1. A method for weaving a variable-diameter three-dimensional woven tubular fabric by using a common weaving machine, which is characterized by comprising the following steps:

(1) and (3) machine installation preparation: designing a card drawing, prefabricating all warps according to the maximum diameter of the three-dimensional woven tubular fabric, wherein the warps comprise base yarns (warps 1) and supplementary yarns (warps 2), the supplementary yarns (warps 2) are positioned on the left side and the right side of the base yarns (warps 1), the number of strands of the supplementary yarns (warps 2) on the left side and the right side is the same, and drafting and reeding operations are carried out after prefabrication;

(2) weaving: simultaneously cutting off a strand of complementary yarn (warp yarn 2) on two sides of the fabric, bending the cut complementary yarn (warp yarn 2), using the bent complementary yarn as weft yarn of the next weaving cycle to be driven into the fabric for consolidation, and repeating the operations until all the complementary yarn (warp yarn 2) are cut off, thereby finishing weaving.

2. The method according to claim 1, wherein in the step (1), the yarn fineness of the fabric is 80-800 tex.

3. The method according to claim 1, wherein in step (1), the fabric has a reed number of 20-60.

4. The method of claim 1, wherein the weave of the fabric is at least one of plain, twill, and satin.

5. The method of claim 1 wherein in step (2) the selected weave pattern has an even number of weave repeat warp yarns.

6. The method according to claim 1, characterized in that the operations are repeated by cutting the complementary yarns (warp yarns 2) on the left and right sides of the fabric and then bending them alternately into weft yarns to beat-up, each complementary yarn (warp yarn 2) beating-up twice as a weft yarn, and cutting one more complementary yarn (warp yarn 2) on each of the left and right sides of the fabric every 4 beating-up times.

Background

The three-dimensional woven tubular fabric is compounded with substrates with different properties to prepare the composite tubular structural member, and has the advantages of good mechanical property and low production cost. However, most of the existing three-dimensional woven tubular structural members are common round tubes, and the requirements of various fields on the variable-diameter tubular structural members cannot be met. The existing preparation technology of the variable-diameter three-dimensional woven tubular fabric comprises two modes of modifying a loom and directly cutting yarns. The modified loom needs to customize a reed and install a matched lifting device, the pipe diameter is changed by changing the warp density, the fabric structure is complete, the mechanical property is good, but the production cost is high, and the production difficulty is high. The method for directly cutting the supplementary yarn is simple and easy to implement, but the edge of the formed fabric is irregular and easy to fall off, stress concentration points are formed at the cutting position of the yarn, and the overall mechanical property is poor.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for weaving a variable-diameter three-dimensional woven tubular fabric by using a common weaving machine. The fabric is composed of a base yarn (warp yarn 1) and a supplementary yarn (warp yarn 2), the diameter of a three-dimensional woven pipe is changed by adopting a flat-pressing-weaving-reduction weaving method and gradually reducing the supplementary yarn (warp yarn 2), the supplementary yarn (warp yarn 2) is sheared and bent into weft yarn, and the weft yarn is driven into the fabric for consolidation. The weaving method solves the problems of irregular edge, easy shedding and poor performance of the variable-diameter three-dimensional woven tubular fabric during the fabric forming due to the fact that the yarn is cut at the edge of the variable-diameter three-dimensional woven tubular fabric through the technical characteristic that the complementary yarn (warp yarn 2) replaces weft yarn, overcomes the defect of poor mechanical property of the edge of the variable-diameter three-dimensional woven tubular fabric, has the advantages of difficult shedding and good integrity, and meets the requirements of the fields of aerospace, fluid transportation and the like on variable-diameter composite material structural members.

In order to achieve the purpose, the invention provides the following technical scheme:

the method for weaving the variable-diameter three-dimensional woven tubular fabric by using a common weaving machine comprises the following steps:

(1) and (3) machine installation preparation: designing a card drawing and a warp direction section drawing of the tubular fabric according to the fabric requirements, calculating the number of warp yarns according to the maximum diameter of the three-dimensional woven tubular fabric, prefabricating all the warp yarns comprising base yarns (warp yarns 1) and supplementary yarns (warp yarns 2), wherein the supplementary yarns (warp yarns 2) are positioned on the left side and the right side of the base yarns (warp yarns 1), the number of strands of the supplementary yarns (warp yarns 2) on the left side and the right side is the same, and after prefabricating, selecting a drafting method and a reed with a proper reed number according to the card drawing to perform drafting and reed penetrating operations;

(2) weaving: simultaneously cutting off a strand of complementary yarn (warp yarn 2) on two sides of the fabric, bending the cut complementary yarn (warp yarn 2), using the bent complementary yarn as weft yarn of the next weaving cycle to be driven into the fabric for consolidation, and repeating the operations until all the complementary yarn (warp yarn 2) are cut off, thereby finishing weaving.

As a preferable technical scheme, in the step (1), the yarn fineness of the fabric is 80-800 tex.

As a preferred technical scheme, in the step (1), the reed number used by the fabric is 20-60.

As a preferable technical scheme, the weave of the fabric is at least one of plain weave, twill weave and satin weave.

As a preferred technical scheme, in the step (2), the number of the selected weave circulation warp yarns of the fabric weave is even.

As a preferable technical scheme, the complementary yarns (warp yarns 2) on the left side and the right side of the fabric are cut off and then are sequentially and alternately bent into weft yarns to beat up, each complementary yarn (warp yarn 2) is beat up twice as a weft yarn, the complementary yarns (warp yarns 2) on the two sides are beat up for 4 times, one complementary yarn (warp yarn 2) is cut off on the left side and the right side of the fabric respectively, and the operation is repeated.

In the method, an upper fabric and a lower fabric are woven simultaneously and are connected through a complementary yarn (warp yarn 2), and two strands of complementary yarn (warp yarn 2) which are cut off simultaneously need to come from the upper fabric and come from the lower fabric. The complementary yarn (warp 2) from the lower fabric is driven into the upper layer, the complementary yarn (warp 2) from the upper fabric is driven into the lower layer, the complementary yarn (warp 2) driven into the lower fabric is driven into the upper layer, and the complementary yarn (warp 2) driven into the upper fabric is driven into the lower layer, namely, each complementary yarn (warp 2) is taken as weft yarn and is driven twice.

The fabric taper of the invention is related to the density of the weft yarns and the number of the supplementary yarns (warp yarns 2) cut off each time, and the taper of the fabric can be increased by increasing the weft density or increasing the number of the supplementary yarns (warp yarns 2) cut off each time.

Compared with the prior art, the invention has the following advantages:

the preparation method of the invention can weave the variable-diameter three-dimensional woven tubular fabric on common looms such as dobby looms, rapier looms and the like without modifying looms. By using the mode of driving the supplementary yarn (warp 2) into the fabric as weft, the integrity of the material is improved, the raw material of the yarn is saved, the production cost is reduced, and the social benefit is better.

Drawings

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

FIG. 1 is a schematic view of a weaving process;

FIG. 2 is a top plan view of the fabric of example 1;

FIG. 3 is a cross-sectional view in the warp direction of the fabric of example 1;

FIG. 4 is a schematic view of the supplemental yarn (warp 2) bending and consolidation of example 1;

fig. 5 is a representation of a fabric article woven in example 1.

Detailed Description

The following description of non-limiting embodiments merely illustrates the basic principles and essential features of the invention, and does not limit the variations of the invention in any way. Variations and modifications of the present invention are within the scope of the invention as claimed. The technical scheme of the invention is further explained by combining the drawings and the specific embodiment.

Example 1

A variable-diameter three-dimensional woven tubular fabric is designed, wherein the diameter of the large end of the fabric is 60mm, the diameter of the small end of the fabric is 40mm, the height of the fabric is 240mm, the taper of the fabric is 1:12, the density of warp yarns is 220/10 cm, the density of weft yarns is 30/10 cm, the taper of the fabric is 1:12, and hemp yarns with the fineness of 400tex are selected as warps and wefts. The weaving method of the fabric comprises the following steps:

(1) preparation for mounting on computer

a. The card drawing of the fabric is designed, and the fabric top drawing is drawn according to the card drawing (shown in figure 2). The tubular fabric is woven on a common loom, an upper layer of fabric and a lower layer of fabric are simultaneously woven and connected by weft yarns, the thickness of the tube wall of the fabric is one layer, the fabric weave is designed to be a double-layer plain weave, and the number of circulating warp yarns of each weave is 4.

b. The fabric is shown in a cross-sectional view in the warp direction (as in FIG. 3), with the black circles representing the weft yarns, weft yarn a and weft yarn b being connected and weft yarn c and weft yarn d being connected, thereby closing the tubular fabric on both sides.

c. Calculating the number of warp yarns: the number of the fabric layers is 2, each layer of 2 strands of warp yarns is calculated to totally need 54 warp yarn circulations according to the size of the large end of the fabric and the density of the warp yarns and the weft yarns, and the total number of the warp yarns is 216; the fabric small end is designed to be 42 warp yarn cycles, i.e., 168 base yarns (warp yarn 1); the calculation results in 24 supplemental yarns (warp yarns 2) on the left and right sides, respectively, for a total of 48 supplemental yarns.

d. All 216 warp yarns are preset in the order of 24 supplemental yarns (warp 2) -168 base yarns (warp 1) -24 supplemental yarns (warp 2) (as shown in figure 1).

e. Drafting: and (4) reeding by adopting a forward drawing method according to the designed drafting diagram to share the total number of the heald frames.

f. Reeding: and reeding is carried out according to a designed reeding diagram, the reed number is 55, and 4 warps are reeded in each reed.

(2) Weaving

a. According to the weave diagram, the yarns penetrating the first two heddle frames weave the upper fabric layer and the yarns penetrating the third four heddle frames weave the lower fabric layer. A complementary yarn a1 from the first heddle is cut on the left side of the fabric and a complementary yarn B4 from the fourth heddle is cut on the right side and a length greater than twice the fabric width is reserved. The complementary yarn B4 from the lower fabric is bent and driven into the upper fabric, and the complementary yarn a1 from the upper fabric is driven into the lower fabric (as shown in fig. 4); then A1 is punched into the upper layer fabric, B4 is punched into the lower layer fabric, and the two sides of the fabric are sealed.

b. Cutting off a complementary yarn a2 from the second leaf heddle on the left side and a complementary yarn B3 from the fourth leaf heddle on the right side; the complementary yarn B3 from the lower fabric is bent and driven into the upper fabric, and the complementary yarn A2 from the upper fabric is driven into the lower fabric; then A2 is punched into the upper layer fabric, and B3 is punched into the lower layer fabric.

c. Cutting off a complementary yarn A3 from a third page heddle on the left side, cutting off a complementary yarn B2 from a fourth page heddle on the right side, bending and driving the complementary yarn B2 from the upper layer fabric into the lower layer fabric, and driving the complementary yarn A3 from the lower layer fabric into the upper layer fabric; then A3 is punched into the upper layer fabric, and B2 is punched into the lower layer fabric.

d. Cutting off a complementary yarn A4 from a third page heddle on the left side, cutting off a complementary yarn B1 from a fourth page heddle on the right side, bending and driving the complementary yarn B1 from the upper layer fabric into the lower layer fabric, and driving the complementary yarn A4 from the lower layer fabric into the upper layer fabric; then A4 is punched into the upper layer fabric, and B1 is punched into the lower layer fabric.

e. And repeating the operations a-d until 48 supplementary yarns (warp yarns 2) are completely cut off and the weaving is finished.

f. After the machine is off, the fabric is spread by using a die, and the complementary yarn (warp yarn 2) is trimmed to obtain a variable-diameter three-dimensional woven tubular fabric (as shown in figure 5), wherein the diameter of the large end of the fabric is 60mm, the diameter of the small end of the fabric is 40mm, the height of the fabric is 240mm, and the taper of the fabric is 1: 12.

In this example, the number of complementary yarns (warp yarns 2) is one for each cutting, for the purpose of: the fineness of the warp and weft yarns is consistent, and the fabric structure is uniform.

In this example, the left and right complementary yarns (warp 2) cut at each time are uniformly fed from the upper fabric and one from the lower fabric, and the complementary yarn (warp 2) from the upper fabric is fed into the lower fabric and the complementary yarn (warp 2) from the lower fabric is fed into the upper fabric during weaving, thereby connecting the two fabrics.

In the weaving process, because double-layer fabrics need to be woven simultaneously, the warp density is large, the problem of unclear opening is easy to occur, and the method for improving the back beam can be adopted for improvement.

Example 2

A variable-diameter three-dimensional woven tubular fabric is designed, wherein the diameter of the large end of the fabric is 600mm, the diameter of the small end of the fabric is 400mm, the height of the fabric is 2400mm, the taper of the fabric is 1:12, the density of warp yarns is 220/10 cm, the density of weft yarns is 30/10 cm, the taper of the fabric is 1:12, and hemp yarns with the fineness of 400tex are selected as warps and wefts. The weaving method of the fabric comprises the following steps:

the fabric preparation steps and weaving method are the same as in example 1, except that:

the overall size of the fabric is enlarged by 10 times, and according to the size of the big end of the fabric and the density of the warp and weft yarns, 540 warp yarn circulations are calculated, the total number of warp yarns is 2160, wherein 1680 of basic yarns (warp yarns 1) and 480 of supplementary yarns (warp yarns 2). The preset sequence of the warp yarns is as follows: 240 supplemental yarns (warp 2) -base yarns (warp 1) 1680-240 supplemental yarns (warp 2).

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.