A method for analyzing mechanical and stratification characteristics of lunar soil collection and shaping

Abstract

The present invention proposes a method for analyzing mechanical properties and bedding properties in a lunar soil collection and shaping process, which belongs to the technical field of lunar soil collection. Firstly, a lunar soil particle model is constructed based on a discrete element method to simulate the contact and collision behaviors between lunar soil particles, and to perform simulation design that meets the engineering size scale; a layered probability method is used to analyze the bedding retention characteristics of lunar soil samples under different working conditions; a relative displacement method is used to analyze and evaluate the bedding properties of the shaping process: by calculating the displacement of particles in the lunar soil sample relative to characteristic particles, a force analysis of a sampling bag in the shaping process under engineering size is performed: a force analysis of the cross section of the sampling bag is performed in different regions, and the oscillation form and peak value of the torque applied to the sampling bag under different working conditions are analyzed; the present invention can more accurately simulate and analyze the lunar soil sampling process, which helps to improve the quality of the collected lunar soil samples, thereby providing more reliable data support for the study of lunar geology, chemistry and physical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of lunar soil collection, and in particular, relates to a method for analyzing the mechanical properties and bedding properties of a lunar soil collection and shaping process. Background Art

[0002] In the lunar exploration project, collecting lunar soil and returning it is the core engineering issue of this phase of the mission. For the deep lunar soil sampling mission, since the lunar soil samples obtained have a certain depth, it is expected that the collected and returned lunar soil samples can maintain the lunar quality information of the in-situ lunar soil well on the basis of sufficient quantity. However, traditional lunar soil sampling technology often ignores the mechanical behavior and layer structure of lunar soil samples during collection, coring, shaping and transportation. These factors are crucial to the integrity of the samples and the accuracy of scientific research analysis. At the same time, lunar soil samples will be affected by various forces during the collection process, including gravity, friction and extrusion, which will affect the mechanical properties and layer structure of the samples. The destruction of the layer structure may lead to the loss of sample information and affect the accuracy of the research results.

[0003] The lunar soil samples in the coring soft bag are taken out of the coring tube along with the coring soft bag and transferred to the shaping mechanism for shaping, which involves the mechanical problems related to the soft bag and the lunar soil samples during the coring, shaping and sample transfer process. This includes the accumulation of lunar soil samples due to gravity during the coring process, the bending and deformation of the soft bag during the sample shaping process, and the squeezing effect on the internal lunar soil samples. Therefore, it is necessary to analyze the mechanical characteristics of coring shaping and sample transfer, study the migration behavior of lunar soil samples during the coring-shaping-transfer process, determine the key parameters in the coring-shaping-transfer process, and formulate coring and shaping procedures. Summary of the invention

[0004] In response to the shaping problem of deep lunar soil sampling, the present invention proposes a method for analyzing the mechanical properties and bedding properties of the lunar soil collection and shaping process, which can more accurately simulate and analyze the lunar soil sampling process, help improve the quality of lunar soil samples, and thus provide more reliable data support for the study of lunar geology, chemistry and physical properties.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for analyzing mechanical properties and bedding properties during lunar soil collection and shaping: the method specifically comprises the following steps:

[0007] Step 1: Establish a lunar soil particle contact and collision model: Based on the discrete element method, a lunar soil particle model is constructed to simulate the contact and collision behavior between lunar soil particles and conduct simulation design that meets the engineering scale;

[0008] Step 2: Analysis of bedding retention characteristics: Use the stratification probability method to analyze the bedding retention characteristics of lunar soil samples under different working conditions;

[0009] Step 3: Use the relative displacement method to analyze and evaluate the bedding characteristics of the shaping process: By calculating the displacement of particles in the lunar soil sample relative to the characteristic particles, the bedding retention characteristics under different working conditions are evaluated;

[0010] Step 4: Perform stress analysis on the sampling bag during the shaping process under engineering dimensions: perform stress analysis on the cross section of the sampling bag in different regions, and analyze the stress conditions of the sampling bag under different working conditions;

[0011] Step 5: Record the changes in the torque applied to the sampling bag during the simulation process; analyze the oscillation form and peak value of the torque applied to the sampling bag under different working conditions;

[0012] Step 6: Comprehensively analyze the bedding retention characteristics and force analysis results; obtain the bedding retention characteristics and force influence of the lunar soil collection and shaping process under different working conditions.

[0013] Furthermore, in step 1, the sample filling rate of the lunar soil, the winding radius of the sampling bag and the diameter of the sampling bag are considered in accordance with the engineering scale; in each simulation experiment, only one parameter is changed using the single variable method.

[0014] Furthermore, in step 2, different sample filling rates, sampling bag winding radii, and sampling bag diameters are set; the effects of various working conditions on the layer retention characteristics of lunar soil samples are analyzed;

[0015] The lunar soil sample filling rate is divided into three conditions: 75%, 90%, and 100%;

[0016] The sampling bag winding radius is divided into four working conditions: 65mm, 57mm, 40mm, and 30mm;

[0017] The sampling bag diameters are divided into four working conditions: 21mm, 18mm, 15mm, and 8mm.

[0018] Furthermore, in step 3, characteristic particles are selected, and the relative positions of each layer of particles with respect to the characteristic particles in the initial and final states are calculated. The relative positions at the two moments are subtracted to obtain the relative displacement of each layer of particles relative to the characteristic point, and the average value is taken to obtain the evaluation index of the relative displacement method.

[0019] Further, in step 4, the sampling bag is divided into zones, which are defined as: upper side, lower side, inner side and outer side;

[0020] The stress conditions of the sampling bag at different sample filling rates, sampling bag winding radii and sampling bag diameters were analyzed to evaluate the differences in stress at the bottom, middle, inside and outside.

[0021] Furthermore, in step 6, under any working condition, the force on the bottom of the sampling bag is greater than the force on the middle, and the force on the inner and outer sides is greater than the force on the upper and lower sides. For different filling rates, as the filling rate increases, the force on the sampling bag increases; for different winding radii of the sampling bag, as the winding radius decreases, the force on the sampling bag increases; for different sampling bag diameters, as the diameter increases, the force on the sampling bag increases.

[0022] A system for analyzing the mechanical and stratification characteristics of lunar soil collection and shaping:

[0023] The analysis system includes a simulation module, a bedding retention characteristic analysis module, a bedding characteristic analysis and evaluation module, a mechanical analysis module and a summary module;

[0024] The simulation module establishes a lunar soil particle contact and collision model: constructs a lunar soil particle model based on the discrete element method, simulates the contact and collision behavior between lunar soil particles, and performs simulation design that meets the engineering size scale;

[0025] The bedding retention characteristic analysis module uses a layered probability method to analyze the bedding retention characteristics of lunar soil samples under different working conditions;

[0026] The bedding characteristics analysis and evaluation module adopts the relative displacement method to analyze and evaluate the bedding characteristics of the shaping process: by calculating the displacement of particles in the lunar soil sample relative to the characteristic particles, the bedding retention characteristics under different working conditions are evaluated;

[0027] The mechanical analysis module: performs stress analysis of the sampling bag during the shaping process under engineering dimensions: performs regional stress analysis on the cross section of the sampling bag, and analyzes the stress conditions of the sampling bag under different working conditions;

[0028] Record the changes in the torque applied to the sampling bag during the simulation process; analyze the oscillation form and peak value of the torque applied to the sampling bag under different working conditions;

[0029] The summary module comprehensively analyzes the bedding retention characteristics and force analysis results; and obtains the bedding retention characteristics and force influence of the lunar soil collection and shaping process under different working conditions.

[0030] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0031] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are implemented.

[0032] Beneficial effects of the present invention

[0033] The present invention uses the discrete element method to simulate the contact and collision of lunar soil particles, providing a more accurate analysis of the mechanical properties of the lunar soil; compared with traditional methods, it can more realistically reflect the mechanical behavior of the lunar soil during the collection and shaping process.

[0034] The "stratification probability method" proposed in the present invention provides a new quantitative analysis method for evaluating the bedding retention characteristics of lunar soil samples. Compared with the traditional "overall description method", it can more carefully evaluate the changes in the bedding structure of lunar soil samples under different working conditions.

[0035] The present invention conducts a detailed analysis of the forces and moments of the sampling bag under different working conditions, takes into account the actual engineering sampling bag winding radius and sample length during simulation design, optimizes the model size and particle characteristics, makes the simulation results closer to practical applications, and improves the accuracy and reliability of the simulation.

[0036] The present invention can more accurately simulate and analyze the lunar soil sampling process, help improve the quality of lunar soil samples, and thus provide more reliable data support for the study of lunar geology, chemistry and physical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the core lifting and shaping movement of lunar soil.

[0038] Figure 2 Schematic diagram of core shaping and sample transfer.

[0039] Figure 3 These are the initial generation states of the model of the present invention, (a) is particle generation, and (b) is gravity deposition.

[0040] Figure 4 It is a schematic diagram of the "layered probability method" of the present invention.

[0041] Figure 5 The stratification situation at the end of simulation under different filling rates.

[0042] Figure 6 These are the stratification probability cloud maps of lunar soil samples under different filling rate conditions, where (a) is a filling rate of 75%, (b) is a filling rate of 90%, and (c) is a filling rate of 100%.

[0043] Figure 7 The stratification situation at the end of simulation under different winding radii.

[0044] Figure 8 The stratification probability cloud maps of lunar soil samples under different sampling bag winding radius conditions, where (a) is a winding radius of 30 mm, (b) is a winding radius of 40 mm, and (c) is a winding radius of 65 mm.

[0045] Fig. 9The stratification situation at the end of simulation under different sampling bag diameters.

[0046] Fig.10 The stratification probability cloud maps of lunar soil samples under different sampling bag diameters, where (a) is the sampling bag diameter of 8 mm, (b) is the sampling bag diameter of 15 mm, and (c) is the sampling bag diameter of 21 mm.

[0047] Fig.11 The relative displacement method of the present invention is used for stratification and characteristic particle selection.

[0048] Fig.12 The average relative displacement curves of lunar soil samples of each layer under 9 groups of working conditions of the present invention, where (a) is the relative displacement under different filling rates, (b) is the relative displacement under different sampling bag winding radii, and (c) is the relative displacement under different sampling bag diameters.

[0049] Fig.13 The present invention provides a stress analysis of the sampling bag in different regions.

[0050] Fig.14 The stress condition in the middle of the sampling bag when the filling rate is 75%, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0051] Fig.15 The stress condition at the bottom of the sampling bag when the filling rate is 75%, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0052] Fig.16 The stress condition in the middle of the sampling bag when the filling rate is 90%, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0053] Fig.17 The stress condition at the bottom of the sampling bag when the filling rate is 90%, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0054] Fig.18 The stress condition in the middle of the sampling bag when the filling rate is 100%, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0055] Fig.19 The stress condition at the bottom of the sampling bag when the filling rate is 100%, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0056] Fig. 20 The stress condition in the middle of the sampling bag under the condition of winding radius of 30 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0057] Fig.21 The force condition at the bottom of the sampling bag when the winding radius is 30 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0058] Fig. 22 The stress condition in the middle of the sampling bag under the condition of winding radius of 40 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0059] Fig.23 The force condition at the bottom of the sampling bag under the condition of winding radius of 40 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0060] Fig.24 The stress condition in the middle of the sampling bag under the condition of winding radius of 65 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0061] Fig.25 The force condition at the bottom of the sampling bag under the condition of winding radius of 65 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0062] Fig.26 The stress condition in the middle of the sampling bag when the diameter of the sampling bag is 8 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0063] Fig. 27 The force condition at the bottom of the sampling bag when the diameter of the sampling bag is 8 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0064] Fig.28 The stress condition in the middle of the sampling bag when the diameter of the sampling bag is 15 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0065] Fig.29 The force condition at the bottom of the sampling bag when the diameter of the sampling bag is 15 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0066] Fig.30 The stress condition in the middle of the sampling bag when the diameter of the sampling bag is 21 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0067] Fig.31 The force condition at the bottom of the sampling bag when the diameter of the sampling bag is 21 mm, where (a) is the upper side, (b) is the lower side, (c) is the inner side, and (d) is the outer side.

[0068] Fig.32 This is the moment analysis of the sampling bag, where (a) is the moment of the sampling bag at different filling rates, (b) is the moment of the sampling bag at different winding radii, and (c) is the moment of the sampling bag at different sampling bag diameters. DETAILED DESCRIPTION

[0069] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0071] The working process of the shaping mechanism is: to realize the shaping of the lunar soil soft coring bag through extraction and spiral winding movement, and to send the shaped lunar soil sample into the packaging device.

[0072] The specific implementation of the core lifting and shaping movement is as follows Figure 1 As shown, the primary packaging container can rotate under the drive of the mechanism, and the path guide device can move along the axial direction of the primary packaging container under the drive of the mechanism, and the core pull rope and the drilled sample enter the primary packaging container under the guidance of the path guide device. In the core pull rope winding stage (core lifting stage), the primary packaging container rotates, and the path guide device does not move, so that the core pull rope can be rotated in situ; in the drilled sample winding stage (sample shaping stage), the primary packaging container rotates, and the path guide device moves under the drive of the mechanism to realize the spiral winding shaping of the drilled sample.

[0073] After the primary packaging container completes sample shaping, it is necessary to separate the primary packaging container from the mechanism. When the guide cylinder and the packaging device are installed coaxially with a distance of 0.1 mm, the container slides into the packaging device along the guide cylinder under the action of 1 / 6 of the gravity on the lunar surface.

[0074] The present invention proposes a method for analyzing the mechanical properties and layering properties of lunar soil collection and shaping process:

[0075] Step 1: Establish a lunar soil particle contact and collision model;

[0076] A lunar soil particle model is constructed based on the discrete element method to simulate the contact and collision behavior between lunar soil particles. The model's microscopic parameters are optimized using the existing experimental data of real lunar soil, and simulation design is carried out to meet the engineering scale to ensure the accuracy of the model.

[0077] Through discrete element triaxial simulation tests, the corresponding mesoscopic parameters of the lunar soil discrete element model were optimized and designed, and finally the values ​​of each mesoscopic parameter were calibrated so that under this parameter setting, the macroscopic mechanical properties of the lunar soil discrete element model meet the macroscopic mechanical properties of the real lunar soil.

[0078] The lunar soil discrete element model in the deep sampling process is different from the lunar soil discrete element model in the discrete element triaxial simulation test in terms of gravity environment and size design. In order to simulate the real deep sampling process, the gravity environment needs to be set to the lunar gravity environment G = 1.67m / s 2 .

[0079] The simulation design of the whole process of deep sampling is divided into the drilling process of the drill tool and the core lifting and shaping process of the sampling bag. For the drilling process of the drill tool, the designed drilling amount is 114mm, the feed speed is 0.01m / s, and the rotation speed of the drill tool is 4πrad / s. During the drilling process of the drill tool, the sampling bag is gradually generated with the feeding process of the drill tool, and the lower edge of the sampling bag is always kept parallel to the lower edge of the drill rod, so as to simulate the bag turning process of the sampling bag in the real drilling process. The final length of the sampling bag is the same as the drilling depth, both of which are 114mm. The sampling bag needs to be lifted in the z direction first. This is because the sampling bag and the lunar soil sample are still in the drill rod after the drilling is completed, and the lifting motion planning needs to be performed before the subsequent motion operations can be performed. After the lifting action is completed, the sampling bag needs to move obliquely upward, and finally move to the entrance of the sampler. A rotation transition is added to the lifting and oblique upward movements. After the oblique upward movement is completed, a short horizontal movement is also required, and a rotation transition is also required between the two. After horizontal movement, the sampling bag enters the sampler, performs spiral feeding movement, and is wound into a cylindrical tube shape.

[0080] The present invention is particularly aimed at simulation design of engineering scale. Taking into account the actual winding radius of the sampling bag in the project, the length of the lunar soil sample model should meet the circumference length of the winding radius to achieve a complete cycle of winding simulation. However, considering the impact of the model size on the calculation time, the length of the lunar soil sample model will not completely meet the length of a complete circle under limited computing power. A modeling method that reaches more than 3 / 4 of the circumference can be considered to meet the simulation requirements. Based on the above principles, a lunar soil sample model is established, and its size parameters are shown in Table 1. The initial generation state of the model is shown in Table 1. Figure 3 (a) shown.

[0081] Table 1 Size parameters and particle characteristics of lunar soil discrete element model

[0082]

[0083] The lunar soil sample model is initially generated as a cuboid with a 21mm×21mm square bottom and a model height of 500mm (the length after deposition meets the simulation requirements). After gravity deposition, the final height is maintained at 324mm, which can complete the winding simulation task of 3 / 4 of the circumference. Since it is necessary to observe the layering retention characteristics of the model, the model is layered and colored, with a total of 12 layers, each with a height of 27mm. For working conditions with different sampling bag diameters, the method of deleting particles is used to trim the bottom surface into a circular surface with diameters corresponding to the sampling bag diameter values ​​of the corresponding working conditions, such as Figure 3 (b) as shown.

[0084] The influence analysis of the parameters of lunar soil sample bedding retention characteristics during the shaping process under engineering size mainly focuses on three groups of influencing factors: sample filling rate, sampling bag winding radius, and sampling bag diameter. During the engineering test, it was found that the filling rate of the sampling bag was 90% in many cases, so three different simulation conditions were set around the filling rate value: lunar soil filling rate: 100%, 90%, and 75%. The winding radius of the sampling bag under engineering size is within the range of 57mm, so four different simulation conditions were set around the winding radius value: sampling bag winding radius: 30mm, 40mm, 57mm, and 65mm. On the one hand, the sampling bag diameter directly determines the size of the sampling volume, and on the other hand, it also has an impact on the winding process. Therefore, the influence of different sampling bag diameters on the bedding retention characteristics was analyzed under the engineering size model, and four different simulation conditions were set as sampling bag diameters: 8mm, 15mm, 18mm, and 21mm. The parameter settings of each group of conditions are shown in Table 2.

[0085] Table 2 Shaping process parameter design

[0086]

[0087] Step 2: Analysis of bedding retention characteristics: Use the stratification probability method to analyze the bedding retention characteristics of lunar soil samples under different working conditions; set different sample filling rates, sampling bag winding radii and diameter conditions; analyze the impact of each working condition on the bedding retention characteristics of lunar soil samples.

[0088] For situations like lunar soil samples where there is overall large-scale movement, the traditional bedding preservation evaluation method "overall description method" is not applicable. The present invention adopts a new bedding evaluation method-"stratification probability method", which uses probability statistics to perform stratification processing on the in-situ lunar soil and lunar soil samples with the same number of layers before and after sampling, and then counts the proportion of each layer of in-situ lunar soil in each layer of the lunar soil sample after sampling. By obtaining two-dimensional data on the proportion of each layer of in-situ lunar soil in each layer of lunar soil sample, the quality of the bedding preservation characteristics is evaluated. Ideally, each layer of the lunar soil sample should contain 100% of the same number of in-situ lunar soil layers. In reality, it is impossible to achieve 100% bedding preservation, but each layer of the lunar soil sample should contain the highest proportion of the same number of in-situ lunar soil layers, such as Figure 4 Shown

[0089] (2.1) Sample filling rate

[0090] In actual projects, the sample filling rate is usually 90%, so the design filling rate is 75%, 90%, and 100% to analyze the effect of the sample filling rate on the bedding retention characteristics. Figure 5 The following table shows the stratification of samples under three conditions at the end of the simulation. It can be seen that the first layer of lunar soil samples has the greatest impact under different sample filling rates, while the other layers have little impact. Figure 6 It can also be seen that: with the increase of sample filling rate, the bedding characteristics of the first layer of lunar soil samples gradually improve, but the bedding characteristics of other layers of lunar soil samples do not change significantly.

[0091] Table 3 Delamination probability of lunar soil samples under the condition of 75% filling rate

[0092]

[0093] Table 4 Delamination probability of lunar soil samples under the condition of 90% filling rate

[0094]

[0095]

[0096] Table 5 Lunar soil sample stratification probability values ​​under the filling rate 100% condition

[0097]

[0098] (2.2) Sampling bag winding radius

[0099] In actual projects, the winding radius of the sampling bag is more common at 57mm. Therefore, the winding radius of the sampling bag is designed to be 65mm, 57mm, 40mm, and 30mm. The influence of the winding radius of the sampling bag on the bedding retention characteristics is analyzed. Figure 7The following table shows the delamination of the samples under four working conditions at the end of the simulation. Figure 8 It can be seen that: as the winding radius of the sampling bag decreases, the stratification probability value of each layer of lunar soil samples decreases and the stratification characteristics deteriorate.

[0100] Table 6 Delamination probability of lunar soil samples under winding radius of 30 mm

[0101]

[0102] Table 7 Delamination probability of lunar soil samples under winding radius of 40 mm

[0103]

[0104] Table 8 Delamination probability of lunar soil samples under winding radius of 65 mm

[0105]

[0106]

[0107] (2.3) Sampling bag diameter

[0108] In actual projects, the diameter of the sampling bag is more common at 18mm, so the sampling bag winding radius is designed to be 21mm, 18mm, 15mm, and 8mm. The influence of the sampling bag diameter on the bedding retention characteristics is analyzed. Fig. 9 The following table shows the delamination of the samples under four working conditions at the end of the simulation. Fig.10 It can be seen that: with the increase of the diameter of the sampling bag, the stratification probability value of each layer of lunar soil samples decreases and the stratification characteristics deteriorate.

[0109] Table 9 Stratification probability of lunar soil samples under the condition of sampling bag diameter 8mm

[0110]

[0111] Table 10 Lunar soil sample stratification probability values ​​under the condition of sampling bag diameter 15 mm

[0112]

[0113] Table 11 Lunar soil sample stratification probability values ​​under the condition of sampling bag diameter 21mm

[0114]

[0115]

[0116] Step 3: Analysis of bedding characteristics during shaping (relative displacement method evaluation): The relative displacement method is used to evaluate the bedding retention characteristics under different working conditions by calculating the displacement of particles in the lunar soil sample relative to the characteristic particles.

[0117] The relative displacement method is derived from the traditional bedding preservation evaluation method "overall description method". It records the particle positions in the initial and final states, and stratifies the lunar soil samples in the initial state. A characteristic particle is selected in each layer. Each layer of samples is based on the characteristic particles of this layer. The relative displacement of the particles relative to the set characteristic particles is calculated, and the average relative displacement of the particles in each layer is used as the evaluation index. The schematic diagram of the method is shown in the figure. Fig.11 As shown:

[0118] The relative position of each layer of particles with respect to the characteristic particles in the initial and final states is calculated. The relative position at the two moments is subtracted to obtain the relative displacement of each layer of particles relative to the characteristic point. The average value is then taken to obtain the evaluation index of the relative displacement method. Fig.12 The figure shows the average relative displacement curves of lunar soil samples of each layer under 9 working conditions. It can be seen that: for different filling rates, except for the first layer of lunar soil samples, there is no obvious change in other layers of samples, and the larger the filling rate, the smaller the relative displacement; for different winding radii, the change of winding radius affects the number of winding circles, the smaller the radius, the more circles, and the more extreme values ​​of relative displacement appear. The overall trend is that the smaller the winding radius, the greater the relative displacement; for different sampling bag diameters, all layers of lunar soil are affected, and the larger the sampling bag diameter, the greater the relative displacement. The above analysis conclusions are consistent with the conclusions obtained by the stratified probability method.

[0119] For the analysis of the bedding retention characteristics of the shaping process under engineering dimensions, we focus on the influence of three main parameters: sample filling rate, sampling bag winding radius, and sampling bag diameter. The "stratified probability method" is used to analyze the bedding retention characteristics of each layer of lunar soil under different working parameters. The simulation results show that different sample filling rates only affect the first layer of lunar soil samples, and the larger the sample filling rate, the better the bedding retention characteristics. Changes in the sampling bag winding radius have an impact on all layers of lunar soil samples. The smaller the winding radius, the worse the bedding retention characteristics. Changes in the sampling bag diameter have an impact on all layers of lunar soil samples. The larger the diameter, the worse the bedding retention characteristics.

[0120] Analyzing the reasons for the above phenomenon, under different sample filling rates, the boundary surface of the first layer of lunar soil cannot be maintained due to movement and gravity, and the "dumping" phenomenon will naturally occur. When the sample filling rate is smaller, the "dumping" phenomenon is more thorough, and the bedding retention characteristics of the first layer of lunar soil will deteriorate. The smaller the winding radius of the sampling bag, the greater the bending deformation inside and outside, which will lead to the deterioration of the bedding retention characteristics of the lunar soil samples. The larger the diameter of the sampling bag, the greater the compression of the inner lunar soil sample and the stretching of the outer lunar soil sample under the same bending deformation, and the bedding retention characteristics will also deteriorate. At the same time, the relative displacement method is used to analyze the bedding retention characteristics of the lunar soil samples, and the conclusions obtained are consistent with the stratification probability method.

[0121] Step 4: Stress analysis of sampling bag during shaping process (engineering dimensions): Stress analysis of sampling bag: Stress analysis of the sampling bag cross section is performed in different regions to analyze the stress conditions under different filling rates, winding radii and diameters;

[0122] like Fig.13 As shown, the cross-section of the sampling bag is analyzed for stress conditions in different regions. Since the sampling bag performs a spiral feed motion along the +x direction and the center of rotation is located at a point on the -y axis, the sampling bag is divided into zones, which are defined as: upper side, lower side, inner side, and outer side.

[0123] (4.1) Sample filling rate

[0124] from Figures 14 to 19 It can be seen that under the same working conditions, the force on the bottom of the sampling bag is greater than that on the middle, and the force on the inside and outside of the sampling bag at the same position is greater than that on the upper and lower sides. As for the force conditions of the sampling bag under different working conditions, as the sample filling rate increases, the force conditions at each position increase.

[0125] (4.2) Sampling bag winding radius

[0126] from Figures 20 to 25 It can be seen that under the same working conditions, the force on the bottom of the sampling bag is greater than that on the middle, and the force on the inside and outside of the sampling bag at the same position is greater than that on the upper and lower sides. As for the force on the sampling bag under different working conditions, as the winding radius of the sample sampling bag decreases, the force on each position increases.

[0127] (4.3) Sampling bag diameter

[0128] from Figures 26 to 31 It can be seen that under the same working conditions, the force on the bottom of the sampling bag is greater than that in the middle, and the force on the inside and outside of the sampling bag at the same position is greater than that on the upper and lower sides. As for the force conditions of the sampling bag under different working conditions, as the diameter of the sample sampling bag increases, the force conditions at each position increase.

[0129] Step 5: Record the changes in the torque applied to the sampling bag during the simulation process; analyze the oscillation form and peak value of the torque applied to the sampling bag under different working conditions;

[0130] Record the changes in the torque of the sampling bag during the simulation process, and compare and analyze the 9 groups of working conditions to obtain Fig.32 From the comparison change curves shown, it can be seen that: for different filling rates, the oscillation form of the torque value applied to the sampling bag is different, and the smaller the filling rate, the larger the vibration peak; for different winding radii, the torque value applied to the sampling bag changes, and the larger the winding radius, the greater the torque applied; for different sampling bag diameters, the torque value applied to the sampling bag also changes, and the larger the diameter of the sampling bag, the greater the torque applied.

[0131] Step 6: Comprehensively analyze the bedding retention characteristics and stress analysis results;

[0132] For the shaping process under engineering size, the stress of the sampling bag is also concerned. First, the sampling bag interface is divided into regions, and the stress of different regions is analyzed. The simulation results show that under any working condition, the force on the bottom of the sampling bag is greater than the force on the middle, and the force on the inner and outer sides is greater than the force on the upper and lower sides. For different filling rates, the force on the sampling bag increases with the increase of the filling rate; for different sampling bag winding radii, the force on the sampling bag increases with the decrease of the winding radius; for different sampling bag diameters, the force on the sampling bag increases with the increase of the diameter. At the same time, the change of the torque on the sampling bag during the simulation process is recorded. For different filling rates, the oscillation form of the torque value on the sampling bag is different, and the smaller the filling rate, the larger the vibration peak; for different winding radii, the torque value on the sampling bag changes, and the larger the winding radius, the greater the torque; for different sampling bag diameters, the torque value on the sampling bag also changes, and the larger the diameter of the sampling bag, the greater the torque.

[0133] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0134] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are implemented.

[0135] The memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory read only memory, ROM, a programmable read-only memory programmable ROM, PROM, an erasable programmable read-only memory erasable PROM, EPROM, an electrically erasable programmable read-only memory electrically EPROM, EEPROM or flash memory. The volatile memory may be a random access memory random access memory, RAM, which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory static RAM, SRAM, dynamic random access memory dynamic RAM, DRAM, synchronous dynamic random access memory synchronous DRAM, SDRAM, double data rate synchronous dynamic random access memory double data rate SDRAM, DDR SDRAM, enhanced synchronous dynamic random access memory enhanced SDRAM, ESDRAM, synchronous link dynamic random access memory synchlink DRAM, SLDRAM and direct memory bus random access memory directrambus RAM, DRRAM. It should be noted that memory of the methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0136] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center through a wired method such as coaxial cable, optical fiber, digital subscriber line digital subscriber line, DSL or wireless such as infrared, wireless, microwave, etc. to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium such as a floppy disk, a hard disk, a tape, an optical medium such as a high-density digital video disc digital video disc, DVD, or a semiconductor medium such as a solid state hard disk solid state disc, SSD, etc.

[0137] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software modules in a processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0138] It should be noted that the processor in the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, a digital signal processor DSP, an application-specific integrated circuit ASIC, a field programmable gate array FPGA or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined to perform. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0139] The above is a detailed introduction to the mechanical properties and bedding properties analysis method of the lunar soil collection and shaping process proposed in the present invention, and the principles and implementation methods of the present invention are explained. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in the field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for analyzing the mechanical properties and bedding properties of lunar soil during its collection and shaping process, characterized in that: The method specifically comprises the following steps: Step 1: Establish a lunar soil particle contact and collision model: Based on the discrete element method, a lunar soil particle model is constructed to simulate the contact and collision behavior between lunar soil particles and conduct simulation design that meets the engineering scale; Step 2: Analysis of bedding retention characteristics: Use the stratification probability method to analyze the bedding retention characteristics of lunar soil samples under different working conditions; Step 3: Use the relative displacement method to analyze and evaluate the bedding characteristics of the shaping process: By calculating the displacement of particles in the lunar soil sample relative to the characteristic particles, the bedding retention characteristics under different working conditions are evaluated; Step 4: Perform stress analysis on the sampling bag during the shaping process under engineering dimensions: perform stress analysis on the cross section of the sampling bag in different regions, and analyze the stress conditions of the sampling bag under different working conditions; In step 4, the sampling bag is divided into zones, which are defined as: upper side, lower side, inner side and outer side; The stress conditions of the sampling bag under different sample filling ratios, sampling bag winding radii and sampling bag diameters were analyzed to evaluate the differences in stress at the bottom, middle, inner side and outer side. Step 5: Record the changes in the torque applied to the sampling bag during the simulation process; analyze the oscillation form and peak value of the torque applied to the sampling bag under different working conditions; Step 6: Comprehensively analyze the bedding retention characteristics and force analysis results; obtain the bedding retention characteristics and force influence of the lunar soil collection and shaping process under different working conditions; In step 6, under any working condition, the force on the bottom of the sampling bag is greater than the force in the middle, and the force on the inner and outer sides is greater than the force on the upper and lower sides; for different filling rates, the force on the sampling bag increases with the increase of the filling rate; for different winding radii of the sampling bag, the force on the sampling bag increases with the decrease of the winding radius; for different sampling bag diameters, the force on the sampling bag increases with the increase of the diameter.

2. The analysis method according to claim 1, characterized in that: In step 1, the sample filling rate of the lunar soil, the winding radius of the sampling bag, and the diameter of the sampling bag are considered in accordance with the engineering scale; in each simulation experiment, only one parameter is changed using the single variable method.

3. The analysis method according to claim 2, characterized in that: In step 2, different sample filling rates, sampling bag winding radii, and sampling bag diameters are set; the effects of various working conditions on the layer retention characteristics of lunar soil samples are analyzed; The lunar soil sample filling rate is divided into three conditions: 75%, 90%, and 100%; The sampling bag winding radius is divided into four working conditions: 65mm, 57mm, 40mm, and 30mm; The sampling bag diameters are divided into four working conditions: 21mm, 18mm, 15mm, and 8mm.

4. The analysis method according to claim 3, characterized in that: In step 3, characteristic particles are selected, and the relative positions of each layer of particles with respect to the characteristic particles in the initial and final states are calculated. The relative positions at the two moments are subtracted to obtain the relative displacement of each layer of particles relative to the characteristic point, and the average value is taken to obtain the evaluation index of the relative displacement method.

5. An analysis system for executing the method for analyzing mechanical properties and layering properties of the lunar soil collection and shaping process as described in any one of claims 1 to 4, characterized in that: The analysis system includes a simulation module, a bedding retention characteristic analysis module, a bedding characteristic analysis and evaluation module, a mechanical analysis module and a summary module; The simulation module establishes a lunar soil particle contact and collision model: constructs a lunar soil particle model based on the discrete element method, simulates the contact and collision behavior between lunar soil particles, and performs simulation design that meets the engineering size scale; The bedding retention characteristic analysis module uses a layered probability method to analyze the bedding retention characteristics of lunar soil samples under different working conditions; The bedding characteristics analysis and evaluation module adopts the relative displacement method to analyze and evaluate the bedding characteristics of the shaping process: by calculating the displacement of particles in the lunar soil sample relative to the characteristic particles, the bedding retention characteristics under different working conditions are evaluated; The mechanical analysis module: performs stress analysis of the sampling bag during the shaping process under engineering dimensions: performs regional stress analysis on the cross section of the sampling bag, and analyzes the stress conditions of the sampling bag under different working conditions; Record the changes in the torque applied to the sampling bag during the simulation process; analyze the oscillation form and peak value of the torque applied to the sampling bag under different working conditions; The summary module comprehensively analyzes the bedding retention characteristics and force analysis results; and obtains the bedding retention characteristics and force influence of the lunar soil collection and shaping process under different working conditions.

6. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium for storing computer instructions, characterized in that: When the computer instructions are executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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