A parametric visualization mechanical experimental device for fluid-structure interaction

Abstract

This invention belongs to the field of mechanical property testing technology for particulate matter, specifically disclosing a parameter visualization mechanical experimental device for fluid-structure interaction, comprising: a stress loading mechanism having an experimental platform and multiple load application ends; a loading section located in the center of the experimental platform; the loading section having a loading cavity for accommodating experimental objects inside, with the load application ends extending from the outside of the loading section to the loading cavity; a water guiding channel opened on the side of the loading section along a guiding direction; the water guiding channel connecting to the loading cavity; the movement direction of the load application ends being the same as the guiding direction; and a monitoring section having a transmitting end and a receiving end; the transmitting end emitting a monitoring signal along a propagation direction. It has the following advantages: multiple load application ends achieve diverse stresses, the water guiding channel regulates water pressure to achieve fluid-structure interaction, and the monitoring section utilizes photoelastic fringes to acquire structural changes in real time, improving experimental flexibility, simulating real working conditions, and data accuracy, thus meeting diverse mechanical research needs.

Description

Technical Field

[0001] This invention relates to the field of mechanical property testing technology for particulate matter, and more specifically, to a fluid-structure interaction parameter visualization mechanical experimental device. Background Technology

[0002] Soil is composed of three phases: solid particles, liquid, and gas. The flow of water or other fluids through the gaps between soil particles triggers extremely complex and multi-scale mechanical behaviors. At the macroscopic scale, these mechanical behaviors are heavily influenced by microscopic structural features. Therefore, research at the microscopic scale not only helps to deepen the understanding of the essential mechanisms of macroscopic mechanical properties but also provides a scientific basis for related engineering design and academic research. While existing photoelastic experimental techniques have some involvement in analyzing stress distribution and deformation patterns in solid materials, they are typically only applicable to single-phase materials and cannot provide an effective experimental environment for soil, a system where solid, liquid, and gas coexist. This hinders in-depth research into the coupling effect between particles and fluid flow. Furthermore, current experimental setups for applying lateral loads mostly employ a simple rigid plate pressurization method, resulting in a limited load application form that is difficult to flexibly simulate complex stress fields. Even when flexible pressurization methods are used, precise load control is difficult. These technical limitations make it difficult for current research to simultaneously examine the true mechanical characteristics of soil particles and fluids at both the microscopic and macroscopic levels, thus affecting the accurate understanding and analysis of the intrinsic mechanisms of soil mechanical behavior.

[0003] To address this issue, a parametric visualization mechanical experimental device for fluid-structure interaction is proposed. Summary of the Invention

[0004] The present invention aims to provide a parameter visualization mechanical experimental device for fluid-structure interaction, in order to solve or improve the problem that existing photoelastic experimental techniques cannot effectively study the complex mechanical behavior of fluid flow and particle interaction in soil.

[0005] In view of this, a first aspect of the present invention is to provide a mechanical experimental apparatus for visualizing the parameters of fluid-structure interaction.

[0006] A first aspect of the present invention provides a parametric visualization mechanical experimental apparatus for fluid-structure interaction, comprising: a stress loading mechanism having an experimental platform and multiple load application ends; the load application ends are arranged circumferentially on the experimental platform, and each load application end is capable of moving independently to form multiple stress states at 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 section is disposed at the center of the experimental platform; the interior of the loading section has a loading cavity for accommodating experimental objects, and the load application ends are loaded from the outside of the loading section. The part extends to the loading cavity; a water guiding channel is provided on the side of the loading part along a guiding direction; the water guiding channel communicates with the loading cavity, and the water guiding channel injects and / or extracts experimental water from the experimental object through the loading cavity; the movement direction of at least one of the load application ends is the same as the guiding direction; a monitoring part has a transmitting end and a receiving end; the transmitting end transmits a monitoring signal along a propagation direction, the guiding 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 structural morphology of the experimental object under the current stress state.

[0007] In any of the above technical solutions, the parameter visualization mechanical experimental device further includes: a flexible block, at least one of which is provided, and the flexible block is connected to the load application end; before the load application end moves, the sidewall of the flexible block is attached to the experimental object.

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

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

[0010] In any of the above technical solutions, the second rod is sleeved on the circumferential sidewall outside the first rod, 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 under the stress state, the following situations exist: Situation 1: the water channel is closed, and the amount of experimental water in the loading cavity is maintained to adjust the water pressure value; Situation 2: the water channel is opened, and the amount of experimental water in the loading cavity is changed to adjust the pressure value.

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

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

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

[0015] In any of the above technical solutions, the loading part 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] The beneficial effects of this invention compared to the prior art are as follows:

[0017] By arranging multiple load application ends circumferentially on the experimental platform, and each load application end being able to move independently, multiple complex stress states can be formed simultaneously in the central region. This not only improves the flexibility and diversity of stress application, but also simulates more realistic and complex mechanical environments to meet different experimental needs.

[0018] The loading section is equipped with a water guiding channel, which can adjust the water pressure in the loading cavity by injecting and extracting experimental water, realizing the dynamic coupling of fluid and solid material. It can simulate the influence of fluid on soil or other particulate materials in actual engineering, such as the mechanical behavior under complex working conditions such as earthquakes, wind loads or water flow impacts, and provide a real and reliable experimental environment for fluid-structure interaction mechanics research.

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

[0020] Additional aspects and advantages of embodiments of the invention will become apparent in the following description or may be learned by practice of embodiments of the invention. Attached Figure Description

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

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

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

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

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

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

[0027] in, Figures 1-5 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0028] 1 Lower support, 2 Stress loading mechanism, 3 Upper support, 4 Lateral load application mechanism, 401 First stepper motor, 402 Second stepper 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, 411 First rod, 412 Flexible block, 413 Spring, 414 Frustum-shaped locking block, 5 Axial load application mechanism, 501 Third stepper motor, 502 Loading plate, 6 Support plate, 7 Transparent water tank plate, 701 Injection channel, 702 Drainage channel. Detailed Implementation

[0029] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0031] Please see Figures 1-5The following describes a parametric visualization mechanical experimental apparatus for fluid-structure interaction according to some embodiments of the present invention.

[0032] An embodiment of the first aspect of the present invention provides a parametric visualization mechanical experimental apparatus for fluid-structure interaction. In some embodiments of the present invention, such as... Figures 1-5 As shown, the experimental setup for visualizing this parameter includes:

[0033] The stress loading mechanism 2 has an experimental platform and multiple load application ends. The load application ends are arranged circumferentially on the experimental platform, and each load application end can move independently and apply load independently. Multiple loads are applied in the center of the experimental platform and adjusted individually to form multiple stress states. The movement direction of each load application end is a single axis direction, and all movement directions are located in a plane of the experimental platform.

[0034] A loading section is located in the center of the experimental platform; the loading section has a loading cavity for accommodating the experimental object, and a load application end extends from the outside of the loading section to the loading cavity to apply a load to the experimental object; a water guiding channel is provided on the side of the loading section along a guiding direction; the water guiding channel connects to the loading cavity, and the water guiding channel injects and / or extracts experimental water from the experimental object through the loading cavity; the movement direction of at least one load application end is the same as the guiding direction.

[0035] The monitoring unit has a transmitter and a receiver. The transmitter emits a monitoring signal along a propagation direction, and the conduction direction and the propagation direction intersect in the middle of the loading cavity. The monitoring signal enters the receiver after passing through the experimental object and obtains the structural morphology of the experimental object under the current stress state.

[0036] This invention provides a parametric visualization experimental apparatus for fluid-structure interaction (FSI). The stress loading mechanism 2 comprises an experimental platform and multiple load application ends. The experimental platform is manufactured using high-strength, low-vibration materials to ensure that the platform itself does not undergo significant deformation or displacement when multi-directional loads are applied, thereby guaranteeing the accuracy and repeatability of experimental data. The experimental platform is designed as a transparent or semi-transparent structure, facilitating real-time observation of the interaction between fluid and solid particles, meeting the specific needs of FSI research. The multiple load application ends in the stress loading mechanism 2 are uniformly arranged along the circumference of the experimental platform. Each load application end is equipped with an independent drive device and control system, enabling it to move and apply loads independently. This arrangement ensures that the load is evenly distributed in all directions, providing a flexible experimental environment for simulating different stress states.

[0037] Multiple load application ends are evenly distributed circumferentially along the experimental platform to ensure a balanced distribution of loads in all directions. Each load application end is equipped with an independent drive device and control system, enabling it to 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 experimental needs, thereby simulating different stress states. For example, in soil fluid-structure interaction experiments, pressures in different directions can be applied through different load application ends to simulate various working conditions that may be encountered in actual engineering, such as earthquakes, wind loads, or water flow impacts. The independence of multiple load application ends combined with their circumferential distribution allows the experimental setup to apply loads of different directions and magnitudes during the same experiment, creating 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 fluid-structure interaction mechanisms.

[0038] Each load-applying end moves in a single-axis direction, and all load-applying ends move 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 single-axis motion direction makes the application process of each load-applying end more precise and predictable, avoiding the complexity and potential instability caused by multi-directional load superposition. The single-axis motion direction design allows the load-applying ends to work collaboratively within the same plane, forming 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 coupled in soil. Furthermore, the arrangement of motion directions within the same plane ensures the symmetry and coordination of load application, enabling each load-applying end to work collaboratively during the experiment, further improving the accuracy and reliability of the experimental data.

[0039] The loading section, located at the center of the experimental platform, is the core component of the entire experimental setup. Its internal design includes a loading cavity specifically for holding and securing the material samples to be tested, such as soil particles or other multiphase media. The loading cavity's design ensures the stability of the experimental material under stress and fluid forces, preventing displacement or deformation during the experiment, thereby improving the accuracy and repeatability of experimental data. The loading cavity is typically constructed of transparent materials, facilitating real-time monitoring of the internal state changes of the experimental material through a visualization system.

[0040] The load application end extends from the outside of the loading section into the loading cavity, and its main function is to apply loads to the experimental object. Each load application end is equipped with an independent drive device and control system, enabling it to move independently and apply loads. This design allows each load application end to independently adjust the magnitude, direction, and application time of the applied force according to experimental needs, thereby simulating different stress states. For example, in soil fluid-structure interaction experiments, 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 enables a more comprehensive simulation and analysis of the mechanical behavior of materials under complex stress conditions.

[0041] A water channel is provided on the side of the loading section along a guiding direction. This channel connects to the loading cavity, allowing experimental water or other fluids to be injected into and / or extracted from the experimental object. The design of the water channel ensures that the fluid circulates during the experiment, simulating the flow of water or other fluids in the gaps between soil particles in a real environment. This fluid control not only precisely adjusts the injection and extraction speeds but also monitors the fluid flow status in real time using flow meters and pressure sensors, ensuring the controllability of the experimental process and the accuracy of the data. At least one load application end moves in the same direction as the guiding direction. This design optimizes the coordination between load application and fluid flow, ensuring the synchronization of fluid flow direction during load application and avoiding experimental errors caused by directional conflicts. Specifically, when the load application end moves in the same direction as the guiding direction, the applied force can be more effectively transmitted to the experimental object. Simultaneously, the fluid flow direction aligns with the applied load direction, helping to simulate the combined mechanical behavior of load and fluid interaction in a real environment. This directional consistency not only improves the simulation accuracy but also reduces interference and instability caused by directional inconsistencies, ensuring the reliability and repeatability of 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 monitoring signals along one propagation direction, while the receiver is located at the other end of the signal propagation path, responsible for receiving signals 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 transmitting end and the conduction direction of the loading cavity intersect at the middle of the loading cavity. This design ensures that the monitoring signal can effectively cover the core area of ​​the experimental object, allowing the signal to fully reflect changes in the internal structure as it passes through the object. Specifically, when the monitoring signal emitted by the transmitting end propagates along the propagation direction, it intersects with the conduction direction at the middle of the loading cavity. As it passes through the experimental object, the signal is affected by the internal structure and stress state of the object, thus forming a changing signal image at the receiving end. This intersection design not only optimizes the signal propagation path but also enhances the signal's sensitivity and accuracy to the internal stress distribution of the experimental object.

[0044] When monitoring signals pass through experimental objects, they are affected by the solid, liquid, and gaseous three-phase media and their mechanical behavior within the objects, resulting in varying degrees of attenuation, reflection, and refraction. After processing, the received signals can reflect changes in the structural morphology of the experimental object under its current stress state. For example, by analyzing signal intensity changes, propagation time, and phase differences, the displacement of soil particles, stress concentration areas, the formation of shear bands, and the distribution of force chains can be inferred. This monitoring method based on signal transmission characteristics enables real-time, non-invasive monitoring of the microscopic mechanical behavior within experimental objects, significantly improving the accuracy and visualization of experimental data.

[0045] The monitoring unit, along with the loading unit, load application end, and water conduit, forms a highly integrated experimental platform. In the loading chamber at the center of the loading unit, the load application end applies multi-directional, multi-parameter loads, which interact with the fluid flow in the water conduit to simulate a complex fluid-structure interaction environment. During this process, the monitoring unit captures the structural changes of the experimental object under load and fluid action in real time through its transmitter and receiver, ensuring comprehensive monitoring and data acquisition throughout the experiment. Furthermore, the signal transmission and reception functions of the monitoring unit, combined with the central multi-load application and individual adjustment system, allow 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 evidence for subsequent data analysis and theoretical research. Through the collaborative work of the monitoring unit and other components, the entire experimental setup can achieve comprehensive and accurate simulation and analysis of the complex mechanical behavior under the coupling of solid particles, liquid, and gas in soil.

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

[0047] As described above, the upper surface of the fixed support plate 6 serves as the mounting base for 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 stress loading mechanism 2 operates on this platform by precisely controlling the movement and position of the load application end to achieve load application in different stress directions. Since the movement direction of the load application end is directly related to the fluid flow direction, the design of the loading mechanism allows the experiment to simulate stress distribution in different directions, thereby better exploring the fluid-structure interaction mechanics.

[0048] The movement directions of the load application ends are functionally distinct. First, the load application end with the same movement direction as the conduction direction is used as the axial load application mechanism 5, which applies load along the fluid flow direction. During the experiment, by controlling its movement direction and the amount of load applied, the axial load application end can simulate the axial stress effect generated by fluid flow in the soil, helping researchers to analyze the mechanical properties of the soil under the interaction of axial force and fluid.

[0049] The load application end, with a direction of motion different from the conduction direction, serves as the lateral load application mechanism 4. Its main function is to apply lateral loads in a direction perpendicular to the fluid flow direction. This allows for the simulation of stress distribution and deformation mechanisms in soil under lateral loads. In natural environments, soil frequently faces lateral pressures, such as those from lateral water flow, seismic waves, and wind. The design of the lateral load application mechanism 4 better reflects the actual impact of these natural factors on the soil, thus providing crucial data for studying the mechanical behavior of soil in complex stress fields. The two load application ends, operating in different directions, can be independently adjusted to achieve diverse stress states, thereby facilitating experimental simulations of various environmental and load conditions.

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

[0051] At least one flexible block 12 is provided, and the flexible block 12 is connected to the load application end; before the load application end moves, the sidewall of the flexible block 12 is attached to the experimental object.

[0052] In this embodiment, the flexible block 12 is positioned on at least one load-applying end and connected to it. Its main function is to ensure that the sidewalls of the flexible block 12 are in close contact with the surface of the experimental object before the load-applying end moves. This design ensures that the flexible block 12 can apply a uniform initial pressure to the surface of the experimental object before loading begins, resulting in a relatively stable contact state between the experimental object and the load-applying end, preventing uneven loading or distortion of stress transmission due to poor contact. Therefore, the presence of the flexible block 12 makes the entire device more precise when applying loads, ensuring the repeatability and reliability of the experiment.

[0053] When the load-applying end begins to move, the flexible block 12 plays a crucial role. Due to its flexibility and elasticity, the flexible block 12 can flexibly adjust its deformation according to the direction of movement and the magnitude of the applied force to adapt to the deformation requirements of the experimental object. This characteristic is particularly suitable for simulating the flexible deformation behavior of soil, granular materials, etc., under load, making the experimental process closer to reality. In addition, the elastic properties of the flexible block 12 can effectively avoid excessive load concentration, prevent local damage to the experimental object that rigid components may cause, and ensure a smooth transition and uniform distribution of the stress field during 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. By using the flexible block 12, stress can be applied more smoothly at the load application end, while reducing mechanical impact or uneven pressure fluctuations caused by rigid connections. This design is particularly suitable for experiments requiring complex stress conditions, such as fluid-structure interaction and nonlinear stress distribution, helping 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 application end through a buffer mechanism to maintain the position of the flexible block 12 in the loading cavity when the load application end moves.

[0056] In this embodiment, the main function of the buffer mechanism is to absorb the kinetic energy generated during load application or deformation of the experimental object when the load application end moves, thereby reducing vibrations or irregular oscillations caused by the movement of the load application end or the flexible block 12, and thus maintaining the stable position of the flexible block 12 within the loading cavity. In fluid-structure interaction experiments, the interaction between fluid and solid materials leads to complex dynamic responses. By suppressing unnecessary dynamic fluctuations, the buffer mechanism ensures that the experimental object maintains a stable stress state throughout the test.

[0057] When the load-applying end begins to move, the buffer mechanism absorbs the impact or vibration during the movement through its elastic elements or shock-absorbing components, making the movement smoother. In this way, the flexible block 12 can not only accurately follow the movement of the load-applying end, but also effectively avoid positional deviations or instability of the device caused by excessive instantaneous pressure or rapid stress fluctuations. The flexible block 12 can work closely with the load-applying end during the experiment, reducing irregular changes during movement while uniformly transmitting pressure, thereby improving the accuracy of the experimental results.

[0058] The buffer mechanism is designed with flexibility and adjustability, allowing for adjustments to the amount of vibration absorbed and the damping force according to experimental requirements. When the load application end needs to undergo a large-amplitude movement, the buffer mechanism provides strong damping to prevent excessive vibration during the experiment; while when the movement of the load application end is small or slow, the buffer mechanism automatically adjusts to a lighter damping force, thus maintaining the stability of the device under different experimental conditions.

[0059] Furthermore, the close integration of the buffer mechanism with the flexible block 12 makes the experimental process more flexible. The flexible block 12 no longer relies solely on a rigid connection; instead, through the adaptability of the buffer mechanism, it can flexibly adjust its deformation and position according to the movement of the load-applying end, while maintaining a uniform and stable pressure on the experimental object. This combination is particularly suitable for studying experimental materials with dynamic stress responses and nonlinear behaviors, such as soil or granular materials. Under different load conditions, the buffer mechanism ensures that the flexible block 12 adapts to changing stress states, further enhancing the repeatability and reliability of the experiment.

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

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

[0062] The second rod 10 is concentrically arranged with the first rod 11, and the second rod 10 and the first rod 11 can move relative to each other in the direction of movement; 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 11 is connected to the load application end along the direction of movement, and the first rod 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 11 is tightly connected to it, which 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 11 facilitates more flexible stress adjustment while reducing 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 via a spring 13. The function of the spring 13 in this structure is to provide restoring force, which not only absorbs the impact and vibration caused by the motion during the experiment, but also helps to restore the structure to its original position after the motion ends. By precisely adjusting the stiffness of the spring 13, the relative movement between the flexible block 12 and other structures can be effectively controlled, ensuring that it remains in a stable position throughout the entire experiment.

[0065] The second rod 10 is concentrically arranged with the first rod 11 and can move relative to each other along the direction of motion. The design of the second rod 10 makes the buffer mechanism more adaptable, allowing it to flexibly adjust the relative position between the two rods when the load-bearing end moves. This design greatly improves the elasticity and responsiveness of the buffer mechanism, enabling the second rod 10 to 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 10 is connected to the flexible block 12, while the other end is detachably mounted on the experimental platform. This assembly method allows the second rod 10 to smoothly guide the movement of the flexible block 12 during operation, and the detachable assembly design facilitates adjustment and maintenance. The function of the second rod 10 in the buffer mechanism is to provide additional support force, ensuring that the flexible block 12 deforms uniformly under stress, without excessive displacement or irregular stress transmission. Furthermore, the detachable design of the second rod 10 increases the flexibility of the experimental setup, allowing experimenters to adjust the structure and function of the buffer mechanism according to different experimental needs.

[0067] In any of the above embodiments, the second rod 10 is sleeved with a spring 13 on its circumferential sidewall outside the first rod 11, and pressure sensors are respectively provided at the connection between the spring 13 and the flexible block 12 and inside the water guiding channel.

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

[0069] In this embodiment, the position and structural design of the second rod 10 ensures that it is circumferentially positioned outside the first rod 11, forming an outer support for the buffer mechanism. Its main function is to guide and adjust the movement of the flexible block 12. Simultaneously, through its connection with the spring 13, it can flexibly adjust its relative position to other components when subjected to external forces, mitigating impact and controlling vibration during movement. Due to the unique positional design of the second rod 10, the elastic effect of the spring 13 primarily acts on the outer structure, thus mitigating the internal dynamic response and preventing excessive impact force from being transmitted to the experimental object and other critical structures, ensuring the stability and accuracy of the experiment.

[0070] Pressure sensors located at the connection between spring 13 and flexible block 12, and inside the water channel, monitor pressure changes at different locations. The pressure sensor at the connection between spring 13 and flexible block 12 primarily detects the pressure distribution of flexible block 12 under load. These sensors provide real-time feedback on the state of flexible block 12 under stress, helping to precisely control its deformation during experiments and ensuring uniform stress distribution, thus avoiding experimental errors caused by uneven pressure. Simultaneously, the pressure sensor inside the water channel monitors the water pressure of the experimental water. By monitoring the water pressure in real time, researchers can precisely adjust the fluid injection and extraction processes, thereby controlling changes in the experimental environment and studying the effects of water flow on soil particles, flexible block 12, and other objects.

[0071] The definition of stress state includes two key indicators: the water pressure of the experimental water and the pressure acting on each flexible block 12. The water pressure refers to the external pressure exerted on the experimental material by water injected or extracted through the water channel during the experiment. This water pressure directly affects the stress state and mechanical response of the experimental material. Pressure sensors can provide real-time feedback on water pressure changes and transmit this data to the control system, helping researchers understand the magnitude and changes of the external force exerted on the experimental material by the water flow. The pressure acting on each flexible block 12 is obtained by monitoring the pressure state of each flexible block 12 after being subjected to force. These pressure values ​​directly reflect the combined effect of internal and external stresses on the flexible block 12 during the experiment. In the experiment, the deformation and stress state of the flexible block 12 are crucial for studying soil mechanical behavior. Therefore, real-time monitoring of this pressure data by pressure sensors can provide accurate evidence for analyzing and verifying key mechanical characteristics such as stress transmission, particle contact stress, and shear band formation during the experiment.

[0072] Furthermore, the lateral load application 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 frustum-shaped locking block 414. The end of the second rod 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 by the frustum-shaped locking block. A spring 13 is sleeved on the second rod 10 between the flexible block 12 and the first rod 11, and a first rod 11 slightly larger than the second rod 10 is sleeved on the second rod 10 between the spring 13 and the push plate. The upper clamping plate 404 is connected to the first stepper motor 401 and is mounted on the frame plate 406 together with the lower clamping plate 405. The frame plate 406 is fixed to the support plate 6. The second stepper motor 402 pushes the front push plate 408, causing the push rod 407 to move forward, which in turn moves the rear push plate 409 forward. The first rod 11 compresses the spring 13, and the push rod 407 is fixed to the bracket with bolts, thus fixing the compression of the spring 13 and storing the propulsive force as the spring force of the spring 13. Subsequently, under the control of the first stepper motor 401, the upper clamping plate 404 moves upward, while the central bearing 403 rotates, causing the lower clamping plate 405 to move downward. This causes the second rod 10, which is clamped between the upper and lower clamping plates 405, to move forward together, slowly releasing the load and thus applying lateral confining pressure.

[0073] As described 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 motion directions, respectively. The first stepper motor 401 mainly controls the vertical lifting and lowering of the upper clamping plate 404, while the second stepper motor 402 controls the forward and backward movement of the push plate 408. The cooperation of these two motors ensures precise movement during the load application process and allows for adjustment of the direction and magnitude of the load application according to experimental needs. Through the control of the first stepper motor 401, the lifting and lowering range of the upper clamping plate 404 can be ensured, and in conjunction with the rotation of the central bearing 403, a stable application of lateral confining pressure to the experimental object can be achieved.

[0074] The upper clamping plate 404 and lower clamping plate 405 are designed to provide a robust support structure for load application. The upper clamping plate 404, connected to a first stepper motor 401, can rise or fall vertically under the motor's drive. The lower clamping plate 405 is connected to the upper clamping plate 404 via a central bearing 403 and both are mounted on the support plate 406. This configuration allows the upper and lower clamping plates 404 and 405 to move synchronously during the experiment, ensuring the experimental object remains in the correct position. The support plate 406, as a support component, is securely fixed to the support plate 6, providing a stable foundation for the entire device and preventing displacement and deviation during movement.

[0075] The linkage design of the push rod 407, the front push plate 408, and the rear push plate 409 is one of the core components of the device for applying lateral loads. The second stepper motor 402 drives the front push plate 408 to move, which in turn propels the push rod 407 forward. The forward movement of the push rod 407 causes the rear push plate 409 to move forward as well, gradually increasing the 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 compresses the spring 13, causing the spring 13 to store propulsive force. At this time, the push rod 407 is fixed to the bracket by bolts, ensuring that the compression of the spring 13 does not change, thereby converting the propulsive force into the elastic force of the spring 13, preparing for the subsequent load release.

[0076] In the design of the lateral load application mechanism 4, the spring 13 plays a crucial role. The spring 13 is positioned between the flexible block 12 and the first rod 11, and its function is to compress and store energy when the push rod 407 propels it forward. The compression of the spring 13 is fixed by bolts and a bracket, ensuring the controllability of the compression and thus allowing the propulsive force to be stably stored in the spring 13. When the first stepper motor 401 drives the upper clamping plate 404 upward, the system slowly releases the propulsive force stored in the spring 13, gradually applying 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 frustum-shaped locking block 414, thereby ensuring that the second rod 10 can be stably connected in the experimental apparatus when lateral loads are applied. The design of the frustum-shaped locking block 414 enables the second rod 10 to maintain a stable position under compression and lateral forces and effectively transmit mechanical forces. Through this arrangement, the cooperation between the second rod 10 and the flexible block 12 can precisely adjust the stress state of the experimental object and avoid any errors caused by the instability of the locking block.

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

[0079] Furthermore, the axial load application mechanism 5 includes a third stepper motor 501 and a loading plate 502. Under the control of the third stepper motor 501, the loading plate 502 is moved forward, thereby applying an axial load to the particulate material sample in the transparent water tank 7.

[0080] As described above, the third stepper motor 501 is the power source for the axial load application mechanism 5, responsible for controlling the precise movement of the loading plate 502. In the experiment, the third stepper motor 501, connected to the loading plate 502, drives it to move forward or backward along the axial direction (i.e., perpendicular to the experimental platform). When the third stepper motor 501 starts, it provides a smooth and controllable thrust, enabling the loading plate 502 to move forward slowly and steadily, thereby applying an axial load to the particulate material sample located in the transparent water tank 7.

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

[0082] The connection and coordination between the third stepper motor 501 and the loading plate 502 ensures that the applied axial load can be kept stable and precisely adjustable during the experiment. By adjusting the movement speed of the third stepper motor 501, the experimenter can precisely control the forward speed of the loading plate 502, thereby controlling the rate and force of load application. Furthermore, the third stepper motor 501 can stop or reverse the movement of the loading plate 502 at any time during the experiment as needed to simulate different load variations. This flexibility allows the device to meet various experimental requirements. In experimental operation, the movement of the third stepper motor 501 is not limited to single speed control; it can also apply loads in multiple dimensions by cooperating with other load application systems (such as the lateral load application mechanism 4). This multi-dimensional load application method helps to more comprehensively simulate the mechanical state in actual working conditions, especially in the study of material behavior under various stress states.

[0083] In any of the above embodiments, when the experimental object is under stress, the following situation exists:

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

[0085] In scenario two, 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 scenario one, the water channel is closed while maintaining a constant volume of experimental water within the loading chamber containing the experimental object. Closure of the water channel means that experimental water cannot enter or exit the loading chamber, thus forming a closed water circulation system. Under these conditions, the water pressure within the loading chamber is no longer affected by changes in water flow, but is determined by the existing water volume and the compression of the experimental object. When the experimental object is under stress under these conditions, the water pressure will depend on the volume of water and the spatial structure of the loading chamber. Because the volume of experimental water remains constant, any deformation of the experimental object caused by external loads (e.g., compression or expansion) may lead to changes in water pressure. Specifically, when the experimental object is subjected to external forces, its volume change may cause pressure changes in the water within the chamber. These pressure changes can be monitored in real time by relevant sensors and used to evaluate the hydraulic response characteristics of the experimental object under stress. The main objective of the experiment is to study the mechanical properties of the experimental object and its response to water pressure changes under different water pressure conditions within a closed water chamber by controlling the water pressure.

[0087] In scenario two, the water channel is opened, allowing experimental water to flow in and out of the loading chamber, thus altering the water volume within. In this case, the fluidity of the water allows researchers to control the pressure within the loading chamber by adjusting the water volume, thereby affecting the mechanical environment of the experimental object. By changing the water volume, researchers can adjust the water pressure, applying different water pressures to the experimental object. Opening the water channel not only affects the water pressure but may also alter the aquatic environment of the experimental object. As water flows into the loading chamber, its volume increases, increasing the pressure inside, especially in a closed chamber. This increased pressure directly affects the experimental object, influencing its stress state. When water flows out of the loading chamber, the volume decreases, the pressure drops, and the stress state of the experimental object changes accordingly. Through this process, the opening of the water channel and the change in the experimental water volume provide a flexible means of pressure regulation, allowing researchers to precisely control the aquatic pressure environment of the experimental object. This process not only helps in studying the response characteristics of experimental objects under different pressure conditions but also simulates the impact of changes in water flow on the behavior of objects in real-world situations.

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

[0089] In this embodiment, at least one spring 13 can be provided on each load application end to achieve a smooth transition during load application. The spring constants of these springs 13 can be the same or different, depending on the need. The spring constant of a spring 13 refers to its ability to return to its original shape after being subjected to force; in other words, it determines the stiffness or elastic strength of the spring 13. When the load application end applies a load through the buffer mechanism, the spring constant of the springs 13 directly affects the speed and intensity of the load application. If the spring constants of the springs 13 are the same, the applied load will exhibit a uniform buffering effect under the action of all springs 13. The reaction force of each spring 13 is consistent, therefore the movement of the load application end will be uniform, and the force distribution will be relatively balanced. This configuration is suitable for experimental scenarios that require uniform load application and a relatively stable mechanical response. However, when the spring constants of the springs 13 are different, the buffer mechanism exhibits more complex mechanical characteristics. In this case, different springs 13 react differently to the applied load, thus allowing for adjustment of the force in different parts. This setup is particularly suitable for experimental situations that require precise control of the load application ends at different locations. By selecting different spring constants for spring 13, the intensity and distribution of the load can be adjusted specifically during the experiment to meet specific experimental requirements. For example, some areas may require a stronger spring constant to cope with higher loads, while other areas may require a lower spring constant to slow down the speed or intensity of the applied load.

[0090] In any of the above embodiments, the experimental material includes multiple reflective particles, and water-conducting gaps are formed between the reflective particles; the flexible block 12 corresponds to multiple reflective particles along the direction of movement.

[0091] In this embodiment, the primary function of the reflective particles is as a fundamental component of the experimental material. They not only contribute to the mechanical response during the experiment but also facilitate the observation of the experimental material's behavior through the signal detection system of the monitoring unit. The surface of the reflective particles is covered with a special reflective material, enabling them to reflect clear signals under specific light sources. The particles are connected by tiny water-conducting gaps, a design that mimics the porous structure of real natural materials (such as sand, soil particles, etc.). During the experiment, these gaps not only allow fluids (such as water or experimental liquids) to flow between the particles but also influence the particles' mechanical response. Fluid flow can generate hydrodynamic interactions between the particles, altering the mutual forces between them and thus affecting the mechanical properties of the entire system and the experimental results.

[0092] Water-conducting gaps allow liquids or other fluids to flow between particles, simulating the fluid transport process through pores in real materials. This fluid flow not only helps maintain the mechanical equilibrium between particles but also allows for the simulation of various mechanical behaviors in experiments, such as shearing, friction, and interparticle interactions. Secondly, water-conducting gaps facilitate the precise measurement of the dynamic response of particulate materials in liquids. During stress loading, fluid flow is closely related to the mechanical response of particles; factors such as gap size and flow velocity affect the stress distribution between particles. By measuring and controlling these factors, researchers can conduct in-depth analysis of particle behavior in fluid environments.

[0093] The flexible block 12 is connected to the load application end via 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 slight deformation or displacement of the particles. Since the flexible block 12 contacts multiple reflective particles along the direction of movement during load application, this contact directly affects the movement and deformation of the reflective particles, thus affecting the measurement and recording of mechanical behavior in the experiment. The reflective particles feed back the mechanical forces they experience to the monitoring system in real time through the reflection signals on their surfaces.

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

[0095] The optical signal is acquired in the form of photoelastic fringes, and the image data containing the photoelastic fringes is used as the output of the parameter visualization mechanical experimental device.

[0096] In this embodiment, during the experiment, the light source emits a light signal through the loading section, and the light transmittance ensures that the light signal can pass smoothly through the experimental object or reflective particles without obstruction, and ultimately reach the monitoring system. This material selection ensures efficient transmission and accurate reflection of the light signal, facilitating the acquisition of the structural response and changes of the experimental object. The light-transmitting material not only allows the light signal to pass through but also optimizes the stability of the experimental environment through its transparency and optical properties. It effectively reduces the influence of external light sources, ensuring that the intensity and quality of the emitted light signal are not disturbed, thus making the experimental data more accurate and reliable. Its high transparency also allows the system to clearly observe the formation and change process of photoelastic fringes, providing clearly visible experimental results for further mechanical analysis. In the monitoring signal, the acquisition of the light signal is a crucial part. The light signal changes due to the deformation, displacement, and stress transmission of the experimental object, and this change manifests as photoelastic fringes. Photoelastic fringes are a type of visible interference fringe pattern formed by the refraction, reflection, or scattering effects of light passing through a stressed or deformed material. This stripe pattern directly reflects the stress and deformation of the material, exhibiting very high precision and discernibility. When the experimental object or reflective particles deform under external stress, the light-transmitting material transmits the signal from the light source to the experimental object. The light signal changes as it passes through the deformed area, ultimately forming unique photoelastic stripes. These stripes reflect the internal stress distribution, degree of deformation, and strain state of the material, forming the basis for acquiring mechanical data in optical monitoring.

[0097] Photoelastic fringes, acquired through optical signals, allow for precise observation of structural changes in experimental objects under different stress states. These fringes are more than just visual interference patterns; they represent the distribution of internal stress, interparticle mechanical responses, and material deformation. The position, density, shape, and orientation of each photoelastic fringe accurately reflect the deformation of the experimental object, stress concentration areas, and potential force chain transmission paths. These fringe patterns are captured by cameras or other sensors in the monitoring system and processed and analyzed using specialized software. By calculating and comparing changes in the photoelastic fringes, researchers can obtain visualized data on the stress state at each stage, the force changes in the material, and the internal mechanical behavior of the system. This data not only provides an intuitive basis for understanding the mechanical response of experimental objects under different loading conditions but also offers a scientific basis for optimizing material design and applications.

[0098] Furthermore, the loading unit includes two interlocking transparent water tank plates 7. Grooves are formed on the longitudinally opposite surfaces of the transparent water tank plates 7, and the two grooves combine to form a loading cavity. The transparent water tank plates 7 are placed in the center of the visualization loading mechanism and are mounted to the upper part of the support plate 6 by four pins located around the perimeter. The support plate and the loading unit together form an experimental platform, and the plane of interest for the experimental platform is the transverse xy-plane.

[0099] As described above, the structural design of the transparent water tank plate 7 is meticulously crafted according to experimental requirements. Each transparent water tank plate 7 has grooves on its longitudinally opposite surfaces. These two grooves cooperate during the assembly of the loading section to form a loading cavity. As the core part of the loading section, the loading cavity's main function is to accommodate the experimental object and provide sufficient space for applying loads. During the experiment, the loading cavity is not merely a container but also undertakes multiple tasks such as bearing, protecting, and transferring loads. By accommodating the experimental object, the loading cavity provides the necessary space for applying stress and monitoring structural changes in the object. The grooves in the transparent water tank plate 7 not only provide physical space for the object but also, through reasonable groove shapes and configurations, optimize the deformation performance of the experimental object under stress. The shape and size design of each groove affects the mechanical response of the water tank plate and the stability of the experimental object.

[0100] The transparent water bath 7 is positioned at the center of the visualization loading mechanism, making it the core conductor of optical signals during the experiment. Because the water bath is made of transparent material, the stress state of the experimental object can be visually presented during loading. The loading cavity, through the transparent water bath 7, provides a clearly visible space for the experimenters, allowing direct observation of the mechanical response and minute changes of the experimental object under different loading conditions. Furthermore, the installation position of the transparent water bath 7 is crucial; it is mounted to the upper part of the support plate 6 using four pins located around its perimeter. These pins ensure the stability and precise positioning of the transparent water bath 7. The tight structural connection of the pins prevents displacement or loosening of the transparent water bath 7 during the experiment, thus ensuring the accuracy and stability of the experimental data. The support plate 6, acting as a support device, firmly fixes the transparent water bath 7 to the center of the visualization loading mechanism, providing a stable platform for loading and monitoring.

[0101] The grooves in the transparent water tank plate 7 form a loading cavity, which accommodates the experimental object and provides it with loading space. In this space, the experimental object can undergo deformation or response under stress.

[0102] Furthermore, the water guiding channel includes an injection channel 701 and a corresponding drainage channel 702 located at both ends of the transparent water tank plate 7.

[0103] As described above, the injection channel 701 is located at one end of the transparent water tank plate 7. Its main function is to change the amount of liquid in the loading chamber through liquid injection, thereby regulating the environmental pressure of the experimental object. By controlling the opening and closing of the injection channel 701, the experimenter can precisely adjust the flow rate and initial pressure of the liquid entering the loading chamber. The design of the injection channel 701 ensures that liquid can continuously flow into the experimental chamber from the outside and interact with the experimental object inside the loading chamber. The size, shape, and inlet position of the injection channel 701 are designed with consideration for 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 allows for the observation and recording of the dynamic response of the experimental object under different stress states by adjusting the amount of liquid.

[0104] Opposite to the injection channel 701, the drainage channel 702 is located at the other end of the transparent water tank plate 7. Its main function is to allow liquid to drain from the loading chamber, thereby controlling the amount of liquid and its pressure changes within the chamber. The drainage channel 702 ensures bidirectional controllability of liquid flow during the experiment. Through the drainage channel 702, experimenters can precisely control the liquid discharge rate and pressure changes when applying loads or adjusting experimental conditions, avoiding excessive or insufficient liquid accumulation, thus ensuring the stability of the experimental environment. The drainage channel 702 not only serves to drain liquid but also helps maintain the balance of the experimental environment. For example, under certain experimental conditions, it may be necessary to reduce the pressure within the loading chamber by draining liquid, or to remove excess liquid to accommodate the deformation of the experimental object. The design of the drainage channel 702, in conjunction with the injection channel 701, achieves precise control of the amount of liquid within the loading chamber, enabling accurate capture and analysis of the deformation or response of the experimental object under different stress states. The synergistic effect between the injection channel 701 and the drainage channel 702 is key to the precise control of liquid pressure and experimental environment in this experimental apparatus. By simultaneously operating these two channels, researchers can precisely control the liquid environment surrounding the experimental object, allowing for adjustments to liquid flow and pressure changes within a precise range under varying stresses. For example, during the experiment, a certain amount of liquid is injected into the loading chamber through the injection channel 701, increasing the liquid pressure within the chamber; while excess liquid is drained through the drainage channel 702, reducing the liquid pressure or restoring a certain liquid equilibrium state. The synergistic effect of the two channels allows changes in the liquid environment to adapt to different experimental needs, while avoiding the impact of uneven liquid flow or excessive pressure fluctuations on experimental results. In mechanical experiments, the injection and drainage of liquid directly affect the stress state of the experimental object. The coordinated operation of the injection and drainage channels 702 ensures the controllability of liquid flow and keeps the influence of the liquid environment on the experimental object within a preset range.

[0105] In any of the above embodiments, the loading unit 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 arranged sequentially from bottom to top on the lower support 1, and the receiving end includes a quarter-wave plate, an analyzer, and a camera arranged sequentially from bottom to top on the upper support 3. The light source uses a polarizer to form plane-polarized light, a quarter-wave plate to form a circularly polarized field, an analyzer to filter directionally polarized light, and a camera to acquire images. The polarizer and camera are respectively arranged on opposite sides of the visualization loading device. Quarter-wave plates are 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 sequentially along the polarizer, quarter-wave plate, visualization loading device, quarter-wave plate, analyzer, and camera, ensuring that the light emitted by the light source propagates to the particles inside the visualization loading device.

[0107] As described above, the transmitting end includes a light source, a polarizer, and a quarter-wave plate arranged sequentially from bottom to top on the lower support 1. The function of these components is closely related to their arrangement order, and through precise optical coordination, they 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, responsible for emitting initial light. In this device, the role of the light source is not merely to emit light, but also to provide a beam of light with sufficient intensity and stability to ensure that subsequent optical elements can effectively modulate and process the beam. Specifically, the light emitted by the light source is guided through the subsequent polarizing elements to form plane-polarized light.

[0109] The polarizer, positioned between the light source and the quarter-wave plate, primarily converts the natural light emitted from the light source into plane-polarized light. By adjusting the angle of the polarizer, the direction of the plane-polarized light can be ensured to meet the experimental design requirements. The introduction of plane-polarized light provides the foundation for subsequent polarization modulation.

[0110] The quarter-wave plate at the transmitting end is located after the polarizer. Its function is to convert plane-polarized light into circularly polarized light. Circularly polarized light has a specific direction of rotation, which allows for better transmission of 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 circularly polarized field be formed, enabling the response of the particles under different stress states in the experiment to be transmitted more accurately to the receiving end.

[0111] The receiver consists of a quarter-wave plate, an analyzer, and a camera, arranged sequentially from bottom to top on the upper support 3. The receiver's design is closely linked to the optical path of the transmitter, and its main function is to capture the changing light signal after passing through the experimental material (particulate material sample) and convert it into data that can be analyzed.

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

[0113] The analyzer, located behind the quarter-wave plate, filters and selects polarized light in a specific direction. Its placement ensures that only the required light signals are transmitted to the camera, avoiding signal interference and improving the signal-to-noise ratio.

[0114] The camera, located at the end of the receiver, is responsible for converting the light signal obtained after passing through the analyzer into visualized image data. The image data captured by the camera can be further converted into visualized parameters such as photoelastic fringes. These data are directly used as the output of the experimental setup, 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 using the parametric visualization mechanics experimental apparatus according to any of the above embodiments. In some embodiments of the present invention, the experimental method includes the following steps:

[0116] S101, Test Preparation Phase, includes:

[0117] Before applying the load, a large number of small cylindrical photoelastic particles are placed into a transparent water tank 7 using slender tweezers. Then, water or other fluids are injected through the injection channel 701 via an external microfluidic pump, and the water or other fluids discharged from the drainage channel 702 are collected by an external collection tank. Next, the light source is turned on, and the light emitted by the light source is directed to propagate sequentially along the polarizer, quarter-wave plate, visualization loading mechanism, quarter-wave plate, analyzer, and camera, ensuring that the light emitted by the light source propagates to the millimeter-sized particles.

[0118] S102, the lateral load application stage, 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 locked between the upper clamping plate 404 and the lower clamping plate 405 by the frustum-shaped locking block 414. Then, the second stepper motor 402 pushes the front push plate 408, which drives the push rod 407 forward, thereby moving the rear push plate 409 forward. The spring 13 is compressed through the sleeve, and the push rod 407 is fixed to the bracket by bolts, thereby fixing the compression of the spring 13 and storing the propulsive force as the elastic force of the spring 13. Next, 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, which drives the lower clamping plate 405 downward. Then, the guide rod clamped between the upper and lower clamping plates 405 moves forward together, slowly releasing the load, thereby applying lateral confining pressure.

[0120] S103, the uniaxial compressive load application stage, includes:

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

[0122] Following the above steps, images of the loading process are captured by a camera and processed by computer software, allowing for a direct observation of the changes in contact stress, the formation process of shear bands, and the distribution and orientation of force chains within the granular material.

[0123] This invention provides an experimental method that, through precise control of load application and mechanical parameter acquisition at multiple stages, enables the study of the mechanical behavior of particulate materials in a realistic fluid-structure interaction environment, particularly focusing on 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 analyzed and visualized in depth, thus providing strong experimental support and theoretical basis for related research fields.

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

[0125] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A parameter visualization mechanical experimental device for fluid-structure interaction, characterized in that, include: A stress loading mechanism, which has an experimental platform and multiple load application ends; The load application ends are arranged circumferentially on the experimental platform, and each load application end can move independently to form multiple stress states in the center of the experimental platform. The motion direction of each load application end is a single-axis direction, and all the motion directions are located in a plane of the experimental platform; A loading section is located in the center of the experimental platform; the interior of the loading section has a loading cavity for accommodating the experimental object, and the load application end extends from the outside of the loading section to the loading cavity; A water channel is provided on the side of the loading part along a guiding direction; the water channel connects to the loading cavity, and the water channel injects and / or extracts experimental water from the experimental object through the loading cavity; the movement direction of at least one of the load application ends is the same as the guiding direction; The monitoring unit has a transmitter and a receiver; the transmitter 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 receiver after passing through the experimental object, and acquires the structural morphology of the experimental object under the current stress state, as well as observes the interaction between the fluid and solid particles in real time. At least one flexible block is provided, and the flexible block is connected to the load application end; before the load application end moves, the sidewall of the flexible block is in contact with the experimental object; the flexible block is connected to the load application end through a buffer mechanism to maintain the position of the flexible block in the loading cavity when the load application end moves; the buffer mechanism includes: a first rod connected to the load application end along the movement direction, and the first rod is hollow; the sidewall of the flexible block is connected to the end face of the first rod through a spring; a second rod is concentrically arranged with the first rod, and the second rod and the first rod can move relative to each other along the movement direction; one end of the second rod is connected to the flexible block, and the other end of the second rod is detachably mounted on the experimental platform; The load-applying end includes a first stepper motor, a second stepper motor, a central bearing, an upper clamping plate, a lower clamping plate, a frame plate, a push rod, a front push plate, a rear push plate, and a frustum-shaped locking block. The end of the second rod is connected to the flexible block, and its tail is clamped between the upper and lower clamping plates by the frustum-shaped locking block. A spring is sleeved on the second rod outside the section between the flexible block and the first rod, and a first rod slightly larger than the second rod is sleeved on the section between the spring and the push plate. The upper clamping plate is connected to the first stepper motor and is mounted on the frame plate together with the lower clamping plate. The frame plate is fixed to the support plate; the second stepper motor pushes the front push plate, which drives the push rod forward, thereby moving the rear push plate forward. The first rod compresses the spring, and the push rod is fixed to the bracket with bolts, thus fixing the spring compression and storing the propulsion force as spring force. Then, under the control of the first stepper motor, the upper clamping plate moves up, and at the same time, the central bearing rotates, driving the lower clamping plate down. The second rod clamped between the upper and lower clamping plates moves forward together, slowly releasing the load and thus applying lateral confining pressure.

2. The parameter visualization mechanical experimental apparatus according to claim 1, characterized in that, The second rod is sleeved on the circumferential sidewall outside the first rod, 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.

3. The parameter visualization mechanical experimental device according to claim 2, characterized in that, When the experimental object is under the stress state, the following conditions apply: Scenario 1: Close the water channel and maintain the experimental water volume in the loading cavity to adjust the water pressure value; In scenario two, the water channel is opened and the amount of experimental water in the loading chamber is changed to adjust the pressure value.

4. The parameter visualization mechanical experimental device according to claim 1, characterized in that, The buffer mechanism is provided at least one on the same load application end, and all springs corresponding to the same load application end have the same / or different elastic coefficients.

5. The parameter visualization mechanical experimental apparatus according to claim 1, characterized in that, The experimental material includes multiple reflective particles, and water-conducting gaps are formed between the reflective particles; the flexible block corresponds to multiple reflective particles along the direction of movement.

6. The parameter visualization mechanical experimental apparatus according to claim 5, characterized in that, The loading part is made of a light-transmitting material, and the monitoring signal includes a light signal; The optical signal acquires a structural morphology of photoelastic stripes, and the image data containing the photoelastic stripes is used as the output of the parameter visualization mechanical experimental device.

7. The parameter visualization mechanical experimental apparatus according to claim 1, characterized in that, The loading part 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.

Images