A method for predicting fatigue life of space docking lock system by accelerating stress decay

Abstract

The present invention provides a method for predicting the fatigue life of a space docking latch system by accelerating stress attenuation, belonging to the technical field of stress measurement. An accelerated degradation test is carried out on the docking latch system to obtain the measurement time under each temperature stress T n , t ni , t n and the corresponding degradation amount y ni and y n . Then, the pseudo-life and median logarithmic life of the docking latch system at each temperature under different initial stresses are calculated, and the fatigue life of the docking latch system at the engineering temperature is obtained by fitting. Through the solution of the present invention, it is possible to accurately predict the service life of the docking latch system under space conditions on the basis of ground tests.

Description

Technical Field

[0001] The present invention relates to the field of stress measurement, including the measurement of tension and stress attenuation of mechanical structures in accelerated degradation tests, and specifically to predicting the fatigue life of a docking lock system of aerospace equipment by measuring the tension degradation rate of a space docking lock system through an accelerated degradation test. Background Art

[0002] The application prospects of space science research are very broad. The construction of a long-term Chinese space station can provide an advanced scientific research platform for cutting-edge research in many fields in my country. Aerospace products used in space science research are high-reliability products. With the continuous improvement and improvement of design, manufacturing methods and materials used, their reliability is getting higher and higher. The degradation process of products in the working environment is very slow. Therefore, the conventional stress measurement method is adopted. In a very long measurement cycle, the change in the amount of product degradation is negligible. However, for the space docking lock system, its docking reliability, accuracy and service life requirements are very high. In the prior art, the service life of mechanical structures is usually judged by experience. For batch products, the service life can also be predicted by the limit test method. However, the docking lock system of the space station has high cost, small quantity, and extremely high reliability requirements. It is obviously not suitable for the limit test method to predict its service life. CN112926144A discloses a multi-stress accelerated life test coupling effect analysis and life prediction method. This method is mainly a theoretical study on the coupling effect and life prediction of general mechanical mechanisms. The process is very complicated and has no practical guiding significance for the fatigue life prediction of the space station docking lock system. Summary of the invention

[0003] The present invention achieves the purpose of the invention through a reasonable combination of the following technical solutions or technical features.

[0004] The present invention proposes a method for predicting fatigue life of a space docking lock system by accelerating stress decay, comprising the following steps:

[0005] Step S100: setting the initial tension of the docking lock system for the temperature stress step loading test and multiple continuous test temperatures of step-up, the initial test temperature is greater than room temperature, the test time at each test temperature is greater than 100 hours, multiple groups of accelerated degradation tests are performed, each group has a different initial tension, the initial tension values ​​are 34kN, 31.7kN, 30kN, 33kN respectively, and 10kN is set as the tension degradation failure value.

[0006] Step S200: Perform a temperature stress step loading test, starting from the initial test temperature, the docking lock system is loaded with a rated load to reach the initial tension value, and the temperature is raised to the next test temperature after each test temperature test is completed, and the test is continued until the tension degradation amount reaches the tension degradation failure value. The test is completed, and different temperature stresses are recorded asT n , at this temperature stress T n Load next i The time point of measuring the tension degradation is recorded as t ni , at this temperature stress T n The last time the tension degradation was measured under loading was recorded as t n At this temperature stress T n Next load i The tension degradation obtained by the measurement is recorded as y ni , at this temperature stress T n The tension degradation of the last test under loading is recorded as y n .

[0007] Step S300: Draw according to the data recorded in step S200 y ni -t ni The relationship diagram is shown in Figure 2, and the intercept c and slope d of the fitting line are obtained by fitting, and a linear model of tension performance degradation with an embedded first rule is constructed.

[0008] Step S400: Based on the tension performance degradation linear model constructed in step S300, a pseudo life module at different test temperatures with the second rule embedded therein is constructed.

[0009] Step S500: input the data recorded in step S200 into the pseudo life module at different test temperatures to obtain the pseudo life of each group of docking locks at different test temperatures.

[0010] Step S600: Based on the normal distribution, obtain the temperature stress of the docking lock system T n The median logarithmic pseudolifetime under m n .

[0011] Step S700: Fitting m n With 1 / T n The linear relationship between them is obtained, and the slope a and intercept b of the fitting line are obtained.

[0012] Step S800: inputting the slope a and the intercept b obtained in step S700 into a preset fatigue life prediction module for a docking lock system with a third rule embedded therein, to obtain the fatigue life of the docking lock system at an engineering temperature.

[0013] Preferably, in step S100, the test temperatures are 75°C, 85°C, 95°C, 105°C, and 115°C, respectively, and four groups of tests are performed, and the initial tensions corresponding to each group are 34 kN, 31.7 kN, 30 kN, and 33 kN, respectively.

[0014] Preferably, in step S300, the first rule is:

[0015] ;

[0016] in, y ( t ) is the tension degradation amount, t is the degradation time, c is the intercept of the fitted line, d is the slope of the fitted line obtained by fitting.

[0017] Preferably, in step S400, the second rule is:

[0018] ;

[0019] in, t n伪寿命 is the pseudo-lifetime calculated by the degradation linear model, y 阈值 To specify the failure threshold, y n-1 The temperature stress T n-1 The last measured tension degradation, S n-1 To reduce the temperature stress T n The initial degradation time t n-1 By converting the same degradation amount into T n The time required for degradation is c n Temperature stress T n The intercept of the degenerate linear model obtained by fitting below is d n Temperature stress T n The slope of the degenerate linear model obtained by fitting below.

[0020] Preferably, S n-1 Obtained through the following methods,

[0021] ;

[0022] in, d n-1 Temperature stress T n-1 The slope of the degenerate linear model obtained by fitting is t n-1 and t n-2 Temperature stress T n-1 and temperature stress T n-2 The last time the tension degradation was measured under loading, S n-2 To reduce the temperature stress T n-1 The initial degradation time t n-2 By converting the same degradation amount into T n-1 The time required for degradation is t 0 and S 0 is the initial time.

[0023] Preferably, step S600 includes:

[0024] Step S610: Fasten different sets of docking locks together T n Sort the pseudo-lifetimes in ascending order and take the logarithm to obtain k t n伪寿命 , k Indicates the pseudo life of a specimen in ascending order. k individual data;

[0025] Step S620: docking the lock system under temperature stress T n The median logarithmic pseudolifetime under m n It is obtained as follows;

[0026] ;

[0027] ;

[0028] Among them, σ n Temperature stress T n The standard deviation of the logarithmic pseudolifetime under m n Temperature stress T n The median logarithmic pseudo-lifetime under l is the number of test groups, k t n伪寿命The temperature stress T n The following groups of specimens are sorted by logarithmic pseudo lifespan. k The logarithmic pseudo-lifetime, k d is the probability found through the standard normal function table P ( t < k t n伪寿命 ) corresponding to the value.

[0029] Preferably, in step S800, the third rule is: ,in, a is the slope of the fitting line obtained in step S700, b is the intercept of the fitting line obtained in step S700, T is the engineering temperature corresponding to the actual working condition, m is the project temperature T The average pseudo life calculated under the above conditions is the fatigue life of the docking lock system at the engineering temperature.

[0030] The present invention also proposes a system for predicting fatigue life of a space docking lock system by accelerating stress decay, comprising:

[0031] A data storage device for storing the initial tension, test temperature, test duration, test measurement time points and tension degradation amount obtained from the temperature stress step loading test of the docking lock system; a docking lock system fatigue life prediction device, the docking lock system fatigue life prediction device comprising a processor for implementing the aforementioned method.

[0032] The present invention also provides a computer-readable storage medium on which a computer program is stored. The computer program stored in the storage medium is used to be executed to implement the above method.

[0033] The beneficial effects of the present invention are as follows:

[0034] An accelerated performance degradation test of the docking lock is carried out under temperature stress higher than normal operating conditions. A linear degradation model of the docking lock performance is established based on the test data. The service life under normal stress is estimated through a pre-set failure threshold, avoiding product damage that is easily caused by extreme testing. The test cycle is shortened, the test cost is reduced, and the prediction results are accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the relationship between time and temperature for an embodiment of a temperature stress step loading test.

[0036] Figure 2 for d -lnt n伪寿命 Relationship diagram.

[0037] Figure 3 is the median logarithmic pseudo lifespan m n The inverse of the temperature stress 1 / T n relationship diagram. DETAILED DESCRIPTION

[0038] The present invention will be described below based on examples, but the present invention is not limited only to these examples.

[0039] It should be understood that the terms "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] It should be noted that the use of step numbers to refer to certain specific method steps in the present invention is only for the purpose of convenience and simplicity of description, and is by no means intended to limit the order of these method steps by letters or numbers. Those skilled in the art will understand that the order of the relevant method steps should be determined by the technology itself and should not be inappropriately limited by the existence of step numbers. Those skilled in the art can determine various permissible and reasonable step orders based on the technology itself.

[0041] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are only used to introduce the present invention in detail and are not intended to limit the present invention. It should also be noted that since the technical scheme of the present invention has been clearly described in the content of the invention, the overall scheme is no longer described in detail in the specific embodiments, and only a part of the specific experimental process is described to illustrate the implementation process of the technical scheme of the present invention.

[0042] The room temperature in the present invention is 25° C. or 298 K. The engineering temperature is the equivalent temperature when the device is actually working, and the engineering temperature in the embodiment of the present invention is equal to the room temperature.

[0043] The embodiment of the scheme includes the following steps:

[0044] Step S100: setting the initial tension of the temperature stress step loading test on the docking lock system and multiple continuous test temperatures of step-up, the initial test temperature is greater than room temperature, the test time at each test temperature is greater than 100 hours, the accelerated degradation test is performed in multiple groups, each group has a different initial tension, and 10kN is set as the tension degradation failure value.

[0045] Specifically, the accelerated performance degradation test of the docking lock system is a test technology and method that uses the performance degradation data of the product at high stress levels or accelerated stress levels to extrapolate and predict the life characteristics at normal stress levels by finding the relationship between product life and stress, such as an accelerated model, on the basis of the unchanged failure mechanism. The stresses in this test mainly include tension and temperature. The test is divided into four groups according to the loading time of different temperature stresses and different initial tensions. The initial tension of the first group is 34kN, the initial tension of the second group is 31.7kN, the initial tension of the third group is 30kN, and the initial tension of the fourth group is 33kN. The initial tension is achieved by loading the docking lock system with a rated load. The test temperatures are: 75℃, 85℃, 95℃, 105℃, and 115℃ respectively.

[0046] Step S200: Perform a temperature stress step loading test, starting from the initial test temperature, the docking lock system is loaded with a rated load to reach the initial tension. After each test temperature test, the temperature is raised to the next test temperature and the test is continued until the measured tension degradation reaches the failure value of 10kN. The test is terminated. Figure 1 shown.

[0047] Specifically, the step loading method is adopted, and the temperature is monitored in the temperature control box of the experimental equipment. The tension degradation parameters and the corresponding time in each temperature stress loading time are obtained. The collected data are now symbolized as follows: Different temperature stresses are recorded as T n , at this temperature stress T n Load next i The time point of measuring the tension degradation is recorded as t ni , at this temperature stress T n The last time the tension degradation was measured under loading was recorded as t n At this temperature stress T n Load the next i The tension degradation obtained by the measurement is recorded as y ni , at this temperature stress T n The tension degradation of the last test under loading is recorded as y n .

[0048] In one embodiment of the present invention, the temperature stress and the corresponding loading time of the accelerated performance degradation test are given in Table 1.

[0049] Table 1: Step loading test temperature-timetable

[0050]

[0051] During the test, the tension degradation is measured every 5 hours, and the corresponding temperature stress is recorded during the measurement process. T n The measurement time point t = t ni (in hours), and the tension degradation of the docking lock system y = y ni The measurement time points at 0 hours, 10 hours, and 20 hours from the start of the test are recorded as the original group of each group, and the measurement time points at 5 hours, 15 hours, and 25 hours from the start of the test are recorded as the expanded group of each group of tests. In this way, the temperature stress of each test T n There can be eight groups of control experiments. Table 2 shows some of the experimental results of the first group of experiments in this example.

[0052] Table 2: Partial test results of the first group of accelerated degradation tests

[0053]

[0054] Step S300: Draw according to the data recorded in step S200 y ni - t ni The relationship diagram is shown in Figure 2, and the intercept c and slope d of the fitting line are obtained by fitting, and a linear model of tension performance degradation with an embedded first rule is constructed.

[0055] Specifically, the process of constructing the tension performance degradation linear model is as follows:

[0056] When the temperature stress of the environment is taken as the temperature equivalent, the relationship between the reaction rate and temperature of the test product conforms to the following relationship:

[0057] (1);

[0058] in, M is the product characteristic value or degradation amount, t is the degradation time, dM / dt is the reaction rate, A is a constant, E is the activation energy, k B is the Boltzmann constant, T is the test temperature (thermodynamic temperature T=℃+273.15).

[0059] Integrating the above formula yields:

[0060] (2) ;

[0061] Taking the logarithm of the above formula, we get:

[0062] (3);

[0063] Right now:

[0064] (4);

[0065] in, , The above formula is usually called the acceleration model or acceleration equation. a、b is a constant determined by the experiment, the degradation time t The logarithm of product life and test temperature stress T is proportional to the reciprocal of .

[0066] The rate of change of the degradation amount of the degradation linear model (called the degradation rate) is a constant, that is:

[0067] (5);

[0068] in, y ( t ) is the tension degradation amount, t is the degradation time, c is the intercept of the fitted line, d is the slope of the fitted line, that is, c , d are the intercept and slope of the degradation linear model, respectively.

[0069] The first rule in the degenerate linear model is formula (5).

[0070] Step S400: Based on the tension performance degradation linear model constructed in step S300, a pseudo life module at different test temperatures with the second rule embedded therein is constructed.

[0071] After obtaining the data of the tension degradation amount and the measurement time point corresponding to the step loading test, i.e. the accelerated degradation test, under different temperature stresses, a pseudo-life module with the second rule embedded at different test temperatures can be constructed. This module calculates the failure threshold at the specified failure threshold through the tension performance degradation linear model. y 阈值 The specimen is under temperature stress T n Pseudo-lifetime t n伪寿命 .

[0072] The calculation process is as follows,

[0073] In step S300, a linear model of tension performance degradation is established, and the tension degradation amount y ( t ) and degradation time t The relationship is,

[0074] y ( t )= c + dt (6);

[0075] In formula (6), CD are the intercept and slope in equation (5) respectively.

[0076] Through the linear relationship, the time to reach the specified failure threshold at different temperatures can be simply calculated, that is, the pseudo life.

[0077] (7);

[0078] In formula (7), t 伪寿命 is the pseudo life under single temperature stress calculated by the degradation linear model, y 阈值 is the specified failure threshold, CD are the intercept and slope in equation (5) respectively.

[0079] Since the specimen was subjected to degradation test under step loading, the temperature stress T n ( n >1) at the start time, has been T 1 - T n-1 The degradation process, at which the temperature stress T n The initial tension value under the test is not 34kN at the beginning of the test, so the temperature stress needs to be T n The initial degradation time t n-1 (i.e. the previous temperature stress T n-1 The last time the tension degradation was measured under load) was converted to the full load by the same degradation. T n The time required for degradation S n-1 Then, the pseudo-life relationship is obtained by fitting the tension degradation amount obtained in the stress time period with the time, which is expressed as:

[0080] (8);

[0081] in, t n伪寿命 is the pseudo-lifetime calculated by the degradation linear model, y 阈值 To specify the failure threshold, y n-1 The temperature stress T n-1 The last measured tension degradation, S n-1 To reduce the temperature stress T n The initial degradation time t n-1 By converting the same degradation amount into T n The time required for degradation is c n Temperature stress T n The intercept of the degenerate linear model obtained by fitting below is d n Temperature stress T n The slope of the degraded linear model obtained by fitting. d n and c n Through y ni - t ni The relationship diagram is obtained by fitting using the least squares method. The relationship diagram needs to be based on the measurement time of the accelerated degradation test. t ni The horizontal axis is the measured tension degradation amount y ni Is the vertical axis.

[0082] The second rule in the pseudo life module at different test temperatures is formula (8).

[0083] Step S500: input the data recorded in step S200 into the pseudo life module at different test temperatures to obtain the pseudo life of each group of docking locks at different test temperatures.

[0084] The fitting graph is drawn for part of the data of the first group of tests under five temperature stresses given in Table 2, and the following formula is used to calculate:

[0085] (9);

[0086] (10);

[0087] (11);

[0088] In the formula, m n Indicates the temperature T n The number of times the tension degradation is measured is d n-1 Temperature stress T n-1 The slope of the degenerate linear model obtained by fitting below is t n-1 and t n-2 Temperature stress T n-1 and temperature stress T n-2 The last time the tension degradation was measured under loading, S n-2 To reduce the temperature stress T n-1 The initial degradation time t n-2 By converting the same degradation amount into T n-1 The time required for degradation is t 0 and S 0 is the initial time.

[0089] Substituting the data in Table 2 into equations (8) to (11), the pseudo life of the first group of docking locks at each test temperature can be calculated. Similarly, substituting the data of other groups into equations (8) to (11), the corresponding pseudo life of each group at different temperatures can be obtained. Tables 3 and 4 give the pseudo life calculation results of each group of tests.

[0090] Table 3: Pseudo-lifetime calculation results for groups 1-4

[0091]

[0092] Table 4: Pseudo-lifetime calculation results of 1-4 expansion group

[0093]

[0094] Step S600: Based on the normal distribution, obtain the temperature stress of the docking lock system T n The median logarithmic pseudolifetime under m n .

[0095] Firstly, the relationship between the pseudo-lifetime distribution of the docking-locking system and the temperature stress is constructed.

[0096] In step S500, the stress of different groups of docking locks at different temperatures can be calculated. T n For the same temperature T n , the distribution of pseudo-life of multiple different specimens is assumed to be log-normal distribution. T n Sort the pseudo-lifetimes in ascending order and take the logarithm to obtain k t n伪寿命 , where the superscript k Indicates the pseudo life of a specimen in ascending order. k The corresponding statistical probability value can be obtained by querying the median rank query table P ( t < k t n伪寿命 ), denoted as k P n , the median rank query table of 8 groups of test data is given in Table 5.

[0097] Table 5: Median rank sorting probability correspondence table

[0098]

[0099] At the same temperature stress T n Under this condition, the pseudo-life distribution of the specimen obeys the lognormal distribution, and the lognormal distribution function F ( t ) is expressed as,

[0100] (12);

[0101] in f (·) is the standard normal probability function, t is the life of the specimen, m is the mean of the logarithmic pseudo-lifetime, that is, the median logarithmic pseudo-lifetime, s is the standard deviation of the normal distribution of the logarithmic pseudolifetime.

[0102] If the order ,So d and t The relationship can be expressed as,

[0103] (13);

[0104] in k d is the probability found through the standard normal function table P (t < k t n伪寿命 ) corresponding to the value, m n Represents temperature stress T n The mean of the logarithmic pseudo-lifetime under σ, that is, the median logarithmic pseudo-lifetime, σ n Represents temperature stress T n The standard deviation of the normal distribution of the logarithmic pseudo-lifetime under . Observing this formula, we can find that d With ln t n伪寿命 If there is a linear relationship between d -ln t n伪寿命 Relationship diagram, such as Figure 2 As shown, the horizontal axis is the logarithmic pseudo lifespan ln t n伪寿命 , the vertical axis is the probability of the standard normal distribution d , then the stress at different temperatures can be obtained by fitting T n The corresponding mean pseudo-lifetime, i.e. median logarithmic pseudo-lifetime, is calculated as:

[0105] (14);

[0106] (15);

[0107] In the formula, σ n Temperature stress T n The standard deviation of the normal distribution of the logarithmic pseudo-lifetime under , m n Temperature stress T n The mean of the logarithmic pseudo-lifetime under , that is, the median logarithmic pseudo-lifetime, l is the number of test groups, k t n伪寿命 The temperature stress T n The following groups of specimens are sorted in ascending order of logarithmic pseudo lifespan. k The logarithmic pseudo-lifetime, k d is the probability found through the standard normal function table P ( t < k t n伪寿命 ) corresponding to the value.

[0108] Step S700: Fitting mn With 1 / T n The linear relationship between them is obtained, and the slope a and intercept b of the fitting line are obtained.

[0109] In step S300, the linear model of the docking lock system degradation is established. It can be seen that for the same degradation amount Δy, the logarithm of the degradation time ln t The inverse of the temperature stress 1 / T The linear relationship is obtained by calculating in step S600 at different temperatures T 1 , T 2 , T 3 , T 4 The median logarithmic pseudolifetime under m n , then we can fit m n With 1 / T n The linear relationship between the median logarithmic pseudo lifespan m n The vertical axis is the inverse of the temperature stress 1 / T n As the horizontal axis, draw a scatter plot and fit the corresponding straight line to obtain the median logarithmic pseudo lifespan m n The inverse of the temperature stress 1 / T n The relationship diagram, such as Figure 3 shown.

[0110] On this basis, the slope a and intercept b can be fitted, and the calculation formula is:

[0111] (16);

[0112] (17);

[0113] In formula (16) and formula (17), N Temperature stress T n The number of groups of experiments conducted under m n is the temperature stress T n The median log pseudo-lifetime was calculated below.

[0114] Step S800: inputting the slope a and the intercept b obtained in step S700 into a preset fatigue life prediction module for a docking lock system with a third rule embedded therein, to obtain the fatigue life of the docking lock system at an engineering temperature.

[0115] The median logarithmic pseudo-lifetime at engineering temperature, the third rule is:

[0116] (18);

[0117] In the formula, a is the slope obtained by fitting in step S700, b is the intercept obtained by fitting in step S700, T is the engineering temperature corresponding to the actual working condition, m is the project temperature T The average pseudo life calculated below is the fatigue life of the docking lock at engineering temperature.

[0118] The project temperature T =298K is substituted into formula (18), and the service life of the docking lock system is obtained to be 51.19 years.

[0119] Based on the above method, a system for predicting the fatigue life of a space docking lock system by accelerating stress decay can be established. The system includes a data storage device for storing the initial tension, test temperature, test duration, test measurement time point, and tension degradation amount obtained by the test of the temperature stress step loading test of the docking lock system. The system also includes a docking lock system fatigue life prediction device, and the docking lock system fatigue life prediction device includes a processor for implementing the above method.

[0120] Based on the above method and system, a computer-readable storage medium can be constructed, on which a computer program is stored. The computer program stored in the storage medium is used to be executed to implement the above method.

[0121] Those skilled in the art will appreciate that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

Claims

1. A method for predicting fatigue life of space docking lock system by accelerating stress decay, characterized in that: The following steps are involved: Step S100: setting the initial tension of the docking lock system for the temperature stress step loading test and the continuous multiple test temperatures of the step-up, the initial test temperature is greater than the room temperature, the test time at each test temperature is greater than 100 hours, multiple groups of accelerated degradation tests are performed, each group has a different initial tension value, the initial tension values ​​are 34kN, 31.7kN, 30kN, 33kN respectively, and 10kN is set as the tension degradation failure value; Step S200: Perform a temperature stress step loading test, starting from the initial test temperature, the docking lock system is loaded with a rated load to reach the initial tension, and the temperature is raised to the next test temperature after each test temperature test is completed, and the test is continued until the tension degradation amount reaches the tension degradation failure value. The test is completed, and different temperature stresses are recorded as T n , at this temperature stress T n Load next i The time point of measuring the tension degradation is recorded as t ni , at this temperature stress T n The last time the tension degradation was measured under loading was recorded as t n At this temperature stress T n Load the next i The tension degradation obtained by the measurement is recorded as y ni , at this temperature stress T n The tension degradation of the last test under loading is recorded as y n ; Step S300: Draw according to the data recorded in step S200 y ni - t ni Relationship diagram, the intercept c and slope d of the fitting line are obtained by fitting, and a linear model of tension performance degradation with the first rule embedded is constructed; Step S400: Based on the tension performance degradation linear model constructed in step S300, a pseudo life module at different test temperatures with the second rule embedded therein is constructed. Step S500: inputting the data recorded in step S200 into a pseudo life module at different test temperatures to obtain the pseudo life corresponding to each group of docking locks at different test temperatures; Step S600: Based on the normal distribution, obtain the temperature stress of the docking lock system T n The median logarithmic pseudolifetime under μ n ; Step S700: Fitting μ n With 1 / T n The linear relationship between them is used to obtain the slope a and intercept b of the fitting line; Step S800: inputting the slope a and the intercept b obtained in step S700 into a preset fatigue life prediction module for a docking lock system with a third rule embedded therein, to obtain the fatigue life of the docking lock system at an engineering temperature; In step S400, the second rule is: ； in, t n伪寿命 is the pseudo-lifetime calculated by the degradation linear model, y 阈值 To specify the failure threshold, y n-1 The temperature stress T n-1 The last measured tension degradation, S n-1 To reduce the temperature stress T n The initial degradation time t n-1 By converting the same degradation amount into T n The time required for degradation is c n Temperature stress T n The intercept of the degenerate linear model obtained by fitting below is d n Temperature stress T n The slope of the degenerate linear model obtained by fitting below.

2. The method for predicting fatigue life of space docking lock system by accelerating stress decay according to claim 1, characterized in that: In step S100, the test temperatures are 75°C, 85°C, 95°C, 105°C, and 115°C, respectively. Four groups of tests are performed, and the initial tensions corresponding to each group are 34 kN, 31.7 kN, 30 kN, and 33 kN, respectively.

3. The method for predicting fatigue life of space docking lock system by accelerating stress decay according to claim 1, characterized in that: In step S300, the first rule is: ； in, y (t) is the tension degradation amount, t is the degradation time, c is the intercept of the fitted line, d is the slope of the fitted line obtained by fitting.

4. The method for predicting fatigue life of space docking lock system by accelerating stress decay according to claim 1, characterized in that: S n-1 Obtained through the following methods, ； in, t 0= S 0=0, d n-1 Temperature stress T n-1 The slope of the degenerate linear model obtained by fitting is t n-1 and t n-2 Temperature stress T n-1 and temperature stress T n-2 The last time the tension degradation was measured under loading, S n-2 To reduce the temperature stress T n-1 The initial degradation time t n-2 By converting the same degradation amount into T n-1 The time required for degradation is t 0 and S 0 is the initial time.

5. The method for predicting fatigue life of space docking lock system by accelerating stress decay according to claim 1, characterized in that: Step S600 includes: Step S610: Fasten different sets of docking locks together T n Sort the pseudo-lifetimes in ascending order and take the logarithm to obtain k t n伪寿命 , k Indicates the pseudo life of a specimen in ascending order. k individual data; Step S620: docking the lock system under temperature stress T n The median logarithmic pseudolifetime under μ n It is obtained as follows; ； ； Among them, σ n Temperature stress T n The standard deviation of the logarithmic pseudolifetime under μ n Temperature stress T n The median logarithmic pseudo-lifetime under l is the number of test groups, k t n伪寿命 The temperature stress T n The following groups of specimens are sorted by logarithmic pseudo lifespan. k The logarithmic pseudo-lifetime, k δ is the probability found through the standard normal function table P ( t < k t n伪寿命 ) corresponding to the value.

6. The method for predicting fatigue life of space docking lock system by accelerating stress decay according to claim 1, characterized in that: In step S800, the third rule is: , in, a is the slope of the fitting line obtained in step S700, b is the intercept of the fitting line obtained in step S700, T is the engineering temperature corresponding to the actual working condition, μ is the engineering temperature T The average pseudo life calculated below is the fatigue life of the docking lock system at engineering temperature.

7. A system for predicting fatigue life of space docking lock system by accelerating stress decay, characterized in that: include: A data storage device, used to store the initial tension, test temperature, test duration, test measurement time point and tension degradation amount obtained from the temperature stress step loading test of the docking lock system; A device for predicting fatigue life of a docking lock system, wherein the device comprises a processor for implementing the method according to any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program stored in the storage medium is used to be executed to implement the method according to any one of claims 1 to 6.

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