Shearing box for simulating lunar soil ring shear test and testing device

Abstract

The invention relates to the field of material testing, and particularly discloses a shear box for simulating lunar soil ring shear testing and a testing device.The shear box comprises a lower box body, an upper box body, an axial loading assembly, a vacuum air channel and a shear seam adjusting mechanism; the testing device comprises a ring shear apparatus and a shear box, the ring shear apparatus comprises a torsional shear measurement and control module, an axial loading measurement and control module and a sensing module, and the sensing module comprises a temperature sensing assembly, an acoustic emission sensor and the like. According to the invention, multi-field coupled lunar soil environment simulation including vacuum, temperature, mechanical loading and the like can be provided, and multi-field collaborative analysis and cross-scale research of lunar soil mechanical behaviors are realized.

Description

Technical Field

[0001] The present application relates to the field of material testing, and in particular 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 human deep space exploration programs, the study of 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 of the lunar surface, the mechanical properties of lunar soil not only directly affect the design and operation of lunar 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 of the moon, the mechanical behavior and particle motion characteristics of lunar soil under different loading conditions are significantly different from those of earth 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 environment on the lunar surface, and it is difficult to achieve high-precision tracking and analysis of the microscopic movement of soil particles during the test. In current research, many ring shear test devices are only designed for conventional environments and fail to effectively consider the impact of complex conditions such as lunar vacuum and temperature fluctuations. Summary of the invention

[0004] In order to simulate the lunar surface environment and realize 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 ring shear testing of simulated lunar soil.

[0005] The shear box provided in this application for simulating lunar soil ring shear testing adopts the following technical solution: A shear box for simulating lunar soil ring shear testing, comprising: The lower box body is fixedly arranged on the shearing disk of the ring shear instrument, and the lower box body comprises a lower box inner cylinder and a lower box outer cylinder which are coaxially fixed, and an annular space for accommodating the sample is formed between the lower box inner cylinder and the lower box outer cylinder; a bottom plate in contact with the sample is arranged at the bottom of the lower box body, and the bottom plate is made of a breathable material; The upper box body comprises an upper box inner cylinder and an upper box outer cylinder which are coaxially fixed; the upper box body is rotatably arranged on the lower box body, and a gap arranged between the two is a shear gap; An axial loading assembly, used for applying axial pressure to the sample, comprising a loading pressure head slidably disposed in the upper box body along the axial direction of the upper box body, wherein the loading pressure head is made of a breathable material; A vacuum air channel, comprising an upper air pumping channel and a lower air pumping channel, wherein the upper air pumping channel is connected to the loading pressure head, and the lower air pumping channel is connected to the bottom plate, and both the upper air pumping channel and the lower air pumping channel are connected to an external vacuum environment; The shearing seam adjusting mechanism is used to adjust the width of the shearing seam.

[0006] When in use, the ring shear instrument is placed in a lunar environment box (high and low temperature vacuum chamber) or industrial CT, the simulated lunar soil sample is filled in the shear box, and then the shear box is fixed on the shear disk of the ring shear instrument. The axial loading assembly is used to apply axial pressure to the sample, and the shear disk rotates to apply torque to the sample. The upper and lower air extraction holes connect the sample with the external vacuum environment, so that the sample is in a vacuum environment simulating the lunar surface.

[0007] Furthermore, the air permeable material is air permeable sintered brass.

[0008] Furthermore, the lower box body also 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.

[0009] Furthermore, the axial loading assembly also includes a plurality of connecting rods fixedly connected to the loading pressure head, and the upper air extraction channel is arranged through the connecting rods.

[0010] This application achieves sufficient gas exchange in the upper and lower directions of the sample, which 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.

[0011] Furthermore, the lower box inner tube and the upper box inner tube are both provided with an inner ventilation channel, one end of the inner ventilation channel is in contact with the sample, and the other end is connected to the external vacuum environment.

[0012] The internal ventilation channel directly connects the interior of the sample to the external vacuum environment, which not only improves the efficiency of vacuum extraction, but also helps to maintain the uniformity of the vacuum inside the sample.

[0013] Furthermore, a filtering structure is provided at one end of the inner ventilation channel that contacts the sample.

[0014] The filter structure helps to prevent the sample from entering the internal ventilation channel during the vacuum process.

[0015] Furthermore, the shear seam adjustment mechanism includes a shear seam adjustment ring rotatably arranged on the shear disk, the shear seam adjustment ring is sleeved on the outside of the lower box outer tube, the upper end surface of the shear seam adjustment ring is provided with a plurality of inclined surfaces at intervals, and the inclination direction of the inclined surfaces extends along the circumferential direction of the shear seam adjustment ring; a plurality of protrusions corresponding to the inclined surfaces are fixedly provided on the outer peripheral side of the upper box outer tube, and each of the protrusions abuts against the corresponding inclined surface.

[0016] Furthermore, a plurality of nuts are fixedly provided on the outer circumference of the upper box outer cylinder, each of the nuts is threadedly connected with an adjusting bolt, and the adjusting bolt is vertically arranged and its bottom end abuts against the upper end surface of the shear disk.

[0017] When adjusting the width of the shearing seam, first loosen the adjusting bolt so that its bottom end no longer abuts against the shearing disk; then rotate the shearing seam adjusting ring. During this process, the inclined surface abuts against the protrusion, and the upper box outer cylinder is lifted upward or the upper box outer cylinder moves downward under its own gravity, thereby adjusting the distance between the upper box outer cylinder and the lower box outer cylinder, that is, adjusting the width of the shearing seam. After the adjustment is in place, tighten the adjusting bolt so that its bottom end abuts against the shearing disk to lock the width of the shearing seam. The width of the shearing seam can be calculated from the rotation angle of the shearing seam adjusting ring and the inclination angle of the inclined surface.

[0018] By precisely adjusting the width of the shear seam, the width of the shear seam is adapted to the lunar soil particle distribution and force requirements, ensuring that the shearing process is closer to the actual lunar surface force conditions, including: When testing the simulated lunar soil in a loose state, the contact force between particles is easily disturbed by the outside world. By setting an adjustable shear gap, the uniformity of the force on the simulated lunar soil during the shear process can be adjusted to avoid particles being squeezed or crushed due to a small shear gap, or uneven stress concentration due to a large gap.

[0019] During the shear process, the simulated lunar soil particles exhibit complex particle sliding, rolling and rearrangement behaviors. The adjustment of shear joints can help control the spatial limitations of these behaviors, thereby more realistically reflecting the deformation characteristics of the granular soil under shear. For example, by appropriately increasing the shear joints, the particle sliding and interface friction phenomena of the granular soil can be better observed.

[0020] The present application also provides a test device for simulating lunar soil ring shear test, including a ring shear instrument and a shear box, the shear box including the aforementioned shear box for simulating lunar soil ring shear test, the ring shear instrument including: Torsion shear measurement and control module, used to apply torque to the specimen and collect stress data; Axial loading measurement and control module, used to apply axial pressure to the sample and collect stress data; The sensing module includes a temperature sensor for measuring the temperature of the sample, an acoustic emission sensor for monitoring the changes in the internal structure of the sample, and an LVDT sensor for measuring the axial deformation of the sample.

[0021] Furthermore, the shear box also includes a shear box for simulating lunar soil ring shear CT testing.

[0022] When the ring shear instrument is placed in a lunar environmental chamber (high and low temperature vacuum chamber), a shear box used to simulate lunar soil ring shear tests is used to conduct macro shear tests. When the ring shear instrument is placed in an industrial CT device, a shear box used to simulate lunar soil ring shear CT tests is used. Through the dynamic observation of the movement trajectory of soil particles under various stress states such as shear and compression by the industrial CT device, the coupling mechanism between the macro-micro mechanical behaviors of simulated lunar soil can be revealed.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. This application can provide a lunar soil environment simulation with multi-field coupling including vacuum, temperature and mechanical loading, realize multi-field collaborative analysis of lunar soil mechanical behavior, and ensure the authenticity and reliability of the test results; utilize the shear loading device to work in conjunction with the industrial CT, conduct in-depth analysis of cross-scale mechanical properties through multi-field coupling testing, organically combine the macroscopic stress state with the microscopic motion characteristics of the particles, and reveal the macro-micro mechanical coupling mechanism of the lunar soil.

[0024] 2. The use of exhaust channels and sintered brass materials with excellent air permeability forms an airflow that penetrates the sample, achieving sufficient gas exchange in both the upper and lower directions of the sample, which not only improves the vacuum exhaust efficiency, but also ensures the uniformity of the exhaust process, providing reliable support for simulating the lunar environment; 3. The shear seam adjustment ring can be used to quickly and accurately adjust the shear seam width, so that the shear seam width is adapted to the lunar soil particle grading and force requirements, ensuring that the shearing process is closer to the actual lunar surface force conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall structure of a shear box for simulating lunar soil ring shear testing in Example 1 of the present application; Figure 2 This is a schematic diagram of the overall structure of a shear box for simulating lunar soil ring shear testing from another angle in Example 1 of the present application; Figure 3 This is a schematic cross-sectional structure diagram of a shear box for simulating lunar soil ring shear testing in Example 1 of the present application; Figure 4 The embodiment 1 of the present application is mainly used to show a cross-sectional schematic diagram of a vacuum air passage and airflow direction in a shear box for simulating lunar soil ring shear test; Figure 5 This is a schematic cross-sectional structure diagram of a shear box for simulating lunar soil ring shear CT testing in Example 2 of the present application; Figure 6 This is a schematic diagram of the overall structure of a test device for simulating lunar soil ring shear testing in Example 3 of the present application; Figure 7It is a schematic diagram of the cross-sectional structure of a test device for simulating lunar soil ring shear testing in Example 3 of the present application.

[0026] Figure numerals: 1, lower box body; 11, base; 12, lower box inner tube; 121, first inner ventilation channel; 122, axial channel; 13, lower box outer tube; 14, bottom plate; 15, lower exhaust channel; 2, upper box body; 21, top plate; 22, upper box inner tube; 221, second inner ventilation channel; 23, upper box outer tube; 24, bump; 25, nut; 26, adjusting bolt; 3, axial loading assembly; 31, loading pressure head; 32, connecting rod; 33, pressure plate; 34, upper exhaust channel; 4, shear gap adjustment ring; 41, inclined surface; 5, shear gap; 6, shear disk; 7, specimen; 8, ring shear instrument; 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 DESCRIPTION

[0027] The following is combined with Figure 1-7 This application is described in further detail.

[0028] Example 1 The present application embodiment discloses a shear box for simulating lunar soil ring shear testing. Figure 1 , Figure 2 and Figure 3 The shear box used to simulate the lunar soil ring shear test includes a lower box body 1, an upper box body 2, an axial loading assembly 3, a vacuum channel and a shear gap adjustment mechanism. The lower box body 1 is fixedly arranged on the shear disk 6 of the ring shear instrument. During the shear test, the upper box body 2 remains stationary, and the lower box body 1 rotates with the shear disk 6. The material of the lower box body 1 and the upper box body 2 is aviation aluminum.

[0029] Reference Figure 3 and Figure 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 by 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 arranged on the surface of the bottom plate 14 that contacts the sample 7, so as to prevent the sample 7 and the bottom plate 14 from sliding relative to each other during the torsion shear process.

[0030] Reference Figure 3 and Figure 4The upper box body 2 includes an upper box inner tube 22, an upper box outer tube 23 and a top plate 21, and the upper box inner tube 22 and the upper box outer tube 23 are fixedly connected to the top plate 21 by screws. The upper box inner tube 22 and the upper box outer tube 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 tube 13 is the same as the inner diameter of the upper box outer tube 23, and the outer diameter of the lower box outer tube 13 is smaller than the outer diameter of the upper box outer tube 23.

[0031] Reference Figure 3 and Figure 4 The upper box inner cylinder 22 is sleeved on 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 the gap is a shear gap 5. The shear gap adjustment mechanism is used to adjust the width of the shear gap 5.

[0032] Reference Figure 1 , Figure 2 and Figure 3 The axial loading assembly 3 includes a loading head 31, a connecting rod 32 and a pressing plate 33. The loading head 31 is slidably disposed in the upper box body 2 along the axial direction, and is used to apply 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 instrument, and 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 head 31 and the pressing plate 33.

[0033] The bottom plate 14 and the loading pressure head 31 are both made of air-permeable sintered brass. Figure 4 The vacuum air passage includes an upper air pumping hole 34 and a lower air pumping hole 15. The upper air pumping hole 34 is arranged through the connecting rod 32 and is connected with the loading pressure head 31. The lower air pumping hole 15 is arranged through the base 11 and is connected with the bottom plate 14. Both the upper air pumping hole 34 and the lower air pumping hole 15 are connected with the external vacuum environment.

[0034] Reference Figure 4 The lower box inner tube 12 and the upper box inner tube 22 are both provided with inner ventilation channels. Specifically, the lower box inner tube 12 is provided with an axial channel 122 connected to the external vacuum environment along its own axial direction, and the lower box inner tube 12 is provided with a first inner ventilation channel 121 along its own radial direction. One end of the first inner ventilation channel 121 is in contact with the sample 7, and the other end is connected to the axial channel 122. The upper box inner tube 22 is provided with a second inner ventilation channel 221. One end of the second inner ventilation channel 221 is in contact with the sample 7, and the other end passes through the top plate 21 and is connected to the external vacuum environment.

[0035] When in use, the ring shear instrument is placed in a lunar environment box (high and low temperature vacuum chamber) or industrial CT, the simulated lunar soil sample 7 is filled in the shear box, and then the base 11 of the shear box is fixed to the shear disk 6 of the ring shear instrument, and the axial loading assembly 3 is used to apply axial pressure to the sample 7, and the shear disk 6 rotates to apply torque to the sample 7. The upper exhaust channel 34 and the lower exhaust channel 15 connect the sample 7 with the external vacuum environment, so that the sample 7 is in a vacuum environment simulating the lunar surface.

[0036] Figure 4 The arrows in the figure show the path of gas flow during vacuuming. The present application realizes sufficient gas exchange in the upper and lower directions of sample 7, which not only improves the vacuum pumping efficiency, but also ensures the uniformity of the pumping process, providing reliable support for simulating the lunar environment. The internal ventilation channel directly connects the interior of sample 7 to the external vacuum environment, which not only improves the efficiency of vacuuming, but also helps to maintain the uniformity of the vacuum inside sample 7. In order to prevent sample 7 from entering the internal ventilation channel during vacuuming, a filtering structure is provided at the end of the internal ventilation channel that contacts sample 7. The filtering structure can use a multi-layer filter screen or breathable sintered brass.

[0037] In order to make the width of the shear seam 5 adapt to the lunar soil particle grading and force requirements and ensure that the shearing process is closer to the actual lunar surface force conditions, the present application uses a shear seam adjustment mechanism to accurately adjust the width of the shear seam 5. Figure 1 , Figure 2 and Figure 3 The shear gap adjustment mechanism includes a shear gap adjustment ring 4 rotatably arranged on the shear disc 6, and the shear gap adjustment ring 4 is sleeved outside the lower box outer tube 13. Figure 1 and Figure 2 The upper end surface of the shear gap adjustment ring 4 is provided with a plurality of inclined surfaces 41 at intervals, and the inclination direction of the inclined surfaces 41 extends along the circumferential direction of the shear gap adjustment ring 4; a plurality of protrusions 24 corresponding to the inclined surfaces 41 are fixedly provided on the outer peripheral side of the upper box outer tube 23, and each protrusion 24 abuts against the corresponding inclined surface 41.

[0038] Further, refer to Figure 1 and Figure 2 A plurality of nuts 25 are fixedly disposed 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 disposed and its bottom end abuts against the upper end surface of the shear disk 6 .

[0039] When adjusting the width of the shearing seam 5, first loosen the adjusting bolt 26 so that its bottom end no longer abuts against the shearing disc 6; then rotate the shearing seam adjusting ring 4, during which the inclined surface 41 abuts against the protrusion 24, and the upper box outer cylinder 23 is lifted upward or the upper box outer cylinder 23 moves 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, adjusting the width of the shearing seam 5. After the adjustment is in place, tighten the adjusting bolt 26 so that its bottom end abuts against the shearing disc 6, and the width of the shearing seam 5 is locked. The width of the shearing seam 5 can be calculated by the rotation angle of the shearing seam adjusting ring 4 and the inclination angle of the inclined surface 41.

[0040] Example 2 The present application embodiment discloses a shear box for simulating lunar soil ring shear CT testing. Figure 5 The shear box used to simulate the lunar soil ring shear CT test includes a lower box body 1 and a loading pressure head 31. The lower box body 1 is fixedly arranged on the shear disk 6 of the ring shear instrument. During the shear test, the loading pressure head 31 remains stationary, and the lower box body 1 rotates with the shear disk 6.

[0041] Reference Figure 5 The lower box body 1 includes a lower box inner tube 12, a lower box outer tube 13, a bottom plate 14 and a base 11. The lower box inner tube 12 is fixedly connected to the base 11 by screws, the lower box outer tube 13 is fixedly connected to the base 11 by a slot structure, and the bottom plate 14 is fixedly connected to the lower box inner tube 12. The lower box inner tube 12 and the lower box outer tube 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 that contacts the sample 7, which is used to prevent the sample 7 and the bottom plate 14 from sliding relative to each other during the torsion shear process. The bottom plate 14 is made of breathable sintered brass.

[0042] The lower box outer cylinder 13 is made of transparent PEEK material, and may also be made of other transparent plastics, so as to facilitate observation of the shear surface of the sample 7 .

[0043] The loading head 31 is used to apply axial pressure to the sample 7, and its shape is adapted to the annular space in the lower box body 1. The loading head 31 has a cavity along its own axial direction for installing the temperature sensor 87.

[0044] In order to simulate the vacuum environment on the lunar surface, an exhaust channel can be opened through the base 11 and the inner tube 12 of the lower box, one end of the exhaust channel is connected to the bottom plate 14, and the other end is connected to the external vacuum environment; an exhaust channel can also be opened through the loading pressure head 31, one end of the exhaust channel is connected to the sample 7, and the other end is connected to the external vacuum environment.

[0045] Example 3 The present application embodiment discloses a test device for simulating lunar soil ring shear test, referring to Figure 6 and Figure 7 The testing device includes a ring shear instrument 8 and a shear box. The shear box includes a shear box for simulating lunar soil ring shear test disclosed in Example 1 or a shear box for simulating lunar soil ring shear CT test disclosed in Example 2; the ring shear instrument 8 includes a torsional shear measurement and control module 81, an axial load measurement and control module 82 and a sensor module; the ring shear instrument 8 also includes a shear box placement cabin 85 for placing the shear box.

[0046] The torsion shear measurement and control module 81 includes a shear disk and a motor for driving the shear disk to rotate. The base of the shear box is fixed on the shear disk. During the test, torque is applied to the sample through the rotation of the shear disk, and the torsion shear measurement and control module 81 collects stress data.

[0047] The axial loading measurement and control module 82 includes a reaction frame 83, an output end of which is connected to the axial loading assembly of the shear box, and is used to apply axial pressure to the sample and collect stress data.

[0048] The sensing module includes a temperature sensor 87 for measuring the sample temperature, an acoustic emission sensor 86 for monitoring the changes in the internal structure of the sample, and an LVDT sensor 84 for measuring the axial deformation of the sample. The acoustic emission sensor 86 is installed in the shear box placement cabin 85 and is located above the shear box. When using a shear box for simulating lunar soil ring shear test disclosed in Example 1, as shown in FIG. Figure 3 As shown, the temperature sensor 87 can be installed in the axial channel of the lower box inner tube 12; when a shear box for simulating lunar soil ring shear CT test disclosed in Example 2 is used, as shown in FIG. Figure 5 As shown, the temperature sensor 87 can be installed in the axial cavity of the loading head 31.

[0049] Example 4 The present application embodiment discloses a simulated lunar soil ring shear test method taking into account the lunar surface environment, using a test device for simulated lunar soil ring shear test disclosed in Example 3, and a shear box for simulated lunar soil ring shear test disclosed in Example 1. The test method includes the following steps: Step 1, assemble the shear box: install the shear box onto the shear plate 6.

[0050] Step 2. Fill the sample: Place the simulated lunar soil sample into the shear box.

[0051] Step 3, adjusting the shear seam width: Turn the shear seam adjusting ring 4 to make the shear seam 5 reach the set width, and tighten the adjusting bolt 26 to fix the width of the shear seam 5.

[0052] Step 4, test device preparation: 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 pressure head 31 contact with the top of the sample 7.

[0053] Step 5. Connection and environment setting: Place the test device in the lunar environment chamber, and connect the test device to the computer control system through the aviation plug adapter of the lunar environment chamber; adjust the vacuum degree, temperature and other parameters of the lunar environment chamber to the required test conditions.

[0054] Step 6, setting loading and collecting data: set the test loading steps on the computer side, apply axial force and torque to the sample 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 sample 7.

[0055] This method can repeat the mechanical test procedure of cyclic loading and unloading to study the residual deformation and particle motion characteristics of lunar soil under multiple stress conditions. A dynamic loading device can also be introduced to simulate the mechanical disturbance caused by the operation of lunar equipment or meteorite impact through high-frequency vibration or impact. Torque and axial force can also be applied simultaneously to study the friction between particles and force chain distribution of lunar soil under complex stress conditions.

[0056] In the test, particles of various sizes, shapes and materials can be mixed to simulate lunar soil to study the effect of particle grading on macroscopic mechanical properties. Micron-level coatings can be applied to the surface of simulated lunar soil particles to simulate the real physical and chemical properties of lunar soil particles and enhance the applicability of experimental results. A small amount of liquid can also be introduced between particles to simulate the ice-water effect that may exist at the lunar poles to study its effect on the mechanical properties of the soil.

[0057] Example 5 The present application embodiment discloses an in-situ CT simulated lunar soil mechanical testing method, which uses a testing device for simulating lunar soil ring shear testing disclosed in Example 3, and a shear box for simulating lunar soil ring shear CT testing disclosed in Example 2. The testing method includes the following steps: Step 1, assemble the shear box: install the shear box onto the shear plate 6.

[0058] Step 2. Fill the sample: Place the simulated lunar soil sample into the shear box.

[0059] Step 3, test device preparation: 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 pressure head 31 contact with the top of the sample 7.

[0060] Step 4: Place in industrial CT system: Place the entire test device on the turntable inside the industrial CT scanner; adjust the height of the radiation source so that it is accurately aligned with the sample 7 in the transparent shear box.

[0061] Step 5, loading and data acquisition: Set the loading step on the computer side, apply axial force and torque to the sample 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 temperature data near the sample 7.

[0062] Step 6, microscopic imaging and analysis: When the test reaches the preset data acquisition state point, the loading is suspended; the industrial CT turntable is started to drive the test device to rotate synchronously, and the sample 7 is scanned and imaged to obtain its microscopic change data under the load state.

[0063] This method can be used in conjunction with a multi-angle CT scanning device to perform 360° observations of lunar soil samples and improve the accuracy of reconstruction of particle motion trajectories. High-speed scanning technology can be introduced to capture the motion state of particles in real time during the shearing process, which is suitable for studying particle behavior under high-speed loading or vibration shearing conditions. Image processing and artificial intelligence technology can also be combined to identify particle boundaries and morphology through CT images, quantify particle deformation and its motion trajectory, and enhance data post-processing capabilities.

[0064] It should be noted that the test device and test method provided in this application can not only be used to simulate the mechanical properties of lunar soil, but also can be applied to the simulation and mechanical properties of soil on planets or satellites such as Mars and Europa. The test device can be appropriately modified to adapt to the high-pressure and low-temperature environment of the deep sea, and can also be used to study the movement characteristics of deep-sea soil particles.

[0065] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A shear box for simulating lunar soil ring shear testing, characterized in that: include: The lower box body is fixedly arranged on the shearing disk of the ring shear instrument, and the lower box body comprises a lower box inner cylinder and a lower box outer cylinder which are coaxially fixed, and an annular space for accommodating the sample is formed between the lower box inner cylinder and the lower box outer cylinder; a bottom plate in contact with the sample is arranged at the bottom of the lower box body, and the bottom plate is made of a breathable material; The upper box body comprises an upper box inner cylinder and an upper box outer cylinder which are coaxially fixed; the upper box body is rotatably arranged on the lower box body, and a gap arranged between the two is a shear gap; An axial loading assembly, used for applying axial pressure to the sample, comprising a loading pressure head slidably disposed in the upper box body along the axial direction of the upper box body, wherein the loading pressure head is made of a breathable material; A vacuum air channel, comprising an upper air pumping channel and a lower air pumping channel, wherein the upper air pumping channel is connected to the loading pressure head, and the lower air pumping channel is connected to the bottom plate, and both the upper air pumping channel and the lower air pumping channel are connected to an external vacuum environment; The shearing seam adjusting mechanism is used to adjust the width of the shearing seam.

2. A shear box for simulating lunar soil ring shear testing according to claim 1, characterized in that: The air-permeable material is air-permeable sintered brass.

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

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

5. A shear box for simulating lunar soil ring shear testing according to claim 1, characterized in that: The lower box inner tube and the upper box inner tube are both provided with inner ventilation channels, one end of the inner ventilation channels is in contact with the sample, and the other end is connected with the external vacuum environment.

6. A shear box for simulating lunar soil ring shear testing according to claim 5, characterized in that: The end of the inner ventilation channel in contact with the sample is provided with a filtering structure.

7. A shear box for simulating lunar soil ring shear testing according to claim 1, characterized in that: The shear seam adjustment mechanism includes a shear seam adjustment ring rotatably arranged on the shear disk, the shear seam adjustment ring is sleeved on the outside of the lower box outer tube, the upper end surface of the shear seam adjustment ring is provided with a plurality of inclined surfaces at intervals, and the inclination direction of the inclined surfaces extends along the circumferential direction of the shear seam adjustment ring; a plurality of protrusions corresponding to the inclined surfaces are fixedly arranged on the outer peripheral side of the upper box outer tube, and each of the protrusions abuts against the corresponding inclined surface.

8. A shear box for simulating lunar soil ring shear testing according to claim 7, characterized in that: A plurality of nuts are fixedly arranged on the outer circumference of the upper box outer cylinder, each of the nuts is threadedly connected with an adjusting bolt, and the adjusting bolt is vertically arranged and its bottom end abuts against the upper end surface of the shearing disk.

9. A test device for simulating lunar soil ring shear test, characterized in that: The invention comprises a ring shear instrument and a shear box, wherein the shear box comprises a shear box for simulating lunar soil ring shear test according to any one of claims 1 to 8, and the ring shear instrument comprises: Torsion shear measurement and control module, used to apply torque to the specimen and collect stress data; Axial loading measurement and control module, used to apply axial pressure to the sample and collect stress data; The sensing module includes a temperature sensor for measuring the temperature of the sample, an acoustic emission sensor for monitoring the changes in the internal structure of the sample, and an LVDT sensor for measuring the axial deformation of the sample.

10. A test device for simulating lunar soil ring shear test according to claim 9, characterized in that: The shear box also includes a shear box for simulating lunar soil ring shear CT testing.

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