Fatigue life evaluation method, system, medium and equipment for thin-wall seamless lining gas cylinder

Abstract

The invention provides a method, a system, a medium and equipment for evaluating the fatigue life of a thin-wall seamless lining composite material gas cylinder for spaceflight. The method comprises the following steps: acquiring the geometric dimension, winding parameters, material parameters, total load, fatigue alternating pressure and fatigue alternating times of a gas cylinder to be evaluated; determining the diameter deformation of the gas cylinder to be evaluated under each fatigue alternating load; determining the diameter deformation change amplitude of the to-be-evaluated gas cylinder under each fatigue alternating load; constructing a gas cylinder limit fatigue life curve related to the gas cylinder diameter deformation change amplitude; determining the limit fatigue times of the gas cylinder to be evaluated under each fatigue alternating load; determining a fatigue damage value gamma; and evaluating the fatigue life of the gas cylinder. According to the evaluation method, fatigue life prediction in the gas cylinder design scheme stage can be realized, and meanwhile, the gas cylinder structure optimization design can be guided.

Description

Technical Field

[0001] The present invention relates to the technical field of fatigue life assessment of composite gas cylinders, and in particular to a fatigue life assessment method, system, medium and equipment for aerospace thin-wall seamless lined composite gas cylinders. Background Art

[0002] Thin-walled seamless lined composite gas cylinders are high-pressure gas storage containers suitable for space work. Their main structure includes a seamless lining and a fiber winding layer. This type of gas cylinder is widely used in spacecraft, weapons, satellites and other aircraft due to its simple structure, light weight and high reliability.

[0003] However, due to the thin-walled and lightweight characteristics of aerospace composite gas cylinders, their fatigue life is usually only in the range of hundreds to thousands of times, which belongs to the typical low-cycle fatigue category.

[0004] Nowadays, with the increasing demand for aircraft reuse and long-life applications, the requirements for the fatigue life of gas cylinders are also increasing. In terms of evaluating the fatigue life of gas cylinders, the conventional method is to use the NS curve of the lining material. However, to obtain an accurate NS curve of the lining material, a large amount of test piece data is often required as support. And because there is a significant difference between the force exerted on the test piece during the test and the actual test state of the gas cylinder, it is also necessary to correct the NS curve based on a large amount of gas cylinder fatigue test data.

[0005] In the current model development tasks, we often face the dilemma of lack of basic material data. When faced with higher fatigue life requirements, the conventional practice is to iteratively optimize the structure through cylinder fatigue tests. However, given the strict requirements of aerospace products for light weight, the weight increase allowed after structural optimization is extremely limited, which means that a certain number of test pieces must be tested for fatigue life to determine the product structure. This will inevitably increase the product development cost and development cycle.

[0006] Through searching patent documents, it is found that the patent with publication number CN108918248A discloses a method for calculating the fatigue life reliability of a spacecraft propellant metal diaphragm tank, which includes the following steps: a. establishing a relationship model between the movement of the metal diaphragm in the tank and the amount of propellant output in the tank; b. calculating the fatigue life reliability of the metal diaphragm for a specific volume fluctuation of the propellant in the tank; c. calculating the fatigue life reliability of the metal diaphragm for any volume fluctuation of the propellant in the tank. This patent lacks a comprehensive and detailed evaluation system for the object to be tested.

[0007] In summary, under the current development situation of the aerospace field, it is urgent to propose an economical and efficient fatigue life assessment method for thin-walled seamless lined composite gas cylinders. Summary of the invention

[0008] In view of the defects in the prior art, the purpose of the present invention is to provide a method, system, medium and equipment for fatigue life assessment of thin-walled seamless lined composite gas cylinders for aerospace use.

[0009] According to the present invention, a fatigue life assessment method for aerospace thin-wall seamless lining composite material gas cylinder is provided, comprising the following steps:

[0010] Step S1, obtaining the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and fatigue alternating times of the gas cylinder to be evaluated;

[0011] Step S2, determining the diameter deformation of the gas cylinder to be evaluated under each fatigue alternating load based on the geometric dimensions, winding parameters, material parameters and fatigue alternating pressure;

[0012] Step S3, determining the change amplitude of the diameter deformation of the gas cylinder to be evaluated under each fatigue alternating load based on the diameter deformation;

[0013] Step S4, constructing a gas cylinder limit fatigue life curve related to the change amplitude of the gas cylinder diameter deformation based on the geometric dimensions and the change amplitude;

[0014] Step S5, determining the limit fatigue times of the gas cylinder to be evaluated under each fatigue alternating load based on the limit fatigue life curve and the variation amplitude of the gas cylinder;

[0015] Step S6, determining a fatigue damage value γ based on the limit fatigue times and fatigue alternation times under each fatigue alternation load;

[0016] Step S7, based on the fatigue damage value γ, the fatigue life of the gas cylinder is assessed: if γ≥1, it is assessed that the structure will be fatigue damaged due to the pressure alternating load, and the structure is adjusted to return to step S1; if γ<1, it is assessed that the structure will not be fatigue damaged due to the pressure alternating load.

[0017] Preferably, in step S1, the geometric dimensions include: inner diameter D of the liner, thickness t of the liner base n , Upper head vertex height B s , height of lower head vertex B x , Wall thickness of top head t sf , wall thickness of the lower head vertex t xf 、Nozzle diameter Φ z And process boss diameter Φ t ;

[0018] Winding parameters include: total number of winding layers c, radius of the upper pole hole of each winding layer R s,1 ……R s,c 、Radius R of the lower pole hole of each winding layer x,1……R x,c And the winding thickness of each column segment is x1...x c ;

[0019] Material parameters include: lining material elastic modulus E n 、Poisson's ratio of lining material v n , elastic modulus E of composite materials f1 、E f2 、E f3 and the Poisson's ratio v of the composite material f12 、v f132 、v f23 ;

[0020] The total number of loads i represents the statistical total number of fatigue alternation types;

[0021] Fatigue alternating pressure includes: Maximum pressure P under each load max,1 ...P max,i , minimum pressure P under each load min,1 ...P min,i ;

[0022] The number of fatigue alternations includes: the number of fatigue alternations under each load n1...n i .

[0023] Preferably, step S2 includes the following sub-steps:

[0024] Step S2.1, establishing a finite element mechanical model of the composite gas cylinder based on geometric dimensions, winding parameters and material parameters;

[0025] Step S2.2, setting boundary conditions and applying internal pressure load according to fatigue alternating pressure;

[0026] Step S2.3, the diameter deformation β under the maximum pressure of each load is obtained by finite element simulation calculation max,1 (P max,1 )……β max,i (P max,i ) and the diameter deformation β under the minimum pressure of each load min,1 (P min,1 )……β min,i (P min,i ).

[0027] Preferably, in step S3, the variation amplitude of the diameter deformation under each fatigue alternating load is ε1(β min,1 ,β max,1 )……ε i (β min,i ,β max,i ).

[0028] Preferably, in step S4, the ultimate fatigue life curve of the gas cylinder is obtained from fatigue life test samples accumulated during the development of a large number of models, and the model is continuously optimized through data accumulation.

[0029] Preferably, in step S5, each load limit fatigue number is N1(ε1)...N i (ε i ).

[0030] Preferably, in step S6, the fatigue damage value is γ(n1, N1...n i ,N i ).

[0031] The present invention also provides a fatigue life assessment system for aerospace thin-walled seamless lining composite material gas cylinders, which adopts the above-mentioned fatigue life assessment method for aerospace thin-walled seamless lining composite material gas cylinders, and comprises:

[0032] Module M1: Obtain the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and number of fatigue alternating times of the gas cylinder to be evaluated;

[0033] Module M2: Determine the diameter deformation of the cylinder under each fatigue alternating load based on the geometric dimensions, winding parameters, material parameters and fatigue alternating pressure;

[0034] Module M3: Based on the diameter deformation, determine the change amplitude of the diameter deformation of the gas cylinder to be assessed under each fatigue alternating load;

[0035] Module M4: Based on the geometric dimensions and variation amplitude, the ultimate fatigue life curve of the gas cylinder related to the variation amplitude of the gas cylinder diameter deformation is constructed;

[0036] Module M5: Based on the cylinder limit fatigue life curve and variation amplitude, determine the limit fatigue times of the cylinder to be assessed under each fatigue alternating load;

[0037] Module M6: Determine the fatigue damage value γ based on the limit fatigue number and fatigue alternation number under each fatigue alternation load;

[0038] Module M7: Based on the fatigue damage value γ, the fatigue life of the gas cylinder is assessed: if γ≥1, it is assessed that the structure will be fatigue damaged due to the pressure alternating load, and the structure is adjusted to return to step S1; if γ<1, it is assessed that the structure will not be fatigue damaged due to the pressure alternating load.

[0039] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the fatigue life assessment method for aerospace thin-walled seamless lined composite material gas cylinders.

[0040] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps of the fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinders are implemented.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention can realize fatigue life prediction at the design stage of thin-walled seamless lined composite material gas cylinders, and can also guide the optimization design of gas cylinder structures.

[0043] 2. The construction process of the fatigue failure assessment method of the thin-walled seamless lined composite material gas cylinder of the present invention is simple, convenient and low-cost.

[0044] 3. The fatigue failure assessment method for thin-walled seamless lined composite gas cylinders constructed by the present invention has a wide range of applications and is suitable for fatigue life assessment of all thin-walled seamless lined composite gas cylinders with the same materials and manufacturing processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0046] Figure 1 This is a flow chart of a fatigue life assessment method for aerospace thin-walled seamless liner composite material gas cylinder in an embodiment of the present invention;

[0047] Figure 2 is a structural diagram of a gas cylinder in an embodiment of the present invention;

[0048] Figure 3 is a cloud diagram of radial displacement of a gas cylinder in an embodiment of the present invention;

[0049] Figure 4 is a graph showing the limit fatigue life of a gas cylinder in an embodiment of the present invention;

[0050] Figure 5 This is a diagram for assessing fatigue damage values ​​of a gas cylinder in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0052] The present invention proposes a method, system, medium and equipment for fatigue life assessment of aerospace thin-walled seamless lined composite gas cylinder. The method can accurately predict the fatigue life of the designed gas cylinder at the gas cylinder design stage, and optimize and improve the structure based on the prediction results to achieve the goal of correct design at one time. Moreover, with the continuous accumulation of subsequent test data, the accuracy of the assessment model can be further optimized and improved to better meet the needs of the aerospace field for fatigue life assessment of gas cylinders.

[0053] Embodiment 1:

[0054] Figure 1 The present invention is a flowchart of a fatigue life assessment method for aerospace thin-walled seamless lined composite material gas cylinder in an embodiment of the present invention.

[0055] like Figure 1 As shown, this embodiment provides a fatigue life assessment method for aerospace thin-wall seamless lining composite material gas cylinder, comprising the following steps:

[0056] Step S1, obtaining the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and fatigue alternating times of the gas cylinder to be evaluated.

[0057] In this embodiment, the geometric dimensions include: inner diameter D of the liner, thickness t of the liner base n , Upper head vertex height B s , height of lower head vertex B x , Wall thickness of top head t sf , wall thickness of the lower head vertex t xf 、Nozzle diameter Φ z And process boss diameter Φ t The winding parameters include: the total number of winding layers c, the radius of the pole hole on each winding layer R s,1 ……R s,c 、Radius R of the lower pole hole of each winding layer x,1 ……R x,c And the winding thickness of each column segment is x1...x c . Material parameters include: lining material elastic modulus E n 、Poisson's ratio of lining material v n , elastic modulus E of composite materials f1 、E f2 、E f3 and the Poisson's ratio v of the composite material f12 、v f132 、v f23 The total number of loads i represents the total number of fatigue alternating types. Fatigue alternating pressures include: the maximum pressure P under each load max,1 ...P max,i , minimum pressure P under each load min,1 ...Pmin,i The number of fatigue alternations includes: the number of fatigue alternations under each load n1...n i .

[0058] Step S2, based on the geometric dimensions, winding parameters, material parameters and fatigue alternating pressure, determining the diameter deformation of the gas cylinder to be assessed under each fatigue alternating load.

[0059] Specifically, step S2 includes the following sub-steps:

[0060] Step S2.1, establishing a finite element mechanical model of the composite gas cylinder based on geometric dimensions, winding parameters and material parameters.

[0061] Step S2.2, setting boundary conditions and applying internal pressure load according to fatigue alternating pressure.

[0062] Step S2.3, the diameter deformation β under the maximum pressure of each load is obtained by finite element simulation calculation max,1 (P max,1 )……β max,i (P max,i ) and the diameter deformation β under the minimum pressure of each load min,1 (P min,1 )……β min,i (P min,i ).

[0063] Step S3, based on the diameter deformation, determining the change amplitude of the diameter deformation of the gas cylinder to be evaluated under each fatigue alternating load.

[0064] Specifically, the change amplitude of the diameter deformation under each fatigue alternating load is ε1(β min,1 ,β max,1 )……ε i (β min,i ,β max,i ).

[0065] Step S4, based on the geometric dimensions and the variation amplitude, constructing a gas cylinder limit fatigue life curve related to the variation amplitude of the gas cylinder diameter deformation.

[0066] In this embodiment, the ultimate fatigue life curve of the gas cylinder is obtained from fatigue life test samples accumulated during the development of a large number of models, and the model is continuously optimized through data accumulation.

[0067] Step S5, based on the cylinder limit fatigue life curve and the variation amplitude, determine the limit fatigue times of the cylinder to be evaluated under each fatigue alternating load.

[0068] Specifically, the number of fatigue failures under each load limit is N1(ε1)...N i (ε i ).

[0069] Step S6, determining the fatigue damage value γ based on the limit fatigue times and the fatigue alternation times under each fatigue alternation load.

[0070] Specifically, the fatigue damage value is γ(n1,N1…n i ,N i ).

[0071] Step S7, based on the fatigue damage value γ, the fatigue life of the gas cylinder is assessed: if γ≥1, it is assessed that the structure will be fatigue damaged due to the pressure alternating load, and the structure is adjusted to return to step S1; if γ<1, it is assessed that the structure will not be fatigue damaged due to the pressure alternating load.

[0072] Embodiment 2:

[0073] This embodiment takes an aerospace aluminum alloy thin-walled seamless lining composite material gas cylinder as an example of a gas cylinder to be evaluated, and specifically illustrates the fatigue life evaluation method and results of an aerospace thin-walled seamless lining composite material gas cylinder of the present invention.

[0074] Step S1: obtaining the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and fatigue alternating times of the gas cylinder to be evaluated;

[0075] In this embodiment, the gas cylinder is in the shape of an ellipsoid column, and its specific structure is as follows: Figure 2 The detailed geometrical dimension parameters are shown in Table 1.

[0076] Table 1 Geometrical dimensions of the gas cylinders to be assessed (unit: mm)

[0077]

[0078] The lining material of the gas cylinder to be evaluated is aluminum alloy, and the winding layer material is T1000 carbon fiber composite material. The material parameters are shown in Table 2.

[0079] Table 2 Material parameters

[0080]

[0081] The winding parameters of the gas cylinder to be evaluated are shown in Table 3.

[0082] Table 3 Winding parameters (unit: mm)

[0083] Number of layers Winding direction <![CDATA[Upper pole hole radius R s > <![CDATA[Upper pole hole radius R s,1 > Column winding thickness 1 Circular —— —— 1 2 spiral 30 30 0.46 3 spiral 32 32 0.44 4 spiral 45 45 0.44 5 Circular —— —— 1 6 spiral 56 56 0.44 7 spiral 74 74 0.41 8 spiral 90 90 0.38 9 Circular —— —— 0.5

[0084] The total number of fatigue alternating loads is 2, among which the fatigue alternating pressure of the first load is 0~35MPa~0, and the number of fatigue alternations is 40 times; the fatigue alternating pressure of the second load is 29MPa~40MPa~29MPa, and the number of fatigue alternations is 1000 times.

[0085] Step S2: Based on the geometric dimensions, winding parameters, material parameters and fatigue alternating pressure, determine the diameter deformation of the gas cylinder to be assessed under each fatigue alternating load. The specific steps are as follows:

[0086] Step S2.1: Based on the geometric dimensions, winding parameters and material parameters obtained in step S1, a three-dimensional model is established in ABAQUS finite element software and a mesh is divided;

[0087] Step S2.2: According to the fatigue alternating pressure obtained in step S1, apply the following internal pressure loads according to four working conditions, P max,1 =35MPa, P max,2 =40MPa, P min,2 =29MPa;

[0088] Step S2.3: Obtain the radial displacement distribution cloud diagram of the gas cylinder to be evaluated under various internal pressure loads, such as Figure 3 According to the cloud diagram, the cylinder diameter deformation is determined, and the calculation results of each internal pressure condition are shown in Table 4:

[0089] Table 4 Diameter deformation of the gas cylinder to be assessed (unit: mm)

[0090]

[0091] Step S3: Determine the change amplitude of the diameter deformation of the gas cylinder to be evaluated under each load, ε1 = 3.24 mm,

[0092] ε2=1.08mm;

[0093] Step S4: Combined with the fatigue life test samples accumulated during the development of a large number of models, the cylinder limit fatigue life curve related to the change amplitude ε of the cylinder diameter deformation is established based on the geometric dimensions in step S1, such as Figure 4 As shown;

[0094] Step S5: Determine the limit fatigue times of the gas cylinder to be evaluated under each load through the fatigue life curve, N1=191, N2=1306;

[0095] Step S6: Figure 5 As shown, the fatigue damage value γ of the gas cylinder to be evaluated is determined to be 0.975;

[0096] Step S7: Perform fatigue life assessment of the gas cylinder.

[0097] In this embodiment, the fatigue damage value γ<1, indicating that the structure will not suffer fatigue damage caused by pressure alternating loads.

[0098] Embodiment 3:

[0099] The present embodiment provides a fatigue life assessment system for aerospace thin-walled seamless lined composite gas cylinders. The fatigue life assessment system for aerospace thin-walled seamless lined composite gas cylinders can be implemented by executing the process steps of a fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinders. That is, technical personnel in this field can understand the fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinders as a preferred implementation mode of the fatigue life assessment system for aerospace thin-walled seamless lined composite gas cylinders.

[0100] The system comprises:

[0101] Module M1: Obtain the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and number of fatigue alternating times of the gas cylinder to be evaluated;

[0102] Module M2: Determine the diameter deformation of the cylinder under each fatigue alternating load based on the geometric dimensions, winding parameters, material parameters and fatigue alternating pressure;

[0103] Module M3: Based on the diameter deformation, determine the change amplitude of the diameter deformation of the gas cylinder to be assessed under each fatigue alternating load;

[0104] Module M4: Based on the geometric dimensions and variation amplitude, the ultimate fatigue life curve of the gas cylinder related to the variation amplitude of the gas cylinder diameter deformation is constructed;

[0105] Module M5: Based on the cylinder limit fatigue life curve and variation amplitude, determine the limit fatigue times of the cylinder to be assessed under each fatigue alternating load;

[0106] Module M6: Determine the fatigue damage value γ based on the limit fatigue number and fatigue alternation number under each fatigue alternation load;

[0107] Module M7: Based on the fatigue damage value γ, the fatigue life of the gas cylinder is assessed: if γ≥1, it is assessed that the structure will be fatigue damaged due to the pressure alternating load, and the structure is adjusted to return to step S1; if γ<1, it is assessed that the structure will not be fatigue damaged due to the pressure alternating load.

[0108] Embodiment 4:

[0109] This embodiment provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the steps of the fatigue life assessment method for aerospace thin-walled seamless lined composite material gas cylinders in the above-mentioned embodiment 1 are implemented.

[0110] Embodiment 5:

[0111] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps of the fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinders in the above-mentioned embodiment 1 are implemented.

[0112] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0113] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinder, characterized in that: The steps include: Step S1, obtaining the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and fatigue alternating times of the gas cylinder to be evaluated; Step S2, determining the diameter deformation of the gas cylinder to be evaluated under each fatigue alternating load based on the geometric dimensions, the winding parameters, the material parameters and the fatigue alternating pressure; Step S3, determining the change amplitude of the diameter deformation of the gas cylinder to be evaluated under each fatigue alternating load based on the diameter deformation; Step S4, constructing a gas cylinder limit fatigue life curve related to the change amplitude of the gas cylinder diameter deformation based on the geometric dimensions and the change amplitude; Step S5, determining the limit fatigue times of the gas cylinder to be evaluated under each fatigue alternating load based on the limit fatigue life curve of the gas cylinder and the variation amplitude; Step S6, determining a fatigue damage value γ based on the limit fatigue number and the fatigue alternation number under each fatigue alternation load; Step S7, based on the fatigue damage value γ, the fatigue life of the gas cylinder is assessed: if γ≥1, it is assessed that the structure will be fatigue damaged due to the pressure alternating load, and the structure is adjusted to return to step S1; if γ<1, it is assessed that the structure will not be fatigue damaged due to the pressure alternating load.

2. The fatigue life assessment method of aerospace thin-walled seamless lined composite material gas cylinder according to claim 1 is characterized in that: In step S1, the geometric dimensions include: inner diameter D of the liner, thickness t of the liner base n , Upper head vertex height B s , height of lower head vertex B x , Wall thickness of top head t sf , wall thickness of the lower head vertex t xf 、Nozzle diameter Φ z And process boss diameter Φ t ; The winding parameters include: the total number of winding layers c, the radius of the upper pole hole of each winding layer R s,1 ……R s,c 、Radius R of the lower pole hole of each winding layer x,1 ……R x,c And the winding thickness of each column segment is x1...x c ; The material parameters include: elastic modulus E of the lining material n 、Poisson's ratio of lining material v n , elastic modulus E of composite materials f1 、E f2 、E f3 and the composite material Poisson's ratio v f12 、v f132 、v f23 ; The total number of loads i represents the total number of fatigue alternation types; The fatigue alternating pressure includes: the maximum pressure P under each load max,1 ...P max,i , minimum pressure P under each load min,1 ...P min,i ; The fatigue alternation times include: fatigue alternation times n1...n under each load i .

3. The fatigue life assessment method of aerospace thin-walled seamless lined composite material gas cylinder according to claim 1, characterized in that: The step S2 includes the following sub-steps: Step S2.1, establishing a finite element mechanical model of the composite material gas cylinder based on the geometric dimensions, winding parameters and material parameters; Step S2.2, setting boundary conditions and applying internal pressure load according to the fatigue alternating pressure; Step S2.3, the diameter deformation β under the maximum pressure of each load is obtained by finite element simulation calculation max,1 (P max,1 )……β max,i (P max,i ) and the diameter deformation β under the minimum pressure of each load min,1 (P min,1 )……β min,i (P min,i ).

4. The fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinder according to claim 3 is characterized in that: In step S3, the change amplitude of the diameter deformation under each fatigue alternating load is ε1(β min,1 ,β max,1 )……ε i (β min,i ,β max,i ).

5. The fatigue life assessment method of aerospace thin-walled seamless lined composite material gas cylinder according to claim 4 is characterized in that: In step S4, the limit fatigue life curve of the gas cylinder is obtained from fatigue life test samples accumulated during the development of a large number of models, and the model is continuously optimized through data accumulation.

6. The fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinder according to claim 5 is characterized in that: In step S5, the number of fatigue times for each load limit is N1(ε1)...N i (ε i ).

7. The fatigue life assessment method for aerospace thin-walled seamless lined composite material gas cylinder according to claim 6 is characterized in that: In step S6, the fatigue damage value is γ(n1, N1...n i ,N i ).

8. A fatigue life assessment system for aerospace thin-walled seamless lined composite gas cylinders, characterized in that: A fatigue life assessment method for aerospace thin-walled seamless lined composite gas cylinder according to any one of claims 1 to 7, comprising: Module M1: Obtain the geometric dimensions, winding parameters, material parameters, total load i, fatigue alternating pressure and number of fatigue alternating times of the gas cylinder to be evaluated; Module M2: determining the diameter deformation of the gas cylinder to be assessed under each fatigue alternating load based on the geometric dimensions, the winding parameters, the material parameters and the fatigue alternating pressure; Module M3: determining the change amplitude of the diameter deformation of the gas cylinder to be assessed under each fatigue alternating load based on the diameter deformation; Module M4: constructing a limit fatigue life curve of the gas cylinder related to the change amplitude of the deformation amount of the gas cylinder diameter based on the geometric dimensions and the change amplitude; Module M5: determining the limit fatigue times of the gas cylinder to be assessed under each fatigue alternating load based on the limit fatigue life curve of the gas cylinder and the variation amplitude; Module M6: determining a fatigue damage value γ based on the limit fatigue number and the fatigue alternation number under each fatigue alternation load; Module M7: Based on the fatigue damage value γ, the fatigue life of the gas cylinder is assessed: if γ≥1, it is assessed that the structure will be fatigue damaged due to the pressure alternating load, and the structure is adjusted to return to step S1; if γ<1, it is assessed that the structure will not be fatigue damaged due to the pressure alternating load.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the fatigue life assessment method of aerospace thin-walled seamless lined composite gas cylinder according to any one of claims 1 to 7 are implemented.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the computer program is executed by a processor, the steps of the fatigue life assessment method of aerospace thin-walled seamless lined composite gas cylinder according to any one of claims 1 to 7 are implemented.

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