A sample preparation device and method for precisely regulating the crystallinity of a photoelastic sample

Abstract

The present application relates to the field of photoelastic test sample preparation, especially to a device and method for precisely regulating the crystallinity of photoelastic test sample. The device comprises a sample frame, a vertical loading component, a horizontal vibration component, a pneumatic disturbance component and a crystallinity identification system. The vertical loading component comprises a vertical servo motor and a porous air-permeable plate, which is movably arranged at the top opening of the cavity. The horizontal vibration component comprises a horizontal vibration motor and a bearing base, which is movably connected with the counterforce frame. The pneumatic disturbance component comprises an ion fan and an air flow delivery and control pipeline, which communicates the ion fan with the cavity. The crystallinity identification system comprises a light source, a polarizer, a cavity, an analyzer, a camera and a calculation unit arranged along the optical axis in sequence. The present application combines vibration and pneumatic disturbance, and combines online identification feedback, so as to realize the precise regulation of the crystallinity of photoelastic test sample.

Description

Technical Field

[0001] This invention relates to the field of photoelastic test sample preparation technology, and in particular to a sample preparation device and method for precisely controlling the crystallinity of photoelastic samples. Background Technology

[0002] Photoelasticity experiments are an important experimental method for exploring the micromechanical mechanisms of particulate materials. They utilize the stress birefringence effect of photoelastic materials, and through the interference fringes generated when polarized light passes through stressed particles, they enable the visualization and quantitative characterization of contact force chains and stress distribution within the particulate system.

[0003] Photoelastic experiments typically use transparent particles of a single size as model materials. These particles possess high geometric symmetry and size uniformity. When naturally packed or subjected to external excitation, the particles easily interlock and arrange themselves in an ordered manner, a phenomenon known as "crystallization." The degree of crystallinity directly affects the macroscopic mechanical response of the particle system, such as strength, stiffness, and dilatation. Therefore, preparing photoelastic samples with a specified degree of crystallinity is a prerequisite for conducting quantitative research on the impact of crystallinity on mechanical properties.

[0004] Currently, the preparation of photoelastic samples mainly relies on random scattering, manual assembly, or simple tapping and vibration. When it is necessary to reduce crystallinity, operators rely on experience to tap or move the particles to disrupt their arrangement. This method cannot precisely control the degree of disruption and easily leads to non-uniform phenomena such as stratification and local agglomeration within the sample. When it is necessary to increase crystallinity, simple vibration or compaction is insufficient to achieve a stable and ordered packing state for the particle system. Overall, existing technologies lack sample preparation devices that can continuously, accurately, and repeatedly control the crystallinity of photoelastic particle systems.

[0005] Therefore, there is an urgent need for an automated sample preparation device that integrates multiple control methods and a real-time feedback system to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a sample preparation device and method for precisely controlling the crystallinity of photoelastic samples, addressing the shortcomings of the aforementioned background technology.

[0007] To achieve the above objectives, the present invention provides a sample preparation device for precisely controlling the crystallinity of a photoelastic sample, comprising: The sample frame has a cavity for accommodating photoelastic particles; A vertical loading component includes a reaction frame and a vertical servo motor; the reaction frame is disposed outside the sample frame, the vertical servo motor is disposed above the sample frame, and the output end of the vertical servo motor is provided with a loading plate, which is movably disposed at the top opening of the cavity; A horizontal vibration component includes a support base and a horizontal vibration motor; the support base is connected to the reaction frame, the sample frame is disposed on the support base, and the horizontal vibration motor is connected to the support base to apply horizontal vibration to the support base; The pneumatic disturbance component includes an ion fan for generating positive and negative charged ions. The ion fan is connected to the cavity through an airflow delivery and control pipeline, and the porous vent plate constitutes the exhaust port of the cavity. The crystallinity identification system includes a camera, a light source, a polarizer, an analyzer, and a computing unit; the light source, polarizer, cavity, analyzer, and camera are arranged sequentially along the optical axis; the computing unit is connected to the camera to acquire particle images and calculate crystallinity, and adjusts the operating parameters of the vertical servo motor, the horizontal vibration motor, and the ion fan according to the crystallinity.

[0008] Preferably, the sample frame has a top opening and a side opening, the top opening and the side opening are interconnected, and a detachable clamp is provided at the side opening.

[0009] Preferably, the loading plate includes a vertical loading plate and a porous ventilated plate, and the output end of the vertical servo motor is detachably connected to the vertical loading plate or the porous ventilated plate via a vertical force transmission rod.

[0010] Preferably, the porous ventilated plate has multiple through holes, the diameter of which is smaller than the minimum diameter of the photoelastic particles; a preset gap exists between the lower surface of the porous ventilated plate and the upper surface of the photoelastic particles inside the cavity.

[0011] Preferably, the support base is provided with rollers at its bottom, and the reaction frame is provided with corresponding roller fixing grooves, with the rollers embedded in the roller fixing grooves; it also includes a position holding mechanism, which has a fixed state in which the support base is fixed relative to the reaction frame, and an active state in which the support base is allowed to move relative to the reaction frame.

[0012] Preferably, the airflow delivery and control pipeline includes a first air inlet pipeline, one end of which is connected to the ion blower, and the other end is connected to one end of a second pipeline through an airflow control valve. The other end of the second pipeline branches into multiple branches, and each branch is connected to a third air inlet pipeline. The third air inlet pipeline passes through the bottom and side wall of the sample frame and enters the cavity.

[0013] Preferably, the ion fan is a corona discharge ion generator, and the ions generated by the corona discharge ion generator are carried by a carrier airflow and introduced into the cavity through the airflow delivery and control pipeline.

[0014] Preferably, the computing unit is also electrically connected to a vertical servo motor, a horizontal vibration motor, and an ion fan.

[0015] The present invention also provides a sample preparation method using the above-mentioned sample preparation device for precisely controlling the crystallinity of photoelastic samples, comprising the following steps: The photoelastic particles are loaded into the cavity of the sample frame; The crystallinity identification system is activated to acquire particle images and calculate the current crystallinity. Compare the current crystallinity with the target crystallinity; If the current crystallinity is lower than the target crystallinity, activate the horizontal vibration component to increase the crystallinity of the photoelastic sample; If the current crystallinity is higher than the target crystallinity, activate the pneumatic disturbance component to reduce the crystallinity of the photoelastic sample; Repeat the comparison, increase crystallinity, and decrease crystallinity operations until the current crystallinity reaches the target crystallinity.

[0016] The above-described solution of the present invention has the following beneficial effects: (1) This invention integrates two control methods, horizontal vibration and pneumatic disturbance, into the same device. Horizontal vibration drives the entire sample frame to reciprocate horizontally through the support base, causing the particles to slide, roll, and rearrange under the action of inertial force; pneumatic disturbance generates airflow through an ion fan, which is injected from multiple points on the side wall of the cavity through multiple branch pipelines, disturbing the particles and breaking the ordered structure. The two methods complement each other, realizing precise control of the crystallinity of the photoelastic sample.

[0017] (2) This invention introduces a photoelastic crystallinity recognition system as an online feedback loop. The light emitted by the light source is converted into polarized light by a polarizer, and after penetrating the particles in the sample frame, the photoelastic stripe image is captured by a camera through an analyzer. The calculation unit calculates the current crystallinity through an image processing algorithm and compares it with the target crystallinity. Then, it controls the start and stop of the corresponding control components and the parameters, forming a closed-loop control of "recognition-judgment-control-re-recognition", which automates the sample preparation process and makes the results accurately repeatable.

[0018] (3) By adding a horizontal driving device and a horizontal loading plate, the present invention can be easily expanded into a biaxial loading test system, so that sample preparation and mechanical testing can be completed continuously on the same device, avoiding the disturbance caused by sample transfer, and significantly improving experimental efficiency and data reliability.

[0019] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the sample preparation device in this invention; Figure 2 for Figure 1Schematic diagram of the cross-sectional structure along the AA direction; Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure in the middle BB direction; Figure 4 This is a schematic diagram of the exploded structure of the sample frame in this invention; Figure 5 This is a schematic diagram of the structure of the support base in this invention; Figure 6 This is a schematic diagram of the reaction frame base plate in this invention; Figure 7 This is a schematic diagram of the device of the present invention extended to a uniaxial compression test; Figure 8 This is a schematic diagram of the device of the present invention extended to a biaxial compression test; Figure 9 for Figure 7 Schematic diagram of the vertical loading plate; Figure 10 for Figure 7 Schematic diagram of the structure of the horizontal loading plate; Figure 11 This is a schematic diagram of the automated sample preparation process in this invention.

[0021] Explanation of reference numerals in the attached figures 1. Sample frame; 101. First side plate; 102. Second side plate; 103. Clamping plate; 2. Vertical loading components; 201. Reaction frame; 202. Vertical servo motor; 203. Vertical force transmission rod; 204. Perforated ventilated plate; 3. Horizontal vibration components; 301. Support base; 302. Horizontal vibration motor; 303. Rollers; 4. Pneumatic disturbance components; 401. Ionizing fan; 402. Airflow control valve; 403. First air inlet pipe; 404. Second pipe; 405. Third air inlet pipe; 5. Horizontal drive device; 501. Horizontal servo motor; 502. Horizontal loading plate; 503. Horizontal force transmission rod; 6. Vertical loading plate. Detailed Implementation

[0022] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example 1 like Figures 1 to 6 As shown, embodiments of the present invention provide a sample preparation device for precisely controlling the crystallinity of a photoelastic sample, mainly including a sample frame 1, a vertical loading component 2, a horizontal vibration component 3, a pneumatic disturbance component 4, and a crystallinity identification system. The vertical loading component 2 can apply vertical pressure to the photoelastic particles in the sample frame 1 for loading during the experiment and can promote the photoelastic particles to tend towards orderly dense packing during the sample preparation stage; the horizontal vibration component 3 is set on one side of the sample frame 1 to drive the entire sample frame 1 to reciprocate horizontally, so that the photoelastic particles are arranged in an orderly manner; the airflow generated by the pneumatic disturbance component 4 is injected from multiple points on the bottom and side walls of the sample frame 1 through multiple branch pipelines, disturbing the photoelastic particles and breaking the orderly structure; the crystallinity identification system is used to detect the crystallinity of the photoelastic particles.

[0026] In this embodiment, the sample frame 1 is made of transparent acrylic sheet, including a first side plate 101 and a second side plate 102. Both the first side plate 101 and the second side plate 102 are rectangular plates. The first side plate 101 and the second side plate 102 are provided with connecting holes along their side lengths. The first side plate 101 and the second side plate 102 are arranged side by side with intervals. An L-shaped protrusion is integrally formed on the side of the second side plate 102 facing the first side plate 101. The L-shaped protrusion is also provided with connecting holes. The first side plate 101 and the second side plate 102 are connected by fixing bolts passing through the connecting holes to form the sample frame 1. The sample frame 1 has a photoelastic particle receiving cavity with a top opening and a side opening. A clamping plate 103 is detachably connected to the side opening. The clamping plate 103 is provided with connecting holes along its length direction. The clamping plate 103 is clamped between the first side plate 101 and the second side plate 102 and is connected to the first side plate 101 and the second side plate 102 as a whole by fixing bolts, so that the photoelastic particle receiving cavity only has a top opening. The gaps between the first side plate 101, the second side plate 102, and the clamping plate 103 can be filled with sealant. The photoelastic particles used are made of transparent materials with stress birefringence effect, such as polycarbonate or epoxy resin.

[0027] In this embodiment, the vertical loading component 2 includes a reaction frame 201, which spans the outside of the sample frame 1 to provide reaction force support for loading. A vertical servo motor 202 is provided at the center of the crossbeam of the reaction frame 201. The telescopic end of the vertical servo motor 202 faces the cavity of the sample frame 1, and the end is detachably connected to a loading plate through a vertical force transmission rod 203. The outer dimensions of the loading plate match the cross-section of the cavity, and it can move up and down in the top opening of the cavity under the drive of the vertical servo motor 202.

[0028] Furthermore, the loading plate includes a vertical loading plate 6 and a porous vent plate 204. The vertical loading plate 6 is used when performing compression tests, and the porous vent plate 204 is used when the aerodynamic disturbance component 4 is working.

[0029] In this embodiment, the horizontal vibration component 3 includes a support base 301 and a horizontal vibration motor 302, with the sample frame 1 fixed to the support base 301. Rollers 303 are mounted on the bottom of the support base 301, and corresponding roller fixing grooves are provided on the bottom plate of the reaction frame 201. The rollers 303 are embedded in the roller fixing grooves, allowing the support base 301 to reciprocate horizontally. The output end of the horizontal vibration motor 302 is connected to the support base 301 via a horizontal vibration transmission rod, transmitting horizontal vibration to the sample frame 1.

[0030] Furthermore, it also includes a position holding mechanism, which is a locking pin that can be inserted into the corresponding snap-fit ​​groove on the base plate of the reaction frame 201. When the locking pin is inserted into the snap-fit ​​groove, the bearing base 301 is locked to the reaction frame 201 and is in a fixed state; when the locking pin is pulled out, the bearing base 301 can move relative to the reaction frame 201 and is in a movable state.

[0031] In this embodiment, the pneumatic disturbance component 4 includes an ion fan 401, which is preferably a corona discharge ion generator. The corona discharge ion generator includes a positive ion emitting needle and a negative ion emitting needle, and is equipped with an ion concentration adjustment unit. The ion concentration adjustment unit is electrically connected to a calculation unit to adjust the ion emission concentration according to the difference between the current crystallinity and the target crystallinity. The positive and negative charged ions generated by the corona discharge ion generator are carried by the carrier airflow and introduced into the cavity through the airflow delivery and control pipeline to eliminate the static electricity on the surface of the photoelastic particles and disturb the photoelastic particles. The airflow delivery and control pipeline includes a first air inlet pipeline 403, an airflow control valve 402, a second pipeline 404, and multiple third air inlet pipelines 405. One end of the first air inlet pipe 403 is connected to the ion blower 401, and the other end is connected to one end of the second pipe 404 through the airflow control valve 402; the other end of the second pipe 404 branches into multiple branches; multiple third air inlet pipes 405 are arranged at the bottom and side walls of the sample frame 1, one end of each third air inlet pipe 405 is connected to a branch, and the other end leads into the cavity. A porous vent plate 204 is arranged at the top opening of the sample frame 1, forming the exhaust port for the airflow in the cavity. The airflow is injected from multiple points at the bottom and side walls of the sample frame 1, passes through the gaps between particles, and is discharged from the top porous vent plate 204. The positively and negatively charged ion airflow generated by this ion generator enters the cavity and can neutralize the static charge generated by the particles due to mutual friction, effectively preventing the particles from agglomerating due to electrostatic adsorption, thereby reducing the crystallinity.

[0032] Furthermore, the diameter of the through holes in all air inlet pipes and the porous vent plate 204 is smaller than the minimum diameter of the photoelastic particles to prevent particles from entering the pipes and causing blockage. A preset gap is left between the lower surface of the porous vent plate 204 and the upper surface of the particles in the cavity. This preset gap is used to provide a uniform discharge channel for the airflow, prevent particles from clogging the through holes of the porous vent plate 204, and at the same time provide space for the local movement of particles under airflow disturbance, thereby increasing crystallinity and reducing efficiency.

[0033] In this embodiment, the crystallinity identification system includes a camera, a light source, a polarizer, an analyzer, and a computing unit. The camera is a high-resolution camera, the light source is a monochromatic LED surface light source, and the computing unit is a computer. The light source, polarizer, cavity containing the sample, analyzer, and camera are arranged sequentially along an optical axis, forming a transmission-type photoelastic optical path. The light source provides monochromatic light, which is converted into plane-polarized light by the polarizer. After passing through the stress particles in the sample frame 1, a phase delay is generated, and after passing through the analyzer, an interference fringe image is formed, which is acquired by the camera and transmitted to the computing unit. The computing unit runs an image processing algorithm to locate the center position of each particle, calculate quantitative indicators such as bond order parameters, and obtain the crystallinity of the current sample.

[0034] Furthermore, the vertical servo motor 202, the horizontal vibration motor 302, the ion fan 401, and the airflow control valve 402 are all electrically connected to the computing unit. Based on the comparison between the current crystallinity and the preset target crystallinity, the computing unit automatically controls the working status and operating parameters of each component.

[0035] This embodiment also provides a method for preparing highly crystalline samples using the above-described apparatus.

[0036] First, the photoelastic particles are loaded into the cavity of the sample frame 1. The position holding mechanism is switched to the active state, allowing the support base 301 to move freely horizontally. The computing unit controls the horizontal vibration motor 302 to operate at a preset frequency and amplitude, driving the support base 301 and the entire sample frame 1 to vibrate horizontally through the vibration transmission component. Under the action of inertial force, the particles overcome mutual friction, rearrange themselves, and tend to accumulate in an orderly manner.

[0037] After the preset vibration duration, the horizontal vibration motor 302 is paused. The position holding mechanism is switched to the locked state to fix the sample frame 1. The calculation unit controls the vertical servo motor 202 to start, which drives the porous air-permeable plate 204 to move downward through the vertical force transmission rod 203, applying a preset vertical load to the particle system to further stabilize the orderly arrangement of the particles.

[0038] The crystallinity recognition system is activated, and the camera captures a photoelastic stripe image of the current particle arrangement. The calculation unit calculates the current crystallinity. If the crystallinity reaches the preset target value, the sample preparation is complete; if not, the above steps are repeated until the crystallinity approaches the target value.

[0039] This embodiment also provides a method for preparing low-crystallinity samples.

[0040] After loading the photoelastic particles into the cavity of sample frame 1, ensure that the position holding mechanism is locked, and sample frame 1 is fixed. Place the porous vent plate 204 at the predetermined position at the top opening of the cavity.

[0041] The computing unit starts the ion fan 401 and opens the airflow control valve 402. The electrically charged current generated by the ion fan 401 flows through the first inlet pipe 403, the airflow control valve 402, and branches of the second pipe 404, and is injected into the cavity from multiple points through multiple third inlet pipes 405 arranged at the bottom and side walls of the sample frame 1. The airflow disturbs the particle system, breaking its original ordered structure, while the ion charge neutralizes the static electricity between particles, preventing agglomeration.

[0042] After the preset disturbance time, the pneumatic disturbance component 4 is turned off, and the particles are allowed to stabilize. The crystallinity recognition system is activated, the camera captures an image of the particle arrangement, and the calculation unit calculates the current crystallinity. If the crystallinity drops to the preset target value, the sample preparation is complete; if it is not reached, the pneumatic disturbance is restarted, and the operation is repeated until the target is met.

[0043] This embodiment also provides an automated sample preparation process based on computing unit control, such as... Figure 11 As shown, it includes the following steps: S1. Load the photoelastic particles into the cavity of the sample frame 1.

[0044] S2. Start the crystallinity recognition system, the camera acquires particle images, and the computing unit calculates the current crystallinity.

[0045] S3. The calculation unit compares the current crystallinity with the preset target crystallinity to determine the direction and magnitude of the deviation.

[0046] S4. If the current crystallinity is lower than the target crystallinity, perform the crystallinity increase operation, switch the position holding mechanism to the active state, start the horizontal vibration motor 302 to perform horizontal vibration; then switch to the locking state, start the vertical servo motor 202 to apply vertical load.

[0047] S5. If the current crystallinity is higher than the target crystallinity, perform a crystallinity reduction operation: keep the position holding mechanism locked, start the ion fan 401, open the airflow control valve 402, and inject airflow disturbance particles.

[0048] S6. Repeat steps S2 to S5, and through a closed-loop iteration of “identification-judgment-regulation-re-identification”, gradually converge the crystallinity to the target value.

[0049] S7. When the measured crystallinity falls within the allowable error range of the target value, stop all control actions and complete the sample preparation.

[0050] Example 2 This embodiment demonstrates the extension of the apparatus in Embodiment 1 for biaxial testing.

[0051] like Figure 7As shown, after the sample preparation is completed, the porous air plate 204 can be replaced with a solid vertical loading plate 6, and the sample can be subjected to a uniaxial compression test using only the vertical servo motor 202.

[0052] like Figures 8 to 10 As shown, if a biaxial compression test is required, the clamping plate 103 of the specimen frame 1 is removed, and a horizontal drive device 5 is installed on that side. The horizontal drive device 5 includes a horizontal servo motor 501, which is fixed to the horizontal side of the specimen frame 1 via a reaction frame 201. Its output end is connected to a horizontal loading plate 502 via a horizontal force transmission rod 503. The horizontal loading plate 502 is placed between the first side plate 101 and the second side plate 102 and can move horizontally within the cavity. The horizontal servo motor 501 drives the horizontal loading plate 502 to apply a horizontal load to the specimen via the horizontal force transmission rod 503.

[0053] The vertical loading plate 6 has a first serrated section at one end near the horizontal loading plate 502, and the corresponding end of the horizontal loading plate 502 has a second serrated section that complements the first serrated section. During loading, the serrated sections of the two loading plates interlock, avoiding rigid contact and ensuring that both vertical and horizontal loads are effectively transferred to the particles. This extended method allows sample preparation and mechanical testing to be completed continuously on the same device, avoiding disturbances caused by sample transfer and significantly improving experimental efficiency and data reliability.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A sample preparation device for precisely controlling the crystallinity of a photoelastic sample, characterized in that, include: The sample frame has a cavity for accommodating photoelastic particles; A vertical loading component includes a reaction frame and a vertical servo motor; the reaction frame is disposed outside the sample frame, the vertical servo motor is disposed above the sample frame, and the output end of the vertical servo motor is provided with a loading plate, which is movably disposed at the top opening of the cavity; A horizontal vibration component includes a support base and a horizontal vibration motor; the support base is connected to the reaction frame, the sample frame is disposed on the support base, and the horizontal vibration motor is connected to the support base to apply horizontal vibration to the support base; The pneumatic disturbance component includes an ion fan for generating positive and negative charged ions. The ion fan is connected to the cavity through an airflow delivery and control pipeline, and the loading plate constitutes the exhaust port of the cavity. The crystallinity identification system includes a camera, a light source, a polarizer, an analyzer, and a computing unit; the light source, polarizer, cavity, analyzer, and camera are arranged sequentially along the optical axis; the computing unit is connected to the camera to acquire particle images and calculate crystallinity, and adjusts the operating parameters of the vertical servo motor, the horizontal vibration motor, and the ion fan according to the crystallinity.

2. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 1, characterized in that, The sample frame has a top opening and a side opening, which are connected to each other. A detachable clamp is provided at the side opening.

3. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 1, characterized in that, The loading plate includes a vertical loading plate and a porous ventilated plate. The output end of the vertical servo motor is detachably connected to the vertical loading plate or the porous ventilated plate via a vertical force transmission rod.

4. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 3, characterized in that, The porous ventilated plate has multiple through holes, the diameter of which is smaller than the minimum diameter of the photoelastic particles; there is a preset gap between the lower surface of the porous ventilated plate and the upper surface of the photoelastic particles inside the cavity.

5. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 1, characterized in that, The support base is provided with rollers at its bottom, and the reaction frame is provided with roller fixing grooves accordingly, with the rollers embedded in the roller fixing grooves; it also includes a position holding mechanism, which has a fixed state that fixes the support base relative to the reaction frame, and an active state that allows the support base to move relative to the reaction frame.

6. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 1, characterized in that, The airflow delivery and control pipeline includes a first air inlet pipeline. One end of the first air inlet pipeline is connected to the ion blower, and the other end is connected to one end of the second pipeline through an airflow control valve. The other end of the second pipeline branches into multiple branches, and each branch is connected to a third air inlet pipeline. The third air inlet pipeline passes through the bottom and side wall of the sample frame and enters the cavity.

7. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 1, characterized in that, The ion fan is a corona discharge ion generator. The ions generated by the corona discharge ion generator are carried by a carrier airflow and introduced into the cavity through the airflow delivery and control pipeline.

8. The sample preparation device for precisely controlling the crystallinity of photoelastic samples according to claim 1, characterized in that, The computing unit is also electrically connected to a vertical servo motor, a horizontal vibration motor, and an ion fan.

9. A sample preparation method based on the sample preparation apparatus for precisely controlling the crystallinity of a photoelastic sample as described in any one of claims 1-8, characterized in that, Includes the following steps: The photoelastic particles are loaded into the cavity of the sample frame; The crystallinity identification system is activated to acquire particle images and calculate the current crystallinity. Compare the current crystallinity with the target crystallinity; If the current crystallinity is lower than the target crystallinity, activate the horizontal vibration component to increase the crystallinity of the photoelastic sample; If the current crystallinity is higher than the target crystallinity, activate the pneumatic disturbance component to reduce the crystallinity of the photoelastic sample; Repeat the comparison, increase crystallinity, and decrease crystallinity operations until the current crystallinity reaches the target crystallinity.

Images