Method and system for analyzing fatigue life of ultra-high pressure hydrogen storage container steel liner

Abstract

The application discloses a method and system for analyzing the fatigue life of a steel liner of an ultrahigh-pressure hydrogen storage container, and the method comprises the following steps: S1: using relevant equipment to detect and obtain the hydrogen environment fatigue basic parameters of the steel liner material under the ultrahigh-pressure hydrogen storage working condition, and the beneficial effects of the application are as follows: the application directly obtains the material basic parameters under a special hydrogen environment, and combines the actual working condition load spectrum and temperature field data, so that the precision of the model for the real service environment can be effectively improved, and by fully considering the key influencing factors such as hydrogen-induced fatigue degradation, ultrahigh-pressure alternating load and temperature fluctuation, and by accurately detecting the parameters under the hydrogen environment and correcting the stress, the problem that the existing method ignores the influence of the hydrogen environment and has large analysis deviation can be solved, and the accuracy of the fatigue life analysis can be greatly improved; and the influences of hydrogen-induced fatigue degradation, welding residual stress, thermal mechanical fatigue and corrosion pit morphology on crack propagation are comprehensively considered, so that the error caused by single factor analysis can be avoided.

Description

Technical Field

[0001] This invention relates to the field of ultra-high pressure hydrogen storage container technology, specifically to a method and system for analyzing the fatigue life of the steel inner liner of an ultra-high pressure hydrogen storage container. Background Technology

[0002] The steel inner liner of an ultra-high pressure hydrogen storage container is the inner metal structural component of the ultra-high pressure hydrogen storage container. It serves as the container's airtight barrier, shape support, and basic load-bearing layer. It is mainly used to store high-pressure hydrogen and is widely used in hydrogen energy storage and transportation, fuel cell vehicles, and other fields.

[0003] With the rapid development of the hydrogen energy industry, ultra-high pressure hydrogen storage containers, as core equipment for hydrogen storage and transportation, directly determine the prospects for the promotion of hydrogen energy applications based on their safety and reliability. The steel inner liner, as the core pressure-bearing component of the ultra-high pressure hydrogen storage container, operates under complex ultra-high pressure conditions for extended periods, making it highly susceptible to hydrogen-induced fatigue failure. The permeation and accumulation of hydrogen atoms leads to a decrease in the fatigue limit of the steel, inducing the initiation and propagation of hydrogen embrittlement cracks. Simultaneously, factors such as alternating internal pressure, temperature fluctuations, and the superposition of welding residual stress further exacerbate fatigue damage to the steel inner liner, potentially leading to leaks, explosions, and other safety accidents in severe cases.

[0004] During use, the service life of the steel liner of ultra-high pressure hydrogen storage containers is easily affected by various factors. Existing fatigue life analysis methods are mostly designed for conventional pressure vessels or ordinary steel, failing to fully consider the special characteristics of the ultra-high pressure hydrogen environment. This results in low analytical accuracy and poor specificity. Specifically, without establishing a precise detection system for fatigue parameters of the steel liner material under hydrogen conditions, it is difficult to accurately capture the hydrogen-induced fatigue degradation law. Furthermore, traditional fatigue life analysis methods, which are usually based on material parameters under air conditions, often ignore the deterioration effect of the hydrogen environment on the mechanical properties of steel. This leads to insufficient consideration of the coupling effect of welding residual stress, temperature cycling, and mechanical loads. Consequently, there is a lack of refined load spectrum compilation and multiaxial stress field solution methods for the actual working conditions of ultra-high pressure hydrogen storage. This results in a large deviation between the life prediction results and the actual service conditions, making it difficult to meet the safety assessment requirements of high-pressure hydrogen storage equipment throughout its entire life cycle. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for analyzing the fatigue life of the steel inner liner of an ultra-high pressure hydrogen storage container, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method and system for fatigue life analysis of the steel liner of an ultra-high pressure hydrogen storage container, the method comprising the following:

[0007] S1: Focusing on ultra-high pressure hydrogen storage conditions, using relevant equipment to detect and obtain basic parameters of hydrogen environment fatigue of steel inner liner materials;

[0008] S2: Based on the actual application scenarios of ultra-high pressure hydrogen storage containers, the load spectrum of actual working conditions for ultra-high pressure hydrogen storage is compiled and simplified.

[0009] S3: Based on the detection data, establish an overall three-dimensional model of the steel inner liner, and perform three-dimensional finite element modeling and fine mesh generation of the steel inner liner;

[0010] S4: Based on the established model, a suitable solution algorithm is used to solve the alternating stress field under multiple working conditions of the steel liner and identify dangerous parts;

[0011] S5: Under the special conditions of ultra-high pressure hydrogen environment, stress correction and fatigue damage equivalent conversion in hydrogen environment;

[0012] S6: Based on the basic parameters, load spectrum and corrected stress data obtained above, fatigue life calculation and damage accumulation analysis are performed;

[0013] S7: Conduct a safety check on the fatigue life of the steel inner liner and design an optimization scheme.

[0014] Preferably, step S1 includes the following:

[0015] S11: The fatigue parameters of the steel inner liner base material, weld and heat-affected zone will be detected and obtained, with ultra-high pressure hydrogen storage conditions as the core.

[0016] S12: Using relevant equipment such as the fatigue life test of steel inner liner, the mechanical properties, hydrogen embrittlement attenuation coefficient, hydrogen-induced fatigue SN curve, crack propagation threshold value and fracture toughness of steel under hydrogen environment are tested by using equipment such as high frequency fatigue testing machine, crack propagation rate testing system and metallographic microscope system.

[0017] S13: It mainly analyzes the key points of fatigue life assessment, fatigue crack initiation life, and fatigue crack propagation rate of the steel inner liner, and feeds the detected data back to the storage database to improve the parameter storage database.

[0018] Preferably, step S2 includes the following:

[0019] S21: Based on the actual application scenarios of ultra-high pressure hydrogen storage containers, the load spectrum of the steel inner liner is collected, statistically analyzed, and simplified.

[0020] S22: Through a multi-channel synchronous acquisition system, using instruments such as patch-type or extensometer-type sensors, accurately acquire data on hydrogen charging and discharging cycle pressure, start-stop impact load, and temperature fluctuation, and record key parameters such as alternating pressure amplitude, average stress, and stress ratio.

[0021] S23: Then, the loop counting method is used to statistically analyze the load amplitude distribution, analyze the load sequence effect, eliminate invalid load data, and simplify the compilation of a block program spectrum that fits the reality.

[0022] Preferably, step S3 includes the following:

[0023] S31: Based on the data obtained from the above steps, and in conjunction with the storage database, establish a three-dimensional model of the steel inner liner;

[0024] S32: Further refer to the pressure vessel design specifications and relevant testing standards to refine the grid division, and to densify the grid in areas prone to stress concentration, such as the inner wall, head transition fillets, and welded joints;

[0025] S33: By measuring and importing welding residual stress data through an X-ray stress analyzer or residual stress tester, the residual stress distribution generated by surface treatments such as shot peening is analyzed to ensure that the model can accurately simulate the actual stress state of the steel inner liner.

[0026] Preferably, step S4 includes the following:

[0027] S41: Based on the above steps, obtain the data, establish a finite element model, and use a suitable solution algorithm to calculate the alternating stress field of the steel inner liner during the ultra-high pressure hydrogen storage cycle, focusing on core analysis points such as multiaxial fatigue and thermomechanical fatigue.

[0028] S42: By using infrared thermal imager monitoring and combining the monitored surface temperature field data, the influence of temperature fluctuation on stress distribution is corrected, the thermomechanical fatigue effect of simultaneous temperature cycling and mechanical load is analyzed, the potential weak points of fatigue failure are identified, and the stress concentration factor is measured to compare the difference between the theoretical stress concentration factor and the fatigue notch factor.

[0029] Preferably, step S5 includes the following:

[0030] S51: Set up a special ultra-high pressure hydrogen environment, introduce a hydrogen-induced fatigue degradation coefficient, and correct the superposition effect of welding residual stress and fiber winding layer additional extrusion stress.

[0031] S52: In addition to the test results of the corrosion fatigue test device, the coupling effect of the test corrosion environment and alternating stress is studied, and the influence of corrosion pit morphology and depth and crack tip chemical changes on the fatigue performance of steel is analyzed. Then, the conventional stress is converted into the equivalent stress under hydrogen environment.

[0032] Preferably, step S6 includes the following:

[0033] S61: Collect and organize the data obtained through various methods such as equipment testing in the above steps, and then integrate the core points such as fatigue life assessment and fatigue damage accumulation. Using the Miner linear cumulative damage criterion, calculate the fatigue life of the steel inner liner.

[0034] S62: Then, the crack initiation life and crack propagation life are calculated in stages. By combining the crack initiation life with the hydrogen-induced fatigue SN curve, surface condition and slip zone observation results, the crack nucleation location and initiation cycle are statistically analyzed. Using the Paris formula and the parameters measured by the crack propagation rate test system, the crack length changes with the number of cycles is calculated, and the influence of overload on crack propagation is analyzed.

[0035] S63: Finally, integrate low-cycle fatigue and high-cycle fatigue damage, analyze the load interaction and residual strength decay law, obtain the total fatigue life of the steel inner liner, and at the same time carry out life dispersion analysis and failure probability statistics to verify the accuracy of the life prediction model.

[0036] Preferably, step S7 includes the following:

[0037] S71: Based on the data and results obtained from the above steps, integrate low-cycle fatigue and high-cycle fatigue damage, analyze the load interaction and residual strength decay law, obtain the total fatigue life of the steel inner liner, and at the same time carry out life dispersion analysis and failure probability statistics to verify the accuracy of the life prediction model.

[0038] S72: By employing statistical methods of failure probability, the lifetime dispersion is analyzed to verify the accuracy of the lifetime prediction model;

[0039] S73: Combining the microscopic mechanism of fatigue fracture, corrosion fatigue characteristics, and the effects of thermomechanical fatigue, the key reasons for insufficient service life are identified. Then, optimization solutions are proposed for the weak links to ensure that the fatigue life of the steel inner tank meets the actual application requirements. A complete analysis report is also provided to support the construction of a fatigue life prediction system for the entire life cycle of high-pressure hydrogen-contaminated equipment.

[0040] Preferably, the fatigue life analysis system for the steel inner liner of an ultra-high pressure hydrogen storage container includes: a control and analysis system, a data acquisition module, an equipment control module, a storage database, a load analysis module, a stress calculation module, a life assessment module, and a safety verification module. The control and analysis system is unidirectionally connected to the data acquisition module, and each data acquisition module is bidirectionally connected to the equipment control module and the storage database. The data acquisition module is unidirectionally connected to the load analysis module, the load analysis module is unidirectionally connected to the stress calculation module, the stress calculation module is unidirectionally connected to the life assessment module, and the life assessment module is unidirectionally connected to the safety verification module. The storage database is unidirectionally connected to the load analysis module, the stress calculation module, the life assessment module, and the safety verification module.

[0041] The acquisition module is used to accurately acquire the operating condition data of the ultra-high pressure hydrogen storage container in actual application scenarios;

[0042] The equipment control module is used to operate various professional testing equipment to obtain the basic fatigue parameters of the steel liner material in a hydrogen environment.

[0043] The storage database is used to improve the storage and management of parameters, providing data support for modeling and analysis.

[0044] Preferred options also include:

[0045] The load analysis module is used to perform statistical analysis and simplify the compilation of graphs from the collected raw operating data.

[0046] The stress calculation module is used to solve the alternating stress field of the steel liner under multiple working conditions and identify dangerous parts.

[0047] The life assessment module is used to calculate fatigue life and analyze damage accumulation by integrating various parameters.

[0048] The safety verification module is used to verify, perform probability analysis, and optimize the calculated fatigue life.

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] This invention directly obtains basic material parameters under a specific hydrogen environment and combines them with actual operating condition load spectrum and temperature field data, effectively improving the model's accuracy in real service environments. By fully considering key influencing factors such as hydrogen-induced fatigue degradation, ultra-high pressure alternating loads, and temperature fluctuations, and through precise parameter detection and stress correction under hydrogen conditions, it solves the problems of existing methods neglecting the influence of the hydrogen environment and having large analytical biases, significantly improving the accuracy of fatigue life analysis. Furthermore, by comprehensively considering the influence of hydrogen-induced fatigue degradation, welding residual stress, thermomechanical fatigue, and corrosion pit morphology on crack propagation, it avoids errors caused by single-factor analysis. Moreover, by refining the mesh and determining the stress concentration factor of key parts such as head transition fillets and welded joints, it can accurately identify potential fatigue failure weak points. Combined with multi-stage analysis and probabilistic statistics, it constructs a fatigue life prediction system supporting the entire life cycle of high-pressure hydrogen-contaminated equipment, thus providing a reliable basis for structural optimization and safety verification. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0052] Figure 2 This is a schematic diagram of the system framework of the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Please see Figures 1 to 2 This invention provides a technical solution: a method and system for fatigue life analysis of the steel inner liner of an ultra-high pressure hydrogen storage container, the method comprising the following:

[0055] S1: Focusing on ultra-high pressure hydrogen storage conditions, using relevant equipment to detect and obtain basic parameters of hydrogen environment fatigue of steel inner liner materials;

[0056] S2: Based on the actual application scenarios of ultra-high pressure hydrogen storage containers, the load spectrum of actual working conditions for ultra-high pressure hydrogen storage is compiled and simplified.

[0057] S3: Based on the detection data, establish an overall three-dimensional model of the steel inner liner, and perform three-dimensional finite element modeling and fine mesh generation of the steel inner liner;

[0058] S4: Based on the established model, a suitable solution algorithm is used to solve the alternating stress field under multiple working conditions of the steel liner and identify dangerous parts;

[0059] S5: Under the special conditions of ultra-high pressure hydrogen environment, stress correction and fatigue damage equivalent conversion in hydrogen environment;

[0060] S6: Based on the basic parameters, load spectrum and corrected stress data obtained above, fatigue life calculation and damage accumulation analysis are performed;

[0061] S7: Conduct a safety check on the fatigue life of the steel inner liner and design an optimization scheme.

[0062] Step S1 includes the following:

[0063] S11: The fatigue parameters of the steel inner liner base material, weld and heat-affected zone will be detected and obtained, with ultra-high pressure hydrogen storage conditions as the core.

[0064] S12: Using relevant equipment such as the fatigue life test of steel inner liner, the mechanical properties, hydrogen embrittlement attenuation coefficient, hydrogen-induced fatigue SN curve, crack propagation threshold value and fracture toughness of steel under hydrogen environment are tested by using equipment such as high frequency fatigue testing machine, crack propagation rate testing system and metallographic microscope system.

[0065] S13: It mainly analyzes the key points of fatigue life assessment, fatigue crack initiation life, and fatigue crack propagation rate of the steel inner liner, and feeds the detected data back to the storage database to improve the parameter storage database.

[0066] Step S2 includes the following:

[0067] S21: Based on the actual application scenarios of ultra-high pressure hydrogen storage containers, the load spectrum of the steel inner liner is collected, statistically analyzed, and simplified.

[0068] S22: Through a multi-channel synchronous acquisition system, using instruments such as patch-type or extensometer-type sensors, accurately acquire data on hydrogen charging and discharging cycle pressure, start-stop impact load, and temperature fluctuation, and record key parameters such as alternating pressure amplitude, average stress, and stress ratio.

[0069] S23: Then, the loop counting method is used to statistically analyze the load amplitude distribution, analyze the load sequence effect, eliminate invalid load data, and simplify the compilation of a block program spectrum that fits the reality.

[0070] Step S3 includes the following:

[0071] S31: Based on the data obtained from the above steps, and in conjunction with the storage database, establish a three-dimensional model of the steel inner liner;

[0072] S32: Further refer to the pressure vessel design specifications and relevant testing standards to refine the grid division, and to densify the grid in areas prone to stress concentration, such as the inner wall, head transition fillets, and welded joints;

[0073] S33: By measuring and importing welding residual stress data through an X-ray stress analyzer or residual stress tester, the residual stress distribution generated by surface treatments such as shot peening is analyzed to ensure that the model can accurately simulate the actual stress state of the steel inner liner.

[0074] Step S4 includes the following:

[0075] S41: Based on the above steps, obtain the data, establish a finite element model, and use a suitable solution algorithm to calculate the alternating stress field of the steel inner liner during the ultra-high pressure hydrogen storage cycle, focusing on core analysis points such as multiaxial fatigue and thermomechanical fatigue.

[0076] S42: By using infrared thermal imager monitoring and combining the monitored surface temperature field data, the influence of temperature fluctuation on stress distribution is corrected, the thermomechanical fatigue effect of simultaneous temperature cycling and mechanical load is analyzed, the potential weak points of fatigue failure are identified, and the stress concentration factor is measured to compare the difference between the theoretical stress concentration factor and the fatigue notch factor.

[0077] Step S5 includes the following:

[0078] S51: Set up a special ultra-high pressure hydrogen environment, introduce a hydrogen-induced fatigue degradation coefficient, and correct the superposition effect of welding residual stress and fiber winding layer additional extrusion stress.

[0079] S52: In addition to the test results of the corrosion fatigue test device, the coupling effect of the test corrosion environment and alternating stress is studied, and the influence of corrosion pit morphology and depth and crack tip chemical changes on the fatigue performance of steel is analyzed. Then, the conventional stress is converted into the equivalent stress under hydrogen environment.

[0080] Step S6 includes the following:

[0081] S61: Collect and organize the data obtained through various methods such as equipment testing in the above steps, and then integrate the core points such as fatigue life assessment and fatigue damage accumulation. Using the Miner linear cumulative damage criterion, calculate the fatigue life of the steel inner liner.

[0082] S62: Then, the crack initiation life and crack propagation life are calculated in stages. By combining the crack initiation life with the hydrogen-induced fatigue SN curve, surface condition and slip zone observation results, the crack nucleation location and initiation cycle are statistically analyzed. Using the Paris formula and the parameters measured by the crack propagation rate test system, the crack length changes with the number of cycles is calculated, and the influence of overload on crack propagation is analyzed.

[0083] S63: Finally, integrate low-cycle fatigue and high-cycle fatigue damage, analyze the load interaction and residual strength decay law, obtain the total fatigue life of the steel inner liner, and at the same time carry out life dispersion analysis and failure probability statistics to verify the accuracy of the life prediction model.

[0084] Step S7 includes the following:

[0085] S71: Based on the data and results obtained from the above steps, integrate low-cycle fatigue and high-cycle fatigue damage, analyze the load interaction and residual strength decay law, obtain the total fatigue life of the steel inner liner, and at the same time carry out life dispersion analysis and failure probability statistics to verify the accuracy of the life prediction model.

[0086] S72: By employing statistical methods of failure probability, the lifetime dispersion is analyzed to verify the accuracy of the lifetime prediction model;

[0087] S73: Combining the microscopic mechanism of fatigue fracture, corrosion fatigue characteristics, and the effects of thermomechanical fatigue, the key reasons for insufficient service life are identified. Then, optimization solutions are proposed for the weak links to ensure that the fatigue life of the steel inner tank meets the actual application requirements. A complete analysis report is also provided to support the construction of a fatigue life prediction system for the entire life cycle of high-pressure hydrogen-contaminated equipment.

[0088] The fatigue life analysis system for the steel inner liner of an ultra-high pressure hydrogen storage container includes: a control and analysis system, a data acquisition module, an equipment control module, a storage database, a load analysis module, a stress calculation module, a life assessment module, and a safety verification module. The control and analysis system is unidirectionally connected to the data acquisition module. Each data acquisition module is bidirectionally connected to the equipment control module and the storage database. Each data acquisition module is unidirectionally connected to the load analysis module, the load analysis module, the stress calculation module, the life assessment module, and the safety verification module. The storage database is unidirectionally connected to each of the load analysis module, the stress calculation module, the life assessment module, and the safety verification module.

[0089] The acquisition module is used to accurately acquire the operating condition data of the ultra-high pressure hydrogen storage container in actual application scenarios;

[0090] The equipment control module is used to operate various professional testing equipment to obtain the basic fatigue parameters of the steel liner material in a hydrogen environment.

[0091] The storage database is used to improve the storage and management of parameters, providing data support for modeling and analysis.

[0092] This also includes:

[0093] The load analysis module is used to perform statistical analysis and simplify the compilation of graphs from the collected raw operating data.

[0094] The stress calculation module is used to solve the alternating stress field of the steel liner under multiple working conditions and identify dangerous parts.

[0095] The life assessment module is used to calculate fatigue life and analyze damage accumulation by integrating various parameters.

[0096] The safety verification module is used to verify, perform probability analysis, and optimize the calculated fatigue life.

[0097] Specifically, when using this invention, the equipment control module operates various testing devices to collect the fatigue basic parameters (mechanical properties, hydrogen embrittlement coefficient, etc.) of the steel inner liner material in a hydrogen environment. Simultaneously, the acquisition module obtains data such as load and temperature under actual working conditions. All data is uploaded to a storage database for processing and storage, providing accurate support for subsequent analysis. The load analysis module retrieves working condition data from the storage database, performs statistical analysis, simplification, and compilation of the load spectrum, and outputs a suitable block program spectrum. The stress calculation module, based on this load spectrum and combined with a three-dimensional finite element model, solves the alternating stress field under multiple working conditions. It corrects for temperature effects using infrared thermal imager data, identifies critical areas and stress concentration regions, and completes stress correction and equivalent conversion under hydrogen conditions. The life assessment module retrieves material parameters from the storage database, the load spectrum from the load analysis module, and the corrected stress data from the stress calculation module. Using the Miner linear cumulative damage criterion, it calculates crack initiation and propagation life in stages, integrates low-cycle and high-cycle fatigue damage, obtains the total fatigue life, and verifies the accuracy of the results through life dispersion analysis and failure probability statistics. The life assessment results are verified through a safety verification module. Combining fracture surface analysis and corrosion fatigue characteristics, key causes of insufficient lifespan are identified, and targeted optimization solutions are proposed. The entire process is coordinated by a control and analysis system, ensuring collaborative operation of each module, standardized analysis procedures, and reliable results. Based on these modules, the following steps are implemented sequentially: Using ultra-high pressure hydrogen storage conditions as the core, basic parameters of hydrogen environment fatigue for the steel liner material are detected and acquired using relevant equipment; load spectra for actual ultra-high pressure hydrogen storage conditions are compiled and simplified, considering the actual application scenarios of ultra-high pressure hydrogen storage containers; a three-dimensional model of the steel liner is established based on the detection data, and three-dimensional finite element modeling and fine mesh generation are performed; based on the established model, appropriate solution algorithms are used to solve the alternating stress field of the steel liner under multiple operating conditions and identify hazardous areas; under the special conditions of ultra-high pressure hydrogen environment, hydrogen environment stress correction and fatigue damage equivalence conversion are performed; fatigue life calculation and damage accumulation analysis are conducted using the acquired basic parameters, load spectra, and corrected stress data; the fatigue life of the steel liner is verified for safety, and optimization solutions are designed.

[0098] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art 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 appended claims and their equivalents.

Claims

1. A method for fatigue life analysis of the steel inner liner of an ultra-high pressure hydrogen storage container, characterized in that, The method includes the following: S1: Focusing on ultra-high pressure hydrogen storage conditions, using relevant equipment to detect and obtain basic parameters of hydrogen environment fatigue of steel inner liner materials; S2: Based on the actual application scenarios of ultra-high pressure hydrogen storage containers, the load spectrum of actual working conditions for ultra-high pressure hydrogen storage is compiled and simplified. S3: Based on the detection data, establish an overall three-dimensional model of the steel inner liner, and perform three-dimensional finite element modeling and fine mesh generation of the steel inner liner; S4: Based on the established model, a suitable solution algorithm is used to solve the alternating stress field under multiple working conditions of the steel liner and identify dangerous parts; S5: Under the special conditions of ultra-high pressure hydrogen environment, stress correction and fatigue damage equivalent conversion in hydrogen environment; S6: Based on the basic parameters, load spectrum and corrected stress data obtained above, fatigue life calculation and damage accumulation analysis are performed; S7: Conduct a safety check on the fatigue life of the steel inner liner and design an optimization scheme.

2. The fatigue life analysis method for the steel liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S1 includes the following: S11: The fatigue parameters of the steel inner liner base material, weld and heat-affected zone will be detected and obtained, with ultra-high pressure hydrogen storage conditions as the core. S12: Using relevant equipment such as the fatigue life test of steel inner liner, the mechanical properties, hydrogen embrittlement attenuation coefficient, hydrogen-induced fatigue SN curve, crack propagation threshold value and fracture toughness of steel under hydrogen environment are tested by using equipment such as high frequency fatigue testing machine, crack propagation rate testing system and metallographic microscope system. S13: It mainly analyzes the key points of fatigue life assessment, fatigue crack initiation life, and fatigue crack propagation rate of the steel inner liner, and feeds the detected data back to the storage database to improve the parameter storage database.

3. The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S2 includes the following: S21: Based on the actual application scenarios of ultra-high pressure hydrogen storage containers, the load spectrum of the steel inner liner is collected, statistically analyzed, and simplified. S22: Through a multi-channel synchronous acquisition system, using instruments such as patch-type or extensometer-type sensors, accurately acquire data on hydrogen charging and discharging cycle pressure, start-stop impact load, and temperature fluctuation, and record key parameters such as alternating pressure amplitude, average stress, and stress ratio. S23: Then, the loop counting method is used to statistically analyze the load amplitude distribution, analyze the load sequence effect, eliminate invalid load data, and simplify the compilation of a block program spectrum that fits the reality.

4. The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S3 includes the following: S31: Based on the data obtained from the above steps, and in conjunction with the storage database, establish a three-dimensional model of the steel inner liner; S32: Further refer to the pressure vessel design specifications and relevant testing standards to refine the grid division, and to densify the grid in areas prone to stress concentration, such as the inner wall, head transition fillets, and welded joints; S33: By measuring and importing welding residual stress data through an X-ray stress analyzer or residual stress tester, the residual stress distribution generated by surface treatments such as shot peening is analyzed to ensure that the model can accurately simulate the actual stress state of the steel inner liner.

5. The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S4 includes the following: S41: Based on the above steps, obtain the data, establish a finite element model, and use a suitable solution algorithm to calculate the alternating stress field of the steel inner liner during the ultra-high pressure hydrogen storage cycle, focusing on core analysis points such as multiaxial fatigue and thermomechanical fatigue. S42: By using infrared thermal imager monitoring and combining the monitored surface temperature field data, the influence of temperature fluctuation on stress distribution is corrected, the thermomechanical fatigue effect of simultaneous temperature cycling and mechanical load is analyzed, the potential weak points of fatigue failure are identified, and the stress concentration factor is measured to compare the difference between the theoretical stress concentration factor and the fatigue notch factor.

6. The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S5 includes the following: S51: Set up a special ultra-high pressure hydrogen environment, introduce a hydrogen-induced fatigue degradation coefficient, and correct the superposition effect of welding residual stress and fiber winding layer additional extrusion stress. S52: In addition to the test results of the corrosion fatigue test device, the coupling effect of the test corrosion environment and alternating stress is studied, and the influence of corrosion pit morphology and depth and crack tip chemical changes on the fatigue performance of steel is analyzed. Then, the conventional stress is converted into the equivalent stress under hydrogen environment.

7. The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S6 includes the following: S61: Collect and organize the data obtained through various methods such as equipment testing in the above steps, and then integrate the core points such as fatigue life assessment and fatigue damage accumulation. Using the Miner linear cumulative damage criterion, calculate the fatigue life of the steel inner liner. S62: Then, the crack initiation life and crack propagation life are calculated in stages. By combining the crack initiation life with the hydrogen-induced fatigue SN curve, surface condition and slip zone observation results, the crack nucleation location and initiation cycle are statistically analyzed. Using the Paris formula and the parameters measured by the crack propagation rate test system, the crack length changes with the number of cycles is calculated, and the influence of overload on crack propagation is analyzed. S63: Finally, integrate low-cycle fatigue and high-cycle fatigue damage, analyze the load interaction and residual strength decay law, obtain the total fatigue life of the steel inner liner, and at the same time carry out life dispersion analysis and failure probability statistics to verify the accuracy of the life prediction model.

8. The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container according to claim 1, characterized in that: Step S7 includes the following: S71: Based on the data and results obtained from the above steps, integrate low-cycle fatigue and high-cycle fatigue damage, analyze the load interaction and residual strength decay law, obtain the total fatigue life of the steel inner liner, and at the same time carry out life dispersion analysis and failure probability statistics to verify the accuracy of the life prediction model. S72: By employing statistical methods of failure probability, the lifetime dispersion is analyzed to verify the accuracy of the lifetime prediction model; S73: Combining the microscopic mechanism of fatigue fracture, corrosion fatigue characteristics, and the effects of thermomechanical fatigue, the key reasons for insufficient service life are identified. Then, optimization solutions are proposed for the weak links to ensure that the fatigue life of the steel inner tank meets the actual application requirements. A complete analysis report is also provided to support the construction of a fatigue life prediction system for the entire life cycle of high-pressure hydrogen-contaminated equipment.

9. A fatigue life analysis system for the steel inner liner of an ultra-high pressure hydrogen storage container, characterized in that: The fatigue life analysis method for the steel inner liner of an ultra-high pressure hydrogen storage container as described in any one of claims 1-8 includes: a control and analysis system, an acquisition module, an equipment control module, a storage database, a load analysis module, a stress calculation module, a life assessment module, and a safety verification module. The control and analysis system is unidirectionally connected to the acquisition module, the acquisition modules are bidirectionally connected to the equipment control module and the storage database, the acquisition module is unidirectionally connected to the load analysis module, the load analysis module is unidirectionally connected to the stress calculation module, the stress calculation module is unidirectionally connected to the life assessment module, the life assessment module is unidirectionally connected to the safety verification module, and the storage database is unidirectionally connected to the load analysis module, the stress calculation module, the life assessment module, and the safety verification module. The acquisition module is used to accurately acquire the operating condition data of the ultra-high pressure hydrogen storage container in actual application scenarios; The equipment control module is used to operate various professional testing equipment to obtain the basic fatigue parameters of the steel liner material in a hydrogen environment. The storage database is used to improve the storage and management of parameters, providing data support for modeling and analysis.

10. The fatigue life analysis system for the steel liner of an ultra-high pressure hydrogen storage container according to claim 9, characterized in that: Also includes: The load analysis module is used to perform statistical analysis and simplify the compilation of graphs from the collected raw operating data. The stress calculation module is used to solve the alternating stress field of the steel liner under multiple working conditions and identify dangerous parts. The life assessment module is used to calculate fatigue life and analyze damage accumulation by integrating various parameters. The safety verification module is used to verify, perform probability analysis, and optimize the calculated fatigue life.

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