Carbon fiber composite laminated plate lightning impact force axial load full waveform measuring device and method

Abstract

The application discloses a lightning strike impact force axial load full waveform measuring device and method for carbon fiber composite laminated plates, and the axial load full waveform measuring device comprises a controllable intensity lightning current source, a test carbon fiber composite laminated plate and a lightning impact force test control and measurement analysis unit. The impact force acting on the upper side of the test carbon fiber composite laminated plate is transmitted to a piezoelectric sensor through a stress wave transmission mechanism transmission unit, so that the piezoelectric sensor obtains a signal generated by a real stress wave generated by lightning strike without reflection. By adjusting the amplitude of the lightning current output by the controllable intensity lightning current source, the mathematical analysis formula and the time response characteristic between the axial lightning impact force generated when the lightning current acts on the test material and the lightning current electrical parameter are obtained. The relationship between the lightning damage morphology and damage degree of the carbon fiber composite material and the axial lightning impact force is obtained, and theoretical support is provided for the research on the lightning damage mechanism of the test carbon fiber composite laminated plate.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of measuring the mechanical effect of lightning on materials, and relates to a lightning impact force axial load full waveform measuring device and method for a carbon fiber composite material laminated plate. BACKGROUND

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

[0003] In addition to arc heat and joule heat caused by large current, the direct effect of lightning on aircraft also includes complex mechanical effects. The Society of Automotive Engineers (SAE), the United States Military Standard (MIL STD), and the European Civil Aviation Organization (EUROCAE) have made detailed provisions for the test waveform and test method of the direct effect of lightning on aircraft and its components. At present, the experimental and simulation research on the lightning damage of carbon fiber composite materials explains the damage caused by resin pyrolysis and carbon fiber sublimation under the condition of lightning thermal effect. Related literature proves that the mechanical effect during lightning is not negligible, and the mechanical effect is divided into acoustic shock wave caused by arc channel expansion, electromagnetic force, and shock wave caused by surface explosion. Under the coupling effect of the axial component of lightning impact force and joule heat effect, the damage caused by lightning to the composite material structure will inevitably be aggravated. However, the current public literature cannot accurately and completely characterize it.

[0004] The invention patent CN 111609958 discloses a method for measuring the lightning impact force of carbon fiber composite materials, but the following deficiencies are found during the research:

[0005] (1) The test piezoelectric sensor is installed on the insulating plate fixed to the lower surface of the metal shielding shell. The stiffness of the insulating plate material affects the measurement accuracy of the response amplitude of the piezoelectric sensor to the lightning stress wave.

[0006] (2) The test piezoelectric sensor is placed between the impact force transmission rod with different materials and the insulating support plate above the metal shielding shell. The stress wave will be reflected when it is transmitted between different media. The transmission of stress wave between the transmission rod, support plate and shielding shell is complex, which affects the integrity and authenticity of the lightning wave signal measured by the piezoelectric sensor.

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

[0008] (4) In the study of the instantaneous relationship between lightning impact force and lightning current response time, the transmission time of lightning strike stress wave in the transmission rod is ignored, which causes the deviation of lightning current and impact force in phase, and has a certain influence on the study of lightning damage mechanism of carbon fiber composite material; in the long run, the deviation in measurement will also affect the design of lightning protection structure of carbon fiber composite material. SUMMARY

[0009] In view of the deficiencies of the prior art, the present application aims to provide a lightning impact force axial load full waveform measuring device for carbon fiber composite material laminated plate, to obtain the relationship between lightning impact force and lightning damage of the test carbon fiber composite material laminated plate, and to lay a foundation for the study of lightning damage mechanism of carbon fiber composite material and the design of lightning protection structure of composite material.

[0010] The present application is realized by the following technical solutions:

[0011] A lightning impact force axial load full waveform measuring device for carbon fiber composite material laminated plate, comprising a controllable intensity lightning current source, a test carbon fiber composite material laminated plate and a lightning impact force test control and measurement analysis unit.

[0012] The controllable intensity lightning current source is used to generate lightning current impact wave, and comprises a controllable high-voltage DC charging power source, a lightning current generating unit and a charging voltage monitoring sensor.

[0013] The test carbon fiber composite material laminated plate is connected in the loop of the lightning current generating unit.

[0014] The lightning impact force test control and measurement analysis unit comprises a lightning impact force test control unit and a measurement analysis unit; the lightning impact force test control and measurement analysis unit monitors and controls the operation of the controllable intensity lightning current source through the control unit and the measurement analysis unit.

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

[0016] Preferably, the controllable high-voltage DC charging power supply adopts a voltage multiplication charging mode, 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 test carbon fiber composite laminated plate and the clamping fixture are connected in series in the loop.

[0017] Preferably, the lightning impact force test control unit comprises a charging voltage monitoring circuit and a PLC programmable controller; the measurement and analysis unit of the lightning impact force comprises a current sensor, a lightning axial impact force loading and transmission measurement unit, a digital oscilloscope and an industrial control computer, and the current sensor is sleeved on the electrical connection bus of the test carbon fiber composite laminated plate and the controllable intensity lightning current source;

[0018] The lightning axial impact force loading and transmission measurement unit comprises a lightning impact force stress wave loading transmission system and a lightning impact force piezoelectric measurement sensor unit, and realizes the measurement of the full waveform of the lightning impact force of the carbon fiber composite laminated plate;

[0019] The oscilloscope is used for receiving the lightning current signal output by the controllable intensity lightning current source extracted by the current sensor and receiving the piezoelectric signal output by the lightning impact force piezoelectric measurement sensor unit; the oscilloscope transmits the collected and recorded lightning current and piezoelectric signals to the industrial control computer respectively, and analyzes, processes and outputs the results of the lightning current signal and the lightning impact force signal.

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

[0021] The test carbon fiber composite laminated plate is fixed and clamped by the metal support strip or block and the compression strip or block of the two test fixtures through fastening bolts, the lower surface of the test carbon fiber composite laminated plate is in contact with the lightning impact force piezoelectric measurement sensor unit containing the stress wave transmission system, and the horizontal two ends of the test carbon fiber composite laminated plate are connected with the low-voltage output port of the controllable intensity lightning current source through the metal support strip or block of each test fixture; the lightning current flowing into the test carbon fiber composite laminated plate is injected from the metal rod electrode arranged above the center of the test carbon fiber composite laminated plate, and the distance between the metal rod electrode and the upper surface of the test carbon fiber composite laminated plate can be adjusted.

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

[0023] The stress wave transmission mechanism comprises a transmission unit, a support unit and a wave absorbing unit; the top end surface of the transmission unit is in close contact with the center of the lower surface of the test carbon fiber composite laminated plate through the metal shielding shell, 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 with the wave absorbing unit arranged on the bottom surface of the metal shielding shell; and 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 one and the BNC coaxial connector two arranged on one side of the metal shielding shell are respectively electrically connected with the upper electrode and the lower electrode of the piezoelectric sensor; the shock wave formed by the lightning acting on the test carbon fiber composite laminated plate is transmitted through the transmission unit to form uniformly distributed stress waves to press the piezoelectric sensor, and the piezoelectric signal is output between the upper electrode and the lower electrode of the piezoelectric sensor and transmitted to the digital oscilloscope and the industrial control computer in the lightning impact force measurement and analysis unit through the BNC coaxial connector one and the BNC coaxial connector two.

[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 wave absorbing unit is an insulating plate with strong wave absorbing capacity, and the piezoelectric sensor is made of a piezoelectric crystal, a piezoelectric ceramic or a piezoelectric film material.

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

[0027] (1) connecting the controllable intensity lightning current source, the test carbon fiber composite laminated plate, the lightning impact force test control and measurement analysis unit together;

[0028] (2) selecting no less than 5 lightning impact current intensity points, and controlling the charging voltage between the energy storage capacitor of the controllable intensity lightning current source through the PLC programmable controller of the lightning impact force test control unit, so that the impact intensity acting on the test carbon fiber composite laminated plate and the lightning impact current flowing therethrough reach different amplitudes;

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

[0030] (4) the industrial control computer processes and analyzes the received signals to obtain the axial lightning impact force borne by the test carbon fiber composite laminated plate and the lightning current electrical parameter acting on the test carbon fiber composite laminated plate, and obtains the mathematical analytical expression between the axial lightning impact force generated when the lightning current acts on the test carbon fiber composite laminated plate and the lightning current parameter through the analysis and processing of the industrial control computer;

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

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

[0033] This invention provides a device and method for measuring the full waveform of axial lightning impact force on carbon fiber composite materials with a reliable transmission and wave-reflection-free transmission structure. The axial load full waveform measurement device includes a controllable intensity lightning current source, a carbon fiber composite laminate under test, and a lightning impact force test control and measurement analysis unit. The impact force acting on the carbon fiber composite laminate under test is transmitted to the piezoelectric sensor through a transmission unit with a length ten times the cross-sectional diameter in the stress wave transmission mechanism. Under the joint action of the support unit in the stress wave transmission mechanism, the piezoelectric sensor acquires the signal generated by the stress wave compression of the real lightning strike without reflection.

[0034] The piezoelectric sensing unit is designed with a metal shielding shell to suppress strong electromagnetic interference from the external lightning environment, ensuring that the measurement of the lightning impact force on the tested carbon fiber composite laminate is unaffected by 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 is measured through the piezoelectric sensing unit with electromagnetic shielding. This allows for a relatively accurate and complete measurement of the axial lightning impact force. Furthermore, by combining the transmission properties of the stress wave transmission mechanism, the time-phase relationship between the generated axial lightning impact force and the lightning current can be obtained.

[0035] Meanwhile, 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 impact force and the lightning current electrical parameters generated when the lightning current acts on the tested carbon fiber composite laminate were obtained. The relationship between the lightning damage morphology and damage degree of carbon fiber composite and the axial lightning impact force was obtained, providing theoretical support for the study of the lightning damage mechanism of the tested carbon fiber composite laminate.

[0036] A method for measuring the effect of lightning impact on carbon fiber composites, combined with non-destructive testing of carbon fiber composites, was developed to obtain the relationship between lightning impact force and lightning damage to the tested carbon fiber composite laminates. This lays the foundation for the study of lightning damage mechanisms of carbon fiber composites and the design of lightning protection structures for composite materials. Attached Figure Description

[0037] Figure 1 This is a block diagram of the device for measuring the axial load of the impact force of lightning strikes on carbon fiber composite laminates under strong electromagnetic interference, according to the present invention.

[0038] Figure 2 is the controllable intensity lightning current source schematic diagram of the full waveform measuring device of the impact force axial load of lightning strike on carbon fiber composite laminated plate under strong electromagnetic interference of the application;

[0039] Figure 3 is the lightning axial impact force loading and transmission measurement unit structure schematic diagram of the full waveform measuring device of the impact force axial load of lightning strike on carbon fiber composite laminated plate under strong electromagnetic interference of the application;

[0040] Figure 4 is the structure schematic diagram of the lightning impact force piezoelectric measurement sensing unit with shielding in the application;

[0041] Figure 5 is the flow chart of the full waveform measuring method of the impact force axial load of lightning strike on carbon fiber composite laminated plate under strong electromagnetic interference of the application. DETAILED DESCRIPTION

[0042] The application will be further described in detail below in combination with specific embodiments, which are the explanation of the application rather than limitation.

[0043] Referring to Figure 1 , the application has the full waveform measuring device of lightning impact force axial load of carbon fiber composite laminated plate with reliable transmission and wave reflection performance transmission structure, which comprises a controllable intensity lightning current source 1, a test carbon fiber composite laminated plate 2 and a lightning impact force test control and measurement analysis unit 3.

[0044] Referring to Figure 1 , the controllable intensity lightning current source 1 is used to generate lightning current impact wave, mainly comprising a controllable high-voltage direct-current charging power supply 1-1, a lightning current generating unit 1-2 and a charging voltage monitoring sensor 1-3.

[0045] Referring to Figure 1 , the lightning impact force test control and measurement analysis unit 3 comprises a lightning impact force test control unit 31 and a measurement analysis unit 32. The lightning impact force test control unit 31 mainly consists of a charging voltage monitoring circuit 31-1 and a PLC programmable controller 31-2, which can realize the flow control of composite material lightning impact force test; the measurement analysis unit 32 of lightning impact force mainly consists of a current sensor 32-1, a lightning axial impact force loading and transmission measurement unit 32-2, a digital oscilloscope 32-3 and an industrial control computer 32-4.

[0046] The lightning impulse force 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, and simultaneously receives the lightning current signal of the controllable intensity lightning current source 1 acting on the test carbon fiber composite material laminate 2 extracted by the current sensor 32-1, and the lightning impulse force borne by the test carbon fiber composite material 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 internal correlation between the lightning impulse force borne by the carbon fiber composite material laminate 2 and the lightning current electrical parameters.

[0047] Referring to Figure 2 The controllable high-voltage DC charging power supply 1-1 adopts a voltage doubling charging method to avoid the occurrence of corona discharge during discharging. The lightning current generation unit 1-2 mainly consists 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 test carbon fiber composite material laminate 2 and its clamping fixture are connected in series in the 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] Referring to Figure 3 The lightning axial impact force loading and transmission measurement unit 32-2 mainly includes a lightning impact force stress wave loading transmission 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 material laminate 2.

[0049] Referring to Figure 3 The lightning impact force stress wave loading transmission system 32-2-1 consists of a support bottom plate 32-2-1-1, an insulating support block 32-2-1-2, metal support strips or blocks 32-2-1-3 on both sides and crimping strips or blocks 32-2-1-4, fastening bolts 32-2-1-5 and metal rod electrodes 32-2-1-6. The test carbon fiber composite material laminate 2 is fixed and clamped by the metal support strips or blocks 32-2-1-3 and the crimping strips or blocks 32-2-1-4 on both sides of the fixture through the fastening bolts 32-2-1-5, and the horizontal ends are kept level. The lower surface of the test carbon fiber composite material laminate 2 is in contact with the lightning impact force piezoelectric measurement sensor unit 32-2-2 with a shielding stress wave transmission system. The horizontal ends of the test carbon fiber composite material laminate 2 are connected to the low-voltage output port of the controllable intensity lightning current source 1 through the respective metal support strips or blocks 32-2-1-3 on both sides of the test fixture. The lightning current flowing into the test carbon fiber composite material laminate 2 is injected from the metal rod electrode 32-2-1-6 above the center. The distance between the metal rod electrode 32-2-1-6 and the upper surface of the test carbon fiber composite material laminate 2 can be adjusted.

[0050] Referring to Figure 3 and Figure 4 , the lightning impulse force piezoelectric measurement sensor unit 32-2-2 includes a metal shield 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 one 32-2-2-4 and a BNC coaxial connector two 32-2-2-5. The piezoelectric sensor 32-2-2-3, the BNC coaxial connector one 32-2-2-4 and the BNC coaxial connector two 32-2-2-5 in the lightning impulse force piezoelectric measurement sensor unit 32-2-2 are at the same height, and the electrical connection between them ensures that the piezoelectric sensor 32-2-2-3 will not be deformed.

[0051] Referring to Figure 3 and Figure 4The stress wave transmission mechanism 32-2-2-2 in the lightning impact force piezoelectric measurement sensor unit 32-2-2-2 includes a transmission unit 32-2-2-2-1, a support unit 32-2-2-2-2, and a wave absorption 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 test carbon fiber composite laminate 2, and penetrates the metal shielding shell 32-2-2-1. The lower end surface is in contact with the upper end surface of the support unit 32-2-2-2-2 which is made of the same material and has the same size. The lower end of the support unit 32-2-2-2-2 is fixed to the wave absorption 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 one 32-2-2-4 and the BNC coaxial connector two 32-2-2-5 are arranged on one side of the piezoelectric sensor 32-2-2-3 and have the same height as the piezoelectric sensor 32-2-2-3. They are electrically connected to the upper electrode and the lower electrode of the piezoelectric sensor 32-2-2-3, respectively. The shock wave formed by the lightning acting on the test carbon fiber composite laminate 2 is transmitted through the transmission unit 32-2-2-2-1 in the stress wave transmission mechanism, forming a uniformly distributed stress wave, which presses the piezoelectric sensor 32-2-2-3. The piezoelectric signal is output between the upper electrode and the lower electrode of the piezoelectric sensor 32-2-2-3. The piezoelectric signal is transmitted to the digital oscilloscope 32-3 and the industrial control computer 32-4 in the lightning impact force measurement and analysis unit 32 through the BNC coaxial connector one 32-2-2-4 and the BNC coaxial connector two 32-2-2-5. The transmission unit 32-2-2-2-1 and the support unit 32-2-2-2-2 of the stress wave transmission mechanism 32-2-2-2 are insulating rods made of ceramic. The cross section of the insulating rod is circular or square. The length of the insulating rod is greater than or equal to 10 times the cross-sectional dimension. The wave absorption unit 32-2-2-2-3 is an insulating plate with strong wave absorption ability, made of epoxy plate. The piezoelectric sensor 32-2-2-3 is made of piezoelectric crystal, piezoelectric ceramic or piezoelectric film material. The housings of the BNC coaxial connector one 32-2-2-4 and the BNC coaxial connector two 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 to receive the piezoelectric signal of the upper electrode and the lower electrode of the piezoelectric sensor 32-2-2-3 in the lightning impact force piezoelectric measurement sensor unit 32-2-2-2 output by the BNC coaxial connector one 32-2-2-4 and the BNC coaxial connector two 32-2-2-5. The oscilloscope 32-3 collects and records the lightning current and piezoelectric signal, respectively, and transmits them to the industrial control computer 32-4 for analysis, processing and result output of the lightning current signal and the lightning impact force signal.

[0053] Referring to Figure 5 The control process of the lightning impact force axial load full waveform measuring device of the carbon fiber composite material laminated plate with reliable transmission and wave reflection performance transmission structure of the present application is as follows: the lightning impact force test control unit 31 PLC programmable controller 31-2 controls the controllable high-voltage DC charging power supply 1-1 of the controllable intensity lightning current source 1 through the feedback signal of the charging voltage monitoring circuit 31-1 to control the size of the charging voltage of the energy storage capacitor; when the charging voltage rises to the pre-set 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 to make the discharge switch closed, and the pulse energy storage capacitor high-voltage discharge switch, waveform forming inductor and resistance discharge lightning current to the test carbon fiber composite material laminated plate 2; at the same time, the measurement range of the digital oscilloscope 32-3 is started and set in advance, waiting for the lightning current signal, recording and transmitting it to the industrial control computer 32-4. The lightning current parameters acting on the test carbon fiber composite material laminated plate 2 and the lightning impact force formed by lightning are sent to the industrial control computer 32-4 after being collected by the digital oscilloscope 32-3 monitoring current sensor 32-1 and piezoelectric sensor 32-2-2-3, and the relationship between the lightning impact force and the lightning current parameters through the test carbon fiber composite material laminated plate 2 is obtained by processing and analysis. The lightning fracture damage surface of the test carbon fiber composite material laminated plate under different lightning current amplitudes is obtained by ultrasonic C scanning, and the relationship between lightning impact force and lightning fracture damage is obtained.

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

[0055] (1) The controllable intensity lightning current source 1, the test carbon fiber composite material laminated plate 2, the carbon fiber composite material lightning axial impact force loading and transmission measuring unit 32-2, the digital oscilloscope 32-3 and the industrial control computer 32-4 are connected together as required;

[0056] (2) At least 5 lightning impact current intensity points are selected, and the charging voltage across the energy storage capacitor of the controllable intensity lightning current source 1 is controlled by the PLC programmable controller 31-2 of the lightning impact force test control unit 31, so that the impact intensity acting on the test carbon fiber composite material laminated plate 2 and the lightning impact current flowing through it reach different amplitudes;

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

[0058] (4) the industrial control computer 32-4 processes and analyzes the received signals to obtain the axial lightning impact force borne by the test carbon fiber composite material laminate 2 and the lightning current electrical parameters acting on the test carbon fiber composite material laminate 2, and the mathematical analytical expression between the axial lightning impact force generated when the lightning current acts on the test carbon fiber composite material laminate 2 and the lightning current parameters is obtained through analysis and processing of the industrial control computer 32-4;

[0059] (5) after the experiment of the relationship between the axial lightning impact force and the lightning current parameters is completed, the lightning damage morphology, damage area and damage depth of the test carbon fiber composite material laminate under different lightning current parameters are obtained by using non-destructive testing methods such as ultrasonic scanning on the test carbon fiber composite material laminate 2, and thus the correlation mechanism between the axial lightning impact force and the lightning damage of the test carbon fiber composite material laminate is obtained.

Claims

1. A lightning strike impact force axial load full waveform measuring device for carbon fiber composite laminates, characterized by: It comprises a controllable intensity lightning current source (1), a test carbon fiber composite material laminate (2) and a lightning impact force test control and measurement analysis unit (3). The controllable intensity lightning current source (1) is used for generating lightning current impact wave, comprising 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). The test carbon fiber composite material laminate (2) is connected in the loop of the lightning current generating unit (1-2). The lightning impact force test control and measurement analysis unit (3) comprises a lightning impact force test control unit (31) and a measurement analysis unit (32); the lightning impact force test control and measurement analysis unit (3) monitors and controls the operation of the controllable intensity lightning current source (1) through the lightning impact force test control unit (31) and the measurement analysis unit (32). The lightning impact force test control and measurement analysis unit (3) controls the controllable intensity lightning current source (1) to apply lightning impact current with different amplitudes to the test carbon fiber composite material laminate (2); simultaneously receives the lightning current signal acting on the test carbon fiber composite material laminate (2) and the piezoelectric signal generated by the lightning impact force borne by the test carbon fiber composite material laminate (2), and analyzes the lightning current and lightning impact force signals to obtain the relationship between the lightning impact force borne by the carbon fiber composite material laminate (2) and the lightning current electrical parameters. The lightning impact force test control unit (31) comprises a charging voltage monitoring circuit (31-1) and a PLC programmable controller (31-2); the lightning impact force measurement analysis unit (32) comprises a current sensor (32-1), a lightning axial impact force loading and transmission measurement unit (32-2), a digital oscilloscope (32-3) and an industrial control computer (32-4), and the current sensor (32-1) is sleeved on the electrical connection bus of the test carbon fiber composite material laminate (2) and the 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 transmission system (32-2-1) and a lightning impact force piezoelectric measurement sensing unit (32-2-2), and realizes the measurement of the lightning impact force full waveform of the carbon fiber composite material laminate (2); The oscilloscope (32-3) is used for receiving the lightning current signal output by the controllable intensity lightning current source (1) extracted by the current sensor (32-1) and receiving the piezoelectric signal output by the lightning impact force piezoelectric measurement sensing unit (32-2-2); the oscilloscope (32-3) transmits the collected and recorded lightning current and piezoelectric signals to the industrial control computer (32-4) respectively, and analyzes, processes and outputs the results of the lightning current signal and the lightning impact force signal; The lightning impact force piezoelectric measurement sensing 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 a suction 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 test carbon fiber composite laminated plate (2) through the metal shielding shell (32-2-2-1), 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 with the suction 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); The BNC coaxial connector one (32-2-2-4) and the BNC coaxial connector two (32-2-2-5) arranged on one side of the metal shielding shell (32-2-2-1) are respectively electrically connected with the upper electrode and the lower electrode of the piezoelectric sensor (32-2-2-3); the shock wave formed by the lightning acting on the test carbon fiber composite laminated plate (2) is transmitted through the transmission unit (32-2-2-2-1) to form uniformly distributed stress waves to press the piezoelectric sensor (32-2-2-3), and the piezoelectric signal is output between the upper electrode and the lower electrode of the piezoelectric sensor (32-2-2-3), and is transmitted to the digital oscilloscope (32-3) and the industrial control computer (32-4) in the lightning impact force measurement and analysis unit (32) through the BNC coaxial connector one (32-2-2-4) and the BNC coaxial connector two (32-2-2-5).

2. The carbon fiber composite laminates lightning strike impact force axial load full waveform measuring device according to claim 1, characterized in that: The controllable high-voltage DC charging power supply (1-1) adopts a voltage doubling charging mode, the lightning current generation 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, and the test carbon fiber composite laminated plate (2) and its clamping fixture are connected in series in the circuit.

3. The carbon fiber composite laminates lightning strike impact force axial load full waveform measuring device of claim 1, wherein: The lightning impact force stress wave loading transmission system (32-2-1) comprises a support bottom plate (32-2-1-1), two test clamps arranged separately on the support bottom plate (32-2-1-1), and the test clamps comprise, from bottom to top, an insulating support block (32-2-1-2), a metal support strip or block (32-2-1-3) and a compression strip or block (32-2-1-4); The test carbon fiber composite laminated plate (2) is clamped and fixed by the metal supporting strips or blocks (32-2-1-3) and the pressing strips or blocks (32-2-1-4) of the two test clamps through the fastening bolts (32-2-1-5), the lower surface of the test carbon fiber composite laminated plate (2) is in contact with the lightning impact force piezoelectric measurement sensor unit (32-2-2), the horizontal two ends of the test carbon fiber composite laminated plate (2) are connected with the low-voltage output port of the controllable intensity lightning current source (1) through the respective metal supporting strips or blocks (32-2-1-3) of the test clamps, the lightning current flowing into the test carbon fiber composite laminated plate (2) is injected from the metal rod electrode (32-2-1-6) arranged above the center of the test carbon fiber composite laminated plate (2), and the distance between the metal rod electrode (32-2-1-6) and the upper surface of the test carbon fiber composite laminated plate (2) can be adjusted.

4. The carbon fiber composite laminates lightning strike impact force axial load full waveform measuring device of claim 1, wherein: The transmission unit (32-2-2-2-1) and the supporting unit (32-2-2-2-2) are insulating rods with circular or square cross sections, and the length of the insulating rod is greater than or equal to 10 times the diameter or width of the cross section; the adsorbing unit (32-2-2-2-3) is an insulating plate with strong wave-absorbing capacity, and the piezoelectric sensor (32-2-2-3) is made of a piezoelectric crystal, a piezoelectric ceramic or a piezoelectric film material.

5. The measurement method of lightning strike impact force axial load full waveform of the carbon fiber composite material laminated plate of the measuring device according to claim 4, characterized in that The method comprises the following steps: (1) connecting the controllable intensity lightning current source (1), the test carbon fiber composite laminated plate (2) and the lightning impact force test control and measurement analysis unit (3) together; (2) selecting no less than 5 lightning impact current intensity points, controlling the charging voltage between the energy storage capacitor of the controllable intensity lightning current source (1) through the PLC programmable controller (31-2) of the lightning impact force test control unit (31), so that the impact intensity acting on the test carbon fiber composite laminated plate (2) and the lightning impact current flowing therethrough 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), at the same time, the industrial control computer (32-4) receives the piezoelectric signal corresponding to the lightning current electrical parameter output by the piezoelectric sensor (32-2-2-3); (4) the industrial control computer (32-4) processes and analyzes the received signals to obtain the axial lightning impact force borne by the test carbon fiber composite laminated plate (2) and the lightning current electrical parameter acting on the test carbon fiber composite laminated plate (2), and the mathematical analytical expression between the axial lightning impact force generated when the lightning current acts on the test carbon fiber composite laminated plate (2) and the lightning current parameter is obtained through the analysis and processing of the industrial control computer (32-4); (5) after the experiment of the relationship between the axial lightning impact force and the lightning current parameter is completed, the lightning damage morphology, damage area and damage depth of the test carbon fiber composite laminated plate under different lightning current parameters are obtained by ultrasonic scanning of the test carbon fiber composite laminated plate (2), and the relationship between the axial lightning impact force and the lightning damage of the test carbon fiber composite laminated plate is obtained.

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