Full-waveform measuring device and method for axial load of lightning stroke impact force of carbon fiber composite laminated plate

Abstract

The invention discloses a full-waveform measuring device and method for an axial load of lightning impact force of a carbon fiber composite laminate, and the device comprises a controllable intensity lightning current source, a tested carbon fiber composite laminate, and a lightning impact force test control and measurement analysis unit. Impact force acting on the upper portion of the tested carbon fiber composite material laminated plate is transmitted to the piezoelectric sensor through the stress wave transmission mechanism transmission unit, so that the piezoelectric sensor obtains signals generated under extrusion of stress waves formed by real lightning stroke without reflection waves, and the amplitude of lightning current output by the intensity-controllable lightning current source is adjusted. Obtaining a mathematical analysis formula and time response characteristics between an axial lightning impact force generated when a lightning current acts on the tested material and lightning current electrical parameters, and obtaining a relation rule between the lightning damage morphology and damage degree of the carbon fiber composite material and the axial lightning impact force; and a theoretical support is provided for research on a lightning damage mechanism of the tested carbon fiber composite material laminated plate.

Description

Technical Field

[0001] The invention belongs to the field of measuring mechanical effects of lightning strikes on materials, and relates to a device and method for measuring the full waveform of the axial load of lightning strike impact force on a carbon fiber composite laminate. Background Art

[0002] Carbon fiber composite materials have the characteristics of low density, high strength, high modulus, high temperature resistance, chemical corrosion resistance, etc. They are widely used in various fields such as aerospace, military and civil industries. The use of carbon fiber composite materials in aircraft structures has also increased significantly. For example, the use of carbon fiber in Airbus A350 and Boeing 787 is more than 50%. The amount of composite materials has become one of the important indicators for evaluating the advancement of aircraft. High-intensity lightning strikes can cause serious damage to the matrix of carbon fiber composite materials, such as pyrolysis, fiber breakage, and deep stratification. Therefore, lightning damage and lightning protection of carbon fiber composite materials have become a technical problem that restricts the use of carbon fiber.

[0003] The direct effects of lightning on aircraft include not only arc heat and Joule heat caused by large currents, but also complex mechanical effects. The American Society of Automotive Engineers (SAE), the US military standard MIL STD, and the European Civil Aviation Organization (EUROCAE) have made detailed provisions on the test waveforms and test methods for the direct effects of lightning on aircraft and their components. At present, the damage caused by resin pyrolysis and carbon fiber sublimation under the condition of lightning thermal effects of carbon fiber composite materials is explained through experimental and simulation calculation studies on lightning damage of carbon fiber composite materials. Relevant literature proves that the mechanical effects in the lightning process cannot be ignored, and decomposes the mechanical effects into acoustic shock waves, electromagnetic forces, and shock waves generated by surface explosions generated by the expansion of the arc channel. Under the coupling effect of the axial component of the lightning impact force and the Joule thermal effect, the damage caused by lightning to the composite structure will inevitably be aggravated. However, the currently available literature cannot provide an accurate and complete characterization.

[0004] Invention patent CN 111609958 discloses a method for reducing lightning impact force of carbon fiber composite materials, but the following deficiencies were found during the research process:

[0005] (1) The piezoelectric sensor under test is installed on an insulating plate fixed to the bottom surface of the metal shielding shell. Due to the influence of the stiffness of the insulating plate material, part of the stress is absorbed, thus affecting the measurement accuracy of the piezoelectric sensor's response amplitude to the lightning stress wave;

[0006] (2) The piezoelectric sensor under test is placed between the impact force transmission rod with different materials and the insulating support plate above the metal shielding shell. When the stress wave is transmitted between different media, the stress wave reflection phenomenon will occur. The transmission of the stress wave between the transmission rod-support plate-shielding shell is complicated, which affects the integrity and authenticity of the lightning wave signal measured by the piezoelectric sensor.

[0007] (3) The tested lightning impulse force transmission unit is in close contact with the piezoelectric sensor, ignoring the fact that the piezoelectric effect of the piezoelectric sensor is related to the effective action area, which affects the accuracy of the lightning impulse force measurement;

[0008] (4) When studying the instantaneous relationship between lightning impulse force and lightning current response time, the transmission time of the lightning stress wave in the transmission rod was ignored, causing a phase deviation between the lightning current and the impulse force, which will have a certain impact on the research on the lightning damage mechanism of carbon fiber composite materials; in the long run, the measurement deviation will also affect the design of carbon fiber composite lightning protection structures. Summary of the invention

[0009] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a full-waveform measurement device for the axial load of lightning impact force of carbon fiber composite laminates, so as to obtain the relationship between lightning impact force and lightning damage of the tested carbon fiber composite laminates, and lay a foundation for the study of lightning damage mechanism of carbon fiber composites and the design of composite lightning protection structures.

[0010] The present invention is achieved through the following technical solutions:

[0011] A full-waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate, comprising a controllable intensity lightning current source, a tested carbon fiber composite laminate and a lightning impact force test control and measurement analysis unit;

[0012] The controllable intensity lightning current source is used to generate lightning current shock waves, including a controllable high-voltage DC charging power supply, a lightning current generating unit and a charging voltage monitoring sensor;

[0013] The tested carbon fiber composite material laminate is connected in a lightning current generating unit circuit;

[0014] The lightning impulse test control and measurement and analysis unit includes a lightning impulse test control unit and a measurement and analysis unit; the lightning impulse test control and measurement and analysis unit monitors and controls the operation of the controllable intensity lightning current source through the control unit and the measurement and analysis unit;

[0015] The lightning impulse force test control and measurement and analysis unit controls a controllable intensity lightning current source to apply lightning impulse currents of different amplitudes to the tested carbon fiber composite laminate; and simultaneously receives a lightning current signal acting on the tested carbon fiber composite laminate, and a piezoelectric signal generated by the lightning impulse force borne by the tested carbon fiber composite laminate, and analyzes the lightning current and lightning impulse force signals to obtain a relationship between the lightning impulse force borne by the carbon fiber composite laminate and the electrical parameters of the lightning current.

[0016] Preferably, the controllable high-voltage DC charging power supply adopts a voltage doubling charging method, and the lightning current generating unit is 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 loop, and the tested carbon fiber composite laminate and its clamping fixture are connected in series in the loop.

[0017] Preferably, the lightning impulse force test control unit includes a charging voltage monitoring circuit and a PLC programmable controller; the lightning impulse force measurement and analysis unit includes a current sensor, a lightning axial impulse force loading and transfer measurement unit, a digital oscilloscope and an industrial control computer, and the current sensor is sleeved on the electrical connection bus between the tested carbon fiber composite laminate and the controllable intensity lightning current source;

[0018] The lightning axial impact force loading and transmission measurement unit includes a lightning impact force stress wave loading and transmission system and a lightning impact force piezoelectric measurement sensor unit, which can realize the measurement of the full waveform of the lightning impact force of the carbon fiber composite laminate;

[0019] The oscilloscope is used to receive the lightning current signal output by the controllable intensity lightning current source extracted by the current sensor, and receive the piezoelectric signal output by the lightning impulse force piezoelectric measurement sensor unit; the oscilloscope collects and records the lightning current and piezoelectric signals and transmits them to the industrial control computer respectively, and analyzes, processes and outputs the lightning current signal and lightning impulse force signal.

[0020] Preferably, the lightning impulse force stress wave loading and transmission system comprises a supporting base plate, two test fixtures separately arranged on the supporting base plate, and the test fixtures comprise an insulating support block, a metal support strip or block and a crimping strip or block arranged in sequence from bottom to top;

[0021] The tested carbon fiber composite laminate is fixedly clamped by metal support bars or blocks and crimping bars or blocks of two test fixtures through fastening bolts, and the lower surface of the tested carbon fiber composite laminate is in contact with a shielded piezoelectric measurement sensor unit containing a stress wave transmission system for lightning impulse force; the horizontal ends of the tested carbon fiber composite laminate are connected to the low-voltage output port of a controllable intensity lightning current source through the respective metal support bars or blocks of the test fixture; the lightning current flowing into the tested carbon fiber composite laminate is injected from a metal rod-shaped electrode arranged above the center thereof, and the distance between the metal rod-shaped electrode and the upper surface of the tested carbon fiber composite laminate can be adjusted.

[0022] Preferably, the shielded lightning impulse force piezoelectric measurement sensor unit comprises a metal shielding shell, a stress wave transmission mechanism and a piezoelectric sensor arranged in the metal shielding shell;

[0023] The stress wave transmission mechanism comprises a transmission unit, a support unit and an absorbing unit; the top surface of the transmission unit passes through the metal shielding shell and is in close contact with the center of the lower surface of the tested carbon fiber composite laminate, the lower end surface is in contact with the upper end surface of the support unit, and the lower end of the support unit is fixed to the absorbing unit arranged on the bottom surface of the metal shielding shell; the piezoelectric sensor is installed between the lower surface of the transmission unit and the upper surface of the support unit;

[0024] The BNC coaxial connector and the BNC coaxial connector arranged on one side of the metal shielding shell are electrically connected to the upper electrode and the lower electrode of the piezoelectric sensor respectively; the shock wave formed by the lightning acting on the tested carbon fiber composite laminate is transmitted through the transmission unit to form a uniformly distributed stress wave to squeeze the piezoelectric sensor, and a piezoelectric signal is output between the upper electrode and the lower electrode of the piezoelectric sensor, which is transmitted to the digital oscilloscope and the industrial control computer in the measurement and analysis unit of the lightning impulse force through the BNC coaxial connector and the BNC coaxial connector.

[0025] Preferably, the transmission unit and the support unit are insulating rods with a circular or square cross-section, and the length of the insulating rod is greater than or equal to 10 times the diameter or width of the cross-section; the absorbing unit is an insulating plate with strong absorbing ability, and the piezoelectric sensor is made of piezoelectric crystals, piezoelectric ceramics or piezoelectric film materials.

[0026] The method for measuring the full waveform of the axial load of the lightning impact force of the carbon fiber composite laminate comprises the following steps:

[0027] (1) Connect the controllable intensity lightning current source, the tested carbon fiber composite laminate, and the lightning impulse force test control and measurement analysis unit together;

[0028] (2) Select no less than 5 lightning impulse current intensity points, and control the charging voltage across the energy storage capacitor of the controllable intensity lightning current source through the PLC programmable controller of the lightning impulse test control unit, so that the impact intensity acting on the tested carbon fiber composite laminate and the lightning impulse current flowing through it reach different amplitudes;

[0029] (3) The industrial control computer receives the lightning current signal measured by the current sensor obtained from the digital oscilloscope, and at the same time, the industrial control computer receives the piezoelectric signal corresponding to the electrical parameters of the lightning current output by the piezoelectric sensor;

[0030] (4) The industrial control computer processes and analyzes the received signal to obtain the axial lightning impulse force borne by the tested carbon fiber composite laminate and the lightning current parameters acting on the tested carbon fiber composite laminate. The industrial control computer analyzes and processes the signal to obtain the mathematical expression between the axial lightning impulse force and the lightning current parameters generated when the lightning current acts on the tested carbon fiber composite laminate;

[0031] (5) After the experiment on the relationship between axial lightning impulse force and lightning current parameters is completed, ultrasonic scanning is used to obtain the lightning damage morphology, damage area, and damage depth of the tested carbon fiber composite laminates under different lightning current parameters, and the relationship between the axial lightning impulse force and the lightning damage of the tested carbon fiber composite laminates is obtained.

[0032] The present invention has the following beneficial effects:

[0033] The present invention discloses a full-waveform measuring device and method for axial lightning impact force of carbon fiber composite materials with reliable transmission and wave reflection-free performance transmission structure, and an axial load full-waveform measuring device, including a controllable intensity lightning current source, a test carbon fiber composite laminate and a lightning impact force test control and measurement analysis unit. The impact force acting on the top of the test carbon fiber composite laminate is transmitted to the piezoelectric sensor via a transmission unit in a stress wave transmission mechanism whose length is ten times the cross-sectional diameter. Under the joint action of the supporting unit in the stress wave transmission mechanism, the piezoelectric sensor obtains a signal generated by the extrusion of the stress wave formed by a real lightning strike without a reflection wave.

[0034] The piezoelectric sensing unit is designed with a metal shielding shell that suppresses the strong electromagnetic interference of the external lightning environment, so that the measurement of the lightning impulse force on the tested carbon fiber composite laminate can be free from the influence of strong lightning current electromagnetic interference. The tested carbon fiber composite laminate is clamped at both ends horizontally, and the impact force generated by the lightning current impact is measured by the piezoelectric sensing unit with electromagnetic shielding function, which can accurately and completely measure the axial lightning impulse force. At the same time, the time phase relationship between the generated axial lightning impulse force and the lightning current can be obtained by combining the transmission properties of the stress wave transmission mechanism.

[0035] At the same time, by adjusting the amplitude of the lightning current output by the controllable intensity lightning current source, the mathematical analytical expression and time response characteristics between the axial lightning impulse force and the lightning current electrical parameters generated when the lightning current acts on the tested carbon fiber composite laminate are obtained, and the relationship between the lightning damage morphology and damage degree of the carbon fiber composite material and the axial lightning impulse force are obtained, providing theoretical support for the study of the lightning damage mechanism of the tested carbon fiber composite laminate.

[0036] The measurement method of lightning impulse force on carbon fiber composite materials, combined with non-destructive testing of carbon fiber composite materials, obtains the relationship between lightning impulse force and lightning damage of the tested carbon fiber composite laminates, laying the foundation for the study of lightning damage mechanism of carbon fiber composite materials and the design of composite lightning protection structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a block diagram of the full waveform measurement device for the axial load of the impact force of lightning on the carbon fiber composite material laminate under strong electromagnetic interference of the present invention;

[0038] Figure 2 It is a schematic diagram of a controllable intensity lightning current source of a full waveform measuring device for the axial load of the impact force of lightning on a carbon fiber composite laminate under strong electromagnetic interference of the present invention;

[0039] Figure 3 It is a schematic structural diagram of a lightning axial impact force loading and transmission measurement unit of a full-waveform measurement device for measuring the axial load of the impact force of lightning on a carbon fiber composite material laminate under strong electromagnetic interference of the present invention;

[0040] Figure 4 It is a structural schematic diagram of a shielded piezoelectric measurement sensor unit for lightning impulse force in the present invention;

[0041] Figure 5 It is a flow chart of the full waveform measurement method of the axial load of the impact force of lightning on carbon fiber composite material laminates under strong electromagnetic interference of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0043] See also Figure 1 The present invention provides a full-waveform measuring device for the axial load of lightning impact force of a carbon fiber composite laminate with a reliable transmission and wave-reflection-free performance transmission structure, comprising a controllable intensity lightning current source 1, a tested carbon fiber composite laminate 2 and a lightning impact force test control and measurement analysis unit 3.

[0044] See also Figure 1 The function of the controllable intensity lightning current source 1 is to generate lightning current shock waves, and it mainly includes three parts: a controllable high-voltage DC charging power supply 1-1, a lightning current generating unit 1-2 and a charging voltage monitoring sensor 1-3.

[0045] See also Figure 1 The lightning impulse test control and measurement and analysis unit 3 includes a lightning impulse test control unit 31 and a measurement and analysis unit 32. The lightning impulse test control unit 31 is mainly composed of a charging voltage monitoring circuit 31-1 and a PLC programmable controller 31-2, which can realize the process control of the lightning impulse test of composite materials; the lightning impulse measurement and analysis unit 32 is mainly composed of a current sensor 32-1, a lightning axial impulse loading and transfer measurement unit 32-2, a digital oscilloscope 32-3 and an industrial control computer 32-4.

[0046] The lightning impulse test control and measurement and analysis unit 3 monitors and controls the operation of the controllable intensity lightning current source 1 through the control unit 31 and the measurement and analysis unit 32, and simultaneously receives the lightning current signal of the controllable intensity lightning current source 1 acting on the test carbon fiber composite laminate 2 extracted by the current sensor 32-1, and the lightning impulse force borne by the test carbon fiber composite laminate 2 detected by the piezoelectric sensor 32-2-2-3 unit, and analyzes the lightning current and lightning impulse force signals to obtain the intrinsic correlation between the lightning impulse borne by the carbon fiber composite laminate 2 and the lightning current electrical parameters.

[0047] See also Figure 2 The controllable high-voltage DC charging power supply 1-1 adopts a double-voltage charging method to avoid corona discharge during the discharge process; the lightning current generating unit 1-2 is mainly composed of a pulse energy storage capacitor C, a high-voltage discharge switch G, a waveform forming inductor L and a resistor R, which are electrically connected in series, and the tested carbon fiber composite laminate 2 and its clamping fixture are connected in series in a loop composed of the pulse energy storage capacitor C, the high-voltage discharge switch G, the waveform forming inductor L and the resistor R; the current sensor 32-1 is connected to the electrical connection bus between the sample and the controllable intensity lightning current source 1.

[0048] See also Figure 3 The lightning axial impact force loading and transfer measurement unit 32-2 mainly includes a lightning impact force stress wave loading and transfer system 32-2-1 and a lightning impact force piezoelectric measurement sensor unit 32-2-2, which can realize the measurement and analysis of the full waveform of the lightning impact force of the carbon fiber composite laminate 2.

[0049] See also Figure 3 The lightning impulse stress wave loading and transmission system 32-2-1 is composed of a supporting base plate 32-2-1-1, an insulating support block 32-2-1-2, metal support strips or blocks 32-2-1-3 and crimping strips or blocks 32-2-1-4 on both sides, fastening bolts 32-2-1-5, and metal rod electrodes 32-2-1-6; the tested carbon fiber composite laminate 2 is composed of metal support strips or blocks 32-2-1-3 and crimping strips or blocks 32-2-1-4 on both sides of the fixture through fastening bolts 32-2-1 -5 fixed clamp, and keep both ends horizontal; the lower surface of the tested carbon fiber composite laminate 2 is in contact with the shielded lightning impulse force piezoelectric measurement sensor unit 32-2-2 containing the stress wave transmission system; the horizontal ends of the tested carbon fiber composite laminate 2 are connected to the low-voltage output port of the controllable intensity lightning current source 1 through the respective metal support bars or blocks 32-2-1-3 on both sides of the test fixture; the lightning current flowing into the tested carbon fiber composite laminate 2 is injected from the metal rod-shaped electrode 32-2-1-6 above its center. The distance between the metal rod-shaped electrode 32-2-1-6 and the upper surface of the tested carbon fiber composite laminate 2 can be adjusted.

[0050] See also Figure 3 and Figure 4 The shielded piezoelectric measurement sensor unit 32-2-2 for lightning impulse force comprises a metal shielding shell 32-2-2-1, a stress wave transmission mechanism 32-2-2-2, a piezoelectric sensor 32-2-2-3, a BNC coaxial connector 32-2-2-4 and a BNC coaxial connector 32-2-2-5. The piezoelectric sensor 32-2-2-3 in the shielded piezoelectric measurement sensor unit 32-2-2 is at the same height as the BNC coaxial connector 32-2-2-4 and the BNC coaxial connector 32-2-2-5, and the electrical connection between the two ensures that the piezoelectric sensor 32-2-2-3 will not be deformed.

[0051] See also Figure 3 and Figure 4The stress wave transmission mechanism 32-2-2-2 in the shielded lightning impulse force piezoelectric measurement sensor unit 32-2-2 includes a transmission unit 32-2-2-2-1, a support unit 32-2-2-2-2, and an absorbing unit 32-2-2-2-3; the top end surface of the transmission unit 32-2-2-2-1 is in close contact with the center of the lower surface of the tested carbon fiber composite laminate 2, and passes through the metal shielding shell 32-2-2-1, and the lower end surface is in contact with the upper end surface of the support unit 32-2-2-2-2 of the same material and the same size, and the support unit 32-2-2- The lower end of 2-2 is fixed to the absorbing unit 32-2-2-2-3; the piezoelectric sensor 32-2-2-3 is installed between the lower surface of the transmission unit 32-2-2-2-1 and the upper surface of the support unit 32-2-2-2-2; the BNC coaxial connector 32-2-2-4 and the BNC coaxial connector 32-2-2-5 are arranged on one side of the piezoelectric sensor 32-2-2-3, at the same height as the piezoelectric sensor 32-2-2-3, and are electrically connected to the upper electrode and the lower electrode of the piezoelectric sensor 32-2-2-3 respectively; act on the tested carbon fiber composite laminate The shock wave formed by the lightning of 2 is transmitted through the transmission unit 32-2-2-2-1 in the stress wave transmission mechanism to form a uniformly distributed stress wave, which squeezes the piezoelectric sensor 32-2-2-3, outputs a piezoelectric signal between the upper electrode and the lower electrode of the piezoelectric sensor 32-2-2-3, and transmits it to the digital oscilloscope 32-3 and the industrial control computer 32-4 in the lightning impulse force measurement and analysis unit 32 through the BNC coaxial connector 32-2-2-4 and the BNC coaxial connector 32-2-2-5; the transmission unit 32-2-2 of the stress wave transmission mechanism 32-2-2-2 32-2-2-2-1, the supporting unit 32-2-2-2-2 is an insulating rod made of ceramic, the cross-section of the insulating rod is round or square, and the length of the insulating rod is greater than or equal to 10 times the cross-sectional size; the absorbing unit 32-2-2-2-3 is an insulating board with strong absorbing ability, and the material is epoxy board; the piezoelectric sensor 32-2-2-3 is made of piezoelectric crystal, piezoelectric ceramic or piezoelectric film material, and the shells of the BNC coaxial connector 32-2-2-4 and the BNC coaxial connector 32-2-2-5 are installed on the side of the metal shielding shell 32-2-2-1.

[0052] The oscilloscope 32-3 is used to receive the lightning current signal output by the controllable intensity lightning current source 1 extracted by the current sensor 32-1, and receive the piezoelectric signals of the upper electrode and the lower electrode of the piezoelectric sensor 32-2-2-3 in the shielded lightning impulse force piezoelectric measurement sensor unit 32-2-2 output by the BNC coaxial connector 32-2-2-4 and the BNC coaxial connector 32-2-2-5. The oscilloscope 32-3 collects and records the lightning current and piezoelectric signals and transmits them to the industrial control computer 32-4 respectively, and performs analysis, processing and result output of the lightning current signal and the lightning impulse force signal.

[0053] See also Figure 5 The control process of the full-waveform measuring device for the axial load of the lightning impact force of the carbon fiber composite laminate with a reliable transmission and wave-free reflection performance transmission structure of the present invention is: the lightning impact force test control unit 31PLC programmable controller 31-2 controls the charging voltage of the energy storage capacitor by the controllable high-voltage DC charging power supply 1-1 of the controllable intensity lightning current source 1 through the signal fed back by the charging voltage monitoring circuit 31-1; when the charging voltage rises to the preset impact voltage, the lightning impact force test control unit 31 controls the PLC programmable controller 31-2 to control the lightning current generating unit 1-2, so that the discharge switch is closed, and the pulse energy storage capacitor high-voltage discharge switch, waveform forming inductance and resistance perform lightning current discharge on the tested carbon fiber composite laminate 2; at the same time, start and set the measurement range of the digital oscilloscope 32-3 in advance, wait for the lightning current signal, record and transmit it to the industrial control computer 32-4. The lightning current parameters acting on the tested carbon fiber composite laminate 2 and the lightning impulse force formed by the lightning strike are respectively monitored by the digital oscilloscope 32-3. The signals collected by the current sensor 32-1 and the piezoelectric sensor 32-2-2-3 are sent to the industrial control computer 32-4. After processing and analysis, the law between the lightning impulse force borne by the tested carbon fiber composite laminate 2 and the parameters of the lightning current flowing through it is obtained. Ultrasonic C scanning is used to obtain the lightning fracture damage surface of the tested carbon fiber composite laminate under different lightning current amplitudes, and the relationship between the lightning impulse force and the lightning fracture damage is obtained.

[0054] The specific control and measurement process is as follows:

[0055] (1) Connect the controllable intensity lightning current source 1, the tested carbon fiber composite laminate 2, the carbon fiber composite lightning axial impact force loading and transfer measurement unit 32-2, the digital oscilloscope 32-3 and the industrial control computer 32-4 together as required;

[0056] (2) At least 5 lightning impulse current intensity points are selected, and the charging voltage at both ends of the energy storage capacitor of the controllable intensity lightning current source 1 is controlled by the PLC programmable controller 31-2 of the lightning impulse test control unit 31, so that the impulse intensity acting on the tested carbon fiber composite laminate 2 and the lightning impulse current flowing through the laminate reach different amplitudes;

[0057] (3) The industrial control computer 32-4 receives the lightning current signal measured by the current sensor 32-1 obtained from the digital oscilloscope 32-3. At the same time, the industrial control computer 32-4 receives the piezoelectric signal corresponding to the lightning current electrical parameters output by the piezoelectric sensor 32-2-2-3;

[0058] (4) The industrial control computer 32-4 processes and analyzes the received signal to obtain the axial lightning impulse force borne by the tested carbon fiber composite laminate 2 and the lightning current parameters acting on the tested carbon fiber composite laminate 2. The industrial control computer 32-4 analyzes and processes the signal to obtain the mathematical expression between the axial lightning impulse force and the lightning current parameters generated when the lightning current acts on the tested carbon fiber composite laminate 2;

[0059] (5) After the experiment on the relationship between axial lightning impulse force and lightning current parameters is completed, the carbon fiber composite laminate 2 is subjected to non-destructive testing methods such as ultrasonic scanning to obtain the lightning damage morphology, damage area, and damage depth of the carbon fiber composite laminate under different lightning current parameters, thereby obtaining the correlation mechanism between axial lightning impulse force and lightning damage of the carbon fiber composite laminate.

Claims

1. A full waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate, characterized by: It comprises a controllable intensity lightning current source (1), a tested carbon fiber composite laminate (2), and a lightning impulse force test control and measurement analysis unit (3); The controllable intensity lightning current source (1) is used to generate a lightning current shock wave, and comprises a controllable high-voltage direct current charging power source (1-1), a lightning current generating unit (1-2) and a charging voltage monitoring sensor (1-3); The tested carbon fiber composite material laminate (2) is connected to a lightning current generating unit (1-2) circuit; The lightning impulse test control and measurement analysis unit (3) comprises a lightning impulse test control unit (31) and a measurement analysis unit (32); the lightning impulse test control and measurement analysis unit (3) monitors and controls the operation of the controllable intensity lightning current source (1) through the control unit (31) and the measurement analysis unit (32); The lightning impulse force test control and measurement analysis unit (3) controls the controllable intensity lightning current source (1) to apply lightning impulse currents of different amplitudes to the tested carbon fiber composite laminate (2); and simultaneously receives the lightning current signal acting on the tested carbon fiber composite laminate (2) and the piezoelectric signal generated by the lightning impulse force borne by the tested carbon fiber composite laminate (2), and analyzes the lightning current and lightning impulse force signals to obtain the relationship between the lightning impulse force borne by the carbon fiber composite laminate (2) and the lightning current electrical parameters.

2. The full waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate according to claim 1 is characterized in that: The controllable high-voltage direct current charging power supply (1-1) adopts a voltage doubling charging method, the lightning current generating unit (1-2) is 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 loop, and the tested carbon fiber composite material laminate (2) and its clamping fixture are connected in series in the loop.

3. The full waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate according to claim 1 is characterized in that: The lightning impulse force test control unit (31) comprises a charging voltage monitoring circuit (31-1) and a PLC programmable controller (31-2); the lightning impulse force measurement and analysis unit (32) comprises a current sensor (32-1), a lightning axial impulse force loading and transfer measurement unit (32-2), a digital oscilloscope (32-3) and an industrial control computer (32-4); the current sensor (32-1) is sleeved on an electrical connection bus between the tested carbon fiber composite material laminate (2) and a controllable intensity lightning current source (1); The lightning axial impact force loading and transmission measurement unit (32-2) comprises a lightning impact force stress wave loading and transmission system (32-2-1) and a lightning impact force piezoelectric measurement sensor unit (32-2-2), which realizes the measurement of the full waveform of the lightning impact force of the carbon fiber composite material laminate (2); The oscilloscope (32-3) is used to receive the lightning current signal output by the controllable intensity lightning current source (1) extracted by the current sensor (32-1), and to receive the piezoelectric signal output by the lightning impulse force piezoelectric measurement sensor unit (32-2-2); the oscilloscope (32-3) collects and records the lightning current and piezoelectric signal and transmits them to the industrial control computer (32-4) respectively, and performs analysis, processing and result output of the lightning current signal and the lightning impulse force signal.

4. The full waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate according to claim 3 is characterized in that: The lightning impulse force stress wave loading and transmission system (32-2-1) comprises a supporting base plate (32-2-1-1), two test fixtures separately arranged on the supporting base plate (32-2-1-1), and the test fixtures comprise an insulating support block (32-2-1-2), a metal support strip or block (32-2-1-3) and a crimping strip or block (32-2-1-4) arranged in sequence from bottom to top; The carbon fiber composite laminate (2) under test is fixedly clamped by two metal support bars or blocks (32-2-1-3) and a crimping bar or block (32-2-1-4) of a test fixture through fastening bolts (32-2-1-5), and the lower surface of the carbon fiber composite laminate (2) under test is in contact with a shielded piezoelectric measurement sensor unit (32-2-2) containing a stress wave transmission system for lightning impulse force; the horizontal ends of the carbon fiber composite laminate (2) under test are connected to the low-voltage output port of a controllable intensity lightning current source (1) through the metal support bars or blocks (32-2-1-3) of the test fixture respectively; the lightning current flowing into the carbon fiber composite laminate (2) under test is injected from a metal rod-shaped electrode (32-2-1-6) arranged above the center thereof, and the distance between the metal rod-shaped electrode (32-2-1-6) and the upper surface of the carbon fiber composite laminate (2) under test can be adjusted.

5. The full waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate according to claim 3 is characterized in that: The shielded lightning impulse force piezoelectric measurement sensor unit (32-2-2) comprises a metal shielding shell (32-2-2-1), a stress wave transmission mechanism (32-2-2-2) and a piezoelectric sensor (32-2-2-3) arranged in the metal shielding shell (32-2-2-1); The stress wave transmission mechanism (32-2-2-2) comprises a transmission unit (32-2-2-2-1), a support unit (32-2-2-2-2), and an absorbing unit (32-2-2-2-3); the top end surface of the transmission unit (32-2-2-2-1) passes through the metal shielding shell (32-2-2-1) and is in close contact with the center of the lower surface of the tested carbon fiber composite material laminate (2), the lower end surface is in contact with the upper end surface of the support unit (32-2-2-2-2), and the lower end of the support unit (32-2-2-2-2) is fixed to the absorbing unit (32-2-2-2-3) arranged on the bottom surface of the metal shielding shell (32-2-2-1); the piezoelectric sensor (32-2-2-3) is installed between the lower surface of the transmission unit (32-2-2-2-1) and the upper surface of the support unit (32-2-2-2-2); A BNC coaxial connector (32-2-2-4) and a BNC coaxial connector (32-2-2-5) arranged on one side of the metal shielding shell (32-2-2-1) are electrically connected to an upper electrode and a lower electrode of a piezoelectric sensor (32-2-2-3) respectively; a shock wave formed by lightning acting on a tested carbon fiber composite laminate (2) is transmitted through a transmission unit (32-2-2-2-1) to form a uniformly distributed stress wave that squeezes the piezoelectric sensor (32-2-2-3), outputs a piezoelectric signal between an upper electrode and a lower electrode of the piezoelectric sensor (32-2-2-3), and transmits the piezoelectric signal to a digital oscilloscope (32-3) and an industrial control computer (32-4) in a lightning impulse force measurement and analysis unit (32) through a BNC coaxial connector (32-2-2-4) and a BNC coaxial connector (32-2-2-5).

6. The full waveform measuring device for axial load of lightning impact force of carbon fiber composite laminate according to claim 5 is characterized in that: The transmission unit (32-2-2-2-1) and the support unit (32-2-2-2-2) are insulating rods with circular or square cross-sections, and the length of the insulating rods is greater than or equal to 10 times the diameter or width of the cross-section; the absorbing unit (32-2-2-2-3) is an insulating plate with strong absorbing ability, and the piezoelectric sensor (32-2-2-3) is made of piezoelectric crystals, piezoelectric ceramics or piezoelectric film materials.

7. A full waveform measurement method for the axial load of a carbon fiber composite laminate lightning impact force based on the measuring device of claim 6, characterized in that The steps include: (1) connecting a controllable intensity lightning current source (1), a carbon fiber composite laminate to be tested (2), and a lightning impulse force test control and measurement analysis unit (3); (2) selecting no less than 5 lightning impulse current intensity points, and controlling the charging voltage at both ends of the energy storage capacitor of the controllable intensity lightning current source (1) through the PLC programmable controller (31-2) of the lightning impulse test control unit (31), so that the impulse intensity acting on the tested carbon fiber composite laminate (2) and the lightning impulse current flowing through the laminate reach different amplitudes; (3) The industrial control computer (32-4) receives the lightning current signal measured by the current sensor (32-1) obtained from the digital oscilloscope (32-3), and at the same time, the industrial control computer (32-4) receives the piezoelectric signal corresponding to the electrical parameters of the lightning current output by the piezoelectric sensor (32-2-2-3); (4) The industrial control computer (32-4) processes and analyzes the received signal to obtain the axial lightning impulse force borne by the tested carbon fiber composite laminate (2) and the electrical parameters of the lightning current acting on the tested carbon fiber composite laminate (2); and the industrial control computer (32-4) analyzes and processes to obtain the mathematical expression between the axial lightning impulse force generated when the lightning current acts on the tested carbon fiber composite laminate (2) and the lightning current parameters; (5) After the experiment on the relationship between axial lightning impulse force and lightning current parameters is completed, ultrasonic scanning is used to obtain the lightning damage morphology, damage area and damage depth of the tested carbon fiber composite laminates under different lightning current parameters, and the relationship between the axial lightning impulse force and the lightning damage of the tested carbon fiber composite laminates is obtained.

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