WO2023045039A1

WO2023045039A1 - Preparation method for piezoelectric yarn reinforced resin-based composite material

Info

Publication number: WO2023045039A1
Application number: PCT/CN2021/128693
Authority: WO
Inventors: 樊威; 康敬玉; 刘涛; 陆琳琳; 陆瑶; 李博; 张雨晗; 孙岩; 姚莹; 张聪
Original assignee: 西安工程大学
Priority date: 2021-09-26
Filing date: 2021-11-04
Publication date: 2023-03-30
Also published as: CN113831687B; CN113831687A

Abstract

A preparation method for a piezoelectric yarn reinforced resin-based composite material, comprising: preparing a piezoelectric core-spun yarn of which the core layer is carbon fiber and the skin layer is a piezoelectric polymer fiber net by utilizing an electrostatic spinning parallel electrode method; acquiring a piezoelectric yarn of which the outer layer is carbon fiber, the middle layer is a piezoelectric polymer fiber net and the core layer is carbon fiber by utilizing two-dimensional weaving; coating the piezoelectric yarn with a PU film to obtain PU-coated piezoelectric yarn; acquiring a woven fabric with carbon fibers as warp yarns and piezoelectric yarns wrapped by the carbon fibers and PU as weft yarns by utilizing three-way orthogonal weaving; and acquiring the piezoelectric yarn reinforced resin-based composite material by means of vacuum-assisted resin transfer molding technology. The piezoelectric yarn is implanted into the composite material, and the mechanical properties of the composite material are monitored by means of the piezoelectric change of the piezoelectric yarn in the composite material along with the increase of strain for the health monitoring of damage.

Description

A kind of preparation method of piezoelectric yarn reinforced resin matrix composite material

technical field

The invention relates to the field of intelligent composite materials, in particular to a method for preparing piezoelectric yarn-reinforced resin-based composite materials.

Background technique

Composite materials have the advantages of light weight, high specific strength, large specific modulus, and high fatigue resistance, and are widely used in modern aerospace, engineering, and transportation fields. Nevertheless, composite materials will be affected by factors such as aging, fatigue, and external impact during long-term service. These factors often cause structural defects of materials, affect the service life of materials, and even cause major economic losses and threats in severe cases. User's personal safety. Therefore, real-time online health monitoring for the structure of composite materials can not only improve the service life of materials, save maintenance costs, but also effectively prevent accidents. The emergence of smart materials provides a new path for real-time online monitoring of the structural health of materials.

The so-called smart material refers to the system to regulate various functions inside the material, which can perceive and respond to the environment, and has the functional characteristics of self-diagnosis and self-repair. According to the functional characteristics of smart materials, they can be divided into shape memory alloys, optical fibers, piezoelectric, piezoresistive, electrovariant, electric (magnetic, thermal) stretchable materials, and optical fiber sensors. These materials can automatically change their size, shape, internal resistance, vibration frequency, stiffness and other properties according to changes in the external environment (such as temperature, electromagnetic field, etc.), which can meet the application requirements of different occasions.

At present, it is becoming more and more difficult for single-component materials to meet people's production and living needs. It is often required that one material has multiple functions at the same time, which requires mixing two or more materials to achieve it, the so-called composite material. Piezoelectric materials have also gained new opportunities due to the emergence of material composite technology. After composite design and preparation, the performance of piezoelectric composite materials has a qualitative leap compared with single piezoelectric materials. The document "Shipway NJ, Barden TJ, Huth waite P, et al.Performance Based Modifications of Random Forest to Perform Automated Defect Detection for Fluorescent Penetrant Inspection" mentions that non-destructive testing methods such as ultrasonic detection, eddy current testing and penetrant testing are used to detect Traditional methods of damage to the internal structure of materials, they have been applied in some industrial fields. However, with the development of science and technology, detection technology has gradually tended to real-time online monitoring, and the above methods are all offline detection, which can no longer meet the needs of the rapid development of science and technology today. The literature "Ostachowicz W, Soman R, Malinowski P. Optimization of sensor placement for structural health monitoring: a review" mentioned that integrating piezoresistive sensors into materials is the main means to achieve online health monitoring of materials, but piezoresistive sensors are in Under severe conditions such as high temperature, cross-effects are prone to occur, which affects its accuracy; on the other hand, piezoresistive sensors generally require external drives to work, which does not meet the modern concept of sustainable development.

Contents of the invention

Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a method for preparing piezoelectric yarn-reinforced resin-based composite materials.

The technical solution of the present invention to solve the technical problem is to provide a method for preparing a piezoelectric yarn-reinforced resin-based composite material, which is characterized in that the method comprises the following steps:

Step 1. Using carbon fiber as the core layer and piezoelectric polymer solution as the spinning solution, the piezoelectric polymer is spun on the outer layer of the carbon fiber by the electrospinning parallel electrode method to prepare the core layer as carbon fiber and the skin layer as piezoelectric Piezoelectric core-spun yarns of polymeric webs;

Step 2. Use the piezoelectric core-spun yarn prepared in step 1 as the core yarn and carbon fiber as the braided yarn to carry out two-dimensional weaving to obtain a piezoelectric composite with carbon fiber as the outer layer, piezoelectric polymer fiber mesh as the middle layer, and carbon fiber as the core layer. yarn;

Step 3, coating the piezoelectric yarn prepared in step 2 with a PU film to obtain a PU-wrapped piezoelectric yarn;

Step 4, carrying out three-way orthogonal weaving of the PU-wrapped piezoelectric yarn and carbon fiber prepared in step 3, to obtain a woven fabric with carbon fiber as warp yarn and carbon fiber and PU-wrapped piezoelectric yarn as weft yarn;

Step 5, impregnating the woven fabric prepared in step 4 into an epoxy resin matrix, and then curing the woven fabric impregnated with epoxy resin by vacuum-assisted resin transfer molding technology to obtain a piezoelectric yarn-reinforced resin-based composite material.

Compared with the prior art, the present invention has the beneficial effects of:

(1) The present invention implants the piezoelectric yarn into the composite material, and monitors the mechanical properties of the composite material through the piezoelectric change of the piezoelectric yarn in the composite material with the increase of the strain, that is, the composite material is in service Health monitoring of in-process injuries.

(2) The close integration of PVDF yarn sensor and carbon fiber can realize timely perception and feedback of hidden dangers such as structural abnormalities and damages, thereby effectively improving the reliability of composite materials and providing a theoretical and practical basis for the promotion and application of intelligent composite materials.

(3) The electrospinning technology adopted in this method has simple equipment, low cost, and simple operation, and the electrospinning process itself has a polarization effect, eliminating the subsequent polarization step.

(4) Carbon fibers have good electrical conductivity, and are used as electrodes for collecting piezoelectric signals, and have good flexibility. Carbon fiber can smoothly export the piezoelectric signal generated by PVDF, so that it can be more conveniently applied to the weaving of piezoelectric fabrics.

Description of drawings

Fig. 1 is the surface electron micrograph of the piezoelectric core-spun yarn prepared in Example 1 of the present invention;

Fig. 2 is the cross-sectional electron micrograph of the piezoelectric core-spun yarn prepared in Example 1 of the present invention;

Fig. 3 is a graph showing the relationship between mechanical properties and piezoelectric properties of the composite material prepared in Example 1 of the present invention.

Detailed ways

Specific examples of the present invention are given below. The specific embodiments are only used to further describe the present invention in detail, and do not limit the protection scope of the claims of the present application.

The present invention provides a kind of preparation method (abbreviation method) of piezoelectric yarn reinforced resin-based composite material, it is characterized in that, this method comprises the following steps:

Step 1. Using carbon fiber as the core layer and piezoelectric polymer solution as the spinning solution, the piezoelectric polymer is spun on the outer layer of the carbon fiber by the electrospinning parallel electrode method to prepare the core layer as carbon fiber and the skin layer as piezoelectric polymerization Piezoelectric core-spun yarns for fiber webs;

Preferably, in step 1, the piezoelectric polymer solution is a solution prepared from a piezoelectric polymer and a solvent; the piezoelectric polymer is PVDF, PAN or PA11.

When the piezoelectric polymer adopts PVDF, the solvent is a mixed solvent of N,N-dimethylformamide and acetone. The specific preparation method is: at room temperature, take PVDF powder and dissolve it in N,N-dimethylformamide and In acetone, under sealed conditions, magnetically stir at 50-60° C. for 6-8 hours. After heating, take it out and let it stand to cool to room temperature to obtain a PVDF solution with a concentration of 8-13 wt%.

When PAN is used as the piezoelectric polymer, the solvent is N,N-dimethylformamide. The specific preparation method is: at room temperature, dissolve PAN powder in N,N-dimethylformamide, and then , magnetic stirring at 50-60°C for 6-8 hours, after heating, take it out and let it stand to cool to room temperature to obtain a PAN solution with a concentration of 8-12wt%.

Preferably, in step 1, the electrospinning parallel electrode method specifically includes: fixing the syringe containing the piezoelectric polymer solution in the syringe pump of the electrospinning equipment, adjusting the electrospinning parameters, and connecting the spinnerets to the power supply respectively Positive and negative electrodes, the solution is accelerated at the apex of the Taylor cone of the spinneret under the action of the electric field force, and under the action of a sufficiently large electric field force, the surface tension is overcome to spray the fine stream, so that the fine stream forms a fiber web at the bell mouth; at the same time After the carbon fiber passes through the bell mouth, it is pulled by the winding roller, so that the piezoelectric polymer fiber is evenly coated on the carbon fiber through the rotating bell mouth, and collected on the winding roller to obtain carbon fiber as the core layer, piezoelectric polymer The fiber net is the piezoelectric core-spun yarn of the cortex, and it is dried in an oven. The purpose of drying is to make the solvent volatilize more thoroughly;

Electrospinning parameters are: the flow rate of spinning solution is 0.4-0.6ml/h, the spinning voltage is 4.5-5kV, the spinning distance is 8-10cm, the distance between two needles is 10-12cm, and the speed of winding roller is 0.1-0.3 mm/s, the bell mouth speed is 400~450rpm, the spinning environment temperature is 20±2℃, the relative humidity of the spinning environment is 60±5%; the drying temperature is 60~100℃, and the drying time is 2~4h.

Step 2. Use the piezoelectric core-spun yarn prepared in step 1 as the core yarn, and use carbon fiber as the braided yarn (i.e., wrapping yarn), use a two-dimensional knitting machine to perform two-dimensional weaving, and coat the outer side of the piezoelectric core-spun yarn with carbon fiber Prepare a two-dimensional braided core-spun yarn to obtain a piezoelectric yarn in which the outer layer is carbon fiber, the middle layer is a piezoelectric polymer fiber mesh, and the core layer is carbon fiber;

Preferably, in step 2, the specific operation of two-dimensional weaving is: 1) determine the number of spindles used according to the yarn structure, usually select an even number of spindles, the number of spindles selected in this embodiment is 4 spindles; 2) according to the number of spindles selected , prepare to wind a corresponding number of carbon fiber bobbins, that is, the bobbins are all wrapped with carbon fibers, so that they can be placed on the yarn carrier during weaving; the bottom of the bobbins is a right-angle tooth shape, and this structure can meet the requirements of weaving yarns when weaving carbon fiber bobbins. Unwinding of carbon fiber; therefore, according to the direction of the tooth shape, choose a reasonable winding direction to avoid poor unwinding during weaving; 3) Place the carbon fiber bobbin on the yarn carrier; for the weaving process of the carbon fiber bobbin with 4 spindles , the carbon fiber bobbins should be evenly placed on two motion trajectories, one is woven clockwise and the other is woven counterclockwise; 4) A tension device is placed under the two-dimensional knitting machine; the piezoelectric package as the core yarn After the core yarn obtains a certain tension through the device, it is fed along the axial direction of the final formed yarn; passes through the center of the orbital disc, passes through the yarn forming device together with the braided yarn, and is fixed on the extraction mechanism; Rotate to realize the weaving of core-spun yarn.

Step 3. Completely cover the piezoelectric yarn prepared in step 2 with a PU film to obtain a PU-wrapped piezoelectric yarn; prevent the epoxy resin from being immersed in the piezoelectric yarn during the curing process, causing it to lose the piezoelectric signal , PU plays the role of protecting the piezoelectric yarn;

Preferably, in step 3, the coating is to lay the PU film flat, put the piezoelectric yarn on one end of the PU film, and wrap the piezoelectric yarn in the PU film by winding.

Preferably, in step 3, the preparation method of the PU film is: using the PU solution as the spinning solution, and using the electrospinning equipment to prepare the PU fiber film; the receiving device is a receiving roller rotating around an axis;

PU solution is a solution made of polyurethane and N,N-dimethylformamide as raw materials. The specific preparation method is: at room temperature, take PU particles and dissolve them in N,N-dimethylformamide, and then , magnetic stirring at 50-60° C. for 6-8 hours, after heating, take it out and let it stand to cool to room temperature to obtain a PU solution with a concentration of 12-15 wt%.

Preferably, in step 3, the specific method for preparing the PU film by using the electrospinning membrane equipment is: move the PU solution to the syringe, the spinneret needle is a flat needle with a file diameter, and the aperture is 1 mm, and the electrospinning parameters are adjusted as follows: inject The injection speed of the pump is 1.0-1.2mL/h, the receiving distance is 15-17cm, the spinning voltage is 12-15kV, the receiving roll speed is 300-350rpm, the thickness of the fiber film is regulated by controlling the spinning time, and the temperature is 100-120°C after the film is formed. Dry in the oven for 10-12 hours.

Preferably, in step 4, the fabric parameters for three-way orthogonal weaving are: 3-12K carbon fibers are selected for both the warp and weft yarns, and the linear density is 200-800tex; 3-6K carbon fibers are selected for the Z-direction yarn, and the linear density is 200-400tex; The warp density is 5-7 threads/cm, the weft density is 3-5 threads/cm, and the Z-direction density is 5-7 threads/cm; the PU-wrapped piezoelectric yarn is used as the weft yarn, and one piece is used for weaving 1cm. In this embodiment, 12K carbon fiber is selected for both the warp and weft yarns, and the linear density is 800tex; 6K carbon fiber is selected for the Z-direction yarn, and the linear density is 400tex; the warp density is 5 threads/cm, the weft density is 4 threads/cm, and the Z-direction density is 5 yarns/cm; PU-wrapped piezoelectric yarns are used as weft yarns, and one piece is used for weaving 1cm.

Step 5, impregnating the woven fabric prepared in step 4 in the epoxy resin matrix, and then curing the woven fabric impregnated with epoxy resin by vacuum assisted resin transfer molding (VARTM) technology to obtain piezoelectric yarn reinforced resin matrix composite material.

Preferably, in step 5, the epoxy resin matrix is prepared from epoxy resin and curing agent with a mass ratio of 100:85 as raw materials.

Preferably, in step 5, the curing temperature is 90-135° C., and the curing time is 9-10 hours; specifically, firstly curing at 90° C. for 2 hours, then raising the temperature to 110° C. for 1 hour, and then raising the temperature to 135° C. for 6 hours.

Test method: The composite material is subjected to a three-point bending test on a universal testing machine, and a Keithley is used to perform a piezoelectric test, and then the response relationship between the mechanical properties and the piezoelectric properties is established.

Example 1

(1) Using carbon fiber as the core layer and PVDF solution as the spinning solution, the electrospinning parallel electrode method is used to prepare piezoelectric core-spun yarns with carbon fiber as the core layer and PVDF fiber net as the cortex;

At room temperature, take 2g of PVDF powder and dissolve it in 12.6g of N,N-dimethylformamide and 5.4g of acetone solvent, and then magnetically stir at 55°C for 6h under sealed conditions. Cool to room temperature to obtain a concentration of 10wt% PVDF solution;

Fix the syringe containing the PVDF solution in the syringe pump of the electrospinning equipment, the flow rate of the spinning solution is 0.4ml/h, the spinning voltage is 5KV, the spinning distance is 8cm, the distance between the two needles is 10cm, and the winding roller The spinning speed is 0.1mm/s, the bell mouth speed is 400rpm, the spinning ambient temperature is 20±2°C, the relative humidity is 60±5%; the drying temperature is 60°C, and the drying time is 2h;

(2) The piezoelectric core-spun yarn prepared in step 1 is two-dimensionally braided by a two-dimensional braiding machine, so that the outer side is coated with carbon fiber, and the piezoelectric core-spun yarn with the outer layer made of carbon fiber, the middle layer made of PVDF fiber mesh, and the core layer made of carbon fiber is obtained. yarn;

(3) The piezoelectric yarn prepared in step 2 is completely covered with a PU film to obtain a PU-wrapped piezoelectric yarn;

Using the PU solution as the spinning solution, the PU fiber membrane was prepared by electrospinning membrane equipment; a certain amount of the PU solution was transferred to a syringe with a capacity of 10mL, and the spinneret needle was a specially made flat needle with a pore size of 1mm. Adjust the electrospinning parameters as follows: the injection speed of the syringe pump is 1.0mL/h, the receiving distance is 15cm, the spinning voltage is 15kV, the receiving roller speed is 300rpm, and the thickness of the fiber film is adjusted by controlling the spinning time; the PU film is placed in an oven at 100°C , drying for 10 hours;

At room temperature, take 15g of PU particles and dissolve them in 85g of N,N-dimethylformamide, and then magnetically stir at 55°C for 6h under sealed conditions. 15wt% PU solution;

(4) Carry out three-way orthogonal weaving with the piezoelectric yarn wrapped by PU prepared in step 3 and carbon fiber to obtain a woven fabric with carbon fiber as the main body and piezoelectric yarn wrapped by PU as the weft yarn;

The fabric parameters of three-way orthogonal weaving are: 12K carbon fiber is selected for warp and weft yarn, and its linear density is 800tex; 6K carbon fiber is selected for Z-direction yarn, and its linear density is 400tex; the warp density is 5 threads/cm, and the weft density is 4 threads/cm. The Z-direction density is 5 threads/cm; the piezoelectric yarn wrapped in PU is used as the weft yarn, and one piece is used for weaving 1cm;

(5) The woven fabric prepared in step 4 was impregnated in the epoxy resin matrix, and then the woven fabric impregnated with epoxy resin was cured by vacuum-assisted resin transfer molding technology, first cured at 90 °C for 2 hours, and then heated to 110 °C ℃ for 1 hour, and then heated up to 135 ℃ for 6 hours to obtain piezoelectric yarn-reinforced resin-based composite materials.

It can be seen from Figure 1 that PVDF is uniformly and tightly coated on the carbon fiber, and the surface is smooth. It can be seen from Figure 2 that the carbon fiber is closely combined with PVDF, and the interface is good.

It can be seen from Figure 3 that the piezoelectricity will fluctuate to varying degrees during the service of the composite material. When the piezoelectric fluctuation is large, it means that the composite material has delamination, fiber breakage, matrix cracking, etc., so that the mechanical properties of the composite material can be reflected through the piezoelectric performance, and the purpose of composite material health monitoring can be achieved.

Example 2

(3) The prepared PU film completely covers the piezoelectric yarn prepared in step 2 to obtain a PU-wrapped piezoelectric yarn;

Using the PU solution as the spinning solution, the PU fiber membrane was prepared by electrospinning membrane equipment; a certain amount of the PU solution was transferred to a syringe with a capacity of 10mL, and the spinneret needle was a specially made flat needle with a pore size of 1mm. Adjust the electrospinning parameters as follows: the injection speed of the syringe pump is 1.0mL/h, the receiving distance is 15cm, the spinning voltage is 15kV, the receiving roller speed is 300rpm, the thickness of the fiber film is regulated by controlling the spinning time; the PU film is placed in an oven at 100°C , drying for 10 hours;

At room temperature, take 14g of PU particles and dissolve them in 85g of N,N-dimethylformamide, and then stir magnetically at 55°C for 6 hours under sealed conditions. 14wt% PU solution;

Example 3

At room temperature, take 2.5g of PVDF powder and dissolve it in 12.6g of N,N-dimethylformamide and 5.4g of acetone solvent, and then magnetically stir at 55°C for 6 hours under sealed conditions. After heating, take out Leave it to stand and cool to room temperature to obtain a PVDF solution with a concentration of 12.5wt%;

Fix the syringe containing the PVDF solution in the syringe pump of the electrospinning equipment, the flow rate of the spinning solution is 0.4ml/h, the spinning voltage is 5KV, the spinning distance is 8cm, the distance between the two needles is 10cm, and the winding roller The spinning speed is 0.1mm/s, the bell mouth speed is 300rpm, the spinning ambient temperature is 20±2°C, the relative humidity is 60±5%; the drying temperature is 60°C, and the drying time is 2h;

What is not mentioned in the present invention is applicable to the prior art.

Claims

A method for preparing a piezoelectric yarn-reinforced resin-based composite material, characterized in that the method comprises the following steps:

Step 1. Using carbon fiber as the core layer and piezoelectric polymer solution as the spinning solution, the piezoelectric polymer is spun on the outer layer of the carbon fiber by the electrospinning parallel electrode method to prepare the core layer as carbon fiber and the skin layer as piezoelectric Piezoelectric core-spun yarns of polymeric webs;

Step 2. Use the piezoelectric core-spun yarn prepared in step 1 as the core yarn and carbon fiber as the braided yarn to carry out two-dimensional weaving to obtain a piezoelectric composite with carbon fiber as the outer layer, piezoelectric polymer fiber mesh as the middle layer, and carbon fiber as the core layer. yarn;

Step 3, coating the piezoelectric yarn prepared in step 2 with a PU film to obtain a PU-wrapped piezoelectric yarn;

Step 4, carrying out three-way orthogonal weaving of the PU-wrapped piezoelectric yarn and carbon fiber prepared in step 3, to obtain a woven fabric with carbon fiber as warp yarn and carbon fiber and PU-wrapped piezoelectric yarn as weft yarn;

Step 5, impregnating the woven fabric prepared in step 4 into an epoxy resin matrix, and then curing the woven fabric impregnated with epoxy resin by vacuum-assisted resin transfer molding technology to obtain a piezoelectric yarn-reinforced resin-based composite material.
The preparation method of piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, in step 1, the piezoelectric polymer is PVDF, PAN or PA11.
The method for preparing a piezoelectric yarn-reinforced resin-based composite material according to claim 1, wherein in step 1, the electrospinning parallel electrode method is specifically: fixing a syringe containing a piezoelectric polymer solution on an electrostatic In the syringe pump of the spinning equipment, adjust the electrospinning parameters, connect the spinneret to the positive and negative poles of the power supply, and the solution will be accelerated at the apex of the spinneret Taylor cone under the action of the electric field force. Next, overcome the surface tension and spray the thin stream, so that the thin stream forms a fiber network at the bell mouth; at the same time, after the carbon fiber passes through the bell mouth, it is pulled by the winding roller, so that the piezoelectric polymer fiber is evenly coated on the rotating bell mouth. carbon fiber, and collected on the winding roller to obtain the piezoelectric core-spun yarn with the carbon fiber as the core layer and the piezoelectric polymer fiber net as the skin layer, and dried in an oven;

Electrospinning parameters are: the flow rate of spinning solution is 0.4-0.6ml/h, the spinning voltage is 4.5-5kV, the spinning distance is 8-10cm, the distance between two needles is 10-12cm, and the speed of winding roller is 0.1-0.3 mm/s, the bell mouth speed is 400~450rpm, the spinning environment temperature is 20±2℃, the relative humidity of the spinning environment is 60±5%; the drying temperature is 60~100℃, and the drying time is 2~4h.
The preparation method of piezoelectric yarn reinforced resin-based composite material according to claim 1, characterized in that, in step 2, the specific operation of two-dimensional weaving is: 1) determine the number of spindles used according to the yarn structure; 2) According to the selected number of spindles, wind the corresponding number of carbon fiber bobbins; 3) Place the carbon fiber bobbin on the yarn carrier; 4) After the piezoelectric core-spun yarn obtains a certain tension through the tension device, it is fed along the axial direction of the final formed yarn 5) The carbon fiber bobbin rotates at a constant speed to realize the weaving of the two-dimensional braided core-spun yarn.
The preparation method of piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, in step 3, coating is to lay the PU film flat, put the piezoelectric yarn on one end of the PU film, and pass The piezoelectric yarn is wrapped in the PU film by winding.
The preparation method of piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, in step 3, the preparation method of PU film is: use PU solution as spinning solution, and use electrospinning equipment to prepare PU Fiber film; the receiving device is a receiving roller rotating around an axis;

The specific preparation method of the PU solution is: at room temperature, take the PU particles and dissolve them in N,N-dimethylformamide, and then stir them magnetically at 50-60°C for 6-8 hours under sealed conditions. After heating, Take it out and let it stand to cool to room temperature to obtain a PU solution with a concentration of 12-15 wt%.
The preparation method of piezoelectric yarn-reinforced resin-based composite material according to claim 6, characterized in that, the specific method of preparing PU film by using electrospinning equipment is: move the PU solution into the syringe, and the spinneret needle is a file Flat needles with an aperture of 1mm, adjust the electrospinning parameters as follows: injection pump injection speed 1.0-1.2mL/h, receiving distance 15-17cm, spinning voltage 12-15kV, receiving roller speed 300-350rpm, by controlling the spinning The thickness of the fiber film is controlled by the silk time. After the film is formed, it is dried in an oven at 100-120°C for 10-12 hours.
The preparation method of piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that in step 4, the fabric parameters of three-way orthogonal weaving are: both warp yarn and weft yarn are selected from 3-12K carbon fiber, linear density 200-800tex; choose 3-6K carbon fiber for Z-direction yarn, linear density 200-400tex; warp density 5-7 strands/cm, weft density 3-5 strands/cm, Z-direction density 5-7 strands/cm cm; PU-wrapped piezoelectric yarn is used as weft yarn, and one piece is used for weaving 1cm.
The method for preparing a piezoelectric yarn-reinforced resin-based composite material according to claim 1, wherein in step 5, the epoxy resin matrix is prepared from epoxy resin and curing agent with a mass ratio of 100:85 made.
The preparation method of piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, in step 5, the curing temperature is 90-135° C., and the curing time is 9-10 hours.