A method and apparatus for determining the tension decay of a docking locking system under expected lifespan

Abstract

This invention provides a method and apparatus for determining the tension decay of a docking lock system under its expected service life. By analyzing and simplifying the force transmission path of the space docking lock system, identifying and conservatively analyzing small deformable parts within the system, and making tension decay assumptions, this invention establishes a predictive model for the service life of the space docking lock system. By measuring the force and deformation of each tension-decaying deformable body in the space docking lock system at different time points, and using methods such as linear fitting, the parameters in the model are determined. This allows for the analysis of the tension decay data required for the service life of the space docking lock system. Using the method and apparatus of this invention, it is possible to accurately determine whether the space docking lock system can meet its expected service life under tension decay conditions in space, based on ground-based tests.

Description

Technical Field

[0001] This invention relates to the field of stress measurement, including the measurement of tension and stress decay of mechanical structures under expected service life. Specifically, it relates to determining the tension decay of the space docking lock system under actual working conditions and expected life by measuring the force decay of the main deformable components of the space docking lock system at different temperatures and time points. Background Technology

[0002] Space rendezvous and docking technology is a core technology that must be mastered in manned spaceflight. The space docking mechanism is the core device for performing space docking missions, and its research involves theories and technologies in many aspects, including mechanism design, structural analysis, dynamics, and control. The space docking lock system is an important component of the docking mechanism's mechanical components and a crucial part connecting adjacent modules of the space station. Its lifespan 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 lifespan of the space station. Research and testing of the space docking lock system's lifespan is an important part of ensuring the safe and stable operation of the space station. This is because the space docking lock system is equipped with docking hooks, including active and passive hooks. Once the tension between the hooks weakens to a safe threshold, the rigidity and sealing of the docking mechanism connection cannot be guaranteed, which may even lead to locking failure and endanger the safety of the space station. In existing technologies, the service life of mechanical structures is usually judged empirically. For mass-produced products, the service life can also be predicted by extreme testing. For example, CN112926144A discloses a method for analyzing the coupling effect and predicting the life of accelerated life tests under multiple stresses. This method is mainly a theoretical study on the coupling effect and life prediction of general mechanical mechanisms. The process is very complex and has no practical guiding significance for stress attenuation analysis of space docking lock systems. Summary of the Invention

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

[0004] This invention proposes a method for determining the tension decay of a docking locking system under expected lifespan, comprising the following steps:

[0005] Step S100: The active locking hook, passive locking hook, disc spring, eccentric sleeve, and shell in the space docking system are designated as tension-attenuating deformable bodies. Based on the force relationship between these deformable bodies after docking, a simplified tension attenuation module for the space docking system with an embedded first rule is constructed. The equivalent stiffness K of the tension attenuation module and the locking hook are... 锁钩 The equivalent stiffness K of the eccentric sleeve 偏心套 The force reduction ΔFR caused by stress relaxation of the disc spring 碟簧 The equivalent stiffness K of the disc spring 碟簧The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 and the deformation of the shell ΔL 壳体 Related;

[0006] Step S200: Set the initial tension P, expected life, and N different test temperatures for the tension decay test of the space docking locking system. All N test temperatures are greater than room temperature, and N≥2. At each test temperature, continuously apply the approved load for a certain period of time. At each test temperature, measure the tension decay amount ΔP of each tension decay deformable body at time points t after a predetermined period of time. The approved load is the load that maintains the initial tension P.

[0007] Step S300: Based on the time points t and tension decay at the N different test temperatures obtained in step S200, the decay rate B and the 1-hour decay rate A at the engineering temperature are obtained through curve fitting and linear fitting; Step S400: Based on the decay rate B and the 1-hour decay rate A at the engineering temperature obtained in step S300, a tension decay value module with embedded second rule is constructed for the expected working life of the tension decay deformable body at the engineering temperature.

[0008] Step S500: Input the expected lifespan into the respective tension attenuation value modules of the disc spring, eccentric sleeve, and locking hook constructed in step S400 to obtain the force attenuation ΔFR caused by stress relaxation of the disc spring. 碟簧 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 ;

[0009] Step S600: Based on the rated load and the static stiffness of the disc spring, eccentric sleeve, and locking hook at the engineering temperature, and the initial tension deformation under the rated load, obtain the equivalent stiffness K of the disc spring. 碟簧 The equivalent stiffness K of the eccentric sleeve 偏心套 The equivalent stiffness K of the locking hook 锁 hook;

[0010] Step S700: Obtain the deformation ΔL of the shell based on the Young's modulus of the shell material and the initial tension P. 壳体 ;

[0011] Step S800: Input the values ​​obtained in steps S500-S700 into the space docking system tension attenuation simplification module constructed in step S100 to obtain the tension attenuation of the space docking system under the expected life.

[0012] Preferably, the first rule in step S100 is:

[0013]

[0014] Among them, △F 单套对接锁 K represents the tension attenuation of the space docking locking system. 锁钩 K is the equivalent stiffness of the locking hook. 偏心套 For the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K represents the force reduction caused by stress relaxation of the disc spring. 碟簧 For the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by the stress relaxation of the locking hook. 偏心套 ΔL represents the force attenuation caused by stress relaxation of the eccentric sleeve. 壳体 This represents the deformation of the shell.

[0015] Preferably, the initial tension in S200 is 37kN, the expected life is 15 years, and N different temperatures are 85℃, 115℃, 145℃ and 175℃. At each temperature, the tension decay of each tension decay deformation body is measured and recorded every 5 hours.

[0016] Preferably, step S300 includes:

[0017] Step S310: Based on the measurement time points t and tension decay ΔP at N different test temperatures, plot the tension decay-logarithm of time relationship curve, and combine the linear relationship between tension decay and time logarithm, use the least squares method to fit the slope, where the slope is the decay rate Vsn at the test temperature;

[0018] Step S320: Plot the decay rate versus temperature reciprocal curves at different test temperatures, and combine the linear relationship between decay rate and temperature reciprocal to fit the slope of decay rate versus temperature reciprocal, where the slope of decay rate versus temperature reciprocal is the average decay rate.

[0019] Step S330: Plot the logarithm of the average decay rate versus the reciprocal of temperature based on the average decay rate. Combine the linear relationship between the logarithm of the average decay rate and the reciprocal of temperature, use the least squares method to fit the linear relationship between the logarithm of the average decay rate and the reciprocal of temperature, and obtain the decay rate B at the engineering temperature.

[0020] Step S340: Plot the logarithm of the 1-hour decay rate versus the reciprocal of temperature curve. Combine the linear relationship between the logarithm of the 1-hour decay rate and the reciprocal of temperature, and fit the intercept to obtain the 1-hour decay rate A at the engineering temperature.

[0021] Preferably, the second rule embedded in step S400 is:

[0022] △P=A+Blnt,B=V s ;

[0023] Where ΔP is the tension decay, A is the decay rate over 1 hour at the engineering temperature, B is the decay rate at the engineering temperature, t is time, and V is... s The stress relaxation rate is the stress relaxation rate at the engineering temperature.

[0024] Preferably, the tension attenuation of the space docking lock system under the expected lifespan is compared with a preset tension attenuation threshold. If the tension attenuation of the space docking lock system under the expected lifespan is not higher than the preset tension attenuation threshold, then the output is qualified.

[0025] The present invention also proposes a device for determining the tension decay of a docking locking system under expected lifespan, the device comprising:

[0026] A simplified tension attenuation module for spatial docking locking systems, which incorporates a first rule, and the equivalent stiffness K of the spatial docking locking system tension attenuation module and the locking hook. 锁钩 The equivalent stiffness K of the eccentric sleeve 偏心套 The force reduction ΔFR caused by stress relaxation of the disc spring 碟簧 The equivalent stiffness K of the disc spring 碟簧 The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 and the deformation of the shell ΔL 壳体 Related;

[0027] An initial data storage device is used to store the preset initial tension P, expected life, time point t during the test, and tension attenuation amount ΔP of each tension attenuation deformable body measured at each time point for the tension attenuation test of the space docking locking system. The test is conducted at N different test temperatures, all of which are greater than room temperature, and N≥2. A rated load is continuously applied for a certain duration at each test temperature. The tension attenuation amount ΔP of each tension attenuation deformable body is measured at time point t after a predetermined duration at each temperature. The rated load is the load that maintains the initial tension P.

[0028] The 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 by curve fitting and linear fitting based on the time points t and tension decay amount at N different test temperatures stored in the initial data storage device.

[0029] The tension decay value module at the expected working life under engineering temperature has a second rule embedded in it, which is related to the decay rate B at engineering temperature and the 1-hour decay rate A at engineering temperature obtained by the first fitter.

[0030] The force attenuation calculation device is used to obtain the force attenuation ΔFR caused by stress relaxation of the disc spring through the tension attenuation value module during the expected operating life at engineering temperature. 碟簧 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 ;

[0031] The equivalent deformation coefficient calculation device is used to obtain the equivalent stiffness K of the disc spring based on the rated load and the static stiffness of the disc spring, eccentric sleeve, and locking hook at the engineering temperature, as well as the initial tension deformation under the rated load. 碟簧 The equivalent stiffness K of the eccentric sleeve 偏心套 The equivalent stiffness K of the locking hook 锁钩 ;

[0032] A shell deformation calculation device is used to calculate the deformation ΔL of the shell based on the Young's modulus of the shell material and the initial tension P. 壳 body;

[0033] The space docking lock system tension attenuation calculation device is used to acquire the data obtained by the force attenuation calculation device, the equivalent deformation coefficient calculation device, and the shell deformation calculation device, and to obtain the tension attenuation of the space docking lock system under the expected life using the space docking lock system tension attenuation simplification module.

[0034] Preferably, the embedded first rule is:

[0035]

[0036] Among them, △F 单套对接锁 K represents the tension attenuation of the space docking locking system. 锁钩 K is the equivalent stiffness of the locking hook. 偏心套 For the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K represents the force reduction caused by stress relaxation of the disc spring. 碟簧 For the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by the stress relaxation of the locking hook. 偏心套 ΔL represents the force attenuation caused by stress relaxation of the eccentric sleeve. 壳体 This represents the deformation of the shell.

[0037] Preferably, the initial tension recorded by the initial data storage device is 37kN, the expected lifespan is 15 years, and the tension attenuation of each tension attenuation deformation body is measured and recorded every 5 hours at N different temperatures of 85℃, 115℃, 145℃ and 175℃.

[0038] Preferably, the first fitter includes:

[0039] The temperature decay rate calculator is used to plot the tension decay rate versus logarithmic time relationship curve based on the measurement time point t and tension decay rate ΔP at N different test temperatures, and to fit the slope using the least squares method in combination with the linear relationship between tension decay rate and logarithmic time. The slope is the decay rate Vsn at the test temperature.

[0040] The average decay rate calculator is used to plot the force decay rate versus temperature reciprocal curve at different test temperatures. It also combines the linear relationship between the decay rate and the temperature reciprocal to fit the slope of the decay rate versus the temperature reciprocal, which is the average decay rate.

[0041] The Engineering Temperature Decay Rate Calculator is used to plot the logarithm of the average decay rate versus the reciprocal of temperature curve based on the average decay rate. It also combines the linear relationship between the logarithm of the average decay rate and the reciprocal of temperature, and uses the least squares method to fit the linear relationship between the logarithm of the average decay rate and the reciprocal of temperature to obtain the decay rate B at the engineering temperature.

[0042] The 1-hour decay rate calculator for engineering temperature is used to plot the logarithm of the 1-hour decay rate versus the reciprocal of temperature curve. Combining the linear relationship between the logarithm of the 1-hour decay rate and the reciprocal of temperature, the intercept obtained by fitting is the 1-hour decay rate A at the engineering temperature.

[0043] Preferably, the second rule is:

[0044] △P=A+Blnt,B=V s ;

[0045] Where ΔP is the tension decay, A is the decay rate over 1 hour at the engineering temperature, B is the decay rate at the engineering temperature, t is time, and V is... s The stress relaxation rate is the stress relaxation rate at the engineering temperature.

[0046] Preferably, the space docking lock system tension attenuation determination device further includes a tension attenuation comparison device, used to compare the obtained tension attenuation value of the space docking lock system under the expected life with a preset tension attenuation threshold. If the obtained tension attenuation value of the space docking lock system under the expected life is not higher than the preset tension attenuation threshold, then the output is qualified.

[0047] The beneficial effects of this invention are as follows: By analyzing and simplifying the force transmission path of the space docking locking system, and determining and conservatively analyzing small deformable parts in the space docking locking system and using the tension decay assumption, a predictive model for the service life of the space docking locking system is established. Furthermore, by measuring the force deformation of each tension decaying deformable body in the space docking locking system at different time points, and using methods such as linear fitting, the parameters in the model are determined, thereby analyzing the tension decay data required for the service life of the space docking locking system. Through the method and apparatus of this invention, it is possible to accurately determine whether the space docking locking system can meet the expected service life under tension stress decay conditions in space, based on ground tests, resulting in more accurate and safer results. Attached Figure Description

[0048] Figure 1 This is a simplified diagram of the space docking locking system structure of the present invention.

[0049] Figure 2 This is the stress relaxation curve from a disc spring experiment.

[0050] Figure 3 The curve shows the tension decay of the disc spring at 85℃.

[0051] Figure 4 The tension decay curve of the disc spring at 115℃ is shown.

[0052] Figure 5 The curve shows the tension decay of the disc spring at 145℃.

[0053] Figure 6 The curve shows the tension decay of the disc spring at 175℃.

[0054] Figure 7 This is a curve showing the relationship between the stress relaxation rate and temperature of a disc spring.

[0055] Figure 8 The curve shows the relationship between the tension decay and temperature after 1 hour of stress relaxation of the disc spring.

[0056] The reference numerals in the accompanying drawings are as follows: 1 is the locking nut, 2 is the guide sleeve, 3 is the passive locking pin, 4 is the explosion bolt, 5 is the housing, 6 is the support plate, 7 is the passive locking hook, 8 is the eccentric shaft, 9 is the disc spring, 10 is the lower guide sleeve, 11 is the active locking hook, 12 is the active locking pin, and 13 is the eccentric sleeve. Detailed Implementation

[0057] The present invention will be described below based on embodiments, but the present invention is not limited to these embodiments.

[0058] It should be understood that the terms "first," "second," etc., used in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0059] It should be noted that the use of step numbers to refer to certain specific method steps in this invention is merely for the purpose of convenience and brevity in description, and is by no means intended to restrict the order of these method steps using 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 unduly restricted by the existence of step numbers. Those skilled in the art can determine various permissible and reasonable orderings of steps based on the technology itself.

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only for illustrative purposes and are not intended to limit the invention. Furthermore, it should be noted that since the technical solutions of this invention have already been clearly described in the summary section, the overall solution will not be repeated in the specific embodiments; only a part of the specific experimental process is described to illustrate the implementation process of the technical solutions of this invention.

[0061] In this invention, room temperature is 25°C or 298K. Engineering temperature is the equivalent temperature during actual operation of the equipment; in this embodiment, the engineering temperature is equal to room temperature.

[0062] First, the active locking hook, passive locking hook, disc spring, eccentric sleeve, and shell in the space docking system are defined as tension-attenuating deformable bodies. Based on the force relationship between the deformable bodies after docking, a simplified tension attenuation module for the space docking system with an embedded first rule is constructed. The equivalent stiffness K of the space docking system tension attenuation simplified module and the locking hook are... 锁钩 The equivalent stiffness K of the eccentric sleeve 偏心套 The force reduction ΔFR caused by stress relaxation of the disc spring 碟簧 The equivalent stiffness K of the disc spring 碟簧 The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 and the deformation of the shell ΔL 壳体 Related. Specifically, the space docking locking system mainly includes a locking nut 1, an upper guide sleeve 2, a disc spring 9, a lower guide sleeve 10, a passive locking hook 7, an active locking hook 11, an active locking pin 12, an eccentric sleeve 13, an eccentric shaft 8, a support plate 6, a passive locking pin 3, an explosion bolt 4, and a housing 5. During the locking process, the active locking hook 11 is driven by the eccentric shaft to move in the locking direction and connect with the passive locking hook 7. As the active locking hook 11 continues to move, the disc spring 9 is compressed, generating tension and maintaining its position.

[0063] A simplified force transmission model for the space docking locking system is established: When the space docking locking system is locked and no stress relaxation occurs, the locking tension should meet the initial value, for example, a preset 37kN (constant load). The force transmission paths of the active and passive locking hooks are the main parts of the tension transmission path of the space docking locking system. Through analysis of the space docking locking system structure, the force transmission path of the active locking hook is simplified to active locking hook 11, active locking pin 12, eccentric sleeve 13, eccentric shaft 8, and housing 5. Similarly, the force transmission path of the passive locking hook is simplified to passive locking hook 7, lower guide sleeve 10, disc spring 9, upper guide sleeve 2, locking nut 1, support plate 6, passive pin lock 3, explosion bolt 4, and housing 5.

[0064] To establish a long-life prediction model for space docking locking systems, some assumptions and simplifications are necessary. These include the assumptions about rigid and deformable bodies in the force transmission path simplification process: Parts with large deformations in the model are simplified to elastic bodies: shell 5, passive locking hook 7, disc spring 9, active locking hook 11, and eccentric sleeve 13; Parts with small deformations affecting the space docking locking system in the model are simplified to rigid bodies: locking nut 1, upper guide sleeve 2, eccentric shaft 8, lower guide sleeve 10, and active locking pin 12.

[0065] After the active and passive locking hooks of the spatial docking locking system are locked, the active hook 11 and the passive hook 7 remain connected and stretched together under the tension of the eccentric shaft 8 and the disc spring 9, treating the active and passive hooks as a single unit. Therefore, after the stress on the disc spring 9 relaxes, the tension acting on the active and passive hooks will decrease, resulting in a decrease in deformation, expressed as:

[0066] △F 锁钩 =K 锁钩 △L 锁钩 (1)；

[0067] Among them, △F 锁钩 K represents the change in load on the locking hook. 锁钩 For the equivalent stiffness of the locking hook, △L 锁钩 This represents the elastic deformation of the locking hook.

[0068] After the space docking lock system is locked, the parts used to fix the space docking lock system to the shell 5 will transmit the tension to the shell, and the shell will ensure the connection of the space station docking mechanism, thus causing deformation on the shell 5.

[0069] After the space docking locking system is fully engaged, stress relaxation occurs very slowly. Therefore, the entire locking system is in a state of static equilibrium, satisfying the following:

[0070] F 碟簧 =F 锁钩 =F 偏心套 =F 壳体 (2)；

[0071] Among them, F 碟簧 F is the force that the disc spring bears. 锁钩 F is the force borne by the locking hook. 偏心套 For the force borne by the eccentric sleeve, F 壳体 The force borne by the shell.

[0072] When the disc spring 9 of the space docking locking system experiences stress relaxation, it will cause the space docking locking system to rebalance its forces. The forces on each component will remain equal, therefore, the load change, i.e., the tension decrease, will also be equal.

[0073] △F 碟簧 =△F 锁钩 =△F 偏心套 =△F 壳体 (3);

[0074] Among them, △F 碟簧 Let ΔF be the change in load on the disc spring. 锁钩 Let ΔF be the change in load on the locking hook. 偏心套 The load variation of the eccentric sleeve is ΔF. 壳体 This represents the change in load on the shell.

[0075] Based on the above, the force balance equations can be re-established as follows:

[0076] △F 单套对接锁 =△F 碟簧 =△FR 碟簧 -K 碟簧 △L 碟簧 ;

[0077] △F 单套对接锁 =△F 锁钩 =△FR 锁钩 -K 锁钩 △L 锁钩 (4);

[0078] △F 单套对接锁 =△F 偏心套 =△FR 偏心套 -K 偏心套 △L 偏心套 ;

[0079] Among them, △F 单套对接锁 K represents the load change, or tension attenuation, of a single set of docking locks. 锁钩 K is the equivalent stiffness of the locking hook. 偏心套 For the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K represents the force reduction caused by stress relaxation of the disc spring. 碟簧 For the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by the stress relaxation of the locking hook.偏心套 ΔL represents the force attenuation caused by stress relaxation of the eccentric sleeve. 碟簧 Let ΔL be the deformation of the disc spring. 锁钩 Let △L be the deformation of the lock hook. 偏心套 This represents the deformation of the eccentric sleeve.

[0080] The deformation caused by the tension attenuation of the spatial docking locking system can be expressed as:

[0081] △L 碟簧 =△L 锁钩 +△L 偏心套 +△L 壳体 (5)；

[0082] Where: △L 壳体 This represents the deformation of the shell.

[0083] By combining the force balance equation and the deformation equation, a tension attenuation model for the space docking locking system after a long service life can be established, namely, a simplified module for tension attenuation of the space docking locking system:

[0084]

[0085] The above formula is the first rule. Based on the first rule, a simplified tension attenuation module for spatial docking locking systems can be constructed, where △F 单套对接锁 K represents the tension attenuation of the space docking locking system. 锁钩 K is the equivalent stiffness of the locking hook. 偏心套 For the equivalent stiffness of the eccentric sleeve, △FR 碟簧 K represents the force reduction caused by stress relaxation of the disc spring. 碟簧 For the equivalent stiffness of the disc spring, △FR 锁钩 △FR is the force attenuation caused by the stress relaxation of the locking hook. 偏心套 ΔL represents the force attenuation caused by stress relaxation of the eccentric sleeve. 壳体 This represents the deformation of the shell.

[0086] To predict the stress relaxation of a single docking lock during service using a tension attenuation simplification module, it is necessary to determine the equivalent stiffness K of the lock hook. 锁钩 The equivalent stiffness K of the eccentric sleeve 偏心套 The force reduction ΔFR caused by stress relaxation of the disc spring 碟簧 The equivalent stiffness K of the disc spring 碟簧 The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 Deformation of the shell ΔL 壳体 There are 7 physical quantities.

[0087] Another step is to set the initial tension P, expected life, and N different test temperatures for the tension decay test of the space docking locking system. The N test temperatures are all greater than room temperature, and N≥2. At each test temperature, a rated load is continuously applied for a certain period of time. At each temperature, the tension decay amount ΔP of each tension decay deformable body is measured at time points t after a predetermined period of time. The rated load is the load that maintains the initial tension P.

[0088] Specifically as follows:

[0089] The initial tension was set to 37 kN, the expected lifespan was 15 years, and N different temperatures were set at 85℃, 115℃, 145℃ and 175℃. The tension decay of each tension decay deformation body was measured and recorded every 5 hours at each temperature.

[0090] Another step is to obtain the attenuation rate B at the engineering temperature and the attenuation rate A over 1 hour at the engineering temperature by using curve fitting and linear fitting based on the time points t and tension attenuation at multiple different test temperatures.

[0091] Another step is to construct a tension attenuation value module for the tension attenuation deformable body under the expected working life at the engineering temperature, based on the attenuation rate B and the 1-hour attenuation rate A at the engineering temperature, which is embedded with the second rule; another step is to input the expected life into the respective tension attenuation value modules of the disc spring, eccentric sleeve, and locking hook to obtain the force attenuation △FR caused by stress relaxation of the disc spring. 碟簧 The force reduction ΔFR caused by stress relaxation of the eccentric sleeve 偏心套 The force attenuation ΔFR caused by the stress relaxation of the locking hook 锁钩 .

[0092] Specifically as follows:

[0093] The force attenuation caused by stress relaxation in a disc spring can be determined according to the Arrhenius formula.

[0094]

[0095] In the formula V s As an index of the performance degradation of the test specimen, it can represent the rate of relaxation of the tension in the spatial docking system. In this invention, it is the stress relaxation rate at the engineering temperature, 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.

[0096] Taking the logarithm of both sides of the above equation, we get:

[0097] lnV s=lnγ-Q / kT (8);

[0098] That is, lnV s It exhibits a linear relationship with 1 / T. The lnV values ​​from experimental data at different temperatures are shown. s By performing curve fitting on ~1 / T, the stress relaxation rate V of the disc spring at the engineering temperature can be obtained. s Through V s Based on the definition, a linear fitting formula for the tension attenuation can be established as follows:

[0099] ΔP = A + Blnt, B = V S (9);

[0100] The above formula is the second rule. Based on the second rule, a module can be constructed that embeds the second rule, representing the tension decay value of a tension-decaying deformable body including a locking hook, disc spring, eccentric sleeve, and shell, during its expected working life at engineering temperatures. Here, ΔP is the tension decay amount, A is the decay rate over 1 hour at engineering temperatures, B is the decay rate at engineering temperatures, t is time, and V... s The stress relaxation rate is the stress relaxation rate at the engineering temperature.

[0101] Stress relaxation tests were conducted on the space docking interlocking system at 85℃, 115℃, 145℃, and 175℃ respectively. The load P-t curves at 85℃, 115℃, 145℃, and 175℃ can then be obtained from these stress relaxation tests. Figure 2 As shown, the ΔP-lnt curves at different temperatures are plotted respectively. Figure 3-6 As shown. For each Figure 3-6 The fitting equations and coefficients obtained from linear fitting are shown in Table 1.

[0102] Table 1: Fitting equations for stress relaxation of disc springs

[0103]

[0104] After obtaining Table 1, lnV can be plotted. s ~1 / T curve as shown Figure 7 As shown, the equation of the line is derived as follows:

[0105]

[0106] The stress relaxation rate at room temperature (298K) is derived, and substituting it into the above equation yields:

[0107]

[0108] To calculate A in the linear fitting formula, we can let t = 1h and use the definition of Vs:

[0109]

[0110] Taking the logarithm of both sides yields:

[0111] lnA=a / T+b (13);

[0112] In other words, lnA and 1 / T have a linear relationship. Similarly, linear fitting interpolation is used to calculate the coefficient of A at room temperature. The 1-hour disc spring tension attenuation rate is summarized in Table 2, and the lnA~1 / T curve is plotted. Figure 8 As shown.

[0113] Table 2: Disc Spring Tension Decay Rate at t=1h

[0114]

[0115] right Figure 8 The equation of the straight line obtained after fitting the image is:

[0116]

[0117] The calculation showed that A = 0.1352 at room temperature (T = 298 K). Both A and B at room temperature were input into the disc spring force attenuation module to calculate the force attenuation ΔFR caused by stress relaxation of the disc spring. 碟簧 =3191.3101N.

[0118] The force attenuation of the eccentric sleeve and locking hook can be determined using the same method as for disc springs. Stress relaxation curves of titanium alloy TC4R and titanium alloy TB2 at four temperatures (85℃, 115℃, 145℃, and 175℃) are used to calculate the force attenuation of the eccentric sleeve and locking hook. The force attenuation ΔFR caused by the stress relaxation of the eccentric sleeve is then obtained. 偏心套 =3423.04N, the force reduction ΔFR caused by the stress relaxation of the locking hook. 锁钩 =3005.05N.

[0119] Another step is to obtain the equivalent stiffness K of the disc spring based on the rated load and the static stiffness of the disc spring, eccentric sleeve, and locking hook at the engineering temperature, as well as the initial tension deformation under the rated load. 弹簧 The equivalent stiffness K of the eccentric sleeve 偏心套 The equivalent stiffness K of the locking hook 锁钩 .

[0120] Specifically as follows:

[0121] When a disc spring experiences stress relaxation, only the stress decreases while the deformation remains unchanged. Therefore, the deformation can be calculated using the stress before stress relaxation and the stiffness at room temperature. A static stiffness test of the disc spring was conducted at room temperature. Tension was applied to the disc spring using a force loading mechanism, and the tension value F and the corresponding deformation Δl were recorded. An F-Δl curve was plotted, and the slope of the F-Δl curve obtained from the static stiffness test was fitted. The average value yielded a disc spring stiffness E of 20582 N / mm. The initial deformation of the disc spring can be calculated from the static stiffness as follows:

[0122] Δl=P0 / E=1.7977mm (15);

[0123] P0 is the unrelaxed tension value of the disc spring, which is 37kN. Therefore, the formula for calculating the equivalent stiffness is:

[0124]

[0125] The equivalent stiffness of the eccentric sleeve and locking hook can be determined using the same method as for disc springs. Static stiffness tests are conducted, and both are loaded using a loading mechanism to calculate the results.

[0126] K 偏心套 =506792 N / mm, K 锁钩 =44014.08 N / mm (17).

[0127] Another step is to obtain the deformation ΔL of the shell based on the Young's modulus of the shell material and the initial tension P. 壳体 The details are as follows:

[0128] Shell deformation ΔL 壳体 The stress relaxation of the shell was first calculated using a fitting method, and then the deformation ΔL of the shell was calculated. This was obtained through finite element analysis of the shell material (e.g., 7A04) based on tensile and creep test data. 壳体 =0.01314mm.

[0129] Another step is to input the required parameters for the space docking lock tension attenuation simplification module to obtain the tension attenuation value of the space docking lock under the expected lifetime. Specifically:

[0130] Substituting the data determined above into the space docking lock system tension attenuation simplification module, the calculation shows that under the conditions of initial tension of 37kN, room temperature of 25℃, service life of 15 years, docking lock tension attenuation value of 2.453kN, attenuation rate of 6.629%, remaining locking force of 34.547kN, and preset tension attenuation threshold of 30kN, it is determined that the service life of the space docking lock system meets the requirements.

[0131] It should be noted that the device for determining the tension attenuation of the docking system under the expected life of the present invention is designed to achieve all or part of the above method. Those skilled in the art can make adaptive changes to the system and the device constituting the system as the above method is adjusted. Therefore, various possible modifications to the device for determining the tension attenuation of the docking system under the expected life and the various parts constituting the device will not be described in detail.

[0132] Those skilled in the art will understand that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

Claims

1. A method for determining the tension decay of a docking locking system under expected lifespan, characterized in that, It includes the following steps: Step S100: The active locking hook, passive locking hook, disc spring, eccentric sleeve, and shell in the space docking system are defined as tension-attenuating deformable bodies. Based on the force relationship between these deformable bodies after docking, a simplified tension attenuation module for the space docking system with an embedded first rule is constructed. The equivalent stiffness of the tension attenuation module is equal to that of the locking hook. K 锁钩 Equivalent stiffness of eccentric sleeve K 偏心套 The stress relaxation of the disc spring leads to a decrease in force Δ FR 碟簧 Equivalent stiffness of disc springs K 碟簧 The force attenuation Δ caused by the stress relaxation of the locking hook FR 锁钩 The force attenuation Δ caused by stress relaxation of the eccentric sleeve FR 偏心套 and the deformation of the shell Δ L 壳体 Related; Step S200: Set the initial tension for the tension attenuation test of the space docking locking system. P The test conditions include the expected lifespan and N different test temperatures, all of which are greater than room temperature, and N ≥ 2. At each test temperature, a rated load is continuously applied for a certain duration. At each test temperature, the tension decay amount Δ of each tension decay deformable body is measured at time points t after a predetermined duration. P Wherein, the rated load is the load used to maintain the initial tension. P The load; Step S300: Based on the time points t and tension attenuation at the N different test temperatures obtained in step S200, the attenuation rate at the engineering temperature is obtained through curve fitting and linear fitting. B and the 1-hour decay rate at engineering temperature A ; Step S400: Based on the decay rate at the engineering temperature obtained in step S300 B and the 1-hour decay rate at engineering temperature A Construct a module for the tension decay value of the tension decay deformable body with embedded second rule at the expected working life at engineering temperature; Step S500: Input the expected lifespan into the respective tension attenuation value modules of the disc spring, eccentric sleeve, and locking hook constructed in step S400 to obtain the force attenuation Δ caused by stress relaxation of the disc spring. FR 碟簧 The force attenuation Δ caused by stress relaxation of the eccentric sleeve FR 偏心套 The force attenuation Δ caused by the stress relaxation of the locking hook FR 锁钩 ; Step S600: Obtain the equivalent stiffness of the disc spring based on the rated load and the static stiffness of the disc spring, eccentric sleeve, and locking hook at the engineering temperature, as well as the initial tension deformation under the rated load. K 碟簧 Equivalent stiffness of eccentric sleeve K 偏心套 The equivalent stiffness of the locking hook K 锁钩 ; Step S700: Based on the Young's modulus of the shell material and the initial tension P The deformation Δ of the shell is obtained. L 壳体 ; Step S800: Input the values obtained in steps S500 - S700 into the tension attenuation simplification module of the space docking latch system constructed in step S100 to obtain the tension attenuation amount of the space docking latch system under the expected life.

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

3. The method for determining the tension attenuation of a docking locking system under the expected lifespan according to claim 1, characterized in that, The initial tension described in step S200 is 37 kN, the expected life is 15 years, N different temperatures are 85°C, 115°C, 14°C, and 175°C respectively, and the tension attenuation amounts of each tension attenuation deformable body are measured and recorded every 5 hours at each temperature.

4. The method for determining the tension attenuation of a docking interlocking system under expected lifespan according to claim 1, characterized in that, Step S300 includes: Step S310: Based on the measurement time points t and tension decay Δ at N different test temperatures P A curve showing the relationship between tension decay and the logarithm of time was plotted. Based on the linear relationship between tension decay and the logarithm of time, the slope was fitted using the least squares method. This slope represents the decay rate at the test temperature. Vsn ; Step S320: Plot the relationship curve of attenuation rate - reciprocal of temperature at different test temperatures, and combine the linear relationship between the attenuation rate and the reciprocal of temperature to fit the slope of the attenuation rate and the reciprocal of temperature, and the slope of the attenuation rate and the reciprocal of temperature is the average attenuation rate. Step S330: Plot the logarithm of the average decay rate versus the reciprocal of temperature based on the average decay rate. Then, combining this with the linear relationship between the logarithm of the average decay rate and the reciprocal of temperature, use the least squares method to fit the linear relationship between the logarithm of the average decay rate and the reciprocal of temperature, and obtain the decay rate at the engineering temperature. B ; Step S340: Plot the logarithm of the 1-hour decay rate versus the reciprocal of temperature curve. Combine this with the linear relationship between the logarithm of the 1-hour decay rate and the reciprocal of temperature, and fit the curve to obtain the intercept of the 1-hour decay rate at the engineering temperature. A .

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

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

7. A device for determining the tension decay of a docking locking system under expected lifespan, characterized in that, The device includes: A simplified tension attenuation module for spatial docking locking systems, which incorporates a first rule, and the equivalent stiffness of the spatial docking locking system tension attenuation module and the locking hook. K 锁钩 Equivalent stiffness of eccentric sleeve K 偏心套 The force reduction Δ caused by stress relaxation of the disc spring FR 碟簧 Equivalent stiffness of disc springs K 碟簧 The force attenuation Δ caused by the stress relaxation of the locking hook FR 锁钩 The force attenuation Δ caused by stress relaxation of the eccentric sleeve FR 偏心套 and the deformation of the shell Δ L 壳体 Related; An initial data storage device is used to store the preset initial tension for the tension attenuation test of the space docking locking system. P The expected lifespan, time points t during the test, and the tension decay Δ of each tension decay deformable body measured at each time point. P The test is conducted at N different test temperatures, all of which are greater than room temperature, and N ≥ 2. At each test temperature, a rated load is continuously applied for a certain duration. At each test temperature, the tension decay amount Δ of each tension decay deformable body is measured at time points t after a predetermined duration. P Wherein, the rated load is the load used to maintain the initial tension. P The load; The first fitter is used to obtain the decay rate at the engineering temperature based on the time points t and tension decay amounts at N different test temperatures stored in the initial data storage device, through curve fitting and linear fitting. B and the 1-hour decay rate at engineering temperature A ; The module for tension decay values ​​during the expected operating life at engineering temperatures includes an embedded second rule, which, along with the decay rate obtained at engineering temperatures from the first fitter, is used to calculate the decay rate. B and the 1-hour decay rate at engineering temperature A related; The force attenuation calculation device is used to obtain the force attenuation Δ caused by stress relaxation of the disc spring through the tension attenuation value module during the expected operating life at engineering temperature. FR 碟簧 The force attenuation Δ caused by stress relaxation of the eccentric sleeve FR 偏心套 The force attenuation Δ caused by the stress relaxation of the locking hook FR 锁钩 ; The equivalent deformation coefficient calculation device is used to obtain the equivalent stiffness of the disc spring based on the rated load and the static stiffness of the disc spring, eccentric sleeve, and locking hook at the engineering temperature, as well as the initial tension deformation under the rated load. K 碟簧 Equivalent stiffness of eccentric sleeve K 偏心套 The equivalent stiffness of the locking hook K 锁钩 ; A shell deformation calculation device is used to calculate the deformation based on the Young's modulus of the shell material and the initial tension. P The deformation Δ of the shell is obtained. L 壳体 ; A space docking latch system tension attenuation calculation device, which is used to obtain the data obtained by the force attenuation calculation device, the equivalent deformation coefficient calculation device, and the housing deformation amount calculation device, and use the space docking latch system tension attenuation simplification module to obtain the tension attenuation amount of the space docking latch system under the expected life.

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

9. The device for determining the tension attenuation of a docking lock system under expected lifespan according to claim 7, characterized in that, The initial tension recorded by the initial data storage device is 37 kN, the expected life is 15 years, N different temperatures are 85°C, 115°C, 14°C, and 175°C respectively, and the tension attenuation amounts of each tension attenuation deformable body are measured and recorded every 5 hours at each temperature.

10. The device for determining the tension attenuation of a docking locking system under expected lifespan according to claim 7, characterized in that, The first fitting device includes: Temperature decay rate calculator, used to calculate the measurement time point t and tension decay amount Δ at N different test temperatures. P A curve showing the relationship between tension decay and the logarithm of time was plotted. Based on the linear relationship between tension decay and the logarithm of time, the slope was fitted using the least squares method. This slope represents the decay rate at the test temperature. Vsn ; An average attenuation rate calculator, which is used to plot the relationship curve of force attenuation rate - reciprocal of temperature at different test temperatures, and combine the linear relationship between the attenuation rate and the reciprocal of temperature to fit the slope of the attenuation rate and the reciprocal of temperature, and the slope of the attenuation rate and the reciprocal of temperature is the average attenuation rate. This engineering temperature decay rate calculator plots a curve showing the logarithm of the average decay rate versus the reciprocal of temperature. It then uses the least squares method to fit this linear relationship between the logarithm of the average decay rate and the reciprocal of temperature, ultimately obtaining the decay rate at the engineering temperature. B ; This calculator calculates the 1-hour decay rate at engineering temperatures. It plots the logarithm of the 1-hour decay rate against the reciprocal of temperature. By combining this with the linear relationship between the logarithm of the 1-hour decay rate and the reciprocal of temperature, the intercept obtained is the 1-hour decay rate at the engineering temperature. A .

11. The device for determining the tension attenuation of a docking locking system under expected lifespan according to claim 7, characterized in that, The second rule embedded is: △ P = A + B ln t, B = V s ； Where, Δ P This is the amount of tension attenuation. A The decay rate over 1 hour at the engineering temperature. B The decay rate is at the engineering temperature, and t is time. V s The stress relaxation rate is the stress relaxation rate at the engineering temperature.

12. The device for determining the tension attenuation of a space docking interlocking system under expected lifespan according to claim 7, characterized in that, It further includes a tension attenuation comparison device, which is used to compare the obtained tension attenuation amount of the space docking latch system under the expected life with the preset tension attenuation threshold. If the obtained tension attenuation amount of the space docking latch system under the expected life is not higher than the preset tension attenuation threshold, then output qualified.

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