Rheological shear test experimental device based on in-situ CT imaging analysis

Abstract

The invention relates to the technical field of magnetorheological fluid detection, in particular to a rheological shear test experimental device based on in-situ CT imaging analysis. A liquid containing barrel is arranged on the surface of the shearing experiment table, a heating piece is arranged at the bottom of the liquid containing barrel, a Hall piece is arranged on the inner wall of the liquid containing barrel, a lifting frame is arranged above the shearing experiment table and moves in the vertical direction, a U-shaped frame is arranged at the bottom of the lifting frame, a protection assembly is arranged in the U-shaped frame, and a groove is formed in the shearing experiment table. The lifting frame is controlled to move downwards in the vertical direction, in the moving process, the flow guide plate makes contact with magnetorheological fluid, due to the fact that the bottom of the flow guide plate is in a conical shape, the resistance of the flow guide plate in the moving process can be reduced, and due to the fact that the flow guide plate is attached to the bottom of the shearing blade in the moving process, the shearing efficiency is improved. Therefore, the shear blade is prevented from being deformed due to overlarge resistance in the moving process, and the service life of the shear blade is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetorheological fluid detection, and more specifically, to a rheological shear test experimental device based on in-situ CT imaging analysis. Background Art

[0002] Magnetorheological fluid is a new type of intelligent material with good development prospects and engineering application value. Under the action of an external magnetic field, it will undergo a millisecond-level reversible transformation between solid and liquid, thus producing an obvious magnetorheological effect. As an important tool for characterizing the rheological properties of magnetorheological fluid (MRF), traditional rheometers mainly rely on measuring macroscopic shear stress, viscosity and other parameters to reflect the response characteristics of materials under different stress states. Shear yield stress is an index to measure the solidification strength of magnetorheological fluid under the action of a magnetic field and is the main mechanical property parameter of magnetorheological fluid. Therefore, it is particularly important to develop a test device that can accurately measure the shear yield stress of magnetorheological fluid for evaluating the mechanical properties of magnetorheological fluid.

[0003] Regarding the test experimental device, there are many existing technologies, for example:

[0004] Chinese Patent Publication No. CN110631928B discloses a magnetorheological fluid shear yield stress test device, which consists of a control module, a magnetic field generating device with a uniform and adjustable magnetic field, a shearing device, a collecting device, and a power supply for supplying power to the magnetic field generating device, the shearing device and the controller; among them, the magnetic field generating device includes a closed structure made of pure iron for electrical engineering and a magnetic field and temperature measuring device. The closed structure is internally provided with a titanium alloy sleeve and a conductive coil wound around it. A titanium alloy liquid storage bucket is placed inside the titanium alloy sleeve. The shearing device includes a rotating motor and a shearing shaft; the collecting device includes Hall, temperature, and torque sensors. The Hall and temperature sensors are placed inside the magnetic field generating device, and the torque sensor is arranged on the shearing shaft; compared with the prior art, the present invention has the advantages of simple structure, easy operation, good stability, accurate measurement results, etc.

[0005] However, in the actual use process, there are still some problems:

[0006] 1. At present, in the test process of traditional test experimental devices, the magnetic induction intensity of magnetorheological fluid is changed by simply controlling the on-off of the coil. This regulation method has obvious deficiencies. First, the magnetic field distribution is uneven, making it difficult to achieve precise control and uniform application of the magnetic field intensity inside the magnetorheological fluid, resulting in inconsistent responses of different parts of the magnetorheological fluid during the test; second, the magnetic field intensity adjustment range is limited and lacks flexibility, and it cannot meet the diverse requirements for different intensities and different gradient magnetic fields under complex experimental conditions, greatly limiting the in-depth study of the performance of magnetorheological fluid under various magnetic field conditions.

[0007] 2. When performing stress tests on different magnetorheological fluids, when the shear blade moves inside the magnetorheological fluid, it encounters a relatively large resistance. During the continuous force application process, it is extremely prone to deformation phenomena such as bending, twisting, and even fracture, which not only affects the accuracy and reliability of the test results but also requires frequent blade replacement, increasing the experimental cost and time cost and reducing the experimental efficiency.

[0008] 3. Traditional test experimental devices cannot perform real-time monitoring and spatial resolution on the microscopic motion state of particles inside magnetorheological fluids. Especially after applying a magnetic field, the dynamic behaviors of particles such as rapid aggregation and chain-like reconstruction in three-dimensional space are often in an "invisible" state. This limitation severely restricts the in-depth study of the microscopic structure evolution mechanism of magnetorheological fluids, particle response dynamics, and their correlation with macroscopic mechanical properties.

[0009] In view of this, we propose a rheological shear test experimental device based on in-situ CT imaging analysis. Summary of the Invention

[0010] The purpose of the present invention is to provide a rheological shear test experimental device based on in-situ CT imaging analysis to solve the problems proposed in the above background technology.

[0011] To achieve the above purpose, the present invention aims to provide a rheological shear test experimental device based on in-situ CT imaging analysis, including a CT scanner. Inside the CT scanner, there is a shear test bench. On the surface of the shear test bench, there is a liquid bucket. At the bottom of the liquid bucket, there is a heating sheet. On the inner wall of the liquid bucket, there are Hall elements. Above the shear test bench, there is a lifting frame that moves in the vertical direction. Inside the lifting frame, there is a servo motor. At the output end of the servo motor, there is a transmission shaft. Between the servo motor and the transmission shaft, there is an angular displacement sensor. At the bottom of the transmission shaft, there is a shear blade. At the bottom of the lifting frame, there is a U-shaped frame. Inside the U-shaped frame, there is a protection component. Inside the shear test bench, there is a groove, and inside the groove, there is a simulation component. The simulation component is used to simulate the influence of a complex stress environment on the magnetorheological fluid. The simulation component includes a rotating motor arranged in the groove. At the output end of the rotating motor, there is a main gear. Vertically meshed on the top of the main gear is a secondary gear. The secondary gears are arranged in a 90° circular array. At the end of the secondary gear, there is a lead screw. On the surface of the lead screw, there is a moving seat. On the surface of the moving seat, there is a sleeve. Inside the sleeve, there is an electromagnetic coil. On both sides of the moving seat, there is a limiting component. The limiting component is used to limit the moving sleeve.

[0012] As a further improvement of this technical solution, on both sides of the inner wall of the liquid bucket, there are Hall elements, and the Hall elements provide data for calculating the shear rate.

[0013] As a further improvement of the technical solution, an inner arc plate is provided at the top of the liquid storage bucket. The opening diameter of the inner arc plate is larger than the diameter of the shearing blade. When the shearing blade moves in the vertical direction, it can enter the interior of the liquid storage bucket through the inner arc plate. Magnets are provided on both sides of the bottom of the liquid storage bucket.

[0014] As a further improvement of the technical solution, temperature sensors are provided on the side walls of the U-shaped frame. The temperature sensors are symmetrically arranged, and the temperature sensors measure the temperature of the magnetorheological fluid in real time.

[0015] As a further improvement of the technical solution, the limiting component includes cylinder tubes provided on both sides of the surface of the moving seat. A sliding rod is slidably provided on the inner wall of the cylinder tube, and a compression spring is provided between the cylinder tube and the sliding rod.

[0016] As a further improvement of the technical solution, a clamping plate is provided at the end of the sliding rod. The clamping plate is arc-shaped and fits the outer wall of the sleeve.

[0017] As a further improvement of the technical solution, the threads on the surface of the lead screw are symmetrical. When the main gear rotates to drive the driven gear to mesh and rotate, the moving seat provided on the surface of the lead screw moves relative to its surface.

[0018] As a further improvement of the technical solution, the protection component includes a diversion plate provided in the U-shaped frame. The bottom of the diversion plate is in a conical state. Limiting rods are provided on both sides of the bottom of the diversion plate. The limiting rods slide on the bottom of the U-shaped frame, and a metal plate is provided at the bottom of the limiting rods. The metal plate is adsorbed when it approaches the magnet.

[0019] As a further improvement of the technical solution, a limiting rod is provided between the limiting rod and the U-shaped frame. In the natural state, the diversion plate is attached to the bottom of the shearing blade under the action of the elastic member.

[0020] As a further improvement of the technical solution, a PIV system is provided inside the CT instrument, and the movement trajectories of the tracer particles in the fluid are analyzed through the PIV system.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. In the rheological shear test experimental device based on in-situ CT imaging analysis, during the test, the bottom of the liquid storage bucket is heated by the heating sheet, and the temperature inside the liquid storage bucket is monitored in real time through the temperature sensor, so that the temperature in the liquid storage bucket always remains stable during the test, avoiding the change of the movement ability of the internal molecular chains and the intermolecular interaction force in the magnetorheological fluid with temperature change, thereby keeping its rheological properties stable and improving the accuracy of data during the rheological shear test.

[0023] 2. In the rheological shear test experimental device based on in-situ CT imaging analysis, the main gear is driven to rotate by controlling the output shaft of the rotating motor. When the main gear rotates, it drives the sub-gear to mesh and rotate. The sub-gear drives the lead screw to rotate coaxially. The movable seat provided on the surface of the lead screw moves relatively. Since a sleeve is provided on the surface of the movable seat, the electromagnetic coil provided inside the sleeve is controlled to be turned on and off, thereby changing the magnetic field around the liquid barrel, simulating a complex stress environment, so that the material ratio can be adjusted in a targeted manner, or the preparation process can be improved, thereby improving the tolerance and reliability of the material under complex working conditions.

[0024] 3. In the rheological shear test experimental device based on in-situ CT imaging analysis, the lifting frame is controlled to move downward in the vertical direction. During the movement, the guide plate contacts the magnetorheological fluid. Since the bottom of the guide plate is conical, the resistance during the movement of the guide plate can be reduced. Since the guide plate fits with the bottom of the shear blade during movement, the deformation of the shear blade caused by excessive resistance during movement is avoided, thereby improving the service life of the shear blade.

[0025] 4. In this rheological shear test experimental device based on in-situ CT imaging analysis, a multi-scale, multi-dimensional visualization observation system is constructed by integrating X-ray computed tomography (CT) two-dimensional projection technology and particle image velocimetry (PIV) method. Among them, the CT two-dimensional imaging of the CT instrument can provide the density distribution and structural configuration changes of the particle group within a specific cross-section, while the PIV technology realizes the quantitative calculation of the particle velocity field by tracking the flow field displacement of the labeled particles. The combination of the two can not only realize high-resolution observation of the movement behavior of particles in magnetorheological fluid under the synergistic action of shear and magnetic field, but also reveal the spatiotemporal characteristics of its particle reconstruction and chain structure growth, providing key technical support for in-depth understanding of the relationship between rheological behavior and structural response under magnetic field regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 Schematic diagram of the overall structure of the shear test bench of the present invention;

[0028] Figure 3 is a cross-sectional view of the shear test bench of the present invention;

[0029] Figure 4 It is a cross-sectional view of the liquid storage barrel of the present invention;

[0030] Figure 5 This is a schematic diagram of the lifting frame structure of the present invention;

[0031] Figure 6 It is a schematic diagram of the structure of the simulation component of the present invention;

[0032] Figure 7 Cross-sectional view of the limit component of the present invention;

[0033] Figure 8 Schematic structural diagram of the protection component of the present invention.

[0034] The meanings of the labels in the figure are as follows:

[0035] 100, CT scanner;

[0036] 200, Shearing test bench; 201, Liquid storage bucket; 202, Hall element; 203, Magnet; 204, Inner arc plate; 205, Lifting frame; 206, Servo motor; 207, Angular displacement sensor; 208, Transmission shaft; 209, Shearing blade; 210, U-shaped frame; 211, Temperature sensor; 212, Heating element;

[0037] 300, Simulation component; 301, Rotating motor; 302, Main gear; 303, Sub-gear; 304, Lead screw; 305, Moving seat; 306, Sleeve; 307, Electromagnetic coil;

[0038] 400, Limit component; 401, Cylindrical tube; 402, Slide bar; 403, Compression spring; 404, Clamping plate;

[0039] 500, Protection component; 501, Deflector; 502, Limit rod; 503, Metal plate; 504, Elastic member. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0042] The purpose of this embodiment is to provide a rheological shear test experimental device based on in-situ CT imaging analysis. Refer toFigures 1-8 As shown in the figure, it includes a CT instrument 100. Inside the CT instrument 100, there is a shear test bench 200. On the surface of the shear test bench 200, there is a liquid storage bucket 201. At the bottom of the liquid storage bucket 201, there is a heating sheet 212. On the inner wall of the liquid storage bucket 201, there is a Hall element 202. Above the shear test bench 200, there is a lifting frame 205. The lifting frame 205 moves in the vertical direction. Inside the lifting frame 205, there is a servo motor 206. At the output end of the servo motor 206, there is a transmission shaft 208. Between the servo motor 206 and the transmission shaft 208, there is an angular displacement sensor 207. At the bottom of the transmission shaft 208, there is a shear blade 209. At the bottom of the lifting frame 205, there is a U-shaped frame 210. Inside the U-shaped frame 210, there is a protection component 500. Inside the shear test bench 200, there is a groove. Inside the groove, there is a simulation component 300. The simulation component 300 is used to simulate the influence of a complex stress environment on the magnetorheological fluid. The simulation component 300 includes a rotating motor 301 arranged in the groove. At the output end of the rotating motor 301, there is a main gear 302. Vertically meshed at the top of the main gear 302, there is a secondary gear 303. The secondary gears 303 are arranged in a 90° circular array. At the end of the secondary gear 303, there is a lead screw 304. On the surface of the lead screw 304, there is a moving seat 305. On the surface of the moving seat 305, there is a sleeve 306. Inside the sleeve 306, there is an electromagnetic coil 307. On both sides of the moving seat 305, there is a limiting component 400. The limiting component 400 is used to limit the moving sleeve 306.

[0043] The CT instrument 100 can obtain a series of high-resolution two-dimensional tomographic images by performing multi-angle X-ray scans on the sample. During the shear test process, it is like "layer by layer dissecting" the sample, clearly presenting the dynamic changes in the internal structure of test samples such as magnetorheological fluid and composite materials under the action of shear force. For example, in the magnetorheological fluid test, the two-dimensional image can intuitively show the process of magnetic particles changing from uniform dispersion to forming chain-like and columnar structures under an external magnetic field, accurately capturing details such as particle aggregation and orientation changes; for composite materials containing fibers or fillers, the dislocation and bending of fibers under shear force, as well as the interfacial separation phenomenon between the filler and the matrix can be observed. These two-dimensional images provide an intuitive and accurate data basis for studying the evolution of the material's microstructure, helping scientific researchers understand the essential reasons for the changes in the macroscopic rheological properties of the material; the cooperation with the CT instrument 100 during the rheological shear test provides direct evidence for understanding the essential reasons for the changes in the macroscopic rheological properties of the material.

[0044] During the rheological shear test, in order to facilitate the acquisition of accurate shear force data, Hall plates 202 are provided on both sides of the inner wall of the liquid storage barrel 201. The Hall plates 202 provide data for calculating the shear rate. Through the Hall plates 202, the angular displacement and movement speed of the component can be measured in real time and accurately, and converted into electrical signals and transmitted to the data acquisition and analysis system. Compared with the traditional monitoring method, the non-contact measurement characteristic of the Hall plates 202 avoids wear and measurement errors caused by mechanical contact, and can obtain the real-time motion state of the shear loading system more accurately, so as to provide more reliable data for calculating the shear displacement and shear rate of the sample, and further improve the accuracy of the material rheological property test. At the same time, during the shear process, the internal structure of the sample is scanned in real time by the CT instrument 100 to obtain image data. The combination of the high-precision shear loading system and the high-resolution in-situ CT imaging system ensures the accuracy and reliability of the test data.

[0045] A rheological observation device with adjustable shear rate and magnetic field intensity is designed, which is equipped with a high-precision CT scanning system and a high-speed camera to realize synchronous imaging and velocity field capture of the sample under different loading conditions. This method not only breaks through the spatial resolution bottleneck of traditional rheological testing methods, but also provides a new research paradigm for the visualization analysis of the complex behavior of multiphase fluids.

[0046] During the test, in order to prevent the magnetorheological fluid from splashing out, an inner arc plate 204 is provided at the top of the liquid storage barrel 201. The opening diameter of the inner arc plate 204 is larger than the diameter of the shear blade 209. When the shear blade 209 moves vertically, it can enter the inside of the liquid storage barrel 201 through the inner arc plate 204. Magnets 203 are provided on both sides of the bottom of the liquid storage barrel 201. During the shear experiment, the lifting frame 205 is controlled to drive the shear blade 209 to move downward vertically. When the shear blade 209 moves from the opening of the inner arc plate 204 to the inside of the liquid storage barrel 201, the output shaft of the servo motor 206 is controlled to drive the transmission shaft 208 to rotate. The shear blade 209 provided at the bottom of the transmission shaft 208 obtains experimental data during rotation. By setting the inner arc plate 204 at the top of the liquid storage barrel 201, the splashing magnetorheological fluid is blocked by the inner arc plate 204 to prevent it from overflowing and avoid the pollution of the shear test bench 200 by the magnetorheological fluid during the experiment.

[0047] When using the experimental device to test shear force, in order to ensure the accuracy, reliability and comparability of the experimental results and avoid temperature factors interfering with the analysis of the rheological properties of the material, temperature sensors 211 are provided on the side walls of the U-shaped frame 210. The temperature sensors 211 are symmetrically arranged and measure the temperature of the magnetorheological fluid in real time. During the test, the bottom of the liquid barrel 201 is heated by the heating plate 212, and the temperature inside the liquid barrel 201 is monitored in real time by the temperature sensor 211, so that the temperature inside the liquid barrel 201 remains stable during the test, avoiding the movement ability of the molecular chains inside the magnetorheological fluid and the interaction force between molecules from changing with temperature, thereby keeping its rheological properties stable and improving the accuracy of the data during the rheological shear test.

[0048] During the rheological shear test, in order to simulate a complex stress environment and optimize the material design, the simulation component 300 includes a rotating motor 301 arranged in a groove, a main gear 302 is provided at the output end of the rotating motor 301, and a sub-gear 303 is provided at the top of the main gear 302 in vertical meshing. The sub-gears 303 are arranged in a 90° ring. A screw rod 304 is provided at the end of the sub-gear 303, a movable seat 305 is provided on the surface of the screw rod 304, a sleeve 306 is provided on the surface of the movable seat 305, and an electromagnetic coil 307 is provided inside the sleeve 306. The main gear 302 is driven to rotate by controlling the output shaft of the rotating motor 301, and the sub-gear 303 is driven to mesh when the main gear 302 rotates. When the main gear 302 rotates, the secondary gear 303 drives the screw rod 304 to rotate coaxially, and the moving seat 305 provided on the surface of the screw rod 304 moves relatively. The thread on the surface of the screw rod 304 is symmetrical. When the main gear 302 rotates and drives the secondary gear 303 to mesh and rotate, the moving seat 305 provided on the surface of the screw rod 304 moves relatively on its surface. Since a sleeve 306 is provided on the surface of the moving seat 305, the electromagnetic coil 307 provided inside the sleeve 306 is controlled to be turned on and off, thereby changing the magnetic field around the liquid storage barrel 201, simulating a complex stress environment, so as to be able to adjust the material ratio in a targeted manner, or improve the preparation process, and improve the tolerance and reliability of the material under complex working conditions;

[0049] At the same time, by establishing a complex stress environment, the microstructural changes and macroscopic mechanical responses within the material are more complex. By combining the CT instrument 100, when simulating complex stress, the evolution of the material's internal structure under the action of multiple force couplings can be observed in real time, such as crack initiation and propagation paths, as well as changes in the material's internal phase state. This helps researchers conduct in-depth research on the failure mechanism of materials under complex stress and provides a theoretical basis for the optimization design and improvement of materials.

[0050] When the control electromagnetic coil 307 moves relatively to simulate a complex stress environment, in order to prevent the sleeve 306 from tipping due to inertia during the movement, therefore, the limiting component 400 includes cylinder barrels 401 provided on both sides of the surface of the moving seat 305. A sliding rod 402 is slidably provided on the inner wall of the cylinder barrel 401. A compression spring 403 is provided between the cylinder barrel 401 and the sliding rod 402. A clamping plate 404 is provided at the end of the sliding rod 402. The clamping plate 404 is arc-shaped and fits against the outer wall of the sleeve 306. When installing and placing the sleeve 306, by squeezing the clamping plate 404, the sliding rod 402 provided at the end of the clamping plate 404 slides on the inner wall of the cylinder barrel 401, so that the diameter between the clamping plates 404 increases. The sleeve 306 is placed on the surface of the moving seat 305. Stop pressing the clamping plate 404. The sliding rod 402 is subjected to the restoring force of the compression spring 403, so that the clamping plates 404 move relative to each other, thereby squeezing and limiting the bottom of the sleeve 306. When adjusting the position of the sleeve 306 to simulate the adhesion stress, the stability of the sleeve 306 is ensured.

[0051] During the shear force test of the magnetorheological fluid, since the thickness of the shear blade 209 is relatively thin, when the bottom of the shear blade 209 contacts the surface of the magnetorheological fluid, when the concentration of the magnetorheological fluid is different, it may cause the shear blade 209 to deform due to excessive reaction force when it moves to the surface and descends. Therefore, the protection component 500 includes a diversion plate 501 provided in the U-shaped frame 210. Limiting rods 502 are provided on both sides of the bottom of the diversion plate 501. The limiting rods 502 slide on the bottom of the U-shaped frame 210. A metal plate 503 is provided at the bottom of the limiting rod 502. The metal plate 503 is adsorbed when approaching the magnet 203. A limiting rod 502 is provided between the limiting rod 502 and the U-shaped frame 210. In the natural state, the diversion plate 501 is attached to the bottom of the shear blade 209 under the action of the elastic member 504. The bottom of the diversion plate 501 is in a conical state. The diversion plate 501 reduces the resistance when moving in the magnetorheological fluid. During the test, by controlling the lifting frame 205 to move downward in the vertical direction, the diversion plate 501 contacts the magnetorheological fluid during the movement. Since the bottom of the diversion plate 501 is conical, the resistance during the movement of the diversion plate 501 can be reduced. Since the diversion plate 501 is attached to the bottom of the shear blade 209 during the movement, the shear blade 209 is prevented from deforming due to excessive resistance during the movement, and the service life of the shear blade 209 is improved. When the diversion plate 501 moves to be close to the bottom of the liquid storage bucket 201, the metal plate 503 is attracted by the suction force of the magnet 203, so that the limiting rod 502 drives the diversion plate 501 to move downward in the vertical direction and away from the shear blade 209, thereby ensuring the accuracy of the test.

[0052] The PIV (Particle Image Velocimetry) system is provided inside the CT instrument 100. The movement trajectories of tracer particles in the fluid are analyzed through the PIV system. Among them, the PIV system generally includes the following parts:

[0053] Light source system: Generally composed of a double-cavity pulsed laser, a light guiding arm, and a sheet light source lens group. The double-cavity pulsed laser can emit high-energy, short-pulse lasers, providing sufficient illumination intensity for the tracer particles in the flow field so as to clearly capture the particle images;

[0054] Image acquisition system: Mainly includes a high-resolution cross-frame CCD camera and a 64-bit dedicated high-speed image data acquisition board. The high-resolution cross-frame CCD camera can quickly capture the images of tracer particles, featuring high frame rate and high resolution, and can record the position information of particles at different moments in an extremely short time;

[0055] Control and coordination system: Usually served by a synchronizer. The role of the synchronizer is to precisely control the pulse emission time of the laser and the shooting time of the camera, enabling the two to work synchronously. Through the coordination of the synchronizer, it is ensured that at the moment when the laser illuminates the flow field, the camera can accurately capture the particle images, thus realizing the precise measurement of particle motion;

[0056] PIV image data processing and flow field display system: Such as the Insight software package and its external interface. This system is used to process and analyze the collected particle images, calculate the displacement and velocity information of the particles through specific algorithms, and then obtain the velocity vector distribution of the flow field. At the same time, it can also display the processed data in an intuitive way, such as drawing velocity vector diagrams, streamline diagrams, etc., facilitating researchers to observe and analyze the characteristics of the flow field;

[0057] Verify the accuracy of the interpretation of the "particle motion trajectory" in the CT image through the velocity field data of PIV, or correct the uniform distribution of PIV tracer particles using the density distribution of CT, thereby improving the reliability of multi-source data.

[0058] When using X-ray CT to conduct structural visualization research on magnetorheological fluid (MRF), in addition to the high absorption characteristics of the sample itself, the selection of container materials also has a significant impact on imaging penetrability and image quality;

[0059] The container needs to meet two basic conditions: First, the material should have as low X-ray absorption as possible to improve the imaging penetration rate and signal-to-noise ratio; Second, the container needs to have certain chemical stability and mechanical strength to withstand the dynamic response of the magnetorheological fluid under shear and magnetic field actions. After comprehensive consideration, the commonly used low-absorption, high-transmission materials include:

[0060] Polymethyl methacrylate (PMMA, acrylic): Good X-ray penetrability, few imaging artifacts, easy to process into an observation window, suitable for low-pressure and low-speed conditions;

[0061] Polycarbonate: It has good transmission performance and better mechanical properties than PMMA, and is suitable for medium shear rate and weak magnetic field environments;

[0062] Polyimide film: It has controllable thickness, strong flexibility and extremely high transmittance, and is often used for the encapsulation of microchannel devices;

[0063] Borosilicate glass: Although its absorption rate is slightly higher, it performs well in high temperature and solvent resistance, and can be used in the design of samples compatible with corrosion. A trade-off is needed when using it.

[0064] In the construction of specific devices, a detachable polymer observation window and magnetic field loading module decoupling design is often adopted to avoid the interference of the container on the magnetic field. At the same time, it is ensured that the imaging window area has a uniform thickness to reduce edge effects. Some studies also adopt a heterogeneous structure design, that is, on the premise of keeping the core observation area as a high-transparency material, a rigid material is used on the periphery to provide mechanical support, so as to achieve a balance between image quality and device stability;

[0065] In summary, the reasonable selection of container materials and structural design is one of the key steps to achieve high-quality CT imaging. In the future, the customization of containers combining micro 3D printing technology and low-absorption composite materials will further promote the in-depth development of magnetorheological fluids in the direction of visualization rheology.

[0066] During specific use, the lifting frame 205 is controlled to drive the shear blade 209 to move downward vertically. When the shear blade 209 moves from the opening of the inner arc plate 204 to the inside of the liquid storage barrel 201, the output shaft of the servo motor 206 is controlled to drive the transmission shaft 208 to rotate. The shear blade 209 provided at the bottom of the transmission shaft 208 obtains experimental data during the rotation process. By setting the inner arc plate 204 at the top of the liquid storage barrel 201, the splashing magnetorheological fluid is blocked by the inner arc plate 204 to prevent it from overflowing and avoid the pollution of the shear test bench 200 by the magnetorheological fluid during the experiment;

[0067] The angular displacement and movement speed of the component can be measured in real time and accurately through the Hall chip 202, and converted into electrical signals and transmitted to the data acquisition and analysis system. Compared with the traditional monitoring method, the non-contact measurement characteristic of the Hall chip 202 avoids the wear and measurement errors caused by mechanical contact, and can obtain the real-time motion state of the shear loading system more accurately, so as to provide more reliable data for calculating the shear displacement and shear rate of the sample, and further improve the accuracy of material rheological property testing;

[0068] During the test, the bottom of the liquid storage barrel 201 is heated by the heating sheet 212, and the temperature inside the liquid storage barrel 201 is monitored in real time through the temperature sensor 211 to keep the temperature inside the liquid storage barrel 201 stable during the test;

[0069] By controlling the output shaft of the rotating motor 301 to drive the main gear 302 to rotate, when the main gear 302 rotates, it drives the driven gear 303 to mesh and rotate. The driven gear 303 drives the lead screw 304 to rotate coaxially. The moving seat 305 provided on the surface of the lead screw 304 moves relatively. The thread on the surface of the lead screw 304 is symmetric. When the main gear 302 rotates and drives the driven gear 303 to mesh and rotate, the moving seat 305 provided on the surface of the lead screw 304 moves relatively on its surface. Since the sleeve 306 is provided on the surface of the moving seat 305, by controlling the on-off of the electromagnetic coil 307 provided inside the sleeve 306, the magnetic field around the liquid storage bucket 201 is changed to simulate a complex stress environment, so that the material ratio can be adjusted targeted, or the preparation process can be improved to improve the tolerance and reliability of the material under complex working conditions;

[0070] By controlling the lifting frame 205 to move downward in the vertical direction, during the movement, the deflector 501 contacts the magnetorheological fluid. Since the bottom of the deflector 501 is conical, the resistance during the movement of the deflector 501 can be reduced. Since the deflector 501 fits with the bottom of the shear blade 209 during the movement, the deformation of the blade of the shear blade 209 caused by excessive resistance during the movement is avoided, and the service life of the shear blade 209 is improved. When the deflector 501 moves to near the bottom of the liquid storage bucket 201, the metal plate 503 is attracted by the magnet 203, so that the limiting rod 502 drives the deflector 501 to move downward in the vertical direction and away from the shear blade 209, thus ensuring the accuracy of the test.

[0071] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A rheological shear test experimental device based on in-situ CT imaging analysis, characterized in that: It includes a CT scanner (100). Inside the CT scanner (100), there is a shear test bench (200). On the surface of the shear test bench (200), there is a liquid storage bucket (201). At the bottom of the liquid storage bucket (201), there is a heating sheet (212). On the inner wall of the liquid storage bucket (201), there is a Hall element (202). Above the shear test bench (200), there is a lifting frame (205). The lifting frame (205) moves in the vertical direction. Inside the lifting frame (205), there is a servo motor (206). At the output end of the servo motor (206), there is a transmission shaft (208). Between the servo motor (206) and the transmission shaft (208), there is an angular displacement sensor (207). At the bottom of the transmission shaft (208), there is a shear blade (209). At the bottom of the lifting frame (205), there is a U-shaped frame (210). Inside the U-shaped frame (210), there is a protection component (500). Inside the shear test bench (200), there is a groove, and inside the groove, there is a simulation component (300). The simulation component (300) is used to simulate the influence of a complex stress environment on magnetorheological fluid. The simulation component (300) includes a rotation motor (301) arranged in the groove. At the output end of the rotation motor (301), there is a main gear (302). Vertically meshed on the top of the main gear (302), there is a secondary gear (303). The secondary gears (303) are arranged in a 90° annular array. At the end of the secondary gear (303), there is a lead screw (304). On the surface of the lead screw (304), there is a moving seat (305). On the surface of the moving seat (305), there is a sleeve (306). Inside the sleeve (306), there is an electromagnetic coil (307). On both sides of the moving seat (305), there is a limit component (400). The limit component (400) is used to limit the moving sleeve (306).

2. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 1, wherein: On both sides of the inner wall of the liquid storage bucket (201), there are Hall elements (202). The Hall elements (202) provide data for calculating the shear rate.

3. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 2, wherein: On the top of the liquid storage bucket (201), there is an inner arc plate (204). The opening diameter of the inner arc plate (204) is larger than the diameter of the shear blade (209). When the shear blade (209) moves in the vertical direction, it can enter the inside of the liquid storage bucket (201) through the inner arc plate (204). On both sides of the bottom of the liquid storage bucket (201), there are magnets (203).

4. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 1, characterized in that: On the side walls of the U-shaped frame (210), there are temperature sensors (211). The temperature sensors (211) are symmetrically arranged. The temperature sensors (211) measure the temperature of the magnetorheological fluid in real time.

5. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 1, wherein: The limit component (400) includes cylinder barrels (401) arranged on both sides of the surface of the moving seat (305). Inside the inner wall of the cylinder barrels (401), there are sliding rods (402). Between the cylinder barrels (401) and the sliding rods (402), there are compression springs (403).

6. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 5, wherein: At the end of the sliding rod (402), there is a clamping plate (404). The clamping plate (404) is arc-shaped and fits the outer wall of the sleeve (306).

7. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 1, characterized in that: The surface thread of the lead screw (304) is symmetric. When the main gear (302) rotates to drive the driven gear (303) to mesh and rotate, the moving seat (305) provided on the surface of the lead screw (304) moves relative to its surface.

8. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 1, wherein: The protection component (500) includes a flow deflector (501). The bottom of the flow deflector (501) is in a conical state. Limiting rods (502) are provided on both sides of the bottom of the flow deflector (501). The limiting rods (502) slide on the bottom of the U-shaped frame (210). A metal plate (503) is provided at the bottom of the limiting rod (502). The metal plate (503) is adsorbed when approaching the magnet (203).

9. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 8, wherein: A limiting rod (502) is provided between the limiting rod (502) and the U-shaped frame (210). In the natural state, the flow deflector (501) is attached to the bottom of the shear blade (209) under the action of the elastic member (504).

10. The rheological shear test experimental device based on in-situ CT imaging analysis according to claim 8, characterized in that: A PIV system is provided inside the CT scanner (100). The motion trajectory of the tracer particles in the fluid is analyzed through the PIV system.

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