Method and system for identifying damage characteristics of hydrogen storage cylinder

Abstract

The invention relates to the technical field of hydrogen storage cylinder state detection, in particular to a hydrogen storage cylinder damage characteristic identification method and system, and the method comprises the steps: S1, collecting and storing a damage data threshold value of a hydrogen storage cylinder sample, and a low-cycle fatigue data threshold value of each different region on the hydrogen storage cylinder; s2, arranging a sensor network for detection in each area of the target hydrogen storage cylinder, and collecting structural response data of the target hydrogen storage cylinder in real time; s3, if the structural response data is not lower than a damage data threshold value, judging that the target hydrogen storage cylinder is subjected to structural damage; s4, if the structural damage is not detected, acquiring a target position where the fatigue structural crack occurs in the area; and S5, predicting the fatigue life of the target hydrogen storage cylinder according to the fatigue structure crack degree of the target position. According to the invention, whether the hydrogen storage cylinder is damaged or not can be accurately and rapidly identified.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage cylinder condition detection technology, specifically to a method and system for identifying damage characteristics of hydrogen storage cylinders. Background Technology

[0002] In the energy sector, hydrogen energy, as a clean and efficient energy source, has attracted much attention. Hydrogen storage cylinders, as key equipment for storing hydrogen, are of paramount importance in terms of safety and reliability. During use, hydrogen storage cylinders are affected by various factors, such as repeated filling and discharging, changes in internal hydrogen pressure, and external environmental temperature and humidity. These factors can lead to damage to the cylinders, such as deformation and thinning of the walls. With the development of industries such as hydrogen fuel cell vehicles, the use of hydrogen storage cylinders is becoming increasingly widespread, making damage detection a crucial aspect of ensuring safety. Existing methods for inspecting hydrogen storage cylinders have certain limitations. For example, while hydrostatic testing can detect the strength and sealing of the cylinder, it cannot monitor internal damage in real time; ultrasonic testing can detect internal defects, but it is complex to operate and requires highly skilled personnel.

[0003] In existing technologies, such as the high-pressure hydrogen storage container damage status monitoring method, device, and system described in patent application number 202410789640.9, damage status monitoring involves steps including database establishment, information acquisition, wall thickness calculation, wall thickness comparison, ultrasonic detection, defect determination, defect pressure calculation, pressure judgment, health status judgment, maintenance, and repair. The device includes a memory and a processor; the system includes a database, an information acquisition module, a wall thickness calculation module, a wall thickness comparison module, an ultrasonic detection module, a defect determination module, a defect pressure calculation module, a pressure judgment module, a health status judgment module, a maintenance module, and a repair module to improve damage identification of hydrogen storage cylinders. However, this method can only identify damage when it occurs in the cylinder, which has significant limitations. Summary of the Invention

[0004] The present invention aims to provide a method and system for identifying the damage characteristics of hydrogen storage cylinders. Even when no structural damage has occurred, the system can accurately predict the future service life of hydrogen storage cylinders based on fatigue structural cracks. This allows for a single inspection of the hydrogen storage cylinder to determine whether it has been damaged or to predict how long it will take to become damaged, thus saving on the number of inspections and inspection costs.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first scheme provides a method for identifying damage characteristics of hydrogen storage cylinders, comprising: S1: collecting and storing damage data thresholds for hydrogen storage cylinder samples, and low-cycle fatigue data thresholds for different regions on the hydrogen storage cylinder; S2: deploying a sensor network for detection in various regions of the target hydrogen storage cylinder, and collecting structural response data of the target hydrogen storage cylinder in real time; S3: if the structural response data is not lower than the damage data threshold, then determining that the target hydrogen storage cylinder has suffered structural damage; S4: if no structural damage is detected, then partitioning the real-time structural response data according to the sensor distribution area, and comparing the data of each region with the fatigue data threshold of the corresponding region. If the structural response data of any region is not lower than the low-cycle fatigue data threshold of the corresponding region, then determining that the region has a fatigue structural crack, and further obtaining the target location of the fatigue structural crack in the region; S5: predicting the fatigue life of the target hydrogen storage cylinder based on the degree of fatigue structural crack occurrence at the target location.

[0006] Beneficial effects: Compared to existing technologies that can only detect damage to hydrogen storage cylinders through ultrasonic testing, but cannot determine the fatigue life of hydrogen storage cylinders using existing technologies such as ultrasonic testing, fatigue life detection is a problem that current technologies cannot solve. This is because it requires a comprehensive assessment of various areas of the hydrogen storage cylinder and the size of the selected testing area, and it cannot be evaluated using any data.

[0007] This solution divides the area into regions, each corresponding to a different fatigue data threshold. If the structural response data is not lower than the fatigue data threshold, the fatigue life of that region is considered to be short. This is beneficial for accurately assessing the next inspection time or service life of hydrogen storage cylinders in practical applications, reducing inspection costs, and enabling rapid and accurate assessment of the fatigue life of hydrogen storage cylinders through regional inspections.

[0008] Specifically, by collecting and storing damage data thresholds and low-cycle fatigue data thresholds, and utilizing a sensor network to monitor structural response data in real time, combined with zonal processing and comparative analysis, this method can accurately and rapidly identify whether hydrogen storage cylinders have structural damage or fatigue-induced structural cracks, and further predict their fatigue life. This method overcomes the limitations of existing detection methods, achieving comprehensive monitoring and assessment of the damage state of hydrogen storage cylinders, providing strong protection for the safe use of hydrogen storage cylinders, and has significant application value.

[0009] Preferably, before the hydrogen storage cylinder sample is put into production, a hydrostatic test is conducted to obtain the maximum strain force of the hydrogen storage cylinder sample, and the maximum strain force is used as the damage data threshold; before the hydrogen storage cylinder sample is put into production, a self-tightening test is conducted to obtain the self-tightening pressure of the hydrogen storage cylinder sample, and the self-tightening pressure is used as the low-cycle fatigue data threshold.

[0010] Beneficial effects: By using the maximum strain force obtained from the hydrostatic test as the damage data threshold for the hydrogen storage cylinder sample, and the self-tightening pressure obtained from the self-tightening test as the low-cycle fatigue data threshold, the scientific validity and rationality of the thresholds can be ensured. This method of determining thresholds based on actual process tests makes damage identification more accurate and reliable, avoiding misjudgments or omissions caused by unreasonable threshold settings, and further improving the accuracy of damage identification for hydrogen storage cylinders.

[0011] Preferably, according to thin film theory, the stress equation of the inner liner of the target hydrogen storage cylinder is:

[0012] Strain includes axial stress and circumferential stress, where, This represents axial stress, with units of MPa. The value represents the circumferential stress, in MPa; a and b represent the major and minor semi-axis of the target hydrogen storage cylinder, respectively, in mm; h represents the wall thickness of the target hydrogen storage cylinder, in mm; x represents the distance from any point on the target hydrogen storage cylinder to the central axis of the target hydrogen storage cylinder, in mm; and P represents the pressure exerted on the target hydrogen storage cylinder, in MPa.

[0013] Beneficial effects: The stress equation for the target hydrogen storage cylinder, based on thin-film theory, provides a theoretical basis for accurately calculating and analyzing the stress state of the cylinder. By clarifying the calculation method of strain and the relationship between various parameters, the stress distribution of the hydrogen storage cylinder under different operating conditions can be more accurately assessed, thereby more accurately determining its damage state. This provides more scientific support for subsequent damage identification and life prediction, enhancing the scientific rigor and accuracy of the method.

[0014] Preferably, the structural regions of the hydrogen storage cylinder include, in sequence, the equatorial plane of the end cap and the horizontal plane of the cylinder body; In S2, different numbers of sensors are arranged according to the stress of the inner liner. The number of sensors in each area from most to least is as follows: the equatorial surface of the end cap and the horizontal surface of the cylinder body. Among them, the sensors installed on the equatorial surface of the end cap are arranged in a ring, with the interval between two adjacent sensors not exceeding 200mm, and are used to accurately detect the structural response data of the equatorial surface of the end cap, which is subjected to the greatest shear force in the hydrogen storage cylinder. The sensors installed on the horizontal surface of the cylinder body are arranged in a dot matrix, with the interval between two adjacent sensors not less than 600mm.

[0015] Beneficial effects: The structural regions of the hydrogen storage cylinder were clearly defined, and different numbers of sensors were rationally arranged according to the stress levels within the liner, specifying the exact arrangement and spacing requirements of the sensors. This targeted sensor arrangement scheme enables more effective monitoring of the structural response data of critical components of the hydrogen storage cylinder, especially the vulnerable areas of the end cap equatorial plane and the cylinder body horizontal plane. Precise detection of the structural response data in these areas allows for more timely detection of potential damage, improving the sensitivity and accuracy of damage identification. It also helps to rationally utilize sensor resources and reduce costs.

[0016] Preferably, the ratio of the axial height of the end cap to the outer diameter of the inner liner is no more than [value missing]. .

[0017] Beneficial effects: Limiting the area ratio of the equatorial plane of the end cap to the horizontal plane of the cylinder helps to further optimize the sensor placement. A reasonable area ratio ensures that the sensors can more comprehensively and evenly cover the key areas of the hydrogen storage cylinder during monitoring, avoiding deviations or omissions in monitoring data due to excessive differences in area, thereby improving the performance and reliability of the entire damage identification system.

[0018] Preferably, in S5, the degree of fatigue structural crack is calculated based on the target location; if the target location is on the equatorial plane of the head, the fatigue damage in a first range around the target location is calculated based on the size and depth of the fatigue structural crack at the target location; if the target location is on the horizontal plane of the cylinder, the fatigue damage in a second range around the target location is calculated based on the size and depth of the fatigue structural crack at the target location; wherein, the first range is larger than the second range.

[0019] Beneficial effects: The degree of fatigue structural cracking is calculated separately based on the target location, and different damage ranges are set for the equatorial plane of the end cap and the horizontal plane of the cylinder body, with the first range being larger than the second. This differentiated approach fully considers the structural characteristics and stress conditions of different parts of the hydrogen storage cylinder, enabling a more accurate assessment of the impact of fatigue structural cracks on the overall performance of the hydrogen storage cylinder. This provides a more precise basis for subsequent fatigue life prediction, making the prediction results more targeted and accurate, and contributing to a more scientific assessment of the safety of the hydrogen storage cylinder.

[0020] Preferably, the fatigue life of the target hydrogen storage cylinder is predicted based on the degree of fatigue structural cracks occurring at the target location, y = -8126x + 15316, where y is the value of the number of fillings, which is used to characterize the fatigue life of the target hydrogen storage cylinder, and x is the depth of the fatigue structural crack.

[0021] Beneficial effects: The application of this formula makes fatigue life prediction more quantitative and intuitive, allowing for the direct calculation of the number of filling cycles—a numerical indicator of fatigue life—based on crack depth. This quantitative prediction method provides a clear reference for the maintenance and replacement of hydrogen storage cylinders, helping to develop reasonable maintenance plans in advance, avoiding safety accidents caused by fatigue failure, and further improving the safety of hydrogen storage cylinders during use.

[0022] The second approach includes a data analysis module, which includes an electronic device. The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it enables the electronic device to implement a hydrogen storage cylinder damage characteristic identification method as described in the first approach.

[0023] Beneficial Effects: By incorporating data analysis modules and electronic equipment, the aforementioned damage identification methods are combined with modern electronic technology, achieving automation and intelligence in the damage identification process. This system can efficiently process large amounts of monitoring data, quickly and accurately identify the damage state of hydrogen storage cylinders and predict their fatigue life, significantly improving detection efficiency and accuracy, reducing the complexity and error risk of manual operation, and demonstrating good practicality and operability. It provides a more advanced technical means for hydrogen storage cylinder damage monitoring. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a method for identifying damage characteristics of hydrogen storage cylinders according to Embodiment 1; Figure 2 This is a schematic diagram of the hydrogen storage cylinder in Example 1; Figure 3 This is a schematic diagram of the stress applied along the outer and inner paths of the equatorial surface of the head in Experiment Example 1. Figure 4 The figure shows the stress test results of various specifications of hydrogen storage cylinders along the axial length of the end cap under the outer path in Test Example 1. Figure 5 The figure shows the stress test results of various specifications of hydrogen storage cylinders along the axial length of the end cap under the inner path in Test Example 1. Figure 6 This is a schematic diagram of the axial stress distribution of the aluminum inner liner of the hydrogen storage cylinder under the hydrostatic test pressure (52.5 MPa) of Experiment Example 2. Figure 7 This is a schematic diagram of the axial stress distribution of the aluminum liner of the hydrogen storage cylinder under the allowable pressure (43.75 MPa) in Test Example 2. Figure 8 This is a schematic diagram of the axial stress distribution of the aluminum inner liner of the hydrogen storage cylinder under the self-tightening pressure (76 MPa) in Experiment Example 2. Figure 9 This is a schematic diagram of the Mises stress distribution of the aluminum inner liner under the self-tightening pressure (76 MPa) of Experiment Example 2. Figure 10 This is a schematic diagram of the Mises stress distribution of the aluminum inner liner under the water pressure test pressure (52.5 MPa) of Experiment Example 2. Figure 11 This is a schematic diagram of the Mises stress distribution of the aluminum inner liner under the allowable pressure (43.75 MPa) of Test Example 2. Figure 12 This is a schematic diagram of a hydrogen storage cylinder damage characteristic identification system according to Example 3; Figure 13 This is a schematic diagram of the electronic device structure in Example 3.

[0025] The reference numerals in the accompanying drawings include: 1. Equatorial plane of the end cap; 2. Horizontal plane of the cylinder body; 3. Sensor network; 4. A damage characteristic identification system for a hydrogen storage cylinder; 5. Processor; 6. Input device; 7. Output device; 8. Memory; 9. Bus; 100. Computer program; 104. Detailed Implementation

[0026] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.

[0027] Before describing the following embodiments and test examples, it should be noted that: Regarding the definition of strain in hydrogen storage cylinders: There is a significant difference in strength between the aluminum alloy liner and the carbon fiber composite material of hydrogen storage cylinders. After the self-tightening process, the liner undergoes plastic deformation, while the stress and strength of the carbon fiber composite material are relatively low. Therefore, the fatigue life of the carbon fiber composite material is considered to be much longer than that of the liner. Composite material cylinders are often scrapped during fatigue tests due to fatigue fracture of the liner. The fatigue determinant of composite high-pressure cylinders lies in the liner. Composite material cylinders rarely exceed 100,000 filling and discharging cycles during service, falling within the low-cycle fatigue range. The core of low-cycle fatigue is plastic strain-dominated failure.

[0028] In a specific implementation, the allowable pressure is also the upper limit pressure of low-cycle fatigue in fatigue testing.

[0029] Example 1 like Figure 1As shown, this embodiment provides a method for identifying the damage characteristics of hydrogen storage cylinders, including: S1, collect and store the damage data threshold of the hydrogen storage cylinder sample, as well as the low-cycle fatigue data threshold of different regions on the hydrogen storage cylinder.

[0030] Specifically, according to the technical terminology of this field, hydrogen storage cylinders before being put into production can be referred to as hydrogen storage cylinder samples. After being put into production and sold, users purchase hydrogen storage cylinders and then use them for a period of time for testing; that is, the hydrogen storage cylinders used for testing correspond to the target hydrogen storage cylinders. Before being put into production, the maximum strain force of the hydrogen storage cylinder sample is obtained through a hydrostatic test, and this maximum strain force is used as the damage data threshold. Furthermore, before being put into production, the self-tightening pressure of the hydrogen storage cylinder sample is measured through a self-tightening test, and this self-tightening pressure is used as the low-cycle fatigue data threshold.

[0031] According to thin film theory, the stress equation for the inner liner of the target hydrogen storage cylinder is:

[0032] Strain includes axial stress and circumferential stress, where, This represents axial stress, with units of MPa. The value represents the circumferential stress, in MPa; a and b represent the major and minor semi-axis of the target hydrogen storage cylinder, respectively, in mm; h represents the wall thickness of the target hydrogen storage cylinder, in mm; x represents the distance from any point on the target hydrogen storage cylinder to the central axis of the target hydrogen storage cylinder, in mm; and P represents the pressure exerted on the target hydrogen storage cylinder, in MPa.

[0033] S2: Arrange a sensor network for detection in each area of ​​the target hydrogen storage cylinder to collect the structural response data of the target hydrogen storage cylinder in real time.

[0034] Specifically, the sensor network used for detection includes FBG sensors, AE sensors, and strain gauge sensors. For example... Figure 2 As shown, different numbers of sensors are arranged according to the stress level of the inner liner. The number of sensors in each area, from most to least, is as follows: the equatorial surface of the end cap and the horizontal surface of the cylinder body. Among them, the sensors installed on the equatorial surface of the end cap are arranged in a ring, with the interval between two adjacent sensors not exceeding 200mm, and are used to accurately detect the structural response data of the equatorial surface of the end cap, which is subjected to the greatest shear force in the hydrogen storage cylinder.

[0035] In this embodiment, to accelerate and improve the accuracy of detection, after damage detection via S1, the fatigue structural crack region on the equatorial surface of the end cap is obtained. Sensors are then deployed within the target crack region, with a spacing of 100mm to 200mm between adjacent sensors. The main focus is on analyzing the propagation rate of the fatigue structural crack to determine the service life of the hydrogen storage cylinder.

[0036] The sensors installed on the horizontal plane of the cylinder are arranged in a dot matrix, with a spacing of no less than 600mm between adjacent sensors. The ratio of the axial height of the end cap (end cap height) to the axial height of the inner liner outside the cylinder is 1.25.

[0037] In existing technologies, hydrogen storage cylinders, compared to other types of gas cylinders (such as hydraulic cylinders), typically employ a composite structure of a "metal inner liner + carbon fiber / glass fiber composite winding layer" to meet the dual requirements of lightweight and high strength. In a high-pressure hydrogen environment, hydrogen molecules can dissociate into hydrogen atoms and penetrate into the surface of the metal inner liner, subsequently diffusing into the metal lattice, leading to lattice distortion, localized stress concentration, and ultimately inducing hydrogen embrittlement microcracks. Experimental examples show that hydrogen embrittlement microcracks often originate from metal surface defects, weld joints, or stress concentration areas, and exhibit a mixed propagation mode with fatigue cracks. Their interaction can trigger material failure, and the cracks are characterized by rapid propagation, sudden onset, and high concealment. Currently available ultrasonic damage detection technology can only identify whether cracks have appeared in the hydrogen storage cylinder, but it does not reveal the extent of crack propagation.

[0038] S3: If the structural response data is not lower than the damage data threshold, it is determined that the target hydrogen storage cylinder has suffered structural damage. S4: If no structural damage is detected, the real-time structural response data is partitioned according to the sensor distribution area, and the data of each region is compared with the fatigue data threshold of the corresponding region. If the structural response data of any region is not lower than the low-cycle fatigue data threshold of the corresponding region, it is determined that a fatigue structural crack has occurred in that region, and the target location of the fatigue structural crack in that region is further obtained. S5: The fatigue life of the target hydrogen storage cylinder is predicted based on the degree of fatigue structural crack occurrence at the target location.

[0039] Specifically, the degree of fatigue structural cracking is calculated based on the target location. If the target location is at the equatorial plane of the end cap, the fatigue damage within a first range around the target location is calculated based on the size and depth of the fatigue structural crack at the target location. If the target location is at the horizontal plane of the cylinder, the fatigue damage within a second range around the target location is calculated based on the size and depth of the fatigue structural crack at the target location; wherein, the first range is larger than the second range. In this embodiment, the first range is within 200mm of the target location, and the second range is within 600mm of the target location. In this embodiment, the equatorial plane of the end cap is located between the end cap and the cylinder, and the ratio of the axial height of the end cap to the outer diameter of the inner liner cylinder is 1.25.

[0040] The fatigue life of the target hydrogen storage cylinder is predicted based on the degree of fatigue structural cracking at the target location, using the formula: y = -8126x + 15316, where y represents the number of filling cycles, which characterizes the fatigue life of the target hydrogen storage cylinder, and x represents the depth of the fatigue structural crack. In this embodiment, both the damage data threshold and the low-cycle fatigue data threshold can be obtained from the hydrogen storage cylinder sample before it is put into production through hydrostatic testing and autotightening testing, respectively.

[0041] Beneficial effects of this embodiment First, comprehensive monitoring and precise identification are achieved. By collecting and storing damage data thresholds and low-cycle fatigue data thresholds for hydrogen storage cylinder samples, combined with real-time acquired structural response data, the damage status of hydrogen storage cylinders can be comprehensively monitored. This method can not only identify structural damage but also detect fatigue structural cracks, covering multiple damage types that may occur in hydrogen storage cylinders, avoiding the limitations of single detection methods. Simultaneously, by employing zonal processing and comparative analysis, the location of fatigue structural cracks can be precisely located, improving the accuracy of damage identification. This refined monitoring approach helps to promptly identify potential damage hazards and prevent further damage escalation.

[0042] Secondly, the threshold setting does not require multiple tests; only the test results of the original manufacturer's samples are needed. The damage data thresholds and low-cycle fatigue data thresholds obtained from hydrostatic and autotightening process tests ensure the scientific validity and rationality of the thresholds. These thresholds, determined based on actual process tests, can more accurately reflect the damage state of hydrogen storage cylinders in actual use, avoiding misjudgments or omissions caused by unreasonable threshold settings.

[0043] Furthermore, the sensor arrangement was optimized. Sensors were strategically placed according to the stress levels within the liner, employing a ring-shaped arrangement on the equatorial surface of the end cap and a dot-matrix arrangement on the horizontal surface of the cylinder body, with specified spacing requirements. This optimized sensor arrangement allows for more effective monitoring of structural response data in critical areas, particularly the vulnerable equatorial surface of the end cap, thus improving monitoring sensitivity and accuracy.

[0044] Finally, accurate lifespan prediction. Predicting the fatigue life of hydrogen storage cylinders by measuring the depth of fatigue-induced structural cracks provides a quantitative assessment method. This method can directly calculate the number of filling cycles based on crack depth, providing a clear reference for the maintenance and replacement of hydrogen storage cylinders. It helps in developing reasonable maintenance plans in advance and avoids safety accidents caused by fatigue failure.

[0045] Example 2 Unlike Embodiment 1, this embodiment provides a method for identifying the damage characteristics of hydrogen storage cylinders, focusing more on how to identify damage to hydrogen storage cylinders, specifically including: Calculate the standard structural characteristic data of the hydrogen storage cylinder sample. Calculate the complete deformation, residual deformation rate, and REE value of the hydrogen storage cylinder sample under hydrostatic testing as standard structural characteristic data; the REE value of the cylinder shall not exceed 1.1 times the average elastic expansion under hydrostatic testing pressure. The standard structural characteristic data of the hydrogen storage cylinder sample also includes the strain value of the inner liner under hydrostatic testing pressure, and the inner liner wall thickness information; wherein, the inner liner wall thickness information includes the outer diameter of the hydrogen storage cylinder, minimum design wall thickness, material, length, and theoretical minimum inner liner thickness. Based on finite element analysis, the minimum inner liner thickness must at least meet the requirement of a safe service life of the hydrogen storage cylinder reaching several thousand uses.

[0046] The sensor network used for damage detection acquires real-time data on whether the inner wall thickness of the target hydrogen storage cylinder is less than the minimum design wall thickness at the monitoring location. If so, the hydrogen storage cylinder is repaired using the first repair strategy; otherwise, the hydrogen storage cylinder is considered normal. In this embodiment, the first repair strategy can be based on existing technology.

[0047] The sensor network used for damage detection acquires real-time data on whether the strain inside the target hydrogen storage cylinder exceeds the strain value corresponding to the water pressure test pressure during cylinder manufacturing. If so, the first repair strategy is adopted to repair the target hydrogen storage cylinder; otherwise, the hydrogen storage cylinder is considered normal.

[0048] The sensor network used for damage detection acquires real-time data on whether the minimum wall thickness of the inner liner of the hydrogen storage cylinder is less than the minimum wall thickness under safe lifespan. If so, the first repair strategy is adopted to repair the hydrogen storage cylinder; otherwise, the hydrogen storage cylinder is considered normal.

[0049] The target hydrogen storage cylinder is subjected to strain testing to detect any abnormal deformation. The target hydrogen storage cylinder is also subjected to ultrasonic testing to detect any abnormal wall thickness. If the target hydrogen storage cylinder exhibits abnormal deformation or abnormal wall thickness, the first repair strategy is employed to repair the hydrogen storage cylinder.

[0050] Beneficial effects of this embodiment First, multi-dimensional damage identification. By calculating standard structural characteristic data of hydrogen storage cylinder samples, including the complete deformation, residual deformation rate, REE value, inner liner strain value, and wall thickness information under hydrostatic testing, the damage state of the hydrogen storage cylinder is assessed from multiple dimensions. This method can more comprehensively identify the damage characteristics of hydrogen storage cylinders and avoid misjudgments that may be caused by a single indicator.

[0051] Secondly, real-time monitoring and timely repair are crucial. Utilizing a sensor network to monitor key indicators such as the inner wall thickness and strain value of the hydrogen storage cylinder in real time allows for the timely detection of anomalies such as inner wall thickness less than the minimum design thickness or strain exceeding the hydrostatic test strain value, enabling the implementation of the primary repair strategy. This real-time monitoring and timely repair approach effectively prevents further damage and ensures the safe operation of the hydrogen storage cylinder.

[0052] Furthermore, safety assessments are enhanced. A combination of strain testing and ultrasonic testing is used to further confirm whether the hydrogen storage cylinders exhibit abnormal deformation or wall thickness. This multi-method testing approach can more accurately assess the safety of hydrogen storage cylinders, avoiding safety hazards caused by the limitations of a single testing method.

[0053] Finally, by combining real-time monitoring and multi-dimensional assessment, the damage status of hydrogen storage cylinders can be quickly and accurately identified, reducing the complexity and uncertainty of the detection process. This method not only improves detection efficiency but also reduces detection costs, demonstrating good practicality and economic efficiency.

[0054] Experimental Example 1 In this experimental example, a stress analysis was performed on the inner liner of a standard hydrogen storage cylinder, such as... Figure 3 As shown, stress output along the outer and inner paths reveals stress fluctuations on the inner surface of the liner, near the cylinder body, specifically at the equatorial plane of the end cap. Figure 4 As shown, the shear force generated will affect the fatigue life of the gas cylinder at this location. In fatigue tests of Type III gas cylinders, this location is also a common failure and leakage point.

[0055] On external paths, such as Figure 4As shown, the axial length of the end cap increases with increasing length, ranging from 100 to 450 mm, which corresponds to the axial length of the end cap's equatorial plane. While the stresses experienced by hydrogen storage cylinders vary across different proportions, in general, the stress at the end cap's equatorial plane increases with the axial length, resulting in stress concentration and peaks, indicated by two dashed boxes. This stress concentration generates shear forces that affect the fatigue life of the hydrogen storage cylinder at that location (the end cap's equatorial plane).

[0056] On internal paths, such as Figure 5 As shown, the inner surface stress at the end cap of the hydrogen storage cylinder under the design burst pressure of 95 MPa shows stress fluctuations at the end cap. However, it is clear that the most vulnerable area is the equatorial plane of the end cap.

[0057] Experimental Example 2 This experiment primarily investigates the degree of deformation of a hydrogen storage cylinder under self-tightening force.

[0058] Specifically, under zero pressure (0 MPa) after self-tightening, the maximum stress in the inner liner should not be less than 60% of the minimum guaranteed yield strength of the inner liner material, and should not be greater than 95%. The minimum guaranteed yield strength of the inner liner material is the value at which the inner liner does not become unstable after being subjected to self-tightening force.

[0059] Based on the axisymmetry of the gas cylinder, a 1 / 4 cylinder model was selected. Solid units were used for both the inner liner and the fiber composite layer, with layers defined according to the yarn laying angle, taking into account the thickness and angle variations of the fiber composite layer on the end cap. The spirally wound fiber utilization rate was 80%.

[0060] In the first process, the internal pressure of the gas cylinder increases from zero pressure (0 MPa) to the self-tightening pressure (76.0 MPa); Process two: reducing the pressure from the self-tightening pressure (76.0 MPa) to zero pressure (0 MPa); reducing the pressure from the self-tightening pressure (76.0 MPa) to zero pressure (0 MPa); Step 3: Increase the pressure from zero (0 MPa) to the nominal working pressure (35.0 MPa); Step 4: Increase the pressure from the nominal working pressure (35.0 MPa) to the allowable pressure (43.75 MPa); Step 5: Increase the pressure from the allowable pressure (43.75 MPa) to the hydrostatic test pressure (52.5 MPa); Table 1. Stress statistics of gas cylinders under various loading conditions

[0061] As shown in Table 1, and with reference to Figure 6 , Figure 7 and Figure 8Under different loading conditions (self-tightening pressure, hydrostatic test, and allowable pressure), the maximum stress distribution at different locations and in different directions of the inner liner shows that the maximum stress in the axial direction of the inner liner is the smallest compared to other directions, and reference... Figure 6 and Figure 7 Regardless of whether it's under allowable pressure or hydrostatic testing conditions, the equatorial surface of the hydrogen storage cylinder's end cap is the location of the highest stress. Therefore, it's necessary to measure its fatigue life to accurately and quickly predict the cylinder's service life. Figure 6 and Figure 7 The "S, S22" in the upper left corner, 'S' is used to characterize stress, and 'S22' is used to characterize the stress in the current coordinate system, that is, the axial stress of 214.4 MPa (under the water pressure test pressure).

[0062] like Figure 9 , Figure 10 and Figure 11 Referring to Table 1, under different loading conditions (self-tightening pressure, allowable pressure, and hydrostatic test), the Mises stress distribution of the aluminum liner shows that the stress is greatest or relatively high at the equatorial plane of the end cap. Both the Mises stress distribution of the aluminum liner and the axial stress distribution clearly demonstrate that the stress varies at different locations on the hydrogen storage cylinder, especially at the equatorial plane of the end cap, where the fatigue life also differs.

[0063] This experiment shows that there is a significant difference in strength between aluminum alloy inner liner and carbon fiber composite material. After the self-tightening process, the inner liner undergoes plastic deformation, while the stress and strength of the carbon fiber composite material are relatively small. Therefore, it is believed that the fatigue life of the carbon fiber composite material is much higher than that of the inner liner. Composite hydrogen storage cylinders often fail during use due to fatigue cracking or damage to the inner liner. The fatigue factor of composite hydrogen storage cylinders lies in the inner liner.

[0064] Example 3 Unlike the previous embodiments, this embodiment provides a hydrogen storage cylinder damage characteristic identification system, such as... Figure 12 As shown, a hydrogen storage cylinder damage characteristic identification system includes a data analysis module, which includes an electronic device. The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it enables the electronic device to implement a hydrogen storage cylinder damage characteristic identification method according to any of the above embodiments.

[0065] Specifically, such as Figure 13As shown, the electronic device may include: one or more processors 101, one or more input devices 102, one or more output devices 103, one or more memories 104, and a computer program stored in the memory 104 and executable on the processor. The processor 101, input devices 102, output devices 103, and memory 104 are interconnected via a bus 105. The memory 104 stores the computer program, which includes program instructions, and the processor 101 is configured to invoke the program instructions to execute the method steps described in the above method embodiments.

[0066] It should be understood that, in this embodiment, the processor 101 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0067] Input device 102 may include a keyboard, etc., and output device 103 may include a display (LCD, etc.), a speaker, etc.

[0068] The memory 104 may include read-only memory and random access memory, and provides instructions and data to the processor 101. A portion of the memory 104 may also include non-volatile random access memory. For example, the memory 104 may also store device type information.

[0069] In specific implementations, the processor 101, input device 102, and output device 103 described in the embodiments of the present invention can execute the implementation methods described in the relevant embodiments of the hydrogen storage cylinder damage characteristic identification method and system provided in the embodiments of the present invention, which will not be repeated here.

[0070] It should be noted that for a more detailed description of the electronic device's workflow and the implementation of a method for identifying damage characteristics of hydrogen storage cylinders, please refer to the aforementioned method implementation section, which will not be repeated here.

[0071] Example 4 Unlike the previous embodiments, the memory described in this embodiment should be interpreted broadly. It can be not only a hardware component in a computer system used for temporary data storage, but also a physical medium capable of storing digital information and being read by a computer. These media can be permanent or temporary, including but not limited to hard disks and solid-state drives.

[0072] Specifically, the memory can be an internal storage unit of the electronic device described in any of the embodiments, such as a system hard drive or memory. The memory can also be an external storage device of the system, such as a plug-in hard drive, SmartMediaCard (SMC), Secure Digital (SD) card, FlashCard, etc., equipped on the system. Furthermore, the memory can include both internal storage units and external storage devices. The memory is used to store the computer program and other programs and data required by the system. The memory can also be used to temporarily store data that has been output or will be output.

[0073] Storage devices include various media that can store program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0074] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, systems, and techniques have not been shown in detail so as not to obscure the understanding of this specification. In the description of this specification, references to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., mean that a specific feature, method, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this specification.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for identifying damage characteristics of hydrogen storage cylinders, characterized in that, include: S1: The threshold for collecting and storing damage data of hydrogen storage cylinder samples, as well as the threshold for low-cycle fatigue data of different regions on the hydrogen storage cylinder. S2: Arrange a sensor network for detection in various areas of the target hydrogen storage cylinder to collect the structural response data of the target hydrogen storage cylinder in real time; S3: If the structural response data is not lower than the damage data threshold, it is determined that the target hydrogen storage cylinder has suffered structural damage; S4: If no structural damage is detected, the real-time structural response data is partitioned according to the sensor distribution area, and the data of each area is compared with the fatigue data threshold of the corresponding area. If the structural response data of any area is not lower than the low-cycle fatigue data threshold of the corresponding area, it is determined that a fatigue structural crack has occurred in the area, and the target location of the fatigue structural crack in the area is further obtained. S5, predict the fatigue life of the target hydrogen storage cylinder based on the degree of fatigue structural cracks occurring at the target location.

2. The method for identifying damage characteristics of hydrogen storage cylinders according to claim 1, characterized in that, Before being put into production, the hydrogen storage cylinder sample was subjected to a hydrostatic test to obtain the maximum strain force of the hydrogen storage cylinder sample, and the maximum strain force was used as the damage data threshold. Before being put into production, the self-tightening pressure of the hydrogen storage cylinder sample is measured by a self-tightening process test, and the self-tightening pressure is used as the threshold for low-cycle fatigue data.

3. The method for identifying damage characteristics of hydrogen storage cylinders according to claim 2, characterized in that, According to thin film theory, the stress equation for the inner liner of the target hydrogen storage cylinder is: Strain includes axial stress and circumferential stress, where, This represents axial stress, with units of MPa. The value represents the circumferential stress, in MPa; a and b represent the major and minor semi-axis of the target hydrogen storage cylinder, respectively, in mm; h represents the wall thickness of the target hydrogen storage cylinder, in mm; x represents the distance from any point on the target hydrogen storage cylinder to the central axis of the target hydrogen storage cylinder, in mm; and P represents the pressure exerted on the target hydrogen storage cylinder, in MPa.

4. The method for identifying damage characteristics of hydrogen storage cylinders according to claim 1, characterized in that, The structural regions of a hydrogen storage cylinder include, in sequence, the equatorial plane of the end cap and the horizontal plane of the cylinder body; In S2, different numbers of sensors are arranged according to the stress of the inner liner. The number of sensors arranged in each area from most to least is as follows: the equatorial plane of the end cap and the horizontal plane of the cylinder. Among them, the sensors installed on the equatorial surface of the end cap are arranged in a ring, with the interval between two adjacent sensors not exceeding 200mm, which is used to accurately detect the structural response data of the equatorial surface of the end cap in the hydrogen storage cylinder that is subjected to the greatest shear force. The sensors installed on the horizontal plane of the cylinder are arranged in a dot matrix pattern, with a spacing of no less than 600mm between adjacent sensors.

5. The method for identifying damage characteristics of hydrogen storage cylinders according to claim 4, characterized in that, The ratio of the axial height of the end cap to the outer diameter of the inner liner should not exceed [value missing]. .

6. The method for identifying damage characteristics of hydrogen storage cylinders according to claim 4, characterized in that, In S5, the degree of fatigue structural cracks is calculated based on the target location; if the target location is located on the equatorial plane of the head, the fatigue damage within a first range around the target location is calculated based on the size and depth of the fatigue structural cracks at the target location. If the target location is on the horizontal plane of the cylinder, the fatigue damage in the second range around the target location is calculated based on the size and depth of the fatigue structural crack at the target location; wherein, the first range is larger than the second range.

7. The method for identifying damage characteristics of hydrogen storage cylinders according to claim 1, characterized in that, The fatigue life of the target hydrogen storage cylinder is predicted based on the degree of fatigue structural cracks occurring at the target location, y = -8126x + 15316, where y is the number of fillings, which is used to characterize the fatigue life of the target hydrogen storage cylinder, and x is the depth of the fatigue structural crack.

8. A system for identifying damage characteristics of hydrogen storage cylinders, characterized in that, The device includes a data analysis module, which includes an electronic device. The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it causes the electronic device to implement a method for identifying the damage characteristics of a hydrogen storage cylinder according to any one of claims 1-7.

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