Lightning stroke multi-dimensional impact force test system for carbon fiber composite material laminated plate and analysis method for action time sequence of multi-dimensional impact force

Abstract

The invention discloses a carbon fiber composite material laminated plate lightning stroke multi-dimensional impact force test system and a multi-dimensional impact force action time sequence analysis method. The test system comprises a lightning current source with controllable source impedance and intensity, a tested metal plate, a carbon fiber composite material laminated plate, a lightning stroke multi-dimensional impact force measurement unit and a computer control and measurement data management unit, and analyzes the effect of the lightning current source with controllable source impedance and intensity on a tested object in different injection modes of lightning current. Multi-dimensional lightning impact force waveform characteristics are analyzed, and the time sequence superposition relation of lightning electromagnetic force, impact waves generated by surface explosion and acoustic impact waves generated by arc channel expansion in the acting process of lightning stroke and a tested object on the spatial-temporal scale is obtained through analysis; the internal relation between the surface structure states of the tested metal plate and the carbon fiber composite material laminated plate is determined; and a theoretical basis and a test data support are laid for a lightning stroke impact force damage mechanism of the carbon fiber composite material laminated plate and a composite material lightning protection structure design.

Description

Technical Field

[0001] This invention belongs to the field of materials testing technology, and relates to the measurement technology of the mechanical effect of lightning strikes on composite laminates. Specifically, it relates to a multi-dimensional impact force testing system for carbon fiber composite laminates under lightning strikes and an analysis method for the timing of multi-dimensional impact force action. Background Technology

[0002] Carbon fiber composites possess properties such as low density, high strength, high modulus, high temperature resistance, and chemical corrosion resistance, making them widely used in aerospace, military, and civilian industries. The use of carbon fiber composites in aircraft structures has also increased significantly; for example, the Airbus A350 and Boeing 787 use over 50% carbon fiber. The amount of composite materials used has become one of the important indicators for evaluating the advancement of aircraft. High-intensity lightning strikes can cause severe damage to carbon fiber composites, including matrix pyrolysis, fiber breakage, and deep delamination. Therefore, lightning damage to carbon fiber composites and lightning protection have become technical challenges restricting the use of carbon fiber.

[0003] The lightning strike process is a complex transient physical process involving the powerful impact force of lightning current, electromagnetic force, and thermal effects from multiple physical fields. The lightning impact force includes the surface explosion impact force caused by the lightning arc and the acoustic shock wave generated by the expansion of the arc channel. Current research focuses on the temperature rise caused by the lightning thermal effect, as well as the damage from fiber ablation and sublimation, and resin pyrolysis. Furthermore, damage simulation calculations for carbon fiber composites are primarily based on thermoelectric coupling models. These simulations only explain the damage caused by the Joule heating effect of lightning, and cannot adequately explain the delamination damage caused by the multidimensional impact force of electromagnetic force from the lightning current, the surface explosion impact force of the composite material, and the acoustic shock wave from the lightning arc. Therefore, they cannot accurately and completely characterize the damage effect of lightning on composite materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a multi-dimensional impact force testing system for carbon fiber composite laminates under lightning strikes and an analysis method for the timing of multi-dimensional impact force action. This provides a theoretical foundation and experimental data support for the quantitative analysis of the lightning damage mechanism of multi-dimensional impact forces on composite laminates and the design of lightning protection structures for composite materials.

[0005] This invention is achieved through the following technical solution:

[0006] A multi-dimensional impact force testing system for carbon fiber composite laminates by lightning strikes includes a lightning current source with controllable source impedance and intensity, a test specimen, a multi-dimensional impact force measurement unit for lightning strikes, and a computer control and data management unit.

[0007] The controllable source impedance and intensity lightning current source comprises three parts: an adjustable high-voltage DC charging power supply, an adjustable source impedance lightning current generating unit, and a charging voltage monitoring sensor. It is used to generate lightning current waves with adjustable source impedance and intensity. The test specimen is a plate-shaped metal plate or a carbon fiber composite laminate. During the test, the test specimen is connected to the circuit of the adjustable source impedance lightning current generating unit. The lightning current is injected from the center of the test specimen and flows back from two opposite end faces or four end faces of the test specimen.

[0008] The multi-dimensional lightning impact force measurement unit includes a multi-dimensional lightning impact force sensing and measuring mechanism, a recording device, and an industrial control computer. The multi-dimensional lightning impact force sensing and measuring mechanism is installed on the lower surface of the test sample. The piezoelectric signal output of the test is connected to the recording device. The recording device transmits the collected and recorded lightning current and piezoelectric signals to the industrial control computer for analysis, processing, and result output of the lightning current signal and lightning impact force signal.

[0009] The computer control and data management unit monitors and controls the generation circuit, discharge voltage, and workflow of the lightning current source with controllable source impedance and intensity.

[0010] Preferably, the adjustable high-voltage DC charging power supply includes a voltage regulator T1, a transformer T2, a current-limiting resistor Rc, and a rectifier silicon stack D; the adjustable source impedance lightning current generating unit consists of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L, and a resistor R connected in series to form a circuit, with the test sample and its clamping fixture connected in series in the circuit; the output current amplitude of the adjustable source impedance lightning current generating unit is controlled by the charging voltage of the adjustable high-voltage DC charging power supply.

[0011] Preferably, the energy storage capacitors in the adjustable source impedance lightning current generating unit are multiple capacitors C1, C2, and C3, which can be operated independently or in parallel through high-voltage switches K11, K12, and K13; similarly, the tuning inductors L1, L2, and L3 and the tuning resistors R1, R2, and R3 can be operated independently or in parallel through selection switches K21, K22, and K23, thus realizing the adjustment of the source impedance of the adjustable source impedance lightning current generating unit.

[0012] Preferably, the selection of the series branches of capacitors C1, C2, C3, as well as the tuning inductors L1, L2, L3 and tuning resistors R1, R2, R3, is automatically adjusted. The test sample is connected in series in the adjustable source impedance lightning current generating unit, and a pulse current sensor is connected to the low-voltage output bus of the adjustable source impedance lightning current generating unit of the test sample and the controllable source impedance and intensity lightning current source.

[0013] Preferably, the multidimensional lightning impact force sensing and measurement mechanism comprises a lightning impact force transmission mechanism, an impact force piezoelectric sensor, and a shielding mechanism. The piezoelectric signal output from the impact force piezoelectric sensor is connected to a recording device, which is an oscilloscope or a data acquisition system.

[0014] The multidimensional lightning strike force sensing and measurement mechanism specifically includes a pulse current sensor and a lightning current measurement oscilloscope, a multidimensional lightning strike force transmission and measurement sensor group, and a first impact force measurement oscilloscope and a second impact force measurement oscilloscope;

[0015] The lightning current measurement oscilloscope receives and detects the lightning current signal of the controlled source impedance and intensity of the lightning current source acting on the test object, extracted by the pulse current sensor; the lightning current measurement oscilloscope and the multi-dimensional lightning impact force transmission and measurement sensor group detect the lightning impact force of the test object in multiple dimensions, and analyze the lightning current and lightning impact force signals to obtain the intrinsic correlation between the multi-dimensional lightning impact force and the lightning current electrical parameters borne by the test object.

[0016] Preferably, the multidimensional lightning impact force transmission and measurement sensor group is installed on the lower surface of the test specimen, including a lightning impact force transmission mechanism, a mounting base plate located at the center of the lower surface of the test specimen, and a 45° angle at a certain distance from the center. 0 Angle, -45 0 Angle and 180 0 A multi-dimensional lightning impact piezoelectric sensor group and a shielding mechanism are set at four angles; the piezoelectric signal output measured by the multi-dimensional lightning impact piezoelectric sensor group is connected to the first impact force measuring oscilloscope and the second impact force measuring oscilloscope or a data acquisition system; the lightning current measuring oscilloscope and the first and second impact force measuring oscilloscopes then transmit the collected and recorded lightning current and multi-dimensional lightning impact piezoelectric signals to the industrial control computer respectively.

[0017] Preferably, the multidimensional lightning impact force transmission and measurement sensor group is mounted on a support base plate, and two parallel sample clamps are installed on the support base plate at a certain distance. The test sample is fixed and clamped by the metal support strips / blocks and crimping strips / blocks of the two sample clamps through fastening bolts. The horizontal ends of the test sample are respectively connected to the low-voltage output port of a lightning current source with controllable source impedance and intensity through the respective metal support strips / blocks of the sample clamps. The high-voltage output terminal of the adjustable source impedance lightning current generating unit is injected through a high-voltage injection electrode set above the center of the test sample. The distance between the high-voltage injection electrode and the center point of the upper surface of the test sample can be adjusted.

[0018] An analysis method for the timing of multidimensional lightning impact force on carbon fiber composite laminates is proposed. By adjusting the source impedance and intensity of the lightning current source, lightning current is injected into the center of the test sample through conduction or lightning arc injection. Metal plates and carbon fiber composite laminates are selected as test samples respectively. The analysis is based on the transmission of multidimensional lightning impact force on the lower surface of the test sample and the piezoelectric signal measured by the multidimensional lightning impact force piezoelectric sensor group in the sensor group.

[0019] This study analyzes the temporal relationship between the electromagnetic force of lightning and the explosive impact force on the surface of the test specimen in the multidimensional impact force obtained under the lightning conduction and injection current method. It also analyzes the difference in the lightning impact force of the lightning current on the metal plate and the carbon fiber composite laminate under the lightning conduction and injection current method, and obtains the intrinsic relationship between the shock wave generated by the explosion on the surface of the test specimen, the amplitude parameter of the lightning current, and the surface structural state of the test metal plate and the carbon fiber composite laminate.

[0020] This study analyzes the temporal superposition relationship of electromagnetic force, shock wave generated by surface explosion, and acoustic shock wave generated by arc channel expansion during the interaction between lightning strike and test object under the lightning arc injection current mode. It also analyzes the difference in lightning impact force between the lightning current and metal plate and carbon fiber composite laminate under the lightning arc injection mode, and obtains the intrinsic relationship between electromagnetic force, shock wave generated by surface explosion, acoustic shock wave generated by arc channel expansion, different source impedance or lightning current amplitude parameters, arc injection gap distance, and surface structure state of the tested metal plate and carbon fiber composite laminate.

[0021] Preferably, the specific process for analyzing the temporal relationship of the multidimensional impact force of lightning in the spatiotemporal superposition under the lightning conduction and injection current mode is as follows:

[0022] (1) Electrically connect the lightning current source with controllable source impedance and intensity, the test sample, the multi-dimensional impact force measurement unit of lightning strike and the computer control and data management unit;

[0023] (2) Metal plates and carbon fiber composite laminates were selected as test samples respectively, and the lightning current source was injected into the center point of the test sample by direct electrical contact.

[0024] (3) Select a lightning current source with controllable source impedance and intensity. The output current intensity of the lightning current source has at least 5 current levels. The programmable controller 41-2 of the lightning multidimensional impact force test control unit controls the charging voltage of the adjustable high voltage DC charging power supply to control the output current intensity of the adjustable source impedance lightning current generating unit, so that the lightning impact current flowing through the test sample reaches different amplitudes.

[0025] (4) The computer control and data management unit receives the lightning current signal measured by the pulse current sensor from the lightning current measurement oscilloscope, as well as the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group of lightning strikes at the following angles: directly below the lightning strike center point on the lower surface of the test sample, at 45°, -45° and 180°, as measured by the first impact force measurement oscilloscope and the second impact force measurement oscilloscope.

[0026] (5) The computer control and data management unit processes the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group of the lightning strike, analyzes the differences in the waveform of the piezoelectric signal obtained by the multi-dimensional impact force piezoelectric sensor group of the test sample under different source impedance lightning currents, obtains the waveform characteristics of the multi-dimensional lightning impact force waveform, the piezoelectric signal of the 0° center piezoelectric sensor on the lower surface of the test sample, the intrinsic correlation between the lightning current wind peak parameter and the thermoelectric state of the test sample surface, and analyzes the temporal superposition relationship of the electromagnetic force and the shock wave generated by the surface explosion during the interaction between the lightning strike and the test sample.

[0027] (6) Analyze the difference in lightning impact force on metal plates and carbon fiber composite laminates under the lightning conduction injection mode, and obtain the intrinsic relationship between the shock wave generated by the explosion on the surface of the test sample and the amplitude parameters of the lightning current, as well as the surface structural state of the test metal plate and carbon fiber composite laminate.

[0028] Preferably, the specific process for analyzing the temporal relationship of the multidimensional impact force of lightning in the spatiotemporal superposition under the lightning current injection mode of lightning arc is as follows:

[0029] (1) Electrically connect the lightning current source with controllable source impedance and intensity, the test sample, the multi-dimensional impact force measurement unit of lightning strike and the computer control and data management unit;

[0030] (2) Metal plates and carbon fiber composite laminates were selected as test samples respectively, and the lightning current source was injected into the center point of the test sample by direct electric arc or action gap method.

[0031] (3) Select the source impedance of the lightning current source with controllable source impedance and intensity, wherein the source impedance has at least 3 resistance values. The source impedance of the lightning current source is controlled by the lightning multidimensional impact force test control unit, and the discharge voltage of the adjustable source impedance lightning current generating unit is controlled by controlling the charging voltage of the adjustable high voltage DC charging power supply, so as to ensure reliable discharge under different arc injection gaps.

[0032] (4) Under the condition of setting the discharge voltage, the multidimensional lightning impact force of the lightning discharge circuit is tested by selecting different arc gaps and different source impedances.

[0033] (5) The industrial control computer receives the lightning current signal measured by the pulse current sensor from the lightning current measurement oscilloscope, and the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group of lightning strikes at the following angles: directly below the lightning strike center point on the lower surface of the test sample, at 45°, -45° and 180°, as measured by the first impact force measurement oscilloscope and the second impact force measurement oscilloscope.

[0034] (6) The industrial control computer processes the piezoelectric signal output by the multi-dimensional impact force piezoelectric sensor group of the lightning strike, analyzes the waveform differences of the piezoelectric signal obtained by the multi-dimensional impact force piezoelectric sensor group of the lightning strike under different source impedance lightning currents, obtains the waveform characteristics of the multi-dimensional lightning impact force waveform, especially the piezoelectric signal of the 0° piezoelectric sensor at the center of the lower surface of the test object, during the lightning strike, and the intrinsic correlation between the action gap distance of the electric arc injection, different source impedances or lightning current amplitude parameters, and the thermoelectric state of the test object surface, and analyzes the temporal superposition relationship of the electromagnetic force, the shock wave generated by the surface explosion and the acoustic shock wave generated by the expansion of the electric arc channel during the interaction between the lightning strike and the test object.

[0035] (7) Analyze the differences in the lightning impact force of lightning current on metal plates and carbon fiber composite laminates under the lightning arc gap injection mode, and obtain the intrinsic relationship between electromagnetic force, shock wave generated by surface explosion, acoustic shock wave generated by arc channel expansion, different source impedance or lightning current amplitude parameters, arc injection gap distance, and surface structure state of the tested metal plates and carbon fiber composite laminates.

[0036] The present invention has the following beneficial effects:

[0037] This invention establishes a multi-dimensional impact force testing system for carbon fiber composite laminates subjected to lightning strikes. The system includes a lightning current source with controllable source impedance and intensity, a test metal plate and a carbon fiber composite laminate, a multi-dimensional impact force measurement unit, and a computer control and measurement data management unit. The system operates at a distance of 45 degrees directly below the lower surface of the test specimen. 0 Angle below, -45 0 Angle below and 180 0 A lightning strike force measurement device is positioned below the angle. This device includes four sets of lightning strike force transmission mechanisms and piezoelectric sensors. The measurement results from the four piezoelectric sensors are output to the measurement device via a double-shielded coaxial measurement cable. The multidimensional lightning strike force waveform characteristics are analyzed by examining the effect of a lightning current source with controllable source impedance and intensity on the test sample under different lightning injection methods.

[0038] This paper proposes an analytical method for the multidimensional lightning impact force timing during lightning strikes. Under different lightning current injection methods, the method analyzes the effect of a lightning current source with controllable source impedance and intensity on the test specimen, identifying the waveform characteristics of the multidimensional lightning impact force. The method elucidates the temporal superposition relationship of the lightning electromagnetic force, the shock wave generated by the surface explosion, and the acoustic shock wave generated by the arc channel expansion during the interaction between the lightning strike and the test specimen. It also analyzes the differences in the lightning impact force exerted by the lightning current on metal plates and carbon fiber composite laminates under different lightning current modes, revealing the intrinsic relationships between the electromagnetic force, the shock wave generated by the surface explosion, the acoustic shock wave generated by the arc channel expansion, and different source impedances (or lightning current amplitude parameters), the arc injection gap distance, and the surface structural state of the tested metal plates and carbon fiber composite laminates. This provides a theoretical foundation and experimental data support for the lightning impact force damage mechanism of carbon fiber composite laminates and the design of composite lightning protection structures. Attached Figure Description

[0039] Figure 1 This is a block diagram of the multi-dimensional impact force testing system for carbon fiber composite laminates subjected to lightning strikes according to the present invention.

[0040] Figure 2 This is a schematic diagram of the lightning current source circuit with controllable source impedance and intensity in this invention;

[0041] Figure 3 This is a schematic diagram of the impact force transmission and measurement mechanism in this invention;

[0042] Figure 4a This is a schematic diagram of the test specimen installation structure in the lightning conduction injection lightning current method of the present invention;

[0043] Figure 4b This is a schematic diagram of the test specimen installation structure in the present invention, which describes the method of injecting lightning current through a lightning arc or gap.

[0044] Figure 5 This is a flowchart of the method for analyzing the timing of multidimensional lightning impact on carbon fiber composite laminates according to the present invention;

[0045] In the diagram: 1- A lightning current source with controllable source impedance and intensity; 2- The test sample; 2-1- A metal plate; 2-2- A carbon fiber composite laminate; 3- A multi-dimensional lightning impact force measurement unit; 4- A computer control and data management unit; 1-1- An adjustable high-voltage DC charging power supply; 1-2- An adjustable source impedance lightning current generating unit; 1-3- A charging voltage monitoring sensor; 31-1- A pulse current sensor; 31-2- A lightning current measurement oscilloscope; 32-1- Multi-dimensional lightning impact force transmission. And the sensor group for measuring; 32-21-First impact force measuring oscilloscope; 32-22-Second impact force measuring oscilloscope; 41-Control unit; 41-1-Charging voltage detection circuit; 41-2-Programmable controller; 42-Management unit; 4-2-Computer data analysis and management unit; S32-11-0° piezoelectric sensor; S32-12-45° piezoelectric sensor; S32-13-45° piezoelectric sensor; S32-14-180° piezoelectric sensor;

[0046] a-Lightning impact force transmission mechanism, b-Shielding mechanism, c-High voltage injection electrode, d-High voltage return electrode, e-Crimping strip / block, f-Metal support strip / block, g-Sensor output line, h-Insulating support block, i-Support base plate, j-Sample clamp, k-Mounting base plate. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0048] See Figure 1 The present invention relates to a multi-dimensional impact force testing system for carbon fiber composite laminates subjected to lightning strikes, comprising a lightning current source 1 with controllable source impedance and intensity, a test sample 2, a multi-dimensional impact force measurement unit 3 subjected to lightning strikes, and a computer control and data management unit 4.

[0049] See Figure 1 The function of the controllable source impedance and intensity lightning current source 1 is to generate lightning current waves with adjustable source impedance and intensity. It mainly consists of three parts: an adjustable high-voltage DC charging power supply 1-1, an adjustable source impedance lightning current generating unit 1-2, and a charging voltage monitoring sensor 1-3. The test sample 2 is a plate-shaped sample, which can be a metal plate such as aluminum or aluminum alloy, or a carbon fiber composite laminate with different layup and weave structures. During the test, the test sample is connected to the circuit of the adjustable source impedance lightning current generating unit 1-2. The lightning current is injected from the center and flows back from two opposite end faces or four end faces.

[0050] See Figure 1The multi-dimensional lightning impact force measurement unit 3 includes a multi-dimensional lightning impact force sensing and measurement mechanism, a recording device, and an industrial control computer. The multi-dimensional lightning impact force sensing and measurement mechanism is installed on the lower surface of the test sample and mainly consists of a lightning impact force transmission mechanism, an impact force piezoelectric sensor, and a shielding mechanism. In the multi-dimensional lightning impact force sensing and measurement mechanism, the piezoelectric signal output from the impact force piezoelectric sensor is connected to the recording device, which employs an oscilloscope or a data acquisition system. Specifically, it includes a pulse current sensor 31-1 and a lightning current measurement oscilloscope 31-2, a multi-dimensional lightning impact force transmission and measurement sensor group 32-1, and a first impact force measurement oscilloscope 32-21 and a second impact force measurement oscilloscope 32-22.

[0051] See Figure 1 The computer control and data management unit 4 includes a control unit 41 consisting of a charging voltage detection circuit 41-1 and a programmable controller 41-2, and a multi-dimensional lightning impact force data management unit 42 consisting of a computer data analysis and management unit 4-2 consisting of a computer and dedicated software.

[0052] The computer control and data management unit 4 monitors and controls the generation circuit, discharge voltage, and working process of the controllable source impedance and intensity lightning current source 1 through the charging voltage detection circuit 41-1, the programmable controller 41-2, and the computer data analysis and management unit 4-2. The lightning current measurement oscilloscope 31-2 receives and detects the lightning current signal of the controllable source impedance and intensity lightning current source 1 acting on the test object 2 extracted by the pulse current sensor 31-1. The lightning current measurement oscilloscope 31-2 and the multi-dimensional lightning impact force transmission and measurement sensor group 32-1 detect the lightning impact force of the test object 2 in multiple dimensions, and analyze the lightning current and lightning impact force signals to obtain the intrinsic correlation between the multi-dimensional lightning impact force and the lightning current electrical parameters borne by the test object 2.

[0053] See Figure 2 The adjustable high-voltage DC charging power supply 1-1 of the controllable source impedance and intensity lightning current source 1 mainly consists of a voltage regulator T1, a transformer T2, a current-limiting resistor Rc, and a rectifier silicon stack D. The adjustable source impedance lightning current generating unit 1-2 is a circuit composed of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L, and a resistor R connected in series. The test sample and its clamping fixture are connected in series in the circuit. The output current amplitude of the adjustable source impedance lightning current generating unit 1-2 can be controlled by adjusting the charging voltage of the adjustable high-voltage DC charging power supply 1-1.

[0054] To achieve source impedance adjustment in the discharge circuit, the energy storage capacitors in the adjustable source impedance lightning current generating unit 1-2 are designed as multiple capacitors C1, C2, and C3 connected to high-voltage switches K11, K12, and K13, allowing C1, C2, and C3 to operate independently or in parallel. Similarly, the tuning inductors L1, L2, and L3, and the tuning resistors R1, R2, and R3 are designed to operate independently or in parallel via selection switches K21, K22, and K23, thus enabling the adjustment of the source impedance of the adjustable source impedance lightning current generating unit 1-2. The selection of the series branches of capacitors C1, C2, and C3, as well as the tuning inductors L1, L2, and L3 and the tuning resistors R1, R2, and R3, is automatically adjusted. The test sample is connected in series in the adjustable source impedance lightning current generating unit 1-2, and a pulse current sensor 31-1 is connected to the low voltage output connection bus of the adjustable source impedance lightning current generating unit 1-2 of the lightning current source 1 with controllable source impedance and intensity.

[0055] See Figure 1 , Figure 2 The pulse current sensor 31-1 is connected to the low-voltage output bus of the adjustable source impedance lightning current generating unit 1-2 of the lightning current source 1 with controllable source impedance and intensity, and the test sample 2 is connected to the test sample 2. The measurement result of the pulse current sensor 31-1 is output to the input terminal of the lightning current measuring oscilloscope 31-2 through the double-shielded coaxial measurement cable; directly below the lightning strike center point, at 45 degrees... 0 Angle, -45 0 Angle and 180 0 The measurement results from the multi-dimensional impact force piezoelectric sensor group S32-11 to S32-14 of the lightning strike are output to the input terminals of the four-channel first impact force measurement oscilloscope 32-21 and the second impact force measurement oscilloscope 32-22 via a double-shielded coaxial measurement cable. The lightning current measurement oscilloscope 31-2 and the four-channel first impact force measurement oscilloscope 32-21 and the second impact force measurement oscilloscope 32-22 then transmit the collected and recorded lightning current and multi-dimensional lightning impact force piezoelectric signals to the industrial control computer.

[0056] See Figure 3 The multidimensional lightning impact force transmission and measurement sensor group 32-1 is installed on the lower surface of the test sample 2. It mainly consists of a lightning impact force transmission mechanism a, impact force piezoelectric sensor groups S32-11 to S32-14, a mounting base plate k, and a shielding mechanism b. The piezoelectric signal output measured by the multidimensional piezoelectric sensor group in the multidimensional lightning impact force transmission and measurement sensor group 32-1 is connected to the first impact force measurement oscilloscope 32-21 and the second impact force measurement oscilloscope 32-22 or a data acquisition system.

[0057] like Figure 4a and Figure 4bAs shown, the multi-dimensional lightning impact force transmission and measurement sensor group 32-1 is installed on the support base plate i. Two parallel sample clamps j are installed on the support base plate i at a certain distance. The sample clamps j are arranged from bottom to top as follows: an insulating support block h, a metal support strip / block f, and a crimping strip / block e. The test sample 2 is fixed and clamped by the metal support strip / block f and the crimping strip / block e of the two sample clamps by fastening bolts. The center of the lower surface of the test sample 2 and a 45° angle at a certain distance from the center are also included. 0 Angle, -45 0 Angle and 180 0 The test sample 2 is equipped with shielded piezoelectric sensors S32-11 to S32-14, which are equipped with stress wave transmission systems, at four angular positions. The horizontal ends of the test sample 2 are connected to the low-voltage output port of the lightning current source 1 with controllable source impedance and intensity through their respective metal support bars / blocks f of the test sample fixture. The high-voltage output terminal of the adjustable source impedance lightning current generating unit 1-2 is injected through a metal rod-shaped high-voltage injection electrode c located above the center of the test sample 2. The distance between the high-voltage injection electrode c and the center point of the upper surface of the test sample 2 can be adjusted. In the case of conductive injection, the injection electrode and the center point of the test sample 2 are in direct electrical contact.

[0058] like Figure 3 As shown, the shielded multidimensional lightning impact force transmission and measurement sensor group 32-1 includes a lightning impact force transmission mechanism a comprising a transmission unit, a support unit, and an absorbing unit. The top surface of the transmission unit is in close contact with the center of the lower surface of the test sample 2 and passes through the shielding mechanism b. The lower surface of the transmission unit is in contact with the upper surface of the support unit, which is made of the same material and of the same size. The lower end of the support unit is fixed to the absorbing unit. A piezoelectric sensor is installed between the lower surface of the transmission unit and the upper surface of the support unit. Two sensor output lines are electrically connected to the upper and lower electrodes of the piezoelectric sensor, respectively. The shock wave generated by lightning acting on the test sample 2 is transmitted through the transmission unit in the lightning impact force transmission mechanism a to form a uniformly distributed stress wave, which squeezes the piezoelectric sensor. A piezoelectric signal is output between the upper and lower electrodes of the piezoelectric sensor and transmitted through the sensor output lines to the first impact force measurement oscilloscope 32-21 and the second impact force measurement oscilloscope 32-22.

[0059] The measurement results from the four wire sensors of the multi-dimensional impact force sensing device for lightning strikes are output to a recording device via a double-shielded coaxial measurement cable. The recording device can be an oscilloscope or a data acquisition system; the recording device includes three oscilloscopes or three data acquisition cards. One set is used to receive the lightning current signal output from the controllable source impedance and intensity lightning current source 1 extracted by the pulse current sensor 31-1. The other two oscilloscopes are used to measure the lightning strike current signal at a distance of 45 degrees directly below the center point of the lightning strike. 0 Angle, -45 0 Angle and 180 0The piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group S32-11 to S32-14 of the angled lightning strike are recorded by an oscilloscope. The oscilloscope of the recording device transmits the collected and recorded lightning current and piezoelectric signals to the industrial control computer for analysis, processing and output of the lightning current and lightning impact force signals.

[0060] See Figure 5 In the multidimensional impact force of lightning strikes, the temporal relationship of the spatiotemporal superposition of the electromagnetic force of lightning and the explosive impact force on the surface of the test object is obtained by adjusting the source impedance and intensity of the lightning current source, injecting lightning current into the center of the test object without gaps (or conduction), and analyzing the piezoelectric signals measured by the multidimensional piezoelectric sensor group in the multidimensional impact force measurement unit of lightning strikes on the lower surface of the test object.

[0061] The specific process is as follows:

[0062] (1) Electrically connect the lightning current source 1 with controllable source impedance and intensity, the test sample 2, the lightning multi-dimensional impact force measurement unit 3, and the computer control and data management unit 4.

[0063] (2) Metal plate and carbon fiber composite laminate were selected as test specimens 2 respectively, and the lightning current source was injected into the center point of test specimen 2 by direct electrical contact.

[0064] (3) Select a lightning current source 1 with controllable source impedance and intensity, and the output current intensity should have at least 5 current levels. The programmable controller 41-2 of the lightning multidimensional impact force test control unit controls the charging voltage of the adjustable high voltage DC charging power supply 1-1 to control the output current intensity of the adjustable source impedance lightning current generating unit 1-2, so that the lightning impact current flowing through the test object 2 reaches different amplitudes.

[0065] (4) The industrial control computer data management unit 42 receives the lightning current signal obtained from the lightning current measuring oscilloscope 31-2 and the lightning current sensor 31-1 measured by the pulse current sensor 31-1, as well as the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group S32-11 to S32-14 at the lightning strike center point directly below the lower surface of the test sample 2, at 45° angle, -45° angle and 180° angle, measured by the first impact force measuring oscilloscope 32-21 and the second impact force measuring oscilloscope 32-22.

[0066] (5) The control unit 41 processes the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group S32-11 to S32-14 of the lightning strike, analyzes the waveform differences of the piezoelectric signals obtained by the multi-dimensional impact force piezoelectric sensor group S32-11 to S32-14 of the lightning strike multi-dimensional impact force measurement unit 3 under different source impedance lightning strike currents, obtains the waveform characteristics of the multi-dimensional lightning impact force waveform, especially the piezoelectric signal of the 0° center piezoelectric sensor S32-11 on the lower surface of the test sample 2, and the intrinsic correlation between the lightning current wind peak parameter and the thermoelectric state of the surface of the test sample 2, and analyzes the temporal superposition relationship of the electromagnetic force and the shock wave generated by the surface explosion during the lightning strike and the test sample 2.

[0067] (6) Analyze the difference in lightning impact force between the lightning current and the metal plate and carbon fiber composite laminate under the lightning conduction injection mode, and obtain the intrinsic relationship between the shock wave generated by the explosion on the surface of the test sample 2 and the lightning current amplitude parameters, as well as the surface structure state of the test metal plate and carbon fiber composite laminate.

[0068] See Figure 5 The specific process of the temporal sequence relationship of the multidimensional impact force of lightning, the electromagnetic force of lightning, the explosive impact force on the surface of the test object, and the acoustic shock wave generated by the expansion of the arc channel is as follows:

[0069] (1) Electrically connect the lightning current source 1 with controllable source impedance and intensity, the test sample 2, the lightning multi-dimensional impact force measurement unit 3, and the computer control and data management unit 4.

[0070] (2) Metal plate and carbon fiber composite laminate 2-2 were selected as test specimens 2 respectively, and the lightning current source was injected into the center point of test specimen 2 by direct electric arc or the action gap method.

[0071] (3) Select the source impedance of the lightning current source 1 with controllable source impedance and intensity, wherein the source impedance has at least 3 resistance values. The source impedance of the lightning current source is controlled by the programmable controller 41-2 of the lightning multidimensional impact force test control unit, and the discharge voltage of the adjustable source impedance lightning current generating unit 1-2 is controlled by controlling the charging voltage of the adjustable high voltage DC charging power supply 1-1, so as to ensure that reliable discharge can occur under different arc injection gaps.

[0072] (4) Under the condition of setting the discharge voltage, the multidimensional lightning impact force of the lightning discharge circuit is tested by selecting different arc gaps and different source impedances.

[0073] (5) The industrial control computer data management unit 42 receives the lightning current signal obtained from the lightning current measuring oscilloscope 31-2 and the lightning current sensor 31-1 measured by the pulse current sensor 31-1, as well as the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group S32-11 to S32-14 at the lightning strike center point directly below the lower surface of the test sample 2, at 45° angle, -45° angle and 180° angle, measured by the first impact force measuring oscilloscope 32-21 and the second impact force measuring oscilloscope 32-22.

[0074] (6) The industrial control computer data management unit 42 processes the piezoelectric signals output by the multidimensional impact force piezoelectric sensor group S32-11 to S32-14 of the lightning strike, analyzes the waveform differences of the piezoelectric signals obtained by the multidimensional impact force measurement unit 3 of the test sample 2 under different source impedance lightning currents, obtains the waveform characteristics of the multidimensional lightning impact force waveform, especially the piezoelectric signal of the 0° piezoelectric sensor S32-11 at the center of the lower surface of the test sample, during the lightning strike, and obtains the intrinsic correlation between the action gap distance of the electric arc injection, the different source impedances or lightning current amplitude parameters, and the thermoelectric state of the surface of the test sample 2, and analyzes the temporal superposition relationship of the electromagnetic force, the shock wave generated by the surface explosion and the acoustic shock wave generated by the expansion of the electric arc channel during the lightning strike and the test sample 2.

[0075] (7) Analyze the differences in the lightning impact force of lightning current on metal plates and carbon fiber composite laminates under the lightning arc gap injection mode, and obtain the intrinsic relationship between electromagnetic force, shock wave generated by surface explosion, acoustic shock wave generated by arc channel expansion, different source impedance or lightning current amplitude parameters, arc injection gap distance, and surface structure state of the tested metal plates and carbon fiber composite laminates.

[0076] By integrating point contact conduction injection, arc gap injection, and different source impedance generation circuits, the multidimensional lightning impact force characteristics are analyzed and the temporal superposition relationship of lightning electromagnetic force, shock wave generated by surface explosion, and acoustic shock wave generated by arc channel expansion in carbon fiber composites is obtained. This lays the foundation for the analysis of lightning damage to carbon fiber composites under multi-physics field coupling of thermal, electrical, and mechanical fields, as well as the design and evaluation of lightning protection for carbon fiber composites.

Claims

1. A multi-dimensional impact testing system for carbon fiber composite laminates struck by lightning, characterized in that: It includes a lightning current source with controllable source impedance and intensity (1), a test sample (2), a multi-dimensional lightning impact force measurement unit (3), and a computer control and data management unit (4); The controllable source impedance and intensity lightning current source (1) includes three parts: an adjustable high voltage DC charging power supply (1-1), an adjustable source impedance lightning current generating unit (1-2), and a charging voltage monitoring sensor (1-3), which are used to generate lightning current waves with adjustable source impedance and intensity; the test specimen (2) is a plate-shaped metal plate or a carbon fiber composite laminate. During the test, the test specimen (2) is connected in the circuit of the adjustable source impedance lightning current generating unit (1-2). The lightning current is injected from the center of the test specimen (2) and flows back from the two opposite end faces or four end faces of the test specimen (2); The multi-dimensional lightning impact force measurement unit (3) includes a multi-dimensional lightning impact force sensing and measuring mechanism, a recording device, and an industrial control computer; the multi-dimensional lightning impact force sensing and measuring mechanism is installed on the lower surface of the test sample, and the piezoelectric signal output of the test is connected to the recording device. The recording device transmits the collected and recorded lightning current and piezoelectric signals to the industrial control computer for analysis, processing, and result output of the lightning current signal and lightning impact force signal. The computer control and data management unit (4) monitors and controls the generation circuit, discharge voltage and working process of the lightning current source (1) with controllable source impedance and intensity.

2. The multi-dimensional impact force testing system for carbon fiber composite laminates under lightning strikes according to claim 1, characterized in that: The adjustable high-voltage DC charging power supply (1-1) includes a voltage regulator T1, a transformer T2, a current-limiting resistor Rc, and a rectifier silicon stack D; the adjustable source impedance lightning current generating unit (1-2) consists of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L, and a resistor R connected in series to form a circuit, with the test sample and its clamping fixture connected in series in the circuit; the output current amplitude of the adjustable source impedance lightning current generating unit (1-2) is controlled by the charging voltage of the adjustable high-voltage DC charging power supply (1-1).

3. The multi-dimensional impact testing system for carbon fiber composite laminates struck by lightning according to claim 1, characterized in that: The energy storage capacitors in the adjustable source impedance lightning current generating unit (1-2) are multiple capacitors C1, C2, and C3. The capacitors C1, C2, and C3 can be operated independently or in parallel through high-voltage switches K11, K12, and K13. Similarly, the tuning inductors L1, L2, and L3 and the tuning resistors R1, R2, and R3 can be operated independently or in parallel through selection switches K21, K22, and K23, thus realizing the adjustment of the source impedance of the adjustable source impedance lightning current generating unit (1-2).

4. The multi-dimensional impact force testing system for carbon fiber composite laminates struck by lightning according to claim 1, characterized in that: The selection of capacitors C1, C2, C3, as well as tuning inductors L1, L2, L3 and tuning resistors R1, R2, R3 in series are all automatically adjusted. The test sample (2) is connected in series in the adjustable source impedance lightning current generating unit (1-2), and a pulse current sensor (31-1) is connected to the low-voltage output connection bus of the adjustable source impedance lightning current generating unit (1-2) of the sample and the lightning current source (1) with controllable source impedance and intensity.

5. The multi-dimensional impact force testing system for carbon fiber composite laminates struck by lightning according to claim 1, characterized in that: The multidimensional lightning impact force sensing and measurement mechanism comprises a lightning impact force transmission mechanism, an impact force piezoelectric sensor, and a shielding mechanism. The piezoelectric signal output from the impact force piezoelectric sensor is connected to a recording device, which is an oscilloscope or a data acquisition system. The multidimensional lightning strike force sensing and measurement mechanism specifically includes a pulse current sensor (31-1) and a lightning current measurement oscilloscope (31-2), a multidimensional lightning strike force transmission and measurement sensor group (32-1), a first impact force measurement oscilloscope (32-21), and a second impact force measurement oscilloscope (32-22); The lightning current measuring oscilloscope (31-2) receives and detects the lightning current signal of the controlled source impedance and intensity of the lightning current source (1) acting on the test object (2) extracted by the pulse current sensor (31-1); the lightning current measuring oscilloscope (31-2) and the multi-dimensional lightning impact force transmission and measurement sensor group (32-1) detect the lightning impact force of the test object (2) in multiple dimensions, and analyze the lightning current and lightning impact force signals to obtain the intrinsic correlation between the multi-dimensional lightning impact force and the lightning current electrical parameters borne by the test object (2).

6. The multi-dimensional impact force testing system for lightning strikes on carbon fiber composite laminates according to claim 1, characterized in that: The multidimensional lightning impact force transmission and measurement sensor group (32-1) is installed on the lower surface of the test sample (2), including a lightning impact force transmission mechanism (a), a mounting base plate (k) set at the center of the lower surface of the test sample (2), and a 45° angle at a certain distance from the center. 0 Angle, -45 0 Angle and 180 0 A multi-dimensional lightning impact piezoelectric sensor group (S32-11) to (S32-14) and a shielding mechanism (b) are set at four angles; the piezoelectric signals measured by the multi-dimensional lightning impact piezoelectric sensor group (S32-11) to (S32-14) are output and connected to the first impact force measuring oscilloscope (32-21) and the second impact force measuring oscilloscope (32-22) or a data acquisition system; the lightning current measuring oscilloscope (31-2) and the first impact force measuring oscilloscope (32-21) and the second impact force measuring oscilloscope (32-22) then transmit the collected and recorded lightning current and multi-dimensional lightning impact piezoelectric signals to the industrial control computer respectively.

7. The multi-dimensional impact force testing system for carbon fiber composite laminates struck by lightning according to claim 1, characterized in that: The multidimensional lightning impact force transmission and measurement sensor group (32-1) is installed on the support base plate (i). Two parallel sample fixtures (j) are installed on the support base plate (i) at a certain distance. The test sample (2) is fixed and clamped by the metal support strips / blocks (f) and crimping strips / blocks (e) of the two sample fixtures through fastening bolts. The horizontal ends of the test sample (2) are respectively connected to the low-voltage output port of the lightning current source (1) with controllable source impedance and intensity through the metal support strips / blocks (f) of the sample fixtures. The high-voltage output terminal of the adjustable source impedance lightning current generating unit (1-2) is injected through the high-voltage injection electrode (c) set above the center of the test sample (2). The distance between the high-voltage injection electrode (c) and the center point of the upper surface of the test sample (2) can be adjusted.

8. A method for analyzing the timing of multidimensional impact forces from lightning strikes on carbon fiber composite laminates based on the test system described in any one of claims 1-7, characterized in that: By adjusting the source impedance and intensity of the lightning current source, lightning current is injected into the center of the test sample (2) through conduction or lightning arc injection. Metal plate and carbon fiber composite laminate are selected as test samples respectively. The piezoelectric signal measured by the multidimensional lightning impact force piezoelectric sensor group in the multidimensional lightning impact force transmission and measurement sensor group (32-1) on the lower surface of the test sample is analyzed. The temporal relationship between the electromagnetic force of lightning and the explosive impact force on the surface of the test object was analyzed in the multidimensional impact force of lightning strikes obtained under the lightning conduction and injection lightning current mode. The difference in the lightning impact force of lightning current on metal plate and carbon fiber composite laminate was analyzed under the lightning conduction and injection lightning current mode. The intrinsic relationship between the shock wave generated by the explosion on the surface of the test object (2) and the lightning current amplitude parameters, as well as the surface structural state of the test metal plate and carbon fiber composite laminate was obtained. Analyze the temporal superposition relationship of electromagnetic force, surface explosion shock wave and arc channel expansion generated during the interaction between lightning strike and test sample (2) under the lightning current injection mode; The study analyzes the differences in the lightning impact force exerted by the lightning current on metal plates and carbon fiber composite laminates under different lightning arc injection modes. It obtains the intrinsic relationship between electromagnetic force, shock wave generated by surface explosion, acoustic shock wave generated by arc channel expansion, different source impedance or lightning current amplitude parameters, arc injection gap distance, and surface structural state of the tested metal plates and carbon fiber composite laminates.

9. The method for analyzing the timing of multidimensional impact forces from lightning strikes on carbon fiber composite laminates as described in claim 8, characterized in that... The specific process for analyzing the temporal relationship of the multidimensional impact force of lightning in the spatiotemporal superposition under the lightning conduction and injection current mode is as follows: (1) Electrically connect the controllable source impedance and intensity lightning current source (1), the test sample (2), the lightning multi-dimensional impact force measurement unit (3), and the computer control and data management unit (4); (2) Metal plates and carbon fiber composite laminates were selected as test samples (2) respectively, and the lightning current source was injected into the center point of the test sample (2) by direct electrical contact. (3) Select a lightning current source (1) with controllable source impedance and intensity. The output current intensity of the lightning current source (1) has at least 5 current levels. The programmable controller 41-2 of the lightning multidimensional impact force test control unit controls the charging voltage of the adjustable high voltage DC charging power supply (1-1) to control the output current intensity of the adjustable source impedance lightning current generating unit (1-2), so that the lightning impact current flowing through the test object (2) reaches different amplitudes. (4) The computer control and data management unit (4) receives the lightning current signal obtained from the lightning current measurement oscilloscope (31-2) and the pulse current sensor (31-1) measured by the pulse current sensor (31-1), as well as the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group (S32-11) to (S32-14) at the lightning strike center point directly below the lower surface of the test specimen (2), at 45° angle, -45° angle and 180° angle measured by the first impact force measurement oscilloscope (32-21) and the second impact force measurement oscilloscope (32-22); (5) The computer control and data management unit (4) processes the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group (S32-11) to (S32-14) under different source impedance lightning currents, analyzes the waveform differences of the piezoelectric signals obtained by the multi-dimensional impact force piezoelectric sensor group (S32-11) to (S32-14) under different source impedance lightning currents, obtains the waveform characteristics of the multi-dimensional lightning impact force waveform, the piezoelectric signal of the 0° center piezoelectric sensor (S32-11) on the lower surface of the test object (2), the intrinsic correlation between the lightning current wind peak parameter and the thermoelectric state of the test object (2), and analyzes the temporal superposition relationship of the electromagnetic force and the shock wave generated by the surface explosion during the lightning strike and the test object (2). (6) Analyze the difference in lightning impact force between the lightning current and the metal plate and carbon fiber composite laminate under the lightning conduction injection mode, and obtain the intrinsic relationship between the shock wave generated by the explosion on the surface of the test sample (2) and the lightning current amplitude parameters, as well as the surface structure state of the test metal plate and carbon fiber composite laminate.

10. The method for analyzing the timing of multidimensional impact forces from lightning strikes on carbon fiber composite laminates as described in claim 8, characterized in that... The specific process for analyzing the temporal relationship of the multidimensional impact force of lightning in the spatiotemporal superposition under the lightning current injection mode of lightning arc is as follows: (1) Electrically connect the controllable source impedance and intensity lightning current source (1), the test sample (2), the lightning multi-dimensional impact force measurement unit (3), and the computer control and data management unit (4); (2) Metal plates and carbon fiber composite laminates were selected as test samples (2), and the lightning current source was injected into the center point of the test sample (2) by direct electric arc or action gap method. (3) Select the source impedance of the lightning current source (1) with controllable source impedance and intensity, wherein the source impedance has at least 3 resistance values. The source impedance of the lightning current source is controlled by the lightning multidimensional impact force test control unit, and the discharge voltage of the adjustable source impedance lightning current generation unit (1-2) is controlled by controlling the charging voltage of the adjustable high voltage DC charging power supply (1-1) to ensure reliable discharge under different arc injection gaps. (4) Under the condition of setting the discharge voltage, the multidimensional lightning impact force of the lightning discharge circuit is tested by selecting different arc gaps and different source impedances. (5) The industrial control computer receives the lightning current signal obtained from the lightning current measuring oscilloscope (31-2) and the pulse current sensor (31-1) measured by the pulse current sensor (31-1), as well as the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group (S32-11) to (S32-14) at the lightning strike center point directly below the lower surface of the test sample (2), at 45° angle, -45° angle and 180° angle measured by the first impact force measuring oscilloscope (32-21) and the second impact force measuring oscilloscope (32-22); (6) The industrial control computer processes the piezoelectric signals output by the multi-dimensional impact force piezoelectric sensor group (S32-11) to (S32-14) under different source impedance lightning currents, analyzes the waveform differences of the piezoelectric signals obtained by the multi-dimensional impact force piezoelectric sensor group (S32-11) to (S32-14) under different source impedance lightning currents, obtains the waveform characteristics of the multi-dimensional lightning impact force waveform, especially the piezoelectric signal of the 0° piezoelectric sensor (S32-11) at the center of the lower surface of the test object, and the intrinsic correlation between the arc injection gap distance, different source impedances or lightning current amplitude parameters, and the thermoelectric state of the test object (2) surface, and analyzes the temporal superposition relationship of the electromagnetic force, the shock wave generated by the surface explosion and the acoustic shock wave generated by the arc channel expansion during the interaction between the lightning and the test object (2). (7) Analyze the differences in the lightning impact force of lightning current on metal plates and carbon fiber composite laminates under the lightning arc gap injection mode, and obtain the intrinsic relationship between electromagnetic force, shock wave generated by surface explosion, acoustic shock wave generated by arc channel expansion, different source impedance or lightning current amplitude parameters, arc injection gap distance, and surface structure state of the tested metal plates and carbon fiber composite laminates.

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