Method and device for determining tension attenuation of butt-joint locking system under expected life

Abstract

The invention provides a method and device for determining tension attenuation of a docking lock system under expected life, and the method comprises the steps: building a prediction model of the service life of the space docking lock system through the analysis and simplification of a force transmission path of the space docking lock system, the determination and conservative analysis of small-deformation parts of the space docking lock system, and the tension attenuation assumption; and parameters in the model are determined by using methods such as linear fitting and the like by measuring the force deformation amount of each tension attenuation deformation body in the space butt joint locking system at different time points, so that tension attenuation data required by the service life of the space butt joint locking system are analyzed. By means of the method and device, whether the service life of the space butt joint locking system can meet the expected service life or not during tension attenuation under the space working condition can be accurately judged on the basis of a ground test.

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 under expected service life, and specifically to measuring the force attenuation of main deformation components of a space docking lock system of aerospace equipment at different temperatures and time points, thereby determining the tension attenuation under actual working conditions and expected service life of the space docking lock system. Background Art

[0002] Space rendezvous and docking technology is a core technology that must be mastered in manned space activities. The space docking mechanism is the core device for performing space docking missions. Its research involves theories and technologies in many aspects, such as mechanism design, structural analysis, dynamics and control. The space docking lock system is an important component of the mechanical components of the docking mechanism and an important component that connects adjacent compartments of the space station. Its life plays a vital role in the safety of the space station. Therefore, the service life of the space docking lock system is of great significance to the overall life of the space station. The research and testing of the life of the space docking lock system is an important part of ensuring the safe and stable operation of the space station, because the space docking lock system is equipped with docking hooks, including active hooks and passive hooks. After the tension attenuation between the hooks reaches the safety threshold, the two cannot guarantee the stiffness and sealing of the docking mechanism connection, and may even cause the lock to fail, endangering the safety of the space station. In the prior art, the service life of the mechanical structure is usually judged by experience, and for batch products, the service life can also be predicted by extreme testing. For example, CN112926144A discloses a multi-stress accelerated life test coupling effect analysis and life prediction method. This method is mainly a theoretical study of the coupling effect and life prediction of general mechanical mechanisms. The process is very complicated and has no practical guiding significance for the stress attenuation analysis of space docking lock systems. 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 provides a method for determining the attenuation of tension of a docking lock system under expected service life, comprising the following steps: Step S100: The active lock hook, the passive lock hook, the disc spring, the eccentric sleeve and the housing in the space docking lock system are set as tension attenuation deformation bodies. Based on the force relationship between the deformation bodies after the space docking lock system is docked, a space docking lock system tension attenuation simplified module embedded with the first rule is constructed. The space docking lock system tension attenuation simplified module and the lock hook have an equivalent stiffness K 锁钩 , Equivalent stiffness K of eccentric sleeve 偏心套 , Force attenuation △FR caused by stress relaxation of disc spring 碟簧 , Equivalent stiffness K of disc spring 碟簧 , Force attenuation due to stress relaxation of the lock hook △FR锁钩 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve 偏心套 And the deformation of the shell △L 壳体 Related; Step S200: setting the initial tension P, expected life and N different test temperatures for the tension decay test of the space docking lock system, wherein the N test temperatures are all greater than room temperature, N≥2, and continuously loading a certified load for a certain period of time at each test temperature, and measuring the tension decay amount ΔP of each tension decay deformation body at a time point t after a predetermined period of time at each test temperature, wherein the certified load is a load that maintains the initial tension P; Step S300: According to the time point t at N different test temperatures obtained in step S200 and the tension attenuation at the time point, the attenuation rate B at the engineering temperature and the 1-hour attenuation rate A at the engineering temperature are obtained through curve fitting and linear fitting; Step S400: According to the attenuation rate B at the engineering temperature and the 1-hour attenuation rate A at the engineering temperature obtained in step S300, a tension attenuation value module for the expected working life of the tension attenuation deformation body at the engineering temperature is constructed with the second rule embedded therein; Step S500: Input the expected life into the tension attenuation value modules of the disc spring, eccentric sleeve, and lock hook constructed in step S400 to obtain the force attenuation ΔFR caused by the stress relaxation of the disc spring. 碟簧 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve 偏心套 , Force attenuation due to stress relaxation of the lock hook △FR 锁钩 ; Step S600: Obtain the equivalent stiffness K of the disc spring according to the rated load, the static stiffness of the disc spring, the eccentric sleeve, and the lock hook at the engineering temperature, and the initial tension deformation under the rated load. 碟簧 , Equivalent stiffness K of eccentric sleeve 偏心套 , equivalent stiffness K of the lock hook 锁 hook; Step S700: Obtain the deformation ΔL of the shell according to the Young's modulus of the shell material and the initial tension P 壳体 ; Step S800: Input the values ​​obtained in steps S500-S700 into the simplified module of tension attenuation of the space docking lock system constructed in step S100 to obtain the tension attenuation of the space docking lock system under the expected lifespan.

[0005] Preferably, the first rule in step S100 is: Among them, △F 单套对接锁 is the tension attenuation of the space docking lock system, K 锁钩 is the equivalent stiffness of the lock hook, K偏心套 is the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K is the force attenuation caused by the stress relaxation of the disc spring. 碟簧 is the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by stress relaxation of the lock hook. 偏心套 is the force attenuation caused by the stress relaxation of the eccentric sleeve, △L 壳体 is the deformation of the shell.

[0006] Preferably, the initial tension in S200 is 37 kN, the expected life is 15 years, the N different temperatures are 85°C, 115°C, 145°C and 175°C, and the tension attenuation of each tension attenuation deformable body is measured and recorded every 5 hours at each temperature.

[0007] Preferably, step S300 includes: Step S310: according to the measurement time points t and the tension attenuation ΔP at N different test temperatures, a tension attenuation-time logarithmic relationship curve is drawn, and in combination with the linear relationship between the tension attenuation and the time logarithm, a slope is fitted using the least square method, and the slope is the attenuation rate Vsn at the test temperature; Step S320: plotting the decay rate-temperature reciprocal relationship curve at different test temperatures, and fitting the slope of the decay rate and the temperature reciprocal in combination with the linear relationship between the decay rate and the temperature reciprocal, wherein the slope of the decay rate and the temperature reciprocal is the average decay rate; Step S330: a curve of the logarithm of the average decay rate and the inverse of the temperature is drawn according to the average decay rate, and the linear relationship between the logarithm of the average decay rate and the inverse of the temperature is fitted using the least squares method to obtain the decay rate B at the engineering temperature. Step S340: draw a curve of the relationship between the logarithm of the 1-hour decay rate and the inverse of the temperature, and combine the linear relationship between the logarithm of the 1-hour decay rate and the inverse of the temperature to obtain the intercept of the 1-hour decay rate A at the engineering temperature.

[0008] Preferably, the second rule embedded in step S400 is: △P=A+Blnt,B=V s ; Where ΔP is the tension attenuation, A is the 1-hour attenuation rate at engineering temperature, B is the attenuation rate at engineering temperature, t is time, V s is the stress relaxation rate at engineering temperature.

[0009] Preferably, the obtained tension attenuation of the space docking lock system under the expected lifespan is compared with a preset tension attenuation threshold, and if the obtained tension attenuation of the space docking lock system under the expected lifespan is not higher than the preset tension attenuation threshold, the output is qualified.

[0010] The present invention also provides a device for determining the attenuation of tension of a docking lock system under expected service life, the device comprising: A simplified module for space docking lock system tension attenuation, in which the first rule is embedded, and the simplified module for space docking lock system tension attenuation and the equivalent stiffness K of the lock hook 锁钩 , Equivalent stiffness K of eccentric sleeve 偏心套 , Force attenuation △FR caused by stress relaxation of disc spring 碟簧 , Equivalent stiffness K of disc spring 碟簧 , Force attenuation due to stress relaxation of the lock hook △FR 锁钩 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve 偏心套 And the deformation of the shell △L 壳体 Related; An initial data storage device, used to store a preset initial tension P, expected life, time point t during the test, and tension attenuation ΔP of each tension attenuation deformation body measured at each time point for the tension attenuation test of the space docking lock system, wherein the test is performed at N different test temperatures, the N test temperatures are all greater than room temperature, N≥2, a certified load is continuously loaded for a certain period of time at each test temperature, and the tension attenuation ΔP of each tension attenuation deformation body is measured at each time point t after a predetermined period of time at each temperature, wherein the certified load is a load that maintains the initial tension P; A first fitter is used to obtain the decay rate B at the engineering temperature and the 1-hour decay rate A at the engineering temperature through curve fitting and linear fitting according to the time point t and the tension decay at N different test temperatures stored in the initial data storage device; A tension attenuation value module for the expected working life at the engineering temperature, in which a second rule is embedded, and the second rule is related to the attenuation rate B at the engineering temperature and the 1-hour attenuation rate A at the engineering temperature obtained by the first fitter; The force attenuation calculation device is used to obtain the force attenuation △FR caused by the stress relaxation of the disc spring through the tension attenuation value module during the expected working life at engineering temperature 碟簧 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve 偏心套 , Force attenuation due to stress relaxation of the lock hook △FR 锁钩 ; The equivalent deformation coefficient calculation device is used to obtain the equivalent stiffness K of the disc spring according to the approved load and the static stiffness of the disc spring, eccentric sleeve, and lock hook at the engineering temperature and the initial tension deformation under the approved load. 碟簧 , Equivalent stiffness K of eccentric sleeve 偏心套 , equivalent stiffness K of the lock hook 锁钩 ; The shell deformation calculation device is used to obtain the shell deformation △L according to the Young's modulus of the shell material and the initial tension P 壳 body; The space docking lock system tension attenuation calculation device is used to obtain the data obtained by the force attenuation calculation device, the equivalent deformation coefficient calculation device, and the shell deformation calculation device, and use the space docking lock system tension attenuation simplified module to obtain the tension attenuation of the space docking lock system under the expected service life.

[0011] Preferably, the first embedded rule is: Among them, △F 单套对接锁 is the tension attenuation of the space docking lock system, K 锁钩 is the equivalent stiffness of the lock hook, K 偏心套 is the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K is the force attenuation caused by the stress relaxation of the disc spring. 碟簧 is the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by stress relaxation of the lock hook. 偏心套 is the force attenuation caused by the stress relaxation of the eccentric sleeve, △L 壳体 is the deformation of the shell.

[0012] Preferably, the initial tension recorded in the initial data storage device is 37 kN, the expected life is 15 years, the N different temperatures are 85°C, 115°C, 145°C and 175°C, and the tension attenuation of each tension attenuation deformable body is measured and recorded every 5 hours at each temperature.

[0013] Preferably, the first fitter comprises: A temperature decay rate calculator, for drawing a tension decay amount-time logarithmic relationship curve according to the measurement time point t and the tension decay amount ΔP at N different test temperatures, and fitting the slope using the least square method in combination with the linear relationship between the tension decay amount and the time logarithm, wherein the slope is the decay rate Vsn at the test temperature; The average decay rate calculator is used to draw the force decay rate-temperature reciprocal relationship curve at different test temperatures, and to fit the slope of the decay rate and the reciprocal of the temperature in combination with the linear relationship between the decay rate and the reciprocal of the temperature. The slope of the decay rate and the reciprocal of the temperature is the average decay rate; Engineering temperature decay rate calculator, used to draw the logarithm of the average decay rate-the inverse of the temperature relationship curve according to the average decay rate, and combine the linear relationship between the logarithm of the average decay rate and the inverse of the temperature, use the least squares method to fit the linear relationship between the logarithm of the average decay rate and the inverse of the temperature, and obtain the decay rate B at the engineering temperature; The 1-hour attenuation rate calculator at engineering temperature is used to plot the logarithm of the 1-hour attenuation rate versus the inverse of temperature. Combined with the linear relationship between the logarithm of the 1-hour attenuation rate and the inverse of temperature, the intercept obtained by fitting is the 1-hour attenuation rate A at engineering temperature.

[0014] Preferably, the second rule is: △P=A+Blnt,B=V s ; Where ΔP is the tension attenuation, A is the 1-hour attenuation rate at engineering temperature, B is the attenuation rate at engineering temperature, t is time, V s is the stress relaxation rate at engineering temperature.

[0015] Preferably, the space docking lock system tension attenuation determination device also includes a tension attenuation comparison device, which is used to compare the obtained tension attenuation value of the space docking lock system under the expected life span with a preset tension attenuation threshold value. If the obtained tension attenuation value of the space docking lock system under the expected life span is not higher than the preset tension attenuation threshold value, the output is qualified.

[0016] The beneficial effects of the present invention are as follows: through the analysis and simplification of the force transmission path of the space docking lock system, the determination and conservative analysis of the small deformation parts in the space docking lock system, and the tension attenuation assumption, a prediction model for the life of the space docking lock system is established, and by measuring the force deformation of each tension attenuation deformation body in the space docking lock system at different time points, the parameters in the model are determined using methods such as linear fitting, so as to analyze the tension attenuation data required for the service life of the space docking lock system. Through the method and device of the present invention, it is possible to accurately judge whether the space docking lock system can meet the expected service life when the tension stress decays under space conditions based on ground tests, and the result is more accurate and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the space docking lock system structure of the present invention.

[0018] Figure 2 This is the experimental stress relaxation curve of disc spring.

[0019] Figure 3 This is the tension attenuation curve of the disc spring at 85°C.

[0020] Figure 4 This is the tension attenuation curve of disc spring at 115℃.

[0021] Figure 5 This is the tension attenuation curve of disc spring at 145℃.

[0022] Figure 6 This is the tension attenuation curve of disc spring at 175℃.

[0023] Figure 7 This is the relationship curve between the stress relaxation rate of disc spring and temperature.

[0024] Figure 8 This is the relationship curve between the tension attenuation and temperature after the disc spring stress relaxes for 1 hour.

[0025] The reference numerals in the drawings of the specification are: 1 is a locking nut, 2 is a guide sleeve, 3 is a passive locking pin, 4 is an explosive bolt, 5 is a housing, 6 is a support plate, 7 is a passive locking hook, 8 is an eccentric shaft, 9 is a disc spring, 10 is a lower guide sleeve, 11 is an active locking hook, 12 is an active locking pin, and 13 is an eccentric sleeve. DETAILED DESCRIPTION

[0026] The present invention will be described below based on examples, but the present invention is not limited only to these examples.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Firstly, the active lock hook, passive lock hook, disc spring, eccentric sleeve and shell in the space docking lock system are set as tension attenuation deformation bodies. Based on the force relationship between the deformation bodies after the space docking lock system is docked, a simplified module of the space docking lock system with the first rule embedded is constructed. The equivalent stiffness K of the simplified module of the space docking lock system and the lock hook is 锁钩 , Equivalent stiffness K of eccentric sleeve 偏心套 , Force attenuation △FR caused by stress relaxation of disc spring 碟簧 , Equivalent stiffness K of disc spring 碟簧 , Force attenuation due to stress relaxation of the lock hook △FR 锁钩 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve 偏心套 And the deformation of the shell △L 壳体 Related. Specifically as follows: the space docking lock system mainly includes a locking nut 1, an upper guide sleeve 2, a disc spring 9, a lower guide sleeve 10, a passive lock hook 7, an active lock hook 11, an active lock pin 12, an eccentric sleeve 13, an eccentric shaft 8, a support plate 6, a passive lock pin 3, an explosive bolt 4 and a housing 5. During the locking process of the space docking lock system, the active lock hook 11 is driven by the eccentric shaft to move in the locking direction to form a connection with the passive lock hook 7. As the active lock hook 11 continues to move, the disc spring 9 is compressed to generate tension and maintain it.

[0032] Establish and simplify the force transmission model of the space docking lock system: When the space docking lock system is locked and no stress relaxation occurs, the lock system tension should meet the initial value, such as the preset 37kN (constant load). The active lock hook force transmission path and the passive lock hook force transmission path are the main parts of the space docking lock system tension transmission path. Through the analysis of the space docking lock system structure, the active lock hook force transmission path is simplified to the active lock hook 11, the active lock pin 12, the eccentric sleeve 13, the eccentric shaft 8 and the shell 5. Similarly, the force transmission path of the passive lock hook is simplified to the passive lock hook 7, the lower guide sleeve 10, the disc spring 9, the upper guide sleeve 2, the locking nut 1, the support plate 6, the passive pin lock 3, the explosive bolt 4 and the shell 5.

[0033] In order to establish a long-life prediction model for space docking locks, some assumptions and simplifications are also required, including the assumptions of rigid bodies and deformable bodies in the process of simplifying the force transmission path: the parts with large deformations simplified as elastic bodies in the model include: housing 5, passive lock hook 7, disc spring 9, active lock hook 11, eccentric sleeve 13; the parts with small deformations that have little effect on the space docking lock system in the model are simplified as rigid bodies including: locking nut 1, upper guide sleeve 2, eccentric shaft 8, lower guide sleeve 10, active lock pin 12.

[0034] After the active and passive lock hooks of the space docking lock system are locked, the active lock hook 11 and the passive lock hook 7 remain connected and stretched against each other under the tension of the eccentric shaft 8 and the disc spring 9, and the active and passive lock hooks are regarded as a whole. Therefore, after the stress of the disc spring 9 is relaxed, the tension acting on the active and passive lock hooks will decrease, resulting in a decrease in deformation, which can be expressed as: △F 锁钩 =K 锁钩 △L 锁钩 (1);

[0035] Among them, △F 锁钩 is the load change of the lock hook, K 锁钩 is the equivalent stiffness of the lock hook, △L 锁钩 is the elastic deformation of the lock hook.

[0036] After the space docking lock system is locked, the parts used to fix the space docking lock system to the shell 5 transfer the tension to the shell, and the shell ensures the connection of the space station docking mechanism, so the shell 5 is deformed.

[0037] After the space docking lock system is locked, stress relaxation occurs very slowly, so the entire lock system is in a state of static equilibrium, that is, it satisfies: F 碟簧 =F 锁钩 =F 偏心套 =F 壳体 (2);

[0038] Among them, F 碟簧 is the force borne by the disc spring, F 锁钩 is the force on the lock hook, F 偏心套 is the force borne by the eccentric sleeve, F 壳体 is the force borne by the shell.

[0039] When the disc spring 9 of the space docking lock system relaxes its stress, the force of the space docking lock system will be rebalanced, and the force on each part will remain equal. Therefore, the load change, that is, the tension attenuation, is also equal, that is: △F 碟簧 =△F 锁钩 =△F 偏心套 =△F 壳体 (3);

[0040] Among them, △F 碟簧 is the load variation of the disc spring, △F 锁钩 is the load change of the lock hook, △F 偏心套 is the load variation of the eccentric sleeve, △F 壳体 is the load variation of the shell.

[0041] Based on the above content, the force balance equation is reestablished as follows: △F 单套对接锁 =△F 碟簧 = △FR 碟簧 -K 碟簧 △L 碟簧 ; △F 单套对接锁 =△F 锁钩 = △FR 锁钩 -K 锁钩 △L 锁钩 ; (4); △F 单套对接锁 =△F 偏心套 = △FR 偏心套 -K 偏心套 △L 偏心套 ; Among them, △F 单套对接锁 K is the load variation of a single set of docking locks, i.e. the tension attenuation, 锁钩 is the equivalent stiffness of the lock hook, K 偏心套 is the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K is the force attenuation caused by the stress relaxation of the disc spring. 碟簧 is the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by stress relaxation of the lock hook. 偏心套 is the force attenuation caused by the stress relaxation of the eccentric sleeve, △L 碟簧 is the deformation of the disc spring, △L 锁钩 is the deformation of the lock hook, △L 偏心套 is the deformation of the eccentric sleeve.

[0042] The deformation caused by the tension attenuation of the space docking lock system can be expressed as: △L 碟簧 =△L 锁钩 +△L 偏心套 +△L 壳体 (5); Where: △L 壳体 is the deformation of the shell.

[0043] Combining the force balance equation and the deformation equation, a tension attenuation model of the space docking lock system after a long service period can be established, that is, a simplified module of tension attenuation of the space docking lock system:

[0044] The above formula is the first rule. According to the first rule, a simplified tension attenuation module of the space docking lock system can be constructed, where △F 单套对接锁 is the tension attenuation of the space docking lock system, K 锁钩 is the equivalent stiffness of the lock hook, K 偏心套is the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K is the force attenuation caused by the stress relaxation of the disc spring. 碟簧 is the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by stress relaxation of the lock hook. 偏心套 is the force attenuation caused by the stress relaxation of the eccentric sleeve, △L 壳体 is the deformation of the shell.

[0045] Using the simplified tension decay module to predict the stress relaxation of a single set of docking locks in service, it is necessary to determine the equivalent stiffness K of the lock hook. 锁钩 , Equivalent stiffness K of eccentric sleeve 偏心套 , Force attenuation △FR caused by stress relaxation of disc spring 碟簧 , Equivalent stiffness K of disc spring 碟簧 , Force attenuation due to stress relaxation of the lock hook △FR 锁钩 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve 偏心套 , shell deformation △L 壳体 And other 7 physical quantities.

[0046] Another step is: setting the initial tension P, expected life and N different test temperatures for the tension attenuation test of the space docking lock system, wherein the N test temperatures are all greater than room temperature, N≥2, continuously loading the approved load for a certain period of time at each test temperature, and measuring the tension attenuation ΔP of each tension attenuation deformable body at each time point t after a predetermined period of time at each temperature, wherein the approved load is a load that maintains the initial tension P.

[0047] The details are as follows: The initial tension is set to 37 kN, the expected life is 15 years, the N different temperatures are 85° C., 115° C., 145° C. and 175° C., and the tension attenuation of each tension attenuation deformable body is measured and recorded every 5 hours at each temperature.

[0048] Another step is: according to the obtained time point t at multiple different test temperatures and the tension attenuation at the time point, the attenuation rate B at the engineering temperature and the 1-hour attenuation rate A at the engineering temperature are obtained through curve fitting and linear fitting.

[0049] Another step is: according to the attenuation rate B at the engineering temperature and the 1-hour attenuation rate A at the engineering temperature, a tension attenuation value module of the tension attenuation deformation body embedded with the second rule is constructed when the expected service life of the tension attenuation deformation body is at the engineering temperature; another step is: the expected service life is input into the tension attenuation value modules of the disc spring, the eccentric sleeve, and the lock hook respectively, and the force attenuation amount △FR caused by the stress relaxation of the disc spring is obtained 碟簧 , Force attenuation △FR caused by stress relaxation of the eccentric sleeve偏心套 , Force attenuation due to stress relaxation of the lock hook △FR 锁钩 .

[0050] The details are as follows: The force attenuation caused by the stress relaxation of the disc spring is determined according to the Arrhenius formula: Where V s It is the performance degradation index of the test piece, which can indicate the speed of tension relaxation of the space docking lock system. In the present invention, it is the stress relaxation rate at engineering temperature, which is defined as Vs = d(ΔP) / d(lnt). Q is a constant related to the initial load of stress relaxation and the disc spring itself; γ is a constant, k is the Boltzmann constant, and T is the test stress expressed in absolute temperature.

[0051] Taking the logarithm of both sides of the above equation gives: LqCy s =lnγ-Q / kT (8); That is lnV s It is linearly related to 1 / T. s ~1 / T for curve fitting, the stress relaxation rate V of the disc spring at the engineering temperature can be obtained s . Through V s Based on the definition of , the linear fitting formula of tension attenuation can be established as: ΔP=A+Blnt,B=V S (9); The above formula is the second rule. According to the second rule, a tension attenuation value module can be constructed for the tension attenuation deformation body including the lock hook, disc spring, eccentric sleeve and shell when the expected service life is at the engineering temperature, which is embedded with the second rule. Among them, ΔP is the tension attenuation, A is the 1-hour attenuation rate at the engineering temperature, B is the attenuation rate at the engineering temperature, t is the time, V s is the stress relaxation rate at engineering temperature.

[0052] The stress relaxation test of the space docking lock system is carried out at 85℃, 115℃, 145℃ and 175℃ respectively. Then the load P~t curves at 85℃, 115℃, 145℃ and 175℃ can be obtained through the stress relaxation test, such as Figure 2 As shown, the ΔP-lnt curves at different temperatures are drawn respectively, as shown in Figure 3-6 As shown. Figure 3-6 The fitting equation and coefficients obtained by linear fitting are shown in Table 1.

[0053] Table 1: Disc spring stress relaxation fitting equation

[0054] After obtaining Table 1, we can plot lnV s ~1 / T curve is as follows Figure 7 As shown, the equation of the straight line is deduced as:

[0055] The stress relaxation rate at room temperature (298K) is deduced and substituted into the above formula to obtain:

[0056] To calculate A in the linear fitting formula, we can set t = 1h and use the definition of Vs to obtain:

[0057] Taking the logarithm of both sides gives: lnA=a / T+b (13); That is, lnA and 1 / T are in a linear relationship. The linear fitting interpolation method is also used to calculate the coefficient of A at room temperature. The 1h disc spring tension decay rate is organized into Table 2, and the lnA~1 / T curve is plotted at the same time, as shown in Table 2. Figure 8 shown.

[0058] Table 2: Disc spring tension decay rate at t = 1h

[0059] right Figure 8 After fitting the image, the equation of the straight line is: It is calculated that at room temperature T = 298K, A = 0.1352. Input A and B at room temperature into the disc spring force attenuation module to calculate the force attenuation △FR caused by the stress relaxation of the disc spring. 碟簧 =3191.3101N.

[0060] The force attenuation of the eccentric sleeve and the lock hook can be determined by the same determination method as the disc spring. The stress relaxation curves of titanium alloy TC4R and titanium alloy TB2 at four temperatures of 85℃, 115℃, 145℃ and 175℃ are used to calculate the force attenuation of the eccentric sleeve and the lock hook. The force attenuation caused by the stress relaxation of the eccentric sleeve is obtained as △FR 偏心套 =3423.04N, force attenuation due to stress relaxation of the lock hook △FR 锁钩 =3005.05N.

[0061] Another step is: according to the rated load and the static stiffness of the disc spring, the eccentric sleeve, and the lock hook at the engineering temperature, and the initial tension deformation under the rated load, the equivalent stiffness K of the disc spring is obtained. 弹簧 , Equivalent stiffness K of eccentric sleeve偏心套 , equivalent stiffness K of the lock hook 锁钩 .

[0062] The details are as follows: When stress relaxation occurs in disc springs, only stress decreases while deformation remains unchanged. Then the deformation can be calculated using the stress when stress relaxation does not occur and the stiffness at room temperature. The static stiffness test of the disc spring is carried out at room temperature. The disc spring is tensioned by a force loading mechanism. The tension value F and the corresponding deformation Δl are recorded, and the F-Δl curve is plotted. The slope of F-Δl obtained by the static stiffness test is fitted, and the average value is taken to obtain the disc spring stiffness E of 20582N / mm. The initial deformation of the disc spring can be calculated by the static stiffness: Δl=P 0 / E=1.7977mm (15); P 0 is the unrelaxed tension value of the disc spring, which is 37kN. Then the calculation formula for the equivalent stiffness is:

[0063] The equivalent stiffness of the eccentric sleeve and the lock hook can be determined by using the same determination method as the disc spring, and a static stiffness test is performed. The two are loaded by a loading mechanism and calculated to obtain: K 偏心套 =506792N / mm, K 锁钩 =44014.08N / mm (17).

[0064] Another step is to obtain the deformation ΔL of the shell according to the Young's modulus of the shell material and the initial tension P. 壳体 The details are as follows: Shell deformation ΔL 壳体 , obtained by finite element analysis of the shell through tensile test and creep test data of the shell material (for example, 7A04). First, the stress relaxation of the shell is calculated using the fitting method, and then the deformation of the shell ΔL is calculated 壳体 =0.01314mm.

[0065] Another step is: input the parameters required by the space docking lock system tension decay simplification module to obtain the tension decay value of the space docking lock system under the expected life span. The details are as follows: The above determined data is brought into the simplified module of tension attenuation of the space docking lock system, and it is calculated that when the initial tension is 37kN, the room temperature is 25°C, the service life is 15 years, the docking lock tension attenuation value is 2.453kN, the attenuation rate is 6.629%, the remaining locking force is 34.547kN, and the preset tension attenuation threshold is 30kN. It is judged that the service life of the space docking lock system meets the requirements.

[0066] It should be noted that the device for determining the tension attenuation of the docking lock system under the expected service life of the present invention is arranged based on the ability to implement all or part of the above-mentioned method. Those skilled in the art can fully adapt the system and the devices constituting the system as the above-mentioned method is adjusted. Therefore, various possible deformations of the device for determining the tension attenuation of the docking lock system under the expected service life and the various parts constituting the device are not described in detail.

[0067] 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 determining the attenuation of the tension of a docking lock system under expected service life, characterized in that: The following steps are involved: Step S100: The active lock hook, the passive lock hook, the disc spring, the eccentric sleeve and the housing in the space docking lock system are set as tension attenuation deformation bodies. Based on the force relationship between the deformation bodies after the space docking lock system is docked, a space docking lock system tension attenuation simplified module embedded with the first rule is constructed. The space docking lock system tension attenuation simplified module and the lock hook have an equivalent stiffness of K 锁钩 , Equivalent stiffness of eccentric sleeve K 偏心套 , the stress relaxation of the disc spring causes the force attenuation △ FR 碟簧 , Equivalent stiffness of disc spring K 碟簧 , Force attenuation caused by stress relaxation of the lock hook△ FR 锁钩 , Force attenuation caused by stress relaxation of the eccentric sleeve△ FR 偏心套 And the deformation of the shell △ L 壳体 Related; Step S200: Setting the initial tension of the space docking lock system tension decay test P , expected life and N different test temperatures, N of the test temperatures are all greater than room temperature, N ≥ 2, the rated load is continuously applied for a certain period of time at each test temperature, and the tension attenuation Δ of each tension attenuation deformable body is measured at each time point t after a predetermined period of time at each test temperature P , wherein the rated load is to maintain the initial tension P Load; Step S300: According to the time point t and the tension attenuation at the N different test temperatures obtained in step S200, the attenuation rate at the engineering temperature is obtained by curve fitting and linear fitting. B And the 1-hour decay rate at engineering temperature A ; Step S400: Attenuation rate at the engineering temperature obtained in step S300 B And the 1-hour decay rate at engineering temperature A , constructing a tension attenuation value module embedded with the second rule for the tension attenuation deformable body during its expected working life at engineering temperature; Step S500: Input the expected life into the tension attenuation value modules of the disc spring, eccentric sleeve, and lock hook constructed in step S400 to obtain the force attenuation caused by the stress relaxation of the disc spring △ FR 碟簧 , Force attenuation caused by stress relaxation of the eccentric sleeve△ FR 偏心套 , Force attenuation caused by stress relaxation of the lock hook△ FR 锁钩 ; Step S600: Obtain the equivalent stiffness of the disc spring according to the rated load, the static stiffness of the disc spring, the eccentric sleeve, and the lock hook at the engineering temperature, and the initial tension deformation under the rated load. K 碟簧 , Equivalent stiffness of eccentric sleeve K 偏心套 , Equivalent stiffness of the lock hook K 锁钩 ; Step S700: According to the Young's modulus and initial tension of the shell material P The deformation of the shell is obtained L 壳体 ; Step S800: Input the values ​​obtained in steps S500-S700 into the simplified module of tension attenuation of the space docking lock system constructed in step S100 to obtain the tension attenuation of the space docking lock system under the expected lifespan.

2. The method for determining the attenuation of the tension of the docking lock system under the expected service life according to claim 1, characterized in that: The first rule in step S100 is: ； Among them, △ F 单套对接锁 is the tension attenuation of the space docking lock system, K 锁钩 is the equivalent stiffness of the lock hook, K 偏心套 is the equivalent stiffness of the eccentric sleeve, △ FR 碟簧 is the force attenuation caused by the stress relaxation of the disc spring, K 碟簧 is the equivalent stiffness of the disc spring, △ FR 锁钩 is the force attenuation caused by the stress relaxation of the lock hook, △ FR 偏心套 is the force attenuation caused by the stress relaxation of the eccentric sleeve, △ L 壳体 is the deformation of the shell.

3. The method for determining the attenuation of the tension of the docking lock system under the expected service life according to claim 1, characterized in that: In step S200, the initial tension is 37 kN, the expected life is 15 years, the N different temperatures are 85° C., 115° C., 145° C. and 175° C., and the tension attenuation of each tension attenuation deformable body is measured and recorded every 5 hours at each temperature.

4. The method for determining the attenuation of the tension of a docking lock system under expected service life according to claim 1, characterized in that: Step S300 includes: Step S310: According to the measurement time point t and the tension attenuation Δ at N different test temperatures P , draw the tension decay-time logarithmic relationship curve, and combine the linear relationship between tension decay and time logarithm, use the least squares method to fit the slope, the slope is the decay rate at the test temperature Vsn ; Step S320: plotting the decay rate-temperature reciprocal relationship curve at different test temperatures, and fitting the slope of the decay rate and the temperature reciprocal in combination with the linear relationship between the decay rate and the temperature reciprocal, wherein the slope of the decay rate and the temperature reciprocal is the average decay rate; Step S330: Draw a curve of the logarithm of the average decay rate and the inverse of the temperature according to the average decay rate, and use the least squares method to fit the linear relationship between the logarithm of the average decay rate and the inverse of the temperature, and obtain the decay rate at the engineering temperature. B ; Step S340: Draw a curve of the logarithm of the 1-hour decay rate and the inverse of the temperature. Combined with the linear relationship between the logarithm of the 1-hour decay rate and the inverse of the temperature, the intercept obtained by fitting is the 1-hour decay rate at the engineering temperature. A .

5. The method for determining the attenuation of the tension of a docking lock system under expected service life according to claim 1, characterized in that: The embedded second rule in step S400 is: △ P = A+B ln t,B=V s ； Among them, △ P is the tension attenuation, A is the 1-hour attenuation rate at engineering temperature, B is the decay rate at engineering temperature, t is the time, V s is the stress relaxation rate at engineering temperature.

6. The method for determining the attenuation of the tension of a docking lock system under expected service life according to claim 1, characterized in that: The obtained tension attenuation of the space docking lock system under the expected lifespan is compared with the preset tension attenuation threshold. If the obtained tension attenuation of the space docking lock system under the expected lifespan is not higher than the preset tension attenuation threshold, the output is qualified.

7. A device for determining the attenuation of the tension of a docking lock system under expected service life, characterized in that: The device comprises: A simplified module for space docking lock system tension attenuation, in which the first rule is embedded, and the simplified module for space docking lock system tension attenuation and the equivalent stiffness of the lock hook K 锁钩 , Equivalent stiffness of eccentric sleeve K 偏心套 , force attenuation caused by stress relaxation of disc spring △ FR 碟簧 , Equivalent stiffness of disc spring K 碟簧 , Force attenuation caused by stress relaxation of the lock hook△ FR 锁钩 , Force attenuation caused by stress relaxation of the eccentric sleeve△ FR 偏心套 And the deformation of the shell △ L 壳体 Related; An initial data storage device is used to store a preset initial tension of the tension decay test of the space docking lock system. P , expected life, time point t during the test, and the tension attenuation Δ of each tension attenuation deformation body measured at each time point P , wherein the test is carried out at N different test temperatures, N of which are all greater than room temperature, N≥2, and the rated load is continuously applied for a certain period of time at each test temperature, and the tension attenuation Δ of each tension attenuation deformable body is measured at each time point t after a predetermined period of time at each test temperature P , wherein the rated load is to maintain the initial tension P Load; The first fitting device is used to obtain the attenuation rate at the engineering temperature through curve fitting and linear fitting according to the time point t and the tension attenuation at N different test temperatures stored in the initial data storage device. B And the 1-hour decay rate at engineering temperature A ; A module for the tension attenuation value at the expected working life at the engineering temperature, in which the second rule is embedded, and the attenuation rate at the engineering temperature obtained by the first fitter B And the 1-hour decay rate at engineering temperature A related; The force attenuation calculation device is used to obtain the force attenuation amount △ caused by the stress relaxation of the disc spring through the tension attenuation value module during the expected working life at engineering temperature FR 碟簧 , Force attenuation caused by stress relaxation of the eccentric sleeve△ FR 偏心套 , Force attenuation caused by stress relaxation of the lock hook△ FR 锁钩 ; The equivalent deformation coefficient calculation device is used to obtain the equivalent stiffness of the disc spring according to the approved load and the static stiffness of the disc spring, eccentric sleeve, and lock hook at the engineering temperature and the initial tension deformation under the approved load. K 碟簧 , Equivalent stiffness of eccentric sleeve K 偏心套 , Equivalent stiffness of the lock hook K 锁钩 ; The shell deformation calculation device is used to calculate the shell deformation according to the Young's modulus and initial tension of the shell material. P The deformation of the shell is obtained L 壳体 ; The space docking lock system tension attenuation calculation device is used to obtain the data obtained by the force attenuation calculation device, the equivalent deformation coefficient calculation device, and the shell deformation calculation device, and use the space docking lock system tension attenuation simplified module to obtain the tension attenuation of the space docking lock system under the expected service life.

8. The device for determining the attenuation of tension of a docking lock system under expected service life according to claim 7, characterized in that: The first rule embedded is: ； Among them, △ F 单套对接锁 is the tension attenuation of the space docking lock system, K 锁钩 is the equivalent stiffness of the lock hook, K 偏心套 is the equivalent stiffness of the eccentric sleeve, △ FR 碟簧 is the force attenuation caused by the stress relaxation of the disc spring, K 碟簧 is the equivalent stiffness of the disc spring, △ FR 锁钩 is the force attenuation caused by the stress relaxation of the lock hook, △ FR 偏心套 is the force attenuation caused by the stress relaxation of the eccentric sleeve, △ L 壳体 is the deformation of the shell.

9. The device for determining the attenuation of the tension of the docking lock system under the expected service life according to claim 7, characterized in that: The initial tension recorded in the initial data storage device is 37 kN, the expected life is 15 years, the N different temperatures are 85° C., 115° C., 145° C. and 175° C., and the tension attenuation of each tension attenuation deformable body is measured and recorded every 5 hours at each temperature.

10. The device for determining the attenuation of the tension of the docking lock system under the expected service life according to claim 7, characterized in that: The first fitting device comprises: Temperature decay rate calculator, used to calculate the temperature decay rate based on the measurement time point t and tension decay value Δ at N different test temperatures P , draw the tension decay-time logarithmic relationship curve, and combine the linear relationship between tension decay and time logarithm, use the least squares method to fit the slope, the slope is the decay rate at the test temperature Vsn ; The average decay rate calculator is used to draw the force decay rate-temperature reciprocal relationship curve at different test temperatures, and to fit the slope of the decay rate and the reciprocal of the temperature in combination with the linear relationship between the decay rate and the reciprocal of the temperature. The slope of the decay rate and the reciprocal of the temperature is the average decay rate; Engineering temperature decay rate calculator, used to draw the logarithm of the average decay rate-the inverse of the temperature relationship curve based on the average decay rate, and combined with the linear relationship between the logarithm of the average decay rate and the inverse of the temperature, use the least squares method to fit the linear relationship between the logarithm of the average decay rate and the inverse of the temperature, and get the decay rate at engineering temperature B ; Engineering temperature 1 hour decay rate calculator, used to draw the logarithm of 1 hour decay rate - the inverse of temperature relationship curve, combined with the linear relationship between the logarithm of 1 hour decay rate and the inverse of temperature, the intercept obtained by fitting is the 1 hour decay rate at engineering temperature A .

11. The device for determining the attenuation of tension of a docking lock system under expected service life according to claim 7, characterized in that: The second rule embedded is: △ P = A+B ln t,B=V s ； Among them, Δ P is the tension attenuation, A is the 1-hour attenuation rate at engineering temperature, B is the decay rate at engineering temperature, t is the time, V s is the stress relaxation rate at engineering temperature.

12. The device for determining the attenuation of the space docking lock system tension under the expected life span according to claim 7, characterized in that: It also includes a tension attenuation comparison device for comparing the obtained tension attenuation of the space docking lock system under the expected lifespan with a preset tension attenuation threshold. If the obtained tension attenuation of the space docking lock system under the expected lifespan is not higher than the preset tension attenuation threshold, the output is qualified.

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