A dielectric sensor capable of identifying resin flow direction and its preparation method and application

Abstract

The present invention belongs to the technical field related to direction monitoring, and discloses a dielectric sensor capable of identifying the flow direction of resin, a preparation method thereof, and an application thereof. The dielectric sensor comprises an upper electrode and a lower electrode, wherein the shape of the lower electrode is a first conductor in a continuous pattern, and the upper electrode is located within the outer contour of the continuous pattern, which are respectively an upper region, a lower region, a left region, and a right region, wherein the four regions are respectively provided with second conductors, the number of second conductors in the upper region is different from the number of second conductors in the lower region, the number of second conductors in the left region is different from the number of second conductors in the right region, and multiple second conductors in the same region are arranged at intervals; the first wire connects the second conductors in the left region and the right region to form a first signal channel, and the second wire connects the second conductors in the upper region and the lower region to form a second signal channel. The present invention reduces the system hardware cost of resin flow direction monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field related to direction monitoring, and more specifically, relates to a dielectric sensor capable of identifying the flow direction of resin, and a preparation method and application thereof. Background Art

[0002] Fiber-reinforced resin-based composite materials have outstanding advantages such as high specific strength and high specific modulus. They are widely used in aerospace, rail transportation and other fields. Composite liquid molding process is one of the key technologies to achieve composite molding. Its efficient production and excellent performance ensure the quality and competitiveness of composite products. The wide application and flexibility of this process enable composite molding to adapt to various product requirements and play an important role in modern industry. In the composite liquid molding process, the resin flow affects the uniformity and integrity of the resin filling mold. Abnormal resin flow is prone to cause defects such as pores and dry spots, which reduces the mechanical properties of the product. At the same time, it will produce unnecessary production waste and subsequent processing steps, increasing production costs. By monitoring the resin flow direction, problems in the resin filling process can be discovered in time, and timely adjustments and improvements can be made to ensure the stability and consistency of the production process, improve the reliability and production efficiency of the process, ensure the uniformity and integrity of the resin filling mold, and ensure the quality and performance of the product. Therefore, the monitoring of the resin flow direction in the composite molding process is crucial and has great significance for controlling the molding quality of composite components.

[0003] At present, sensors that can monitor resin flow include liquid pressure sensors, optical fiber sensors, capacitive sensors, etc. Optical fiber sensors are expensive, have high monitoring costs, and are fragile during the actual molding process; liquid pressure sensors and capacitive sensors, etc., a single sensor can only monitor the time when the resin infiltrates the sensor area but cannot monitor the flow direction of the resin. It is necessary to establish a monitoring array through multiple sensors to monitor the flow direction of the resin. The installation, connection, and debugging of multiple sensors increase the complexity of the monitoring system, and more manpower and maintenance costs are required during actual use. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a dielectric sensor capable of identifying the flow direction of resin and a preparation method and application thereof, which aims to reduce the monitoring cost of resin flow.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a dielectric sensor capable of identifying the flow direction of a resin, the dielectric sensor comprising an upper electrode, a lower electrode and a composite material layer arranged between the upper electrode and the lower electrode, the lower electrode being in the shape of a continuous figure, which is an integrated first conductor, the upper electrode being located within the outer contour of the continuous figure, which are respectively an upper region, a lower region, a left region and a right region, the upper region, the lower region, the left region and the right region are respectively provided with second conductors, the number of second conductors in the upper region is different from the number of second conductors in the lower region, the number of second conductors in the left region is different from the number of second conductors in the right region, and a plurality of second conductors located in the same region are arranged at intervals;

[0006] The first conductive wire connects the second conductive body in the left region and the second conductive body in the right region to form a first signal channel, and the second conductive wire connects the second conductive body in the upper region and the second conductive body in the lower region to form a second signal channel.

[0007] Furthermore, the shape of the first conductor is the same as or different from the shape of the second conductor.

[0008] Furthermore, the shapes and sizes of the plurality of second conductors are the same or partially the same.

[0009] The present invention also provides a method for preparing a dielectric sensor capable of identifying the flow direction of a resin, wherein the method is used to prepare the dielectric sensor capable of identifying the flow direction of a resin as described above; wherein the upper electrode and the lower electrode are prepared by any one of metal foil cutting and pasting, physical vapor deposition technology, inkjet printing technology, and spraying technology.

[0010] Furthermore, the base material of the upper electrode and the lower electrode is any one of a polyimide film, a polyurethane film and a polyvinylidene fluoride film.

[0011] The present invention also provides an application of the dielectric sensor capable of identifying the resin flow direction as described above in monitoring the resin flow direction during the composite material molding process, characterized in that the dielectric sensor is pre-buried between fiber layers of the composite material to be monitored, and the capacitance signal change characteristics of the dielectric sensor are monitored to reflect the resin flow direction during the composite material molding process.

[0012] Furthermore, the directional characteristics of the capacitance change of the dielectric sensor correspond to the resin flow direction in the sensing area.

[0013] Furthermore, the signal characteristics of the first signal channel and the second signal channel are coupled to analyze the resin flow direction.

[0014] In general, compared with the prior art, the dielectric sensor capable of identifying the flow direction of resin provided by the present invention and its preparation method and application mainly have the following beneficial effects:

[0015] 1. By designing the directional characteristics of the electrodes of the dielectric sensor, the capacitance signal change of the dielectric sensor has directional characteristics associated with the resin flow direction, and the monitoring function of the dielectric sensor is diversified in the field of composite material molding monitoring; dual signal channels are used to respectively connect discontinuous electrode areas with parallel directional characteristics, and signal characteristics associated with the signal channel and the resin flow direction are established, giving a single sensor the function of monitoring the resin flow direction, promoting the engineering application of dielectric sensors in the field of composite material molding monitoring, and helping to timely discover abnormal conditions in the flow of resin inside the mold during production, avoiding problems such as uneven resin filling, pores or dry spots, and ensuring production efficiency and product quality.

[0016] 2. Using a single sensor to realize the resin flow direction monitoring function that traditional dielectric sensors require multiple sensors to establish a monitoring array to achieve greatly saves raw materials and monitoring costs, reduces the complexity of the monitoring system, makes the installation, layout and use of sensors simpler and more convenient, improves production efficiency and reduces production costs.

[0017] 3. A single dielectric sensor can monitor the resin flow direction during the composite material forming process. It is easy to use, low cost, and conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of electrodes of a dielectric sensor capable of identifying the flow direction of resin in an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of the flow direction of the resin in the glass fiber cloth with the dielectric sensor attached thereto in an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of the flow front when the resin infiltrates the left area of ​​the dielectric sensor in an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of capacitance signal output results of the first signal channel and the second signal channel when the resin infiltrates different areas of the dielectric sensor in an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of the flow front when the resin simultaneously infiltrates the upper and lower regions of the dielectric sensor in an embodiment of the present invention;

[0023] Figure 6is a schematic diagram of the flow front when the resin infiltrates the right area of ​​the dielectric sensor in an embodiment of the present invention;

[0024] Figure 7 is a schematic diagram of electrodes of a dielectric sensor in another embodiment of the present invention;

[0025] Figure 8 Resin impregnation Figure 7 Schematic diagram of the flow front in the sensing area of ​​the dielectric sensor;

[0026] Fig. 9 It is a schematic diagram of an online monitoring method for resin flow direction in a composite material molding process provided by the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] See also Figure 1 The present invention provides a dielectric sensor capable of identifying the flow direction of a resin, the dielectric sensor comprising a composite material layer, an upper electrode and a lower electrode, the composite material layer being arranged between the upper electrode and the lower electrode. The lower electrode is in the shape of a continuous figure, which is an integrated first conductor, the upper electrode is located within the outer contour of the continuous figure, which are respectively an upper region, a lower region, a left region and a right region, the upper region, the lower region, the left region and the right region are respectively provided with a second conductor, the number of the second conductors in the upper region is different from the number of the second conductors in the lower region, the number of the second conductors in the left region is different from the number of the second conductors in the right region, and a plurality of second conductors in the same region are arranged at intervals.

[0029] The second wire connects the second conductor in the upper area and the second conductor in the lower area to form a second signal channel, and the first wire connects the second conductor in the left area and the second conductor in the right area to form a first signal channel, and the first wire is perpendicular to the second wire.

[0030] The first wire and the second wire also lead out a first lead and a second lead respectively, and the dielectric sensor is connected to the signal acquisition component through the first lead and the second lead. The shape of the first conductor and the shape of the second conductor can be any one or more of geometric figures or non-geometric figures such as rectangle, circle, triangle, etc. The shape of the first conductor and the shape of the second conductor can be the same or different.

[0031] The shapes and sizes of the plurality of second conductors may all be the same, or the shapes and sizes may be partially the same. The base material of the upper electrode and the lower electrode is any one of a polyimide film, a polyurethane film and a polyvinylidene fluoride film.

[0032] The present invention also provides a method for preparing a dielectric sensor, wherein the method is used to prepare the dielectric sensor capable of identifying the flow direction of resin as described above.

[0033] See also Fig. 9 , the preparation method mainly comprises the following steps:

[0034] Step 1: Select the conductive material.

[0035] The conductive material includes one or more of metal foil, metal powder, carbon nanotube, graphene, graphene oxide or reduced graphene oxide.

[0036] Step 2: Design the shape of the lower electrode and the upper electrode of the dielectric sensor; wherein the shape of the lower electrode can be designed as a continuous pattern according to actual conditions, and the upper electrode needs to be within the outer contour of the continuous pattern presented by the lower electrode, and is divided into four regions, namely the upper region, the lower region, the left region and the right region, according to the direction recognition function. The electrodes in the upper and lower regions are designed as discontinuous patterns, and the electrode parts in the left and right regions are also set as discontinuous patterns.

[0037] Step three, using the polyurethane film as a substrate, taking the conductive material as a raw material, and forming the sensor electrodes on the polyurethane film through electrode preparation technology.

[0038] The electrode preparation technology includes any one of metal foil cutting and pasting, physical vapor deposition technology, inkjet printing technology, and spraying technology.

[0039] Step 4: After the flexible wire is connected to the surface of the electrode, the electrode is encapsulated with a polyurethane film to obtain the dielectric sensor.

[0040] The present invention also provides an application of the dielectric sensor capable of identifying the resin flow direction as described above in monitoring the resin flow direction during the composite material molding process, specifically:

[0041] S1. Pre-embed the dielectric sensor between fiber layers of the composite material to be monitored; wherein the dielectric sensor is a flexible dielectric sensor having directional electrode design features and directional signal channel features.

[0042] S2. Composite material molding is performed. During the composite material molding process, external pressure is used to make the resin liquid infiltrate between the fiber layers.

[0043] S3, monitoring the capacitance signal change characteristics of the dielectric sensor to reflect the resin flow direction during the composite material molding process, wherein the directional characteristics of the capacitance change of the dielectric sensor correspond to the resin flow direction in the sensing area.

[0044] By designing the directional characteristics of the electrodes of the dielectric sensor, the directional characteristics of the capacitance signal of the dielectric sensor associated with the resin flow direction are established. When the resin flow direction is perpendicular or parallel to the wire direction of the sensor, the single-channel signal of the sensor can identify the resin flow front from different directions, but when the angle of the resin flow direction changes, the single-channel signal is difficult to decouple; therefore, the sensor area is divided according to the rectangular coordinate system, and the discontinuous electrodes with parallel directional characteristics are connected by dual signal channels respectively, and the signal characteristics associated with the resin flow direction are established, so that the sensor can monitor the resin flow front that infiltrates the sensing area from different angles. When the resin infiltrates the sensing area from different angles, the channels with different directional characteristics will generate capacitance signals with different directional characteristics, and the changed capacitance signals are collected and stored by the signal acquisition device and transmitted to the microprocessor, and the resin flow direction is monitored according to the capacitance signal change characteristics of the dual channels. The method of the present invention uses a single sensor to realize resin flow direction monitoring, which can save production costs, reduce the complexity of the monitoring system, and improve production efficiency.

[0045] The present invention is further described in detail below with reference to several specific embodiments.

[0046] Example 1

[0047] The method for preparing the dielectric sensor provided in Embodiment 1 of the present invention comprises the following steps:

[0048] 1) Take two pieces of 50mm*50mm copper foil and cut one of them into several 5mm*5mm small rectangular pieces of copper foil for later use.

[0049] 2) Take a piece of commercial polyurethane plastic film, stick a 50mm*50mm copper foil inside the polyurethane film, and connect the wire and the copper foil with conductive silver paste to serve as the lower electrode of the sensor.

[0050] 3) Take another piece of polyurethane plastic film, divide it into an area of ​​50mm*50mm, and press a small rectangular copper foil of 5mm*5mm Figure 1 As shown, it is pasted in the polyurethane film as the upper electrode of the sensor, and conductive silver paste and a wire are used to connect the small rectangular copper foils in the left and right areas to lead out as the first signal channel. Then, conductive silver paste and a second wire are used to connect the small rectangular copper foils in the upper and lower areas to lead out as the second signal channel.

[0051] 4) Use a plastic sealing machine to plastic seal the upper and lower electrodes respectively to obtain a dielectric sensor.

[0052] The use of the prepared dielectric sensor to monitor the resin flow direction during the material molding process includes the following steps:

[0053] 5) Prepare 20 sheets of EWR200 woven glass fiber cloth (25cm*20cm) LY1564 epoxy resin A total of 375 g of 22962 curing agent was mixed evenly at a ratio of 4:1 at 40°C and defoamed after mixing.

[0054] 6) Place a 3mm transparent tempered glass plate on a horizontal table, clean the surface of the glass plate, spray a layer of release agent evenly on the surface of the glass plate, and then put the glass plate into an oven and dry it at 100℃ for 10 minutes. After the glass plate is taken out and cooled, stick the sealant on the four sides of the glass plate without tearing off the white paper on the surface of the sealant. Lay glass fiber cloth in the sealant.

[0055] In this embodiment, the lower electrode of the sensor is placed on the surface of the glass plate and the top layer of the glass fiber cloth; then a vacuum bag film is laid on the surface, and the white paper on the surface of the sealant is torn off to form a sealed space; and a vacuum pump is used to evacuate the sealed space to a vacuum state.

[0056] 7) Place the vacuum tube for resin infusion in the resin solution prepared in step 5), open the vacuum valve, and fill the resin under vacuum. The resin infiltrates the sensor monitoring area under atmospheric pressure. When the resin content in the monitoring area changes, the dielectric inside the sensor changes, thereby generating a capacitance signal change. After being transmitted to the signal acquisition device through a wire, the resin flow direction in the glass fiber composite material molding process can be monitored through the capacitance signal change characteristics of the sensor.

[0057] Among them, the capacitance signal change characteristics of the sensor are related to the directional characteristic design of the electrode. A dual-channel signal is used to connect discontinuous electrodes with parallel directional characteristics. When the resin infiltrates the sensor area from a certain direction, the capacitance signal change of the sensor presents the signal characteristics of that direction.

[0058] Take the example of resin flowing from left to right in one direction. Figure 2As shown in the figure, the sensor monitoring results and analysis are described in detail. Figure 3 and Figure 4 As shown in (a), when the resin soaks the left area of ​​the sensor, the first signal channel connecting the left and right areas shows a capacitance signal change. Since the left area electrode is two discontinuous small rectangular copper foils, the capacitance signal in this direction is characterized by a "two-stage" increase, that is, when the resin soaks the first copper foil, the capacitance signal increases significantly, when the resin soaks the wire between the first copper foil and the second copper foil, the capacitance increases slowly, and when the resin soaks the second copper foil, the capacitance signal increases significantly again.

[0059] like Figure 5 and Figure 4 As shown in (b), when the resin infiltrates the upper and lower areas of the sensor at the same time, the capacitance signal changes in the second signal channel connecting the upper and lower areas. Since the resin infiltrates the three monitoring areas of the upper and lower areas at the same time, the capacitance signal at this time increases significantly and then remains stable, without directional characteristics in the left and right directions, which also proves the necessity of using dual signal channels. At this time, since the long section of the wire area of ​​the first signal channel infiltrated by the resin is large, the capacitance of the first signal channel increases slowly. At this stage, the relative change amplitude of the signal can be reduced by optimizing the electrode design and wire area.

[0060] like Figure 6 , Figure 4 As shown in (c), when the resin infiltrates the right area of ​​the sensor, the capacitance of the first signal channel changes again. Since the electrode in the right area is a piece of copper foil, the directional characteristics of the capacitance signal in this area are "one-stage" increase. When the resin completely infiltrates the sensor area, the capacitance signals of the first signal channel and the second signal channel remain unchanged. Among them, the total capacitance change amplitude of the first signal channel and the second signal channel is similar.

[0061] Example 2

[0062] Please refer to Figure 7 The method for preparing the dielectric sensor provided in Embodiment 2 of the present invention comprises the following steps:

[0063] 1) Take two pieces of 100mm*100mm copper foil, cut one of them into several 15mm*10mm large rectangular copper foils and 5mm*5mm small rectangular copper foils for later use.

[0064] 2) Take a piece of commercial polyurethane plastic film, stick a 100mm*100mm copper foil inside the polyurethane film, and connect the wire and the copper foil with conductive silver paste to serve as the lower electrode of the sensor.

[0065] 3) Take another piece of polyurethane plastic film, divide it into an area of ​​100mm*100mm, and press the cut rectangular copper foil Figure 7As shown, it is pasted in the polyurethane film as the upper electrode of the sensor, and conductive silver paste and a wire are used to connect the small rectangular copper foils in the left and right areas to lead out as the first signal channel. Then, conductive silver paste and a second wire are used to connect the small rectangular copper foils in the upper and lower areas to lead out as the second signal channel.

[0066] 4) Use a plastic sealing machine to plastic seal the upper and lower electrodes respectively to obtain a dielectric sensor.

[0067] In this embodiment, the arrangement of rectangular electrodes of different areas enables the dielectric sensor to monitor the resin flow direction more accurately. When the resin flow direction is at a certain angle to the vertical direction, due to the reasonable arrangement of the spacing and connection angle between the large and small electrodes, the signal change caused by the size of the electrode area of ​​the resin infiltration sensor is different, so that the directional characteristics of the signal channel and the directional characteristics of the capacitance signal can be more accurately associated with the resin flow direction.

[0068] like Figure 8As shown in the figure, the red dotted line is the connection angle between the electrodes (with the vertical direction as the reference, and the clockwise angle is positive). When the resin infiltrates the sensing area at the angle shown in the figure, the signal characteristic of the first signal channel is that the capacitance signal first increases significantly in a "two-stage" manner, which is associated with the resin flow direction from left to right, and the general situation of the resin flow is determined; the signal characteristics of the second signal channel are associated with the specific angle of the flow front: when the angle is 0° to 6°, the resin flow front first infiltrates the small electrode area on the left (the signal increases slightly, hereinafter referred to as "small"), and then continuously infiltrates the three large electrode areas (the signal is superimposed three times). When the angle is 6° to 16°, the resin flow front continuously infiltrates the three large electrode areas and the small area on the left, and finally infiltrates the small electrode area on the right, and the signal characteristics are "large + large + large + small - small"; when the angle is 16° to 27°, the resin flow front first continuously infiltrates the two large electrode areas above and the small electrode area on the left, then infiltrates the large electrode area below, and finally infiltrates the small electrode area on the right, and the signal characteristics are "large + large + small - large - small"; when the angle is 16° to 27°, the resin flow front first continuously infiltrates the two large electrode areas above and the small electrode area on the left, and then infiltrates the large electrode area below, and finally infiltrates the small electrode area on the right, and the signal characteristics are "large + large + small - large - small"; When the angle is 27°~32°, the resin flow front first infiltrates the uppermost large electrode area, then continuously infiltrates the middle large electrode area and the left small electrode area, then infiltrates the lower small electrode area, and finally infiltrates the right small electrode area. The signal characteristics are "large-large+small-large-small"; when the angle is 32°~45°, the resin flow front first infiltrates the uppermost large electrode area, then the middle large electrode area, then the left small electrode area, then the lower large electrode area, and finally the right small electrode area. The signal characteristics are "large-large-small-large-small"; when the angle is When the angle is 45° to 90°, the resin flow front first infiltrates the uppermost large electrode area, then the middle large electrode area, and finally the two small electrode areas and the large electrode area at the bottom. The signal characteristics are "large-large-small+large+small"; considering the existence of the fringe electric field of the dielectric sensor, when the resin flow direction is at a critical angle (6°, 16°, 27°, 32°, 45°), the monitoring signal characteristics are based on the characteristics with more superposition of signal changes. For example, when the resin flow direction angle is 6°, the monitoring signal characteristics are based on the characteristics of "large+large+large+small-small" at 6° to 16°. Taking this as an example, when the resin flow front infiltrates the sensing area at a negative angle, the signal characteristics of 0° to -90° are opposite to the order of appearance of the signal characteristics of the above symmetrical angles. According to the signal characteristics of the second signal channel, only the resin flow front angle within ±45° can be monitored in detail. When the angle based on the second signal channel wire is greater than ±45°, the resin flow front angle based on the first signal channel is within the range of 0° to ±45°. At this time, combined with the signal characteristics of the first signal channel (the same as the second signal channel) for coupling analysis, accurate monitoring of the resin flow direction can be achieved with a single sensor.

[0069] The present invention designs the directional characteristics of the electrodes of the dielectric sensor to establish the directional characteristics that the sensor capacitance signal is associated with the resin flow direction; uses signal channels to respectively connect discontinuous electrodes with parallel directional characteristics to establish signal characteristics that the signal channel is associated with the resin flow direction, thereby realizing online monitoring of the resin flow direction in the composite material molding process by the dielectric sensor, which helps to timely discover abnormal conditions in the flow of resin inside the mold during production, and provides reliable data support for parameter control of the composite material molding process; at the same time, the sensor is cleverly designed to use a single sensor to realize the resin flow direction monitoring function that traditional dielectric sensors need to establish a monitoring array with multiple sensors, thereby reducing the complexity of the monitoring system, saving production costs, improving production efficiency, and providing effective protection for the control of the composite material molding process.

[0070] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dielectric sensor capable of identifying the flow direction of a resin, characterized in that: The dielectric sensor comprises an upper electrode, a lower electrode and a composite material layer arranged between the upper electrode and the lower electrode, the lower electrode is in the shape of a continuous pattern, which is an integrated first conductor, the upper electrode is located within the outer contour of the continuous pattern, which are respectively an upper region, a lower region, a left region and a right region, the upper region, the lower region, the left region and the right region are respectively provided with second conductors, the number of second conductors in the upper region is different from the number of second conductors in the lower region, the number of second conductors in the left region is different from the number of second conductors in the right region, and a plurality of second conductors located in the same region are arranged at intervals; The first wire connects the second conductor in the left area and the second conductor in the right area to form a first signal channel, and the second wire connects the second conductor in the upper area and the second conductor in the lower area to form a second signal channel; The first conductive line and the second conductive line are perpendicular to each other.

2. The dielectric sensor capable of identifying the resin flow direction as claimed in claim 1, characterized in that: The shape of the first conductor is the same as or different from the shape of the second conductor.

3. The dielectric sensor capable of identifying the resin flow direction according to claim 1, characterized in that: The shapes and sizes of the plurality of second conductors are all the same or partially the same.

4. A method for preparing a dielectric sensor capable of identifying the flow direction of a resin, characterized in that: The preparation method is used to prepare the dielectric sensor capable of identifying the flow direction of resin as described in any one of claims 1-3; wherein the upper electrode and the lower electrode are prepared by any one of metal foil cutting and pasting, physical vapor deposition technology, inkjet printing technology, and spraying technology.

5. The method for preparing a dielectric sensor capable of identifying the flow direction of a resin as claimed in claim 4, characterized in that: The base material of the upper electrode and the lower electrode is any one of a polyimide film, a polyurethane film and a polyvinylidene fluoride film.

6. Use of a dielectric sensor capable of identifying resin flow direction according to any one of claims 1 to 3 in monitoring resin flow direction during composite material molding, characterized in that: The dielectric sensor is pre-buried between fiber layers of the composite material to be monitored, and the capacitance signal change characteristics of the dielectric sensor are monitored to reflect the resin flow direction during the composite material molding process.

7. The use of the dielectric sensor capable of identifying the resin flow direction as claimed in claim 6 in monitoring the resin flow direction during the composite material molding process, characterized in that: The directional characteristics of the capacitance change of the dielectric sensor correspond to the resin flow direction in the sensing area.

8. The use of the dielectric sensor capable of identifying the resin flow direction as claimed in claim 6 in monitoring the resin flow direction during the composite material molding process, characterized in that: The signal characteristics of the first signal channel and the second signal channel are coupled to analyze the resin flow direction.

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