Fluid-structure interaction parameter visualization mechanical experiment device

Abstract

The invention belongs to the technical field of particulate matter mechanical property testing, and particularly discloses a fluid-solid coupling parameter visualization mechanical experiment device which comprises a stress loading mechanism, a parameter visualization mechanism and a parameter visualization mechanism, and the stress loading mechanism is provided with an experiment platform and a plurality of load applying ends; the loading part is arranged in the center of the experiment platform; a loading cavity for accommodating an experimental object is formed in the loading part, and the load applying end extends to the loading cavity from the outside of the loading part; a water guide channel is formed in the side part of the loading part along a conducting direction; the water guide channel communicates with the loading cavity; the movement direction of the load applying end is the same as the conduction direction; the monitoring part is provided with a transmitting end and a receiving end; the transmitting end transmits a monitoring signal along a propagation direction; the device has the following advantages that various stresses are achieved through the multiple load applying ends, fluid-solid coupling is achieved by adjusting water pressure through the water guide channel, the monitoring part obtains structural changes in real time through photoelastic stripes, the experiment flexibility is improved, the real working condition and the data accuracy are simulated, and diversified mechanical research requirements are met.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical property testing of granular materials, and in particular to a parameter visualization mechanical experimental device for fluid-solid coupling. Background Art

[0002] The soil is composed of three phases: solid particles, liquid and gas. When water or other fluids flow in the gaps between soil particles, they will cause extremely complex mechanical behaviors with multi-scale characteristics. At the macroscopic scale, this kind of mechanical behavior is deeply affected by the microscopic structural characteristics. Therefore, the study of the microscopic scale can not only help to deeply understand the essential mechanism of macroscopic mechanical properties, but also provide a scientific basis for related engineering design and academic research. Although the existing photoelastic experimental technology has some implications in analyzing the stress distribution and deformation law of solid materials, it is difficult to provide an effective experimental environment for the coexistence of solid, liquid and gas such as soil because it can usually only be tested under the condition of a single solid phase. Therefore, it is impossible to achieve in-depth research on the coupling between particles and fluid flow. In addition, in terms of the lateral load application method, the current experimental device mostly adopts a simple mode of rigid plate overall pressurization. The load action form is single and it is not easy to flexibly simulate complex stress fields, or it is difficult to achieve precise control of the load even if flexible pressurization means are used. These technical limitations make it difficult for existing studies to simultaneously examine the real mechanical characteristics of soil particles and fluids at the microscopic and macroscopic levels, thus affecting the accurate understanding and analysis of the internal mechanism of soil mechanical behavior.

[0003] Therefore, a parameter visualization mechanics experimental device of fluid-solid coupling is proposed to solve the above problems. Summary of the invention

[0004] The present invention aims to provide a fluid-solid coupling parameter visualization mechanical experimental device to solve or improve the above-mentioned technical problem that the existing photoelastic experimental technology cannot effectively study the complex mechanical behavior of the interaction between fluid flow and particles in soil.

[0005] In view of this, a first aspect of the present invention is to provide a fluid-solid coupling parameter visualization mechanics experimental device.

[0006] The first aspect of the present invention provides a parameter visualization mechanics experimental device for fluid-solid coupling, comprising: a stress loading mechanism, which has an experimental platform and a plurality of load applying ends; the load applying ends are arranged circumferentially on the experimental platform, and each of the load applying ends can move independently to form a variety of stress states in the center of the experimental platform; the movement direction of each of the load applying ends is a uniaxial direction, and all the movement directions are located in a plane of the experimental platform; a loading part is arranged in the center of the experimental platform; the interior of the loading part has a loading cavity for accommodating an experimental object, and the load applying end is moved from the outside of the loading part A portion extends to the loading chamber; a water guide channel is opened at the side of the loading portion along a conduction direction; the water guide channel is connected to the loading chamber, and the water guide channel injects and / or extracts the experimental water from the experimental object through the loading chamber; the movement direction of at least one of the load applying ends is the same as the conduction direction; a monitoring portion, which has a transmitting end and a receiving end; the transmitting end transmits a monitoring signal along a propagation direction, and the conduction direction and the propagation direction intersect at the middle of the loading chamber; the monitoring signal enters the receiving end after passing through the experimental object, and obtains the structural morphology corresponding to the experimental object under the current stress state.

[0007] In any of the above technical solutions, the parameter visualization mechanics experimental device also includes: at least one flexible block, and the flexible block is connected to the load application end; before the load application end moves, the side wall of the flexible block adheres to the experimental object.

[0008] In any of the above technical solutions, the flexible block is connected to the load applying end via a buffer mechanism to maintain the position of the flexible block in the loading cavity when the load applying end moves.

[0009] In any of the above technical solutions, the buffer mechanism includes: a first rod body, which is connected to the load application end along the movement direction, and the first rod body is hollow; the side wall of the flexible block is connected to the end face of the first rod body through a spring; a second rod body, which is concentrically arranged with the first rod body, and the second rod body and the first rod body can move relative to each other along the movement direction; one end of the second rod body is connected to the flexible block, and the other end of the second rod body is detachably assembled on the experimental platform.

[0010] In any of the above technical solutions, the circumferential side wall of the second rod body located outside the first rod body is sleeved with the spring, and pressure sensors are respectively provided at the connection between the spring and the flexible block and inside the water guiding channel; the stress state includes the water pressure value of the experimental water and the pressure value acting on each of the flexible blocks.

[0011] In any of the above technical solutions, when the experimental object is in the stress state, the following situations occur: situation one, closing the water channel and maintaining the experimental water volume in the loading chamber to adjust the water pressure value; situation two, opening the water channel and changing the experimental water volume in the loading chamber to adjust the pressure value.

[0012] In any of the above technical solutions, at least one buffer mechanism is provided on the same load applying end, and the elastic coefficients of all springs corresponding to the same load applying end are the same or different.

[0013] In any of the above technical solutions, the experimental object includes a plurality of reflective particles, and water-conducting gaps are formed between the reflective particles; and the flexible block corresponds to the plurality of reflective particles along the movement direction.

[0014] In any of the above technical solutions, the loading part is made of light-transmitting material, and the monitoring signal includes a light signal; the structural form acquired by the light signal is photoelastic stripes, and the image data of the photoelastic stripes is used as the output of the parameter visualization mechanics experimental device.

[0015] In any of the above technical solutions, the loading portion is located between the transmitting end and the receiving end, and the propagation direction is set in the same direction as the normal direction of the plane.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] By arranging multiple load application ends along the circumference of the experimental platform and each load application end can move independently, a variety of complex stress states can be formed in the central area at the same time, which not only improves the flexibility and diversity of stress application, but also can simulate a more realistic and complex mechanical environment to meet different experimental needs.

[0018] The loading part is equipped with a water channel, which can adjust the water pressure in the loading chamber by injecting and extracting experimental water, realizing the dynamic coupling of fluid and solid materials. It can simulate the influence of fluid on soil or other granular materials in actual engineering, such as the mechanical behavior under complex working conditions such as earthquake, wind load or water flow impact, and provide a real and reliable experimental environment for fluid-solid coupling mechanics research.

[0019] The monitoring unit is equipped with a transmitter and a receiver. By emitting plane polarized light and forming a circular polarization field in the loading cavity, the photoelastic stripe technology is used to obtain the structural morphological changes of the experimental object under different stress states in real time. The image data of the photoelastic stripe is output as a parameter visualization, allowing researchers to observe and analyze the stress distribution, deformation and internal mechanical behavior of the experimental object intuitively and in real time, improving the efficiency and accuracy of data acquisition.

[0020] Additional aspects and advantages of embodiments according to the present invention will become apparent in the following description or may be learned through practice of embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the visual loading mechanism and its connection structure of the present invention;

[0024] Figure 3 A partial schematic diagram of the visual loading mechanism of the present invention;

[0025] Figure 4 Another partial schematic diagram of the visual loading mechanism of the present invention;

[0026] Figure 5 is another partial schematic diagram of the visual loading mechanism of the present invention,

[0027] in, Figure 1-Figure 5 The corresponding relationship between the reference numerals and the component names is as follows:

[0028] 1 lower bracket, 2 stress loading mechanism, 3 upper bracket, 4 lateral load applying mechanism, 401 first stepping motor, 402 second stepping motor, 403 central bearing, 404 upper clamping plate, 405 lower clamping plate, 406 frame plate, 407 push rod, 408 front push plate, 409 rear push plate, 410 second rod body, 411 first rod body, 412 flexible block, 413 spring, 414 truncated cone block, 5 axial load applying mechanism, 501 third stepping motor, 502 loading plate, 6 support plate, 7 transparent water tank plate, 701 injection channel, 702 drainage channel. DETAILED DESCRIPTION

[0029] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0031] See also Figure 1-Figure 5, a parameter visualization mechanics experimental device for fluid-solid coupling according to some embodiments of the present invention is described below.

[0032] The embodiment of the first aspect of the present invention provides a parameter visualization mechanical experimental device for fluid-solid coupling. In some embodiments of the present invention, Figure 1-Figure 5 As shown, the parameter visualization mechanics experimental device includes:

[0033] The stress loading mechanism 2 has an experimental platform and a plurality of load applying ends; the load applying ends are arranged circumferentially on the experimental platform, and each load applying end can move and apply a load independently, and multiple stress states are formed by applying multiple loads and adjusting them separately in the center of the experimental platform; the movement direction of each load applying end is a uniaxial direction, and all movement directions are located in a plane of the experimental platform.

[0034] The loading part is arranged in the center of the experimental platform; the loading part has a loading cavity for accommodating the experimental object inside, and the load applying end extends from the outside of the loading part to the loading cavity to apply a load to the experimental object; a water conducting channel is opened on the side of the loading part along a conducting direction; the water conducting channel is connected to the loading cavity, and the water conducting channel injects experimental water into and / or extracts experimental water from the experimental object through the loading cavity; the movement direction of at least one load applying end is the same as the conducting direction.

[0035] The monitoring part has a transmitting end and a receiving end; the transmitting end transmits a monitoring signal along a propagation direction, and the conduction direction and the propagation direction intersect at the middle of the loading cavity; the monitoring signal enters the receiving end after passing through the experimental object, and obtains the corresponding structural form of the experimental object under the current stress state.

[0036] The present invention provides a parameter visualization mechanics experimental device for fluid-solid coupling, wherein the stress loading mechanism 2 includes an experimental platform and a plurality of load applying ends. The experimental platform is made of high-strength, low-vibration materials to ensure that the platform itself will not be significantly deformed or displaced when multi-directional loads are applied, thereby ensuring the accuracy and repeatability of the experimental data. The experimental platform is designed as a transparent or translucent structure to facilitate real-time observation of the interaction between fluid and solid particles, meeting the special needs of fluid-solid coupling research. The plurality of load applying ends in the stress loading mechanism 2 are evenly arranged along the circumference of the experimental platform, and each load applying end is equipped with an independent drive device and control system, which can move and apply loads independently. This arrangement ensures that the load can be evenly distributed in all directions, providing a flexible experimental environment for simulating different stress states.

[0037] Multiple load application ends are evenly arranged along the circumference of the experimental platform to ensure balanced distribution of loads in all directions. Each load application end is equipped with an independent drive device and control system, which can move and apply loads independently. This design allows each load application end to independently adjust the magnitude, direction and application time of the applied force according to the experimental requirements, thereby simulating different stress states. For example, in the soil fluid-solid coupling experiment, pressures in different directions can be applied through different load application ends to simulate various working conditions such as earthquakes, wind loads or water flow impacts that may be encountered in actual engineering. The independence of multiple load application ends combined with the circumferential layout enables the experimental device to apply loads of different directions and sizes in the same experimental process, forming a variety of complex stress states. This design not only improves the flexibility and adaptability of the experiment, but also enhances the diversity and reliability of the experimental results, providing a solid experimental foundation for in-depth research on the fluid-solid coupling mechanism.

[0038] The movement direction of each load application end is uniaxial, and the movement directions of all load application ends are in the same plane of the experimental platform. This design not only simplifies the complexity of load control, but also ensures the directionality and controllability of load application. The uniaxial movement direction makes the application process of each load application end more accurate and predictable, avoiding the complexity and potential instability caused by the superposition of multi-directional loads. The design of the uniaxial movement direction enables the load application ends to work together in the same plane to form a balanced and controllable stress field. This provides a stable and repeatable experimental environment for studying the complex mechanical behavior of solid particles, liquid and gas in soil under the three-phase coupling. In addition, the layout of the movement direction in the same plane ensures the symmetry and coordination of load application, allowing each load application end to work together during the experiment, further improving the accuracy and reliability of the experimental data.

[0039] The loading part is located in the center of the experimental platform and is the core component of the entire experimental device. The loading part is designed with a loading cavity for accommodating the experimental object. The loading cavity is specially used to place and fix the material samples to be tested, such as soil particles or other multiphase medium materials. The design of the loading cavity ensures that the experimental object can remain stable under the action of force and fluid, avoiding displacement or deformation during the experiment, thereby improving the accuracy and repeatability of the experimental data. The structure of the loading cavity is usually made of transparent materials, which is convenient for real-time monitoring of the internal state changes of the experimental object through a visualization system.

[0040] The load application end extends from the outside of the loading part to the loading cavity, and its main function is to apply load to the test object. Each load application end is equipped with an independent drive device and control system, which can move and apply load independently. This design allows each load application end to independently adjust the magnitude, direction and application time of the applied force according to the experimental requirements, thereby simulating different stress states. For example, when conducting a soil fluid-solid coupling experiment, pressure in different directions can be applied through different load application ends to simulate various actual working conditions such as earthquakes, wind loads or water flow impacts. This multi-load application design not only improves the flexibility and adaptability of the experiment, but also can more comprehensively simulate and analyze the mechanical behavior of materials under complex stress conditions.

[0041] Along a conduction direction, a water channel is opened on the side of the loading part. The water channel is connected to the loading chamber, and the experimental water or other fluid can be injected into and / or extracted from the experimental object through the water channel. The design of the water channel ensures that the fluid can circulate during the experiment, simulating the flow of water or other fluids in the gaps between soil particles in a real environment. This fluid control can not only accurately adjust the injection amount and extraction speed of the fluid, but also monitor the flow state of the fluid in real time through a flow meter and a pressure sensor, ensuring the controllability of the experimental process and the accuracy of the data. The movement direction of at least one load application end is the same as the conduction direction. This design optimizes the coordination of load application and fluid flow, ensures the synchronization of the fluid flow direction during load application, and avoids experimental errors caused by direction conflicts. Specifically, when the movement direction of the load application end is consistent with the conduction direction, the applied force can be more effectively transmitted to the experimental object, and the flow direction of the fluid is consistent with the direction of applied load, which helps to simulate the comprehensive mechanical behavior of load and fluid action in a real environment. This consistency in direction not only improves the simulation accuracy of the experiment, but also reduces the interference and instability caused by inconsistent directions, ensuring the reliability and repeatability of the experimental data.

[0042] The monitoring unit consists of a transmitter and a receiver. Its main function is to achieve real-time monitoring and data acquisition of the experimental object's structural morphology by transmitting and receiving monitoring signals. The transmitter transmits the monitoring signal along one propagation direction, while the receiver is located at the other end of the signal propagation path and is responsible for receiving the signal passing through the experimental object. This monitoring system can dynamically capture and record the structural changes of the experimental object under different stress states during the experiment, providing basic data support for subsequent data analysis and visualization.

[0043] The propagation direction of the transmitter and the conduction direction of the loading cavity intersect in the middle of the loading cavity. This design ensures that the monitoring signal can effectively cover the core area of ​​the experimental object, so that the signal can fully reflect the changes in the internal structure when passing through the experimental object. Specifically, when the monitoring signal emitted by the transmitter is transmitted along the propagation direction, the signal intersects with the conduction direction in the middle of the loading cavity. When passing through the experimental object, the signal will be affected by the internal structure and stress state of the experimental object, and then form a changing signal image at the receiving end. This intersection design not only optimizes the propagation path of the signal, but also enhances the sensitivity and accuracy of the signal to the internal stress distribution of the experimental object.

[0044] When the monitoring signal passes through the experimental object, it will be affected by the solid, liquid, and gas three-phase media and their mechanical behaviors inside the experimental object, resulting in different degrees of attenuation, reflection, and refraction. After being processed, the signal received by the receiving end can reflect the structural morphological changes of the experimental object under the current stress state. For example, by analyzing the intensity changes, propagation time, and phase differences of the signal, the displacement of soil particles, stress concentration areas, shear band formation, and the distribution of force chains can be inferred. This monitoring method based on signal transmission characteristics can realize real-time, non-invasive monitoring of the microscopic mechanical behavior inside the experimental object, greatly improving the accuracy and visualization of experimental data.

[0045] The monitoring part is closely integrated with other device features such as the loading part, the load application end and the water channel, forming a highly integrated experimental platform. In the loading cavity in the center of the loading part, the load application end applies multi-directional and multi-parameter loads, and works together with the fluid flow in the water channel to simulate a complex fluid-solid coupling environment. In this process, the monitoring part captures the structural changes of the experimental object under the action of load and fluid in real time through the transmitting and receiving ends, ensuring all-round monitoring and data collection of the experimental process. In addition, the signal transmission and receiving functions of the monitoring part are combined with the central multi-load application and separate adjustment system, allowing researchers to adjust and monitor the structural response of the experimental object in real time while applying loads. This real-time feedback mechanism not only improves the controllability and flexibility of the experiment, but also provides rich empirical basis for subsequent data analysis and theoretical research. Through the coordinated work of the monitoring part and other device features, the entire experimental device can realize comprehensive and accurate simulation and analysis of the complex mechanical behavior of solid particles, liquid and gas in soil under the three-phase coupling.

[0046] Specifically, the parameter visualization mechanics experimental device also includes a lower bracket 1 and an upper bracket 3, the lower bracket 1 and the upper bracket 3 are assembled through a common fixed support plate 6, and the stress loading mechanism 2 is assembled on the upper surface of the support plate 6; the load applying end whose moving direction is the same as the conduction direction serves as an axial load applying mechanism 5, and the load applying end whose moving direction is different from the conduction direction serves as a lateral load applying mechanism 4.

[0047] As can be seen from the above, the upper surface of the fixed support plate 6 is the mounting base of the stress loading mechanism 2. This design ensures that the load application system can accurately apply the required stress to the experimental object. During the experiment, the working principle of the stress loading mechanism 2 is to achieve load action in different stress directions by accurately controlling the movement and position of the load application end on the basis of the platform. Since the movement direction of the load application end is directly related to the flow direction of the fluid, the design of the loading mechanism enables the experiment to simulate the stress distribution in different directions, so as to better explore the fluid-solid coupling mechanical behavior.

[0048] The movement direction of the load application end has significant functional differences. First, the load application end with the same movement direction as the conduction direction is used as the axial load application mechanism 5, which is used to apply the load along the fluid flow direction. During the experiment, the axial load application end can simulate the axial stress effect generated by the flow of fluid in the soil by controlling its movement direction and the amount of load applied, helping researchers to deeply analyze the mechanical properties of the soil under the interaction between the axial force and the fluid.

[0049] The load application end whose movement direction is different from the conduction direction serves as a lateral load application mechanism 4, and its main function is to apply a lateral load in a direction perpendicular to the fluid flow direction. In this way, the stress distribution and deformation mechanism of the soil under the action of a lateral load can be simulated. In the natural environment, the soil is often faced with lateral pressure, such as lateral water flow, seismic waves, wind force and other factors. The design of the lateral load application mechanism 4 can better reflect the actual impact of these natural factors on the soil, and thus provide key data for studying the mechanical behavior of the soil in a complex stress field. The load application ends in two different directions can be adjusted independently to achieve a variety of stress states, thereby helping the experiment to simulate various different environments and load conditions.

[0050] In any of the above embodiments, the parameter visualization mechanics experimental device further comprises:

[0051] At least one flexible block 12 is provided, and the flexible block 12 is connected to the load applying end; before the load applying end moves, the side wall of the flexible block 12 is in contact with the test object.

[0052] In this embodiment, the position of the flexible block 12 is set on at least one load application end and is connected to the load application end. Its main function is to ensure that the side wall of the flexible block 12 is tightly fitted with the surface of the experimental object before the load application end moves. This design ensures that before loading begins, the flexible block 12 can apply uniform initial pressure to the surface of the experimental object, so that a relatively stable contact state is formed between the experimental object and the load application end, preventing uneven loading or distortion of stress transfer due to poor contact. Therefore, the presence of the flexible block 12 makes the entire device more accurate when applying loads, ensuring the repeatability and reliability of the experiment.

[0053] When the load application end starts to move, the flexible block 12 plays a key role. Due to its certain flexibility and elasticity, the flexible block 12 can flexibly adjust its own deformation according to the movement direction of the load application end and the magnitude of the applied force to adapt to the deformation requirements of the experimental object. This feature is particularly suitable for simulating the flexible deformation behavior of soil, granular materials, etc. when subjected to loads, making the experimental process closer to the actual situation. In addition, the elastic characteristics of the flexible block 12 can also effectively avoid excessive concentrated loads, avoid local damage to the experimental object that may be caused by rigid components, and ensure a smooth transition and uniform distribution of the stress field in the experiment.

[0054] The connection method between the flexible block 12 and the load application end determines the stress transfer path and uniformity during the loading process. Through the setting of the flexible block 12, the load application end can apply stress more smoothly, while reducing the mechanical shock or uneven pressure fluctuations caused by the rigid connection. This design is particularly suitable for situations where experiments need to be conducted under more complex stress conditions, such as fluid-solid coupling, nonlinear stress distribution, etc., and can help researchers better understand the mechanical behavior of soil or other materials under different loads.

[0055] In any of the above embodiments, the flexible block 12 is connected to the load applying end via a buffer mechanism to maintain the position of the flexible block 12 in the loading chamber when the load applying end moves.

[0056] In this embodiment, the main function of the buffer mechanism is to absorb the kinetic energy generated by the load application or deformation of the test object when the load application end moves, reduce the vibration or irregular oscillation caused by the movement of the load application end or the flexible block 12, and thus maintain the stable position of the flexible block 12 in the loading chamber. In the fluid-solid coupling experiment, the interaction between the fluid and the solid material will lead to a complex dynamic response. The buffer mechanism can ensure that the test object maintains a stable stress state throughout the test process by suppressing unnecessary dynamic fluctuations.

[0057] When the load application end starts to move, the buffer mechanism absorbs the impact or shock during the movement through its elastic element or shock-absorbing component, making the movement smoother. In this way, the flexible block 12 can not only accurately follow the movement of the load application end, but also effectively avoid the displacement of the position of the flexible block 12 or the instability of the device due to excessive instantaneous pressure or too fast stress fluctuation. The flexible block 12 can work closely with the load application end during the experiment, while evenly transmitting the pressure, reducing irregular changes during the movement, thereby improving the accuracy of the experimental results.

[0058] The structural design of the buffer mechanism has a certain degree of flexibility and adjustability, and the amount of vibration absorbed and the shock absorption strength can be adjusted according to the needs of the experiment. When the load application end needs to move more significantly, the buffer mechanism can provide a stronger shock absorption effect to avoid excessive vibration during the experiment; when the load application end moves less or more slowly, the buffer mechanism can automatically adjust to a lighter buffer strength, thereby maintaining the stability of the device under different experimental conditions.

[0059] In addition, the close combination of the buffer mechanism and the flexible block 12 also makes the experimental process more flexible. The flexible block 12 no longer relies solely on a rigid connection, but through the adaptability of the buffer mechanism, it can flexibly adjust its deformation and position according to the movement of the load application end, while maintaining a uniform and stable pressure on the experimental object. This combination is particularly suitable for studying experimental materials with dynamic stress response and nonlinear behavior, such as soil or granular materials. When facing different load conditions, the buffer mechanism can ensure that the flexible block 12 adapts to the changing stress state, further enhancing the repeatability and reliability of the experiment.

[0060] In any of the above embodiments, the buffer mechanism includes:

[0061] The first rod body 11 is connected to the load application end along the moving direction, and the first rod body 11 is hollow; the side wall of the flexible block 12 is connected to the end surface of the first rod body 11 through a spring 13 .

[0062] The second rod 10 is arranged concentrically with the first rod 11, and the second rod 10 and the first rod 11 can move relative to each other along the movement direction; one end of the second rod 10 is connected to the flexible block 12, and the other end of the second rod 10 is detachably assembled on the experimental platform.

[0063] In this embodiment, the first rod body 11 is connected to the load application end along the direction of movement, and the first rod body 11 is hollow. This design not only reduces the weight of the structure, but also effectively reduces the inertia and kinetic energy generated during the experiment. When the load application end moves, the first rod body 11 is closely connected to it, and can transmit the movement of the load application end to the entire buffer mechanism, ensuring that the stress transmission during the movement is not disturbed. The hollow structure of the first rod body 11 helps to achieve more flexible stress adjustment and reduce the resistance generated by the device during movement.

[0064] One end of the first rod 11 is connected to the side wall of the flexible block 12 through a spring 13. The role of the spring 13 in this structure is to provide a restoring force, which can not only absorb the impact and vibration caused by the movement during the experiment, but also help restore the original position of the structure after the movement. By accurately adjusting the rigidity of the spring 13, the relative movement between the flexible block 12 and other structures can be effectively controlled to ensure that it always remains in a stable position during the entire experiment.

[0065] The second rod 10 is arranged concentrically with the first rod 11 and can move relative to each other along the direction of movement. The design of the second rod 10 makes the buffer mechanism more adaptable and can flexibly adjust the relative position between the two rods when the load application end moves. This design greatly improves the elasticity and responsiveness of the buffer mechanism, so that the second rod 10 can adjust its position and state according to the movement amplitude of the first rod 11, thereby effectively suppressing the propagation of impact force, vibration and irregular stress.

[0066] One end of the second rod body 10 is connected to the flexible block 12, and the other end is detachably mounted on the experimental platform. This assembly method enables the second rod body 10 to smoothly guide the movement of the flexible block 12 during movement, and at the same time, the disassembly and assembly design facilitates adjustment and maintenance. The role of the second rod body 10 in the buffer mechanism is to provide additional support force to ensure that the flexible block 12 can deform evenly when subjected to force without excessive displacement or irregular stress transfer. In addition, the detachable design of the second rod body 10 increases the flexibility of the experimental device, allowing experimenters to adjust the structure and function of the buffer mechanism according to different experimental requirements.

[0067] In any of the above embodiments, the circumferential side wall of the second rod body 10 outside the first rod body 11 is sleeved with the spring 13, and the connection between the spring 13 and the flexible block 12 and the inside of the water guide channel are respectively provided with pressure sensors.

[0068] The stress state includes the water pressure value of the test water and the pressure value acting on each flexible block 12.

[0069] In this embodiment, the position and structural design of the second rod body 10 ensure that it is arranged circumferentially outside the first rod body 11, forming a peripheral support for the buffer mechanism. Its main function is to guide and adjust the movement of the flexible block 12. At the same time, through the connection with the spring 13, when subjected to external forces, it can flexibly adjust the relative position with other components, reduce the impact, and control the vibration during the movement. Due to the unique position design of the second rod body 10, the elastic effect of the spring 13 mainly acts on the outer structure, so that the internal dynamic response is alleviated, thereby avoiding excessive impact force from being transmitted to the experimental object and other key structures, and ensuring the stability and accuracy of the experiment.

[0070] The pressure sensor arranged at the connection between the spring 13 and the flexible block 12 and the pressure sensor inside the water channel monitor the pressure changes at different positions respectively. The pressure sensor at the connection between the spring 13 and the flexible block 12 is mainly used to detect the pressure distribution of the flexible block 12 after being subjected to the load. These sensors can provide real-time feedback on the state of the flexible block 12 after being subjected to force, help to accurately control the deformation of the flexible block 12 in the experiment, and ensure that the flexible block 12 can evenly distribute the force to avoid experimental errors caused by uneven pressure. At the same time, the pressure sensor in the water channel is mainly used to monitor the water pressure value of the experimental water. By monitoring the water pressure in real time, the experimenter can accurately adjust the injection and extraction process of the fluid, thereby controlling the changes in the experimental environment, and studying the influence of water flow on soil particles, flexible blocks 12 and other objects.

[0071] The definition of stress state includes two key indicators: the water pressure value of the experimental water and the pressure value acting on each flexible block 12. The water pressure value of the experimental water refers to the external pressure exerted on the experimental object by the water injected or extracted through the water channel during the experiment. This water pressure directly affects the stress condition and mechanical response of the experimental object. The pressure sensor can feedback the change of water pressure in real time and transmit these data to the control system to help the experimenter understand the size and change of the external force exerted by the water flow on the experimental object. The pressure value acting on each flexible block 12 is obtained by monitoring the pressure state of each flexible block 12 after being stressed. These pressure values ​​directly reflect the combined effect of internal and external stresses borne by the flexible block 12 during the experiment. In the experiment, the deformation and stress state of the flexible block 12 are the key to studying the mechanical behavior of soil. Therefore, real-time monitoring of these pressure data by pressure sensors can provide accurate basis for analyzing and verifying key mechanical characteristics such as stress transfer, particle contact stress, and shear band formation during the experiment.

[0072] Furthermore, the lateral load applying mechanism 4 includes a first stepper motor 401, a second stepper motor 402, a central bearing 403, an upper clamping plate 404, a lower clamping plate 405, a frame plate 406, a push rod 407, a front push plate 408, a rear push plate 409, and a truncated cone-shaped clamping block 414. The end of the second rod body 10 is connected to the flexible block 12, and the tail is clamped between the upper clamping plate 404 and the lower clamping plate 405 through the truncated cone-shaped clamping block. The spring 13 is sleeved on the second rod body 10 between the flexible block 12 and the first rod body 11, and the spring 13 and the second rod body 10 between the push plate are covered with a first rod body 11 slightly larger than the second rod body 10. The upper clamping plate 404 is connected to the first stepper motor 401, and is arranged on the frame plate 406 together with the lower clamping plate 405. The frame plate 406 is fixed on the support plate 6. The front push plate 408 is pushed by the second stepper motor 402, driving the push rod 407 to move forward, thereby moving the rear push plate 409 forward, compressing the spring 13 through the first rod body 11, and fixing the push rod 407 on the bracket by bolts, thereby fixing the compression amount of the spring 13 and storing the propulsion force as the elastic force of the spring 13. Subsequently, under the control of the first stepper motor 401, the upper clamping plate 404 is moved upward, and at the same time, the central bearing 403 rotates, driving the lower clamping plate 405 to move downward, and then the second rod body 10 sandwiched between the upper and lower clamping plates 405 moves forward together, slowly releasing the load, thereby applying lateral confining pressure.

[0073] As can be seen from the above, in the lateral load application mechanism 4, the first stepper motor 401 and the second stepper motor 402 are responsible for controlling two key movement directions respectively. The first stepper motor 401 mainly controls the vertical lifting of the upper clamping plate 404, while the second stepper motor 402 controls the forward and backward movement of the front push plate 408. The cooperation of these two motors ensures precise movement during the load application process, and can adjust the direction and size of the load application according to the experimental needs. Through the control of the first stepper motor 401, the lifting and lowering amplitude of the upper clamping plate 404 can be ensured, and the rotation of the central bearing 403 can be coordinated to achieve the stable application of lateral confining pressure to the experimental object.

[0074] The design of the upper clamping plate 404 and the lower clamping plate 405 provides a solid support structure for load application. The upper clamping plate 404 can rise or fall in the vertical direction under the drive of the motor by connecting to the first stepper motor 401. The lower clamping plate 405 is connected to the upper clamping plate 404 through the central bearing 403 and is jointly arranged on the frame plate 406. Through this configuration, the upper clamping plate 404 and the lower clamping plate 405 can move synchronously during the experiment to ensure that the experimental object is always kept in the correct position. The frame plate 406, as a supporting component, is firmly fixed on the support plate 6, providing a stable foundation for the entire device and avoiding displacement and deviation during the movement.

[0075] The linkage design of the push rod 407 and the front push plate 408 and the rear push plate 409 is one of the core links of the device for applying lateral loads. The second stepper motor 402 drives the push rod 407 forward by driving the movement of the front push plate 408. The advancement of the push rod 407 causes the rear push plate 409 to move forward accordingly, and this process gradually increases the degree of compression of the spring 13. Specifically, the connection between the push rod 407 and the spring 13 is achieved through the first rod body 11. When the push rod 407 moves forward, it will compress the spring 13, so that the spring 13 stores a propulsion force. At this time, the push rod 407 is fixed to the bracket by bolts to ensure that the compression amount of the spring 13 does not change, thereby converting the propulsion force into the elastic force of the spring 13, preparing for the subsequent load release.

[0076] In the design of the lateral load applying mechanism 4, the spring 13 plays a key role. The spring 13 is arranged between the flexible block 12 and the first rod body 11, and its function is to compress and store energy when the push rod 407 is pushed forward. The compression amount of the spring 13 is fixed by bolts and brackets, ensuring the controllability of the compression amount, so that the propulsion force can be stably stored in the spring 13. When the first stepper motor 401 drives the upper clamping plate 404 to move upward, the system slowly releases the propulsion force stored in the spring 13, and gradually applies the lateral load to the experimental object.

[0077] The tail of the second rod 10 is fixed between the upper clamping plate 404 and the lower clamping plate 405 by a truncated cone-shaped clamping block 414, thereby ensuring that the second rod 10 can be firmly connected to the experimental device when a lateral load is applied. The design of the truncated cone-shaped clamping block 414 enables the second rod 10 to maintain a stable position and effectively transmit mechanical effects when subjected to compression and lateral forces. Through this arrangement, the cooperation of the second rod 10 and the flexible block 12 can accurately adjust the stress state of the experimental object and avoid any errors caused by the instability of the clamping block.

[0078] The load application process is precisely adjusted through the linkage control of the first stepper motor 401 and the second stepper motor 402, combined with the compression of the spring 13. At the beginning of the experiment, the front push plate 408 is pushed by the second stepper motor 402, driving the push rod 407 to move forward, thereby compressing the spring 13 and storing the propulsion force. When the first stepper motor 401 starts working, it drives the upper clamping plate 404 to gradually rise, driving the lower clamping plate 405 to move downward, and the second rod body 10 moves forward accordingly, slowly releasing the elastic force of the compressed spring 13, and applying the lateral load to the experimental object. This process is continuous and controllable. The experimenter can achieve precise control of the load application process by adjusting the movement speed of the motor and the compression amount of the spring 13 to ensure the accuracy of the experimental data.

[0079] Furthermore, the axial load applying mechanism 5 includes a third stepping motor 501 and a loading plate 502. The loading plate 502 is moved forward under the control of the third stepping motor 501, so as to apply an axial load to the particle material sample in the transparent water tank 7.

[0080] As can be seen from the above, the third stepper motor 501 is the power source of the axial load applying mechanism 5, and is responsible for controlling the precise movement of the loading plate 502. In the experiment, the third stepper motor 501 drives the loading plate 502 to move forward or backward in the axial direction (i.e., the direction perpendicular to the experimental platform) by connecting with the loading plate 502. When the third stepper motor 501 is started, it provides a steady and controllable thrust, so that the loading plate 502 can move forward slowly and steadily, thereby applying an axial load to the granular material sample located in the transparent water tank 7.

[0081] As the main component for applying load, the loading plate 502 directly contacts the experimental object and applies an axial load in the vertical direction to it. Under the control of the third stepper motor 501, the loading plate 502 can accurately move forward or backward along a single direction to ensure that the applied load has certain regularity and adjustability. During the experiment, when the loading plate 502 moves forward, the movement can evenly apply pressure on the experimental object, change its internal stress state, thereby simulating different mechanical action conditions. In addition, the forward movement of the loading plate 502 is not only a simple physical movement process, but also involves the distribution and transmission of the load in the entire experimental system. Through the movement of the loading plate 502, the applied load will evenly act on the surface of the experimental object, and then be transmitted to the entire sample through the mechanical properties of the object (such as deformation, compression, etc.). The accuracy and controllability of this process directly affect the accuracy and effectiveness of the experiment.

[0082] The connection and cooperation between the third stepper motor 501 and the loading plate 502 ensure that the applied axial load can maintain stable and accurate regulation in the experiment. By adjusting the movement speed of the third stepper motor 501, the experimenter can accurately control the forward speed of the loading plate 502, thereby controlling the rate and strength of load application. In addition, the third stepper motor 501 can also stop or reversely move the loading plate 502 at any time as needed during the experiment to simulate different load changes. This flexibility enables the device to cope with various experimental needs. In the experimental operation, the movement of the third stepper motor 501 is not limited to a single speed control, but can also be multi-dimensionally applied by cooperation with other load application systems (such as lateral load application mechanism 4). This multi-dimensional load application method helps to more comprehensively simulate the mechanical state in the actual working condition, especially in the study of material behavior under multiple stress states.

[0083] In any of the above embodiments, when the experimental object is in a stress state, the following conditions exist:

[0084] In case 1, the water channel is closed and the experimental water volume in the loading chamber is maintained to adjust the water pressure value.

[0085] In case 2, the water channel is opened and the amount of experimental water in the loading chamber is changed to adjust the pressure value.

[0086] In this embodiment, in case one, the water channel is closed while keeping the experimental water volume in the loading chamber where the experimental object is located unchanged. At this time, the closure of the water channel means that the experimental water cannot enter or discharge the loading chamber, thereby forming a closed water circulation system. In this case, the water pressure value in the loading chamber is no longer affected by the change of water flow, but is determined by the original amount of water and the compression of the experimental object. When the experimental object is in a stress state under this condition, the water pressure value will depend on the volume of water and the spatial structure of the loading chamber. Because the experimental water volume remains unchanged, any deformation of the experimental object (such as compression or expansion) caused by the application of external loads may cause a change in the water pressure value. Specifically, when the experimental object is subjected to external force, its volume change may cause a change in the pressure of the water body inside the water chamber. This water pressure change can be monitored in real time by relevant sensors and used to evaluate the hydraulic response characteristics of the experimental object after being subjected to force. At this time, the main purpose of the experiment is to control the water pressure in a closed water chamber to study the mechanical properties of the experimental object and its response to water pressure changes under different water pressure conditions.

[0087] In the second case, the water channel is opened, so that the experimental water can flow into or out of the loading chamber, thereby changing the amount of experimental water in the loading chamber. In this case, the fluidity of the water enables the experimenter to control the pressure value in the loading chamber by adjusting the amount of water, thereby affecting the mechanical environment of the experimental object. By changing the amount of water, the experimenter can adjust the pressure of the experimental water, thereby applying different water pressures to the experimental object. After opening the water channel, the inflow and outflow of water will not only affect the water pressure, but also may change the water environment of the experimental object. As water flows into the loading chamber, the volume of water increases, which will increase the pressure inside the loading chamber, especially in a closed chamber. The increase in water pressure will directly act on the experimental object, thereby affecting its stress state. When the water flows out of the loading chamber, the amount of water decreases, the pressure decreases accordingly, and the stress state of the experimental object will also change accordingly. Through this process, the opening of the water channel and the change of the experimental water volume provide the device with a flexible pressure regulation method, allowing the experimenter to accurately control the water pressure environment in which the experimental object is located. This process not only helps to study the response characteristics of the experimental object under different pressure conditions, but also can simulate the impact of changes in water flow on the behavior of objects in actual situations.

[0088] In any of the above embodiments, at least one buffer mechanism is provided on the same load applying end, and the elastic coefficients of all springs 13 corresponding to the same load applying end are the same or different.

[0089] In this embodiment, at least one spring 13 can be provided on each load application end to achieve a smooth transition during the load application process. As required, the elastic coefficients of these springs 13 can be the same or different. The elastic coefficient of the spring 13 refers to the ability of the spring 13 to return to its original state after being subjected to force, in other words, it determines the rigidity or elastic strength of the spring 13. When the load application end applies a load through a buffer mechanism, the elastic coefficient of the spring 13 will directly affect the speed and intensity of the load application. If the elastic coefficients of the springs 13 are the same, then under the action of all springs 13, the applied load will show a uniform buffering effect. The reaction force of each spring 13 is consistent, so the movement of the load application end will be uniform, and the force distribution is relatively balanced. This configuration is suitable for experimental scenarios that require uniform load application and maintain a relatively stable mechanical response. However, when the elastic coefficients of the springs 13 are different, the buffer mechanism exhibits more complex mechanical characteristics. At this time, different springs 13 react differently to the load application, so that the force of different parts can be adjusted. This setting is particularly suitable for experimental situations that require fine control of the load application ends at different positions. By selecting different elastic coefficients of the springs 13, the intensity and distribution of the load can be adjusted in a targeted manner during the experiment to meet specific experimental requirements. For example, some areas may require a stronger elastic coefficient to cope with higher loads, while other areas may require a lower elastic coefficient to slow down the speed or intensity of the applied load.

[0090] In any of the above embodiments, the experimental object includes a plurality of reflective particles, and a water-conducting gap is formed between the reflective particles; the flexible block 12 corresponds to the plurality of reflective particles along the moving direction.

[0091] In this embodiment, the main function of the reflective particles is to serve as a basic component of the experimental object. They not only play a role in mechanical response in the experiment, but also help to observe the behavior of the experimental object through the signal detection system of the monitoring unit. The surface of the reflective particles is covered with a special reflective material, which enables them to reflect clear signals under the illumination of a specific light source. The particles are connected by tiny water-conducting gaps. This design imitates the void structure in actual natural materials (such as sand, soil particles, etc.). In the experiment, these gaps not only allow fluids (such as water or experimental liquids) to flow between the particles, but also affect the mechanical response of the particles. The flow of fluid can produce fluid dynamics between the particles, change the mutual force between the particles, and then affect the mechanical properties and experimental results of the entire system.

[0092] The water-conducting gap allows liquid or other fluids to flow between particles, simulating the transmission process of fluids through pores in actual materials. This flow of fluid not only helps maintain the mechanical balance between particles, but also simulates various mechanical behaviors in experiments, such as shear, friction, and interactions between particles. Secondly, the water-conducting gap helps to accurately measure the dynamic response of granular materials in liquids. During stress loading, the flow of fluid is closely related to the mechanical response of particles, and factors such as gap size and flow rate will affect the stress distribution between particles. By measuring and controlling these factors, experimenters can deeply analyze the behavior of particles in a fluid environment.

[0093] The flexible block 12 is connected to the load application end through a buffer mechanism and corresponds to multiple reflective particles along the direction of movement. When pressure is applied at the load application end, the flexible block 12 interacts with the reflective particles, causing the particles to deform or move slightly. Since the flexible block 12 contacts multiple reflective particles along the direction of movement during the load application process, this contact will directly affect the movement and deformation of the reflective particles, and further affect the measurement and recording of the mechanical behavior in the experiment. The reflective particles will feed back the mechanical effects they are subjected to to the monitoring system in real time through the reflection signal on their surface.

[0094] In any of the above embodiments, the loading portion is made of a light-transmitting material, and the monitoring signal includes a light signal.

[0095] The structural form acquired by the optical signal is photoelastic stripes, and the image data containing the photoelastic stripes is used as the output of the parameter visualization mechanics experimental device.

[0096] In this embodiment, in the experiment, the light source emits a light signal through the loading part, and the light transmission property ensures that the light signal can pass through the experimental object or reflective particles smoothly without obstruction, and finally reaches the monitoring system. The choice of this material ensures the efficient transmission and accurate reflection of the light signal, which helps to obtain the structural response and changes of the experimental object. The light-transmitting material not only plays the role of allowing the light signal to pass through, but also optimizes the stability of the experimental environment through its transparency and optical properties. It can effectively reduce the influence of external light sources and ensure that the intensity and quality of the light signal emitted in the experiment are not disturbed, so that the experimental data is more accurate and reliable. Its high transparency also allows the system to clearly observe the formation and change process of photoelastic stripes, providing clear and visible experimental results for further mechanical analysis. In the monitoring signal, the acquisition of light signals is a key part. The light signal changes through the deformation, displacement, stress transfer and other behaviors of the experimental object, and the manifestation of this change is photoelastic stripes. Photoelastic stripes are a visual interference fringe pattern formed by the refraction, reflection or scattering effect when light passes through a stressed or deformed material. This stripe pattern is a direct reflection of the stress and deformation of the material, with very high accuracy and distinguishability. When the test object or reflective particles are deformed under the action of external stress, the light-transmitting material transmits the signal of the light source to the test object, and the light signal changes through the deformed area, eventually forming unique photoelastic stripes. These stripes reflect the internal stress distribution, deformation degree and strain state of the material, and are the basis for obtaining mechanical data in optical monitoring.

[0097] The photoelastic stripes obtained through the optical signal can accurately observe the structural changes of the experimental object under different stress states. Photoelastic stripes are not just visual interference patterns, they represent the distribution of stress inside the material, the mechanical response between particles, and the deformation of the material. The position, density, shape, and direction of each photoelastic stripe can accurately reflect the deformation of the experimental object, the stress concentration area, and the possible force chain transmission path. These stripe patterns are captured by the camera or other sensors in the monitoring system and processed and analyzed by specific software. By calculating and comparing the changes in photoelastic stripes, the experimenter can obtain visual data on the stress state at each stage, the force changes of the material, and the mechanical behavior inside the system. These data not only provide an intuitive basis for understanding the mechanical response of the experimental object under different loading conditions, but also provide a scientific basis for optimizing the design and application of materials.

[0098] Furthermore, the loading part includes two transparent water tank plates 7 that are interlocked with each other from top to bottom, and grooves are respectively provided on the longitudinally opposite surfaces of the transparent water tank plates 7, and the two grooves are combined to form a loading cavity; the transparent water tank plate 7 is placed in the center of the visual loading mechanism, and is mounted on the upper part of the support plate 6 through four pins located around it. The support plate and the loading part together constitute an experimental platform, and the plane of interest of the experimental platform is the horizontal xy plane.

[0099] As can be seen from the above, the structural design of the transparent water tank plate 7 is carefully designed according to the experimental requirements. Each transparent water tank plate 7 is provided with grooves on the longitudinal opposite surfaces, and these two grooves cooperate with each other during the assembly process of the loading part to form a loading cavity. As the core part of the loading part, the loading cavity has the main function of accommodating the experimental objects and providing sufficient space for applying loads. During the experiment, the loading cavity is not only a container, but also undertakes the multiple tasks of bearing, protecting and transferring loads. By accommodating the experimental objects, the loading cavity provides the necessary space for applying stress and monitoring the structural changes of the experimental objects. The grooves of the transparent water tank plate 7 not only provide physical space for the load, but also can optimize the deformation performance of the experimental objects under stress through reasonable groove shape and configuration. The shape and size design of each groove will affect the mechanical response of the water tank plate and the stability of the experimental objects.

[0100] The transparent water tank plate 7 is placed in the center of the visual loading mechanism. This design makes the transparent water tank plate 7 the core conductor of the optical signal during the experiment. Since the water tank plate is made of transparent material, the stress state of the experimental object can be presented in a visual way during the loading process. The loading chamber provides a clearly visible space for the experimenter through the transparent water tank plate 7, and the mechanical response of the experimental object under different loading conditions and its slight changes can be directly observed. In addition, the installation position of the transparent water tank plate 7 is also very critical. It is installed on the upper part of the support plate 6 through four pins located around it. These pins ensure the stability and precise positioning of the transparent water tank plate 7. The pins are connected through a tight structure, so that the transparent water tank plate 7 will not be displaced or loosened during the experiment, thereby ensuring the accuracy and stability of the experimental data. As a supporting device, the support plate 6 firmly fixes the transparent water tank plate 7 in the center of the visual loading mechanism, providing a stable platform for loading and monitoring.

[0101] The grooves of the transparent water tank plate 7 are combined into a loading cavity to accommodate the experimental object and provide a loading space for the experimental object. In this space, the experimental object can be deformed or responded under stress.

[0102] Furthermore, the water guide channel includes a liquid injection channel 701 and a corresponding liquid discharge channel 702 respectively located at two ends of the transparent water tank plate 7 .

[0103] As can be seen from the above, the injection channel 701 is located at one end of the transparent water tank plate 7, and its main function is to change the amount of liquid in the loading chamber by liquid injection, thereby adjusting the environmental pressure of the experimental object. By controlling the switch of the injection channel 701, the experimenter can accurately adjust the liquid flow rate entering the loading chamber and the initial pressure of the liquid. The setting of the injection channel 701 ensures that liquid can flow into the experimental chamber continuously from the outside and interact with the experimental object in the loading chamber. The size, shape and inlet position of the injection channel 701 are designed with consideration of the uniformity of liquid flow and the stability of pressure. The injection of liquid through the injection channel 701 not only provides a pressure source for the experimental object, but also can observe and record the dynamic response of the experimental object under different stress states by adjusting the amount of liquid.

[0104] The drainage channel 702 opposite to the injection channel 701 is arranged at the other end of the transparent water tank plate 7, and its main function is to allow liquid to be discharged from the loading chamber, thereby controlling the amount of liquid in the chamber and its pressure change. The setting of the drainage channel 702 ensures the bidirectional controllability of liquid flow during the experiment. Through the drainage channel 702, the experimenter can accurately control the discharge speed and pressure change of the liquid when applying the load or adjusting the experimental conditions, avoid excessive accumulation or deficiency of the liquid, and thus ensure the stability of the experimental environment. The drainage channel 702 not only plays the role of liquid discharge, but also helps to maintain the balance of the experimental environment. For example, under certain experimental conditions, it may be necessary to reduce the pressure in the loading chamber by drainage, or to discharge excess liquid to adapt to the deformation of the experimental object. The design of the drainage channel 702 cooperates with the injection channel 701 to achieve accurate control of the amount of liquid in the loading chamber, so that the deformation or reaction of the experimental object under different stress states can be accurately captured and analyzed. The synergy between the injection channel 701 and the drainage channel 702 is the key to the experimental device's ability to accurately control liquid pressure and experimental environment. By operating these two channels at the same time, the experimenter can accurately control the liquid environment in which the experimental object is located, so that when it is subjected to different stresses, the flow and pressure changes of the liquid can be adjusted within a precise range. For example, during the experiment, a certain amount of liquid is injected into the loading chamber through the injection channel 701, thereby increasing the liquid pressure of the loading chamber; and the excess liquid is discharged through the drainage channel 702, which can reduce the liquid pressure in the chamber, or be used to restore a certain liquid equilibrium state. The synergy of the two channels enables the change of the liquid environment to adapt to different experimental needs, while avoiding the influence of the experimental results due to uneven liquid flow or excessive pressure fluctuations. During the mechanical experiment, the injection and discharge of the liquid directly affect the stress state of the experimental object. The synergy of the injection and drainage channels 702 ensures the controllability of the liquid flow and ensures that the influence of the liquid environment on the experimental object remains within a preset range.

[0105] In any of the above embodiments, the loading portion is located between the transmitting end and the receiving end, and the propagation direction is arranged in the same direction as the normal direction of the plane.

[0106] Specifically, the transmitting end includes a light source, a polarizer and a quarter wave plate which are arranged on the lower bracket 1 in sequence from bottom to top, and the receiving end includes a quarter wave plate, an analyzer and a camera which are arranged on the upper bracket 3 in sequence from bottom to top. The light source is used to form a polarizer for plane polarized light, a quarter wave plate for forming a circular polarization field, an analyzer for filtering the polarized light in its direction, and a camera for collecting pictures, wherein the polarizer and the camera are respectively arranged on opposite sides of the visualization loading device, and a quarter wave plate is arranged between the polarizer and the visualization loading device and between the camera and the visualization loading device. The light emitted by the light source propagates in sequence along the polarizer, the quarter wave plate, the visualization loading device, the quarter wave plate, the analyzer and the camera, and ensures that the light emitted by the light source propagates to the particles in the visualization loading device.

[0107] As can be seen from the above, the transmitting end includes a light source, a polarizer and a quarter wave plate which are arranged from bottom to top on the lower bracket 1. The functions of these components are closely related to their arrangement order, and they are precisely optically coordinated with each other to ensure that the light can propagate on the correct path and form the required polarization state.

[0108] The light source is the starting point of the entire optical system and is responsible for emitting preliminary light. In this device, the role of the light source is not just to simply emit light, but also to provide a beam of sufficient intensity and stability to ensure that the subsequent optical elements can effectively modulate and process the beam. In particular, the light emitted by the light source is guided through the subsequent polarization element to form plane polarized light.

[0109] The polarizer is located between the light source and the quarter-wave plate. Its main function is to convert the natural light emitted from the light source into plane polarized light. By adjusting the angle of the polarizer, it is possible to ensure that the direction of the plane polarized light meets the experimental design requirements. The introduction of plane polarized light provides the basis for subsequent polarization modulation.

[0110] The quarter wave plate at the transmitting end is located after the polarizer. The function of the quarter wave plate is to convert plane polarized light into circularly polarized light. Circularly polarized light has a specific rotation direction, which can better transmit stress information when interacting with the experimental object. The design of the quarter wave plate is closely related to its material properties. Only through precise modulation can an ideal circular polarization field be formed, so that the response of the particles under different stress states in the experiment can be more accurately transmitted to the receiving end.

[0111] The receiving end includes a quarter wave plate, an analyzer and a camera which are arranged on the upper bracket 3 in order from bottom to top. The design of the receiving end is closely connected with the optical path of the transmitting end, and is mainly responsible for capturing the light signal that changes after passing through the experimental object (granular material sample) and converting it into data for analysis.

[0112] The quarter-wave plate at the receiving end is located before the analyzer. Its main function is to modulate the optical signal transmitted after passing through the experimental object and restore it to a polarization state suitable for detection. The optical signal passing through the experimental object is often affected by the stress field and physical changes. The quarter-wave plate converts these changes into changes that can be detected by the analyzer through its optical properties, thus providing conditions for subsequent signal interpretation.

[0113] The analyzer is located after the quarter wave plate and its function is to filter and select polarized light in a specific direction. The setting of the analyzer ensures that only the light signal that meets the requirements can be transmitted to the camera, avoiding signal interference and improving the signal-to-noise ratio.

[0114] The camera is located at the end of the receiving end and is responsible for converting the light signal obtained after passing through the analyzer into visual image data. The image data captured by the camera can be further converted into visual parameters such as photoelastic stripes. These data are directly used as the output of the experimental device, reflecting the mechanical response of the experimental object under different stress states.

[0115] Another embodiment of the first aspect of the present invention provides an experimental method implemented according to the parameter visualization mechanics experimental device in any of the above embodiments. In some embodiments of the present invention, the experimental method includes the following steps:

[0116] S101, the test preparation phase, includes:

[0117] Before the load is applied, a large number of small cylindrical photoelastic particles are placed into the transparent water tank 7 with thin tweezers, and then water or other fluids are injected through the injection channel 701 by an external microfluidic pump, and the external liquid collecting box is used to collect the water or other fluids discharged from the drainage channel 702. Then, the light source is turned on, so that the light emitted by the light source is transmitted in sequence along the polarizer, quarter wave plate, visual loading mechanism, quarter wave plate, analyzer, and camera, and it is ensured that the light emitted by the light source is transmitted to the millimeter-sized particles.

[0118] S102, lateral load application phase, which includes:

[0119] Under the control of the first stepper motor 401, the upper clamping plate 404 and the lower clamping plate 405 are kept in close contact, and the tail of the guide rod is clamped between the upper clamping plate 404 and the lower clamping plate 405 through the truncated cone-shaped clamping block 414. Then, the front push plate 408 is pushed by the second stepper motor 402, driving the push rod 407 to move forward, so that the rear push plate 409 moves forward, the spring 13 is compressed through the sleeve, and the push rod 407 is fixed to the bracket by bolts, so as to fix the compression amount of the spring 13 and store the propulsion force as the elastic force of the spring 13. Then, under the control of the first stepper motor 401, the upper clamping plate 404 is moved up, and at the same time, the lower clamping plate 405 is driven to move down under the rotation of the central bearing 403, and then the guide rod clamped between the upper and lower clamping plates 405 moves forward together, slowly releasing the load, so as to apply lateral confining pressure.

[0120] S103, uniaxial compression load application stage, including:

[0121] The loading plate 502 is moved forward under the control of the third stepping motor 501 , thereby applying an axial load to the granular material sample in the transparent water tank 7 .

[0122] According to the above operation, the camera collects images during the loading process, and through computer software processing, the change in the magnitude of contact stress in the granular material, the formation process of the shear band, and the distribution and direction of the force chain can be intuitively observed.

[0123] The present invention provides an experimental method that can study the mechanical behavior of granular materials in a real fluid-solid coupling environment by precisely controlling the application of loads and the collection of mechanical parameters at multiple stages, especially the microscopic phenomena such as stress distribution, force chain structure, and shear band formation under lateral and axial loads. By combining optical imaging with data processing, complex mechanical processes can be deeply analyzed and visualized, thus providing strong experimental support and theoretical basis for related scientific research fields.

[0124] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0125] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A parameter visualization mechanical experimental device for fluid-solid coupling, characterized in that: include: A stress loading mechanism, which has an experimental platform and a plurality of load applying ends; The load applying ends are arranged circumferentially on the experimental platform, and each of the load applying ends can move independently to form a variety of stress states in the center of the experimental platform; The movement direction of each load application end is a uniaxial direction, and all the movement directions are located in a plane of the experimental platform; A loading part is arranged in the center of the experimental platform; the loading part has a loading cavity for accommodating the experimental object, and the load applying end extends from the outside of the loading part to the loading cavity; A water channel is provided on the side of the loading portion along a conducting direction; the water channel is connected to the loading cavity, and the water channel injects and / or extracts the experimental water from the experimental object through the loading cavity; the movement direction of at least one of the load applying ends is the same as the conducting direction; The monitoring part has a transmitting end and a receiving end; the transmitting end transmits a monitoring signal along a propagation direction, and the conduction direction and the propagation direction intersect at the middle of the loading cavity; the monitoring signal enters the receiving end after passing through the experimental object, and obtains the corresponding structural morphology of the experimental object under the current stress state.

2. The parameter visualization mechanics experimental device according to claim 1, characterized in that: Also includes: A flexible block, at least one of which is provided and connected to the load applying end; Before the load applying end moves, the side wall of the flexible block is in contact with the test object.

3. The parameter visualization mechanics experimental device according to claim 2, characterized in that: The flexible block is connected to the load applying end through a buffer mechanism to maintain the position of the flexible block in the loading cavity when the load applying end moves.

4. The parameter visualization mechanics experimental device according to claim 3, characterized in that: The buffer mechanism comprises: A first rod body is connected to the load applying end along the moving direction, and the first rod body is hollow; the side wall of the flexible block is connected to the end surface of the first rod body through a spring; The second rod body is arranged concentrically with the first rod body, and the second rod body and the first rod body can move relative to each other along the movement direction; one end of the second rod body is connected to the flexible block, and the other end of the second rod body is detachably assembled on the experimental platform.

5. The parameter visualization mechanics experimental device according to claim 4, characterized in that: The circumferential side wall of the second rod body located outside the first rod body is sleeved with the spring, and the connection between the spring and the flexible block and the inside of the water guide channel are respectively provided with pressure sensors; The stress state includes the water pressure value of the test water and the pressure value acting on each of the flexible blocks.

6. The parameter visualization mechanics experimental device according to claim 5, characterized in that: When the test object is in the stress state, the following conditions exist: Case 1: closing the water channel and maintaining the experimental water volume in the loading chamber to adjust the water pressure value; In case 2, the water guide channel is opened, and the amount of experimental water in the loading chamber is changed to adjust the pressure value.

7. The parameter visualization mechanics experimental device according to claim 4, characterized in that: At least one buffer mechanism is provided on the same load applying end, and the elastic coefficients of all springs corresponding to the same load applying end are the same or different.

8. The parameter visualization mechanics experimental device according to claim 2, characterized in that: The experimental object includes a plurality of reflective particles, and water-conducting gaps are formed between the reflective particles; the flexible block corresponds to the plurality of reflective particles along the moving direction.

9. The parameter visualization mechanics experimental device according to claim 8, characterized in that: The loading part is made of a light-transmitting material, and the monitoring signal includes a light signal; The structural form acquired by the optical signal is photoelastic stripes, and image data of the photoelastic stripes is used as the output of the parameter visualization mechanics experimental device.

10. The parameter visualization mechanics experimental device according to claim 1, characterized in that: The loading portion is located between the transmitting end and the receiving end, and the propagation direction is arranged in the same direction as the normal direction of the plane.

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