System and method for testing fracture toughness of hydrogen-doped pipeline material

Abstract

The invention discloses a hydrogen-doped pipeline material fracture toughness testing system and a testing method thereof. The hydrogen-doped pipeline material fracture toughness testing system comprises an environment box, a gas supply assembly, a loading and fixing device, an acoustic emission monitoring system and a signal processing and control system. A test cavity is defined in the environment box, the environment box comprises a box body and a cover plate, the cover plate covers the top of the box body, and a first air inlet, a second air inlet and an exhaust port are formed in the cover plate. The gas supply assembly comprises a hydrogen tank, a hydrogen pipeline, an inert gas tank and an inert gas pipeline, the loading and fixing device is used for clamping a CT sample and loading a tensile load on the CT sample, and the DIC strain measurement device is used for performing continuous imaging on the surface of the CT sample; the acoustic emission monitoring system is used for collecting acoustic signals generated in the tensile process of the CT sample in real time. According to the system for testing the fracture toughness of the hydrogen-doped pipeline material, the accuracy and the reliability of a test result are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of mechanical property testing of hydrogen-doped pipeline materials, and in particular to a fracture toughness testing system and method for hydrogen-doped pipeline materials. Background Technology

[0002] With the widespread application of hydrogen energy in storage, transportation, refueling, and industrial fields, hydrogen transportation and hydrogen-blended pipelines face significant risks of hydrogen embrittlement during service. Hydrogen atoms entering metals reduce the material's plasticity and fracture toughness, making cracks more prone to initiation and propagation, thus threatening the structural integrity of the pipeline. Therefore, accurately obtaining the fracture toughness parameters of pipeline materials under similar hydrogen environments is of significant engineering importance for ensuring the safety of hydrogen transportation systems.

[0003] Current fracture toughness studies primarily employ compact tensile (CT) specimens, pre-filling the material with hydrogen before mechanical testing in ambient air. However, electrochemical hydrogen filling introduces excessively high hydrogen concentrations, corrosion products, and uneven hydrogen distribution, significantly differing from actual gaseous hydrogen conditions. Furthermore, high-pressure pre-filling is prone to hydrogen escape after removal, making it difficult to maintain a stable hydrogen-containing state during testing and affecting the reliability of fracture toughness evaluation. In addition, traditional testing relies mainly on load-displacement curves to infer crack propagation, failing to directly capture local strain at the crack tip and hindering the observation of the sudden characteristics of hydrogen embrittlement crack initiation and propagation. While acoustic emission technology can reflect transient acoustic information of crack formation and propagation, it cannot provide the strain field at the crack tip. Non-contact full-field strain measurement systems (Digital Image Correlation, DIC) can achieve full-field strain measurement, but are limited by the optical arrangement in a closed hydrogen environment, making stable operation of existing systems difficult under hydrogen-filled conditions. Therefore, the two technologies have not yet been applied simultaneously in a gaseous hydrogen environment, nor can they be time-aligned with the loading process, which limits the multi-physics understanding of the evolution of hydrogen embrittlement cracks in hydrogen-doped pipeline materials. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, one objective of this invention is to propose a fracture toughness testing system for hydrogen-doped pipeline materials. This system enables simultaneous multi-physics monitoring of the entire fracture toughness testing process of CT samples of hydrogen-doped pipeline materials under a gaseous hydrogen-filled environment. The system can stably maintain the test atmosphere, ensuring the hydrogen-containing state of the material during loading. Simultaneously, it collects acoustic emission signals of crack initiation and propagation, as well as full-field strain information in real time, achieving time alignment and fusion analysis of mechanical load, acoustic response, and strain field. Through comprehensive processing of multi-source data, it can accurately obtain the strain distribution at the crack tip, crack propagation rate, and fracture toughness parameters, significantly improving the accuracy and reliability of the test results.

[0005] The present invention also proposes a method for testing the fracture toughness of hydrogen-doped pipeline materials under gaseous hydrogen-filled conditions using the above-mentioned hydrogen-doped pipeline material fracture toughness testing system.

[0006] A fracture toughness testing system for hydrogen-doped pipe materials according to a first aspect of the present invention includes: an environmental chamber defining a test chamber within the environmental chamber, the environmental chamber including a chamber body and a cover plate, the cover plate covering the top of the chamber body, the cover plate having a first air inlet, a second air inlet, and an exhaust port; a gas supply assembly including a hydrogen tank, a hydrogen pipeline, an inert gas tank, and an inert gas pipeline, one end of the hydrogen pipeline being connected to the hydrogen tank, the other end of the hydrogen pipeline being connected to the first air inlet, one end of the inert gas pipeline being connected to the inert gas tank, the other end of the inert gas pipeline being connected to the second air inlet, the hydrogen pipeline having a first control valve, and the inert gas pipeline having a second control valve; and a loading and fixing device including a loading device and a clamping assembly, the clamping assembly... A holding assembly is located inside the test chamber and is used to clamp the CT sample. The loading device is located outside the environmental chamber and connected to the holding assembly to apply a tensile load to the CT sample. A DIC strain measurement device includes a DIC camera, which is located inside the environmental chamber and is used to continuously image the surface of the CT sample. An acoustic emission monitoring system includes an acoustic emission sensor, which is fixed to the CT sample through a coupling agent to collect acoustic signals generated by the CT sample during tensile testing in real time. A signal processing and control system is connected to both the DIC strain measurement device and the acoustic emission monitoring system. The signal processing and control system is used to synchronously acquire, process, and fuse the acoustic signals and the images collected by the DIC strain measurement device.

[0007] The fracture toughness testing system for hydrogen-doped pipeline materials according to embodiments of the present invention can realize multi-physics field synchronous monitoring of the entire process of fracture toughness testing of CT specimens of hydrogen-doped pipeline materials in a gaseous hydrogen-filled environment. The system can stably maintain the test atmosphere, ensure the hydrogen-containing state of the material during loading, and simultaneously acquire acoustic emission signals of crack initiation and propagation and full-field strain information in real time. It can realize time alignment and fusion analysis of mechanical load, acoustic response and strain field. Through comprehensive processing of multi-source data, the strain distribution at the crack tip, crack propagation rate and fracture toughness parameters can be accurately obtained, significantly improving the accuracy and reliability of the test results.

[0008] According to some embodiments of the present invention, an exhaust system is also included, the exhaust system comprising an exhaust pipe and an exhaust gas recovery tank, one end of the exhaust pipe being connected to the exhaust port, the other end of the exhaust pipe being connected to the exhaust gas recovery tank, and a third control valve being provided on the exhaust pipe.

[0009] According to some embodiments of the present invention, the environmental chamber is provided with a first through hole and a second through hole on both sides along the vertical direction, and the loading and fixing device includes a first clamp and a second clamp arranged along the vertical direction. The first clamp and the second clamp are both located in the test chamber. The first clamp is connected to the loading device by a first connecting rod, which extends along the vertical direction and passes through the first through hole. The second clamp is connected to the loading device by a second connecting rod, which extends along the vertical direction and passes through the second through hole.

[0010] According to some embodiments of the present invention, the first clamp has a first clamping port for clamping the CT sample, the second clamp has a second clamping port for clamping the CT sample, the CT sample has a transversely extending pre-crack in the middle, the first clamp and the second clamp are respectively used to clamp the upper and lower parts of the CT sample located in the pre-crack, the first clamp is also provided with a first fixing hole, a first fixing member passes through the first fixing hole and the CT sample, the second clamp is also provided with a second fixing hole, a second fixing member passes through the second fixing hole and the CT sample.

[0011] According to some embodiments of the present invention, a first sealing element is provided between the outer peripheral wall of the first connecting rod and the inner peripheral wall of the first through hole, and a second sealing element is provided between the outer peripheral wall of the second connecting rod and the inner peripheral wall of the second through hole; According to some embodiments of the present invention, the clamping assembly is made of a hydrogen corrosion resistant material; and / or, the environmental chamber is made of a pressure-resistant and hydrogen corrosion resistant material.

[0012] According to some embodiments of the present invention, an observation chamber is further defined within the environmental chamber. The observation chamber is isolated from the test chamber by an observation window, which is transparent. The DIC camera is disposed in the observation chamber and is used to continuously image the surface of the CT sample through the observation window.

[0013] According to some embodiments of the present invention, the acoustic emission monitoring system further includes an acoustic emission preamplifier and an acoustic emission analyzer located outside the environmental chamber. The acoustic emission preamplifier is connected to the acoustic emission sensor and is used to amplify the acoustic signal received by the acoustic emission sensor. The acoustic emission analyzer is connected to the acoustic emission preamplifier and is used to perform feature extraction and signal localization analysis on the acoustic signal amplified by the acoustic emission preamplifier. The acoustic emission analyzer is connected to the signal processing and control system.

[0014] According to some embodiments of the present invention, the signal processing and control system includes a computer, which is wirelessly connected to the acoustic emission monitoring system and the DIC camera. The computer is used to perform time alignment, data integration, and visualization processing on the image data acquired by the DIC camera and the acoustic signals received by the acoustic emission monitoring system.

[0015] A method for testing the fracture toughness of hydrogen-doped pipeline materials according to a second aspect of the present invention, wherein the method uses the fracture toughness testing system for hydrogen-doped pipeline materials according to a first aspect of the present invention to test CT samples, the method comprising: S1. Prepare a CT sample, spray white primer on the surface of the CT sample, and after drying, spray black speckle to meet the imaging requirements of the DIC camera. S2. Fix the CT sample onto the clamping assembly, and seal the top of the box with the cover plate; S3. The gas supply assembly introduces hydrogen and inert gas into the test chamber; S4. Apply a tensile load to the CT specimen using the loading device; S5. Start the DIC strain measurement device and the acoustic emission monitoring system. The DIC camera continuously acquires images of the CT sample surface and transmits the image signals to the signal processing and control system. The acoustic emission monitoring system collects the acoustic signals and transmits them to the signal processing and control system. The signal processing and control system performs real-time processing, time alignment, and analysis on the image signals and acoustic signals acquired by the DIC camera, and calculates the strain distribution at the crack tip, crack propagation rate, and fracture toughness parameters.

[0016] The method for testing the fracture toughness of hydrogen-doped pipeline materials under gaseous hydrogen-filled conditions according to embodiments of the present invention, by using the fracture toughness testing system for hydrogen-doped pipeline materials according to the first aspect of the present invention, enables simultaneous multi-physics field monitoring of the entire process of fracture toughness testing of CT specimens of hydrogen-doped pipeline materials under gaseous hydrogen-filled conditions. The system can stably maintain the test atmosphere, ensure the hydrogen-containing state of the material during loading, and simultaneously acquire acoustic emission signals of crack initiation and propagation and full-field strain information in real time, realizing time alignment and fusion analysis of mechanical load, acoustic response and strain field. Through comprehensive processing of multi-source data, the strain distribution at the crack tip, crack propagation rate and fracture toughness parameters can be accurately obtained, significantly improving the accuracy and reliability of the test results.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a fracture toughness testing system for hydrogen-doped pipeline materials according to some embodiments of the present invention; Figure 2 yes Figure 1 A partial structural schematic diagram of the fracture toughness testing system for hydrogen-doped pipeline materials; Figure 3 yes Figure 2 A three-dimensional schematic diagram of the CT sample.

[0019] Figure label: 100. Fracture toughness testing system for hydrogen-doped pipeline materials; 1. Environmental chamber; 11. Test chamber; 12. Chamber body; 13. Cover plate; 14. First air inlet; 15. Second air inlet; 16. Exhaust port; 17. First through hole; 18. Second through hole; 2. Gas supply assembly; 21. Hydrogen tank; 22. Hydrogen pipeline; 23. Inert gas tank; 24. Inert gas pipeline; 25. First control valve; 26. Second control valve; 3. Exhaust system; 31. Exhaust pipe; 32. Waste gas recovery tank; 33. Third control valve; 4. Loading and fixing device; 41. Clamping assembly; 42. First clamp; 421. First clamping opening; 422. First fixing hole; 43. Second clamp; 431. Second clamping opening; 432. Second fixing hole; 44. First connecting rod; 45. Second connecting rod; 46. First fixing member; 47. Second fixing member; 5. DIC strain measurement device; 51. DIC camera; 6. Acoustic emission monitoring system; 61. Acoustic emission sensor; 62. Acoustic emission preamplifier; 63. Acoustic emission analyzer; 7. Signal processing and control systems; 71. Computer; 8. CT specimen. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following is for reference. Figures 1-2 A fracture toughness testing system 100 for hydrogen-doped pipe materials according to an embodiment of the present invention is described.

[0022] Reference Figure 1 and Figure 2 According to a first aspect of the present invention, a fracture toughness testing system 100 for hydrogen-doped pipeline materials includes: an environmental chamber 1, a gas supply assembly 2, a loading and fixing device 4, an acoustic emission monitoring system 6, and a signal processing and control system 7.

[0023] The environmental chamber 1 defines a test chamber 11. The environmental chamber 1 includes a chamber body 12 and a cover plate 13. The cover plate 13 is placed on the top of the chamber body 12. The cover plate 13 has a first air inlet 14, a second air inlet 15 and an exhaust port 16.

[0024] The gas supply assembly 2 includes a hydrogen tank 21, a hydrogen pipeline 22, an inert gas tank 23, and an inert gas pipeline 24. One end of the hydrogen pipeline 22 is connected to the hydrogen tank 21, and the other end of the hydrogen pipeline 22 is connected to the first gas inlet 14. One end of the inert gas pipeline 24 is connected to the inert gas tank 23, and the other end of the inert gas pipeline 24 is connected to the second gas inlet 15. A first control valve 25 is provided on the hydrogen pipeline 22, and a second control valve 26 is provided on the inert gas pipeline 24.

[0025] The loading and fixing device 4 includes a loading device and a clamping assembly 41. The clamping assembly 41 is located inside the test chamber 11 and is used to clamp the CT specimen 8. The loading device is located outside the environmental chamber 1 and is connected to the clamping assembly 41 to apply a tensile load to the CT specimen 8.

[0026] The DIC strain measurement device 5 includes a DIC camera 51, which is located inside the environmental chamber 1 and is used to continuously image the surface of the CT specimen 8. The acoustic emission monitoring system 6 includes an acoustic emission sensor 61, which is fixed in contact with the CT sample 8 through a coupling agent to collect the acoustic signals generated by the CT sample 8 during the tensile process in real time.

[0027] The signal processing and control system 7 is connected to both the DIC strain measurement device 5 and the acoustic emission monitoring system 6. The signal processing and control system 7 is used to synchronously acquire, process, and fuse the acoustic signals and the images collected by the DIC strain measurement device 5.

[0028] The test chamber 1, consisting of a body and a cover plate 13, is used to maintain the stability of the experimental atmosphere and prevent hydrogen leakage. The environmental chamber 1 is made of pressure-resistant and hydrogen-corrosion-resistant materials and is equipped with a transparent observation window to allow for full-field strain measurement by a DIC industrial camera in a hydrogen-filled environment. This ensures the stability of the hydrogen-containing state of the sample during loading, thereby ensuring the accuracy and reliability of the experimental data.

[0029] Hydrogen gas in hydrogen tank 21 is introduced into environmental chamber 1 through hydrogen tank 21, and the flow rate of hydrogen gas is regulated by first control valve 25; inert gas in inert gas tank 23 is introduced into environmental chamber 1 through inert gas pipeline 24, and the flow rate of inert gas gas is regulated by second control valve 26.

[0030] The loading and testing fixation system securely mounts the CT specimen 8 using the clamping assembly 41 and applies a controllable tensile load to ensure the stability and uniformity of the specimen during the loading process.

[0031] The acoustic emission monitoring system 6 can acquire acoustic signals generated by crack initiation and propagation in the sample in real time and transmit them to the computer 71 for processing and analysis. The acoustic emission sensor 61 is fixed to the CT sample 8 through contact with a coupling agent, which improves the accuracy of the acoustic signal received by the sensor 61 and allows for real-time acquisition of acoustic signals generated by crack initiation and propagation in the CT sample 8 during loading. The DIC strain measurement device 5 uses a DIC camera to continuously acquire images of the sample surface, which can capture images of the crack initiation and propagation process, realizing non-contact measurement of the strain at the crack tip and throughout the entire field.

[0032] The signal processing and control system 7 synchronously acquires and fuses data from the loading and test fixing system, acoustic emission monitoring system 6, and DIC strain measurement device 5, enabling real-time monitoring of multi-physics information and providing accurate and reliable data support for fracture toughness testing of hydrogen-doped pipeline materials.

[0033] Through the above technical solution, this invention enables simultaneous multi-physics monitoring of the entire fracture toughness test process of CT specimen 8, a hydrogen-doped pipeline material, under a gaseous hydrogen-filled environment. The system can stably maintain the test atmosphere, ensuring the hydrogen-containing state of the material during loading, while simultaneously acquiring acoustic emission signals of crack initiation and propagation, as well as full-field strain information in real time, achieving time alignment and fusion analysis of mechanical load, acoustic response, and strain field. Through comprehensive processing of multi-source data, the strain distribution at the crack tip, crack propagation rate, and fracture toughness parameters can be accurately obtained, significantly improving the accuracy and reliability of the test results.

[0034] The fracture toughness testing system 100 for hydrogen-doped pipeline materials according to an embodiment of the present invention can realize multi-physics field synchronous monitoring of the entire fracture toughness testing process of CT specimens 8 of hydrogen-doped pipeline materials in a gaseous hydrogen-filled environment. The system can stably maintain the test atmosphere, ensure the hydrogen-containing state of the material during loading, and simultaneously acquire acoustic emission signals of crack initiation and propagation and full-field strain information in real time. It can realize time alignment and fusion analysis of mechanical load, acoustic response and strain field. Through comprehensive processing of multi-source data, the strain distribution at the crack tip, crack propagation rate and fracture toughness parameters can be accurately obtained, significantly improving the accuracy and reliability of the test results.

[0035] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, an exhaust system 3 is also included. The exhaust system 3 includes an exhaust pipe 31 and a waste gas recovery tank 32. One end of the exhaust pipe 31 is connected to an exhaust port 16, and the other end of the exhaust pipe 31 is connected to the waste gas recovery tank 32. A third control valve 33 is provided on the exhaust pipe 31. By including the waste gas recovery tank 32 in the exhaust system 3, the gas enters the exhaust pipe 31 from the exhaust port 16 and then enters the waste gas recovery tank 32 for safe collection, recycling, or treatment, thereby preventing hydrogen from being directly discharged into the laboratory environment.

[0036] This system can maintain the hydrogen concentration and total pressure in the environmental chamber 1 in real time by precisely controlling the flow and pressure of hydrogen and inert gas, ensuring that the hydrogen content in the space where the CT sample 8 is located remains constant during the test. At the same time, hydrogen is recovered through the exhaust gas recovery tank 32 of the exhaust system 3, effectively preventing hydrogen leakage and ensuring the safety and repeatability of the experiment.

[0037] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, the environmental chamber 1 is provided with a first through hole 17 and a second through hole 18 on both sides along the vertical direction. The loading and fixing device 4 includes a first clamp 42 and a second clamp 43 arranged along the vertical direction. The first clamp 42 and the second clamp 43 are both located in the test chamber 11. The first clamp 42 is connected to the loading device through a first connecting rod 44. The first connecting rod 44 extends along the vertical direction and passes through the first through hole 17. The second clamp 43 is connected to the loading device through a second connecting rod 45. The second connecting rod 45 extends along the vertical direction and passes through the second through hole 18.

[0038] By extending the first connecting rod 44 vertically and passing through the first through hole 17, and extending the second connecting rod 45 vertically and passing through the second through hole 18, the first connecting rod 44 and the second connecting rod 45 can move relative to the environmental chamber 1. When the loading device applies force to the first connecting rod 44 and the second connecting rod 45, the first connecting rod 44 and the second connecting rod 45 can move away from each other, causing the first clamp 42 and the second clamp 43 to move away from each other, thereby achieving a tensile effect on the CT sample 8.

[0039] For example, the loading device can precisely control the tensile speed and loading force, enabling controllable loading throughout the entire crack propagation process of the specimen.

[0040] Reference Figure 1 and Figure 2According to some embodiments of the present invention, the first clamp 42 has a first clamping port 421 for clamping the CT sample 8, and the second clamp 43 has a second clamping port 431 for clamping the CT sample 8. The CT sample 8 has a transversely extending pre-crack in the middle. The first clamp 42 and the second clamp 43 are respectively used to clamp the upper and lower parts of the CT sample 8 located on the pre-crack. The first clamp 42 is also provided with a first fixing hole 422, and a first fixing member 46 passes through the first fixing hole 422 and the CT sample 8. The second clamp 43 is also provided with a second fixing hole 432, and a second fixing member 47 passes through the second fixing hole 432 and the CT sample 8.

[0041] By using the first clamp 42 and the second clamp 43 to clamp the upper and lower parts of the CT sample 8 respectively, the CT sample 8 can be fully clamped by the first clamp 42 and the second clamp 43, and the crack will initiate in the middle part of the CT sample 8, so as to facilitate the imaging by the DIC camera 51. By providing a first fixing hole 422 on the first clamp 42, and the first fixing member 46 passing through the first fixing hole 422 and the CT sample 8, the connection between the first clamp 42 and the CT sample 8 can be made more stable, preventing the sample from shifting or rotating during the test, ensuring that the mechanical boundary conditions of the crack initiation and propagation process are stable and reliable, and preventing the CT sample 8 from falling off the first clamp 42; by providing a second fixing hole 432 on the second clamp 43, and the second fixing member 47 passing through the second fixing hole 432 and the CT sample 8, the connection between the second clamp 43 and the CT sample 8 can be made more stable, and preventing the CT sample 8 from falling off the second clamp 43.

[0042] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, a first sealing element is provided between the outer peripheral wall of the first connecting rod 44 and the inner peripheral wall of the first through hole 17, and a second sealing element is provided between the outer peripheral wall of the second connecting rod 45 and the inner peripheral wall of the second through hole 18.

[0043] By providing a first sealing element between the outer peripheral wall of the first connecting rod 44 and the inner peripheral wall of the first through hole 17, the sealing performance between the first connecting rod 44 and the first through hole 17 can be improved, preventing hydrogen from escaping and leaking between the outer peripheral wall of the first connecting rod 44 and the inner peripheral wall of the first through hole 17 and causing danger. It can also ensure that there is a sufficient hydrogen concentration in the environmental chamber 1.

[0044] By providing a second sealing element between the outer peripheral wall of the second connecting rod 45 and the inner peripheral wall of the second through hole 18, the sealing performance between the second connecting rod 45 and the second through hole 18 can be improved, preventing hydrogen from escaping and leaking between the outer peripheral wall of the second connecting rod 45 and the inner peripheral wall of the second through hole 18 and causing danger. It can also ensure that there is a sufficient hydrogen concentration in the environmental chamber 1.

[0045] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, the clamping assembly 41 is made of a hydrogen corrosion resistant material. By making the clamping assembly 41 a hydrogen corrosion resistant material, corrosion and cracking of the clamping assembly 41 are avoided, which would lead to inaccurate testing.

[0046] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, the environmental chamber 1 is made of pressure-resistant and hydrogen corrosion-resistant materials. By making the environmental chamber 1 of pressure-resistant and hydrogen corrosion-resistant materials, hydrogen leakage caused by cracking or damage to the environmental chamber 1 can be avoided.

[0047] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, an observation chamber is further defined within the environmental chamber 1. The observation chamber is isolated from the test chamber 11 by an observation window, which is transparent. A DIC camera 51 is located in the observation chamber and is used to continuously image the surface of the CT sample 8 through the observation window.

[0048] By defining an observation chamber isolated from the test chamber 11 within the environmental chamber 1, and placing the DIC camera 51 within the observation chamber (which is free of hydrogen gas), damage to the DIC camera 51 from hydrogen corrosion can be avoided. By setting an observation window to isolate the observation chamber from the test chamber 11, the DIC camera 51 can continuously image the surface of the CT sample 8 through the observation window, collecting imaging data which is then transmitted to the signal processing and control system 7 for synchronization, forming multi-physics fusion information. This provides a direct view of the strain evolution of the material during crack initiation, propagation, and fracture, offering accurate and quantifiable experimental data for assessing the fracture toughness of hydrogen-doped pipe materials and studying hydrogen embrittlement mechanisms.

[0049] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, the acoustic emission monitoring system 6 further includes an acoustic emission preamplifier 62 and an acoustic emission analyzer 63 located outside the environmental chamber 1. The acoustic emission preamplifier 62 is connected to the acoustic emission sensor 61 and is used to amplify the acoustic signal received by the acoustic emission sensor 61. The acoustic emission analyzer 63 is connected to the acoustic emission preamplifier 62 and is used to perform feature extraction and signal localization analysis on the amplified acoustic signal. The acoustic emission analyzer 63 is connected to the signal processing and control system 7. The weak acoustic signal is amplified by the acoustic emission preamplifier 62 and then transmitted to the acoustic emission analyzer 63 for feature extraction and signal localization analysis. The acoustic emission monitoring system 6 can capture key acoustic information on crack initiation, propagation rate, and fracture instant, and provide accurate and reliable experimental data support for the hydrogen embrittlement behavior and fracture toughness of hydrogen-doped pipeline materials.

[0050] Reference Figure 1 and Figure 2 According to some embodiments of the present invention, the signal processing and control system 7 includes a computer 71, which is wirelessly connected to the acoustic emission monitoring system 6 and the DIC camera 51. The computer 71 is used to perform time alignment, data integration, and visualization processing on the image data acquired by the DIC camera 51 and the acoustic signals received by the acoustic emission monitoring system 6. The system achieves real-time multi-physics monitoring of the entire process of crack initiation and propagation in the CT specimen 8 by performing time alignment, data integration, and visualization processing on three types of data: the acoustic signals from the acoustic emission monitoring system 6, the image signals from the DIC camera 51, and the tensile data. Through this system, local strain concentration, crack propagation rate, and fracture toughness parameters can be displayed intuitively. Simultaneously, feature extraction and crack location analysis of the acoustic signals are performed, providing accurate and reliable data support for fracture toughness testing of hydrogen-doped pipe materials in a gaseous hydrogen-filled environment. Furthermore, the control software can also realize the linkage control of the gas supply and emission system, the loading device, and the measurement system, improving the level of experimental automation and the repeatability of the experimental process.

[0051] By wirelessly connecting the computer 71 to the acoustic emission monitoring system 6 and the DIC camera 51, there is no need to set up a connection harness, avoiding the need to open additional openings for wiring on the environmental enclosure 1, thus improving the sealing performance of the environmental enclosure 1.

[0052] According to a second aspect embodiment of the present invention, a method for testing the fracture toughness of hydrogen-doped pipeline materials is provided. The method employs the hydrogen-doped pipeline material fracture toughness testing system 100 of the first aspect embodiment of the present invention to test the CT sample 8. The method includes: S1. Prepare CT sample 8. Spray white primer on the surface of CT sample 8, and after drying, spray black speckle to meet the imaging requirements of DIC camera 51. S2. Fix the CT sample 8 onto the clamping assembly 41 and seal the top of the box 12 with the cover plate 13; S3. The gas supply component 2 introduces hydrogen and inert gas into the test chamber 11; S4. Apply a tensile load to the CT specimen 8 using the loading device; S5. Start the DIC strain measurement device 5 and acoustic emission monitoring system 6. The DIC camera 51 continuously acquires images of the surface of the CT sample 8 and transmits the image signals to the signal processing and control system 7. The acoustic emission monitoring system 6 collects acoustic signals and transmits them to the signal processing and control system 7. The signal processing and control system 7 performs real-time processing, time alignment and analysis on the image signals and acoustic signals acquired by the DIC camera 51, and calculates the strain distribution at the crack tip, crack propagation rate and fracture toughness parameters.

[0053] Among them, black speckle consists of multiple black spots arranged randomly or in an array.

[0054] According to the embodiment of the present invention, the method for testing the fracture toughness of hydrogen-doped pipeline materials under gaseous hydrogen-filled conditions, by using the hydrogen-doped pipeline material fracture toughness testing system 100 according to the first aspect of the present invention, can realize multi-physics field synchronous monitoring of the entire process of fracture toughness testing of CT specimen 8 of hydrogen-doped pipeline materials under gaseous hydrogen-filled environment. The system can stably maintain the test atmosphere, ensure the hydrogen-containing state of the material during loading, and simultaneously acquire acoustic emission signals of crack initiation and propagation and full-field strain information in real time, realizing time alignment and fusion analysis of mechanical load, acoustic response and strain field. Through comprehensive processing of multi-source data, the strain distribution at the crack tip, crack propagation rate and fracture toughness parameters can be accurately obtained, significantly improving the accuracy and reliability of the test results.

[0055] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0056] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0057] In the description of this invention, "a plurality of" means two or more.

[0058] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0059] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A fracture toughness testing system for hydrogen-doped pipeline materials, characterized in that, include: An environmental chamber, which defines a test chamber, includes a chamber body and a cover plate, the cover plate being placed on the top of the chamber body, and the cover plate having a first air inlet, a second air inlet and an exhaust port; A gas supply assembly includes a hydrogen tank, a hydrogen pipeline, an inert gas tank, and an inert gas pipeline. One end of the hydrogen pipeline is connected to the hydrogen tank, and the other end of the hydrogen pipeline is connected to the first gas inlet. One end of the inert gas pipeline is connected to the inert gas tank, and the other end of the inert gas pipeline is connected to the second gas inlet. A first control valve is provided on the hydrogen pipeline, and a second control valve is provided on the inert gas pipeline. A loading and fixing device includes a loading device and a clamping assembly, wherein the clamping assembly is located inside the test chamber and is used to clamp the CT specimen, and the loading device is located outside the environmental chamber and connected to the clamping assembly for applying a tensile load to the CT specimen. The DIC strain measurement device includes a DIC camera, which is located inside the environmental chamber and is used to continuously image the surface of the CT specimen. An acoustic emission monitoring system includes an acoustic emission sensor, which is fixed in contact with a CT sample via a coupling agent to collect acoustic signals generated by the CT sample during tensile testing in real time. The signal processing and control system is connected to both the DIC strain measurement device and the acoustic emission monitoring system. The signal processing and control system is used to synchronously acquire, process, and fuse the acoustic signals and the images collected by the DIC strain measurement device.

2. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 1, characterized in that, It also includes an exhaust system, which includes an exhaust pipe and an exhaust gas recovery tank. One end of the exhaust pipe is connected to the exhaust port, and the other end of the exhaust pipe is connected to the exhaust gas recovery tank. A third control valve is provided on the exhaust pipe.

3. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 1, characterized in that, The environmental chamber has a first through hole and a second through hole on both sides along the vertical direction. The loading and fixing device includes a first clamp and a second clamp arranged along the vertical direction. Both the first clamp and the second clamp are located inside the test chamber. The first clamp is connected to the loading device through a first connecting rod, which extends along the vertical direction and passes through the first through hole. The second clamp is connected to the loading device through a second connecting rod, which extends along the vertical direction and passes through the second through hole.

4. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 3, characterized in that, The first clamp has a first clamping port for clamping the CT sample, and the second clamp has a second clamping port for clamping the CT sample. The CT sample has a transversely extending pre-crack in the middle. The first clamp and the second clamp are respectively used to clamp the upper and lower parts of the CT sample located on the pre-crack. The first clamp is also provided with a first fixing hole, and a first fixing member passes through the first fixing hole and the CT sample. The second clamp is also provided with a second fixing hole, and a second fixing member passes through the second fixing hole and the CT sample.

5. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 3, characterized in that, A first sealing element is provided between the outer peripheral wall of the first connecting rod and the inner peripheral wall of the first through hole, and a second sealing element is provided between the outer peripheral wall of the second connecting rod and the inner peripheral wall of the second through hole.

6. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 1, characterized in that, The clamping assembly is made of a hydrogen corrosion resistant material; and / or the environmental chamber is made of a pressure resistant and hydrogen corrosion resistant material.

7. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 1, characterized in that, The environmental chamber also defines an observation cavity, which is isolated from the test cavity by an observation window. The observation window is transparent, and the DIC camera is located in the observation cavity and is used to continuously image the surface of the CT sample through the observation window.

8. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 1, characterized in that, The acoustic emission monitoring system also includes an acoustic emission preamplifier and an acoustic emission analyzer located outside the environmental chamber. The acoustic emission preamplifier is connected to the acoustic emission sensor and is used to amplify the acoustic signal received by the acoustic emission sensor. The acoustic emission analyzer is connected to the acoustic emission preamplifier and is used to perform feature extraction and signal localization analysis on the acoustic signal amplified by the acoustic emission preamplifier. The acoustic emission analyzer is connected to the signal processing and control system.

9. The fracture toughness testing system for hydrogen-doped pipeline materials according to claim 1, characterized in that, The signal processing and control system includes a computer, which is wirelessly connected to the acoustic emission monitoring system and the DIC camera. The computer is used to perform time alignment, data integration, and visualization processing on the image data acquired by the DIC camera and the acoustic signals received by the acoustic emission monitoring system.

10. A method for testing the fracture toughness of hydrogen-doped pipe materials, characterized in that, The test method uses the fracture toughness testing system for hydrogen-doped pipeline materials according to any one of claims 1-9 to test the CT sample, and the test method includes: S1. Prepare a CT sample, spray white primer on the surface of the CT sample, and after drying, spray black speckle to meet the imaging requirements of the DIC camera. S2. Fix the CT sample onto the clamping assembly, and seal the top of the box with the cover plate; S3. The gas supply assembly introduces hydrogen and inert gas into the test chamber; S4. Apply a tensile load to the CT specimen using the loading device; S5. Start the DIC strain measurement device and the acoustic emission monitoring system. The DIC camera continuously acquires images of the CT sample surface and transmits the image signals to the signal processing and control system. The acoustic emission monitoring system collects the acoustic signals and transmits them to the signal processing and control system. The signal processing and control system performs real-time processing, time alignment, and analysis on the image signals and acoustic signals acquired by the DIC camera, and calculates the strain distribution at the crack tip, crack propagation rate, and fracture toughness parameters.

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