A method of introducing warp and weft yarns in a three-dimensional woven fabric and a three-dimensional woven fabric

Abstract

The application discloses a method for introducing normal yarns and weft yarns in three-dimensional woven fabric and three-dimensional woven fabric, and belongs to the field of three-dimensional fabric weaving. The method comprises the following steps: in a three-dimensional four-step weaving process, after a standard cycle is completed, without increasing the total number of yarns, the normal yarns of the current pattern are introduced by moving the yarns on the thickest outermost moving spindles to pass through each row; the weft yarns of the current pattern are introduced by moving the yarns on the widest outermost moving spindles or the yarns on a certain moving spindle in the circumferential direction to pass through each column; and the next standard cycle is carried out after the normal yarns and the weft yarns are introduced. The method has extremely high designability, so that the continuity and structural integrity of the three-dimensional fabric can be ensured; the interlayer connection of the fabric can be enhanced, and the flatness of the normal yarns and the weft yarns in the fabric can be effectively improved, so that the mechanical properties of the composite material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for introducing normal yarns and weft yarns in three-dimensional woven fabric and three-dimensional woven fabric, belonging to the field of three-dimensional fabric weaving. BACKGROUND

[0002] Textile composite material is a high-level form of fiber reinforced composite material, which is obtained by weaving the reinforcing fibers into two-dimensional or three-dimensional textile reinforcing structure through textile processing method, and then combined with the matrix material. It has many advantages such as tight interlaced structure, good integrity, excellent mechanical properties, etc. The development of aviation and aerospace industry promotes the research of textile composite material, and its application field is expanding, which plays an increasingly important role in the fields of aviation, aerospace, construction, fishing, sports, military, etc. Through the method of weaving, the fiber yarns are processed into three-dimensional textile structure according to certain interlacing rules, so as to become a flexible fiber collection with certain shape and internal structure, which is called three-dimensional woven fabric.

[0003] Three-dimensional four-step weaving represents the mainstream of three-dimensional weaving. Due to the expanding application field, higher requirements are put forward for composite materials. In order to improve the axial performance of three-dimensional woven fabric, axial straight yarns are added on the basis of three-dimensional four-direction; in order to improve the performance in the plane of three-dimensional woven fabric, normal straight yarns and weft straight yarns are added on the basis of three-dimensional four-direction. More and more researches on the structure, weaving method and material performance of three-dimensional fabric are carried out by researchers, but the research on the method of adding normal yarns and weft yarns to three-dimensional woven fabric is relatively insufficient. The existing yarn adding method is to put the yarn on the yarn storage rod into the fabric layer by layer and column by column manually. The existing yarn adding method has the following shortcomings:

[0004] ①The flatness of the normal yarns and weft yarns added into the fabric is difficult to control;

[0005] ②The length of the normal yarns and weft yarns added into the fabric cannot be controlled;

[0006] ③The designability is poor;

[0007] ④The weaving process of the normal yarns and weft yarns added into the fabric is not tensioned, which is not conducive to controlling the shape of the fabric;

[0008] ⑤The operation method is low in efficiency, time-consuming and laborious, and prone to errors. SUMMARY

[0009] In order to solve the above problems, the present application provides a method for introducing normal yarns and weft yarns in three-dimensional woven fabric, which can realize the overall weaving of the special-shaped fabric of three-dimensional weaving by introducing normal yarns and weft yarns with tension of main body movement yarns, and the method is simple and has wide applicability. The technical scheme adopted by the present application is as follows:

[0010] A method for introducing normal yarns and weft yarns in a three-dimensional woven fabric, in a three-dimensional four-step weaving process, after a standard cycle is completed, without increasing the total number of yarns: introducing normal yarns by moving the yarn on the outermost motion spindle in the thickness direction to pass through each row to achieve the current pattern of normal yarns; introducing weft yarns by moving the yarn on the outermost motion spindle in the width direction or the yarn on a certain motion spindle in the circumferential direction to pass through each column to achieve the current pattern of weft yarns; after introducing the normal yarns and weft yarns, the next standard cycle is performed.

[0011] Using the above method, the frequency of adding normal yarns and weft yarns is one standard cycle, according to the performance requirements of the fabric and the motion law of the weaving bundle, without changing the motion law of the weaving bundle inside the fabric, the number, angle and arrangement of the normal yarns and / or weft yarns to be added can be flexibly designed, and the introduction of normal yarns and / or weft yarns in various profile three-dimensional fabrics such as plate-shaped fabric and conical tube-shaped fabric can be achieved.

[0012] Further, the three-dimensional woven fabric is a cross-section ring-shaped or non-ring-shaped fabric formed by three-dimensional four-step weaving.

[0013] Further, the ring-shaped fabric includes a circular ring-shaped, cylindrical, conical or special-shaped three-dimensional woven fabric.

[0014] Further, the non-ring-shaped fabric includes a three-dimensional woven fabric with a cross-section in the shape of I, L, T or U.

[0015] Further, the method for introducing normal yarns includes the following steps connected in sequence:

[0016] (1) After a standard cycle of three-dimensional four-step weaving is completed, the arrangement of the outermost motion spindles is one in every other column, and the two outermost rows of motion spindles are staggered;

[0017] (2) The yarn on the uppermost motion spindle is passed downward through each row according to the set introduction angle to be hung on the lowermost motion spindle, and the yarn on the motion spindle receiving the yarn is passed upward through each row according to the same introduction angle to be hung on the motion spindle giving out the yarn;

[0018] (3) Continue the next standard cycle of three-dimensional four-step weaving;

[0019] (4) Repeat steps (2) and (3) until the fabric reaches the target size.

[0020] Further, the introduction angle is 0-45°, and the introduction angle refers to the angle between the introduced normal yarns and the thickness direction of the fabric.

[0021] Furthermore, when the three-dimensional woven fabric is a non-circular fabric, the method for introducing the weft yarn includes the following steps connected in sequence:

[0022] (1) After the standard cycle of the three-dimensional four-step method is completed, the arrangement of the outermost moving spindle is as follows: one spindle every other column, one spindle every other row, and the two rows of moving spindles in the outermost layer are arranged alternately, and the two columns of moving spindles in the outermost layer are arranged alternately.

[0023] (2) The yarn on the odd-numbered column of the outermost moving spindles passes through each column along the fabric width direction and is hung on the even-numbered column of the outermost moving spindles, so that the yarn on the receiving moving spindle passes through each column along the fabric width direction and is hung on the giving moving spindle.

[0024] (3) Continue to the next standard cycle of the three-dimensional four-step method;

[0025] (4) Repeat steps (2) and (3) until the fabric reaches the target size.

[0026] Furthermore, when the three-dimensional woven fabric is a loop fabric, the method for introducing the weft yarn includes the following steps connected in sequence:

[0027] (1) After the standard cycle of the three-dimensional four-step method is completed, the outermost layer of moving spindles is arranged as follows: one spindle every other column, and the two rows of moving spindles in the outermost layer are arranged alternately.

[0028] (2) After wrapping the yarn on any one of the moving spindles in each row around the circumference of the layer, it is still hung on the moving spindle;

[0029] (3) Continue to the next standard cycle of the three-dimensional four-step method;

[0030] (4) Repeat steps (2) and (3) until the fabric reaches the target size.

[0031] Furthermore, when the yarn used for weaving is multi-ply, a portion of the yarn can be selected for movement, while the remaining yarns maintain their original trajectory. This method improves the design flexibility of incorporating normal and weft yarns.

[0032] The present invention also provides a three-dimensional woven fabric woven using any of the above methods.

[0033] The beneficial effects of this invention are:

[0034] 1. The three-dimensional fabric manufactured by the method of the present invention can solve technical problems such as special local load-bearing requirements, complex shape, and overall weaving and molding of fabric. The prepared three-dimensional fabric has good integrity and greatly improved mechanical properties, thereby improving the overall mechanical properties of composite materials.

[0035] 2. This method has extremely high designability, which can ensure the continuity and structural integrity of three-dimensional fabrics; it makes the interlayer connection of three-dimensional fabrics deeper and the anti-delamination ability stronger, thereby improving the mechanical properties of composite materials.

[0036] 3. This invention utilizes existing knitting yarns for operation, without the need for additional normal and weft yarn systems. Its operation method is simple and widely adaptable. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the 3D quartz fiber plate obtained in Embodiment 1 of the present invention. In the figure, the arrow indicates the weaving direction.

[0038] Figure 2 for Figure 1 A schematic diagram of the yarn spindle arrangement after a certain cycle has ended.

[0039] Figure 3 for Figure 2 A schematic diagram showing the yarn shifting direction for each column where the normal yarn is added.

[0040] Figure 4 for Figure 2 A schematic diagram showing the direction of yarn transfer when adding weft yarns in each layer.

[0041] Figure 5 This is a schematic diagram of the 3D carbon fiber plate obtained in Embodiment 2 of the present invention. In the figure, the arrow indicates the weaving direction.

[0042] Figure 6 for Figure 5 A schematic diagram of the yarn spindle arrangement after a certain cycle has ended.

[0043] Figure 7 for Figure 6 A schematic diagram showing the direction of yarn transfer with an angled normal yarn added.

[0044] Figure 8 This is a schematic diagram of the carbon fiber tube obtained in Embodiment 3 of the present invention. In the figure, the arrow indicates the weaving direction.

[0045] Figure 9 for Figure 8 Schematic diagram of the initial yarn spindle arrangement in the circular tube.

[0046] Figure 10 for Figure 9 A schematic diagram showing the yarn transfer direction for each column where the normal yarn is added.

[0047] Figure 11 for Figure 9 A schematic diagram showing the direction of yarn transfer when adding weft yarn to each layer.

[0048] Figure 12The schematic diagram of the quartz fiber round tube obtained in Embodiment 4 of the present application is shown in the figure, and the arrow direction is the weaving direction.

[0049] Figure 13 For Figure 12 The schematic diagram of the initial yarn spindle arrangement of the round tube.

[0050] Figure 14 For Figure 13 The schematic diagram of the yarn shifting direction of each column with the addition of the angle normal yarn. DETAILED DESCRIPTION

[0051] In order to better understand the present application, the content of the present application is further illustrated below in combination with the embodiments, but the content of the present application is not limited to the following embodiments only.

[0052] In the embodiments, Tex refers to the fineness of the weaving yarn bundle, that is, the weight of the yarn bundle per kilometer.

[0053] In the embodiments, the number of yarns refers to the number of spindles, and one yarn can be a plurality of strands.

[0054] Embodiment 1

[0055] The method of the present application is used to weave the equal-thickness rectangular plate shown in Figure 1 The fabric size is: length 200㎜×width 100㎜×thickness 5mm. The weaving is started from the cross section at one end of the rectangular plate as the reference cross section, and the forming direction of the weaving is along the length direction of the rectangle, as shown by the arrow direction in Figure 1 .

[0056] In this embodiment, a three-dimensional five-directional weaving structure is adopted, and 195Tex quartz fiber is selected for weaving, 2 strands of moving yarns and 2 strands of stationary yarns, the parent direction repeat is 52mm / 10 repeats, the circumferential direction repeat is 25mm / 10 repeats, the fiber volume fraction is 52%, among which the weft yarn volume fraction is 4.7% and the normal yarn volume fraction is 2.6%. The number of moving yarns required for the reference cross section is 640, which is arranged in 8 layers and 80 columns; the number of stationary yarns required is 553, which is arranged in 7 layers and 79 columns.

[0057] The method of adding the normal yarn and the weft yarn is described in detail by taking one weaving cycle of the plate as an example, and the steps are as follows:

[0058] (1) Refer to Figure 2 , Figure 2 The schematic diagram of the yarn spindle arrangement after the end of a cycle of the plate is shown in the figure, and 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are the outermost yarns of the weaving yarns of each column, which are arranged in a one-by-one manner on the same side of the plate, and A, B, C, D, E, F, G, and H are the outermost yarns of the weaving yarns of each layer, which are arranged in a one-by-one manner on the same side of the plate.

[0059] (2) See Figure 3 When adding a normal yarn, the yarn on spindle 1 is moved along the column to spindle 2, thus introducing a normal yarn into that column. Similarly, the original yarn on spindle 2 is moved along the column to spindle 3, and so on, introducing a normal yarn into each column. Finally, a yarn is added to the first spindle, and a yarn is removed from the last spindle to ensure the balance of the total number of yarns.

[0060] (3) See Figure 4 When adding weft yarn, the yarn on spindle A is moved along the layer to spindle B, thus introducing a weft yarn into that layer. Similarly, the original yarn on spindle B is moved along the layer to spindle C, and so on, introducing weft yarn into each layer. Finally, a yarn is added to the first spindle, and a yarn is removed from the last spindle to ensure a balance in the total number of yarns.

[0061] (4) After the addition of normal yarn and weft yarn is completed, a knitting cycle is performed.

[0062] Repeat the above steps until the weaving is complete. For each section of the resulting pattern, add both normal and weft yarns.

[0063] In existing three-dimensional weaving processes, the weaving involves adding normal and weft yarns. This is achieved using a separate spool of yarn, where the yarns on the spool are wound into the fabric layer by layer to form the normal (weft) yarns. The spool is not under tension, making precise control of this process difficult. The resulting normal (weft) yarns are prone to bending within the fabric, leading to low-density defects. Additionally, the fabric surface will have numerous fuzzy edges, affecting its appearance and neatness.

[0064] Fabrics woven using the method of this invention have normal and weft yarns that participate in the weaving process and are under tension throughout the entire weaving process. There is no bending of the normal (weft) yarns, and the outer surface of the fabric is free of fuzz, maintaining the continuity of the woven yarns and increasing the interlayer connection of the yarns, effectively improving the fabric's anti-delamination ability.

[0065] Example 2

[0066] Weaving using the method of this invention, such as Figure 5 The uniformly thick rectangular panel shown has fabric dimensions of 200mm (length) × 100mm (width) × 6mm (thickness). Weaving begins with one end of the rectangular panel as the reference section, and the weaving direction follows the length of the rectangle, as shown below. Figure 1 The direction indicated by the middle arrow.

[0067] This embodiment adopts three-dimensional five-directional weaving structure, selects 198Tex carbon fiber to weave, 2 strands of dynamic yarn are plied, 2 strands of static yarn are plied, the mother direction repeat is 58mm / 10 repeats, the circumferential direction repeat is 28mm / 10 repeats, the fiber volume fraction is 53%, wherein the weft yarn volume fraction is 4.9%, the normal yarn volume fraction is 3.8%. The required dynamic yarn number of the reference cross section design is 490, which is arranged into 70 columns in 8 layers; the required static yarn number is 414, which is arranged into 69 columns in 7 layers.

[0068] The method of adding 45 degree normal yarn and 45 degree weft yarn is described in detail by taking one weaving cycle of the plate as an example, and the steps are as follows:

[0069] (1) refer to Figure 6 , Figure 6 Fig. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 are the outermost yarns of each column of weaving yarn, which are arranged in a staggered manner on the same side of the plate, and A, B, C, D, E, F, G, H are the outermost yarns of each layer of weaving yarn, which are arranged in a staggered manner on the same side of the plate.

[0070] (2) refer to Figure 7 When adding 45 degree normal yarn, the yarn on the spindle 1 is sequentially moved to the spindle 6 by 4 columns, so that a normal yarn with a +45 degree angle with the outer boundary of the plate is introduced into the plate fabric. Similarly, the yarn on the spindle 2 is sequentially moved to the spindle 7 by 4 columns, so that a normal yarn with a -45 degree angle with the outer boundary of the plate is introduced into the plate fabric. In this way, the ±45 normal yarns of the main part of the plate are introduced. The edge part of the plate is moved in a cross manner, and the specific operation is to sequentially move the yarn on the spindle 6 to the spindle A by column, and sequentially move the yarn on the spindle 7 to the spindle G by column, and sequentially move the yarn on the spindle 7 to the spindle G by column, and sequentially move the yarn on the spindle 7 to the spindle G by column. In this way, the ±45 normal yarns of the edge part of the plate are introduced. Finally, one yarn is added to the left spindle and one yarn is removed from the right spindle to ensure the balance of the total number of yarns. After the operation of adding ±45 normal yarns is completed, one weaving motion cycle is performed.

[0071] (3) repeat the above steps until the weaving is completed. The obtained plate adds ±45 normal yarns to each repeat.

[0072] In the existing three-dimensional weaving process, this operation of adding ±45 normal yarns cannot be realized.

[0073] The fabric woven by the method of the present application has ±45 normal yarns which are normal dynamic yarns participating in weaving, and the ±45 normal yarns have tension throughout the weaving process, and there is no bending phenomenon of the normal (weft) yarn, and there is no fuzz on the outer surface of the fabric, the continuity of the weaving yarn is maintained, and the interlayer connection of the yarn is increased, and the anti-delamination ability of the fabric is effectively improved.

[0074] Example 3

[0075] Weaving using the method of this invention, such as Figure 8 The cylindrical component shown has an inner diameter of φ80mm, a height of 200mm, and a wall thickness of 10mm. Weaving begins with one end cross-section as the reference section, and the weaving direction is along the height of the cylinder, as shown below. Figure 8 The direction indicated by the middle arrow.

[0076] This embodiment employs a three-dimensional five-directional weaving structure, using T300-3K fiber. The moving yarns are 3-ply twisted together, and the stationary yarns are also 3-ply twisted together. The mother-direction pattern interval is 87mm / 10 patterns, and the circumferential pattern interval is 59mm / 10 patterns. The fiber volume fraction is 54.4%, with the weft yarn volume fraction at 5.5% and the normal yarn volume fraction at 4.3%. The baseline cross-section design requires 1908 moving yarns, arranged in 18 layers along a circular ring in 106 columns; and 1696 stationary yarns, arranged in 16 layers along a circular ring in 106 columns.

[0077] The method of adding normal and weft yarns in a circular loop is explained in detail using a knitting cycle diagram. The steps are as follows:

[0078] (1) See Figure 9 , Figure 9 This is a schematic diagram of the yarn arrangement after a certain cycle of the ring. In the diagram, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are the outermost and innermost yarns of each column of braided yarn. They are arranged in an alternating manner on the same side of the ring. In the diagram, A, B, C, D, and E are any yarns in each layer of braided yarn.

[0079] (2) See Figure 10 When adding a normal yarn, the yarn on spindle 1 is moved along the column to spindle 2, thus introducing a normal yarn into that column. Similarly, the original yarn on spindle 2 is moved along the column to spindle 3, and so on, introducing a normal yarn into each column.

[0080] (3) See Figure 11 When adding weft yarn, the yarn on spindle A is wrapped around the layer and then hung on the original spindle A, thus introducing a weft yarn into that layer. Similarly, the yarn on spindle B is wrapped around the layer and then hung on the original spindle B, and so on, introducing a weft yarn into each layer. After the addition of normal and weft yarns are completed, one knitting cycle is performed.

[0081] (4) Repeat the above steps until the weaving is complete. Add normal and weft yarns to each section of the resulting cylinder.

[0082] In the prior art three-dimensional weaving process, the weaving realizes cylinder plus normal yarn and plus weft yarn, and uses an additional shaft yarn to wind the yarn on the bobbin into the weaving fabric in rows (layers) to form the normal (weft) yarn, the bobbin is not under tension, the operation precision control is difficult, the formed normal (weft) yarn is easy to bend in the fabric, and low density defects are generated. At the same time, there are a large number of fluffs on the surface of the fabric, which affects the appearance neatness.

[0083] The cylinder fabric woven by the method of the application has normal yarns of normal (weft) yarn and weft yarn, which are always under tension in the whole weaving process, and there is no bending phenomenon of the normal (weft) yarn, and there is no fluff on the outer surface of the fabric, the continuity of the woven yarn is maintained, the interlayer connection of the yarn is increased, and the anti-delamination capability of the fabric is effectively improved.

[0084] Example 4

[0085] The cylinder workpiece woven by the method of the application has normal yarns of normal (weft) yarn and weft yarn, which are always under tension in the whole weaving process, and there is no bending phenomenon of the normal (weft) yarn, and there is no fluff on the outer surface of the fabric, the continuity of the woven yarn is maintained, the interlayer connection of the yarn is increased, and the anti-delamination capability of the fabric is effectively improved. Figure 12 The cylinder workpiece woven by the method of the application has normal yarns of normal (weft) yarn and weft yarn, which are always under tension in the whole weaving process, and there is no bending phenomenon of the normal (weft) yarn, and there is no fluff on the outer surface of the fabric, the continuity of the woven yarn is maintained, the interlayer connection of the yarn is increased, and the anti-delamination capability of the fabric is effectively improved. Figure 10 The cylinder workpiece woven by the method of the application has normal yarns of normal (weft) yarn and weft yarn, which are always under tension in the whole weaving process, and there is no bending phenomenon of the normal (weft) yarn, and there is no fluff on the outer surface of the fabric, the continuity of the woven yarn is maintained, the interlayer connection of the yarn is increased, and the anti-delamination capability of the fabric is effectively improved.

[0086] This embodiment adopts a three-dimensional five-directional weaving structure, and quartz yarns with a fineness of 195TEX are selected for weaving. The moving yarns are two-ply, the non-moving yarns are two-ply, the meridian flower pitch is 62mm / 10 flowers, the circumferential flower pitch is 40mm / 10 flowers, the fiber volume fraction is 54.9%, the weft yarn volume fraction is 5.2%, and the angle normal yarn volume fraction is 4.2%. The number of yarns required for the reference cross section is 1704, which is arranged in 142 columns in 12 layers along the circular ring; the number of non-moving yarns required is 1420, which is arranged in 142 columns in 10 layers along the circular ring.

[0087] The method of the circular ring plus angle normal yarn and plus weft yarn is described in detail by taking one weaving cycle as an example, and the steps are as follows:

[0088] (1) Refer to Figure 13 , Figure 13 for the yarn spindle arrangement diagram after a cycle of the circular ring, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are the outermost and innermost yarns of each column of weaving yarn, which are arranged in a staggered manner on the same side of the circular ring, A, B, C, D, and E are any one yarn in each layer of weaving yarn.

[0089] (2) Refer to Figure 14When adding the normal yarn, the knitting yarn on the spindle 1 is orderly moved through the fabric to the spindle 4, thus a normal yarn with a positive angle is introduced, the angle varies according to the number of the crossed columns. Similarly, the yarn on the spindle 2 is orderly moved through the fabric to the spindle 5, thus a normal yarn with a negative angle is introduced, the angle varies according to the number of the crossed columns. In this way, the whole fabric is introduced with normal yarns with positive and negative angles. When adding the weft yarn, the method is the same as that in the embodiment 3. After the addition of the normal yarn and the weft yarn, a knitting movement cycle is performed.

[0090] (3) Repeat the above steps until the knitting is completed. The obtained cylinder is added with the normal yarn with an angle and the weft yarn at each stitch.

[0091] In the prior art three-dimensional knitting process, the cylinder cannot be added with the normal yarn with an angle.

[0092] The cylinder fabric knitted by the method of the present application is added with the normal yarn and the weft yarn which are the dynamic yarns normally participating in the knitting, and the normal (weft) yarn has tension throughout the whole knitting process, and the bending of the normal (weft) yarn does not exist, and the fabric outer surface does not have the burr, the continuity of the knitting yarn is maintained, and the interlayer connection of the yarn is increased, and the anti-delamination ability of the fabric can be effectively improved.

Claims

1. A method for introducing normal and weft yarns into a three-dimensional woven fabric, characterized in that, The steps are as follows: (1) When the cross-section of the three-dimensional woven fabric is non-circular, after a standard cycle of the three-dimensional four-step method is completed, the arrangement of the outermost layer of moving yarn spindles is: one spindle every other column, one spindle every other row, and the two rows of moving yarn spindles in the outermost layer are arranged alternately, and the two columns of moving yarn spindles in the outermost layer are arranged alternately. (2) The yarn on the uppermost moving spindle passes down through each row at the set introduction angle and is hung on the lowermost moving spindle. The yarn on the receiving moving spindle passes up through each row at the same introduction angle and is hung on the next uppermost moving spindle that gives yarn. The yarn moves in this way to introduce all normal yarns. A yarn is added to the spindle at the beginning of the yarn movement, and a yarn is removed from the spindle at the end of the yarn movement to ensure the balance of the total number of yarns. (3) The yarn on the odd-numbered column of the outermost moving spindle passes through each column along the fabric width direction and is hung on the even-numbered column of the outermost moving spindle. The yarn on the receiving moving spindle passes through each column along the fabric width direction and is hung on the next odd-numbered moving spindle that gives the yarn. The yarn moves in this way to introduce all the weft yarns. A yarn is added to the spindle at the beginning of the yarn movement and a yarn is removed from the spindle at the end of the yarn movement to ensure the balance of the total number of yarns. (4) Continue to the next standard cycle of the three-dimensional four-step method; (5) Repeat steps (1) to (4) until the fabric reaches the target size.

2. The method for introducing normal and weft yarns into a three-dimensional woven fabric according to claim 1, characterized in that, The introduction angle of the normal yarn is 0 to 45°. The introduction angle refers to the angle between the introduced normal yarn and the thickness direction of the fabric.

3. The method for introducing normal and weft yarns into a three-dimensional woven fabric according to claim 1, characterized in that, The non-circular cross-section includes I-shaped, L-shaped, T-shaped, or U-shaped.

4. A three-dimensional woven fabric prepared by the method according to any one of claims 1 to 3.

5. A method for introducing normal and weft yarns in a three-dimensional woven fabric, characterized in that, The steps are as follows: (1) When the three-dimensional woven fabric is a ring fabric, after a standard cycle of the three-dimensional four-step method is completed, the arrangement of its outermost layer of moving yarn spindles is: one spindle every other column, and the two rows of moving yarn spindles in the outermost layer are arranged alternately. (2) The yarn on the innermost layer of moving spindles passes down through each row at the set introduction angle and is hung on the outermost layer of moving spindles. The yarn on the receiving yarn moving spindle passes inward through each row at the same introduction angle and is hung on the innermost layer of the next yarn-giving moving spindle. The yarn moves in this way to introduce all normal yarns. (3) After the yarn on any one of the moving spindles in each row is wrapped around the circumference of the layer, it is still hung on the moving spindle. The yarn moves in this way to introduce all the weft yarns. (4) Continue to the next standard cycle of the three-dimensional four-step method; (5) Repeat steps (1) to (4) until the fabric reaches the target size.

6. The method for introducing normal and weft yarns into a three-dimensional woven fabric according to claim 5, characterized in that, The introduction angle of the normal yarn is 0 to 45°. The introduction angle refers to the angle between the introduced normal yarn and the thickness direction of the fabric.

7. A three-dimensional woven fabric prepared by the method according to any one of claims 5 to 6.

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