阅读说明：本技术 一种回转异形体预制体纱线张力联合控制试验方法 (Rotary special-shaped body preform yarn tension combined control test method ) 是由 单忠德 于肖 杨浩秦 廖万能 于 2021-08-08 设计创作，主要内容包括：本发明涉及纤维增加复合材料预制体三维织造领域,具体涉及一种回转异形体预制体纱线张力联合控制试验方法。内容为在异形回转体三维织造过程中,对张力大小波动范围进行精确控制,以减少纱线在张力作用下的磨损,并补偿纱线在织造过程中的长度变化,保证预制体内部质量均匀性。实现回转异形体预制体织造过程中的张力控制,确保大范围的纱线整体张力的可控性,使张力显著降低并保持恒定,能够减少织造过程中张力不均、张力突变等问题的出现,有利于提高回转异形体三维织造过程的可控化、自动化程度。(The invention relates to the field of three-dimensional weaving of fiber reinforced composite material preforms, in particular to a combined control test method for yarn tension of a rotary special-shaped preform. The method comprises the steps of accurately controlling the fluctuation range of the tension in the three-dimensional weaving process of the special-shaped revolving body so as to reduce the abrasion of yarns under the action of the tension, compensate the length change of the yarns in the weaving process and ensure the internal quality uniformity of the prefabricated body. The tension control in the weaving process of the rotary special-shaped body preform is realized, the controllability of the integral tension of the yarn in a large range is ensured, the tension is obviously reduced and kept constant, the problems of uneven tension, sudden change of the tension and the like in the weaving process can be reduced, and the controllability and the automation degree of the three-dimensional weaving process of the rotary special-shaped body are favorably improved.)

1. A yarn tension combined control test method for a revolving profile body preform is characterized by comprising the following parts:

a: designing a test matrix of the influence of a yarn carrier path on the tension and the tension fluctuation of a multi-head yarn carrier from the control of the weaving yarn tension;

b: an opening pair yarn tension control part for performing optimization guidance on the action range of the opening device according to the tension change; designing a test matrix for controlling influence of an opening mode on yarn tension;

c, a yarn control part of the densification unit; obtaining the corresponding relation between the force applied by the densification unit and the yarn tension; the strength of the force applied by the densification unit is directly expressed as different spindle lengths of the unit cell, so that the performance of the composite material with different structures and different spindle lengths can be obtained by designing a yarn tension control test matrix of the densification unit so as to guide the strength of the force applied by the densification unit, and further a data basis is provided for the yarn tension control design;

d: the circumferential/radial yarn implantation system has a part for influencing the tension of the knitting yarns: the yarn implanting system is divided into a circumferential/radial yarn implanting system, and the implantation of yarns in different directions and different types of yarns has different binding forces on the knitting yarns and different influences on the tension of the knitting yarns; designing a yarn implantation system to control a test matrix of yarn tension, and realizing the coordination and matching of the yarn implantation system and a yarn weaving tension system to meet the requirements of a digital weaving process;

and E, researching the influence of yarn tension on yarn damage in the weaving process, establishing the corresponding relation between the yarn tension, fiber damage and material performance, designing a tensile strength test matrix of the yarn bundle in various states, a test matrix of yarn characteristic parameters and raw material types to a design value and a fluctuation range of yarn control, and obtaining the combined control method.

2. The method for testing the yarn tension of the revolving profile body preform in combination according to claim 1, wherein in the section A: in the matrix of properties of the composite material for the different yarn tensions: the method comprises the following steps of testing a performance item, setting a tension range and weaving performance of yarn bundles; the performance test items comprise yarn bundle weaving performance, stretching, high-temperature stretching, compressing, high-temperature compressing, shearing, high-temperature shearing and stretching in the thickness direction.

3. The method for testing the yarn tension of the revolving profile body preform in combination according to claim 1, wherein the part B: the test matrix for controlling influence of the opening mode on the yarn tension comprises the opening mode, mechanical property test and microscopic analysis; wherein the opening means comprises a circumferential opening and a radial opening.

4. The method for testing the yarn tension of the revolving profile body preform in combination according to claim 1, wherein the section C comprises: the densification unit yarn tension control test matrix comprises a performance test, a prefabricated body structure and a pattern length, wherein the performance test comprises stretching, high-temperature stretching, compressing, high-temperature compressing, shearing, high-temperature shearing and stretching in the thickness direction.

5. The method for testing the yarn tension of the revolving profile body preform in combination according to claim 1, wherein the section D: the yarn tension control test matrix of the yarn implantation system comprises a weaving mode, a test item and a forming structure; wherein the weaving mode adopts mixed weaving, and the test items comprise stretching, high-temperature stretching, compressing, high-temperature compressing, interlaminar shearing, high-temperature interlaminar shearing and stretching in the thickness direction; the forming structure comprises a three-dimensional four-direction, a three-dimensional five-direction, a three-dimensional six-direction and a three-dimensional seven-direction.

6. The method for testing the yarn tension of the revolving profile body preform in combination according to claim 1, wherein the section E: the method comprises the following steps of (1) carrying out a tensile strength test matrix on yarn bundles in various states, and researching the trend of tensile strength change of the twisted and braided yarns by carrying out a tensile test on each yarn (original, twisted and braided); the number of effective samples in each group of tests is not less than 7.

7. The method for testing the yarn tension joint control of the rotary profile body preform according to claim 1, wherein the yarn characteristic parameters and the test matrix of the types of the raw materials are used for testing the mechanical properties of three-dimensional woven preform composite materials with different raw materials and different forming structure modes, wherein the mechanical properties comprise seven mechanical properties of stretching, high-temperature stretching, compressing, high-temperature compressing, stress shearing, high-temperature stress shearing and thickness direction stretching.

Technical Field

The invention relates to the field of three-dimensional weaving of fiber reinforced composite material preforms, in particular to a combined control test method for yarn tension of a rotary special-shaped preform.

Background

The manufacturing of the three-dimensional woven preform is a novel weaving technology, yarns are distributed in two mutually perpendicular directions along the warp direction and the weft direction in a three-dimensional space and are interwoven to form an integral structure, a composite material member manufactured by the three-dimensional woven preform as a high-performance composite material reinforcement has the advantages of light weight, high strength, excellent mechanical property and the like, is widely applied in various fields such as aerospace, national defense and military industry, transportation, energy and the like at present, and is continuously expanded to the civil field.

With the development of the three-dimensional weaving and forming technology of the composite material preform, the requirements of the application and the rapid and low-cost manufacture of the composite material three-dimensional preform based on the rotary irregular body are urgent, and the quality stability requirement of the preform forming is higher and higher. The conventional method of directly detecting and controlling the tension in the process by using a tension sensor has the defects of large fiber abrasion and incapability of effectively compensating the yarn length in the rotary special-shaped body weaving process.

The yarn tension control in the digital three-dimensional weaving principle prototype is mainly controlled by a yarn carrier yarn-retracting mechanism, but in different process procedures, mechanisms such as a shedding mechanism, a densification unit, a circumferential/radial yarn implantation system and the like can influence the yarn tension, and the tension control range and the fluctuation condition have great influence on the feasibility of the weaving process and the final composite performance of a prefabricated body.

Disclosure of Invention

In order to solve the problems, the invention discloses a combined control test method for yarn tension of a revolving special-shaped body preform, which is used for respectively researching the influence of a yarn carrier path on the tension and the tension fluctuation of a multi-head yarn carrier from the control of the yarn weaving tension, guiding the tension control and fluctuation range and breaking through the tension stability control technology. And secondly, the influence of the opening device, the densification unit and the circumferential/radial yarn implantation system on the tension of the knitting yarns is researched, and the yarn tension time sequence accurate control technology is broken through. Finally, the influence of yarn tension on yarn damage in the knitting process is deeply researched, the corresponding relation between the yarn tension, fiber damage and material performance is established, the design value and the fluctuation range of yarn control are guided, and finally the digital three-dimensional low-damage knitting technology is overcome.

A combined control test method for yarn tension of a revolving profile body preform comprises the following parts:

a: designing a test matrix of the influence of a yarn carrier path on the tension and the tension fluctuation of a multi-head yarn carrier from the control of the weaving yarn tension;

b: an opening pair yarn tension control part for performing optimization guidance on the action range of the opening device according to the tension change; designing a test matrix for controlling influence of an opening mode on yarn tension;

c, a yarn control part of the densification unit; obtaining the corresponding relation between the force applied by the densification unit and the yarn tension; the strength of the force applied by the densification unit is directly expressed as different spindle lengths of the unit cell, so that the performance of the composite material with different structures and different spindle lengths can be obtained by designing a yarn tension control test matrix of the densification unit so as to guide the strength of the force applied by the densification unit, and further a data basis is provided for the yarn tension control design;

d: the circumferential/radial yarn implantation system has a part for influencing the tension of the knitting yarns: the yarn implanting system is divided into a circumferential/radial yarn implanting system, and the implantation of yarns in different directions and different types of yarns has different binding forces on the knitting yarns and different influences on the tension of the knitting yarns; a yarn implantation system is designed to control a test matrix of yarn tension, and the yarn implantation system and a yarn weaving tension system are coordinated and matched to meet the requirements of a digital weaving process.

And E, researching the influence of yarn tension on yarn damage in the weaving process, establishing the corresponding relation between the yarn tension, fiber damage and material performance, designing a tensile strength test matrix of the yarn bundle in various states, a test matrix of yarn characteristic parameters and raw material types to a design value and a fluctuation range of yarn control, and obtaining the combined control method.

The invention further improves that: in the section A: in the matrix of properties of the composite material for the different yarn tensions: the method comprises the following steps of testing a performance item, setting a tension range and weaving performance of yarn bundles; the performance test items comprise yarn bundle weaving performance, stretching, high-temperature stretching, compressing, high-temperature compressing, shearing, high-temperature shearing and stretching in the thickness direction.

The invention further improves that: the part B is as follows: the test matrix for controlling influence of the opening mode on the yarn tension comprises the opening mode, mechanical property test and microscopic analysis; wherein the opening means comprises a circumferential opening and a radial opening.

The method for testing the yarn tension of the revolving profile body preform in combination according to claim 1, wherein the section C comprises: the densification unit yarn tension control test matrix comprises a performance test, a prefabricated body structure and a pattern length, wherein the performance test comprises stretching, high-temperature stretching, compressing, high-temperature compressing, shearing, high-temperature shearing and stretching in the thickness direction.

The invention further improves that: the part D: the yarn tension control test matrix of the yarn implantation system comprises a weaving mode, a test item and a forming structure; wherein the weaving mode adopts mixed weaving, and the test items comprise stretching, high-temperature stretching, compressing, high-temperature compressing, interlaminar shearing, high-temperature interlaminar shearing and stretching in the thickness direction; the forming structure comprises a three-dimensional four-direction, a three-dimensional five-direction, a three-dimensional six-direction and a three-dimensional seven-direction.

The invention further improves that: the part E: the method comprises the following steps of (1) carrying out a tensile strength test matrix on yarn bundles in various states, and researching the trend of tensile strength change of the twisted and braided yarns by carrying out a tensile test on each yarn (original, twisted and braided); the number of effective samples in each group of tests is not less than 7.

The invention further improves that: the yarn characteristic parameters and the test matrix of the types of the raw materials test the mechanical properties of the three-dimensional woven preform composite material with different raw materials and different forming structure modes, and the mechanical properties comprise seven mechanical properties of stretching, high-temperature stretching, compressing, high-temperature compressing, stress shearing, high-temperature stress shearing and stretching in the thickness direction.

The invention has the beneficial effects that:

(1) the combined control test method for yarn tension of the rotary special-shaped body preform, provided by the invention, realizes tension control in the weaving process of the rotary special-shaped body preform, ensures the controllability of the integral tension of the yarn in a large range, obviously reduces and keeps the tension constant, can reduce the problems of uneven tension, sudden tension change and the like in the weaving process, and is beneficial to improving the controllability and the automation degree of the three-dimensional weaving process of the rotary special-shaped body.

(2) Establishing a corresponding relation among yarn tension, fiber damage and material performance, guiding a design value and a fluctuation range of yarn control, and finally overcoming the digital three-dimensional low-damage weaving technology.

Drawings

FIG. 1 is a technical route diagram of yarn combination control.

Detailed Description

The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

As shown in fig. 1, the present embodiment is a method for testing yarn tension of a revolving profile body preform in a combined control manner,

from the tension control of the knitting yarns, the influence of the paths of the yarn carriers on the tension and the tension fluctuation of the multi-head yarn carrier are respectively researched, the tension control and fluctuation range are guided, and the tension stability control technology is broken through. And secondly, the influence of the opening device, the densification unit and the circumferential/radial yarn implantation system on the tension of the knitting yarns is researched, and the yarn tension time sequence accurate control technology is broken through. Finally, the influence of yarn tension on yarn damage in the knitting process is deeply researched, the corresponding relation between the yarn tension, fiber damage and material performance is established, the design value and the fluctuation range of yarn control are guided, and finally the digital three-dimensional low-damage knitting technology is overcome.

(1) Knitting yarn tension control

When the digital three-dimensional weaving equipment is used for weaving the rotary special-shaped body preform, a weaving mode from the upper end of the die to the lower end of the die is adopted, so that yarns are attached to the core die due to too small yarn tension in the digital three-dimensional weaving, yarn openings are unclear, circumferential and radial yarns are difficult to implant, and the weaving of the preform is difficult to complete. When the yarn tension is large, the yarn opening is difficult to close, the circumferential and radial yarns are difficult to densify after being implanted, and the prefabricated part cannot complete size control. The yarn tension not only influences the feasibility of the preform weaving process, but also greatly influences the internal structure of the preform. The yarn tension is controlled in a weaving process range, the influence of a motion path of a yarn carrier on the yarn tension is researched, different yarn tensions are designed, the influence of the yarn tension on the weaving angle and the unit cell form of the yarn inside the unit cell of the prefabricated body is researched, and the influence of the tension on the mechanical property of the composite material is further researched. On the basis of the research, the tension fluctuation ranges of different yarn carriers are researched, and the condition that the tension is uneven in the weaving process is avoided. The sample requirements and amounts are shown in the table below.

Matrix of different yarn tension versus composite performance test:

the matrix of the performance test of the composite material by different yarn tensions is obtained:

when the yarn tension is 1-3N, the mechanical property of the final finished piece is excellent, fiber damage can be caused by overlarge tension, the mechanical property is reduced, and the prefabricated body is not easy to form due to the overlarge tension.

(2) Opening device influencing yarn tension

The control of the yarn tension in the digital three-dimensional weaving equipment is a combined multi-system combined control, and besides being mainly controlled by a yarn carrier system, the opening device, the yarn implantation system and the densification unit can also influence the yarn tension. For the shedding device, two modes of circumferential shedding and radial shedding exist, firstly, when the shedding device is circumferentially shed, yarns need to be respectively released and collected by layer-by-layer weaving yarns, the tension difference of the weaving yarn shed is large due to the introduction of circumferential yarns in different layers, and therefore the influence of the circumferential shedding device on the yarn tension in different thickness directions needs to be researched. Secondly, the radial opening causes uneven yarn tension, the larger the opening range is, the more the influenced yarn tension changes, the larger the fluctuation range of the yarn tension is, the larger the influence is on the uniformity of the prefabricated body, and further the material performance is influenced, so that the optimization guidance needs to be carried out on the action range of the opening device according to the tension change. The test sample amounts are shown in the table below.

Test matrix for influence of opening mode on yarn tension control

The experimental matrix for the influence of the opening mode on the yarn tension control is obtained: during circumference opening, weaving yarn tension is uneven, and when yarn tension is poor to be greater than 3N, the loose region of part appears in prefabricated body inner structure, and some fibre receives serious damage, and during radial opening, yarn fluctuation range is big, and when yarn tension undulant exceedes 3N, the fibre is impaired seriously, and these two kinds of circumstances can all produce adverse effect to final prefabricated body's performance, need carry out real-time optimization to opening device's action range according to tension change, and control opening size keeps tension invariable.

(3) Effect of densification Unit on yarn tension control

In the weaving process, the preform densification unit and the combined system thereof apply certain force to the yarns which form interweaving according to the interweaving rule, so that the preform is densified, and the precise control of the shape, the size and the position of the single cell of the preform can be realized by adjusting the size and the direction of the applied force in the process, so that the volume fraction ratio of fibers in different directions in the preform is regulated and controlled, and the comprehensive performance of the composite material is further influenced. However, since the magnitude of the applied force has a large influence on the yarn tension during the operation of the densification unit, and the large applied force of the densification unit even affects the progress of the knitting process, it is necessary to study the correspondence between the applied force of the densification unit and the yarn tension. The force applied by the densification unit is directly expressed as different knot lengths of the unit cell, so that the force applied by the densification unit can be guided by researching the performance of the composite material with different structures and different knot lengths, and a data basis is further provided for the yarn tension control design. The test matrix is shown in the table below.

The densification unit yarn tension control test matrix is as follows:

the densification unit obtains a yarn tension control test matrix: the smaller the preform spline length is, the higher the preform fiber content is, but the larger the tension applied to the yarn by the densification unit is, the larger the damage to the fiber is caused while the preform strength is improved, so that the spline length is not too large or too small, the spline length with a medium length (2-3cm) should be selected, and at the moment, the preform part has a certain fiber content and has less damage to the fiber.

(4) Yarn implantation system effect on yarn tension control

The yarn implanting system is divided into a circumferential/radial yarn implanting system, and the implantation of yarns in different directions and different types of yarns has different binding force on the knitting yarns and different influence on the tension of the knitting yarns. The influence of implantation of different yarns in the circumferential direction and the radial direction on the tension control of the knitting yarns is researched, and the yarn implantation system and the knitting yarn tension system are coordinated and matched to meet the requirements of a digital knitting process. The test matrix is shown in the table below.

Yarn tension control test matrix of yarn implantation system

The yarn tension control test matrix is obtained through a yarn implantation system, the circumferential/radial implantation of the yarns has different influences on the tension of the woven yarns, and the yarn implantation mode needs to be adjusted in real time so as to ensure constant yarn tension and the performance of the prefabricated body.

(5) Fiber damage to material properties

The yarn is abraded by a weaving mechanism and among yarns in the weaving process of the prefabricated body, the larger the yarn tension is, the farther the relative distance between the weaving opening position and the yarn carrier is, the more serious the yarn abrasion condition is, and the analysis of the damage of the fiber in the weaving process has guiding significance on the design and tension adjustment of a weaving structure; the yarns in the preform serve the primary load-bearing function, and when the composite is subjected to an external load, stresses are transmitted from the matrix to the fibers, which can cause failure of the composite if the load exceeds the ultimate tensile strength of the fibers. Therefore, the characteristics of the yarns forming the preform and the degree of damage during the knitting process greatly affect the performance of the composite material. The content aims at digital three-dimensional low-damage weaving, the performances of the prefabricated body and the composite material under the matching relationship of yarn parameters such as yarn twist, yarn direction and the like and yarn tension are researched, the joint control of the yarn tension is finally realized, and the low-damage weaving of the prefabricated body is completed.

In the three-dimensional weaving of the yarn, factors such as bending, deformation, friction and the like cause the section shape and the fiber appearance of the yarn to be obviously changed. Yarn twisting is one of the common methods for improving the weaving performance of high-performance fibers, and in order to explore the damage condition of the yarn in the twisting and weaving processes, the trend of the tensile strength change of the yarn after twisting and weaving is researched by performing a tensile test on each yarn (original, twisted and woven). Tensile strength of the yarn at various conditions is tested in the following table. In order to ensure the accuracy of test data, the number of effective samples in each group of tests is not less than 7.

Tensile strength test matrix of yarn bundles in various states

The mechanical properties of the three-dimensional woven preform composite material with different raw materials and different forming structure modes are tested according to related standard tests in the project, and the mechanical properties comprise seven mechanical properties of stretching, high-temperature stretching, compressing, high-temperature compressing, stress shearing, high-temperature stress shearing and stretching in the thickness direction. And data support is provided for researching the influence rule of the preform parameter change on the performance of the composite material. The yarn property parameters and the types of raw materials were tested as shown in the following table.

Test matrix of yarn characteristic parameters and types of raw materials

Damage to different fibers has a serious adverse effect on the mechanical properties of the preform. For quartz fiber, the 2-3N yarn tension is more than the 1-2N fiber yarn tension, which reduces the performance of the preform by more than 20%, while for carbon fiber, the 2-3N yarn tension is less than the 1-2N fiber yarn tension, which reduces the performance of the preform by only 10%.

The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.