Device and method for monitoring the integrity of small-sized metal samples under high pressure.

Abstract

This invention discloses a device and method for monitoring the integrity of small-sized metal samples under high pressure, comprising: an autoclave; an environmental control system; a loading system including an electronic testing machine and a connecting rod, wherein the electronic testing machine loads a small-sized metal sample installed in the autoclave in an electrically insulated manner via the connecting rod, achieving controlled stress or strain loading; and an electrical signal measurement system including a constant current source, a current reversing device, and a signal acquisition device; wherein the constant current source applies a constant current to the small-sized metal sample, the current reversing device switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value across the small-sized metal sample; and the change in the integrity of the small-sized metal sample is determined based on the change in voltage value during the loading process. This invention enables online monitoring of the integrity of small-sized metal samples under high pressure.

Description

Technical Field

[0001] This invention belongs to the field of performance evaluation of high-end equipment materials, and particularly relates to a device and method for monitoring the integrity of small-sized metal samples under high pressure. Background Technology

[0002] In some industrial sectors, equipment operates under extremely harsh environments with high-pressure fluids for extended periods. Examples include the high-temperature, high-pressure water and gaseous environments of nuclear power plants, the low-temperature, high-pressure seawater environments of deep-sea equipment, and the high-pressure gaseous hydrogen environments of hydrogen transportation and storage facilities. When metallic structural materials operate in such environments, they are highly susceptible to the combined effects of loads and corrosion, leading to gradual performance degradation and even failure. Therefore, both industry and academia have long emphasized laboratory research to reveal the aging and failure patterns of materials, ensuring the structural integrity and safety of critical equipment during service.

[0003] In relevant experiments, accurately assessing the integrity of experimental samples is crucial for improving experimental efficiency and the reliability of conclusions. For large-sized metal samples, deformation or failure can usually be directly monitored using devices such as displacement extensometers or force sensors. However, for small-sized metal samples, due to their minute deformation, low load-bearing capacity, and limited damage area, existing sensors struggle to effectively capture changes in their condition. Currently, the only option is to periodically pause the experiment, remove the sample, and conduct multi-scale inspections using the naked eye or microscope to determine the presence of cracks or fractures, thus confirming its integrity. This process is not only cumbersome and inefficient but also disrupts the continuity of the experiment. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides an integrity monitoring device and method for small-sized metal samples under high pressure, which realizes online monitoring of the integrity of small-sized metal samples under high pressure.

[0005] This application provides an integrity monitoring device for small-sized metal samples under high pressure, an autoclave, which achieves high pressure environment sealing through a sealing structure and is used to contain small-sized metal samples;

[0006] An environmental control system, connected to the autoclave, is used to regulate the environmental parameters of the autoclave.

[0007] The loading system includes an electronic testing machine and a connecting rod. The electronic testing machine loads a small-sized metal sample installed in the autoclave in an electrically insulated manner through the connecting rod, thereby achieving controlled loading of stress or strain.

[0008] An electrical signal measurement system includes a constant current source, a current commutation device, and a signal acquisition device. The constant current source applies a constant current to the small-sized metal sample, the current commutation device switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value across the small-sized metal sample. The system determines the integrity change of the small-sized metal sample based on the change in voltage value during the loading process.

[0009] In some embodiments, the signal acquisition device includes a multi-channel signal analyzer, a voltmeter, and wires; the wires are respectively connected to both ends of a small-sized metal sample; the multi-channel signal analyzer is used to synchronously record voltage signals, load displacement signals, and environmental parameters.

[0010] In some embodiments, the frequency at which the current switching device switches the current direction is 0.1 to 10 Hz.

[0011] In some embodiments, the loading system is further provided with a clamping device, and the small-sized metal sample is electrically insulated from the clamping device by an insulating component.

[0012] In some embodiments, the wire is soldered to the small-sized metal sample.

[0013] Secondly, this invention discloses a method for monitoring the integrity of small-sized metal samples under high pressure, and the device for monitoring the integrity of small-sized metal samples under high pressure as described above includes:

[0014] The small-sized metal sample was fixed inside the autoclave and the autoclave was closed.

[0015] The environmental control system injects the medium, regulates the environmental parameters to a preset range, and maintains the stability of the medium composition.

[0016] A controlled loading system is used to apply a load to a small metal sample; a constant current source is used to apply a constant current and a current reversing device switches the current direction at a preset frequency; and a signal acquisition device intermittently monitors the voltage value across the small metal sample.

[0017] The integrity changes of the small-sized metal sample are determined based on the changes in voltage values ​​during the test.

[0018] In some implementations, determining the integrity change of the small-sized metal sample based on changes in voltage during testing includes:

[0019] Record the initial voltage value and compare the real-time voltage value with the initial voltage value; the initial voltage value is the voltage signal when the small-sized metal sample is intact.

[0020] During the test, the loading system performs voltage measurements and continuously collects real-time voltage values, comparing them with the initial voltage value; and the loading system pauses loading each time a voltage value is measured.

[0021] When the real-time voltage value deviates from the average value and exceeds the standard deviation threshold, the integrity of the small-sized metal sample changes. Record the corresponding loading conditions and environmental parameters.

[0022] In some implementations, the frequency at which the current reversing device switches the current direction is determined based on the connection point between the wire and the small-sized metal sample, and the preset frequency is 0.1~10Hz.

[0023] In some implementations, the standard deviation threshold includes a first threshold and a second threshold: when the real-time voltage value deviates from the initial average value by more than the first threshold but not more than the second threshold, the small-sized metal sample undergoes partial fracture; when the real-time voltage value deviates from the initial average value by more than the second threshold, the small-sized metal sample undergoes complete fracture.

[0024] In some implementations, the first threshold is 3 to 5 times the standard deviation of the initial voltage value, and the second threshold is 10 to 100 times the standard deviation of the initial voltage value.

[0025] This application provides a device and method for monitoring the integrity of small-sized metal samples under high pressure. By applying a constant current to the small-sized metal sample under high pressure and switching the current direction at a preset frequency using a current reversing device, the voltage across the small-sized metal sample is intermittently measured by a signal acquisition device. This effectively avoids interference from contact resistance and changes in the dielectric environment on the measurement results. By comparing the changes in voltage during the loading process, it is possible to accurately determine whether the integrity of the small-sized metal sample has changed without disrupting the continuity of the experiment. This online monitoring reduces the frequent operations required for traditional downtime sampling and inspection, improves experimental efficiency, and ensures the continuity and reliability of the data. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the integrity monitoring device for small-sized metal samples under high pressure provided by the present invention;

[0027] Figure 2 This is a flowchart illustrating the integrity monitoring method for small-sized metal samples under high pressure provided by the present invention.

[0028] Figure 3 The simulation results are based on an alloy sheet sample with a length of 30 mm, a width of 2 mm, and a thickness of 0.2 mm.

[0029] Figure 4 and Figure 5The test results are based on an alloy sheet sample with a length of 30 mm, a width of 2 mm, and a thickness of 0.2 mm.

[0030] In the diagram: 1. Autoclave; 2. Electronic testing machine; 3. Connecting rod; 4. Environmental control system; 5. High-pressure pump; 6. Back pressure valve; 7. Constant current source; 8. Voltmeter; 9. Current reversing device; 10. Multichannel signal instrument; 11. Processor; 12. Small-sized metal sample. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specifically stated, the relative arrangement, expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0032] This application provides an integrity monitoring device for small-sized metal samples 12 under high pressure, enabling online monitoring of the integrity of small-sized metal samples 12 under high pressure.

[0033] Specifically, such as Figure 1 The diagram shows the structure of the integrity monitoring device for a small-sized metal sample 12 under high pressure. It includes a high-pressure autoclave 1, an environmental control system 4, a loading system, and an electrical signal measurement system. The high-pressure environment is sealed through a sealing structure to accommodate the small-sized metal sample 12.

[0034] Environmental control system 4 is connected to autoclave 1 and is used to regulate the environmental parameters of autoclave 1.

[0035] The loading system includes an electronic testing machine 2 and a connecting rod 3. The electronic testing machine 2 loads a small-sized metal sample 12 that is electrically insulated and installed in the autoclave 1 through the connecting rod 3, thereby achieving controlled loading of stress or strain.

[0036] An electrical signal measurement system includes a constant current source 7, a current commutation device 9, and a signal acquisition device. The constant current source applies a constant current to the small-sized metal sample 12, the current commutation device 9 switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value across the small-sized metal sample 12. The system determines the integrity change of the small-sized metal sample 12 based on the change in voltage value during the loading process.

[0037] It is worth noting that the small-sized metal sample 12 used, hereinafter referred to as the sample, refers to a metal sample in which the load borne by the sample during loading is not significantly greater than the frictional force of the loading link 3, and the loading starting point cannot be determined by traditional force values. These generally include thin metal sheets or micro rods, with forces below tens of Newtons. The integrity of the small-sized metal sample 12 refers to its ability to maintain its original structural state under loading and high-pressure environments. Changes in integrity mean that the small-sized metal sample 12 is considered to be in an intact state when no structural damage such as cracks or fractures occurs during the entire experiment; when local crack propagation or partial fracture occurs, but there are still incompletely separated load-bearing areas, it is considered to be in a partially fractured state; and when the sample completely fractures or loses its continuity and can no longer bear the load, it is considered to be in a completely fractured state.

[0038] The autoclave 1 is made of an alloy material with excellent corrosion resistance, preferably stainless steel or a nickel-based alloy. In actual experiments, the material selection and sealing structure can be determined according to the specific test medium and temperature and pressure requirements. In practical applications, the autoclave can be designed according to the actual purpose, and no specific limitations are made in this application.

[0039] To adapt to various harsh operating conditions, such as the high-temperature and high-pressure water environment of nuclear power plants, the low-temperature and high-pressure seawater environment of deep seas, and the high-pressure gaseous hydrogen environment for hydrogen transportation and storage, the pressure resistance of the autoclave 1 can be designed from 30MPa to 100MPa, and the temperature resistance range can reach -50℃ to 700℃, and can be expanded accordingly according to experimental needs. The autoclave 1 is equipped with a medium inlet and outlet, a pressure detection port, and a temperature sensing port, which can achieve fluid circulation, pressure regulation, and temperature control with the external environmental control system 4, ensuring the long-term stability of the composition and physical parameters of the medium inside the autoclave. At the same time, the autoclave structure has been verified by finite element strength, which can withstand the internal pressure load under the action of high-pressure fluid and ensure that no plastic deformation or sealing failure occurs under multiple cyclic loading, thereby providing a stable and repeatable high-pressure test environment for the integrity monitoring of small-sized metal samples 12.

[0040] The environmental control system 4 is connected to the autoclave 1 and is used to regulate the environmental parameters of the autoclave 1, enabling it to simulate various testing environments such as the high-temperature and high-pressure water environment of nuclear power plants, the high-temperature and high-pressure gaseous environment of nuclear power plants, the low-temperature and high-pressure seawater environment of deep seas, and high-pressure hydrogen. The environmental control system 4 includes functional modules such as a high-pressure pump 5, a back pressure valve 6, and a heating jacket or heat exchanger. The medium can be selected as a water-based solution or an inert gas according to experimental needs. Specific control parameters include the solute concentration, dissolved gas content, pH value, conductivity, or the component ratio in the gaseous medium. The high-pressure pump 5 injects the test medium into the autoclave 1 and provides a continuous pressure input. The back pressure valve 6 regulates and maintains the target pressure inside the autoclave to meet the simulation requirements of the load-corrosion coupled environment under specific working conditions. The heating jacket or heat exchanger installed on the outer wall of the autoclave 1 heats or cools the medium, stabilizing the test temperature within a set range, such as from room temperature to a high-temperature environment of 300°C, or simulating a low-temperature environment.

[0041] When the test medium is an aqueous solution, the environmental control system 4 adjusts the solute concentration, dissolved gas content, pH value, and conductivity. When the test medium is a gas, the environmental control system 4 regulates and stabilizes the gas component ratio. During long-term loading tests, the environmental control system 4 can dynamically adjust and monitor the medium composition and physical parameters in real time, thereby ensuring that the internal environment of the autoclave 1 is always maintained within the preset range, meeting the experimental requirements for integrity monitoring of small-sized metal samples 12, while avoiding interference from fluctuations in the test environment on the integrity monitoring results, and improving the accuracy and comparability of experimental data.

[0042] The loading system includes an electronic testing machine 2 and a connecting rod 3. The electronic testing machine 2 loads a small-sized metal sample 12, which is electrically insulated and installed inside the autoclave 1, via the connecting rod 3. This system applies controlled stress or strain to the small-sized metal sample 12 under high pressure. The electronic testing machine 2 is located outside the autoclave 1, and its loading end is connected to the connecting rod 3. The connecting rod 3 passes through the lid of the autoclave 1 and extends into the autoclave, transmitting the loading force or displacement output by the electronic testing machine 2 to the small-sized metal sample 12. To avoid electrical signal interference, the loading system also includes a clamping device. The small-sized metal sample is electrically insulated from the clamping device by an insulating component. The insulating component between the connecting rod 3 and the small-sized metal sample 12 is electrically isolated from the autoclave 1 and the connecting rod 3, ensuring that current only flows through the sample to form a circuit, thereby ensuring the accuracy of electrical signal measurement.

[0043] During the loading process, the electronic testing machine 2 controls the linkage 3 to apply constant strain rate loading, stepped loading, or cyclic loading to the small-sized metal sample 12 according to the preset loading path. Its loading accuracy can reach the control level of micron-level displacement or Newton-level load. The loading system and the electrical signal measurement system are independent of each other. Through electrical insulation design, interference with electrical signal acquisition during the loading process is effectively avoided, thereby improving the reliability of subsequent integrity monitoring.

[0044] An electrical signal measurement system is used to monitor the integrity changes of a small-sized metal sample 12 in real time or intermittently during loading. The system includes a constant current source 7, a current commutation device 9, and a signal acquisition device. The constant current source applies a constant current to the small-sized metal sample 12, the current commutation device 9 switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value across the small-sized metal sample 12. The integrity changes of the small-sized metal sample 12 are determined based on the changes in the voltage value during loading.

[0045] The signal acquisition device includes a multi-channel signal analyzer 10, a voltmeter 8, and connecting wires. The connecting wires connect the two ends of the small-sized metal sample 12 along its length to the voltmeter 8. The multi-channel signal analyzer is used to synchronously record voltage values, load displacement signals, and environmental parameters. A constant current source 7 provides a stable and constant DC current, which flows through the small-sized metal sample 12 via the connecting wires. The voltmeter 8 is used to measure the voltage values ​​and minute changes across the metal sample, and transmits the voltage values ​​to the multi-channel signal analyzer 10 and to the processor 11 for recording and processing. A current reversing device 9 can switch the current direction at a frequency of 0.1~10Hz to eliminate the influence of contact resistance heating on the stability of the voltage signal, making the measurement results more accurate and reliable. In this application, the current reversing device 9, based on the influence of the connection between the connecting wires and the small-sized metal sample 12, including factors such as material type and connection method, generally selects a frequency of about 1Hz in practical applications to prevent contact resistance heating from interfering with local voltage changes. The voltmeter 8 can be a nanovoltmeter to monitor minute voltage changes when the sample is partially broken.

[0046] In practice, such as Figure 2 As shown, the following integrity monitoring method is adopted:

[0047] Step S1: Fix the small-sized metal sample 12 inside the autoclave 1 and close the autoclave 1;

[0048] Step S2: Inject the medium through the environmental control system 4, adjust the environmental parameters to the preset range, and maintain the stability of the medium composition;

[0049] Step S3: Apply controlled loading to the small-sized metal sample 12 through the loading system; apply a constant current through the constant current source 7 and switch the current direction at a preset frequency using the current switching device; and intermittently monitor the voltage value across the small-sized metal sample 12 using the signal acquisition device.

[0050] Step S4: Determine the integrity change of the small-sized metal sample 12 based on the change in voltage value during the test.

[0051] To ensure the sensitivity of electrical signal detection, the sample is electrically insulated and mounted inside the autoclave 1, ensuring that current flows only through the sample to form a circuit and not through the metal components of the autoclave 1 or the loading system. A controlled load is applied to the sample using the loading system, and the signal acquisition device pauses loading during each voltage measurement to avoid introducing noise that could interfere with the electrical signal acquisition during the test. During the test, stress is applied through the loading system, and voltage values ​​are acquired.

[0052] The integrity changes of the small-sized metal sample 12 are determined based on the changes in voltage values ​​during the test, including:

[0053] Step S41: Record the initial voltage value and compare the real-time voltage value with the initial voltage value; the initial voltage value is the voltage signal when the small-sized metal sample 12 is intact;

[0054] Step S42: During the test, load the system to measure voltage and continuously collect real-time voltage values, comparing them with the initial voltage value; and each time the voltage value is measured, the loading system pauses loading.

[0055] Step S43: When the real-time voltage value deviates from the average value and exceeds the standard deviation threshold, it is determined that the integrity of the small-sized metal sample 12 has changed, and the corresponding loading conditions and environmental parameters are recorded.

[0056] Before the test, the initial voltage value of the small-sized metal sample 12 in its intact state was first recorded, and the distribution characteristics of the initial voltage value, including the mean and standard deviation, were statistically analyzed. The initial voltage value is the voltage signal of the small-sized metal sample 12 when it is intact. During the loading test, the signal acquisition device intermittently measured the voltage values ​​across the sample and compared them with the initial voltage value distribution characteristics. When the voltage value deviates significantly from the initial value over a continuous period, the integrity of the sample is considered to have changed.

[0057] During the test, stress or strain is applied according to a preset loading path using a loading system, while the electrical signal measurement system continuously acquires the real-time voltage values ​​across the small-sized metal sample 12. The loading system pauses loading each time a real-time voltage value is measured to avoid mechanical noise introduced by the loading interfering with the voltage signal measurement. The real-time voltage value is compared with the initial voltage value to determine the sample integrity status.

[0058] When the real-time voltage value deviates from the average value, its integrity has changed; the greater the deviation, the higher the degree of damage. The standard deviation threshold includes a first threshold and a second threshold. When the real-time voltage value deviates from the initial average value by more than the first threshold but not more than the second threshold, the small-sized metal sample 12 is determined to have partially fractured; when the real-time voltage value deviates from the initial average value by more than the second threshold, the small-sized metal sample 12 is determined to have completely fractured. The first threshold is 3 to 5 times the standard deviation of the initial voltage signal, and the second threshold is 10 to 100 times the standard deviation of the initial voltage signal. By using the standard deviation threshold judgment standard, it is possible to sensitively distinguish whether the small-sized metal sample 12 is in an intact, partially fractured, or completely fractured state, and by combining this with the loading conditions and environmental parameters at the time of loading, the entire process of changes in the sample's structural integrity can be accurately captured.

[0059] The standard deviation threshold is affected by the sample material, size, and conductivity of the medium within the autoclave. It should be noted that the conductivity of the medium has a certain impact on the degree of signal change. When the medium has good conductivity, even if cracks or gaps appear in the sample, the medium may still conduct the cracks and gaps, resulting in a smaller change in the voltage signal. However, when the medium has poor conductivity or is non-conductive, once the sample cracks, the circuit is blocked, leading to a more significant change in the voltage signal. Therefore, this invention can determine the integrity status of small-sized metal samples 12 by combining the degree of voltage signal deviation, and further distinguish whether the sample is in an intact, partially broken, or completely broken state by combining the deviation range, thereby achieving sensitive monitoring of sample integrity under high pressure.

[0060] Figure 3 To obtain the results using the finite element method (FEM), an alloy sample of 316 stainless steel with a length of 30 mm, a width of 2 mm, and a thickness of 0.2 mm was placed in water. A constant current of 0.1 A was applied to both ends of the sample along its length. A crack was set at the center of the sample along the width direction and extending through the thickness direction. The crack width was 0.1 mm, and the depth ranged from 0 to 2 mm, where 0 mm corresponds to no crack and 2 mm corresponds to complete fracture. The voltage drop across the sample along its length was calculated. The simulation results show that as the crack depth increases, the voltage signal first rises slowly and then rises sharply. This indicates that when the sample is partially fractured, the voltage signal is higher than that of the intact sample, but the increase is limited. However, when the sample is completely fractured, the voltage signal increases by several orders of magnitude.

[0061] The same alloy samples were used for testing, such as Figure 4As shown, the voltage signal fluctuated during the experiment, with the dashed line representing the initial signal average deviation from 5 times the standard deviation. The signal did not deviate significantly during days 0-19, corresponding to the intact state of the sample. On day 24, the signal deviated significantly, corresponding to partial sample breakage. Upon completion of the experiment and removal of the sample, partial breakage was confirmed. Figure 5 This is a schematic diagram of voltage value recording from another experiment. The dashed lines represent the initial signal average value deviating from the standard deviation by 5 times. The smaller images are magnified local portions. During days 0-2, the voltage values ​​did not deviate significantly, corresponding to intact samples. On day 3, the voltage values ​​deviated significantly, increasing by more than two orders of magnitude compared to the initial voltage value, corresponding to complete sample breakage. After the experiment ended and the sample was removed, it was confirmed to be completely broken.

[0062] This invention enables sensitive and reliable online monitoring of the integrity of small-sized metal samples 12 under high-pressure conditions. By recording the initial voltage value when the sample is intact and continuously comparing the real-time voltage value with the initial value during the test, minute changes in the sample's structural state can be captured in a timely manner. The loading system pauses loading during voltage measurement, effectively avoiding noise interference introduced during the loading process, thereby ensuring the stability and accuracy of electrical signal acquisition. By setting a standard deviation threshold, the invention can distinguish between three states of the sample: intact, partially fractured, and completely fractured, and the degree of deviation can quantitatively reflect the degree of damage development. Compared with traditional methods that rely on periodic shutdowns for inspection, this scheme can obtain continuous and complete state data without interrupting the experiment, significantly improving experimental efficiency.

[0063] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for monitoring the integrity of small-sized metal samples under high pressure, characterized in that, It is used in an integrity monitoring device, the integrity monitoring device comprising: An autoclave, through a sealing structure, achieves a high-pressure environment seal and is used to contain small-sized metal samples; An environmental control system, connected to the autoclave, is used to regulate the environmental parameters of the autoclave. The loading system includes an electronic testing machine and a connecting rod. The electronic testing machine loads a small-sized metal sample installed in the autoclave in an electrically insulated manner through the connecting rod, thereby achieving controlled loading of stress or strain. An electrical signal measurement system includes a constant current source, a current commutation device, and a signal acquisition device. The constant current source applies a constant current to the small-sized metal sample, the current commutation device switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value across the small-sized metal sample. The system determines the change in the integrity of the small-sized metal sample based on the change in voltage value during the loading process. The method includes: The small-sized metal sample was fixed inside the autoclave and the autoclave was closed. The environmental control system injects the medium, regulates the environmental parameters to a preset range, and maintains the stability of the medium composition. A controlled loading system is used to apply a load to a small metal sample; a constant current source is used to apply a constant current and a current commutation device switches the current direction at a preset frequency; a signal acquisition device intermittently monitors the voltage value across the small metal sample; the frequency at which the current commutation device switches the current direction is determined based on the connection point between the wire and the small metal sample. The integrity changes of the small-sized metal sample are determined based on the voltage changes during the test, including: Record the initial voltage value and compare the real-time voltage value with the initial voltage value; the initial voltage value is the voltage signal when the small-sized metal sample is intact. During the test, the loading system performs voltage measurements and continuously collects real-time voltage values, comparing them with the initial voltage value; and the loading system pauses loading each time a voltage value is measured. When the real-time voltage value deviates from the average value and exceeds the standard deviation threshold, the integrity of the small-sized metal sample changes. Record the corresponding loading conditions and environmental parameters.

2. The method for monitoring the integrity of small-sized metal samples under high pressure according to claim 1, characterized in that, The signal acquisition device includes a multi-channel signal analyzer, a voltmeter, and wires; the wires are respectively connected to the two ends of the small-sized metal sample along its length and the voltmeter; the multi-channel signal analyzer is used to synchronously record voltage signals, load displacement signals, and environmental parameters.

3. The method for monitoring the integrity of small-sized metal samples under high pressure according to claim 1, characterized in that, The frequency at which the current switching device switches the current direction is 0.1~10Hz.

4. The method for monitoring the integrity of small-sized metal samples under high pressure according to claim 3, characterized in that, The loading system is also equipped with a clamping device, and the small-sized metal sample is electrically insulated from the clamping device by an insulating component.

5. The method for monitoring the integrity of small-sized metal samples under high pressure according to claim 2, characterized in that, The wire is welded to the small-sized metal sample.

6. The method for monitoring the integrity of small-sized metal samples under high pressure according to claim 1, characterized in that, The standard deviation threshold includes a first threshold and a second threshold: when the real-time voltage value deviates from the initial average value by more than the first threshold but not more than the second threshold, the small-sized metal sample undergoes partial fracture; when the real-time voltage value deviates from the initial average value by more than the second threshold, the small-sized metal sample undergoes complete fracture.

7. The method for monitoring the integrity of small-sized metal samples under high pressure according to claim 6, characterized in that, The first threshold is 3 to 5 times the standard deviation of the initial voltage value, and the second threshold is 10 to 100 times the standard deviation of the initial voltage value.

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