A six-electrode method for measuring the conductivity of fiber-reinforced composite materials under lightning current.

Abstract

This invention relates to a six-electrode method for measuring the conductivity of fiber-reinforced composite materials under lightning current. The apparatus includes a fixture, an excitation source, a measuring device, a silver paste layer, and copper foils, located on two opposite sides of the fiber-reinforced composite material specimen. Each copper foil has one current excitation electrode and two voltage measuring electrodes. The current excitation electrode on one copper foil is connected to the excitation source, and both voltage measuring electrodes are connected to the measuring device. The electrodes on the other copper foil are grounded. The two voltage measuring electrodes on the same copper foil are located on the same side of the current excitation electrode and are centered. Compared with existing technologies, this invention can measure the actual voltage of the specimen under excitation.

Description

Technical Field

[0001] This invention relates to the field of material property measurement, and in particular to a system and method for measuring the conductivity of fiber-reinforced composite materials under lightning current based on the six-electrode method. Background Technology

[0002] Lightning is a frequent high-intensity electromagnetic pulse discharge phenomenon in nature. Direct lightning strikes on lightning-sensitive systems such as aircraft are unavoidable. Statistics show that a single commercial airliner is struck by lightning approximately once every 10 months during its service life. Carbon fiber reinforced composites (CFRP) are lighter than traditional metal materials, helping to reduce the overall weight of aircraft, improve fuel efficiency and flight performance. At the same time, they still provide excellent strength and stiffness. These advantages make CFRP a widely used material in the aerospace industry.

[0003] Traditional metal aircraft have a significant advantage in dissipating lightning current due to the high conductivity of their materials. However, as the metal frames and skins of aircraft are gradually replaced by CFRP (fiberglass reinforced polymer), the low anisotropic conductivity of CFRP becomes a disadvantage in lightning protection. The large amount of arc heat carried by lightning strikes is directly applied to the CFRP surface. Simultaneously, due to the high resistance of CFRP, the current applied to the surface cannot be quickly dissipated, resulting in significant Joule heating. The combined effect of arc heat and Joule heating causes resin pyrolysis, carbon fiber debonding, and intense high temperatures can also cause carbon fiber vaporization and sublimation, leading to composite material failure. In numerical simulations and thermoelectric coupling models studying CFRP subjected to direct lightning strikes, conductivity significantly affects the numerical simulation and prediction of CFRP damage and temperature rise, making it a key factor in the simulation. In other words, it is necessary to improve the accuracy of the material conductivity parameters in the simulation model.

[0004] Traditional CFRP conductivity measurement methods typically employ DC excitation sources and two-electrode or four-electrode methods. However, lightning current pulses and low-amplitude DC currents differ significantly in frequency, duration, and intensity. Two-electrode measurements are susceptible to the influence of contact and wire resistance, while four-electrode measurements are affected by the distance between the electrodes, making it impossible to accurately measure the voltage at the excitation application point. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for measuring the conductivity of fiber-reinforced composite materials under lightning current based on the six-electrode method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A six-electrode method-based system for measuring the conductivity of fiber-reinforced composite materials under lightning current includes:

[0008] The device includes a clamp, an excitation source, and a measuring device, wherein the clamp is an insulating component used to hold the fiber-reinforced composite material specimen to be tested.

[0009] There are two silver paste layers, located on two opposite sides of the fiber-reinforced composite specimen to be tested.

[0010] Two copper foils are provided, located on the outside of two silver paste layers respectively, and the projection area of ​​the copper foil on its side is completely located in the projection area of ​​the corresponding silver paste layer on the same side. Each copper foil is provided with a current excitation electrode and two voltage measurement electrodes.

[0011] Among them, the current excitation electrode located on one of the copper foils is connected to the excitation source, the two voltage measurement electrodes are both connected to the measuring device, and the current excitation electrode and the two voltage measurement electrodes located on the other copper foil are both grounded;

[0012] Two voltage measuring electrodes on the same copper foil are located on the same side of the current excitation electrode, and the line connecting the current excitation electrodes on the two copper foils coincides with the axis of symmetry of the fiber-reinforced composite specimen under test. Two voltage measuring electrodes on one copper foil are paired with two voltage measuring electrodes on another copper foil, and the line connecting any voltage measuring electrode with its paired voltage measuring electrode is parallel to the axis of symmetry.

[0013] The three electrodes on the same copper foil are evenly spaced.

[0014] The area of ​​the projected region of the silver paste layer on its side overlaps with that side.

[0015] The thickness of the silver paste layer is 0.125 mm.

[0016] The distance between two adjacent electrodes on the same copper foil is:

[0017] d≥0.1b

[0018] Where: d is the distance between any two adjacent electrodes, and b is the length of the side of the copper foil along the electrode arrangement direction.

[0019] The fiber-reinforced composite material specimen to be tested is a plate with its bottom surface facing positive.

[0020] All electrodes are connected to the copper foil via lead wires.

[0021] The clamp includes:

[0022] The fixture base includes a base frame and a slide rail, a first baffle, and a hole seat disposed on the base frame. The first baffle and the hole seat are respectively disposed at both ends of the upper surface of the base frame. The slide rail is disposed in the base frame and distributed along the direction from the first baffle to the hole seat. The hole seat is provided with a first through hole.

[0023] The top pad seat includes a second baffle and a slider that cooperates with the slide rail. The second baffle is disposed on the slider and has a second through hole. The axes of the second through hole and the first through hole are on a straight line, and at least one of the second through hole and the second through hole is a screw hole. The projected area overlap rate of the second baffle and the first baffle on the vertical plane of the second through hole exceeds 90%, and it is used to clamp the fiber-reinforced composite material specimen to be tested.

[0024] A threaded rod passes through the first through hole and the second through hole respectively to connect to the second baffle to adjust the position of the second baffle along the slide direction;

[0025] Two pads, one of which is placed on the side of the first baffle closer to the second baffle, and the other pad is placed on the side of the second baffle closer to the first baffle.

[0026] The first baffle is provided with a horizontal block, which is located on the side of the second baffle away from the first baffle and is supported on the base frame.

[0027] A method based on the above measurement system includes:

[0028] Step S1: The excitation source applies excitation through the current excitation electrode;

[0029] Step S2: The measuring device obtains the voltage corresponding to the horizontal coordinate through two pairs of voltage measuring electrodes, wherein the horizontal coordinate is the coordinate relative to the electrode arrangement direction;

[0030] Step S3: Fit the voltage values ​​measured by the two pairs of voltage measuring electrodes to obtain the fitting function of the voltage value with respect to the lateral position;

[0031] Step S4: Obtain the voltage at the current-excited electrode based on the fitting function.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The six-electrode method-based conductivity measurement system for fiber-reinforced composite materials under lightning current generates lightning current excitation by using a multi-waveform, multi-pulse actual lightning current simulation test system. Combined with fiber-reinforced composite material fixtures and the six-electrode measurement method, it improves the accuracy of existing conductivity measurements of fiber-reinforced composite materials and can perform measurements under different sample sizes and different excitation source waveform parameters, providing more reliable and efficient technical support for related research and experiments.

[0034] 2. Using silver paste of sufficient size for current equalization improves the linearity of voltage variation with distance from the excitation application location, thereby improving the accuracy of the fitting.

[0035] 3. Distributing the three electrodes at equal intervals can improve the accuracy of the fitting.

[0036] 4. Setting the spacing large enough can reduce errors.

[0037] 5. Specially designed clamps can stably fix specimens of various sizes, as detailed below:

[0038] The high overlap design, with the first and second baffles having an overlap rate of over 90% in the projected areas on the vertical plane of the second through hole, ensures that the specimen is subjected to uniform pressure during clamping, avoiding deformation or damage to the specimen due to uneven pressure during measurement, thereby improving the accuracy and stability of the measurement.

[0039] An adjustable threaded rod passes through both the first and second through holes and connects to the second baffle. Adjusting the threaded rod allows for precise control of the second baffle's position along the slide rail. This design enables the fixture to accommodate specimens of different sizes, ensuring the specimen remains in the optimal position during measurement, thus improving the flexibility and applicability of the measurement process.

[0040] The cooperation between the slide and the slider allows the second baffle to move freely on the slide. This design not only facilitates the installation and removal of the specimen, but also ensures that the specimen will not shift during clamping, thereby improving the accuracy and reliability of the measurement.

[0041] Setting up the pad:

[0042] Advantages: The two pads, one on the first baffle and the other on the second baffle, effectively distribute the clamping force, preventing damage to the specimen due to excessive localized stress. Simultaneously, the pads provide additional support, ensuring the specimen remains flat during measurement and improving measurement stability.

[0043] The horizontal block is positioned on the side of the second baffle away from the first baffle and supported on the base frame. This design ensures the overall stability of the fixture and prevents tilting or shaking due to the weight of the specimen or external forces during measurement, thereby improving the accuracy and safety of the measurement.

[0044] The design of through holes and threaded holes, with the axes of the second through hole and the first through hole on a straight line, and at least one of them being a threaded hole, not only facilitates the installation and disassembly of the threaded rod, but also ensures the firmness and stability of the fixture during use, improving the reliability and durability of the measurement. Attached Figure Description

[0045] Figure 1 The A / B / C / D waveforms generated by the multi-waveform multi-pulse actual lightning current simulation test system of this invention;

[0046] Figure 2 This is a schematic diagram illustrating the principle of the present invention;

[0047] Figure 3 This is a schematic diagram showing the arrangement of the electrodes, copper foil, and silver paste of the present invention;

[0048] Figure 4 An assembly diagram of the fixture model designed for this invention;

[0049] Figure 5 Part drawings for designing the fixture model for this invention;

[0050] Figure 6 This is a schematic diagram of the structure of the clamp base of the present invention;

[0051] Figure 7 A schematic diagram of the top pad seat from one perspective;

[0052] Figure 8 This is a schematic diagram showing another perspective of the top pad seat;

[0053] Figure 9 This is a diagram showing the relationship between the potential difference on the excitation application side and the coordinates in the verification model of this invention;

[0054] Figure 10 Error curves for the six-point method and the four-point method were designed for this invention;

[0055] The components are: 1. Fixture, 2. Excitation source, 3. Measuring device, 4. Copper foil, 5. Silver paste layer, 6. Specimen, 7. Current excitation electrode, 8. Voltage measuring electrode, 1-1. Top pad seat, 1-2. Fixture base, 1-3. Pad, 1-4. Threaded rod, 1-5. Fixing sleeve, 1-6. Base fixing piece, 1-7. Thin rod, 1-8. Nut, 1-9. Fixing ball, 1-1-1. Second baffle, 1-1-2. Slider, 1-2-1. Base frame, 1-2-2. First baffle, 1-2-3. Hole seat, 1-1-1-1. Second through hole, 1-1-1-2. Nut seat, 1-2-3-1. First through hole. Detailed Implementation

[0056] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0057] The measurement system provided in this application is used to generate multi-waveform, multi-pulse actual lightning currents with different waveforms that meet the requirements of multiple international standards such as SAE, APL, and IEC, and to conduct simulation tests. It is applicable to sample plates of different sizes and shapes, can be adjusted and customized according to specific needs, uses fiber-reinforced composite material clamps that do not affect the conductivity measurement results during clamping, and employs a six-electrode measurement method that can address the influence of factors such as contact resistance, wire resistance, and inter-electrode distance on the measurement results. The specific implementation method includes the following steps:

[0058] Figure 1 The image shows the waveforms of the A / B / C / D components of lightning current generated by a multi-waveform, multi-pulse actual lightning current simulation test system that produces lightning currents of various waveforms to meet the requirements of multiple international standards such as SAE, APL, and IEC. This system generates various forms of lightning current pulses to simulate different discharge processes in real lightning events. The amplitude and occurrence order of the A / B / C / D waveforms in this system are adjustable and controllable, allowing users to freely set different parameters according to their actual needs. The output of the multi-waveform, multi-pulse actual lightning current simulation test system is connected to the current excitation electrode in the six-electrode method as excitation for subsequent measurements.

[0059] A six-electrode method for measuring the conductivity of fiber-reinforced composite materials under lightning current, such as... Figure 2 As shown, it includes:

[0060] The fixture 1, excitation source 2, and measuring device 3 are included. The fixture 1 is an insulating component used to hold the fiber-reinforced composite material specimen 6 to be tested.

[0061] There are two silver paste layers, such as layer 5. Figure 3 As shown, they are located on two opposite sides of the fiber-reinforced composite specimen 6 to be tested;

[0062] There are two copper foils 4, which are located on the outside of the two silver paste layers 5 respectively. The projection area of ​​the copper foil 4 on its side is completely located in the projection area of ​​the corresponding silver paste layer 5 on the same side. Each copper foil 4 has a current excitation electrode 7 and two voltage measurement electrodes 8.

[0063] Among them, the current excitation electrode 7 located on one of the copper foils 4 is connected to the excitation source 2, the two voltage measuring electrodes 8 are both connected to the measuring device 3, and the current excitation electrode 7 and the two voltage measuring electrodes 8 located on the other copper foil 4 are both grounded.

[0064] Two voltage measuring electrodes 8 on the same copper foil 4 are located on the same side of the current excitation electrode 7, and the line connecting the current excitation electrodes 7 on the two copper foils 4 coincides with the axis of symmetry of the fiber-reinforced composite material specimen 6 to be tested. Two voltage measuring electrodes 8 on one copper foil 4 are paired with two voltage measuring electrodes 8 on another copper foil 4, and the line connecting any voltage measuring electrode 8 with its paired voltage measuring electrode 8 is parallel to the axis of symmetry.

[0065] The six-electrode method-based conductivity measurement system for fiber-reinforced composite materials under lightning current generates lightning current excitation by using a multi-waveform, multi-pulse actual lightning current simulation test system. Combined with a fiber-reinforced composite material fixture 1 and the six-electrode measurement method, it improves the accuracy of existing conductivity measurements for fiber-reinforced composite materials and can perform measurements under different sample sizes and different excitation source waveform parameters 2, providing more reliable and efficient technical support for related research and experiments.

[0066] In this embodiment, the three electrodes on the same copper foil 4 are distributed at equal intervals, which can improve the accuracy of the fitting.

[0067] Furthermore, in this embodiment, the area of ​​the projected region of the silver paste layer 5 on its side overlaps with that side, and the flow is uniformly achieved based on the silver paste of sufficient size, thereby improving the linearity of voltage change with distance from the excitation application position, and thus improving the fitting accuracy.

[0068] In this embodiment, the thickness of the silver paste layer 5 is 0.125 mm. Of course, in other embodiments, it can be determined according to the actual situation.

[0069] Generally, the spacing between two adjacent electrodes on the same copper foil 4 is:

[0070] d≥0.1b

[0071] Where: d is the distance between any two adjacent electrodes, and b is the length of the side of the copper foil 4 along the electrode arrangement direction. Setting the distance large enough can reduce the error.

[0072] In this embodiment, the fiber-reinforced composite material specimen 6 to be tested is a plate with the bottom surface facing positive.

[0073] In actual measurements, all electrodes are connected to copper foil 4 via lead wires, which facilitates wiring.

[0074] like Figure 4 and Figure 5 As shown, fixture 1 includes:

[0075] Clamp base 1-2, such as Figure 6As shown, it includes a base frame 1-2-1 and a slide rail, a first baffle 1-2-2 and a hole seat 1-2-3 provided on the base frame 1-2-1. The first baffle 1-2-2 and the hole seat 1-2-3 are respectively provided at both ends of the upper surface of the base frame 1-2-1. The slide rail is provided in the base frame 1-2-1 and distributed along the direction from the first baffle 1-2-2 to the hole seat 1-2-3. The hole seat 1-2-3 is provided with a first through hole 1-2-3-1.

[0076] Top pad 1-3 seat 9, such as Figure 7 and Figure 8 As shown, it includes a second baffle 1-1-1 and a slider 1-1-2 that cooperates with the slide rail. The second baffle 1-1-1 is provided on the slider 1-1-2. The second baffle 1-1-1 is provided with a second through hole 1-1-1-1. The axes of the second through hole 1-1-1-1 and the first through hole 1-2-3-1 are on a straight line, and at least one of the second through hole 1-1-1-1 and the second through hole 1-1-1-1 is a screw hole. The projected area overlap rate of the second baffle 1-1-1 and the first baffle 1-2-2 on the vertical plane of the second through hole 1-1-1-1 exceeds 90%, which is used to clamp the fiber-reinforced composite material specimen 6 to be tested.

[0077] The threaded rod 1-4 passes through the first through hole 1-2-3-1 and the second through hole 1-1-1-1 respectively and connects to the second baffle 1-1-1 to adjust the position of the second baffle 1-1-1 along the slide direction;

[0078] Two pads 1-3, one of which is located on the side of the first baffle 1-2-2 near the second baffle 1-1-1, and the other pad 1-3 is located on the side of the second baffle 1-1-1 near the first baffle 1-2-2.

[0079] A horizontal block is provided on the first baffle 1-2-2. The horizontal block is located on the side of the second baffle 1-1-1 away from the first baffle 1-2-2 and is supported on the base frame 1-2-1.

[0080] The top pad 1-3 seat 9 can slide along the slide rail direction through the cooperation of the slider 1-1-2 and the slide rail, thereby adjusting the distance between the second baffle 1-1-1 and the first baffle 1-2-2. In this embodiment, a part of the second through hole 1-1-1-1 is a screw hole. Specifically, a part of the second through hole 1-1-1-1 is a round hole, and the other part forms a nut seat 1-1-1-2. A nut 1-8 is provided in the nut seat 1-1-1-2, so a part of the second through hole 1-1-1-1 is a screw hole. In addition, the threaded rod 1-4 is also provided with a thin rod 1-7 that is perpendicularly intersecting it. Fixed balls 1-9 are provided at both ends of the thin rod 1-7 for easy gripping.

[0081] The fixture 1 is suitable for sample plates of different sizes and shapes, and can be adjusted and customized according to specific needs. The main material of the fixture 1 is insulating resin, which will not affect the conductivity measurement results during the clamping process. The fixture base 1-2 and the base fixing plate 1-6 are used to fix the entire fixture 1, improving the stability of the clamping.

[0082] A method based on the above measurement system includes:

[0083] Step S1: Excitation source 2 applies excitation through current excitation electrode 7;

[0084] Step S2: The measuring device 3 obtains the voltage corresponding to the horizontal coordinate through two pairs of voltage measuring electrodes 8, wherein the horizontal coordinate is the coordinate relative to the electrode arrangement direction;

[0085] Step S3: Fit the voltage values ​​measured by the two pairs of voltage measuring electrodes 8 to obtain the fitting function of the voltage value with respect to the lateral position;

[0086] Step S4: Obtain the voltage at the current-excited electrode 7 based on the fitting function.

[0087] In this embodiment, as Figure 3 As shown, a silver paste layer 5 and a copper foil 4 are laid on the opposite side of the measurement direction of the specimen 6 to achieve a uniform distribution of current density. The copper foil can also completely cover the silver paste layer.

[0088] Below is an example of a structure with dimensions of 50×50×1mm (a×b×c) and a ply angle of [45° / -45° / 0° / 90°]. s The advantages of the six-point method are verified in the model, and the measurement process of the six-point method is introduced. A current of 2.0372E9A / m is applied to one of the current excitation electrodes 7. 2 The surface current (used to simulate a 400A current input) is used, while another current-excited electrode 7 is grounded. Figure 9 The relationship between the potential difference on the excitation application side and the coordinates is shown. It can be seen that the potential difference reaches its maximum value at the excitation application point.

[0089] When measuring resistance using the four-point method, the current measuring electrode is positioned at y = 25 mm. Due to practical limitations, it is impossible to directly measure the potential difference at the current electrode, which causes the four-point measurement results to be affected by the electrode spacing. By selecting y = 25 mm as the reference point for the potential difference, and considering that the potential difference changes almost linearly with the coordinates in its vicinity, the potential difference at y = 15 mm and y = 20 mm can be measured and used to extrapolate the potential difference at y = 25 mm. This extrapolated value is then used to calculate the impedance; this is the six-point method. Figure 10The diagram shows a comparison between the impedance error values ​​obtained using the six-point method (with one pair of current electrodes and two pairs of voltage measurement points) and those obtained using the four-point method at different coordinate points. Due to practical limitations, the voltage measurement points in the four-point resistance measurement method need to be kept at a certain distance from the current electrodes. This results in a significantly larger measurement error in the four-point method compared to the six-point method. Therefore, the six-point method is recommended for measuring the impedance of the sample.

[0090] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A system for measuring the conductivity of fiber-reinforced composite materials under lightning current based on the six-electrode method, comprising: The device includes a clamp, an excitation source, and a measuring device, wherein the clamp is an insulating component used to hold the fiber-reinforced composite material specimen to be tested. Its characteristic is that it further includes: There are two silver paste layers, located on two opposite sides of the fiber-reinforced composite specimen to be tested. Two copper foils are provided, located on the outside of two silver paste layers respectively, and the projection area of ​​the copper foil on its side is completely located in the projection area of ​​the corresponding silver paste layer on the same side. Each copper foil is provided with a current excitation electrode and two voltage measurement electrodes. Among them, the current excitation electrode located on one of the copper foils is connected to the excitation source, the two voltage measurement electrodes are both connected to the measuring device, and the current excitation electrode and the two voltage measurement electrodes located on the other copper foil are both grounded; Two voltage measuring electrodes on the same copper foil are located on the same side of the current excitation electrode, and the line connecting the current excitation electrodes on the two copper foils coincides with the axis of symmetry of the fiber-reinforced composite specimen under test. Two voltage measuring electrodes on one copper foil are paired with two voltage measuring electrodes on another copper foil, and the line connecting any voltage measuring electrode with its paired voltage measuring electrode is parallel to the axis of symmetry.

2. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, The three electrodes on the same copper foil are evenly spaced.

3. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, The area of ​​the projected region of the silver paste layer on its side overlaps with that side.

4. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, The thickness of the silver paste layer is 0.125 mm.

5. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, The distance between two adjacent electrodes on the same copper foil is: d≥0.1b Where: d is the distance between any two adjacent electrodes, and b is the length of the side of the copper foil along the electrode arrangement direction.

6. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, The fiber-reinforced composite material specimen to be tested is a plate with its bottom surface facing positive.

7. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, All electrodes are connected to the copper foil via lead wires.

8. The conductivity measurement system for fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 1, characterized in that, The clamp includes: The fixture base includes a base frame and a slide rail, a first baffle, and a hole seat disposed on the base frame. The first baffle and the hole seat are respectively disposed at both ends of the upper surface of the base frame. The slide rail is disposed in the base frame and distributed along the direction from the first baffle to the hole seat. The hole seat is provided with a first through hole. The top pad seat includes a second baffle and a slider that cooperates with the slide rail. The second baffle is disposed on the slider and has a second through hole. The axes of the second through hole and the first through hole are on a straight line, and at least one of the second through hole and the second through hole is a screw hole. The projected area overlap rate of the second baffle and the first baffle on the vertical plane of the second through hole exceeds 90%, and it is used to clamp the fiber-reinforced composite material specimen to be tested. A threaded rod passes through the first through hole and the second through hole respectively to connect to the second baffle to adjust the position of the second baffle along the slide direction; Two pads, one of which is placed on the side of the first baffle closer to the second baffle, and the other pad is placed on the side of the second baffle closer to the first baffle.

9. A system for measuring the conductivity of fiber-reinforced composite materials under lightning current based on the six-electrode method according to claim 8, characterized in that, The first baffle is provided with a horizontal block, which is located on the side of the second baffle away from the first baffle and is supported on the base frame.

10. A method based on the measurement system according to any one of claims 1-9, characterized in that, include: Step S1: The excitation source applies excitation through the current excitation electrode; Step S2: The measuring device obtains the voltage corresponding to the horizontal coordinate through two pairs of voltage measuring electrodes, wherein the horizontal coordinate is the coordinate relative to the electrode arrangement direction; Step S3: Fit the voltage values ​​measured by the two pairs of voltage measuring electrodes to obtain the fitting function of the voltage value with respect to the lateral position; Step S4: Obtain the voltage at the current-excited electrode based on the fitting function.

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