Device and method for preparing spiral auxetic fiber with stable initial structure

Abstract

The invention discloses a preparation device and method for spiral auxetic fibers with a stable initial structure, and belongs to the technical field of building fiber preparation. Comprising a core fiber feeding control mechanism, a wrapping fiber feeding control mechanism, a spiral auxetic fiber forming and winding mechanism and a fiber cutting mechanism which are sequentially arranged, and a glue dripping mechanism is arranged above one end of the fiber cutting mechanism; the core fiber feeding control mechanism comprises a core fiber pipe, a fiber feeding roller, a tension disc and a fiber guiding pipe, the core fiber pipe is placed on the fiber feeding roller, the fiber guiding pipe is arranged above the tension disc, the end of core fiber on the core fiber pipe is wound on the tension disc, and the tension disc is arranged above the core fiber pipe. The wrapping fiber is vertically fed into the wrapping fiber feeding control mechanism from the bottom of the fiber guide pipe; according to the technical scheme, the spiral auxetic fiber which is uniform and stable in initial structure and obvious in negative Poisson's ratio effect is prepared in a physical consolidation and chemical gluing mode, and then the spiral auxetic fiber is cut into the short spiral auxetic fiber sections, so that the short spiral auxetic fiber sections can be conveniently applied to concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of building fibers, and particularly relates to a preparation device and method for a helical tensile-expansion fiber with a stable initial structure. Background Art

[0002] The application of fibers in the field of civil engineering mainly focuses on concrete reinforcement. Generally, fibers play a role in the form of being incorporated into concrete. When a concrete structure is subjected to an external load, the fibers connect the two sides of the crack through a bridging effect, effectively absorbing and dispersing stress, thereby reducing the width and number of cracks. In addition, the bonding force between the fibers and the matrix can disperse local high stress to a larger area, reducing the stress concentration phenomenon, and thus enhancing the overall strength and toughness of the concrete. At present, fiber-reinforced concrete mainly adopts the method of incorporating a single fiber or mixing multiple fibers. However, the incorporation of a single fiber has the disadvantages of a single and limited reinforcement effect, while the mixing of multiple fibers is difficult to fully exert the synergistic reinforcement effect of the hybrid fibers. The helical tensile-expansion fiber is a multi-component fiber, and its unique negative Poisson's ratio effect enables it to play a role in concrete.

[0003] Patent CN108558312A involves wrapping a layer of epoxy resin on the outer layer of the synthesized upper helical tensile-expansion fiber for curing, cutting it into fiber segments with a length of 2.5 ± 0.5 mm after air drying, and adding it to the concrete. Although the performance can be improved through resin curing to make its structure stable, the cured fiber is relatively hard, affecting the effective exertion of its negative Poisson's ratio effect and limiting its application in concrete.

[0004] Therefore, it is necessary to innovate the existing preparation method of short-cut helical tensile-expansion fibers to solve problems such as the non-obvious negative Poisson's ratio effect and unstable initial structure after cutting into short fibers. There is an urgent need for a simple and universal preparation method to produce helical tensile-expansion fibers with an obvious negative Poisson's ratio effect and a stable initial structure to promote their application in the field of concrete. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a preparation device and method for a helical tensile-expansion fiber with a stable initial structure. By means of physical consolidation and chemical adhesion, the wrapped fiber and the core fiber are formed into a helical tensile-expansion fiber with a uniform and stable initial structure and an obvious negative Poisson's ratio effect, and then it is cut into short helical tensile-expansion fibers by a cutting method, which is convenient for its application in concrete.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A preparation device for a spiral expansion fiber with stable initial structure, comprising a core fiber feeding control mechanism, a wrapping fiber feeding control mechanism, a spiral expansion fiber forming and winding mechanism, and a fiber cutting mechanism arranged in sequence. Above one end of the fiber cutting mechanism, there is a glue dripping mechanism; The core fiber feeding control mechanism includes a core fiber tube, a fiber feeding roller, a tension disc, and a fiber guiding tube. The core fiber tube is placed on the fiber feeding roller. The fiber guiding tube is arranged above the tension disc. The end of the core fiber on the core fiber tube is wound around the tension disc and vertically fed into the wrapping fiber feeding control mechanism from the bottom of the fiber guiding tube; The wrapping fiber feeding control mechanism includes a base and a number of wrapping fiber tubes; the spiral expansion fiber forming and winding mechanism includes a converging hole, a first fiber guiding roller, and a second fiber guiding roller; the base is rotatably arranged. The fiber guiding tube is arranged in the middle of the base. A number of the wrapping fiber tubes are circumferentially and evenly arranged on the base. The converging hole is arranged above the wrapping fiber tubes. The wrapping fibers on a number of the wrapping fiber tubes are spirally wrapped around the surface of the core fiber at the converging hole to form a spiral expansion fiber. The end of the spiral expansion fiber is sequentially wound around the first fiber guiding roller and the second fiber guiding roller. The second fiber guiding roller drives the end of the spiral expansion fiber to move towards the position of the fiber cutting and limiting mechanism; The fiber cutting mechanism includes a guide rail strip, a moving knife, and a fixed knife. The guide rail strip is used for conveying the spiral expansion fiber. The moving knife and the fixed knife are arranged behind one end of the guide rail strip away from the spiral expansion fiber for cutting the spiral expansion fiber; The glue dripping mechanism is arranged above one end of the guide rail strip close to the spiral expansion fiber and includes a glue dripping needle tube for dripping the internal glue at a specified position of the spiral expansion fiber.

[0007] Furthermore, the fiber cutting mechanism further includes a driving device. The moving knife is connected to the driving device. There is a protective cover outside the fiber cutting mechanism. There is a discharge port at the rear end of the protective cover. Below the discharge port, there is a packing box.

[0008] Furthermore, the number of the first fiber guiding rollers is two. The two first fiber guiding rollers are arranged at the same height and the rotation directions of the two first fiber guiding rollers are opposite.

[0009] Furthermore, the number of the second fiber guiding rollers is two. The two second fiber guiding rollers are arranged vertically opposite to each other and the rotation directions of the two second fiber guiding rollers are opposite.

[0010] Furthermore, the core fiber on the core fiber tube is made of one of polypropylene, polyvinyl alcohol and glass fiber filaments, the number of the wrapping fiber tubes is 2-3, and the material of the wrapping fibers on the wrapping fiber tubes is metal or flexible fiber.

[0011] Furthermore, a glue coating mechanism is provided between the glue dripping mechanism and the fiber cutting mechanism, and the glue coating mechanism includes an arc-shaped gear ring, and a plurality of cylindrical gears evenly distributed around the circumference are provided on the outer side of the arc-shaped gear ring, and the cylindrical gears are meshed with the arc-shaped gear ring, and an arc-shaped plate is provided at one end of the arc-shaped gear ring, and a plurality of driving motors are provided on the arc-shaped plate, and the driving motor is connected to one end of the cylindrical gear, and an arc-shaped airbag is provided on the inner side surface of the arc-shaped gear ring, one side of the arc-shaped airbag is fixed on the arc-shaped gear ring, and a sponge layer is bonded to the other side of the arc-shaped gear ring, and an air pump is provided on the arc-shaped plate, and the output end of the air pump is connected to the inside of the arc-shaped airbag through an air pipe.

[0012] Furthermore, a stopper is provided on the other end of some of the columnar gears, and the stopper limits the translation of the arc-shaped gear ring.

[0013] A method for preparing a spiral axial expansion fiber with an initial stable structure, when the wrapped fiber is made of metal, comprises the following preparation steps: Step 1: Place the core fiber tube on the fiber feeding roller. The core fiber on the core fiber tube passes through the tension disk under the rotation of the fiber feeding roller and is vertically fed from the bottom center of the fiber guide tube; then unwind the wrapping fiber from the wrapping fiber tube, pass through the convergence hole and converge with the core fiber to form a spiral tensile fiber, which is then wound on the first fiber guide roller, passed through the middle of the second fiber guide roller and placed on the guide rail. Finally, the formed spiral tensile fiber is transported and passed over the fixed knife; Step 2: By operating the control system, the rotation speed of the first fiber guide roller and the second fiber guide roller is 1-2r / min, each rotation lasts for three seconds and stops for one second, and the base continues to rotate at a rotation speed of 10-20r / min, so as to obtain the spiral expansion fiber; Step 3: Align a section of the spiral expansion fiber that has been wound on the guide rail with the fixed knife after being wrapped with a metal wire hoop, start the moving knife drive device, adjust its speed to 1-2r / min, so that its speed is the same as that of the second fiber guide roller, and the moving knife cuts off the tight section of the spiral expansion fiber, and the cut short spiral expansion fiber is discharged from the end of the guide rail.

[0014] Furthermore, when the wrapping fiber is a flexible fiber, the method comprises the following preparation steps: Step 1: Place the core fiber tube on the fiber feeding roller. The core fibers on the core fiber tube are vertically fed from the center position at the bottom of the fiber guiding tube through the tension disk under the rotation of the fiber feeding roller. Then, unwind the wrapping fibers from the wrapping fiber tube. The wrapping fibers unwound from the wrapping fiber tube pass through the converging holes and converge with the core fibers into a single helical expansion fiber, which is then wound around the first fiber guiding roller, passes through the middle of the second fiber guiding roller, and is placed on the guide rail strip. Finally, the helical expansion fiber is transported through above the fixed knife. Step 2: Through the operation control system, set the rotation speeds of the first fiber guiding roller and the second fiber guiding roller to 1 - 3 r / min, and the rotation speed of the base to 10 - 20 r / min, and keep them rotating continuously throughout the process to obtain the helical expansion fiber. Step 3: Turn on the glue dripping device. Place the helical expansion fiber on the guide rail strip under the needle of the glue dripping device. Control the glue dripping device to make the needle drip a drop of glue every 3 - 5 seconds, so that it adheres to the surface of the helical expansion fiber, and the helical expansion fiber with glue dripping and forming can be obtained. Step 4: Align a section of the glued part of the helical expansion fiber that has been wound and formed with glue on the guide rail strip with the fixed knife. Start the moving knife driving device, adjust its rotation speed to 1 - 3 r / min, so that its rotation speed is the same as that of the second fiber guiding roller. The moving knife cuts off the glued part of the helical expansion fiber, and the cut short helical expansion fiber is discharged from the end of the guide rail strip.

[0015] Further, in Step 3, the following steps are also included: When the glue dripping device drips the glue into the helical expansion fiber from the notch of the arc-shaped gear ring, at this time, the air pump inflates the arc-shaped airbag, so that the sponge layer contacts the surface of the helical expansion fiber. Then, the driving motor drives the gear ring to rotate reciprocally, and evenly coats the glue on the surface of the helical expansion fiber. After the coating is completed, the driving motor drives the arc-shaped gear ring to return to the initial position, and then the arc-shaped airbag deflates to separate the sponge layer from the surface of the helical expansion fiber.

[0016] The beneficial effects of the present invention are as follows: (1) The helical expansion fiber line adopts a brand-new winding method, effectively improving the slippage phenomenon caused by different types of wrapping fibers, and also effectively preventing the residual torque of multi-strand fibers from untwisting, thereby improving its wrapping effect and fiber strength. (2) The fiber spinning method of the preparation device is simple, easy to operate, and has a low cost. It is suitable for continuous production and popularization. At the same time, the preparation device can also select different consolidation methods according to the materials of different wrapping fibers to ensure the preparation effect of the segments of the helical expansion fiber.

[0017] (3) The short-cut expansion composite fiber line described in the present invention has good forming, stable structure, unique performance, and obvious expansion effect, and can be widely used in concrete.

[0018] Other advantages, objects, and features of the present invention will be set forth in the following description, and to some extent will be obvious to those skilled in the art, or can be learned by those skilled in the art from the practice of the present invention. The objects and other advantages of the present invention can be achieved and obtained by the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the objects, technical solutions, and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration: Figure 1 It is a schematic plan view of a preparation device for a helically expandable fiber with stable initial structure of the present invention; Figure 2 It is a schematic top view of a helically expandable fiber forming mechanism of the present invention; Figure 3 It is a schematic view of a glue dripping device of the present invention; Figure 4 It is a schematic view of a moving knife driving device of the present invention; Figure 5 It is a schematic diagram of the cutting of the tight wrapping section of the helically expandable fiber of the present invention (left figure) and a schematic diagram of the cut short fiber (right figure); Figure 6 It is a schematic diagram of the cutting at the glue dripping position of the helically expandable fiber of the present invention (left figure) and a schematic diagram of the cut short fiber (right figure); Figure 7 It is a three-dimensional schematic view of a glue coating mechanism of the present invention from one perspective; Figure 8 It is a three-dimensional schematic view of the glue coating mechanism of the present invention from another perspective; Figure 9 It is a schematic cross-sectional view of the front view of the glue coating mechanism of the present invention.

[0020] The reference signs in the drawings are as follows: 1 - fiber feeding roller, 2 - core fiber tube, 3 - core fiber, 4 - tension disk, 5 - fiber guiding tube, 6 - base, 7 - wrapping fiber tube, 8 - wrapping fiber, 9 - converging hole, 10 - helically expandable fiber, 11 - first fiber guiding roller, 12 - second fiber guiding roller, 13 - glue dripping needle, 14 - glue, 15 - glue dripping syringe, 16 - guide rail bar, 17 - fixed knife, 18 - moving knife, 19 - protective cover, 20 - discharge port, 21 - storage box; 22 - bracket, 23 - compressed gas, 24 - control device, 25 - driving gear, 26 - arc plate, 27 - arc gear ring, 28 - columnar gear, 29 - driving motor, 30 - stop block, 31 - arc-shaped airbag, 32 - sponge layer, 33 - air pump, 34 - air pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] As Figures 1 to 6As shown in the figure, a preparation device for a spiral expansion fiber with stable initial structure according to the present invention includes a fiber component feeding control structure, a spiral expansion fiber forming and winding mechanism, a glue dropping mechanism, and a fiber cutting mechanism. The fiber component feeding control structure includes a core fiber feeding control mechanism and a wrapping fiber feeding control mechanism; the core fiber feeding control mechanism includes a core fiber tube 2, a fiber feeding roller 1, a fixed frame, and a fiber guiding tube 5. The core fiber tube 2 is placed on the fiber feeding roller 1. One side of the fixed frame close to the core fiber tube 2 is provided with a fiber guiding hole, and the other side is provided with a tension disk 4. The fiber guiding tube 5 is arranged above the tension disk 4. The core fiber 3 on the core fiber tube 2 can be vertically fed from the center position at the bottom of the fiber guiding tube 5 through the fiber guiding hole and the tension disk 4 on the fixed frame in sequence under the rotation of the fiber feeding roller 1; the wrapping fiber feeding control mechanism includes a base 6 and a wrapping fiber 8 arranged on the base 6. The spiral expansion fiber forming and winding mechanism includes a converging device (converging plate) with a converging hole 9, a first fiber guiding roller 11, and a second fiber guiding roller 12. There is at least one wrapping fiber 8, which is arranged around the fiber guiding tube 5. The converging hole 9 is arranged above the fiber guiding tube 5 and the wrapping fiber 8. The wrapping fiber 8 unwound from the wrapping fiber 8 can be spirally wrapped around the core fiber 3 at the converging hole 9 to form a spiral expansion fiber 10, and this spiral expansion fiber 10 can pass through the first fiber guiding roller 11 and the second fiber guiding roller 12 in sequence; the glue dropping mechanism includes a control device 24, compressed gas 23, a glue dropping syringe 15, glue 14, and a glue dropping needle head 13; the fiber cutting mechanism includes a guide rail strip 16, a moving knife 18, and a fixed knife 17. The moving knife 18 is installed on the moving knife seat, the moving knife seat is connected to the driving device, the fixed knife 17 is installed on the fixed knife seat, the fixed knife seat is fixed on the bracket 22, and a protective cover 19 is arranged outside the fiber cutting mechanism. A discharge port 20 is arranged at the rear end of the protective cover 19, and a packing box 21 is placed below the discharge port 20.

[0022] Preferably, the core fiber 3 is one of polypropylene, polyvinyl alcohol, and glass fiber filaments; the number of the wrapping fibers 8 is 2 - 3, which is one of metal and flexible fiber, and both single filaments and multifilaments are acceptable, and the same or different filaments are selected according to the use.

[0023] Preferably, the diameter ratio of the core fiber 3 to the wrapping fiber 8 is greater than 1, and the tensile modulus ratio of the wrapping fiber 8 to the core fiber 3 is greater than 10.

[0024] Preferably, when the wrapping fiber 8 is metal, the physical consolidation method is selected for wrapping, and when the wrapping fiber 8 is flexible fiber, the chemical gluing method is selected for wrapping.

[0025] Preferably, the feeding state, stable feeding speed, and uniform fiber line tension of the core fiber 3 are controlled by the fiber feeding roller 1 and the tension disk 4.

[0026] Preferably, the wrapping fibers 8 on each wrapping fiber 8 are fed simultaneously and at the same speed.

[0027] Preferably, the driving device adopts an electric component, and a driving gear 25 is provided on the electric component. The rotation of the driving gear 25 drives the moving knife 18 to reciprocate up and down. The specific driving structure is the prior art. Of course, it is also possible to use a telescopic rod to drive, and no more details will be elaborated here.

[0028] Preferably, the control system adopts a PLC. The control system is used to operate and control the working procedure of the machine.

[0029] Preferably, there are two first fiber guide rollers 11 in total, which are arranged on a horizontal plane and rotate in opposite directions.

[0030] Preferably, there are two second fiber guide rollers 12 in total, which are arranged on a vertical plane and rotate in opposite directions.

[0031] Preferably, a guide rail strip 16 arranged in the horizontal direction is further provided on the bracket 22, and the guide rail strip 16 is respectively matched with the second fiber guide roller 12, the fixed knife 17 and the moving knife 18.

[0032] As Figures 7 - 9 shown, preferably, a gluing mechanism is provided between the glue dropping mechanism and the fiber cutting mechanism. The gluing mechanism includes an arc-shaped gear ring 27. A number of columnar gears 28 are circumferentially and evenly arranged on the outer side of the arc-shaped gear ring 27. The columnar gears 28 are meshed with the arc-shaped gear ring 27. One end of the arc-shaped gear ring 27 is provided with an arc-shaped plate 26. A number of driving motors 29 are provided on the arc-shaped plate 26. The driving motors 29 are connected to one end of the columnar gears 28. An arc-shaped air bag 31 is provided on the inner side surface of the arc-shaped gear ring 27. One side of the arc-shaped air bag 31 is fixed to the arc-shaped gear ring 27. A sponge layer 32 is adhesively provided on the other side of the arc-shaped gear ring 27. An air pump 33 is provided on the arc-shaped plate 26. The output end of the air pump 33 is communicated with the inside of the arc-shaped air bag 31 through an air pipe 34.

[0033] The working principle of the above technical solution is as follows: When the glue 14 is dropped into the arc-shaped gear ring 27, it first contacts the upper surface of the spiral expansion fiber 10, and then falls onto the sponge layer 32. At this time, only by inflating the airbag through the air pump 33 can the sponge layer 32 contact the spiral expansion fiber 10. Then, the driving motor 29 rotates the columnar gear 28, which in turn drives the sponge layer 32 to rotate. As a result, the glue 14 on the sponge layer 32 is coated on the spiral expansion fiber 10, and then the whole is reset. The advantage of this setting method is that it can evenly coat the glue 14 on the parts of the spiral expansion fiber 10 that need to be coated with glue, while ensuring the coating effect of the lower part of the spiral expansion fiber 10, thereby ensuring the later consolidation effect. At the same time, the advantage of the arc-shaped airbag 31 is that it will not affect the movement of the spiral expansion fiber 10 when the glue 14 is not coated. At the same time, the advantage of the sponge layer 32 is that it can absorb the residual glue 14, which is convenient for subsequent coating use. At the same time, the sponge layer 32 can be replaced at any time to ensure the coating effect.

[0034] Preferably, a stopper 30 is provided at the other end of a part of the columnar gear 28. The stopper 30 limits the translation of the arc-shaped gear ring 27 to prevent the arc-shaped gear ring 27 from coming off.

[0035] Preferably, the air pump 33 fills the arc-shaped airbag 31 with hot air, that is, the hot air heats the arc-shaped airbag 31, and then transfers the heat to the sponge layer 32, thereby preventing the residual glue 14 on the sponge layer 32 from curing and affecting the coating effect of the spiral expansion fiber 10.

[0036] A preparation method of an initially stable structure spiral expansion fiber. When the wrapping fiber is made of metal, it includes the following preparation steps: Step 1: Place the core fiber tube 2 on the fiber feeding roller 1. The core fiber 3 on the core fiber tube 2 is vertically fed into the bottom center position of the fiber guiding tube 5 through the pulley and the tension disc 4 in turn under the rotation of the fiber feeding roller 1. Then, the wrapping fiber 8 is unwound from the wrapping fiber tube 7. The wrapping fiber 8 unwound from the wrapping fiber tube 7 passes through the converging hole 9 of the converging device and converges with the core fiber 3 into a spiral expansion fiber 10, which is then wound around the first fiber guiding roller 11, passes through the middle of the second fiber guiding roller 12, and is placed on the guide rail 16. Finally, the formed spiral expansion fiber 10 is transported through the fixed knife 17.

[0037] Step 2: Through the operation control system, the rotation speeds of the first fiber guiding roller 11 and the second fiber guiding roller 12 are 1-2 r / min. For every three seconds of rotation, it stops for one second. The rotation speed of the base 6 is 10-20 r / min and does not stop during the process, and the spiral expansion fiber can be obtained.

[0038] Step 3: Align a section of the helically tension-expanded fiber 10 that has been wound and formed on the guide rail 16 and passes through the part tightly wound with wire to the fixed knife 17. Start the moving knife drive device and adjust its rotational speed to 1 - 2 r / min, making its rotational speed the same as that of the second fiber guiding roller 12. The moving knife 18 cuts off the tightly wound section of the helically tension-expanded fiber, and the cut short helically tension-expanded fiber falls into the packing box 21 from the discharge port 20.

[0039] Example 1: Preparation of polypropylene / steel wire helically tension-expanded fiber with a diameter ratio of 3:1 and a wrapping angle of 15°; Using the above-mentioned preparation device, select 1 polypropylene fiber with a diameter of 0.9 mm and 1 steel wire with a diameter of 0.3 mm as the core fiber and the wrapping fiber respectively. The specific steps include: Step 1: Place the polypropylene fiber tube on the fiber feeding roller 1. The polypropylene fiber on the polypropylene fiber tube sequentially passes through the pulley and the tension disc 4 under the rotation of the fiber feeding roller 1 and is vertically fed into the bottom center position of the fiber guiding tube 5. Then unwind the single-strand steel wire from the steel wire tube. The steel wire unwound from the steel wire tube passes through the converging hole 9 of the converging device and converges with the polypropylene fiber into a helically tension-expanded fiber 10, which is then wound on the first fiber guiding roller 11, passes through the middle of the second fiber guiding roller 12, and is placed on the guide rail 16. Finally, the formed helically tension-expanded fiber is transported through above the fixed knife 17.

[0040] Step 2: Through the operation control system, make the rotational speeds of the first fiber guiding roller 11 and the second fiber guiding roller 12 be 2 r / min, stop for one second, and the rotational speed of the base 6 is 15 r / min without stopping, then the helically tension-expanded fiber 10 can be obtained and the distance between the spaced tightly wound sections is 50 mm.

[0041] Step 3: Align a section of the helically tension-expanded fiber 10 that has been wound and formed on the guide rail 16 and passes through the part tightly wound with steel wire to the fixed knife 17. Start the moving knife drive device and adjust its rotational speed to 2 r / min, making its rotational speed the same as that of the second fiber guiding roller 12. The moving knife 18 cuts off the tightly wound section of the helically tension-expanded fiber, and the cut helically tension-expanded fiber 18 falls into the packing box 21 from the discharge port 20 and the length of each fiber is 50 mm.

[0042] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the short-cut helical auxetic fibers to observe the change in their diameters, and thus calculate the Poisson's ratio. First, a universal tensile machine was used to stretch 50-mm short fibers. During the stretching process, the change process of the fibers was recorded by a camera. The stretching ended when the helical auxetic fibers broke. Subsequently, a computer software was used to analyze the experimental results and calculate the Poisson's ratio. The starting strain of the fibers with negative Poisson's ratio produced by the method of the present invention was optimized from 10% to 2%, and the maximum negative Poisson's ratio was optimized to -3.61. The negative Poisson's ratio effect of the fibers was obvious, and they had a greater expansion effect. The short-cut fibers had high strength and stability, meeting the requirements for use in concrete.

[0043] Example 2: Preparation of polypropylene / twin-strand steel wire helical auxetic fibers with a diameter ratio of 3:1 and a wrapping angle of 15°; Using the preparation device of Example 1, 1 polypropylene filament with a diameter of 0.9 mm and 2 steel wires with a diameter of 0.3 mm were respectively selected as the core fiber and the wrapping fiber. The specific steps include: Step 1: Place the polypropylene fiber tube on the fiber feeding roller 1. The polypropylene fibers on the polypropylene fiber tube pass through the pulley and the tension disk 4 in turn under the rotation of the fiber feeding roller 1 and are vertically fed into the bottom center position of the fiber guiding tube 5. Then, the twin-strand steel wire is unwound from the steel wire tube. The twin-strand steel wire unwound from the steel wire tube passes through the converging hole 9 of the converging device and converges with the polypropylene fiber into a helical auxetic fiber 10, which is then wound around the first fiber guiding roller 11, passes through the middle of the second fiber guiding roller 12, and is placed on the guide rail bar 16. Finally, the formed helical auxetic fiber is transported through the fixed knife 17.

[0044] Step 2: Through the operation control system, the rotation speeds of the first fiber guiding roller 11 and the second fiber guiding roller 12 are set to 2 r / min, stopping for 1 second every 3 seconds of rotation, and the rotation speed of the base 6 is 15 r / min without stopping during the process. Then, helical auxetic fibers can be obtained with the distance between the tight wrapping sections being 50 mm.

[0045] Step 3: Align a section of the helical auxetic fiber already wound and formed on the guide rail bar 16 that has been tightly wrapped with a metal wire with the fixed knife 17. Start the moving knife driving device, adjust its rotation speed to 2 r / min, making its rotation speed the same as that of the second fiber guiding roller 12. The moving knife 18 cuts off the tight wrapping section of the helical auxetic fiber. The cut helical auxetic fibers fall into the packing box 21 from the discharge port 20, and the length of each fiber is 50 mm.

[0046] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the short-cut helical auxetic fibers to observe the change in their diameter, and thus calculate the Poisson's ratio. First, a universal tensile machine was used to stretch 50-mm short fibers. During the stretching process, the change process of the fibers was recorded by a camera. The stretching ended when the helical auxetic fibers broke. Subsequently, computer software was used to analyze the experimental results and calculate the Poisson's ratio. The initial strain of the fibers with negative Poisson's ratio optimized by the method of the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -11.59. The negative Poisson's ratio effect of the fibers was obvious, and they had a greater expansion effect. The short-cut fibers had high strength and stability, meeting the requirements for use in concrete.

[0047] Example 3: Preparation of polypropylene / three-strand steel wire helical auxetic fibers with a diameter ratio of 3:1 and a wrapping angle of 15°; Using the preparation device of Example 1, one polypropylene filament with a diameter of 0.9 mm and three steel wires with a diameter of 0.3 mm were respectively selected as the core fiber and the wrapping fiber. The specific steps are as follows: Step 1: Place the polypropylene fiber tube on the fiber-feeding roller 1. The polypropylene fibers on the polypropylene fiber tube pass through the pulley and the tension disk 4 in turn under the rotation of the fiber-feeding roller 1 and are vertically fed into the bottom center position of the fiber-guiding tube 5. Then, the three-strand steel wire is unwound from the steel wire tube. The three-strand steel wire unwound from the steel wire tube passes through the converging hole 9 of the converging device and converges with the polypropylene fiber into a helical auxetic fiber 10, which is then wound around the first fiber-guiding roller 11, passes through the middle of the second fiber-guiding roller 12, and is placed on the guide rail strip 16. Finally, the formed helical auxetic fiber is transported through the fixed knife 17.

[0048] Step 2: Through the operation control system, make the rotational speeds of the first fiber-guiding roller 11 and the second fiber-guiding roller 12 be 2 r / min for three seconds and stop for one second, and the rotational speed of the base 6 is 15 r / min without stopping during the process, then helical auxetic fibers can be obtained and the distance between the spaced tight-binding segments is 50 mm.

[0049] Step 3: Align a section of the helical auxetic fiber already wound and formed on the guide rail strip 16 that has been tightly wound with a metal wire with the fixed knife 17. Start the moving knife driving device and adjust its rotational speed to 2 r / min, making its rotational speed the same as that of the second fiber-guiding roller 12. The moving knife 18 cuts off the tight-binding segment of the helical auxetic fiber. The cut helical auxetic fibers fall into the packing box 21 from the discharge port 20, and the length of each fiber is 50 mm.

[0050] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the short-cut helical auxetic fibers to observe the change in their diameter, and thus calculate the Poisson's ratio. First, a universal tensile machine was used to stretch 50-mm short fibers. During the stretching process, the change process of the fibers was recorded by a camera. The stretching ended when the helical auxetic fibers broke. Subsequently, computer software was used to analyze the experimental results and calculate the Poisson's ratio. The initial strain of the fiber line with a negative Poisson's ratio produced by the method optimized by the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -8.65. The negative Poisson's ratio effect of the fibers was obvious, and it had a greater expansion effect. The short-cut fibers had high strength and stability, meeting the requirements for application in concrete.

[0051] Example 4 Preparation of polypropylene / twin-strand steel wire helical auxetic fiber with a diameter ratio of 3:1 and a wrapping angle of 10°; Using the preparation device of Example 1, 1 polyvinyl alcohol filament with a diameter of 0.9 mm and 2 steel wires with a diameter of 0.3 mm were respectively selected as the core fiber and the wrapping fiber. The specific steps include: Step 1: Place the polypropylene fiber tube on the fiber-feeding roller 1. The polypropylene fibers on the polypropylene fiber tube sequentially pass through the pulley and the tension disk 4 under the rotation of the fiber-feeding roller 1 and are vertically fed into the bottom center position of the fiber-guiding tube 5. Then, the twin-strand steel wire is unwound from the steel wire tube. The twin-strand steel wire unwound from the steel wire tube passes through the converging hole 9 of the converging device and converges with the polypropylene fiber into a helical auxetic fiber 10, which is then wound around the first fiber-guiding roller 11, passes through the middle of the second fiber-guiding roller 12, and is placed on the guide rail strip 16. Finally, the formed helical auxetic fiber is transported through the fixed knife 17.

[0052] Step 2: Through the operation control system, the rotational speeds of the first fiber-guiding roller 11 and the second fiber-guiding roller 12 are set to 2 r / min, stopping for 1 second every 3 seconds of rotation, and the rotational speed of the base 6 is 10 r / min and does not stop during the process. In this way, helical auxetic fibers can be obtained with the distance between the tight-binding segments being 50 mm.

[0053] Step 3: Align a section of the helical auxetic fiber 10 already wound and formed on the guide rail strip 16 that has passed through the steel wire tight-binding winding part with the fixed knife 17. Start the moving knife driving device, adjust its rotational speed to 2 r / min, making its rotational speed the same as that of the second fiber-guiding roller 12. The moving knife 18 cuts off the tight-binding segment of the helical auxetic fiber, and the cut helical auxetic fibers fall into the packing box 21 from the discharge port 20, with each fiber having a length of 50 mm.

[0054] In order to verify the innovative contribution of the present invention, a tensile test was conducted on the short-cut spiral tensile fibers to observe the change in their diameter, thereby calculating the Poisson's ratio. First, a universal tensile machine was used to stretch the 50mm short fibers. During the stretching process, the change process of the fibers was recorded by a camera. The stretching was completed until the spiral tensile fibers broke. Then, the experimental results were analyzed using computer software to calculate the Poisson's ratio. The fibers optimized by the method of the present invention produced a negative Poisson's ratio with an initial strain of 21%, and the maximum negative Poisson's ratio was optimized to -7.58. The negative Poisson's ratio effect of the fibers was obvious, and it had a greater expansion effect; the short-cut fibers had high strength and stability, meeting the requirements for application in concrete.

[0055] Example 5: Preparation of polypropylene / double-strand steel wire spiral axial expansion fiber with a diameter ratio of 3:1 and a wrapping angle of 20°; The preparation device of Example 1 is used, and one polypropylene filament with a diameter of 0.9 mm and two steel wires with a diameter of 0.3 mm are selected as the core fiber and the wrapping fiber respectively. The specific steps include: Step 1: Place a polypropylene fiber tube on a fiber feeding roller 1. The polypropylene fibers on the polypropylene fiber tube are vertically fed from the bottom center of the fiber guide tube 5 through the pulley and the tension disk 4 in sequence under the rotation of the fiber feeding roller 1; then unwind the double-strand steel wire from the steel wire tube, and the double-strand steel wire unwound from the steel wire tube passes through the convergence hole 9 of the convergence device and converges with the polypropylene fibers into a spiral expansion fiber 10, which is then wound on the first fiber guide roller 11, and then passes through the middle of the second fiber guide roller 12 and is placed on the guide rail 16. Finally, the formed spiral expansion fiber is transported and passed over the fixed knife 17.

[0056] Step 2: By operating the control system, the rotation speed of the first fiber guide roller 11 and the second fiber guide roller 12 is 1r / min, each rotation for three seconds and stop for one second, the rotation speed of the base 6 is 15r / min and does not stop during the process, and the spiral expansion fiber 10 can be obtained with a spacing of 50mm between the tightening sections.

[0057] Step 3: Align a certain section of the spiral expansion fiber that has been wound on the guide rail 16 and has been wound with a steel wire hoop with the fixed knife 17, start the movable knife driving device, adjust its rotation speed to 1r / min, so that its rotation speed is the same as that of the second fiber guide roller 12, and the movable knife 18 cuts off the spiral expansion fiber hoop section. The cut spiral expansion fibers fall into the packaging box 21 from the discharge port 20 and each fiber has a length of 50mm.

[0058] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the short-cut helical auxetic fibers to observe the change in their diameters, and thus calculate the Poisson's ratio. First, a universal tensile machine was used to stretch 50-mm short fibers. During the stretching process, the change process of the fibers was recorded by a camera. The stretching ended when the helical auxetic fibers broke. Subsequently, a computer software was used to analyze the experimental results and calculate the Poisson's ratio. The initial strain of the fibers with negative Poisson's ratio optimized by the method of the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -5.67. The negative Poisson's ratio effect of the fiber line was obvious, and it had a greater expansion effect. The short-cut fibers had high strength and stability, meeting the requirements for use in concrete.

[0059] Example 6: Preparation of polypropylene / twin-strand steel wire helical auxetic fibers with a diameter ratio of 2:1 and a wrapping angle of 15°; Using the preparation device of Example 1, 1 polypropylene filament with a diameter of 0.6 mm and 2 steel wires with a diameter of 0.3 mm were respectively selected as the core fiber and the wrapping fiber. The specific steps include: Step 1: Place the polypropylene fiber tube on the fiber-feeding roller 1. The polypropylene fibers on the polypropylene fiber tube sequentially pass through the pulley and the tension disk 4 under the rotation of the fiber-feeding roller 1 and are vertically fed into the center position at the bottom of the fiber-guiding tube 5. Then, the twin-strand steel wire is unwound from the steel wire tube. The twin-strand steel wire unwound from the steel wire tube passes through the converging hole 9 of the converging device and converges with the polypropylene fiber into a helical auxetic fiber 10, which is then wound around the first fiber-guiding roller 11, passes through the middle of the second fiber-guiding roller 12, and is placed on the guide rail strip 16. Finally, the formed helical auxetic fiber is transported through the fixed knife 17.

[0060] Step 2: Through the operation control system, the rotation speeds of the first fiber-guiding roller 11 and the second fiber-guiding roller 12 are 3 r / min, rotating three seconds per revolution and stopping for one second. The rotation speed of the base 6 is 15 r / min and it does not stop during the process. In this way, helical auxetic fibers can be obtained with the distance between the tightly wrapped segments being 50 mm.

[0061] Step 3: Align a certain section of the helical auxetic fiber already wound and formed on the guide rail strip 16 that has passed through the steel wire tight wrapping part with the fixed knife 17. Start the moving knife driving device and adjust its rotation speed to 3 r / min, making its rotation speed the same as that of the second fiber-guiding roller 12. The moving knife 18 cuts off the tightly wrapped segment of the helical auxetic fiber. The cut helical auxetic fibers fall into the packing box 21 from the discharge port 20, and the length of each fiber is 50 mm.

[0062] In order to verify the innovative contribution of the present invention, the fiber was subjected to a tensile test to observe the change in its diameter, thereby calculating the Poisson's ratio. First, a 50mm short fiber line was stretched using a universal stretching machine. During the stretching process, the fiber changes were recorded by a camera. The stretching was completed until the fiber broke. Subsequently, the experimental results were analyzed using computer software to calculate the Poisson's ratio. The fiber line optimized by the method of the present invention produces a negative Poisson's ratio. The initial strain of the fiber line is optimized to 2%, and the maximum negative Poisson's ratio is optimized to -8.27. The negative Poisson's ratio effect of the fiber line is obvious, and it has a greater expansion effect; the fiber line has high strength and stability, meeting the requirements for application in concrete.

[0063] Example 7: Preparation of polypropylene / double-strand steel wire spiral auxetic fibers with a diameter ratio of 4:1 and a wrapping angle of 15°; The preparation device of Example 1 is used, and one polypropylene filament with a diameter of 1.2 mm and two steel wires with a diameter of 0.3 mm are selected as the core fiber and the wrapping fiber respectively. The specific steps include: Step 1: Place a polypropylene fiber tube on a fiber feeding roller 1. The polypropylene fibers on the polypropylene fiber tube are vertically fed from the bottom center of the fiber guide tube 5 through the pulley and the tension disk 4 in sequence under the rotation of the fiber feeding roller 1; then unwind the double-strand steel wire from the steel wire tube, and the double-strand steel wire unwound from the steel wire tube passes through the convergence hole 9 of the convergence device and converges with the polypropylene fibers into a spiral expansion fiber 10, which is then wound on the first fiber guide roller 11, and then passes through the middle of the second fiber guide roller 12 and is placed on the guide rail 16. Finally, the formed spiral expansion fiber is transported and passed over the fixed knife 17.

[0064] Step 2: By operating the control system, the rotation speed of the first fiber guide roller 11 and the second fiber guide roller 12 is 2r / min, each rotation for three seconds and stop for one second, and the rotation speed of the base 6 is 20r / min without stopping, so that the spiral expansion fiber can be obtained with a spacing of 50mm between the tight hoop sections.

[0065] Step 3: Align a certain section of the spiral expansion fiber that has been wound on the guide rail 16 and is wound with a steel wire hoop with the fixed knife 17, start the movable knife driving device, adjust its rotation speed to 2r / min, and make its rotation speed the same as that of the second fiber guide roller 12, and the movable knife 18 cuts off the spiral expansion fiber hoop section, and the cut spiral expansion fiber 10 falls into the packaging box 21 from the discharge port 20, and each fiber has a length of 50mm.

[0066] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the helical auxetic fiber to observe its diameter change, and thus the Poisson's ratio was calculated. First, a universal tensile machine was used to stretch a 50-mm short fiber line. During the stretching process, the change process of the fiber was recorded by a camera. The stretching ended when the helical auxetic fiber broke. Subsequently, a computer software was used to analyze the experimental results and calculate the Poisson's ratio. The starting strain of the fiber line with a negative Poisson's ratio optimized by the method of the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -9.77. The negative Poisson's ratio effect of the fiber line was obvious, and it had a greater expansion effect. The fiber line had high strength and stability and met the requirements for use in concrete.

[0067] Example 8 Preparation of polyvinyl alcohol / twin-strand steel wire helical auxetic fiber with a diameter ratio of 3:1 and a wrapping angle of 15°; Using the preparation device of Example 1, 1 polyvinyl alcohol fiber with a diameter of 0.9 mm and 2 steel wires with a diameter of 0.3 mm were respectively selected as the core fiber and the wrapping fiber. The specific steps include: Step 1: Place the polyvinyl alcohol fiber tube on the fiber feeding roller 1. The polyvinyl alcohol fibers on the polyvinyl alcohol fiber tube pass through the pulley and the tension disc 4 in turn under the rotation of the fiber feeding roller 1 and are vertically fed into the bottom center position of the fiber guiding tube 5. Then, the twin-strand steel wire is unwound from the steel wire tube. The twin-strand steel wire unwound from the steel wire tube passes through the converging hole 9 of the converging device and converges with the polyvinyl alcohol fiber into a helical auxetic fiber 10, which is then wound around the first fiber guiding roller 11, passes through the middle of the second fiber guiding roller 12, and is placed on the guide rail strip 16. Finally, the formed helical auxetic fiber is transported through the fixed knife 17.

[0068] Step 2: Through the operation control system, the rotation speeds of the first fiber guiding roller 11 and the second fiber guiding roller 12 are 2 r / min. For every three seconds of rotation, it stops for one second. The rotation speed of the base 6 is 15 r / min and it does not stop during the process. Then, the helical auxetic fiber can be obtained and the distance between the spaced tight wrapping sections is 50 mm.

[0069] Step 3: Align a section of the helical auxetic fiber already wound and formed on the guide rail strip 16 that has been tightly wrapped with a metal wire with the fixed knife 17. Start the moving knife driving device and adjust its rotation speed to 2 r / min, making its rotation speed the same as that of the second fiber guiding roller 12. The moving knife 18 cuts off the tight wrapping section of the helical auxetic fiber. The cut helical auxetic fiber falls into the packing box 21 from the discharge port 20 and the length of each fiber is 50 mm.

[0070] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the helical auxetic fiber to observe its diameter change, and thus calculate the Poisson's ratio. First, a universal tensile machine was used to stretch a 50-mm short fiber line. During the stretching process, the change process of the fiber was recorded by a camera. The stretching ended when the helical auxetic fiber broke. Subsequently, a computer software was used to analyze the experimental results and calculate the Poisson's ratio. The starting strain of the fiber line with negative Poisson's ratio optimized by the method of the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -10.21. The negative Poisson's ratio effect of the fiber line was obvious, and it had a greater expansion effect. The fiber line had high strength and stability, meeting the requirements for use in concrete.

[0071] In an implementable manner, when the wrapping fiber is a flexible fiber, the following preparation steps are included: Step 1: Place the core fiber tube 2 on the fiber feeding roller 1. The core fiber 3 on the core fiber tube 2 sequentially passes through a pulley and a tension disc 4 under the rotation of the fiber feeding roller 1 and is vertically fed into the bottom center position of the fiber guiding tube 5. Then, unwind the wrapping fiber 8 from the wrapping fiber tube 7. The wrapping fiber 8 unwound from the wrapping fiber tube 7 passes through the converging hole 9 of the converging device and converges with the core fiber into a helical auxetic fiber 10, which is then wound around the first fiber guiding roller 11, passes through the middle of the second fiber guiding roller 12, and is placed on the guide rail bar 16. Finally, the helical auxetic fiber 10 is transported through above the fixed knife 17.

[0072] Step 2: By operating the control system, make the rotation speeds of the first fiber guiding roller 11 and the second fiber guiding roller 12 be 1 - 3 / min, and the rotation speed of the base 6 be 10 - 20 r / min and keep rotating without stopping throughout the process, then the helical auxetic fiber 10 can be obtained.

[0073] Step 3: Turn on the glue dripping device, place the helical auxetic fiber on the guide rail bar 16 under the needle 13 of the glue dripping device, and control the glue dripping device to make the needle 13 drip a drop of glue every 3 - 5 seconds, so that it adheres to the surface of the helical auxetic fiber, and then the formed helical auxetic fiber can be obtained.

[0074] Step 4: Align a section of the glued part of the helical auxetic fiber wound and formed on the guide rail bar 16 with the fixed knife 17, start the moving knife driving device, adjust its rotation speed to 1 - 3 r / min, make its rotation speed the same as that of the second fiber guiding roller, and the moving knife 18 cuts off the glued part of the helical auxetic fiber. The cut short helical auxetic fiber falls into the packing box 21 from the discharge port 20.

[0075] Preferably, in the said Step 3, the following steps are further included: When the epoxy resin dispensing device drips the glue 14 into the gap of the arc-shaped gear ring 27, the air pump 33 inflates the arc-shaped airbag 31 at this time, so that the sponge layer 32 contacts the surface of the helically expandable fiber 10. Then, the driving motor 29 drives the gear ring to rotate reciprocally, and the glue 14 is evenly coated on the surface of the helically expandable fiber 10. After the coating is completed, the driving motor 29 drives the arc-shaped gear ring 27 to reset to the initial position, and then the arc-shaped airbag 31 deflates to separate the sponge layer 32 from the surface of the helically expandable fiber 10.

[0076] Example 9: Preparation of polypropylene / single-strand carbon fiber helically expandable fiber with a diameter ratio of 3:1 and a winding angle of 15°; Using the preparation device of Example 1, 1 polypropylene fiber with a diameter of 0.9 mm and 1 carbon fiber with a diameter of 0.3 mm are respectively selected as the core fiber and the wrapping fiber: Step 1: Place the carbon fiber tube on the fiber feeding roller 1. The carbon fiber on the carbon fiber tube passes through the pulley and the tension disc 4 in turn under the rotation of the fiber feeding roller 1 and is vertically fed into the bottom center position of the fiber guiding tube 5; then the wrapping fiber 8 is unwound from the wrapping fiber tube 7. The wrapping fiber 8 unwound from the wrapping fiber tube 7 passes through the converging hole 9 of the converging device and converges with the carbon fiber into a helically expandable fiber 10, and then is wound on the first fiber guiding roller 11, passes through the middle of the second fiber guiding roller 12 and is placed on the guide rail strip 16. Finally, the helically expandable fiber 10 is transported through the top of the fixed knife 17.

[0077] Step 2: By operating the control system, the rotation speeds of the first fiber guiding roller 11 and the second fiber guiding roller 12 are 2 r / min, and the rotation speed of the base 6 is 15 r / min and does not stop during the whole process, then the helically expandable fiber can be obtained.

[0078] Step 3: Turn on the epoxy resin dispensing device, place the helically expandable fiber on the guide rail strip 16 under the needle 13 of the epoxy resin dispensing device, control the epoxy resin dispensing device to make the needle 13 drip a drop of glue every 3 seconds, and the distance between the dripping glue is 50 mm, then the formed helically expandable fiber can be obtained.

[0079] Step 4: Align a certain section of the glue-dropped part of the helically expandable fiber on the guide rail strip 16 that has been wound and formed with glue to the fixed knife 17, start the moving knife driving device, adjust its rotation speed to 2 r / min, and make its rotation speed the same as that of the second fiber guiding roller 12. The moving knife 18 cuts off the glue-dropped part of the helically expandable fiber, and the cut short helically expandable fiber falls into the packing box 21 from the discharge port 20 and the length of each fiber is 50 mm.

[0080] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the helical auxetic fiber to observe its diameter change, and thus calculate the Poisson's ratio. First, a universal tensile machine was used to stretch a 50-mm short fiber. During the stretching process, the change process of the fiber was recorded by a camera. The stretching ended when the helical auxetic fiber broke. Subsequently, a computer software was used to analyze the experimental results and calculate the Poisson's ratio. The initial strain of the fiber wire with a negative Poisson's ratio produced by the method optimized by the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -8.19. The negative Poisson's ratio effect of the fiber was obvious, and it had a greater expansion effect; the fiber wire had high strength and stability, meeting the requirements for use in concrete.

[0081] Example 10 Preparation of polypropylene / single-strand carbon fiber helical auxetic fiber with a diameter ratio of 3:1 and a wrapping angle of 15°; Using the preparation device of Example 1, one 0.9-mm-diameter polypropylene fiber and one 0.3-mm-diameter carbon fiber were respectively selected as the core fiber and the wrapping fiber: Step 1: Place the carbon fiber tube on the fiber-feeding roller 1. The carbon fiber on the carbon fiber tube passes through the pulley and the tension disk 4 in sequence under the rotation of the fiber-feeding roller 1 and is vertically fed into the bottom center position of the fiber-guiding tube 5 from the bottom; then the wrapping fiber 8 is unwound from the wrapping fiber tube 7. The wrapping fiber 8 unwound from the wrapping fiber tube 7 passes through the converging hole 9 of the converging device and converges with the carbon fiber into a helical auxetic fiber 10, which is then wound around the first fiber-guiding roller 11, passes through the middle of the second fiber-guiding roller 12, and is placed on the guide rail bar 16. Finally, the helical auxetic fiber 10 is transported through the fixed knife 17 from above.

[0082] Step 2: Through the operation control system, make the rotation speeds of the first fiber-guiding roller 11 and the second fiber-guiding roller 12 be 2 r / min, and the rotation speed of the base 6 be 15 r / min and keep rotating without stopping during the whole process, then the helical auxetic fiber 10 can be obtained.

[0083] Step 3: Turn on the glue-dropping device. Place the helical auxetic fiber on the guide rail bar 16 under the needle 13 of the glue-dropping device. Control the glue-dropping device to make the needle 13 drop a drop of glue every 4 seconds, and make the spacing between the dropped glue drops be 60 mm, then the formed helical auxetic fiber 10 can be obtained.

[0084] Step 4: Align a certain section of the glued part of the helical auxetic fiber that has been glued and wound on the guide rail bar 16 with the fixed knife 17. Start the moving knife driving device, adjust its rotation speed to 2 r / min, make its rotation speed the same as that of the second fiber-guiding roller. The moving knife 18 cuts off the glued part of the helical auxetic fiber. The cut short helical auxetic fiber falls into the packing box 21 from the discharge port 20, and the length of each fiber is 60 mm.

[0085] To verify the innovative contribution of the present invention, a tensile experiment was conducted on the helical auxetic fiber to observe its diameter change, so as to calculate the Poisson's ratio. First, a universal tensile machine was used to stretch a 60-mm short fiber. During the stretching process, the change process of the fiber was recorded by a camera. The stretching ended when the helical auxetic fiber broke. Subsequently, a computer software was used to analyze the experimental results and calculate the Poisson's ratio. The initial strain of the fiber with a negative Poisson's ratio optimized by the method of the present invention was optimized to 2%, and the maximum negative Poisson's ratio was optimized to -8.29. The negative Poisson's ratio effect of the fiber was obvious, and it had a greater expansion effect; the fiber wire had high strength and stability, meeting the requirements for use in concrete.

[0086] Table 1 Setting parameter table of each embodiment The principle of the present invention is that the core fiber 3 and the wrapping fiber 8 of the helical auxetic fiber 10 have a certain diameter ratio and tensile modulus ratio, and the wrapping fiber 8 is wound around the surface of the core fiber 3. When subjected to an axial tensile force, the wrapping fiber 8 with less elasticity is gradually straightened and tightened. During this process, the core fiber 3 with better elasticity gradually buckles from the straight state, so that the apparent contour of the composite fiber wire becomes larger. At this time, the fiber has a negative Poisson's ratio effect; and physical consolidation means that the wrapping fiber is helically wound in a way of tightly wrapping at an interval-fixed distance, which can effectively space-consolidate the core fiber 3: chemical adhesion means that after the helical auxetic fiber 10 is formed, glue is attached to its surface at an interval-fixed distance, which can bond the core fiber 3 and the wrapping fiber together, making its structure stable and not easy to untwist (because the flexible wrapping fiber 8 is easy to untwist, resulting in the inability to achieve consolidation by winding or poor consolidation effect).

[0087] In the present invention, the fiber guide roller, the base 6 and the fiber cutting mechanism respectively adopt different servo motors, and are equipped with a control system, so that the use of the motor can be controlled, and the rotation speed can be adjusted in real time according to personal needs. The different rotation speeds of the two can form a relative speed difference. On the one hand, the relative speed difference can be used to form a wrapping fiber tight hoop section on the spiral expansion fiber 10 line to ensure that the structure of the spiral expansion fiber 10 is stable and not easy to untwist. When the fiber guide roller rotates for three seconds, the base 6 operates normally, and the wrapping fiber is wound around the core fiber 3 according to the set wrapping angle. When the fiber guide roller stops for one second, the base 6 operates normally. At this time, the wrapping fiber is tightly wound around the core fiber 3. These turns of wrapping fiber tightly clamp the core fiber 3, making it not easy to untwist and the structure stable; on the other hand, the wrapping angle of the spiral expansion fiber 10 line can be controlled by the relative speed difference. When the transmission rate of the core fiber 3 is different from that of the wrapping fiber, the wrapping angle of the spiral expansion fiber 10 woven by the two is different. The guide bar 16 in the fiber cutting mechanism transports the woven spiral expansion fiber 10 to the mouth of the fixed knife 17. The gear connected to the moving knife 18 has the same speed and frequency as the first fiber guide roller 11, so as to ensure that the moving knife 18 accurately cuts the spiral expansion fiber 10 at the tight place every time, and ensures that the short spiral expansion fiber 10 with stable structure and consistent length can be obtained. The glue dripping device controls the glue dripping time and rate by controlling the compressed gas 23. The fiber feeding roller 1, the fiber guide roller and the guide bar 16 have the same transmission rate for the fiber and work at the same time.

[0088] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A preparation device for a helical tensile-expansion fiber with stable initial structure, characterized in that: It includes a core fiber feeding control mechanism, a wrapping fiber feeding control mechanism, a spiral stretching fiber forming and winding mechanism, and a cutting fiber mechanism arranged in sequence. Above one end of the cutting fiber mechanism, there is a glue dripping mechanism; The core fiber feeding control mechanism includes a core fiber tube, a fiber feeding roller, a tension disk, and a fiber guiding tube. The core fiber tube is placed on the fiber feeding roller. The fiber guiding tube is arranged above the tension disk. The end of the core fiber on the core fiber tube is wound around the tension disk and vertically fed into the wrapping fiber feeding control mechanism from the bottom of the fiber guiding tube; The wrapping fiber feeding control mechanism includes a base and several wrapping fiber tubes; the spiral stretching fiber forming and winding mechanism includes a converging hole, a first fiber guiding roller, and a second fiber guiding roller; the base is rotatably arranged. The fiber guiding tube is arranged in the middle of the base. Several wrapping fiber tubes are circumferentially and evenly arranged on the base. The converging hole is arranged above the wrapping fiber tubes. The wrapping fibers on several wrapping fiber tubes are spirally wrapped around the surface of the core fiber at the converging hole to form spiral stretching fibers. The end of the spiral stretching fiber is sequentially wound around the first fiber guiding roller and the second fiber guiding roller. The second fiber guiding roller drives the end of the spiral stretching fiber to move towards the cutting and limiting mechanism; The cutting fiber mechanism includes a guide rail bar, a moving knife, and a fixed knife. The guide rail bar is used to convey the spiral stretching fiber. The moving knife and the fixed knife are arranged behind one end of the guide rail bar away from the spiral stretching fiber to cut the spiral stretching fiber; The glue dripping mechanism is arranged above one end of the guide rail bar close to the spiral stretching fiber and includes a glue dripping syringe needle. The glue dripping syringe needle is used to drip the internal glue at a specified position of the spiral stretching fiber.

2. The manufacturing apparatus of a helical tensile-expansion fiber with stable initial structure according to claim 1, characterized in that: The cutting fiber mechanism further includes a driving device. The moving knife is connected to the driving device. There is a protective cover outside the cutting fiber mechanism. There is a discharge port at the rear end of the protective cover. Below the discharge port, there is a receiving box.

3. The manufacturing device of a helical tensile-expansion fiber with stable initial structure according to claim 1, characterized in that: The number of the first fiber guiding rollers is two. The two first fiber guiding rollers are arranged at the same height and rotate in opposite directions.

4. The preparation device of a helical tensile expansion fiber with stable initial structure according to claim 1, characterized in that: The number of the second fiber guiding rollers is two. The two second fiber guiding rollers are arranged vertically opposite to each other and rotate in opposite directions.

5. The preparation device of a spiral tensile expansion fiber with stable initial structure according to claim 1, characterized in that: The core fiber on the core fiber tube is made of one of polypropylene, polyvinyl alcohol, and glass fiber filaments. The number of the wrapping fiber tubes is 2 - 3, and the wrapping fibers on the wrapping fiber tubes are made of metal or flexible fibers.

6. The manufacturing apparatus of a helical stretchable fiber with stable initial structure according to claim 1, characterized in that: A glue - applying mechanism is provided between the epoxy resin dripping mechanism and the fiber cutting mechanism. The glue - applying mechanism includes an arc - shaped gear ring. A number of columnar gears are arranged on the outer side of the arc - shaped gear ring in a circumferentially uniform manner. The columnar gears are meshed with the arc - shaped gear ring. One end of the arc - shaped gear ring is provided with an arc - shaped plate. A number of driving motors are arranged on the arc - shaped plate. The driving motors are connected to one end of the columnar gears. An arc - shaped airbag is arranged on the inner side surface of the arc - shaped gear ring. One side of the arc - shaped airbag is fixed to the arc - shaped gear ring. A sponge layer is adhesively provided on the other side of the arc - shaped gear ring. An air pump is arranged on the arc - shaped plate. The output end of the air pump is communicated with the inside of the arc - shaped airbag through an air pipe.

7. The manufacturing apparatus of a helical tensile expansion fiber with stable initial structure according to claim 6, characterized in that: Blocks are arranged on the other ends of some of the columnar gears, and the blocks limit the translation of the arc - shaped gear ring.

8. A preparation method of an initially stable structure helically expandable fiber, applied to the preparation device described in any one of claims 1-7, characterized in that: When the wrapping fiber is made of metal, the preparation steps are as follows: Step 1: Place the core fiber tube on the fiber feeding roller. The core fiber on the core fiber tube passes through the tension disc under the rotation of the fiber feeding roller and is vertically fed into the center position at the bottom of the fiber guiding tube. Then, unwind the wrapping fiber from the wrapping fiber tube. The wrapping fiber unwound from the wrapping fiber tube passes through the converging hole and converges with the core fiber into a single spiral tension - expanding fiber, and then winds around the first fiber guiding roller, passes through the middle of the second fiber guiding roller and is placed on the guide rail strip. Finally, the formed spiral tension - expanding fiber is transported through above the fixed knife. Step 2: Through the operation control system, make the rotation speeds of the first fiber guiding roller and the second fiber guiding roller be 1 - 2 r / min. For every three - second rotation, stop for one second. The base continuously rotates, and its rotation speed is 10 - 20 r / min, then the spiral tension - expanding fiber can be obtained. Step 3: Align a certain section of the spiral tension - expanding fiber that has been wound and formed on the guide rail strip and passes through the part tightly wound by the metal wire with the fixed knife. Start the moving knife driving device, adjust its rotation speed to 1 - 2 r / min, making its rotation speed the same as that of the second fiber guiding roller. The moving knife cuts off the tightly wound section of the spiral tension - expanding fiber, and the cut short spiral tension - expanding fiber is discharged from the end of the guide rail strip.

9. A preparation method of an initially stable structure helical expansion fiber, which is applied to the preparation device described in any one of claims 1-7, and is characterized in that: When the wrapping fiber is a flexible fiber, the preparation steps are as follows: Step 1: Place the core fiber tube on the fiber feeding roller. The core fiber on the core fiber tube passes through the tension disc under the rotation of the fiber feeding roller and is vertically fed into the center position at the bottom of the fiber guiding tube. Then, unwind the wrapping fiber from the wrapping fiber tube. The wrapping fiber unwound from the wrapping fiber tube passes through the converging hole and converges with the core fiber into a single spiral tension - expanding fiber, winds around the first fiber guiding roller, passes through the middle of the second fiber guiding roller and is placed on the guide rail strip. Finally, the spiral tension - expanding fiber is transported through above the fixed knife. Step 2: Through the operation control system, make the rotation speeds of the first fiber guiding roller and the second fiber guiding roller be 1 - 3 r / min, and the rotation speed of the base be 10 - 20 r / min, and continuously rotate throughout the process, then the spiral tension - expanding fiber can be obtained. Step 3: Turn on the epoxy resin dripping device. Place the spiral tension - expanding fiber on the guide rail strip under the needle of the epoxy resin dripping device. Control the epoxy resin dripping device to make the needle drip a drop of glue every 3 - 5 seconds, so that it adheres to the surface of the spiral tension - expanding fiber, and the spiral tension - expanding fiber formed by dripping glue can be obtained. Step 4: Align the glue-dropped part of a certain section of the helical tensile-expansion fiber that has been wound with glue on the guide rail strip with the fixed knife. Start the moving knife driving device and adjust its rotation speed to 1 - 3 r / min, making its rotation speed the same as that of the second fiber roller. The moving knife cuts off the glue-dropped part of the helical tensile-expansion fiber, and the cut short helical tensile-expansion fiber is discharged from the end of the guide rail strip.

10. The preparation method of an initial stable structure helical tensile expansion fiber according to claim 9, characterized in that: In step 3, the following steps are further included: When the glue-dropping device drops glue into the helical tensile-expansion fiber from the notch of the arc-shaped gear ring, at this time, the air pump inflates the arc-shaped airbag to make the sponge layer contact the surface of the helical tensile-expansion fiber. Then, the driving motor drives the gear ring to rotate reciprocally to evenly coat the glue on the surface of the helical tensile-expansion fiber. After the coating is completed, the driving motor drives the arc-shaped gear ring to reset to the initial position, and then the arc-shaped airbag deflates to make the sponge layer separate from the surface of the helical tensile-expansion fiber.

Images