In-situ loading tensile testing device and method for particulate matter based on CT (Computed Tomography) scanning

Abstract

The invention discloses a particulate matter in-situ loading test device and method based on industrial CT scanning, and relates to the field of thermal machinery, and the particulate matter in-situ loading test device comprises a driving assembly, a sensor unit, a clamp assembly, a carbon fiber bearing cylinder, a heat insulation cylinder, a heating module, a gas charging and discharging system and a sensor cooling protection unit. The periphery of the clamp assembly is additionally provided with a heat insulation cylinder to form a closed space so as to ensure that a sample can be experimented in a specific gas atmosphere; the heating mode adopts a heating disc to heat and introduce gas so as to uniformly heat the sample; the top of the device is connected with a quick-plug water nozzle which can be connected with a water cooling machine; the loading base is connected with the CT rotary table in a screw locking mode. The thermal mechanical change process of the particle ball bed under different thermal stress and gas atmospheres can be fully simulated, and the loading process and the internal microstructure change of the sample can be scanned in situ in cooperation with industrial CT scanning while the sample is heated and loaded.

Description

Technical Field

[0001] The present invention relates to the field of thermomechanics, in particular to material mechanical property testing and the field of material internal structure monitoring compatible with industrial CT, and specifically to an in-situ loading tensile testing device and method for granular material for CT scanning. Background Art

[0002] Granular matter is a system composed of a large number of discrete solid particles. Granular matter has the fluidity of fluids and the strong compressive resistance of solids, so it is widely used in the industrial field. In the solid blanket design of fusion reactors, tritium breeders and neutron multipliers are usually present in the blanket in the form of particles. These particles are accommodated in a mixed filling manner to form a pebble bed structure. The initial particle size distribution of these particles is uniform and randomly stacked. This means that the surface of a single particle may contact multiple adjacent particles, resulting in a very complex stress environment. Therefore, the stress distribution in the pebble bed shows obvious inhomogeneity, and particles may break due to poor local stress conditions, resulting in changes in the pebble bed structure.

[0003] In addition, in the field of material mechanics analysis, traditional mechanical testing equipment only applies force to the specimen to obtain material-related data and macroscopic fracture phenomena; or the specimen is only used in a natural state to study the internal structure of the material under an industrial CT imaging system. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an in-situ loading test device and method for particulate matter based on industrial CT scanning. When a load is applied to a sample under an industrial CT imaging system and heated at the same time, a thermodynamic testing technology can be used to observe the internal structural changes and microscopic deformation damage of the sample under the combined influence of external force and temperature, which can achieve the synchronization of material performance testing and microstructure observation, and provide more comprehensive theoretical data in the form of studying material structural deformation. The present invention adopts a method of heating the sample by passing gas, and performs a surrounding heating of the sample, which can make the sample heated evenly, and solves the heating problem of low thermal conductivity materials, and can cover a variety of sample material types. At the same time, the sample's load-bearing barrel is made of carbon fiber material, which can pass through X-rays, which is conducive to the industrial CT to obtain clearer images when scanning the sample. The present invention is a thermodynamic testing technology that performs full-process dynamic monitoring of the internal structural changes and microscopic deformation damage of the material under the industrial CT imaging system, and provides comprehensive theoretical data in the form of studying material failure.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A particle material in-situ loading tensile testing device for CT scanning, comprising a drive assembly, a fixture assembly, a carbon fiber bearing tube, a heat insulation tube, a heating module, and a gas filling and exhausting system; the drive assembly is integrated in a loading base; the fixture assembly is divided into a tensile fixture and a loading pressure head according to function, the tensile fixture comprises an upper tensile fixture and a lower tensile fixture, and the loading pressure head comprises an upper pressure head and a lower pressure head; the lower tensile fixture or the lower pressure head is connected to the loading base, and the upper tensile fixture or the upper pressure head is connected to an upper cover plate; a guide hole is provided at the bottom of the upper cover plate for connecting a guide rod, and a guide hole is provided at the upper part of the loading base, and the guide rod The upper cover plate and the loading base are connected through guide holes to ensure the coaxiality of the upper tensile fixture and the lower tensile fixture; the carbon fiber bearing tube is placed between the upper pressure head and the lower pressure head; an insulation tube is arranged outside the upper tensile fixture and the lower tensile fixture or the upper pressure head and the lower pressure head to form a sealed whole; a gas inlet is welded on the top of the upper cover plate, and the gas inlet is connected to the gas filling and exhaust system; the top of the upper cover plate and the loading base are designed with water inlets and outlets, which are respectively connected to the water inlet pipe and the water outlet pipe of the water cooler; the heating module heats the gas after entering the insulation tube to heat the environment of the tensile specimen or the compression specimen.

[0007] Furthermore, the gas in the gas filling and exhaust system is provided by a gas source, and the gas enters the gas inlet of the loading and tensile testing device through a pressure reducing valve, a one-way valve and a three-way valve, and one end of the three-way valve is connected to a vacuum pump; the gas is heated to a specified temperature through a heating plate, enters the insulation cylinder and heats the compression sample or the tensile sample in the carbon fiber bearing cylinder.

[0008] Furthermore, the tensile specimen is placed between the upper tensile fixture and the lower tensile fixture and fastened; two rectangular hanging ears are welded on the sides of the lower tensile fixture, and guide holes are provided in the rectangular hanging ears, and guide rods are inserted to ensure the coaxiality and connection of the upper tensile fixture and the lower tensile fixture.

[0009] Furthermore, a protrusion is provided at the bottom of the carbon fiber supporting tube, which is embedded in the three concave holes on the lower pressure head for positioning.

[0010] Furthermore, an O-ring groove is provided on the side of the upper stretching fixture and the lower stretching fixture, and an O-ring rubber ring is installed in the O-ring groove. The upper stretching fixture and the lower stretching fixture are nested in the insulation tube and connected to form a sealed whole.

[0011] Furthermore, it also includes a sensor unit and a sensor cooling unit, the sensor cooling unit includes a water cooler and a quick-plug water nozzle, the top of the upper cover plate is connected to two quick-plug water nozzles, which are the water inlet and the water outlet of the upper stretching clamp respectively; the loading base is connected to two quick-plug water nozzles, which are the water inlet and the water outlet of the lower stretching clamp respectively; the quick-plug water nozzles are respectively connected to the water outlet and the return water of the water cooler.

[0012] Furthermore, the heating module includes a temperature control unit and a heating wire quick-plug connector; the heating wire quick-plug connector is used to connect the cable to the energized heating plate; the temperature control unit is used to control the heating power of the heating plate and detect the temperature of the gas.

[0013] Furthermore, the insulation tube is divided into an upper insulation tube, a middle insulation tube and a lower insulation tube; the upper insulation tube is connected to the upper cover plate for installing an upper stretching clamp and an upper pressure head; the lower insulation tube is connected to the loading base for installing a lower stretching clamp and a lower pressure head; the middle installation tube is used to close the space for relative movement of the lower pressure head relative to the upper pressure head and the upper stretching clamp relative to the lower stretching clamp.

[0014] The present invention also provides a loading and stretching test method using the above-mentioned in-situ loading and stretching test device for CT scanning of particulate matter, comprising the following steps:

[0015] Step 1: Before the experiment, power on the electric control cabinet and turn on the control computer;

[0016] Step 2: Select the tensile fixture and loading head according to the experimental purpose;

[0017] Step 3: Connect the loading tensile test device to the CT equipment;

[0018] Step 4: Connect the water inlet and outlet of the water cooler to the quick-plug water nozzle respectively; connect one end of the heating cable and the signal transmission cable to the electric control cabinet, and insert the other end of the heating cable into the heating wire quick-plug connector; connect the gas delivery pipeline to the gas inlet, and complete the preparation before the experiment;

[0019] Step 5: At the beginning of the experiment, the loading tensile test device is vacuumed; after the vacuuming is completed, the gas source is turned on and the pressure reducing valve is adjusted until the gas concentration reaches the standard;

[0020] Step 6: Set the required temperature according to the test requirements and wait for the gas temperature to rise to the set temperature;

[0021] Step 7: After the temperature stabilizes, set the pressure required for the experiment;

[0022] Step 8: Clear the current force value and complete the force value reset to zero;

[0023] Step 9: Load the tensile specimen or the compression specimen according to the experimental requirements and scan it using the CT device;

[0024] Step 10: After the scanning and loading or stretching process is completed, the heating plate is controlled to stop heating; after the internal temperature of the loading and stretching test device cools down, the power supply of the electric control cabinet is disconnected, the loading and stretching test device is disassembled, the tensile specimen or compression specimen is taken out, and the experiment is ended.

[0025] The beneficial effects of the present invention compared with the prior art are:

[0026] (1) The present invention adopts a method of heating the sample by introducing helium gas, and performs surrounding heating on the sample, which can make the sample heated evenly and solve the heating problem of low thermal conductivity materials, and can cover a variety of sample material types.

[0027] (2) The sample carrying tube in the present invention is made of carbon fiber, which can transmit X-rays, which is beneficial for the industrial CT to obtain clearer images when scanning the sample.

[0028] (3) The present invention adopts a water cooling method, which can ensure that the temperature of other components inside the host will not be too high while the temperature of the sample rises.

[0029] (4) The present invention can select a suitable fixture assembly according to different experimental requirements, and complete the tensile and loading test functions of the sample in a set of loading and tensile testing equipment.

[0030] In summary, the present invention can be used to simulate the thermal stress environment of particles in a ball bed. After applying a certain pressure and temperature to the ball bed particles, the ball bed structure and the distribution of broken particles after the particles are broken are measured, revealing the thermal mechanical properties of the ball bed after the particles are broken, and providing data support for the design and research of granular ball beds.

[0031] At the same time, the present invention can be integrated on an industrial CT turntable, and a certain load force is applied to the sample and gas is introduced for heating. At this time, the sample can be scanned and photographed 360 degrees through the rotation of the CT turntable, which is helpful for in-depth research on the structural changes and microscopic deformation and damage principles of the material under stress and heating conditions, and reveals the thermodynamic behavior, crushing mechanism and thermomechanical properties of various samples related to load effects and material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a three-dimensional cross-sectional view of an in-situ loading tensile testing device for CT scanning of granular materials according to the present invention;

[0033] Figure 2 is a schematic diagram of the tensile fixture structure;

[0034] Figure 3 is a schematic diagram of the system for the load test experiment;

[0035] FIG4a is a bottom view of the carbon fiber bearing tube;

[0036] Figure 4b shows Figure 4a AA section view;

[0037] Figure 5 is a front view of the tensile specimen.

[0038] Among them, the accompanying drawings are marked as follows: 1 is a driving component; 2 is a sensor unit; 3 is a loading base; 4 is a carbon fiber bearing tube; 5 is an upper pressure head; 6 is a lower pressure head; 7 is an insulation tube; 8 is an upper cover plate; 9 is a quick-plug water nozzle; 10 is a gas inlet; 11 is a heating wire quick-plug connector; 12 is a heating plate; 13 is a quick-release fixed base plate; 14 is a tensile specimen; 15 is a guide rod; 16 is an upper tensile fixture; 17 is an upper tensile fixture; 18 is an O-type rubber ring; 19 is an air source; 20 is a pressure reducing valve; 21 is a one-way valve; 22 is a three-way valve; 23 is a vacuum pump; 24 is a water cooler; 25 is a gas control unit; 26 is a temperature control unit; 27 is an electronic control unit; 28 is a control computer host; 29 is a control computer display; 30 is an electronic control cabinet; 31 is a CT device; 32 is a locking screw, and 33 is a loading and tensile test device. DETAILED DESCRIPTION

[0039] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying 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.

[0040] like Figure 1 As shown, an in-situ loading tensile testing device for particulate matter for CT scanning of the present invention includes a driving component 1, a sensor unit 2, a loading base 3, a clamp assembly, a carbon fiber bearing tube 4, an insulation tube 7, a heating plate 12, a gas filling and exhaust system, a heating module, and a sensor cooling protection unit.

[0041] Among them, the driving component 1 and the sensor unit 2 are integrated in the loading base 3; the fixture component can be divided into a tensile fixture and a loading head according to the function, the tensile fixture can be divided into an upper tensile fixture 16 and a lower tensile fixture 17 according to the installation position, and the loading head can be divided into an upper head 5 and a lower head 6 according to the installation position. By replacing the tensile fixture and the loading head, the corresponding tensile test and loading test can be carried out. The sensor unit 2 is used to monitor the parameters of the cooling water.

[0042] During the loading test, the granular material is filled in the carbon fiber bearing tube 4, such as Figure 4a , Figure 4bAs shown, the base of the carbon fiber bearing tube 4 has a boss, and the upper surface of the lower pressure head 6 has three circular holes for positioning. In addition, the outer diameter of the upper pressure head 5 and the inner diameter of the carbon fiber bearing tube 4 can be replaced according to the needs of the experiment. The upper end of the loading and tensile testing device is a quick-plug water nozzle 9, a gas inlet 10 and a heating wire quick-plug connector 11. These three components are welded to the upper surface of the upper cover plate 8 by welding. The quick-plug water nozzle 9 is connected to the water cooler 24 in the electric control cabinet 30 through a rubber pipe. After the experiment starts, the water cooler 24 works to control the circulation of the coolant in the loading and tensile testing device to cool the upper pressure head 5 and the lower pressure head 6 to achieve the effect of protecting the pressure head in a high temperature environment. The gas inlet 10 is connected to the gas control unit 25 through a pipeline. After the experiment starts, the gas control unit 25 controls the gas to enter the heating plate 12 through the gas inlet 10 for heating. The heating wire quick plug connector 11 integrates the functions of power-on heating and model transmission. The heating wire quick plug connector 11 is connected to the temperature control unit 26 through wires and cables to power on the heating plate 12 for heating. In addition, the signal line of the thermal probe integrated in the loading and tensile testing device is also connected to the temperature control unit 26 through the heating line quick connector 11, which is used to detect the temperature inside the loading and tensile testing device in real time. The heating plate 12 is integrated inside the upper cover plate 8. The upper pressure head 5 is connected to the lower surface of the upper cover plate 8 by a hexagonal screw. The lower pressure head 6 is quickly connected to the upper surface of the loading base 3 by a hexagonal screw. The carbon fiber bearing tube 4 is placed on the upper part of the lower pressure head 6. In addition, an O-ring groove is designed on the side of the upper pressure head 5 and the lower pressure head 6, and an O-ring rubber ring 18 can be installed. The insulation tube 7 is arranged below the upper cover plate 8, which can surround the upper pressure head 5, the lower pressure head 6 and the middle carbon fiber bearing tube 4, and cooperate with the O rubber ring 18 to form a sealed space. The drive assembly 1 and the sensor unit 2 are both integrated inside the loading base 3. The quick-release fixing base plate 13 is fixed to the CT device 31 by hexagonal screws. When the CT device 31 is used for scanning, the loading tensile test device 33 can be placed on the quick-release fixing plate 13 and the position can be quickly fixed and installed by tightening the screws 32 .

[0043] like Figure 2 As shown, the upper tensile fixture 16 is connected to the lower surface of the upper cover plate 8 by hexagonal screws, and the lower tensile fixture is installed on the upper part of the loading base by hexagonal screws. The guide rod 15 and the tensile specimen 14 are located in the middle of the upper tensile fixture 16 and the upper tensile fixture 17. In addition, an O-ring groove is designed on the side of the upper tensile fixture 16 and the upper tensile fixture 17, and an O-ring rubber ring 18 can be installed. The heat insulation tube 7 is provided to surround the upper tensile fixture 16, the upper tensile fixture 17, the tensile specimen 14 in the middle, and the guide rod 15, and cooperate with the O rubber ring 18 to form a sealed space. The enclosed space can ensure that the sample is loaded or stretched in a specific gas atmosphere, and different gas atmospheres can be achieved by replacing different gas sources.

[0044] During the tensile test, the tensile specimen 14 needs to be installed between the upper tensile fixture 16 and the lower tensile fixture 17. In addition, the sides of the upper tensile fixture 16 and the lower tensile fixture 17 have guide holes for inserting the guide rod 15 to ensure the coaxiality during the stretching process. The upper end of the loading tensile test device is a quick-plug water nozzle 9, a gas inlet 10, and a heating wire quick-plug connector 11. These three components are welded to the upper surface of the upper cover plate 8 by welding. The quick-plug water nozzle 9 is connected to the water cooler 24 in the electric control cabinet 30 through a rubber pipe. After the experiment starts, the water cooler works to control the circulation of the coolant in the loading tensile test device to cool the upper tensile fixture 16 and the lower tensile fixture 17 to achieve the role of protection in a high temperature environment. The gas inlet 10 is connected to the gas control unit 25 through a pipeline. After the experiment starts, the gas control unit 25 controls the gas to enter the heating plate through the gas inlet 10 for heating. The heating wire quick plug connector 11 integrates the functions of power-on heating and model transmission. The heating wire quick plug connector 11 is connected to the temperature control unit 26 through electric wires and cables, and is used to power on and heat the heating plate 12. In addition, the signal line of the thermal probe integrated in the loading and stretching test device is also connected to the temperature control unit 26 through the heating wire quick plug connector 11, and is used to detect the temperature inside the loading and stretching test device in real time. The heating plate 12 is integrated inside the upper cover plate 8.

[0045] like Figure 3 As shown, the gas filling and exhaust system includes a gas source 19, a pressure reducing valve 20, a one-way valve 21, and a three-way valve 22; the heating method uses a heating plate 12 to heat the incoming gas and then heat the sample. The advantage of this heating method is that the internal sample temperature can be evenly increased and the gas temperature can be more accurately controlled. The gas enters the heating plate 12 through the gas inlet 10, and after being heated, enters the insulation cylinder to evenly heat the sample.

[0046] A pressure reducing valve 20 is installed at the outlet of the gas source 19, and the pressure reducing valve 20 can control the opening and closing of the gas source 19 and adjust the outlet pressure. The pressure reducing valve 20 is connected to a one-way valve 21, and the one-way valve 21 can prevent gas backflow. The one-way valve 21 is connected to a three-way valve 22, and one end of the three-way valve 22 is connected to a gas control unit 25, and the other end is connected to a vacuum pump 23. The vacuum pump is used to evacuate the air before the experimental preparation stage to ensure that the inside of the device has a vacuum degree of one degree. The gas control unit 25 is used to control the gas flow and circulation in the device.

[0047] The temperature control unit 26 integrates the functions of controlling electric heating and thermal signal processing, and is connected to the heating wire quick plug connector 11 through wires and cables. The water cooler 24 controls the circulation of the coolant in the loading and stretching test device, and is connected to the quick plug nozzle 9 through a rubber hose. In addition, the vacuum pump 23, the water cooler 24, the gas control unit 25, the temperature control unit 26, the electric control unit 27, and the control computer host 28 are all integrated in the electric control cabinet 30 according to the installation position from bottom to top, wherein the electric control unit 27 is responsible for providing the required power for other devices in the electric control cabinet. The control computer host 28 is connected to the control computer display 29, and the control of the loading and stretching test device is completed through the control software.

[0048] Furthermore, the loading base 3 can be connected to the industrial CT turntable, that is, the loading tensile testing device 33 can be quickly connected to the CT equipment 31 through the quick-release fixing base plate 13 .

[0049] Furthermore, the insulation tube 7 can be divided into three sections, upper and lower, including: an upper insulation tube, used to install the upper stretching clamp 16 and the upper pressure head 5; a lower insulation tube, used to install the lower stretching clamp 17 and the lower pressure head 6, connected to the loading base 3; a middle installation tube is used to close the space for the relative movement of the lower pressure head 6 relative to the upper pressure head 5, and the upper stretching clamp 16 relative to the lower stretching clamp 17; during installation, they are fixedly connected in sequence from top to bottom.

[0050] Furthermore, if Figure 5 As shown, the tensile specimen 4 is symmetrically fan-shaped, with a neck in the middle, an opening angle of the neck is 90 degrees, and the angle of the fan is 45 degrees. degree. The tensile fixture for the tensile specimen 14 has a groove corresponding to the shape of the tensile specimen 14. After the tensile specimen 14 is placed in the groove, it can be fastened with screws. The loading head used in the loading experiment needs to be used in conjunction with a special carbon fiber bearing tube 4. The diameter of the upper pressure head 5 is the same as the inner diameter of the carbon fiber bearing tube 4. The upper surface of the lower pressure head 6 has three circular holes, which cooperate with the boss at the bottom of the carbon fiber bearing tube 4 for positioning. During the loading experiment, the particulate matter is filled in the carbon fiber bearing tube 4 to form a particle ball bed. The lower pressure head 6 is driven upward by the driving assembly 1 to realize the loading of the particle ball bed in the carbon fiber bearing tube 4 by the upper pressure head 5 and the lower pressure head 6.

[0051] Furthermore, if Figure 3 As shown, before the experiment begins, the entire system is evacuated using a vacuum pump 23. When the vacuum degree in the system reaches the required level, the gas source 19 is opened, and the gas enters the gas inlet 10 of the loading and tensile testing device through the pressure reducing valve 20, the one-way valve 21 and the three-way valve 22. The gas is heated to a specified temperature in the heating plate 12, enters the insulation cylinder 7, and uniformly heats the sample.

[0052] Furthermore, the heating module includes a temperature control unit 26, a heating wire quick-plug connector 11, and a heating plate 12. The top of the upper cover plate 8 is provided with a heating wire quick-plug connector 11 for connecting the cable for power heating; the temperature control unit 26 is used to control the temperature, control the heating power of the heating plate 12 and detect the gas temperature.

[0053] Furthermore, the sensor cooling protection unit comprises a sensor unit 2, a quick-plug water nozzle 9 and a water cooler 24. The upper end of the upper cover plate 8 has two quick-plug water nozzles 9, which are cooling water inlet and cooling water outlet, respectively, connected to the water outlet and return water of the water cooler 24.

[0054] The present invention also provides a loading tensile test method of a particulate matter in-situ loading test device based on industrial CT scanning, which can observe the internal structure and microstructure of a sample under the combined influence of loading and heating based on industrial CT, comprising the following steps:

[0055] Step 1: Before the experiment, power on the electric control cabinet 30, turn on the power of the control computer 27, and open the loading system operating software and the gas heating system software.

[0056] Step 2: Select the required tensile fixture and loading head according to the experimental purpose.

[0057] During the tensile test, before installing the tensile specimen, the upper tensile fixture 17 must be controlled to move upward through the loading system operating software to leave enough space for the subsequent installation of the fixture and the specimen. An O-ring 18 is installed in each of the O-ring grooves of the upper tensile fixture 16 and the upper tensile fixture 17, an insulation tube 7 is set, and the screws of the upper tensile fixture 17 are installed on the loading base 3. One end of the tensile specimen 14 is installed in the upper tensile fixture 16 with bolts. Then insert the two guide rods 15 into the guide holes of the upper tensile fixture 16, and then insert the entire rod into the guide holes of the upper tensile fixture 17. The lower end of the tensile specimen 14 is installed with the upper tensile fixture 17 and fastened with screws. Operate the loading tensile test device operating software to control the drive assembly 1 to make the upper tensile fixture 17 move downward, so that the bottom of the guide rod 15 fits with the loading base 3, and ensures sealing.

[0058] During the loading experiment, before installing the compression specimen, it is necessary to first control the lower pressure head 6 to move downward through the operating software of the loading and tensile testing device to leave enough space for the subsequent installation of the upper pressure head 5 and the carbon fiber bearing tube 4. According to the test requirements, select a suitable upper pressure head 5 and install it in the upper cover plate 8 and fasten it with screws. Install an O-ring rubber ring 18 in the O-ring groove of the upper pressure head 5, and set the insulation tube 7. Load the compression specimen into the carbon fiber bearing tube 4, and place the carbon fiber bearing tube 4 on the lower pressure head 6. Then install the insulation tube 7 and the upper pressure head 5 as a whole on the loading base 3. Operate the operating software of the loading and tensile testing device to control the drive assembly 1 to make the lower pressure head 6 move upward until the upper surface of the specimen in the carbon fiber bearing tube 4 contacts the surface of the upper pressure head 5.

[0059] Step 3: Connect the loading and stretching test device to the CT device 31 . The bottom of the loading and stretching test device 33 has three locking screws 32 and a quick-release fixing base plate 13 , which can facilitate the installation and removal of the loading and stretching test device and the CT device 31 .

[0060] Step 4: Connect the water inlet and outlet of the water cooler 24 to the quick-plug water nozzle 9 respectively. Connect one end of the heating cable and the signal transmission cable to the electric control cabinet 30, and insert the other end of the cable into the heating cable quick plug connector 11. Connect the gas delivery pipeline to the gas inlet 10 to complete the preparation before the experiment.

[0061] Step 5: At the beginning of the experiment, the loading system is evacuated. After the evacuation is completed, the gas source 19 is opened and the pressure reducing valve 20 is adjusted until the gas concentration reaches the standard.

[0062] Step 6: According to the test requirements, set the required temperature in the gas heating system software and wait for the gas temperature to rise to the set temperature.

[0063] Step 7: After the temperature stabilizes, set the required pressure for the experiment. If the required pressure is lower than the current system pressure, directly set the pressure value in the pressure setting of the gas heating system software and click Set. If the required pressure is higher than the current system pressure, the system pressure needs to be manually adjusted at the pressure reducing valve 20 of the gas source 19.

[0064] Step 8: Clear the current force value in the gas heating system software and complete the force value reset to zero.

[0065] Step 9: Load the sample according to experimental requirements and scan it using the CT device 31.

[0066] Step 10: After the scanning and loading process is completed, the heating plate 12 is controlled to stop heating. After the system cools down, the power supply of the electric control cabinet 30 is disconnected, the loading and tensile testing device is disassembled, the tensile specimen or the compression specimen is taken out, and the experiment is ended.

[0067] The parts not described in detail in the present invention belong to the common knowledge in the art.

[0068] Although the above content describes the illustrative specific embodiments of the present invention to facilitate the understanding of the present invention by those skilled in the art, it should be clear that the present invention is not limited to the scope of the specific embodiments, and it is obvious to those skilled in the art that various changes are within the spirit and scope of the appended claims and the present invention, and are all protected by the present invention.

Claims

1. An in-situ loading tensile testing device for granular material for CT scanning, characterized in that: It includes a drive assembly, a fixture assembly, a carbon fiber bearing tube, an insulation tube, a heating module, and a gas filling and exhaust system; the drive assembly is integrated in the loading base; the fixture assembly is divided into a stretching fixture and a loading pressure head according to the function, the stretching fixture includes an upper stretching fixture and a lower stretching fixture, and the loading pressure head includes an upper pressure head and a lower pressure head; the lower stretching fixture or the lower pressure head is connected to the loading base, and the upper stretching fixture or the upper pressure head is connected to the upper cover plate; a guide hole is provided at the bottom of the upper cover plate for connecting a guide rod, and a guide hole is provided at the upper part of the loading base, and the guide rod is connected to the upper cover plate and the loading base through the guide hole A loading base is provided to ensure the coaxiality of the upper tensile fixture and the lower tensile fixture; the carbon fiber bearing cylinder is placed between the upper pressure head and the lower pressure head; an insulation cylinder is arranged outside the upper tensile fixture and the lower tensile fixture or the upper pressure head and the lower pressure head to form a sealed whole; a gas inlet is welded on the top of the upper cover plate, and the gas inlet is connected to the gas filling and exhaust system; the top of the upper cover plate and the loading base are designed with water inlets and outlets, which are respectively connected to the water inlet pipe and the water outlet pipe of the water cooler; the heating module heats the gas after entering the insulation cylinder to heat the environment of the tensile specimen or the compression specimen.

2. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: The gas in the gas filling and exhausting system is provided by a gas source, and the gas enters the gas inlet of the loading and tensile testing device through a pressure reducing valve, a one-way valve and a three-way valve, and one end of the three-way valve is connected to a vacuum pump; the gas is heated to a specified temperature through a heating plate, enters the insulation cylinder and heats the compression sample or the tensile sample in the carbon fiber bearing cylinder.

3. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: The tensile specimen is placed between the upper tensile fixture and the lower tensile fixture and fastened; two rectangular hanging ears are welded on the sides of the lower tensile fixture, and guide holes are provided in the rectangular hanging ears, and guide rods are inserted to ensure the coaxiality and connection of the upper tensile fixture and the lower tensile fixture.

4. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: The bottom of the carbon fiber bearing cylinder is provided with a protrusion which is embedded in the three concave holes on the lower pressure head for positioning.

5. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: The sides of the upper and lower stretching fixtures are each provided with an O-ring groove, and an O-ring rubber ring is installed in the O-ring groove. The upper and lower stretching fixtures are nested in the insulation tube and connected to form a sealed whole.

6. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: It also includes a sensor unit and a sensor cooling unit, wherein the sensor cooling unit includes a water cooler and a quick-plug water spout, the top of the upper cover plate is connected to two quick-plug water spouts, which are respectively the water inlet and the water outlet of the upper stretching fixture; the loading base is connected to two quick-plug water spouts, which are respectively the water inlet and the water outlet of the lower stretching fixture; the quick-plug water spouts are respectively connected to the water outlet and the return water of the water cooler.

7. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: The heating module includes a temperature control unit and a heating wire quick-plug connector; the heating wire quick-plug connector is used to connect the cable to the energized heating plate; the temperature control unit is used to control the heating power of the heating plate and detect the temperature of the gas.

8. The in-situ loading tensile testing device for CT scanning of particulate matter according to claim 1, characterized in that: The insulation tube is divided into an upper insulation tube, a middle insulation tube and a lower insulation tube; the upper insulation tube is connected to the upper cover plate and is used to install the upper stretching clamp and the upper pressure head; the lower insulation tube is connected to the loading base and is used to install the lower stretching clamp and the lower pressure head; the middle installation tube is used to close the space for the relative movement of the lower pressure head relative to the upper pressure head and the upper stretching clamp relative to the lower stretching clamp.

9. A loading and stretching test method using the in-situ loading and stretching test device for CT scanning of particulate matter according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Before the experiment, power on the electric control cabinet and turn on the control computer; Step 2: Select the tensile fixture and loading head according to the experimental purpose; Step 3: Connect the loading tensile test device to the CT equipment; Step 4: Connect the water inlet and outlet of the water cooler to the quick-plug water nozzle respectively; connect one end of the heating cable and the signal transmission cable to the electric control cabinet, and insert the other end of the heating cable into the heating wire quick-plug connector; connect the gas delivery pipeline to the gas inlet, and complete the preparation before the experiment; Step 5: At the beginning of the experiment, the loading tensile test device is vacuumed; after the vacuuming is completed, the gas source is turned on and the pressure reducing valve is adjusted until the gas concentration reaches the standard; Step 6: Set the required temperature according to the test requirements and wait for the gas temperature to rise to the set temperature; Step 7: After the temperature stabilizes, set the pressure required for the experiment; Step 8: Clear the current force value and complete the force value reset to zero; Step 9: Load the tensile specimen or the compression specimen according to the experimental requirements and scan it using the CT device; Step 10: After the scanning and loading or stretching process is completed, the heating plate is controlled to stop heating; after the internal temperature of the loading and stretching test device cools down, the power supply of the electric control cabinet is disconnected, the loading and stretching test device is disassembled, the tensile specimen or compression specimen is taken out, and the experiment is ended.

10. The loading and stretching method according to claim 9, characterized in that: The step 2 comprises: When conducting a tensile test, before installing the tensile specimen, control the upper tensile fixture to move upward; install an O-type rubber ring in the O-type ring groove of the upper tensile fixture and the lower tensile fixture, set up a heat insulation cylinder, and install the upper tensile fixture on the loading base; install one end of the tensile specimen into the upper tensile fixture; then insert the two guide rods into the guide holes of the upper tensile fixture, and then insert the entire rod into the guide holes of the upper tensile fixture; the lower end of the tensile specimen is fixed to the upper tensile fixture; set the upper tensile fixture to run downward so that the bottom of the guide rod fits the loading base and ensures sealing; When conducting a loading experiment, before installing the compression specimen, control the lower pressure head to move downward; according to the test requirements, select the upper pressure head to install it in the upper cover plate and tighten it; install an O-ring rubber ring in the O-ring groove of the upper pressure head, and set up a thermal insulation tube; load the compression specimen into the carbon fiber bearing tube, and place the carbon fiber bearing tube on the lower pressure head; then install the thermal insulation tube and the upper pressure head as a whole on the loading base; set the lower pressure head to move upward until the upper surface of the specimen in the carbon fiber bearing tube contacts the surface of the upper pressure head.

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