Artificial joint in-situ testing machine based on variable-curvature micro-channel clamp and use method of artificial joint in-situ testing machine

Abstract

The invention relates to the technical field of material mechanics testing equipment, in particular to an artificial joint in-situ testing machine based on a variable-curvature micro-channel clamp and a using method thereof.The artificial joint in-situ testing machine comprises a driving unit, a clamp testing unit and a moving unit which are arranged on a platform base, the driving unit is located on one side of the platform base, and the clamp testing unit is located on the other side of the platform base; the driving unit and the moving unit are connected through a gear transmission assembly, the moving unit is connected with a clamp assembly and a testing assembly of the clamp testing unit through a sliding block assembly, a liquid pool of the clamp testing unit is located in the center of the platform base, the clamp assembly is located in the liquid pool, and a temperature control assembly is further arranged in the liquid pool. By the adoption of the structure, the variable-curvature micro-channel with the semicircle and the arc combined is arranged in the flexible gasket, stress anisotropy is achieved, stress concentration is avoided through the semicircle micro-channel, and interaction between liquid medium flowing and a sample observation area is achieved through the arc micro-channel.

Description

Technical Field

[0001] The present invention relates to the technical field of material mechanics testing equipment, and in particular to an artificial joint in-situ testing machine based on a variable curvature micro-channel fixture and a use method thereof. Background Art

[0002] The in vivo service mechanical environment of artificial joints is complex, and the loads they are subjected to are dynamically changing in a periodic and multi-directional manner. The joint cavity in which they are located contains synovial fluid with various biological components, which has a certain viscosity and cushioning property, and continuously acts on the joint surface to affect the mechanical properties of the material. Given that the human body is in a "black box state", it is extremely difficult to conduct mechanical monitoring in vivo. In order to explore replacement materials with better performance, it is of practical significance to reproduce the actual service environment in vitro and conduct mechanical tests. Simulating the various mechanical loads that artificial joints are subjected to in actual service, such as pressure, friction, impact force, etc., while taking into account the lubricating effect of synovial fluid on joint movement and the chemical effect on the joint surface, can more comprehensively evaluate the mechanical properties, wear characteristics, durability and other performance indicators of artificial joints in complex liquid environments.

[0003] In addition, exploring the deformation mechanism of the microstructure of the material under service, such as grain deformation, dislocation movement, and grain boundary changes, is the key to revealing macroscopic deformation behavior and a direct way to obtain the mechanical properties of joint materials. In conventional mechanical experiments, the response of the microstructure is complex and rapid, and it is difficult to observe the evolution process in real time. After deformation, the material has "residual" traces of microstructural changes, such as dislocation distribution, density, and morphology. With the help of microscopic analysis methods such as scanning electron microscopy for characteristic analysis, researchers can reversely infer the evolution of the material's microstructure during the stress process and reveal the behavior of the microstructure in the mechanical process. However, the characterization of the cross-sectional microstructure in the above-mentioned test method is observed for a specific state and time, and the results obtained are not for the entire test period. It reflects the microstructural characteristics of a certain area under a specific state in the micro-area material test, and discontinuously shows the performance of the local microstructure. The dynamic evaluation of material performance lacks continuous characterization information, such as the dynamic evolution process of dislocations.

[0004] In-situ experiments combining mechanical testing with scanning electron microscopy (SEM) can explore the relationship between microstructure and mechanical properties. Among them, the use of high-resolution electron microscopes can observe the deformation process of grains and the trajectory of dislocation movement, and obtain structural characteristic images of materials under different load conditions at the micrometer and nanometer scales. The in-situ test bench can achieve different environmental conditions, such as temperature, humidity, atmosphere, etc., to reproduce the actual service environment, and then test the mechanical properties of the material to understand the mechanical properties of the material under different stress and strain conditions, such as strength, toughness, elastic modulus, etc. The combination of the two can observe the microstructural changes of the material in the actual service environment in real time, obtain the structural characteristics of a certain area of ​​the material in the dynamic state and at a specific time, continuously measure and characterize the micromechanical properties of the material, and deeply understand the dynamic evolution process of the mechanical properties and microstructure of the material.

[0005] In mechanical tests, due to the low precision of the loading equipment or the complex test design, the specimen will inevitably slip and experience temperature concentration, especially the contact surface between the clamping device and the specimen, which affects the mechanical observation results of the inspection area. In summary, the in-situ test of the micromechanical properties of artificial joints still needs to reproduce the actual service environment, use SEM for characterization observation, explore the deformation mechanism of the microstructure, and solve the stress concentration phenomenon, which is conducive to the accurate evaluation of the evolution of the microstructure and failure mechanism of the material. In combination with the urgent need for the durability of artificial joint materials under actual service conditions, it is very necessary to develop an artificial joint in-situ testing machine with a variable curvature microchannel to realize anisotropic clamps. Summary of the invention

[0006] The purpose of the present invention is to provide an artificial joint in-situ testing machine based on a variable curvature microfluidic channel fixture and a method of using the same. A variable curvature microfluidic channel combining a semicircle and an arc is arranged in a flexible gasket to achieve force anisotropy. The semicircular microfluidic channel avoids stress concentration, and the arc microfluidic channel realizes the interaction between the flow of liquid medium and the sample observation area.

[0007] To achieve the above-mentioned objectives, the present invention provides an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture, comprising a driving unit, a fixture testing unit and a moving unit on a platform base, the driving unit being located on one side of the platform base, the driving unit and the moving unit being connected by a gear transmission assembly, the moving unit being respectively connected to a fixture assembly and a test assembly of the fixture testing unit through a slider assembly, the liquid pool of the fixture testing unit being located in the center of the platform base, the fixture assembly being located inside the liquid pool, and a temperature control assembly being also provided inside the liquid pool.

[0008] Preferably, the servo motor of the driving unit is connected to the platform base through a servo motor support seat, the output shaft of the servo motor is connected to the first gear of the gear transmission assembly, the second gear of the gear transmission assembly is sleeved on the first transmission rod of the mobile unit, and the first gear is meshed with the second gear.

[0009] Preferably, worm gears are provided at both ends of the first transmission rod of the mobile unit, the worm gears are meshed with the worm wheel on the second transmission rod, and the second transmission rod is symmetrically provided with transmission thread portions with opposite thread directions, and the transmission thread portions are threadedly connected to the slider assembly, and the two ends of the first transmission rod are respectively connected to the platform base through the first support seat and the second support seat, and the angle between the first transmission rod and the second transmission rod is 90°.

[0010] Preferably, the platform base is provided with a measuring assembly on the side of the slider assembly away from the liquid pool, and a grating reading head is provided on the grating ruler of the measuring assembly. The grating ruler is connected to the platform base, and the grating reading head is connected to the first slider of the slider assembly.

[0011] Preferably, the first slider of the slider assembly is connected to one side of the force measuring piece of the test assembly. The cross-section of the force measuring piece is a U-shaped structure. Sliding grooves are symmetrically provided on both sides of the force measuring piece. The sliding grooves are slidably connected to the side walls of the liquid pool. The rear side of the force measuring piece is connected to one end of the mechanical sensor in the liquid pool, and the other end of the mechanical sensor is connected to the left clamp of the clamp assembly through a connector.

[0012] Preferably, the second slider of the slider assembly is connected to one side of the motor fixing frame, and a waterproof motor is connected to the side of the motor fixing frame away from the left clamp, and the waterproof motor passes through the motor fixing frame and is connected to the right clamp.

[0013] Preferably, the electric heating rod and the waterproof temperature measuring probe of the temperature control component are both located inside the liquid pool.

[0014] Preferably, the left clamp and the right clamp have the same structure, a clamp cover is connected to the top of the left clamp, a test slot is provided between the left clamp and the clamp cover, a flexible gasket is provided at the bottom of the test slot, a semicircular microfluidic channel and an arc microfluidic channel are provided on the flexible gasket, the semicircular microfluidic channel and the arc microfluidic channel are connected, the semicircular microfluidic channel is composed of a number of microfluidic channels with uniformly increasing radii and the same center, and the width of the arc microfluidic channel is the same as the width of the semicircular microfluidic channel.

[0015] Preferably, the number of the second transmission rods is one on each side of the left and right sides of the liquid pool, and both ends of the second transmission rod are respectively connected to the platform base through the third support seat and the fourth support seat, and the second transmission rod passes through the third support seat and is connected to the worm gear.

[0016] The method for using the above-mentioned in-situ testing machine for artificial joints based on the variable curvature microfluidic fixture comprises the following steps: S1. Start the servo motor of the driving unit to drive the second transmission rod of the moving unit to rotate, adjust the distance between the left clamp and the right clamp of the clamp assembly, and monitor the movement distance of the slider assembly by the measuring assembly; S2. Connect the two ends of the sample to be tested to the left clamp and the right clamp respectively, and tighten the clamp cover so that the sample to be tested squeezes the flexible gasket; S3, adding synovial fluid into the liquid pool, turning on the electric heating rod to heat the synovial fluid, and monitoring the temperature of the synovial fluid through a waterproof temperature control probe; S4. Start the waterproof motor to drive the fixture assembly and the test sample to rotate, and the mechanical sensor monitors the mechanical data.

[0017] Therefore, the present invention adopts the above-mentioned structure of an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture and a method of using the same, and its beneficial effects are: 1. The in-situ testing machine provided by the present invention has a compact structure, with a main body size of 240 mm × 232 mm × 80 mm, and is suitable for most scanning electron microscope sample chambers; 2. The in-situ testing machine provided by the present invention can reproduce the service environment of artificial joint samples, including constructing a liquid environment and a temperature environment, accurately simulating the environmental conditions of artificial joints in actual use, covering the compound movement and different stress conditions in the joint fluid environment, realizing in vitro mechanical testing of prosthetic materials, and avoiding the influence of environmental factors on the evaluation results of the macroscopic and micro-area mechanical properties of the test samples; 3. The flexible gasket provided by the present invention is provided with semicircular microchannels and arc microchannels that are interconnected. After being squeezed, the flexible gasket expands its contact area with the sample to be tested, thereby increasing the static friction between the contact surface of the fixture assembly and the sample to be tested, thereby avoiding unstable factors such as displacement of the sample to be tested during the test process; 4. The present invention provides a variable curvature microchannel that combines a semicircle and an arc to achieve force anisotropy. The semicircular microchannel avoids stress concentration, and the arc microchannel realizes the interaction between the flow of the liquid medium and the sample observation area. At the same time, the wall microchannel opening is a gradually expanding channel, which accelerates the flow of the liquid in the microchannel, avoids temperature concentration, and makes the temperature distribution uniform.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture of the present invention; Figure 2 It is a schematic diagram of the side view connection of the clamp assembly in the present invention; Figure 3It is a schematic structural combination diagram of the flexible gasket and the left clamp in the present invention; Figure 4 is a two-dimensional diagram of friction force-time in the test example of the present invention; Figure 5 It is a schematic diagram of the test structure connection in the test example of the present invention; Figure 6 It is a gasket-sample temperature distribution diagram in the test example of the present invention.

[0020] Reference numerals: 1. Servo motor; 2. Servo motor support seat; 3. First gear; 4. First support seat; 5. Worm gear; 6. Platform base; 7. First transmission rod; 8. Worm; 9. Second support seat; 10. Third support seat; 11. Nut; 12. Grating ruler; 13. Grating reading head; 14. Second transmission rod; 15. First movable connecting piece; 16. Fourth support seat; 17. First slider; 18. Slide rail; 19. Liquid pool; 20. Force measuring piece; 21. Mechanical sensor; 22. Connector; 23. Heating rod; 24. Left clamp; 25. Clamp cover; 26. Waterproof temperature measuring probe; 27. Test sample; 28. Right clamp; 29. ​​Motor fixing bracket; 30. Waterproof motor; 31. Computer; 32. Instruments and meters; 33. Power supply. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0022] Example 1 like Figure 1 As shown, the present invention provides an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture, including a driving unit, a fixture test unit and a moving unit on a platform base 6. The driving unit is located on one side of the platform base 6, and the driving unit and the moving unit are connected through a gear transmission assembly. The moving unit is respectively connected to the fixture assembly and the test assembly of the fixture test unit through a slider assembly, and the liquid pool 19 of the fixture test unit is located in the center of the platform base 6. The fixture assembly is located inside the liquid pool 19, and a temperature control assembly is also provided inside the liquid pool 19.

[0023] The in-situ test machine in this embodiment has a compact structure, and the main body size is 240 mm × 232 mm × 80 mm, which is suitable for most scanning electron microscope sample chambers, and is convenient for obtaining structural feature images of the sample to be tested under different load conditions. The platform base 6 is fixed by connecting with other rigid bases through threads, the driving unit drives the moving unit to move, and the moving unit drives the clamp assembly in the clamp test unit to move through the slider assembly. The clamp assembly clamps and fixes the sample to be tested 27, and the test assembly measures the mechanical data of the sample to be tested 27. The liquid pool 19 provides the actual working temperature in the body for the sample to be tested 27, and the temperature control assembly heats the synovial fluid in the liquid pool 19 and controls it to maintain the working temperature.

[0024] The in-situ test machine provides the required drive for each unit through an external power supply 33. The data of the test component, the temperature control component and the grating ruler 12 are transmitted to the matching instrument 32 through the existing technology. The computer 31 controls the parameters of the temperature control component through the existing technology. The grating ruler 12 and the grating reading head 13 are used in conjunction with the instrument 32 to collect and analyze the test data such as displacement and temperature.

[0025] The servo motor 1 of the driving unit is connected to the platform base 6 through the servo motor support seat 2, and the output shaft of the servo motor 1 is connected to the first gear 3 of the gear transmission assembly. The second gear of the gear transmission assembly is sleeved on the first transmission rod 7 of the mobile unit, and the first gear 3 is meshed with the second gear. The servo motor 1 starts to drive the first gear 3 to rotate, and the first gear 3 drives the first transmission rod 7 to rotate through the second gear. Both the first gear 3 and the second gear are bevel gears.

[0026] The first transmission rod 7 of the mobile unit is sleeved with worms 8 at both ends, and the worms 8 are meshed with the worm wheel 5 on the second transmission rod 14. The second transmission rod 14 is symmetrically provided with transmission threaded parts with opposite thread directions, and the transmission threaded parts are threadedly connected with the slider assembly. The first transmission rod 7 is connected to the platform base 6 at both ends through the first support seat 4 and the second support seat 9, respectively, and the angle between the first transmission rod 7 and the second transmission rod 14 is 90°.

[0027] The first transmission rod 7 rotates to drive the worm 8 to rotate, and the worm 8 drives the worm wheel 5 below it to rotate, thereby driving the second transmission rod 14 to rotate. The second transmission rod 14 drives the nut 11 threadedly connected to it to move through the transmission threaded portion with the opposite thread direction, and the nut 11 drives the slider assembly connected to it to move, thereby completing the adjustment of the position of the clamp assembly. The first support seat 4 and the second support seat 9 are set to ensure the smooth rotation of the first transmission rod 7 hinged thereto.

[0028] The platform base 6 is provided with a measuring assembly on the side of the slider assembly away from the liquid pool 19, and a grating reading head 13 is provided on the grating ruler 12 of the measuring assembly. The grating ruler 12 is connected to the platform base 6, and the grating reading head 13 is connected to the first slider 17. The grating reading head 13 measures the displacement data of the fixture assembly by monitoring the displacement of the slider assembly.

[0029] The first slider 17 of the slider assembly is connected to one side of the force measuring piece 20 of the test assembly, and the cross section of the force measuring piece 20 is a U-shaped structure. Sliding grooves are symmetrically arranged on both sides of the force measuring piece 20, and the sliding grooves are slidably connected to the side walls of the liquid pool 19. The rear side of the force measuring piece 20 is connected to one end of the mechanical sensor 21 in the liquid pool 19, and the other end of the mechanical sensor 21 is connected to the left clamp 24 of the clamp assembly through the connector 22.

[0030] The setting of the sliding groove on the force measuring member 20 facilitates the force measuring meter to move smoothly along the liquid pool 19 driven by the first slider 17. The first movable connecting member 15 is provided on the first slider 17, and the part of the first movable connecting member 15 protruding from the first slider 17 is connected to the side wall of the force measuring member 20. The setting of the first movable connecting member 15 ensures that the movement of the first slider 17 is not affected by the force measuring member 20.

[0031] The mechanical sensor 21 is a double-screw mechanical sensor 21, and a thread groove is provided on the rear side of the force measuring piece 20, and the thread groove is threadedly connected to the screw at one end of the mechanical sensor 21, and the screw at the other end of the mechanical sensor 21 is threadedly connected to the connector 22. While the mechanical sensor 21 tests the mechanical data of the test piece, its double-screw structure ensures that the fixture assembly can rotate under the drive of the waterproof motor 30.

[0032] The second slider of the slider assembly is connected to one side of the motor fixing frame 29 . The side of the motor fixing frame 29 away from the left clamp 24 is connected to a waterproof motor 30 . The waterproof motor 30 passes through the motor fixing frame 29 and is connected to the right clamp 28 .

[0033] The second slider is provided with a second movable connecting member, and the part of the second movable connecting member protruding from the second slider is connected to the motor fixing frame 29. The motor fixing frame 29 moves relative to the liquid pool 19 under the drive of the second slider. When the two ends of the test piece are connected to the left clamp 24 and the right clamp 28 respectively, the waterproof motor 30 is started to drive the test piece, the left clamp 24, the connector 22 and the mechanical sensor 21 to rotate together through the right clamp 28.

[0034] The electric heating rod 23 and the waterproof temperature measuring probe 26 of the temperature control component are both located inside the liquid pool 19, and the electric heating rod 23 is a submersible electric heating rod 23. When working, the temperature control component is located below the liquid surface of the synovial fluid, and the synovial fluid in the liquid pool 19 is heated by the electric heating rod 23, and the waterproof temperature measuring probe 26 monitors the temperature of the synovial fluid, so that the synovial fluid accurately reaches the service environment temperature of the test piece.

[0035] like Figure 2 and Figure 3 As shown, the left clamp 24 and the right clamp 28 have the same structure, the top of the left clamp 24 is connected to a clamp cover 25, and a test slot is provided between the left clamp 24 and the clamp cover 25. A flexible gasket is provided at the bottom of the test slot, and the flexible gasket is a variable curvature gasket. A semicircular microfluidic channel and an arc microfluidic channel are provided on the flexible gasket. The semicircular microfluidic channel is far away from the opening of the test slot, and the arc microfluidic channel is close to the opening of the test slot. The semicircular microfluidic channel is connected to the arc microfluidic channel. The semicircular microfluidic channel is composed of a number of microfluidic channels with uniformly increasing radii and the same center, and the width of the arc microfluidic channel is the same as the width of the semicircular microfluidic channel.

[0036] The test piece is fixed between the fixture cover 25 and the flexible gasket. By controlling the tightening degree of the fixture cover 25, the test piece squeezes the flexible gasket to different degrees. The flexible gasket deforms under pressure and has different contact areas with the test piece. The test sample 27 is perpendicular to the tangent of the semicircular microchannel in any direction of pressure, realizing force anisotropy, greater resistance to dislocation movement, and improving the static friction coefficient to solve the problem of stress concentration. The arc microchannel is close to the electron microscope observation area, which is conducive to the circulation of the liquid medium in the stretching direction, realizing the interaction between the liquid flow and the electron microscope observation area of ​​the sample.

[0037] The arrangement of the semicircular microchannel and the arc microchannel ensures that after the test piece contacts the flexible gasket, the vertical section of the flexible gasket presents a flow channel opening that is larger than the hole wall spacing, forming a gradually expanding channel, accelerating the flow of synovial fluid to carry away heat, and the distance from the electron microscope observation area is inversely proportional to the width of the flow channel opening, thereby avoiding the influence of temperature concentration caused by the contact between the flexible gasket and the fixture assembly on the mechanical test results.

[0038] The number of the second transmission rods 14 is one on each side of the left and right sides of the liquid pool 19. The two ends of the second transmission rod 14 are connected to the platform base 6 through the third support seat 10 and the fourth support seat 16 respectively. The second transmission rod 14 passes through the third support seat 10 and is connected to the worm gear 5. With the number of second transmission rods 14, both sides of the clamp assembly are driven by the slider assembly to ensure the smooth movement of the clamp assembly. The top of the third support seat 10 and the fourth support seat 16 are connected with a slide rail 18, and the slide rail 18 is slidably connected to the middle of the first slider 17 and the middle of the second slider.

[0039] Example 2 A method for using an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture in Example 1 comprises the following steps: S1. Start the servo motor of the driving unit to drive the second transmission rod of the moving unit to rotate, adjust the distance between the left clamp and the right clamp of the clamp assembly, and monitor the movement distance of the slider assembly by the measuring assembly.

[0040] S2. Connect the two ends of the sample to be tested to the test slot of the left fixture and the test slot of the right fixture respectively, and tighten the fixture cover so that the sample to be tested presses the flexible gasket in the test slot.

[0041] S3. Add synovial fluid into the liquid pool, turn on the electric heating rod to heat the synovial fluid, and monitor the temperature of the synovial fluid through the waterproof temperature control probe.

[0042] S4. Start the waterproof motor to drive the fixture assembly and the test sample to rotate, and the mechanical sensor monitors the mechanical data.

[0043] Test Example 1 No gasket, ordinary gasket and the flexible gasket of the present invention are respectively arranged in the left and right clamps, and the test sample is set to move left and right, and the friction simulation analysis between the test sample and the contact surface of each gasket is performed. The results are as follows: Figure 4 The flexible gasket in the present invention makes the average static friction between the sample and the fixture assembly higher than that of the ordinary gasket by 19.2% and that of no gasket by 83.9%, and the stress distribution between the contact surface of the fixture assembly and the sample to be tested is uniform, and the fixing effect is increased.

[0044] like Figure 5 As shown, a common gasket and a flexible gasket provided by the present invention are set, and the temperature distribution results of the gasket-test sample are as follows: Figure 6 As shown, in the experimental simulation, the temperature of the sample portion contacted by the ordinary gasket on the right is 10.5% higher than that of the variable curvature microchannel gasket on the left, which proves that the flexible gasket provided by the present invention can solve the temperature concentration problem due to its variable curvature texture.

[0045] Therefore, the present invention adopts the above-mentioned structure to form an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture and a method of using the same. A variable curvature microfluidic channel combining a semicircle and an arc is arranged in the flexible gasket to achieve force anisotropy. The semicircular microfluidic channel avoids stress concentration, and the arc microfluidic channel realizes the interaction between the flow of the liquid medium and the sample observation area.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An artificial joint in-situ testing machine based on a variable curvature microfluidic fixture, characterized in that: It includes a driving unit, a fixture test unit and a moving unit on a platform base. The driving unit is located on one side of the platform base. The driving unit and the moving unit are connected through a gear transmission assembly. The moving unit is respectively connected to the fixture assembly and the test assembly of the fixture test unit through a slider assembly. The liquid pool of the fixture test unit is located in the center of the platform base, the fixture assembly is located inside the liquid pool, and a temperature control assembly is also provided inside the liquid pool.

2. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 1, characterized in that: The servo motor of the driving unit is connected to the platform base through the servo motor support seat, the output shaft of the servo motor is connected to the first gear of the gear transmission assembly, the second gear of the gear transmission assembly is sleeved on the first transmission rod of the mobile unit, and the first gear is meshed with the second gear.

3. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 2, characterized in that: Worms are sleeved on both ends of the first transmission rod of the mobile unit, and the worms are meshed with the worm wheels on the second transmission rod. The second transmission rod is symmetrically provided with transmission threaded parts with opposite thread directions, and the transmission threaded parts are threadedly connected to the slider assembly. The two ends of the first transmission rod are respectively connected to the platform base through the first support seat and the second support seat, and the angle between the first transmission rod and the second transmission rod is 90°.

4. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 1, characterized in that: A measuring component is provided on the platform base at a side of the slider component away from the liquid pool, and a grating reading head is provided on the grating ruler of the measuring component.

5. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 1, characterized in that: The first slider of the slider assembly is connected to one side of the force measuring piece of the test assembly. The cross-section of the force measuring piece is a U-shaped structure. Sliding grooves are symmetrically provided on both sides of the force measuring piece. The sliding grooves are slidably connected to the side walls of the liquid pool. The rear side of the force measuring piece is connected to one end of the mechanical sensor in the liquid pool, and the other end of the mechanical sensor is connected to the left clamp of the clamp assembly through a connector.

6. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 5, characterized in that: The second slider of the slider assembly is connected to one side of the motor fixing frame, and a waterproof motor is connected to the side of the motor fixing frame away from the left clamp. The waterproof motor penetrates the motor fixing frame and is connected to the right clamp.

7. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 1, characterized in that: The electric heating rod and the waterproof temperature measuring probe of the temperature control component are both located inside the liquid pool.

8. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 6, characterized in that: The left fixture and the right fixture have the same structure. The top of the left fixture is connected to a fixture cover. A test slot is provided between the left fixture and the fixture cover. A flexible gasket is provided at the bottom of the test slot. A semicircular microfluidic channel and an arc microfluidic channel are provided on the flexible gasket. The semicircular microfluidic channel and the arc microfluidic channel are connected. The semicircular microfluidic channel is composed of a number of microfluidic channels with uniformly increasing radii and the same center. The width of the arc microfluidic channel is the same as that of the semicircular microfluidic channel.

9. The artificial joint in-situ testing machine based on the variable curvature microfluidic fixture according to claim 3, characterized in that: The number of the second transmission rods is one on each side of the left and right sides of the liquid pool. Both ends of the second transmission rod are connected to the platform base through the third support seat and the fourth support seat respectively. The second transmission rod passes through the third support seat and is connected to the worm gear.

10. A method for using an artificial joint in-situ testing machine based on a variable curvature microfluidic fixture according to any one of claims 1 to 9, characterized in that: The following steps are included: S1. Start the servo motor of the driving unit to drive the second transmission rod of the moving unit to rotate, adjust the distance between the left clamp and the right clamp of the clamp assembly, and monitor the movement distance of the slider assembly by the measuring assembly; S2. Connect the two ends of the sample to be tested to the left clamp and the right clamp respectively, and tighten the clamp cover so that the sample to be tested squeezes the flexible gasket; S3, adding synovial fluid into the liquid pool, turning on the electric heating rod to heat the synovial fluid, and monitoring the temperature of the synovial fluid through a waterproof temperature control probe; S4. Start the waterproof motor to drive the fixture assembly and the test sample to rotate, and the mechanical sensor monitors the mechanical data.

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