Preparation method of special-shaped three-dimensional fabric

Abstract

The invention relates to the technical field of three-dimensional fabric forming, in particular to a preparation method of a special-shaped three-dimensional fabric, which comprises the following steps: drawing a U-shaped cross-sectional view, and defining a coating area A between a first area parting line and the outer edge of the U-shaped cross-sectional view; the two second area dividing lines, the first area dividing line and the bottom edge of the straight-edge groove define a center splicing area C, and the second area dividing lines, the first area dividing line and the side edge of the straight-edge groove define a side splicing area B; cutting and flattening the U-shaped sectional view along the two second region segmentation lines to obtain a flattened sectional view; designing the number, the density and the fineness of warp yarns in a central splicing area C, a side splicing area B and a covering area A in the flattened sectional view; designing the number of strands of weft yarns and weft insertion structures in a central splicing area C and a side splicing area B in the flattened cross-sectional view; the weft yarns are subjected to traction and tightening finishing, so that the unfolded fabric is bent and deformed, and the special-shaped three-dimensional fabric is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of three-dimensional fabric forming, and in particular to a method for preparing special-shaped three-dimensional fabric. Background Art

[0002] High-performance composite materials prepared with three-dimensional fabrics as reinforcement structures have good integrity, strong designability, good weight reduction effect, excellent mechanical properties, and functional characteristics such as wave transmission, wave absorption, high temperature resistance, and ablation resistance. They have been used in many fields such as industrial products, aviation and aerospace; three-dimensional fabrics are continuous fiber bundles that are orderly intertwined in space to form an integral structure. Their organizational structures include: 2.5D, 2.5D weft lining, three-way orthogonal, three-dimensional weaving, needle punching and stitching structures; three-dimensional fabrics are usually designed with fiber distribution according to the cross-section of the product profile, including regular profiles (such as rectangles, trapezoids or circles) and special-shaped profiles. By regularly designing the fiber distribution in space, three-dimensional fabrics with different special structures are prepared.

[0003] In the prior art, most three-dimensional fabrics are prepared and molded once to form composite materials. For example, Chinese patent CN103031651B and Chinese patent CN110258003B describe the preparation of a rotary shell product with a 2.5D structure; Chinese patent CN101899739B describes the preparation of a 2.5D curved plate-mounted fabric; Chinese patent CN109914031B describes the preparation of a three-dimensional woven structure hourglass-shaped fabric; the above patents mostly use a one-time molding method to prepare three-dimensional fabrics, which is difficult to mold.

[0004] Therefore, in view of the above problems, the present invention urgently needs to provide a method for preparing a special-shaped three-dimensional fabric. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing a special-shaped three-dimensional fabric, divide and unfold the special-shaped three-dimensional fabric according to the cross-sectional shape, design the distribution of warp yarns and weft yarns, prepare the unfolded fabric based on the design parameters, and then perform bending and deformation finishing based on the unfolded fabric, finally realizing the overall preparation of the special-shaped three-dimensional fabric with a U-shaped portion.

[0006] The present invention provides a method for preparing a special-shaped three-dimensional fabric, wherein the special-shaped three-dimensional fabric has a U-shaped portion with a U-shaped cross section, and a straight-edge groove is provided on the top of the U-shaped portion. The preparation method comprises the following steps:

[0007] S1, draw a U-shaped cross-sectional view according to the U-shaped cross-sectional shape of the U-shaped portion, offset a certain distance inward along the outer edge of the U-shaped cross-sectional view to obtain a first area dividing line, and a covering area A is formed between the first area dividing line and the outer edge of the U-shaped cross-sectional view; connect the turning points on both sides of the first area dividing line with the corresponding end points of the bottom edge of the straight-edge groove on the adjacent side to obtain a second area dividing line, and the two second area dividing lines, the first area dividing line and the bottom edge of the straight-edge groove are formed to form a central splicing area C, and each second area dividing line, the first area dividing line and the side edge of the adjacent straight-edge groove are formed to form a side splicing area B; cut the U-shaped cross-sectional view along the two second area dividing lines, flatten the covering area A and the side splicing area B, and obtain a flattened cross-sectional view;

[0008] S2, according to the area change rate of the central splicing area C, the side splicing area B and the covering area A in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the preset parameters of the special-shaped three-dimensional fabric, the number of warp yarns, the density of warp yarns and the fineness of warp yarns in the central splicing area C, the side splicing area B and the covering area A in the flattened cross-sectional view are designed;

[0009] S3, according to the height ratio of the side of the central stitching area C and the side stitching area B in the flattened cross-sectional view, determine the ratio of the number of weft yarn layers in the central stitching area C and the side stitching area B; based on the preset parameters of the special-shaped three-dimensional fabric and the ratio of the number of weft yarn layers in the central stitching area C and the side stitching area B, design the number of weft yarns and the weft insertion structure in the central stitching area C and the side stitching area B in the flattened cross-sectional view, wherein a single weft yarn horizontally passes through the one side stitching area B, the central stitching area C and the other side stitching area B in sequence;

[0010] S4, based on the parameters obtained in S2 and S3, an unfolded fabric is prepared, and each weft yarn is pulled and tightened to make the unfolded fabric bend and deform until the two side edges of the central splicing area C are completely fitted with one side of the corresponding side splicing area B, thereby obtaining a special-shaped three-dimensional fabric.

[0011] Preferably, the preset parameters include the total warp yarn density, the total number of warp yarn layers, the total weft yarn density and the total number of weft yarn layers of the special-shaped three-dimensional fabric.

[0012] Preferably, S21, according to the areas and area change rates of the central stitching area C, the side stitching area B and the covering area A in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the total warp yarn density of the special-shaped three-dimensional fabric, the number of warp yarns, the warp yarn density and the warp yarn fineness in the central stitching area C, the side stitching area B and the covering area A in the unfolded fabric are calculated, and yarn addition processing is performed on the local area with a large area change rate;

[0013] S22, based on the total number of warp yarn layers of the special-shaped three-dimensional fabric, the number of warp yarn layers is designed according to the height correspondence between the central splicing area C and the side splicing area B in the U-shaped cross-sectional view and the flattened cross-sectional view; a stepped splicing area is designed on both side edges of the central splicing area C and the inner side edges of the side splicing area B in the flattened cross-sectional view, and the number of warp yarn columns is designed according to the number of warp yarn layers and the angle of the splicing area of ​​the central splicing area C and the side splicing area B in the unfolded fabric, so as to obtain the warp yarn arrangement of the central splicing area C and the side splicing area B in the flattened cross-sectional view.

[0014] Preferably, S31, according to the height ratio of the side edge of the central splicing area C to the side edge of the adjacent side splicing area B in the flattened cross-sectional view, based on the total number of weft yarn layers of the special-shaped three-dimensional fabric, determining the number of weft yarn layers in the central splicing area C and the side splicing area B;

[0015] S32, determining the weft yarn fineness and weft insertion structure in the central splicing area C and the side splicing area B according to the number of weft yarn layers in the central splicing area C and the side splicing area B and the thickness of the special-shaped three-dimensional fabric.

[0016] Preferably, S41, based on the design parameters obtained in S2 and S3 and the size of the flattened cross-sectional view, the unfolded fabric is prepared, and the three-dimensional fabric is bent and deformed with the axis of symmetry of the central splicing area C as a reference;

[0017] S42, during the bending deformation process, the weft yarns described in S3 are pulled, tightened and arranged so that each weft yarn is straightly distributed in the central splicing area C and the side splicing area B, until the two side edges of the central splicing area C are completely fitted with one side of the corresponding side splicing area B, and the excess weft yarns are removed to complete the forming of the special-shaped three-dimensional fabric.

[0018] Preferably, the special-shaped three-dimensional fabric is one of a 2.5D structure, a 2.5D weft-inserted structure, and other variable-structure 2.5D structures.

[0019] Preferably, the symmetry plane of the central splicing area C coincides with the symmetry plane of the U-shaped portion of the special-shaped three-dimensional fabric.

[0020] Preferably, before S4, a pressing plate having a length greater than that of the shaped three-dimensional fabric is prepared, and the unfolded fabric is fixed to the upper surface of the pressing plate along the symmetry plane of the central splicing area C and the thickness direction of the shaped three-dimensional fabric using multiple single-row needles, and multiple bending deformations are performed with the pressing plate as a fixed reference.

[0021] Preferably, the distance between each single row of needles is 20-40 mm.

[0022] Preferably, in S2, yarn adding treatment is performed on the bottom of the central splicing area C and the arc portion of the covering area A with a large area change rate in the U-shaped cross-sectional view and the flattened cross-sectional view, so that the warp yarn density is increased within 20% and the warp yarn fineness is increased to twice.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] According to the cross-sectional shape of the special-shaped three-dimensional fabric, the distribution of the warp and weft yarns is designed after the fabric is divided and unfolded. The unfolded fabric is prepared based on the design parameters, and then the bending deformation is performed based on the unfolded fabric. Finally, the overall preparation of the special-shaped three-dimensional fabric with a U-shaped part is realized.

[0025] The present invention provides a method for preparing a special-shaped three-dimensional fabric, which is divided and unfolded according to the cross-sectional shape of the special-shaped three-dimensional fabric, and the number, density and fineness of the warp yarns and the weft yarns are designed based on the area changes of each part of the flattened cross-sectional view and the U-shaped cross-sectional view. The unfolded fabric is prepared based on the designed fabric parameters, and then each weft yarn is pulled and tightened, so as to bend and deform the unfolded fabric, and finally the overall preparation of the special-shaped three-dimensional fabric is achieved; at the same time, the present invention also performs a step-by-step design on the splicing area, so that during the deformation process, the warp yarns and weft yarns in the splicing area are connected to form an integral structure, the splicing gaps generated during the bending deformation process are eliminated, and the integrity of the product is improved; compared with the one-time close-size weaving forming, the preparation method of the special-shaped three-dimensional fabric of the present invention reduces the difficulty of process operation through two-time forming of weaving and deformation; in addition, the secondary deformation forming can reduce the dependence of the fabric on special weaving equipment, and the production of complex surface products can be completed under conventional equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 1 is a structural schematic diagram (cross-sectional view) of a U-shaped portion of a special-shaped three-dimensional fabric according to an embodiment of the present invention;

[0027] Figure 2 is a structural schematic diagram (cross-sectional view) of the unfolded fabric according to an embodiment of the present invention;

[0028] Figure 3 is an operation schematic diagram of step S4 in the method for preparing a special-shaped three-dimensional fabric according to an embodiment of the present invention;

[0029] Figure 4 The shaped three-dimensional fabric is obtained in step S4 of the method for preparing the shaped three-dimensional fabric according to the embodiment of the present invention;

[0030] Figure 5 is a production flow chart of a method for preparing a special-shaped three-dimensional fabric according to an embodiment of the present invention;

[0031] Figure 6 is a schematic structural diagram of a special-shaped three-dimensional fabric according to another embodiment of the present invention;

[0032] Figure 7 It is a schematic structural diagram of a special-shaped three-dimensional fabric according to another embodiment of the present invention.

[0033] Among them: 1. Covering area A; 2. Side splicing area B; 3. Center splicing area C; 4. First area dividing line; 5. Second area dividing line. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. 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.

[0035] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, a method for preparing a special-shaped three-dimensional fabric, the special-shaped three-dimensional fabric has a U-shaped portion with a U-shaped cross section, a straight-edge groove is provided on the top of the U-shaped portion, wherein the symmetry axis of the straight-edge groove coincides with the symmetry axis of the U-shaped portion, and the method for preparing the U-shaped portion comprises the following steps:

[0036] S1, a U-shaped cross-sectional view is drawn according to the U-shaped cross-sectional shape of the U-shaped portion, and the U-shaped outer edge of the U-shaped cross-sectional view is offset inward by a certain distance to obtain a first area dividing line 4, and a covering area A1 is formed between the first area dividing line 4, the outer edge of the U-shaped cross-sectional view and the upper edge of the U-shaped cross-sectional view; the first area dividing line 4 obtained by the offset of the U-shaped outer edge includes a straight line segment, an arc segment and a straight line segment connected in sequence, and the turning points on both sides of the first area dividing line 4, i.e., the intersection points of each straight line segment and the arc segment, are respectively connected to the end point of the bottom edge of the straight-edge groove on the adjacent side. Line, obtain two second area dividing lines 5, the two second area dividing lines 5, the arc segment of the first area dividing line 4 and the bottom edge of the straight-edge groove are surrounded to form a central joint area C3, and each second area dividing line 5, the straight segment of the first area dividing line 4, the side of the adjacent straight-edge groove and the upper edge of the U-shaped cross-section are surrounded to form a side joint area B2; cut the U-shaped cross-section along the two second area dividing lines 5, separate the central joint area C3 from the two side joint areas B2, flatten the covering area A1 and the side joint area B2, and obtain a flattened cross-section;

[0037] S2, according to the area change rate of the central splicing area C3, the side splicing area B2 and the covering area A1 in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the preset parameters of the special-shaped three-dimensional fabric, the number of warp yarns, the density of warp yarns and the fineness of warp yarns in the central splicing area C3, the side splicing area B2 and the covering area A1 in the flattened cross-sectional view are designed;

[0038] Among them, firstly, with respect to the U-shaped cross-sectional view, the area proportions of the central stitching area C3, the side stitching area B2 and the covering area A1 are calculated respectively, and based on the total warp yarn density of the special-shaped three-dimensional fabric, the number of warp yarns in the central stitching area C3, the side stitching area B2 and the covering area A1 in the flattened cross-sectional view is calculated; at the same time, when the number of warp yarns remains unchanged, during the flattening process, the change rate of the warp yarn density in the same area is inversely proportional to the area change rate, thereby calculating the warp yarn density of the central stitching area C3, the side stitching area B2 and the covering area A1 in the flattened cross-sectional view, and combining the type of three-dimensional fabric, the warp yarn fineness of the central stitching area C3, the side stitching area B2 and the covering area A1 in the flattened cross-sectional view is calculated;

[0039] S3, calculating the height ratio of the side of the central stitching area C3 in the flattened cross-sectional view to the side of the adjacent side stitching area B2, and obtaining the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2; based on the preset parameters of the special-shaped three-dimensional fabric and the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2, obtaining the number of weft yarn layers in the central stitching area C3 and the side stitching area B2 in the flattened cross-sectional view, and designing the number of weft yarns and the weft insertion structure in the central stitching area C3 and the side stitching area B2 in the flattened cross-sectional view, wherein a single weft yarn horizontally passes through the stitching area B2 on one side, the central stitching area C3 and the stitching area B2 on the other side in sequence;

[0040] S4, based on the parameters obtained in S2 and S3, an unfolded fabric is prepared, and each weft yarn is pulled, tightened and arranged to make the unfolded fabric bend and deform until the two side edges of the central splicing area C3 are completely fitted with one side of the corresponding side splicing area B2, thereby obtaining a special-shaped three-dimensional fabric.

[0041] The present invention provides a method for preparing a special-shaped three-dimensional fabric, which is divided and unfolded according to the cross-sectional shape of the special-shaped three-dimensional fabric, and the number, density and fineness of the warp yarns and the weft yarns are designed based on the area changes of each part of the flattened cross-sectional view and the U-shaped cross-sectional view. The unfolded fabric is prepared based on the designed fabric parameters, and then each weft yarn is pulled and tightened, so as to bend and deform the unfolded fabric, and finally the overall preparation of the special-shaped three-dimensional fabric is achieved; at the same time, the present invention also performs a step-by-step design on the splicing area, so that during the deformation process, the warp yarns and weft yarns in the splicing area are connected to form an integral structure, the splicing gaps generated during the bending deformation process are eliminated, and the integrity of the product is improved; compared with the one-time close-size weaving forming, the preparation method of the special-shaped three-dimensional fabric of the present invention reduces the difficulty of process operation through two-time forming of weaving and deformation; in addition, the secondary deformation forming can reduce the dependence of the fabric on special weaving equipment, and the production of complex surface products can be completed under conventional equipment.

[0042] In this embodiment, the preset parameters include the total warp yarn density, the total number of warp yarn layers, the total weft yarn density and the total number of weft yarn layers of the special-shaped three-dimensional fabric.

[0043] In this embodiment, S21, according to the areas and area change rates of the central joint area C3, the side joint area B2 and the covering area A1 in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the total warp yarn density of the special-shaped three-dimensional fabric, the number of warp yarns, the warp yarn density and the warp yarn fineness in the central joint area C3, the side joint area B2 and the covering area A1 in the unfolded fabric are calculated, and the local area with a large area change rate is subjected to yarn addition processing;

[0044] S22, based on the total number of warp yarn layers in the special-shaped three-dimensional fabric, the number of warp yarn layers is designed according to the height correspondence between the central splicing area C3 and the side splicing area B2 in the U-shaped cross-sectional view and the flattened cross-sectional view; a stepped splicing area is designed on both side edges of the central splicing area C3 in the flattened cross-sectional view and the inner side edges of the side splicing area B2, and the number of warp yarn columns is designed according to the number of warp yarn layers and the angle of the splicing area of ​​the central splicing area C3 and the side splicing area B2 in the unfolded fabric, so as to obtain the warp yarn arrangement of the central splicing area C3 and the side splicing area B2 in the flattened cross-sectional view.

[0045] In this embodiment, S31, according to the height ratio of the side edge of the central joint area C3 and the side edge of the adjacent side joint area B2 in the flattened cross-sectional view, based on the total number of weft yarn layers of the special-shaped three-dimensional fabric, the number of weft yarn layers in the central joint area C3 and the side joint area B2 is determined;

[0046] S32, determining the weft yarn fineness and weft insertion structure in the central splicing area C3 and the side splicing area B2 according to the number of weft yarn layers in the central splicing area C3 and the side splicing area B2 and the thickness of the special-shaped three-dimensional fabric.

[0047] In this embodiment, S41, based on the design parameters obtained in S2 and S3 and the size of the flattened cross-sectional view, the unfolded fabric is prepared, and the three-dimensional fabric is bent and deformed with the symmetry axis of the central splicing area C3 as a reference;

[0048] S42, during the bending deformation process, the weft yarns described in S3 are pulled, tightened and arranged so that each weft yarn is straightly distributed in the central splicing area C3 and the side splicing area B2, until the two side edges of the central splicing area C3 are completely fitted with one side of the corresponding side splicing area B2, and the excess weft yarns are removed to complete the forming of the special-shaped three-dimensional fabric.

[0049] In this embodiment, the special-shaped three-dimensional fabric is one of a 2.5D structure, a 2.5D weft-inserted structure, and other variable-structure 2.5D structures.

[0050] In this embodiment, the symmetry plane of the central joint area C3 coincides with the symmetry plane of the U-shaped portion of the special-shaped three-dimensional fabric.

[0051] In this embodiment, before S4, a pressing plate having a length greater than that of the shaped three-dimensional fabric is prepared, and a plurality of single-row needles are used to fix the unfolded fabric to the upper surface of the pressing plate along the symmetry plane of the central splicing area C3 and along the thickness direction of the shaped three-dimensional fabric, and multiple bending deformations are performed with the pressing plate as a fixed reference.

[0052] In this embodiment, the distance between each single row of needles is 20-40 mm.

[0053] In this embodiment, the needle pitch of a single row of needles is 20-40 mm.

[0054] In this embodiment, in S2, yarn adding treatment is performed on the bottom of the central splicing area C3 with a large area change rate in the U-shaped cross-sectional view and the flattened cross-sectional view and the arc portion of the covering area A1, so that the warp yarn density is increased within 20% and the warp yarn fineness is increased to twice.

[0055] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the present invention provides an embodiment, the special-shaped three-dimensional fabric is a glass fiber three-dimensional fabric, having a U-shaped portion with a U-shaped cross-section, and a straight-edge groove is provided on the top of the U-shaped portion, wherein the thickness of the straight-edge regions on both sides of the U-shaped portion is 12-15 mm, the thickness of the arc region of the U-shaped portion is 25-30 mm, the width of the U-shaped portion, i.e., the width of the U-shaped cross-sectional view, is 600 mm, and the width of the unfolded fabric, i.e., the width of the flattened cross-sectional view, is 1200 mm, in the special-shaped three-dimensional fabric, each warp yarn is parallelly distributed along the length direction of the special-shaped three-dimensional fabric, and each weft yarn is arranged parallel to the outer edge of the U-shaped cross-sectional view; and the preparation method thereof comprises the following steps:

[0056] S1, draw a U-shaped cross-sectional view according to the U-shaped cross-sectional shape of the U-shaped portion, and offset a certain distance inward along the outer edge of the U-shaped cross-sectional view to obtain a first area dividing line 4, and the first area dividing line 4 and the outer edge of the U-shaped cross-sectional view are surrounded to form a covering area A1; connect the turning points on both sides of the first area dividing line 4 with the corresponding end points of the bottom edge of the straight-edge groove on the adjacent side to obtain a second area dividing line 5, and the two second area dividing lines 5, the first area dividing line 4 and the bottom edge of the straight-edge groove are surrounded to form a central splicing area C3, and each second area dividing line 5, the first area dividing line 4 and the bottom edge of the straight-edge groove are surrounded to form a central splicing area C3. The dividing line 4 and the side of the adjacent straight-edge groove are surrounded to form a side joint area B2, then the first area dividing line 4 and the second area dividing line 5 divide the U-shaped cross-sectional view into a central joint area C3 that is approximately isosceles trapezoidal, two side joint areas B2 that are right-angled trapezoids, and a strip-shaped covering area A1 that surrounds the two side joint areas B2, and the two waists of the central joint area C3 are respectively attached to the oblique sides of the two side joint areas B2; the U-shaped cross-sectional view is cut along the two second area dividing lines 5, and the covering area A1 and the side joint area B2 are flattened to obtain a flattened cross-sectional view;

[0057] S2, according to the area change rate of the central splicing area C3, the side splicing area B2 and the covering area A1 in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the preset parameters of the special-shaped three-dimensional fabric, the number of warp yarns, the density of warp yarns and the fineness of warp yarns in the central splicing area C3, the side splicing area B2 and the covering area A1 in the flattened cross-sectional view are designed;

[0058] S21, according to the area and area change rate of the central splicing area C3, the side splicing area B2 and the covering area A1 in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the total warp yarn density of the special-shaped three-dimensional fabric, the number of warp yarns, the warp yarn density and the warp yarn fineness in the central splicing area C3, the side splicing area B2 and the covering area A1 in the unfolded fabric are calculated, and the local area with a large area change rate is added with yarn; as shown in Table 1, the special-shaped three-dimensional fabric is a 2.5D weft insertion structure, and the area of ​​the central splicing area C3 is 6.1 cm 2 , the area of ​​the side joint area B2 is 4.5cm 2 , the preset parameters are 10 layers of warp yarns, 11 layers of weft yarns, warp density 10.0±0.2 strands / cm, weft density 4.0±0.1 strands / cm, and the warp yarn fineness is calculated to be 570tex, then 124 warp yarns are required in the central splicing area C3, and 90 warp yarns are required in the side splicing area B2; yarn is added locally to the middle position of the covering area A1, i.e., the bottom of the arc deformation area and the central splicing area C3, so that the local warp density is 12±0.2 strands / cm, and the local warp yarn fineness is increased to 570tex*2 ply;

[0059] S22, based on the total number of warp yarn layers of the special-shaped three-dimensional fabric, the number of warp yarn layers is designed according to the height correspondence between the central splicing area C3 and the side splicing area B2 in the U-shaped cross-sectional view and the flattened cross-sectional view; a stepped splicing area is designed on both sides of the central splicing area C3 in the flattened cross-sectional view and the inner side of the side splicing area B2, and the number of warp yarn rows is designed according to the number of warp yarn layers of the central splicing area C3 and the side splicing area B2 in the unfolded fabric and the angle of the splicing area, so as to obtain the central splicing area C3 in the flattened cross-sectional view. The warp yarn arrangement of the side stitching area B2; as shown in Table 1, the side stitching area B2 is a trapezoid with a length of 20mm and a height of 10mm after being unfolded. In the unfolded fabric, the splicing area in the side stitching area B2 can be designed as 10 steps with a width of 2mm and a height of 9-10mm; the central stitching area 3 is a trapezoid with a width of 10mm and a height of 20mm after being unfolded. In the unfolded fabric, the splicing area in the central stitching area 3 can be designed as 5 steps with a width of 2mm and a height of 7-20mm;

[0060] S3, according to the height ratio of the side of the central stitching area C3 and the side of the adjacent side stitching area B2 in the flattened cross-sectional view, determine the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2; based on the preset parameters of the special-shaped three-dimensional fabric and the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2, design the number of weft yarns and the weft insertion structure in the central stitching area C3 and the side stitching area B2 in the flattened cross-sectional view, wherein a single weft yarn horizontally passes through the one side stitching area B2, the central stitching area C3 and the other side stitching area B2 in sequence;

[0061] S31, according to the height ratio of the side of the central stitching area C3 and the side of the adjacent side stitching area B2 in the flattened cross-sectional view, based on the total number of weft yarn layers of the special-shaped three-dimensional fabric, determine the number of weft yarn layers in the central stitching area C3 and the side stitching area B2; in the flattened cross-sectional view, the height of the central stitching area C3 is 20 mm, and the height of the side stitching area B2 is 10 mm, so the number of weft yarn layers in the central stitching area C3 is calculated to be 20, the number of weft yarn layers in the side stitching area B2 is 10, and the ratio of the weft insertion layers in the two areas is 1:2;

[0062] S32, according to the number of weft yarn layers in the central splicing area C3 and the side splicing area B2 and the thickness of the special-shaped three-dimensional fabric, determine the weft yarn fineness and weft insertion structure in the central splicing area C3 and the side splicing area B2; the ratio of the number of weft insertion layers in the central splicing area C3 and the side splicing area B2 is 1:2, then according to the size parameters of the three-dimensional fabric and the number of warp and weft yarn layers, the fineness of each layer of weft yarn in the side splicing area B2 is calculated to be 570*2tex, the fineness of each layer of weft yarn in the central splicing area C3 is 570tex, and the weft insertion structure is to use 570tex fiber to reciprocate in the two areas, and the first 570tex weft yarn is sequentially introduced into the left side splicing area. The first layer of area B2, the first layer of the central splicing area C3 and the first layer of the right side splicing area B2, after folding back, the second 570tex weft yarn is sequentially introduced into the first layer of the right side splicing area B2, the second layer of the central splicing area C3 and the first layer of the left side splicing area B2; the third 570tex weft yarn is sequentially introduced into the second layer of the left side splicing area B2, the third layer of the central splicing area C3 and the second layer of the right side splicing area B2, after folding back, the fourth 570tex weft yarn is sequentially introduced into the second layer of the right side splicing area B2, the fourth layer of the central splicing area C3 and the second layer of the left side splicing area B2, and the above steps are repeated to complete the weft insertion of all weft yarns, such as Figure 2 , Figure 3 , Figure 4 As shown;

[0063] S4, based on the parameters obtained in S2 and S3, the unfolded fabric is prepared, and each weft yarn is pulled and tightened to make the unfolded fabric bend and deform until the two sides of the central splicing area C3 are completely fitted with one side of the corresponding side splicing area B2, thereby obtaining a special-shaped three-dimensional fabric;

[0064] S41, based on the design parameters obtained in S2 and S3 and the size of the flattened cross-sectional diagram, the unfolded fabric is prepared, and the three-dimensional fabric is bent and deformed with the symmetry axis of the central splicing area C3 as a reference; wherein, a pressing plate having a length greater than the length of the special-shaped three-dimensional fabric is first prepared, and the unfolded fabric is fixed to the upper surface of the pressing plate along the symmetry plane of the central splicing area C3 and the thickness direction of the special-shaped three-dimensional fabric using multiple single-row needles, with a needle pitch of 20-40 mm, and multiple bending deformations are performed with the pressing plate as a fixed reference

[0065] S42, during the bending deformation process, the weft yarns described in S3 are pulled, tightened and arranged, so that each weft yarn is distributed straight in the central splicing area C3 and the side splicing area B2, until the two side edges of the central splicing area C3 are completely fitted with the corresponding side of the side splicing area B2, and the excess weft yarns are removed to complete the forming of the special-shaped three-dimensional fabric; during the finishing process, the yarn ends of the folded weft yarns on both sides of the fabric are pulled outward along the fabric surface direction, so that the weft yarns in the side splicing area B2-central splicing area C3-side splicing area B2 are arranged straight during multiple deformations, and with multiple bending and finishing, the stepped splicing area in the side splicing area B2 is completely contacted and squeezed with the stepped splicing areas on both sides of the central splicing area C3, and the warp yarns and weft yarns in the splicing area are combined to complete the homogeneous bending deformation of the fabric.

[0066] Table 1 "U" shaped fabric parameters

[0067]

[0068] like Figure 6 As shown, the present invention further provides an embodiment, wherein the three-dimensional fabric comprises a support leg 1 and a support leg 2 arranged at an angle, the outer side of the connection between the support leg 1 and the support leg 2 is smoothly connected, and the inner side is connected by a plurality of straight edges. In this embodiment, the connection between the support leg 1 and the support leg 2 forms a U-shaped portion with a certain angle between the straight edge areas on both sides, and the preparation process thereof comprises the following steps:

[0069] S1, according to the U-shaped cross-section shape of the U-shaped part, draw Figure 6As shown in the cross-sectional view, the outer edge of the U-shaped cross-sectional view is offset inward by a certain distance to obtain a first area dividing line 4, and a covering area A1 is formed between the first area dividing line 4 and the outer edge of the U-shaped cross-sectional view; the turning points on both sides of the first area dividing line 4 are respectively connected with the corresponding end points of the bottom edge of the straight-edge groove on the adjacent side to obtain a second area dividing line 5, and the two second area dividing lines 5, the first area dividing line 4 and the bottom edge of the straight-edge groove are surrounded to form a central splicing area C3, and each second area dividing line 5, the first area dividing line 4 and the side edge of the adjacent straight-edge groove are surrounded to form a side splicing area B2; the U-shaped cross-sectional view is sheared along the two second area dividing lines 5, and the covering area A1 and the side splicing area B2 are flattened to obtain a flattened cross-sectional view;

[0070] S2, according to the area change rate of the central splicing area C3, the side splicing area B2 and the covering area A1 in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the preset parameters of the special-shaped three-dimensional fabric, the number of warp yarns, the density of warp yarns and the fineness of warp yarns in the central splicing area C3, the side splicing area B2 and the covering area A1 in the flattened cross-sectional view are designed;

[0071] S3, according to the height ratio of the side of the central stitching area C3 and the side of the adjacent side stitching area B2 in the flattened cross-sectional view, determine the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2; based on the preset parameters of the special-shaped three-dimensional fabric and the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2, design the number of weft yarns and the weft insertion structure in the central stitching area C3 and the side stitching area B2 in the flattened cross-sectional view, wherein a single weft yarn horizontally passes through the one side stitching area B2, the central stitching area C3 and the other side stitching area B2 in sequence;

[0072] S4, based on the parameters obtained in S2 and S3, an unfolded fabric is prepared, and each weft yarn is pulled, tightened and arranged to make the unfolded fabric bend and deform until the two side edges of the central splicing area C3 are completely fitted with one side of the corresponding side splicing area B2, thereby obtaining a special-shaped three-dimensional fabric.

[0073] like Figure 7 As shown, the present invention also provides an embodiment, wherein the three-dimensional fabric includes a flat plate structure and a convex structure distributed at intervals, and the convex structure can be regarded as Figure 1 A rectangular portion is spliced ​​into a straight-edge groove of the structure shown, and the preparation process includes the following steps:

[0074] S1, according to the U-shaped cross-section shape of the U-shaped part, draw Figure 7As shown in the cross-sectional view, the outer edge of the U-shaped cross-sectional view is offset inward by a certain distance to obtain a first area dividing line 4, and a covering area A1 is formed between the first area dividing line 4 and the outer edge of the U-shaped cross-sectional view; the turning points on both sides of the first area dividing line 4 are respectively connected with the corresponding end points of the bottom edge of the straight-edge groove on the adjacent side to obtain a second area dividing line 5, and the two second area dividing lines 5, the first area dividing line 4 and the bottom edge of the straight-edge groove are surrounded to form a central splicing area C3, and each second area dividing line 5, the first area dividing line 4 and the side edge of the adjacent straight-edge groove are surrounded to form a side splicing area B2; the U-shaped cross-sectional view is sheared along the two second area dividing lines 5, and the covering area A1 and the side splicing area B2 are flattened to obtain a flattened cross-sectional view;

[0075] S2, according to the area change rate of the central splicing area C3, the side splicing area B2 and the covering area A1 in the U-shaped cross-sectional view and the flattened cross-sectional view, based on the preset parameters of the special-shaped three-dimensional fabric, the number of warp yarns, the density of warp yarns and the fineness of warp yarns in the central splicing area C3, the side splicing area B2 and the covering area A1 in the flattened cross-sectional view are designed;

[0076] S3, according to the height ratio of the side of the central stitching area C3 and the side of the adjacent side stitching area B2 in the flattened cross-sectional view, determine the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2; based on the preset parameters of the special-shaped three-dimensional fabric and the ratio of the number of weft yarn layers in the central stitching area C3 and the side stitching area B2, design the number of weft yarns and the weft insertion structure in the central stitching area C3 and the side stitching area B2 in the flattened cross-sectional view, wherein a single weft yarn horizontally passes through the one side stitching area B2, the central stitching area C3 and the other side stitching area B2 in sequence;

[0077] S4, based on the parameters obtained in S2 and S3, an unfolded fabric is prepared, and each weft yarn is pulled, tightened and arranged to make the unfolded fabric bend and deform until the two side edges of the central splicing area C3 are completely fitted with one side of the corresponding side splicing area B2, thereby obtaining a special-shaped three-dimensional fabric.

[0078] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a special-shaped three-dimensional fabric, characterized in that: The special-shaped three-dimensional fabric has a U-shaped portion with a U-shaped cross section, and a straight-edge groove is provided on the top of the U-shaped portion. The preparation method comprises the following steps: S1, a U-shaped cross-sectional view is drawn according to the U-shaped cross-sectional shape of the U-shaped portion, and a first region dividing line (4) is offset inwardly by a certain distance along the outer edge of the U-shaped cross-sectional view to obtain a first region dividing line (4), and a covering region A (1) is formed between the first region dividing line (4) and the outer edge of the U-shaped cross-sectional view; the turning points on both sides of the first region dividing line (4) are respectively connected to the corresponding end points of the bottom edge of the straight-edge groove on one side to obtain a second region dividing line (5), and the two second region dividing lines (5), the first region dividing line (4) and the bottom edge of the straight-edge groove are formed to form a central splicing region C (3), and each second region dividing line (5), the first region dividing line (4) and the side edge of the adjacent straight-edge groove are formed to form a side splicing region B (2); the U-shaped cross-sectional view is cut along the two second region dividing lines (5), and the covering region A (1) and the side splicing region B (2) are flattened to obtain a flattened cross-sectional view; S2, relative to the U-shaped cross-sectional view, calculate the area change rate of the central joint area C (3), the side joint area B (2) and the covering area A (1) in the flattened cross-sectional view, and design the number of warp yarns, the density of warp yarns and the fineness of warp yarns in the central joint area C (3), the side joint area B (2) and the covering area A (1) in the flattened cross-sectional view based on the preset parameters and area change rate of the special-shaped three-dimensional fabric; S3, determining the weft yarn layer ratio of the central splicing area C(3) to the side splicing area B(2) according to the height ratio of the side edge of the central splicing area C(3) to the side splicing area B(2) in the flattened cross-sectional view; designing the weft yarn ply number and weft insertion structure in the central splicing area C(3) and the side splicing area B(2) in the flattened cross-sectional view based on the preset parameters of the special-shaped three-dimensional fabric and the weft yarn layer ratio of the central splicing area C(3) to the side splicing area B(2), wherein a single weft yarn horizontally passes through the one side splicing area B(2), the central splicing area C(3) and the other side splicing area B(2) in sequence; S4, based on the parameters obtained in S2 and S3, an unfolded fabric is prepared, and each weft yarn is pulled and tightened to make the unfolded fabric bend and deform until the two side edges of the central splicing area C (3) are completely fitted with one side of the corresponding side splicing area B (2) to obtain a special-shaped three-dimensional fabric.

2. The method for preparing a special-shaped three-dimensional fabric according to claim 1, characterized in that: The preset parameters include the total warp yarn density, the total warp yarn layer number, the total weft yarn density and the total weft yarn layer number of the special-shaped three-dimensional fabric.

3. The method for preparing a special-shaped three-dimensional fabric according to claim 2, characterized in that: S21, according to the areas and area change rates of the central joint area C(3), the side joint area B(2) and the covering area A(1) in the U-shaped cross-sectional view and the flattened cross-sectional view, and based on the total warp yarn density of the special-shaped three-dimensional fabric, the number of warp yarns, the warp yarn density and the warp yarn fineness in the central joint area C(3), the side joint area B(2) and the covering area A(1) in the unfolded fabric are calculated, and yarn addition processing is performed on the local area with a large area change rate; S22, based on the total number of warp yarn layers of the special-shaped three-dimensional fabric, the number of warp yarn layers is designed according to the height correspondence between the central splicing area C(3) and the side splicing area B(2) in the U-shaped cross-sectional view and the flattened cross-sectional view; a stepped splicing area is designed on the two side edges of the central splicing area C(3) in the flattened cross-sectional view and the inner side edges of the side splicing area B(2); the number of warp yarn columns is designed according to the number of warp yarn layers and the angle of the splicing area of ​​the central splicing area C(3) and the side splicing area B(2) in the unfolded fabric, and the warp yarn arrangement of the central splicing area C(3) and the side splicing area B(2) in the flattened cross-sectional view is obtained.

4. The method for preparing a special-shaped three-dimensional fabric according to claim 3, characterized in that: S31, determining the number of weft yarn layers in the central joint area C (3) and the side joint area B (2) according to the height ratio of the side edge of the central joint area C (3) and the side edge of the adjacent side joint area B (2) in the flattened cross-sectional view and based on the total number of weft yarn layers of the shaped three-dimensional fabric; S32, determining the weft yarn fineness and weft insertion structure in the central splicing area C(3) and the side splicing area B(2) according to the number of weft yarn layers in the central splicing area C(3) and the side splicing area B(2) and the thickness of the shaped three-dimensional fabric.

5. The method for preparing a special-shaped three-dimensional fabric according to claim 4, characterized in that: S41, preparing an unfolded fabric based on the design parameters obtained in S2 and S3 and the size of the flattened cross-sectional image, and bending and deforming the three-dimensional fabric with the symmetry axis of the central splicing area C(3) as a reference; S42, during the bending deformation process, the weft yarns described in S3 are pulled, tightened and arranged so that each weft yarn is straightly distributed in the central splicing area C (3) and the side splicing area B (2), until the two side edges of the central splicing area C (3) are completely fitted with the corresponding side of the side splicing area B (2), and the excess weft yarns are removed to complete the forming of the special-shaped three-dimensional fabric.

6. The method for preparing a special-shaped three-dimensional fabric according to claim 5, characterized in that: The special-shaped three-dimensional fabric is one of the 2.5D structure, 2.5D weft-inserted structure and other variable-structure 2.5D structures.

7. The method for preparing a special-shaped three-dimensional fabric according to claim 6, characterized in that: The symmetry plane of the central splicing area C (3) coincides with the symmetry plane of the U-shaped portion of the special-shaped three-dimensional fabric.

8. The method for preparing a special-shaped three-dimensional fabric according to claim 7, characterized in that: Before S4, a pressing plate having a length greater than that of the shaped three-dimensional fabric is prepared, and the unfolded fabric is fixed to the upper surface of the pressing plate along the symmetry plane of the central splicing area C(3) and the thickness direction of the shaped three-dimensional fabric using multiple single-row needles, and multiple bending deformations are performed with the pressing plate as a fixed reference.

9. The method for preparing a special-shaped three-dimensional fabric according to claim 8, characterized in that: The distance between each single row of needles is 20-40mm.

10. The method for preparing a special-shaped three-dimensional fabric according to claim 9, characterized in that: In S2, yarn is added to the bottom of the central splicing area C(3) and the arc portion of the covering area A(1) where the area change rate in the U-shaped cross-section and the flattened cross-section is large, so that the warp yarn density is increased by less than 20% and the warp yarn fineness is increased to twice.

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