are introduced layer by layer for beating and shaping. The above is one cycle, and the enhancement of the first local position is completed after two cycles.

Images