A shear box and a testing device for simulating the ring shear test of lunar soil

Abstract

This application relates to the field of material testing, and specifically discloses a shear box and a testing device for simulating lunar soil ring shear testing. The shear box includes a lower box body, an upper box body, an axial loading assembly, a vacuum airway, and a shear seam adjustment mechanism; the testing device includes a ring shear tester and a shear box. Among them, the ring shear tester includes a torsional shear measurement and control module, an axial loading measurement and control module, and a sensing module. The sensing module includes a temperature sensing assembly, an acoustic emission sensor, etc. This application can provide a simulation of the lunar soil environment with multi-field coupling including vacuum, temperature, and mechanical loading, and realize the multi-field collaborative analysis and cross-scale research of the mechanical behavior of lunar soil.

Description

Technical Field

[0001] The present application relates to the field of material testing, and particularly to a shear box and a testing device for simulating lunar soil ring shear testing. Background Art

[0002] In recent years, with the advancement of the human deep space exploration program, the research on the lunar surface environment and the mechanical properties of its materials has gradually become one of the key topics in the field of aerospace science and engineering. As the main covering on the lunar surface, the mechanical properties of lunar soil not only directly affect the design and operation of lunar surface equipment, but also are related to the smooth implementation of planetary exploration missions and the planning and construction of lunar-based facilities. However, due to the special low-gravity, vacuum, and high temperature difference environment on the moon, the mechanical behavior and particle motion characteristics of lunar soil under different loading states are significantly different from those of terrestrial soil, and special research and testing methods are urgently needed to explore them.

[0003] Traditional soil mechanics testing equipment and methods are difficult to fully simulate the extreme lunar environment, and it is difficult to achieve high-precision tracking and analysis of the microscopic motion of soil particles during the testing process. In current research, many ring shear testing devices are only for conventional environments and do not effectively consider the influence of complex conditions such as lunar vacuum and temperature fluctuations. Summary of the Invention

[0004] In order to simulate the lunar environment and achieve comprehensive testing of the macroscopic mechanical behavior and particle microscopic motion characteristics of simulated lunar soil under various loading conditions, the present application provides a shear box and a testing device for simulating lunar soil ring shear testing.

[0005] The shear box for simulating lunar soil ring shear testing provided by the present application adopts the following technical solutions:

[0006] A shear box for simulating lunar soil ring shear testing, comprising:

[0007] A lower box body, fixedly arranged on the shear disc of the ring shear apparatus. The lower box body includes a coaxially fixedly connected lower box inner cylinder and a lower box outer cylinder. A ring-shaped space for accommodating the specimen is formed between the lower box inner cylinder and the lower box outer cylinder. A bottom plate in contact with the specimen is arranged at the bottom of the lower box body, and the bottom plate is made of a breathable material;

[0008] An upper box body, including a coaxially fixedly connected upper box inner cylinder and an upper box outer cylinder. The upper box body is rotatably arranged on the lower box body, and a shear gap is arranged between the two;

[0009] An axial loading assembly for applying axial pressure to the specimen, including a loading punch slidably arranged along the axis of the upper box body in the upper box body, and the loading punch is made of a breathable material;

[0010] The vacuum airway includes an upper air extraction channel and a lower air extraction channel. The upper air extraction channel is communicated with the loading ram, and the lower air extraction channel is communicated with the bottom plate. Both the upper air extraction channel and the lower air extraction channel are communicated with the external vacuum environment;

[0011] The shear seam adjusting mechanism is used to adjust the width of the shear seam.

[0012] During use, place the ring shear apparatus in the lunar surface environmental chamber (high and low temperature vacuum chamber) or industrial CT. Fill the shear box with simulated lunar soil samples, then fix the shear box on the shear disc of the ring shear apparatus, and use the axial loading component to apply axial pressure to the samples. The shear disc rotates to apply torque to the samples. The upper air extraction channel and the lower air extraction channel communicate the samples with the external vacuum environment, making the samples in the simulated lunar vacuum environment.

[0013] Further, the breathable material is breathable sintered brass.

[0014] Further, the lower box body further includes a base, the bottom plate is fixedly arranged on the upper end surface of the base, and the lower air extraction channel is arranged through the base.

[0015] Further, the axial loading component further includes a plurality of connecting rods fixedly connected to the loading ram, and the upper air extraction channel is arranged through the connecting rods.

[0016] This application realizes sufficient gas exchange in the upper and lower directions of the samples, not only improves the vacuum pumping efficiency, but also ensures the uniformity of the pumping process, providing reliable support for simulating the lunar surface environment.

[0017] Further, both the inner cylinder of the lower box and the inner cylinder of the upper box are provided with inner ventilation channels. One end of the inner ventilation channel is in contact with the sample and the other end is communicated with the external vacuum environment.

[0018] The inner ventilation channel directly connects the inside of the sample to the external vacuum environment, which can not only improve the efficiency of vacuum pumping, but also help to maintain the uniformity of the vacuum inside the sample.

[0019] Further, a filtering structure is arranged at one end of the inner ventilation channel in contact with the sample.

[0020] The filtering structure helps to prevent the sample from entering the inner ventilation channel during the vacuum pumping process.

[0021] Further, the shear gap adjusting mechanism includes a shear gap adjusting ring rotatably arranged on the shear disc. The shear gap adjusting ring is sleeved outside the outer cylinder of the lower box. The upper end surface of the shear gap adjusting ring is provided with a plurality of inclined surfaces at intervals. The inclination direction of the inclined surfaces extends along the circumferential direction of the shear gap adjusting ring. A plurality of bumps corresponding to the inclined surfaces one by one are fixedly arranged on the outer peripheral side of the outer cylinder of the upper box. Each bump abuts against the corresponding inclined surface.

[0022] Further, a plurality of nuts are fixedly arranged on the outer peripheral side of the outer cylinder of the upper box. Each nut is threadedly connected with an adjusting bolt. The adjusting bolt is vertically arranged and its bottom end abuts against the upper end surface of the shear disc.

[0023] When adjusting the width of the shear gap, first loosen the adjusting bolt so that its bottom end no longer abuts against the shear disc. Then rotate the shear gap adjusting ring. During this process, the inclined surface abuts against the bump, pushing the outer cylinder of the upper box upward or causing the outer cylinder of the upper box to move downward under its own gravity, thereby adjusting the distance between the outer cylinder of the upper box and the outer cylinder of the lower box, that is, realizing the adjustment of the shear gap width. After adjustment, tighten the adjusting bolt so that its bottom end abuts against the shear disc to lock the shear gap width. The width of the shear gap can be calculated from the rotation angle of the shear gap adjusting ring and the inclination angle of the inclined surface.

[0024] By precisely adjusting the width of the shear gap, the width of the shear gap is adapted to the particle gradation and force requirements of the lunar soil, ensuring that the shear process is closer to the actual lunar surface force conditions, specifically including:

[0025] When testing the simulated lunar soil in a loose state, the contact force between particles is easily affected by external interference. By setting an adjustable shear gap, the uniformity of the force on the simulated lunar soil during shear can be adjusted, avoiding the extrusion or crushing of particles due to too small a shear gap, or uneven stress concentration due to too large a gap.

[0026] During the shear process, the simulated lunar soil particle soil mass exhibits complex particle sliding, rolling and rearrangement behaviors. The adjustment of the shear gap can help control the spatial limitations of these behaviors, thus more realistically reflecting the deformation characteristics of the particle soil mass under shear action. For example, by moderately increasing the shear gap, the particle sliding and interface friction phenomena of the particle soil mass can be better observed.

[0027] This application also provides a test device for simulating lunar soil ring shear test, including a ring shear apparatus and a shear box. The shear box includes the aforementioned shear box for simulating lunar soil ring shear test. The ring shear apparatus includes:

[0028] A torsional shear measurement and control module for applying torque to the specimen and collecting stress data;

[0029] Axial loading measurement and control module, used to apply axial pressure to the specimen and collect stress data;

[0030] Sensing module, including a temperature sensor for measuring the temperature of the specimen, an acoustic emission sensor for monitoring the internal structure change of the specimen, and an LVDT sensor for measuring the axial deformation of the specimen.

[0031] Furthermore, the shear box further includes a shear box for simulating the ring shear CT test of lunar soil.

[0032] When the ring shear apparatus is placed in the lunar surface environmental chamber (high and low temperature vacuum chamber), a shear box for simulating the ring shear test of lunar soil is used to conduct macroscopic shear tests. When the ring shear apparatus is placed inside the industrial CT equipment, a shear box for simulating the ring shear CT test of lunar soil is used. Through the dynamic observation of the movement trajectories of soil particles under various stress states such as shear and compression by the industrial CT equipment, the coupling mechanism between the macro and micro mechanical behaviors of the simulated lunar soil can be revealed.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] 1. The present application can provide a simulation of the lunar soil environment with multi-field coupling including vacuum, temperature, and mechanical loading, realize the multi-field collaborative analysis of the mechanical behavior of lunar soil, and ensure the authenticity and reliability of the test results; by using the shear loading device and the industrial CT to work together, through multi-field coupling tests, the cross-scale mechanical properties are deeply analyzed, and the macro stress state is organically combined with the microscopic movement characteristics of particles to reveal the macro-micro mechanical coupling mechanism of lunar soil.

[0035] 2. The use of the air extraction channel in cooperation with the sintered brass material with excellent air permeability forms an air flow penetrating the specimen, realizing sufficient gas exchange in the upper and lower directions of the specimen, not only improving the vacuum pumping efficiency but also ensuring the uniformity of the pumping process, providing reliable support for simulating the lunar surface environment;

[0036] 3. The shear gap adjustment ring is used to quickly and accurately adjust the width of the shear gap, making the width of the shear gap adapt to the particle gradation and stress requirements of lunar soil, ensuring that the shear process is closer to the actual lunar surface stress conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the overall structural schematic diagram of a shear box for simulating the ring shear test of lunar soil in Embodiment 1 of the present application;

[0038] Figure 2 is the overall structural schematic diagram of another angle of a shear box for simulating the ring shear test of lunar soil in Embodiment 1 of the present application;

[0039] Figure 3It is a schematic cross-sectional structure diagram of a shear box for simulating lunar soil ring shear test in Embodiment 1 of the present application;

[0040] Figure 4 It is a schematic cross-sectional view mainly for showing the vacuum air duct and air flow direction in a shear box for simulating lunar soil ring shear test in Embodiment 1 of the present application;

[0041] Figure 5 It is a schematic cross-sectional structure diagram of a shear box for simulating lunar soil ring shear CT test in Embodiment 2 of the present application;

[0042] Figure 6 It is a schematic overall structure diagram of a test device for simulating lunar soil ring shear test in Embodiment 3 of the present application;

[0043] Figure 7 It is a schematic cross-sectional structure diagram of a test device for simulating lunar soil ring shear test in Embodiment 3 of the present application.

[0044] Reference signs: 1, lower box body; 11, base; 12, inner lower box cylinder; 121, first inner ventilation hole channel; 122, axial hole channel; 13, outer lower box cylinder; 14, bottom plate; 15, lower air extraction hole channel; 2, upper box body; 21, top plate; 22, inner upper box cylinder; 221, second inner ventilation hole channel; 23, outer upper box cylinder; 24, convex block; 25, nut; 26, adjusting bolt; 3, axial loading assembly; 31, loading press head; 32, connecting rod; 33, pressing plate; 34, upper air extraction hole channel; 4, shear gap adjusting ring; 41, inclined surface; 5, shear gap; 6, shear disc; 7, specimen; 8, ring shear apparatus; 81, torsional shear measurement and control module; 82, axial loading measurement and control module; 83, reaction frame; 84, LVDT sensor; 85, shear box placement cabin; 86, acoustic emission sensor; 87, temperature sensor. Detailed implementation manners

[0045] The following further Figure 1-7 describes the present application in detail.

[0046] Embodiment 1

[0047] Embodiment 1 of the present application discloses a shear box for simulating lunar soil ring shear test. Referring to Figure 1 、 Figure 2 and Figure 3 , the shear box for simulating lunar soil ring shear test includes a lower box body 1, an upper box body 2, an axial loading assembly 3, a vacuum duct and a shear gap adjusting mechanism. Among them, the lower box body 1 is fixedly arranged on the shear disc 6 of the ring shear apparatus. During the shear test, the upper box body 2 remains stationary, and the lower box body 1 rotates with the shear disc 6. The materials of the lower box body 1 and the upper box body 2 are aviation aluminum.

[0048] Referring to Figure 3 andFigure 4 , the lower box body 1 includes a lower box inner cylinder 12, a lower box outer cylinder 13, a bottom plate 14 and a base 11. The lower box inner cylinder 12 is fixedly connected to the base 11 by screws, the lower box outer cylinder 13 is fixedly connected to the base 11 through a slot structure, and the bottom plate 14 is fixedly arranged on the base 11. The lower box inner cylinder 12 and the lower box outer cylinder 13 are coaxially arranged, and an annular space for accommodating the simulated lunar soil sample 7 is formed therebetween. A toothed or striped anti-slip structure is provided on the surface of the bottom plate 14 in contact with the sample 7 to prevent relative sliding between the sample 7 and the bottom plate 14 during the torsional shear process.

[0049] Refer to Figure 3 and Figure 4 , the upper box body 2 includes an upper box inner cylinder 22, an upper box outer cylinder 23 and a top plate 21. Both the upper box inner cylinder 22 and the upper box outer cylinder 23 are fixedly connected to the top plate 21 by screws. The upper box inner cylinder 22 and the upper box outer cylinder 23 are coaxially arranged, and an annular space for accommodating the simulated lunar soil sample 7 is formed therebetween. The inner diameter of the lower box outer cylinder 13 is the same as the inner diameter of the upper box outer cylinder 23, and the outer diameter of the lower box outer cylinder 13 is smaller than the outer diameter of the upper box outer cylinder 23.

[0050] Refer to Figure 3 and Figure 4 , the upper box inner cylinder 22 is sleeved outside the lower box inner cylinder 12 and the two are rotatably connected, so that the upper box body 2 is rotatably arranged on the lower box body 1. A gap is provided between the upper box outer cylinder 23 and the lower box outer cylinder 13, and this gap is the shear gap 5. The shear gap adjusting mechanism is used to adjust the width of the shear gap 5.

[0051] Refer to Figure 1 , Figure 2 and Figure 3 , the axial loading assembly 3 includes a loading ram 31, a connecting rod 32 and a pressing plate 33. The loading ram 31 is slidably arranged along the axis of the upper box body 2 in the upper box body 2 for applying axial pressure to the sample 7; the pressing plate 33 is located outside the upper box body 2 and is connected to the axial loading device of the ring shear apparatus. A plurality of connecting rods 32 are provided, and the plurality of connecting rods 32 penetrate through the top plate 21 and are connected between the loading ram 31 and the pressing plate 33.

[0052] Both the bottom plate 14 and the loading ram 31 are made of breathable sintered brass. Refer to Figure 4 , the vacuum airway includes an upper air extraction channel 34 and a lower air extraction channel 15. The upper air extraction channel 34 is penetrated through the connecting rod 32 and communicated with the loading ram 31, the lower air extraction channel 15 is penetrated through the base 11 and communicated with the bottom plate 14, and both the upper air extraction channel 34 and the lower air extraction channel 15 are communicated with the external vacuum environment.

[0053] Refer to Figure 4, both the lower box inner cylinder 12 and the upper box inner cylinder 22 are provided with internal ventilation channels. Specifically, the lower box inner cylinder 12 is axially provided with an axial channel 122 communicating with the external vacuum environment along its own axis, and the lower box inner cylinder 12 is radially provided with a first internal ventilation channel 121. One end of the first internal ventilation channel 121 is in contact with the specimen 7, and the other end is communicated with the axial channel 122. The upper box inner cylinder 22 is provided with a second internal ventilation channel 221. One end of the second internal ventilation channel 221 is in contact with the specimen 7, and the other end penetrates through the top plate 21 and communicates with the external vacuum environment.

[0054] During use, the ring shear apparatus is placed in a lunar surface environmental chamber (high and low temperature vacuum chamber) or an industrial CT. The shear box is filled with a simulated lunar soil specimen 7, and then the base 11 of the shear box is fixed on the shear disc 6 of the ring shear apparatus. The axial loading assembly 3 is used to apply an axial pressure to the specimen 7, and the shear disc 6 rotates to apply a torque to the specimen 7. The upper air extraction channel 34 and the lower air extraction channel 15 communicate the specimen 7 with the external vacuum environment, so that the specimen 7 is in a vacuum environment simulating the lunar surface.

[0055] Figure 4 The arrows in show the gas flow path during vacuum pumping. The present application realizes sufficient gas exchange in the upper and lower directions of the specimen 7, not only improving the vacuum pumping efficiency, but also ensuring the uniformity of the pumping process, providing reliable support for simulating the lunar surface environment. The internal ventilation channel directly connects the inside of the specimen 7 to the external vacuum environment, which can not only improve the vacuum pumping efficiency, but also help maintain the uniformity of the vacuum inside the specimen 7. In order to prevent the specimen 7 from entering the internal ventilation channel during vacuum pumping, a filtering structure is provided at one end of the internal ventilation channel in contact with the specimen 7. The filtering structure can adopt multiple layers of filter meshes or breathable sintered brass.

[0056] In order to adapt the width of the shear seam 5 to the lunar soil particle gradation and the force requirement, and ensure that the shear process is closer to the actual lunar surface force condition, the present application adopts a shear seam adjusting mechanism to precisely adjust the width of the shear seam 5. Refer to Figure 1 , Figure 2 and Figure 3 , the shear seam adjusting mechanism includes a shear seam adjusting ring 4 rotatably arranged on the shear disc 6, and the shear seam adjusting ring 4 is sleeved outside the lower box outer cylinder 13. Refer to Figure 1 and Figure 2 , multiple inclined surfaces 41 are spaced on the upper end surface of the shear seam adjusting ring 4, and the inclination direction of the inclined surfaces 41 extends along the circumferential direction of the shear seam adjusting ring 4; multiple protrusions 24 corresponding to the inclined surfaces 41 one by one are fixedly arranged on the outer peripheral side of the upper box outer cylinder 23, and each protrusion 24 abuts against the corresponding inclined surface 41.

[0057] Further, refer to Figure 1 and Figure 2, a plurality of nuts 25 are fixedly arranged on the outer peripheral side of the upper box outer cylinder 23, and each nut 25 is threadedly connected with an adjusting bolt 26. The adjusting bolt 26 is vertically arranged and its bottom end abuts against the upper end surface of the shear disc 6.

[0058] When adjusting the width of the shear slot 5, first loosen the adjusting bolt 26 so that its bottom end no longer abuts against the shear disc 6; then rotate the shear slot adjusting ring 4. During this process, the inclined surface 41 abuts against the convex block 24, jacking up the upper box outer cylinder 23 or causing the upper box outer cylinder 23 to move downward under its own gravity, thereby adjusting the distance between the upper box outer cylinder 23 and the lower box outer cylinder 13, that is, realizing the adjustment of the width of the shear slot 5. After the adjustment is in place, tighten the adjusting bolt 26 so that its bottom end abuts against the shear disc 6 to lock the width of the shear slot 5. The width of the shear slot 5 can be calculated from the rotation angle of the shear slot adjusting ring 4 and the inclination angle of the inclined surface 41.

[0059] Embodiment 2

[0060] This application embodiment discloses a shear box for simulating lunar soil ring shear CT tests. Refer to Figure 5 , the shear box for simulating lunar soil ring shear CT tests includes a lower box body 1 and a loading platen 31. Among them, the lower box body 1 is fixedly arranged on the shear disc 6 of the ring shear apparatus. During the shear test, the loading platen 31 remains stationary while the lower box body 1 rotates with the shear disc 6.

[0061] Refer to Figure 5 , the lower box body 1 includes a lower box inner cylinder 12, a lower box outer cylinder 13, a bottom plate 14 and a base 11. The lower box inner cylinder 12 is fixedly connected to the base 11 by screws, the lower box outer cylinder 13 is fixedly connected to the base 11 through a slot structure, and the bottom plate 14 is fixedly connected to the lower box inner cylinder 12. The lower box inner cylinder 12 and the lower box outer cylinder 13 are coaxially arranged, and a ring-shaped space for accommodating the simulated lunar soil specimen 7 is formed between them. A toothed or striped anti-slip structure is arranged on the surface of the bottom plate 14 in contact with the specimen 7 to prevent relative sliding between the specimen 7 and the bottom plate 14 during the torsional shear process. The bottom plate 14 is made of breathable sintered brass.

[0062] The lower box outer cylinder 13 is made of transparent PEEK material, or other transparent plastics can also be used, which is convenient for observing the shear surface of the specimen 7.

[0063] The loading platen 31 is used to apply an axial pressure to the specimen 7, and its shape is adapted to the ring-shaped space in the lower box body 1. The loading platen 31 is provided with a cavity along its own axis for installing a temperature sensor 87.

[0064] To simulate the lunar surface vacuum environment, evacuation channels can be drilled through the base 11 and the inner cylinder 12 of the lower box. One end of the evacuation channel is connected to the bottom plate 14, and the other end is connected to the external vacuum environment. Additionally, an evacuation channel can be drilled through the loading indenter 31. One end of the evacuation channel is connected to the specimen 7, and the other end is connected to the external vacuum environment.

[0065] Embodiment 3

[0066] An embodiment of the present application discloses a test device for simulating lunar soil ring shear tests. Referring to Figure 6 and Figure 7 , the test device includes a ring shear apparatus 8 and a shear box. The shear box includes a shear box for simulating lunar soil ring shear tests disclosed in Embodiment 1 or a shear box for simulating lunar soil CT ring shear tests disclosed in Embodiment 2. The ring shear apparatus 8 includes a torsional shear measurement and control module 81, an axial loading measurement and control module 82, and a sensing module. The ring shear apparatus 8 further includes a shear box placement chamber 85 for placing the shear box.

[0067] The torsional shear measurement and control module 81 includes a shear disc and a motor for driving the shear disc to rotate. The base of the shear box is fixed to the shear disc. During the test, a torque is applied to the specimen by rotating the shear disc, and at the same time, the torsional shear measurement and control module 81 collects stress data.

[0068] The axial loading measurement and control module 82 includes a reaction frame 83, whose output end is connected to the axial loading assembly of the shear box, for applying an axial pressure to the specimen and collecting stress data.

[0069] The sensing module includes a temperature sensor 87 for measuring the temperature of the specimen, an acoustic emission sensor 86 for monitoring changes in the internal structure of the specimen, and an LVDT sensor 84 for measuring the axial deformation of the specimen. Among them, the acoustic emission sensor 86 is installed in the shear box placement chamber 85 and is located above the shear box. When using the shear box for simulating lunar soil ring shear tests disclosed in Embodiment 1, as Figure 3 shown, the temperature sensor 87 can be installed in the axial channel of the inner cylinder 12 of the lower box. When using the shear box for simulating lunar soil CT ring shear tests disclosed in Embodiment 2, as Figure 5 shown, the temperature sensor 87 can be installed in the axial cavity of the loading indenter 31.

[0070] Embodiment 4

[0071] An embodiment of the present application discloses a method for simulating lunar soil ring shear tests considering the lunar surface environment. Using the test device for simulating lunar soil ring shear tests disclosed in Embodiment 3 and the shear box for simulating lunar soil ring shear tests disclosed in Embodiment 1, the test method includes the following steps:

[0072] Step 1, assemble the shear box: Install the shear box on the shear disc 6.

[0073] Step 2, filling the specimen: Load the simulated lunar soil specimen into the shear box.

[0074] Step 3, adjusting the width of the shear gap: Rotate the shear gap adjustment ring 4 to make the shear gap 5 reach the set width, and tighten the adjustment bolt 26 to fix the width of the shear gap 5.

[0075] Step 4, preparing the test device: Install the reaction frame 83 and the axial loading measurement and control module 82; install the LVDT sensor 84; control the axial loading measurement and control module 82 to make the loading indenter 31 contact the top of the specimen 7.

[0076] Step 5, connection and environment setting: Place the test device in the lunar surface environment chamber, and connect the test device to the computer control system through the aviation plug adapter of the lunar surface environment chamber; adjust the vacuum degree, temperature and other parameters of the lunar surface environment chamber to the required test conditions.

[0077] Step 6, setting the loading and collecting data: Set the test loading steps on the computer side, apply axial force and torque to the specimen 7 respectively through the axial loading measurement and control module 82 and the torsional shear measurement and control module 81, and collect the stress and strain data during the test; the acoustic emission sensor 86 records the amplitude-frequency characteristic curve, and the temperature sensor 87 collects the temperature data near the specimen 7.

[0078] This method can repeat the mechanical test procedures of cyclic loading and unloading, and study the residual deformation and particle movement characteristics of lunar soil under multiple loading conditions. A dynamic loading device can also be introduced to simulate the mechanical disturbances caused by the operation of lunar equipment or meteorite impacts through high-frequency vibration or impact methods. Torque and axial force can also be applied synchronously to study the inter-particle friction and force chain distribution of lunar soil under complex loading conditions.

[0079] In the test, particles of various particle sizes, morphologies and materials can be mixed to simulate lunar soil, and the influence of its particle gradation on the macroscopic mechanical properties can be studied. A micron-level coating can be applied to the surface of the simulated lunar soil particles to simulate the real physical and chemical properties of lunar soil particles, and the applicability of the experimental results can be enhanced. A small amount of liquid can also be introduced between the particles to simulate the possible ice-water effect in the lunar polar regions, and the influence of it on the mechanical properties of the soil can be studied.

[0080] Example 5

[0081] This application example discloses an in-situ CT simulation lunar soil mechanical test method, which uses a test device for simulating lunar soil ring shear test disclosed in Example 3, and the shear box uses a shear box for simulating lunar soil ring shear CT test disclosed in Example 2. The test method includes the following steps:

[0082] Step 1, assembling the shear box: Install the shear box onto the shear disc 6.

[0083] Step 2, filling the specimen: Load the simulated lunar soil specimen into the shear box.

[0084] Step 3, preparing the test device: Install the reaction frame 83 and the axial loading measurement and control module 82; install the LVDT sensor 84; control the axial loading measurement and control module 82 to make the loading indenter 31 contact the top of the specimen 7.

[0085] Step 4, placing the industrial CT system: Place the entire test device on the rotary table inside the industrial CT scanner; adjust the height of the radiation source to accurately align it with the specimen 7 in the transparent shear box.

[0086] Step 5, loading and data acquisition: Set the loading steps on the computer side, apply axial force and torque to the specimen 7 through the axial loading measurement and control module 82 and the torsional shear measurement and control module 81 respectively, and collect stress and strain data during the test; the acoustic emission sensor 86 records the amplitude-frequency characteristic curve, and the temperature sensor 87 collects the temperature data near the specimen 7.

[0087] Step 6, microscopic imaging and analysis: Pause the loading when the test reaches the preset data acquisition state point; start the industrial CT rotary table to drive the test device to rotate synchronously, scan and image the specimen 7, and obtain the microscopic change data under the loaded state.

[0088] This method can cooperate with a multi-angle CT scanning device to perform 360° observation on lunar soil samples, improving the reconstruction accuracy of particle movement trajectories. High-speed scanning technology can be introduced to capture the movement state of particles in real time during the shear process, adapting to the research on particle behavior under high-speed loading or vibration shear conditions. It can also combine image processing and artificial intelligence technologies to identify particle boundaries and shapes through CT images, quantify particle deformation and its movement trajectories, and enhance the data post-processing ability.

[0089] It should be noted that the test device and test method provided in this application can not only be used for the mechanical property test of simulated lunar soil, but also be applied to the simulation and mechanical property test of soils on planets or satellites such as Mars and Europa. By appropriately modifying the test device to adapt to the deep-sea high-pressure and low-temperature environment, it can also be used to study the movement characteristics of deep-sea soil particles.

[0090] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A shear box for simulating the ring shear test of lunar regolith, characterized in that: Comprising: A lower box body, fixedly arranged on the shearing disc of the ring shear apparatus. The lower box body includes a coaxially fixedly connected lower box inner cylinder and a lower box outer cylinder. An annular space for accommodating the specimen is formed between the lower box inner cylinder and the lower box outer cylinder. A bottom plate in contact with the specimen is arranged at the bottom of the lower box body, and the bottom plate is made of a breathable material. An upper box body, including a coaxially fixedly connected upper box inner cylinder and an upper box outer cylinder. The upper box body is rotatably arranged on the lower box body, and a shear gap is arranged between the two. An axial loading assembly, used to apply an axial pressure to the specimen, including a loading punch slidably arranged along the axial direction of the upper box body in the upper box body, and the loading punch is made of a breathable material. A vacuum airway, including an upper air extraction channel and a lower air extraction channel. The upper air extraction channel is communicated with the loading punch, the lower air extraction channel is communicated with the bottom plate, and both the upper air extraction channel and the lower air extraction channel are communicated with the external vacuum environment. A shear gap adjusting mechanism, used to adjust the width of the shear gap. The shear gap adjusting mechanism includes a shear gap adjusting ring rotatably arranged on the shearing disc. The shear gap adjusting ring is sleeved outside the lower box outer cylinder. A plurality of inclined surfaces are arranged at intervals on the upper end surface of the shear gap adjusting ring, and the inclination direction of the inclined surface extends along the circumferential direction of the shear gap adjusting ring. A plurality of bumps corresponding to the inclined surfaces one by one are fixedly arranged on the outer peripheral side of the upper box outer cylinder, and each bump abuts against the corresponding inclined surface.

2. The shear box for simulating lunar regolith ring shear test according to claim 1, characterized in that: The breathable material is breathable sintered brass.

3. A shear box for simulating lunar soil ring shear test according to claim 1, characterized in that: The lower box body further includes a base, the bottom plate is fixedly arranged on the upper end surface of the base, and the lower air extraction channel is arranged through the base.

4. A shear box for simulating lunar regolith ring shear test according to claim 1, characterized in that: The axial loading assembly further includes a plurality of connecting rods fixedly connected to the loading punch, and the upper air extraction channel is arranged through the connecting rods.

5. A shear box for simulating lunar soil ring shear test according to claim 1, characterized in that: Both the lower box inner cylinder and the upper box inner cylinder are provided with inner ventilation channels. One end of the inner ventilation channel is in contact with the specimen and the other end is communicated with the external vacuum environment.

6. A shear box for simulating lunar regolith ring shear test according to claim 5, characterized in that: A filtering structure is arranged at one end of the inner ventilation channel in contact with the specimen.

7. A shear box for simulating lunar regolith ring shear test according to claim 1, characterized in that: A plurality of nuts are fixedly arranged on the outer peripheral side of the upper box outer cylinder, and each nut is threadedly connected with an adjusting bolt. The adjusting bolt is arranged vertically and its bottom end abuts against the upper end surface of the shearing disc.

8. A test device for simulating the ring shear test of lunar soil, characterized in that: Including a ring shear apparatus and a shear box. The shear box includes a shear box for simulating lunar soil ring shear test according to any one of claims 1-7. The ring shear apparatus includes: A torsional shear measurement and control module, used to apply torque to the specimen and collect stress data. An axial loading measurement and control module, used to apply axial pressure to the specimen and collect stress data. A sensing module, including a temperature sensor for measuring the temperature of the specimen, an acoustic emission sensor for monitoring the internal structure change of the specimen, and an LVDT sensor for measuring the axial deformation of the specimen.

9. The test device for simulating lunar soil ring shear test according to claim 8, characterized in that: The shear box further includes a shear box for simulating lunar soil ring shear CT test.

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