Finite element analysis method for vibration fatigue of vertical low-temperature heat-insulation gas cylinder system

Abstract

The invention discloses a vibration fatigue finite element analysis method for a vertical low-temperature heat-insulation gas cylinder system. The method comprises the following steps: constructing a three-dimensional model of the vertical low-temperature heat-insulation gas cylinder system by utilizing modeling software; respectively importing the three-dimensional models of the vertical low-temperature heat-insulation gas cylinder system into ANSYS finite element analysis software, setting material attributes according to reality, and performing contact and grid division; setting load and constraint according to the actual vibration test working condition, and calculating the inherent frequency of the vertical low-temperature heat-insulation gas cylinder system in the ANSYS modal analysis module; converting the actually measured pavement unevenness power spectral density or the national standard pavement unevenness power spectral density into a random vibration load, and calculating a random vibration dynamic response by combining the inherent frequency obtained by modal analysis; the random vibration fatigue life of the low-temperature heat-insulation gas cylinder system is determined by combining an S-N curve of a material and a fatigue failure criterion, and theoretical guidance is provided for vibration characteristic research and safety application of the vertical low-temperature heat-insulation gas cylinder system.

Description

Technical Field

[0001] This invention relates to the field of vibration characteristic analysis of industrial gas cylinders, and more specifically, to a vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system. Background Technology

[0002] Cryogenic insulated gas cylinders are capable of storing and transporting cryogenic liquids such as liquid oxygen, liquid nitrogen, and liquid argon under pressure. Compared to ordinary gas cylinders, they have a more complex structural design and higher production costs. During vehicle transportation, cryogenic insulated gas cylinders are subjected to continuous low-amplitude, high-frequency vibrations, which may lead to vibration fatigue failure and safety accidents. To effectively prevent the risk of vibration fatigue failure, vibration testing must be conducted during the product development and design phase to comprehensively evaluate the overall vibration fatigue life of the gas cylinder. However, it is worth noting that if vibration testing reveals failure, it will mean that additional time and funds will be needed to redesign and retest the gas cylinder.

[0003] The development of vehicle-mounted cryogenic insulated gas cylinders is still in its early stages, and there is limited research on their vibration characteristics. Hao Chaoyang et al. (Hao Chaoyang, Ding Hua, Li Muze, et al. Structural strength and vibration fatigue analysis of vehicle-mounted cryogenic insulated gas cylinders [J]. Cryogenics and Superconductivity, 2024, 52(06): 58-64+102.) studied the strength and fatigue of a horizontal vehicle-mounted cryogenic insulated gas cylinder filled with liquid hydrogen under braking conditions based on ANSYS; Chen Yuqiu (Chen Yuqiu. Structural optimization and fatigue life study of vehicle-mounted cryogenic insulated LNG cylinders based on stress analysis [J]. Cryogenic Engineering, 2022, 4: 62-69.) calculated the fatigue life of a horizontal vehicle-mounted LNG cylinder under impact load based on stress analysis. Mir et al. (MIR O, SHAKOURI M, Ashory M R. Gas pressure and density effects on vibration of cylindrical pressure vessels: analytical, numerical and experimental analysis[J]. SN Applied Sciences, 2020, 2(1)) studied the natural frequencies and mode shapes of gas cylinders under different gases and internal pressures using modal tests and finite element software, respectively.

[0004] Current research mainly focuses on horizontal gas cylinders considering strap constraints, while studies on the vibration characteristics of vertical cryogenic insulated gas cylinders, especially under special vertical external frame constraints, are relatively insufficient. However, vertical cryogenic insulated gas cylinders are widely used in transportation processes; for example, live fish transport vehicles need to be equipped with vertical liquid oxygen cylinders to supply oxygen to the fish. To ensure the transportation safety of vertical cryogenic insulated gas cylinder systems in such vehicles, this invention proposes a vibration fatigue finite element analysis method for vertical cryogenic insulated gas cylinder systems, providing a reference for the structural design and safe operation of gas cylinders. Summary of the Invention

[0005] The purpose of this invention is to construct a vertical cryogenic insulated gas cylinder system structure considering the external frame, and to analyze the vibration fatigue characteristics of this vertical cryogenic insulated gas cylinder system using the finite element analysis method. In order to solve the fatigue failure problem that may occur during transportation and use, a vibration fatigue finite element analysis method for vertical cryogenic insulated gas cylinder system is proposed.

[0006] The present invention is achieved by at least one of the following technical solutions.

[0007] A finite element method for vibration fatigue analysis of a vertical cryogenic insulated gas cylinder system includes the following steps:

[0008] S1. Construct a three-dimensional model of a vertical cryogenic insulated gas cylinder system with different inner wall thicknesses using three-dimensional modeling software.

[0009] S2. Import the three-dimensional model of the vertical cryogenic insulated gas cylinder system into the finite element analysis software, set the material properties and contact according to the actual situation, and perform mesh generation to obtain the finite element model of the vertical cryogenic insulated gas cylinder system.

[0010] S3. Set loads and constraints according to the actual vibration test conditions, and calculate the first multiple natural frequencies of the vertical cryogenic insulated gas cylinder system in the modal analysis module of the finite element analysis software.

[0011] S4. Input the measured power spectral density of road surface roughness or the power spectral density of the national standard into the finite element analysis software, convert the power spectral density into random vibration load, and calculate the random vibration dynamic response by combining the natural frequency obtained from modal analysis.

[0012] S5. Determine the random vibration fatigue damage of the vertical cryogenic insulated gas cylinder system by combining the SN curve of the material and the fatigue failure criterion.

[0013] Furthermore, the vertical cryogenic insulated gas cylinder system in step S1 includes a cryogenic insulated gas cylinder and a cylinder frame for supporting the cryogenic insulated gas cylinder.

[0014] Furthermore, the three-dimensional model of the cryogenic insulated gas cylinder includes the upper and lower end caps of the outer shell, the outer shell cylinder, the upper and lower end caps of the inner liner, the inner liner cylinder, the upper and lower supports, the vibration isolation plate, the positioning cylinder, and the positioning sleeve;

[0015] The three-dimensional model of the gas cylinder frame includes a top component and a bottom component. The top component contains an axial support, and the bottom component contains radial supports and mounting holes.

[0016] Furthermore, the material properties in step S2 include density, elastic modulus, and Poisson's ratio. The virtual mass method is used to equate the 50% liquid nitrogen filling the cryogenic insulated gas cylinder to the cryogenic insulated gas cylinder.

[0017] Furthermore, the calculation formula for the virtual mass method is as follows:

[0018]

[0019] Where, ρ e ρ represents the equivalent density. l ρ represents the density of the filling medium. in V represents the density of the gas cylinder liner, and m represents the effective volume of the gas cylinder. in This indicates the mass of the gas cylinder's inner liner.

[0020] Furthermore, the contact settings in step S2 include: a NoSeparation contact between the positioning cylinder and the positioning sleeve; a Frictional contact between the vibration isolation plate and the lower end cap of the outer shell; and a Bonded contact for all other components.

[0021] Meshing was performed using the ANSYS Mesh module of the ANSYS finite element analysis software. The HexDominant method was used to mesh the inner liner and outer shell of the gas cylinder, while the remaining parts were automatically meshed. The mesh element type was Solid186 solid element.

[0022] Furthermore, the loads and constraints in step S3 are set through the Static Structural module, the nominal working pressure is evenly distributed on the inner liner of the gas cylinder, gravitational acceleration is added in the negative Y-axis direction, and fixed support is set in the mounting holes at the bottom of the gas cylinder frame according to the actual vibration test conditions.

[0023] The natural frequencies were determined using the Modal module of ANSYS, where the frequency extraction order was set, and the BlockLanczos method was used to solve the modes.

[0024] Furthermore, the random vibration response in step S4 is performed using the Random Vibration module of ANSYS. The random vibration load is calculated and converted based on the acceleration power spectral density caused by road surface unevenness. The acceleration power spectral densities in the X, Y, and Z directions are input into the Random Vibration module as random vibration load spectra, and the mechanical response of the vertical cryogenic insulated gas cylinder system under random vibration load is calculated.

[0025] Furthermore, the formula for calculating the random vibration fatigue damage of the vertical cryogenic insulated gas cylinder system in step S5 is as follows:

[0026]

[0027] Where D represents random vibration fatigue damage; n 1σ n 2σ n 3σ These represent the actual number of cycles for the material within the stress ranges of -1σ to 1σ, -2σ to 2σ, and -3σ to 3σ, respectively, with values ​​of 0.6827 N, 0.2718 N, and 0.0455 N, where N is the fatigue life. 1σ N 2σ N 3σ These represent the permissible number of cycles corresponding to the 1σ, 2σ, and 3σ stress levels obtained based on the material's SN curve; when the random vibration fatigue damage D = 1 in the vertical cryogenic insulated gas cylinder system, it indicates that the system has experienced fatigue failure. The formula for calculating the fatigue life N at this point is as follows:

[0028]

[0029] A computer device according to the present invention includes: a memory and a processor, and a computer program stored in the memory, which, when executed on the processor, implements the method.

[0030] The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system proposed in this invention has the following advantages compared with existing technologies:

[0031] This invention proposes a vertical gas cylinder outer frame and considers vertical cryogenic insulated gas cylinders with different inner wall thicknesses and the outer frame as a whole system. This approach not only overcomes the limitations of previous studies that only focused on a single gas cylinder without considering external constraint components or simplified models, but also more closely reflects actual working conditions, making the analysis results more accurate and comprehensive, and enabling a comprehensive analysis of the system composed of cryogenic insulated gas cylinders and outer frames.

[0032] This invention utilizes the finite element method, which can efficiently and accurately determine the natural frequencies and vibration fatigue life of a vertical cryogenic insulated gas cylinder system. Natural frequencies and vibration fatigue life are crucial parameters for evaluating the vibration characteristics of a structure, directly impacting the system's stability and safety under external excitations. This is particularly important in dynamic environments such as vehicle transportation, where vertical cryogenic insulated gas cylinder systems may be subjected to various complex excitations. Precise calculations can accurately identify potential resonance and fatigue failure risks, providing strong support for structural optimization.

[0033] The invention has a wide range of applications, not only applicable to the structural optimization design of vertical cryogenic insulated gas cylinder systems, but also providing a reference for the revision of relevant standards.

[0034] In summary, the vibration fatigue finite element analysis method for vertical cryogenic insulated gas cylinder systems proposed in this invention can improve the accuracy and comprehensiveness of the analysis, and can provide a reference for the structural optimization design of vertical cryogenic insulated gas cylinder systems and the revision of relevant standards, so as to prevent structural resonance failure and fatigue failure and ensure the safe transportation of gas cylinders. Attached Figure Description

[0035] Figure 1 This is a flowchart of the vibration fatigue finite element analysis method for the vertical cryogenic insulated gas cylinder system in this embodiment.

[0036] Figure 2 This is a schematic diagram of a three-dimensional model of the vertical cryogenic insulated gas cylinder system in this embodiment;

[0037] Figure 3 This is a schematic diagram of the finite element model mesh generation of the vertical cryogenic insulated gas cylinder system in this embodiment;

[0038] Figure 4 This is a schematic diagram of the natural frequency of the vertical cryogenic insulated gas cylinder system in this embodiment.

[0039] Figure 5 This is a schematic diagram of the power spectral density of random vibration acceleration caused by road surface unevenness in this embodiment;

[0040] Figure 6 This is a cross-sectional cloud diagram of the random vibration fatigue life of the vertical cryogenic insulated gas cylinder system in this embodiment.

[0041] Specific Implementation Cases

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, but the implementation of the present invention is not limited thereto. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0043] like Figure 1 As shown in the figure, this embodiment provides a vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system, including the following steps:

[0044] S1, such as Figure 2 As shown, a three-dimensional model of a vertical cryogenic insulated gas cylinder system was constructed using SOLIDWORKS software. The model includes a cryogenic insulated gas cylinder and a cylinder frame. The three-dimensional model of the cryogenic insulated gas cylinder includes upper and lower end caps of the outer shell, outer shell cylinder, upper and lower end caps of the inner liner, inner liner cylinder, upper and lower supports, vibration isolation plate, positioning cylinder, and positioning sleeve. The three-dimensional model of the cylinder frame includes a top component and a bottom component. The top component includes an axial support, and the bottom component includes radial support and mounting holes. The three-dimensional model of the vertical cryogenic insulated gas cylinder system ignores non-pressure-bearing components such as valves and piping systems, as well as welds and chamfers.

[0045] As one embodiment, the main dimensions of the cryogenic insulated gas cylinder in this embodiment include: a nominal diameter of 450mm for the inner liner, a length of 1188mm for the inner cylinder, a nominal diameter of 504mm for the outer shell, and a length of 1348mm for the outer cylinder; the specifications of the gas cylinder frame are 600mm×600mm×1500mm.

[0046] S2. Constructing the finite element model of the vertical cryogenic insulated gas cylinder system: Import the three-dimensional model of the vertical cryogenic insulated gas cylinder system into the finite element analysis software, set the material properties and contact according to the actual situation, and perform mesh generation to obtain the finite element model of the vertical cryogenic insulated gas cylinder system.

[0047] As one embodiment, the material properties include density, elastic modulus, and Poisson's ratio, as shown in Table 1. The inner and outer liner of the cryogenic insulated gas cylinder are both made of austenitic stainless steel 06Cr19Ni10 (S30408), the main body of the gas cylinder frame is made of carbon structural steel (Q235-B), and the vibration isolation plate is made of rubber material.

[0048] Table 1 Material Properties of Vertical Cryogenic Insulated Gas Cylinder System

[0049] structure Material <![CDATA[Density / kg·m -3 > Elastic modulus / GPa Poisson's ratio Cryogenic Insulated Gas Cylinder S30408 7930 193 0.29 Isolation board rubber 1500 0.08 0.48 Cylinder frame Q235-B 7850 210 0.274

[0050] The virtual mass method is used to represent the 50% liquid nitrogen filling the gas cylinder as equivalent to the lower end cap and lower half of the inner liner. This method ignores the influence of liquid sloshing and reduces the solid-liquid coupling problem to a simple solid dynamics problem, greatly simplifying the solution process. In this embodiment, the density of liquid nitrogen is 810 kg·m³. -3 The formula for calculating virtual mass is as follows:

[0051]

[0052] Where, ρ e ρ represents the equivalent density.l ρ represents the density of the filling medium. in V represents the density of the gas cylinder liner, and m represents the effective volume of the gas cylinder. in This indicates the mass of the gas cylinder's inner liner.

[0053] The contact settings are as follows: the positioning cylinder of the lower support and the positioning sleeve use "No Separation" contact; the vibration isolation plate and the lower end cap of the outer shell use "Frictional" contact; and the connections of all other components use "Bonded" contact.

[0054] The mesh generation was performed using the ANSYS Mesh module, employing the Hex Dominant method to mesh the inner and outer shell of the gas cylinder. The remaining parts were automatically meshed. The mesh element type was Solid186. Figure 3 The diagram shown is a schematic of the grid division.

[0055] S3. Set loads and constraints according to the actual vibration test conditions, and calculate the first 20 natural frequencies of the vertical cryogenic insulated gas cylinder system in the modal analysis module of the finite element analysis software.

[0056] The loads and constraints are set using the Static Structural module. A nominal working pressure is uniformly distributed across the inner liner of the gas cylinder, i.e., a pressure of 2.3 MPa is added to the surface of the inner liner. Gravitational acceleration is also added in the negative Y-axis direction, i.e., the Y-axis acceleration is set to -9.81 m / s². 2 Then, the results from the Static Structural module are loaded into the Modal module in the form of prestress for modal analysis. Fixed supports are installed at the mounting holes at the bottom of the gas cylinder frame according to the actual vibration test conditions; specifically, "Fixed Support" constraints are added at two mounting holes on each side of the bottom.

[0057] The natural frequencies are calculated using ANSYS's Modal module. As an example, in "Analysis Settings," the "Max Modes to Find" value is entered as 20, meaning the frequency extraction order is the first 20 orders. In "Solver Type," the "Direct" method is selected, which is equivalent to the classic Block Lanczos method for solving modes. Right-clicking "Solution" and then clicking "Solve" performs the calculation. The calculation results, i.e., the first 20 natural frequencies, are displayed in the "Tabular Data" window. (The summary is as follows...) Figure 4 As shown.

[0058] S4. Input the measured power spectral density or national standard power spectral density of the measured road surface roughness into the finite element analysis software, convert the power spectral density into random vibration load, and calculate the random vibration dynamic response by combining it with the natural frequency obtained from modal analysis.

[0059] As one embodiment, the vibration environment of highway trucks in the national military standard GJB150.16A-2009 "Laboratory Environmental Test Methods for Military Equipment Part 16: Vibration Test" is adopted. Figure 5 As shown. In the Random Vibration module, input the acceleration power spectral density in three directions respectively, and convert the acceleration power spectral density into random vibration load to calculate the random vibration dynamic response.

[0060] S5. Determine the random vibration fatigue damage of the vertical cryogenic insulated gas cylinder system by combining the SN curve of the material and the fatigue failure criterion.

[0061] The formula for calculating random vibration fatigue damage is as follows:

[0062]

[0063] Where D represents random vibration fatigue damage; n 1σ n 2σ n 3σ These represent the actual number of cycles for the material within the stress ranges of -1σ to 1σ, -2σ to 2σ, and -3σ to 3σ, respectively, with values ​​of 0.6827 N, 0.2718 N, and 0.0455 N, where N is the fatigue life (cycles). 1σ N 2σ N 3σ These represent the permissible number of cycles corresponding to the 1σ, 2σ, and 3σ stress levels obtained from the material's SN curve, respectively.

[0064] As one embodiment, the maximum equivalent stresses of the cryogenic insulated gas cylinder system in this embodiment under random vibrations caused by road surface unevenness are 89.99 MPa, 121.98 MPa, and 178.05 MPa for stress levels 1σ, 2σ, and 3σ, respectively. Based on the material's S / N curve, the permissible number of cycles for the cryogenic insulated gas cylinder system in this embodiment at stress levels 1σ, 2σ, and 3σ are 6.11 × 10⁻⁶. 5 1.81×10 5 4.23×10 4 :

[0065] The fatigue failure criterion is that fatigue failure occurs when fatigue damage D = 1. Therefore, the formula for calculating the random vibration fatigue life N of the cryogenic insulated gas cylinder is as follows:

[0066]

[0067] As one embodiment, the maximum fatigue life N of the cryogenic insulated gas cylinder system in this embodiment is calculated to be 2.63 × 10⁻⁶ according to equation (3). 5 Fatigue life cloud map as follows Figure 6 As shown, the areas where the upper and lower supports of the gas cylinder liner connect to the cylinder body have the shortest fatigue life, making them prone to fatigue damage. According to the national standard GB / T 24159-2022 "Welded Insulated Gas Cylinders," the fatigue cycle count should be less than 430,500 cycles. Therefore, the fatigue life of this embodiment does not meet the national standard requirement.

[0068] This invention has certain universality for vibration fatigue calculation of vertical cryogenic insulated gas cylinder systems. By changing the filling medium, filling volume, cylinder length-to-diameter ratio, inner liner wall thickness, and outer frame constraint method, more natural frequencies and resonant frequencies under working conditions can be obtained, thereby calculating the fatigue life of the vertical cryogenic insulated gas cylinder system and providing a certain reference for the structural design and safe application of vertical cryogenic insulated gas cylinders.

[0069] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A finite element analysis method for vibration fatigue of a vertical cryogenic insulated gas cylinder system, characterized in that, Includes the following steps: S1. Construct a three-dimensional model of a vertical cryogenic insulated gas cylinder system with different inner wall thicknesses using three-dimensional modeling software. S2. Import the three-dimensional model of the vertical cryogenic insulated gas cylinder system into the finite element analysis software, set the material properties and contact according to the actual situation, and perform mesh generation to obtain the finite element model of the vertical cryogenic insulated gas cylinder system. S3. Set loads and constraints according to the actual vibration test conditions, and calculate the first multiple natural frequencies of the vertical cryogenic insulated gas cylinder system in the modal analysis module of the finite element analysis software. S4. Input the measured power spectral density of road surface roughness or the power spectral density of the national standard into the finite element analysis software, convert the power spectral density into random vibration load, and calculate the random vibration dynamic response by combining the natural frequency obtained from modal analysis. S5. Determine the random vibration fatigue damage of the vertical cryogenic insulated gas cylinder system by combining the SN curve of the material and the fatigue failure criterion.

2. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 1, characterized in that, The vertical cryogenic insulated gas cylinder system in step S1 includes a cryogenic insulated gas cylinder and a cylinder frame for supporting the cryogenic insulated gas cylinder.

3. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 2, characterized in that, The three-dimensional model of the cryogenic insulated gas cylinder includes the upper and lower end caps of the outer shell, the outer shell cylinder, the upper and lower end caps of the inner liner, the inner liner cylinder, the upper and lower supports, the vibration isolation plate, the positioning cylinder, and the positioning sleeve; The three-dimensional model of the gas cylinder frame includes a top component and a bottom component. The top component contains an axial support, and the bottom component contains radial supports and mounting holes.

4. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 1, characterized in that, The material properties in step S2 include density, elastic modulus, and Poisson's ratio. The virtual mass method is used to equate the 50% liquid nitrogen filling the cryogenic insulation cylinder to the inside of the cryogenic insulation cylinder.

5. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 4, characterized in that, The calculation formula for the virtual mass method is as follows: Where, ρ e ρ represents the equivalent density. l ρ represents the density of the filling medium. in V represents the density of the gas cylinder liner, and m represents the effective volume of the gas cylinder. in This indicates the mass of the gas cylinder's inner liner.

6. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 2, characterized in that, The contact settings in step S2 include: No Separation contact between the positioning cylinder and the positioning sleeve; Frictional contact between the vibration isolation plate and the lower end cap of the outer shell; and Bonded contact for all other components. Meshing was performed using the ANSYS Mesh module of the ANSYS finite element analysis software. The Hex Dominant method was used to mesh the inner liner and outer shell of the gas cylinder, while the remaining parts were automatically meshed. The mesh element type was Solid186 solid element.

7. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 3, characterized in that, The loads and constraints in step S3 are set through the Static Structural module. The nominal working pressure is evenly distributed on the inner liner of the gas cylinder, and gravitational acceleration is added in the negative Y-axis direction. Fixed support is set in the mounting holes at the bottom of the gas cylinder frame according to the actual vibration test conditions. The natural frequencies were determined using the Modal module of ANSYS, where the frequency extraction order was set, and the Block Lanczos method was used to solve the modes.

8. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 1, characterized in that, The random vibration response in step S4 is performed using the Random Vibration module of ANSYS. The random vibration load is calculated and converted based on the acceleration power spectral density caused by road surface unevenness. The acceleration power spectral densities in the X, Y, and Z directions are input into the Random Vibration module as random vibration load spectra, and the mechanical response of the vertical cryogenic insulated gas cylinder system under random vibration load is calculated.

9. The vibration fatigue finite element analysis method for a vertical cryogenic insulated gas cylinder system according to claim 1, characterized in that, The formula for calculating random vibration fatigue damage of the vertical cryogenic insulated gas cylinder system in step S5 is as follows: Where D represents random vibration fatigue damage; n 1σ n 2σ n 3σ These represent the actual number of cycles for the material within the stress ranges of -1σ to 1σ, -2σ to 2σ, and -3σ to 3σ, respectively, with values ​​of 0.6827 N, 0.2718 N, and 0.0455 N, where N is the fatigue life. 1σ N 2σ N 3σ These represent the permissible number of cycles corresponding to the 1σ, 2σ, and 3σ stress levels obtained based on the material's SN curve; when the random vibration fatigue damage D = 1 in the vertical cryogenic insulated gas cylinder system, it indicates that the system has experienced fatigue failure. The formula for calculating the fatigue life N at this point is as follows:

10. A computer device, characterized in that, include: A memory and a processor, and a computer program stored in the memory, which, when executed on the processor, implements the method as described in any one of claims 1 to 9.

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