An in-situ mechanical testing device

Abstract

The utility model discloses a kind of in-situ mechanics experimental devices, it is related to material mechanics performance test technical field.The device adopts macro and micro hierarchical driving architecture.Macro coarse adjustment module contains lead screw, guide rail, transmission seat and bearing seat, bearing seat includes boss, recess structure, lead screw is arranged along recess axial and both ends fixed support, workbench is matched with guide rail by double slide block, slider sets support piece and realizes surface contact bearing.Micro fine adjustment module contains multiple beam arm type right angle flexible structure of symmetrical arrangement, connecting longitudinal arm and connecting crossbeam are perpendicular and reserved gap, constrain nanometer level accurate displacement of mobile.Both ends of base are provided with baffle, so that each component is linear coaxial arrangement, indenter is conical head and end with circular arc surface.The utility model considers wide range fast coarse positioning and nanometer level fine adjustment loading, load transmission is uniform, stable in operation, adapts compact test space, can avoid sample damage, widen application range, improve test efficiency and data reliability.

Description

Technical Field

[0001] This utility model relates to the field of material mechanical property testing technology, and in particular to an in-situ mechanical experimental device. Background Technology

[0002] In materials science research and industrial testing, some in-situ mechanical experimental devices employ only a single drive mode. They either rely on macro-motion mechanisms to achieve large-scale movement but lack sufficient displacement accuracy, or rely solely on micro-motion mechanisms to ensure accuracy but have extremely low positioning efficiency, making it difficult to balance testing efficiency and data accuracy. Other devices, while attempting to adopt a hierarchical drive architecture combining macro-motion and micro-motion, suffer from unreasonable structural design issues. For example, the lead screw and table transmission of the macro-motion module have a large clearance and lack a stable guiding constraint structure, causing the table to wobble easily during coarse positioning, affecting subsequent fine-tuning benchmarks. The elastic beam structure of the micro-motion module is mostly a single beam or asymmetrical layout, which easily generates cross-coupling errors during the movement of the mover, making it difficult to achieve nanometer-level precise displacement output.

[0003] Therefore, how to design an in-situ mechanical experimental device that can effectively ensure high displacement accuracy, improve experimental efficiency, and adapt to the actual application needs of in-situ mechanical testing has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0004] The purpose of this invention is to provide an in-situ mechanical experimental device to solve the problems existing in the prior art, effectively ensure high displacement accuracy, improve experimental efficiency, and meet the practical application needs of in-situ mechanical testing.

[0005] To achieve the above objectives, this utility model provides the following solution: an in-situ mechanical experimental apparatus, comprising: A macro-motion coarse adjustment module, comprising a worktable, a macro-motion drive component, and a lead screw, wherein the output end of the macro-motion drive component is connected to the lead screw drive, and the worktable is engaged with the lead screw drive. A micro-motion fine-tuning module is disposed on the worktable. The micro-motion fine-tuning module includes a micro-motion base, a micro-drive component, a flexible hinge, and a mover. The micro-motion base has a mounting groove, the main body of the micro-drive component is embedded in the mounting groove, and the driving end of the micro-drive component protrudes from the micro-motion base. The flexible hinge includes a first elastic beam structure and a second elastic beam structure symmetrically connected to both sides of the mover. The fixed ends of the first elastic beam structure and the second elastic beam structure are both fixedly connected to the side wall of the micro-motion base. The driving end of the micro-drive component is connected to the mover. A pressure head assembly, comprising a pressure head seat and a pressure head, wherein the driving end of the micro-drive unit is connected to the pressure head seat via the mover, and the top of the pressure head seat is rigidly connected to the pressure head; And a sample fixing device for fixing the test sample, wherein the sample fixing area of ​​the sample fixing device is arranged opposite to the indenter.

[0006] As one embodiment, both the first elastic beam structure and the second elastic beam structure include a right-angled flexible structure, which includes at least two connecting crossbeams; and adjacent connecting crossbeams are connected by connecting longitudinal arms, the axis of which is perpendicular to the axis of the connecting crossbeam.

[0007] In one embodiment, the connecting beam at the outer end is fixedly connected to the side wall of the micro-motion seat via a connecting seat, and the connecting beam at the inner end is fixedly connected to the side wall of the mover as a movable end. A preset gap is reserved between the connecting longitudinal arm and the connecting beam and the micro-motion seat.

[0008] As one embodiment, the macro-motion coarse adjustment module further includes a guide rail and a transmission seat; the guide rail is mounted on the base, and the axis of the guide rail is parallel to the axis of the lead screw; the transmission seat is sleeved on the outside of the lead screw and threadedly engages with the lead screw to form a threaded pair, and the transmission seat is fixedly connected to the worktable; the lower surface of the worktable slides with the guide rail through a slider.

[0009] In one embodiment, the base is provided with a support seat, which includes two symmetrically arranged bosses and a groove between the two bosses; the top surface of each boss is equipped with a guide rail; the axis of the groove along its length is parallel to the axis of the guide rail, and the lead screw is arranged along the axial direction of the groove.

[0010] As one embodiment, the end of the lead screw away from the macro drive component is provided with a support seat, the support seat is disposed in the groove, and the bottom of the support seat is fixedly connected to the bottom surface of the groove; a bearing is provided on the support seat, and the inner ring of the bearing is connected to the shaft end of the lead screw.

[0011] As one embodiment, two sliders are spaced apart on the guide rail on the top surface of each boss.

[0012] In one embodiment, a support member is fixedly provided on the outer wall of the slider; the top surface of the support member is in contact with the bottom surface of the worktable to form a surface contact support; the worktable and the slider are fixedly connected by bolts.

[0013] In one embodiment, the base is provided with a first baffle and a second baffle at its two ends along its length, and both the first baffle and the second baffle are spaced apart from the support seat; the sample fixing device is fixed on the side of the first baffle facing the support seat; the macro-drive component is disposed between the second baffle and the support seat.

[0014] As one embodiment, the pressure head includes a conical head, the end of which has an arcuate surface.

[0015] The present invention achieves the following technical advantages over the prior art: 1. This utility model adopts a hierarchical drive architecture of macro-motion coarse adjustment and micro-motion fine adjustment. The macro-motion module achieves large-range and rapid coarse positioning through the transmission cooperation between the lead screw and the worktable. The micro-motion module relies on the symmetrical arrangement of the first and second elastic beam structures to constrain the movement of the mover. With the design that the axis of the pressure head is collinear with the driving direction of the micro-drive component, it effectively ensures the nanometer-level displacement output accuracy and high work efficiency. At the same time, the sample fixing device can stably clamp the sample to be tested, avoiding positional displacement during the experiment. The symmetrical layout of the flexible hinge and the rigid connection method further improve the uniformity of load transfer, laying a foundation for the accuracy of in-situ mechanical testing from a structural perspective.

[0016] The experimental procedure follows an orderly logic of "sample fixing - macro-motion coarse positioning - micro-motion fine adjustment testing - reset sampling". The graded operation of coarse and fine adjustment not only quickly reduces the test interval and improves experimental efficiency through the macro-motion module, but also achieves precise loading with the help of the micro-motion module, taking into account both test speed and data reliability. With the rigid connection and limit design of each module, the device's service life is extended while ensuring operational safety. The overall process is simple and easy to operate, and is suitable for the actual application needs of in-situ mechanical testing.

[0017] Other technical solutions of this utility model have also achieved the following technical effects: 2. In the micro-motion fine-tuning module structure, the multi-beam arm right-angle flexible structure, through a combination of at least two parallel connecting crossbeams and vertical connecting longitudinal arms, along with the vertical design of the connecting longitudinal arms and connecting crossbeams and the integrated molding process, makes elastic deformation more controllable, effectively reducing displacement cross-coupling errors. Combined with the "beam-arm-beam" series layout, load transfer is more uniform, further improving the micro-motion displacement resolution to below the nanometer level. The pre-set gaps between the connecting longitudinal arms, connecting crossbeams, and micro-motion seats not only avoid mechanical interference during deformation but also reduce frictional losses, extending the fatigue life of the flexible structure. Simultaneously, it ensures the smooth movement of the mover in high-frequency tests, making nanometer-level loading more stable and reliable.

[0018] 3. Optimized design of the guide rails, bearing seats, support seats, and slider structures of the macro-motion module has resulted in a high-rigidity, high-precision coarse adjustment transmission system. The "boss and groove" layout of the bearing seats allows the guide rails to be symmetrically distributed on both sides of the lead screw, achieving concealed installation of the lead screw, simplifying the structural layout, and improving the straightness of the worktable movement through symmetrical support. The support seat design fixed at both ends of the lead screw, combined with bearing constraints, significantly reduces axial and radial runout during lead screw rotation, improving the stability of the screw drive. The double sliders spaced apart on each guide rail, along with the support components on the outer wall of the sliders, distribute the worktable load through surface contact support, reducing worktable deflection deformation. Combined with rigid bolt fixing, this further enhances the torsional stiffness and load-bearing capacity of the macro-motion module, ensuring micron-level positioning accuracy during large-range coarse positioning, balancing coarse adjustment efficiency and reference accuracy.

[0019] 4. The first and second baffles at both ends of the base not only provide a precise installation reference for the sample fixing device and the macro drive component, making the components linearly coaxially arranged, reducing the overall axial dimension of the device, and adapting to compact spaces such as SEM sample chambers, but also avoid motion interference through the gap avoidance design. At the same time, the second baffle provides lateral protection for the macro drive component, blocking dust and collision interference, and improving the operational safety of the device. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the structure of the present invention, omitting the micro-adjustment module; Figure 4 This is a schematic diagram of the structure of the present invention, omitting the micro-adjustment module and the worktable; Figure 5 This is a schematic diagram of the micro-adjustment module structure of this utility model; Figure 6 This is a schematic diagram of the lead screw structure of this utility model; Figure 7 Schematic diagrams of three types of flexible hinge pairs; Figure 8 This is a schematic diagram of the FEA calculation results for a right-angle flexible hinge; Figure 9 This is a schematic diagram of the FEA calculation results for a straight circular flexible hinge; Figure 10 This is a schematic diagram of the FEA calculation results for a V-shaped flexible hinge.

[0022] The components are as follows: 1. Worktable; 2. Macro drive component; 3. Lead screw; 4. Sample fixing device; 5. Micro-motion seat; 6. Micro drive component; 7. Mover; 8. Mounting groove; 9. First elastic beam structure; 10. Second elastic beam structure; 11. Indenter seat; 12. Indenter; 1201. Conical head; 13. Connecting longitudinal arm; 14. Connecting crossbeam; 15. Connecting seat; 16. Guide rail; 17. Transmission seat; 18. Slider; 1801. Support component; 19. Boss; 20. Groove; 21. Support seat; 22. First baffle; 23. Second baffle. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] This embodiment provides an in-situ mechanical experimental setup. Please refer to [reference needed]. Figure 1-6As shown, the system includes a macro coarse adjustment module, a micro fine adjustment module, an indenter assembly, and a sample fixing device 4. The macro coarse adjustment module is located on the top surface of the base and includes a worktable 1, a macro drive component 2, and a lead screw 3. The output end of the macro drive component 2 is connected to one end of the lead screw 3 via a coupling, enabling the macro drive component 2 to drive the lead screw 3 to rotate. The worktable 1 and the lead screw 3 are in a transmission cooperation, so when the macro drive component 2 drives the lead screw 3 to rotate, the lead screw 3 drives the worktable 1 to move back and forth along the axis of the lead screw 3. The micro fine adjustment module is located on the worktable 1 and includes a micro adjustment seat 5, a micro drive component 6, a flexible hinge, and a mover 7. The micro adjustment seat 5 has a mounting bracket in the middle. The mounting groove 8 is in which the main body of the micro-drive component 6 is embedded, and the driving end of the micro-drive component 6 protrudes from the micro-movement seat 5; the flexible hinge includes a first elastic beam structure 9 and a second elastic beam structure 10 symmetrically arranged on both sides of the mover 7. The fixed ends of the first elastic beam structure 9 and the second elastic beam structure 10 are fixedly connected to the side wall of the micro-movement seat 5, and the movable ends of the first elastic beam structure 9 and the second elastic beam structure 10 are connected to the mover 7; the driving end of the micro-drive component 6 is connected to the mover 7; the pressure head assembly includes a pressure head seat 11 and a pressure head 12. The driving end of the micro-drive component 6 is connected to the pressure head seat 11 through the mover 7, that is, the bottom of the pressure head seat 11 is rigidly connected to the end of the mover 7 away from the micro-drive component 6. The top of the pressure head seat 11 is rigidly connected to the pressure head 12, and the axis of the pressure head 12 is collinear with the driving direction of the micro-drive component 6; the sample fixing device 4 is located on the top surface of the base, and the sample fixing area of ​​the sample fixing device 4 is set opposite to the pressure head 12. The sample to be tested is stably clamped by the sample fixing device 4 to ensure that the sample position does not shift during the experiment.

[0026] Work methods: S1. Sample fixing step: Place the sample to be tested in the sample fixing area of ​​the sample fixing device 4. The sample is fixed stably by the clamping structure of the device to ensure that the sample position does not shift during the experiment and that the test area of ​​the sample is initially aligned with the working end of the pressure head 12.

[0027] S2. Macro-motion coarse positioning steps: Start the macro-motion drive unit 2, and its output end drives the lead screw 3 to rotate around its own axis through the coupling; since the worktable 1 and the lead screw 3 are in transmission cooperation, and as the lead screw 3 rotates, the worktable 1 moves back and forth along the axis of the lead screw 3, thereby driving the micro-motion fine adjustment module and the pressure head assembly on the worktable 1 to move synchronously until the distance between the pressure head 12 and the sample test area is reduced to the micrometer level. After the coarse positioning is completed, the macro-motion drive unit 2 is turned off.

[0028] S3. Fine-tuning and testing steps: Start the micro-drive unit 6, whose drive end pushes the mover 7 to move along the set direction, the drive direction is collinear with the axis of the indenter 12; the mover 7 produces precise micro-deformation under the constraint of the first elastic beam structure 9 and the second elastic beam structure 10 on both sides, driving the indenter seat 11 and the indenter 12 to perform nanoscale displacement synchronously, so that the indenter 12 makes precise contact with the test area of ​​the sample and applies the set load; according to the experimental requirements, maintain the pressure or displacement state of the indenter 12 to complete the in-situ mechanical test of the sample.

[0029] S4. Reset and Sampling Steps: After the test is completed, first control the micro-drive 6 to reverse the action, causing the pressure head 12 to detach from the sample surface and return to the initial position of the micro-motion; then start the macro-drive 2 to reverse the drive screw 3, causing the worktable 1 to drive the entire upper structure back to the initial position; finally, release the clamping structure of the sample fixing device 4, take out the tested sample, and complete one experimental cycle.

[0030] In one embodiment, both the first elastic beam structure 9 and the second elastic beam structure 10 include right-angled flexible structures. Each right-angled flexible structure includes a connecting longitudinal arm 13 and at least two connecting crossbeams 14. Both the connecting longitudinal arm 13 and the connecting crossbeams 14 are flexible structures with elastic deformation capabilities. The connecting longitudinal arm 13 is a strip-shaped flexible arm, and the connecting crossbeams 14 are strip-shaped flexible beams. Adjacent connecting crossbeams 14 are distributed parallel and spaced apart, and are connected by the connecting longitudinal arm 13. The axis of the connecting longitudinal arm 13 is perpendicular to the axis of the connecting crossbeams 14, and the connecting longitudinal arm 13 and the connecting crossbeams 14 can be integrally formed. When the micro-actuator 6 outputs driving force, the connecting longitudinal arm 13 and the connecting crossbeams 14 undergo bending deformation. The connecting longitudinal arm 13 coordinates the displacement synchronization of adjacent connecting crossbeams 14 through its own elastic deformation. The outermost connecting crossbeam 14 is fixedly connected to the side wall of the micro-movement seat 5 through a connecting seat 15, and the innermost connecting crossbeam 14, as the movable end, is directly fixedly connected to the side wall of the mover 7. The two ends of the connecting longitudinal arm 13 in the middle are rigidly fixed to the adjacent connecting crossbeam 14, forming a series right-angle layout of "beam-arm-beam" to ensure the uniform transmission of force and displacement.

[0031] In this embodiment, a preset gap is reserved between the connecting longitudinal arm 13 and connecting crossbeam 14 of the first elastic beam structure 9 and the second elastic beam structure 10 and the micro-motion seat 5. By reserving this gap, sufficient space is provided for the elastic deformation of the connecting crossbeam 14 and connecting longitudinal arm 13 under the driving force of the micro-drive component 6, ensuring that they can achieve precise displacement through their own micro-bending, while avoiding mechanical interference with the micro-motion seat 5 and ensuring smooth movement. In addition, the axis of the connecting crossbeam 14 is strictly parallel to the mounting reference surface of the micro-motion seat 5, which refers to the end face of the micro-motion seat 5 and the connecting seat 15. This parallel layout allows the connecting crossbeam 14 to generate linear elastic deformation in a direction parallel to the surface of the micro-motion seat 5 when driven, thereby driving the mover 7 and the pressure head assembly to output nanometer-level precise displacement in a set direction, effectively constraining the motion freedom of the mover 7, and improving the displacement direction accuracy and load transfer efficiency of micro-motion fine adjustment.

[0032] In one embodiment, the macro coarse adjustment module further includes a guide rail 16 and a transmission seat 17. The guide rail 16 is a linear guide rail, mounted on a base, and its axis is parallel to the axis of the lead screw 3. The transmission seat 17 is sleeved on the outside of the lead screw 3, and the transmission seat 17 is threadedly engaged with the lead screw 3. Preferably, the bottom of the transmission seat 17 is machined with a thread matching the lead screw 3, and the transmission seat 17 is sleeved on the outside of the lead screw 3 to form a threaded pair. The transmission seat 17 is slidably connected to the guide rail 16 via the worktable 1, and the upper surface of the transmission seat 17 is rigidly connected to the worktable 1 via bolts, so that the worktable 1 can move synchronously with the transmission seat 17. The micro fine adjustment module is mounted on the worktable 1, and the lower surface of the worktable 1 is slidably engaged with the guide rail 16 via a slider 18. The transmission seat 17 can rotate with the lead screw 3 and move stably along the axis of the guide rail 16, driving the worktable 1 and the micro fine adjustment module above it to synchronously achieve coarse adjustment displacement. During operation, the macro-drive component 2 drives the lead screw 3 to rotate. Through the threaded pair between the lead screw 3 and the transmission seat 17, the rotational motion is converted into the linear motion of the transmission seat 17. Since the transmission seat 17 is rigidly connected to the worktable 1, and the worktable 1 is constrained and guided along the guide rail 16 by the slider 18, the transmission seat 17 can move smoothly along the axis of the guide rail 16, thereby driving the worktable 1 and the micro-adjustment module above it to synchronously achieve micron-level coarse adjustment displacement.

[0033] In one embodiment, a support seat is provided on the base. The support seat has a U-shaped cross-section and specifically includes two symmetrical bosses 19 and a central groove 20. One boss 19 is provided on each side, and a guide rail 16 is mounted on the top surface of each boss 19. The groove 20 is located between the two bosses 19, forming a recessed receiving space. The axis of the groove 20 in the length direction is parallel to the axis of the guide rail 16. The lead screw 3 is arranged along the axial direction of the groove 20, concealing the lead screw 3 within the groove 20, making the guide rail layout simpler and ensuring the linear movement accuracy of the worktable 1.

[0034] In this embodiment, the end of the lead screw 3 furthest from the macro-drive component 2 is positioned and supported by a support base 21. The support base 21 is set in the groove 20, and its bottom is fixedly connected to the bottom surface of the groove 20 to ensure the installation stability of the support base 21. A bearing mounting hole is provided on the upper part of the support base 21, into which a bearing is embedded. The outer ring of the bearing mates with the mounting hole, and the inner ring is connected to the shaft end of the lead screw 3. The side of the lead screw 3 furthest from the drive end is stably constrained by the support base 21, forming a "fixed at both ends" support mode in conjunction with the motor output shaft support structure of the macro-drive component 2. Simultaneously, the height of the support base 21 matches the depth of the groove 20, allowing the support base 21 to be completely located within the groove 20. The top surface of the support base 21 is lower than the movement trajectory of the worktable 1, preventing movement interference between the support base 21 and the worktable 1, further ensuring the operational safety of the macro-coarse adjustment module.

[0035] In this embodiment, two sliders 18 are spaced apart on the guide rail 16 on the top surface of each boss 19. A support member 1801 is fixedly installed on the outer wall of the slider 18. The top surface of the support member 1801 is in contact with the bottom surface of the worktable 1, forming a surface contact support, which effectively increases the contact area to distribute the load on the worktable 1. The worktable 1 and the sliders 18 are fixed by bolts. The bolts pass through the through hole on the bottom surface of the worktable 1 and the positioning hole of the support member 1801 in sequence, and then are rigidly connected to the threaded hole inside the slider 18. This structure, which uses the surface contact support of the support member 1801 and multiple bolts for uniform fixing, enables the worktable 1 to be subjected to more balanced forces during movement, reduces deflection deformation caused by single-point support, and provides structural support for the displacement accuracy of macro-motion coarse adjustment.

[0036] In one embodiment, a first baffle 22 and a second baffle 23 are fixedly installed at both ends of the base along its length. These baffles are arranged parallel to each other and perpendicular to the top surface of the base, forming a "two-end limiting" structure along the length of the base. Both the first baffle 22 and the second baffle 23 are spaced apart from the support. The sample fixing device 4 is fixed to the side of the first baffle 22 facing the support. The macro-drive component 2 is positioned between the second baffle 23 and the support. The output shaft axis of the macro-drive component 2 is coaxial with the axis of the lead screw 3. This gap design not only provides space for the installation of the macro-drive component 2 but also provides lateral protection for the macro-drive component 2 through the second baffle 23. Through the structural design of "two-end baffles and gap avoidance," the sample fixing device 4, the support, the lead screw 3, and the macro-drive component 2 are arranged linearly on the base.

[0037] In one embodiment, the design of the micro-transmission mechanism, with the indenter 12 serving as the core actuator, directly determines the accuracy and reliability of SEM in-situ mechanical testing (indentation, scratch) through the selection of its material and geometry. ① Material selection In nano-indentation / scratch testing, the material of indenter 12 needs to meet the requirements of "high hardness and high elastic modulus". Then, depending on the usage environment, the commonly used indenter materials can be divided into two categories: at room temperature, diamond indenters are usually used; since diamond will turn into stone desert at high temperature, sapphire or boron carbide are usually used in high temperature environments.

[0038] ② Selection of pressure head Depending on the geometry of the tip, common types of nanoindenters include the Bodeich indenter, the round-headed conical indenter, and the filament indenter.

[0039] The Glass indenter is suitable for bulk materials or thin films thicker than 100 nm. It allows materials to undergo easy plastic deformation, and is therefore primarily used to characterize the hardness (Marsh hardness and indentation hardness) and modulus (indentation modulus) of materials. This indenter is also a common indenter used in instrumented indentation testing as required by testing standards. Compared to the Glass indenter, the cubic indenter has a sharper tip, making it more suitable for ultra-thin samples where plastic deformation must be limited to a small volume. Conical and spherical tips are widely used for indentation of soft polymers and MEMS structures. These indenters are also commonly used for scratch testing and friction / wear testing.

[0040] In summary, this design selects a round-headed conical diamond indenter. That is, the indenter 12 includes a conical head 1201, the end of which has a rounded surface, which can avoid the tip directly crushing the sample. At the same time, the load is transferred through the contact between the rounded surface and the sample, making it suitable for in-situ mechanical experimental scenarios such as micro-indentation and elastic modulus testing.

[0041] In one embodiment, regarding the integration scheme, this utility model adopts a two-stage drive scheme of macro-motion and micro-motion: ① Macro-motion coarse adjustment module: stepper motor, ball screw, linear guide rail. This module can achieve rapid positioning with a large stroke of ≥50mm, quickly bringing the pressure head 12 and the sample on the sample fixing device 4 close to the micron-level distance, greatly shortening the test preparation time.

[0042] ② Micro-motion fine-tuning module: piezoelectric stack drive and flexible hinge amplification mechanism, directly outputting nanometer-level precision displacement. After the macro-motion coarse adjustment is in place, the precise expansion and contraction of the piezoelectric stack and the coordinated deformation of the flexible hinge drive the indenter 12 to complete the Z-axis nanometer-level loading, meeting the high-precision force-displacement control requirements of indentation and scratch testing.

[0043] Integrated observation module: Adapted to the SEM sample chamber, it monitors the test area in real time through optical / electron imaging. The module relies on the SEM's own electron imaging system to perform real-time imaging of the test area through electron beam scanning of the SEM, and simultaneously records the contact state between the indenter 12 and the sample, microscopic deformation, and surface morphology changes.

[0044] In one embodiment, the macro-motion coarse adjustment mechanism uses a stepper motor as the macro-motion drive component 2; ① Stepper motor selection Model: PKP543N18A, Step angle: 0.72°, Maximum torque: 0.22N・m.

[0045] Driving method: Microstepping circuit achieves 5000 pulses / revolution, resolution ≤0.2μm.

[0046] Table 1. Basic Performance Table of PKP543N18A

[0047] By checking the speed-torque characteristic diagram of PKP543N18A, it can be seen that the operating speed and the operating range indicated by the necessary torque in this design are within the curve, therefore this model of motor can be used. Furthermore, the inertia ratio is 2.708103, which is much less than 30, further demonstrating that selecting this model of motor is safe and reliable.

[0048] ② Ball screw shaft design and selection Specifications: THK MDK-6mm, lead 1mm, support method: fixed support at both ends; preload 0.1kN.

[0049] Verification calculation: Axial stiffness: ≥30N / μm (meets positioning accuracy requirements). Effectively ensures the alignment stability between the indenter 12 and the sample.

[0050] Service life: >30,000 hours (based on equivalent load Lh=1.837×10⁻⁶) 7 km).

[0051] A schematic diagram of a two-section fixed-type ball screw is shown below. Figure 6 As shown.

[0052] In one embodiment, the micro-actuator 6 in the micro-adjustment mechanism is a piezoelectric stack: ① Piezoelectric stack drive The core drive unit of the micro-motion fine-tuning mechanism adopts a NanoMotions PZ150 / 5×2 / 20 piezoelectric stack, with a displacement range of 20-28μm and a resolution ≤1nm. Preload: A preload of 15MPa is applied to the thread to eliminate hysteresis.

[0053] Table 2. Basic performance of PZ 150 / 5×2 / 20 piezoelectric stack

[0054] ② Flexible Hinge Amplification Mechanism: The design of the flexible hinge includes the analysis and design of the flexible hinge pair, the amplification mechanism, and the guiding mechanism. Before designing these three main structural parts, materials are selected based on the working environment required by this design.

[0055] Material selection: Table 3 Common Flexible Hinge Materials

[0056] σ in the table s E represents the strength of the material; E represents the elastic modulus of the material.

[0057] The maximum deformation of a flexible hinge is not only related to the structural dimensions, but also closely related to the material parameters. When σ s When / E is at its maximum, the hinge has the greatest reliable deformation capacity. This ratio directly reflects the material's reliable deformation potential during the elastic deformation stage.

[0058] Therefore, according to Table 3, aluminum 075 and steel 4140 have relatively high ratios of strength to elastic modulus, indicating that they have greater reliable deformation potential in the elastic deformation stage and are more suitable for the micro-deformation transmission requirements of flexible hinges. Since the nano-indentation / scratch tester in this design is integrated into the SEM, the materials required for the flexible hinges need to be non-magnetic, and aluminum has very low magnetic permeability and is therefore a non-magnetic material.

[0059] In summary, aluminum 7075 was chosen as the material for the flexible hinge because it possesses excellent mechanical deformation potential and can meet the non-magnetic environment requirements of SEM.

[0060] In this embodiment, the selection of the flexible hinge type is as follows: This embodiment is based on the core requirements of micro-drive mechanisms for in-situ SEM testing (balancing large deformation, stress safety, and structural compactness), and uses finite element analysis to select the optimal flexible hinge type. According to flexible hinge design theory, common flexible hinge types can be divided into right-angle, straight-circular, and V-type. To verify the adaptability of different types, the commercial finite element software ABAQUS was used to model, calculate, and analyze three typical flexible hinges, and the micro-drive mechanism most suitable for integration into an in-situ testing unit within an SEM was selected.

[0061] According to the knowledge of elasticity mechanics and related literature, when designing flexible hinges and analyzing the stress inside them, the model can usually be simplified to a rigid physical model with one end fixed and the other end free. Accordingly, in the subsequent finite element calculation of the flexible hinge pair, the boundary conditions are all set to the form of one end being completely fixed and the other end being free.

[0062] Table 4 Dimensions of Three Types of Flexible Hinge Pairs

[0063] Where L, w, b, and t are references Figure 7 As shown.

[0064] In Figure 7 In the diagram, (a) is a straight circle; (b) is a right angle; and (c) is a V-shape.

[0065] Based on this, the calculation of three types of flexible hinges is performed in ABAQUS, and the modeling process is as follows: A. Material Setup Table 5. Parameter settings for flexible hinge pair materials

[0066] B. Boundary conditions: The left end of the flexible hinge is fully fixed; a load of 10N is applied to the vertical surface of the rigid arm at the right end; C. Seed density: Seed size is 0.1 mm; D. Calculation results a) Right-angle type: As shown in Table 6, the maximum stress is 134 MPa; the maximum displacement is 63.38 μm; Please refer to the schematic diagram of the FEA calculation results for the right-angle flexible hinge. Figure 8 As shown.

[0067] b) Straight-circular type: As shown in Table 6, the maximum stress is 87.36 MPa; the maximum displacement is 23.15 μm; Please refer to the schematic diagram of the FEA calculation results for the straight circular flexible hinge. Figure 9 As shown.

[0068] c) V-type: As shown in Table 6, the maximum stress is 64.79 MPa; the maximum displacement is 11.37 μm; Please refer to the schematic diagram of the FEA calculation results for the V-shaped flexible hinge. Figure 10 As shown.

[0069] E. Results Analysis Table 6 Comparison of FEA calculation results for three types of flexible hinge pairs

[0070] The maximum displacement of the right-angle flexible hinge (63.38 μm) is significantly higher than that of the circular (23.15 μm) and V-type (11.37 μm), exhibiting optimal flexibility. It can output greater deformation under the same driving load, matching the drive stroke of the piezoelectric stack and ensuring that the Z-axis fine-tuning range of the indenter 12 covers the testing requirements. The right-angle hinge has a compact structure and simple manufacturing process. Its vertical array layout (connecting the longitudinal arm 13 perpendicular to the connecting beam 14) reduces space occupation, adapting to the confined environment of the SEM sample chamber, and facilitating integration with the micro-motion seat 5 and the indenter seat 11. The maximum stress of all three flexible hinges is less than the allowable stress of Al7075 (503 MPa), while the right-angle flexible hinge has the largest maximum displacement, indicating the greatest flexibility. It can achieve the maximum displacement output value while ensuring safety and reliability. Therefore, this design selects the right-angle flexible hinge pair.

[0071] Working method of in-situ mechanical experimental apparatus: S1. Sample Fixing and Initial Alignment Steps: Place the sample to be tested in the fixing area of ​​the sample fixing device 4 on the side of the first baffle 22 facing the bearing seat. The sample is stably fixed by the clamping structure of the device to ensure that the sample position does not shift during the experiment. Adjust the sample placement posture to initially align the test area of ​​the sample with the working end of the indenter 12, and ensure that the axis of the sample fixing area is coaxial with the axis of the indenter 12, laying the foundation for accurate contact in subsequent tests.

[0072] S2. Macro-motion coarse positioning step: Activate the macro-motion drive unit 2 located between the second baffle 23 and the bearing seat. Its output shaft is coaxially driven with the lead screw 3, driving the lead screw 3 to rotate around its own axis. Since the lead screw 3 is axially arranged along the groove 20 of the bearing seat, and forms a "fixed at both ends" support mode through the support seat 21 and the support structure at the end of the macro-motion drive unit 2, the axial and radial runout during rotation is strictly constrained. The lead screw 3 and the transmission seat 17 sleeved on its outer side form a threaded pair, and the rotational motion is converted into the linear motion of the transmission seat 17. The transmission seat 17 is rigidly connected to the worktable 1, and the worktable 1 slides with the guide rail 16 on the top surface of the bearing seat boss 19 through the bottom slider 18. The support member 1801 on the outer wall of the slider 18 forms a surface contact support with the bottom surface of the worktable 1, distributing the load and ensuring force balance. Under the guidance and constraint of the guide rail 16, the transmission seat 17 drives the worktable 1 and the micro-adjustment module above it to move smoothly along the axis of the guide rail 16 until the distance between the pressure head 12 and the sample testing area is reduced to the micrometer level. After the coarse positioning is completed, the macro drive 2 is turned off.

[0073] S3. Fine-tuning and in-situ testing steps: Activate the micro-drive unit 6 embedded in the mounting slot 8 of the micro-motion seat 5. Its drive end pushes the mover 7 to move along the set direction, and the drive direction is collinear with the axis of the pressure head 12. The first elastic beam structure 9 and the second elastic beam structure 10 on both sides of the mover 7 are "beam-arm-beam" series right-angle flexible structures. Adjacent connecting crossbeams 14 are distributed in parallel at intervals and are vertically connected by connecting longitudinal arms 13 and integrally formed. The outermost connecting crossbeam 14 is fixed to the micro-motion seat 5 via the connecting seat 15, and the innermost connecting crossbeam 14 is fixed to the mover 7. Because a preset gap is reserved between the connecting longitudinal arm 13, the connecting crossbeam 14, and the micro-motion seat 5, and the axis of the connecting crossbeam 14 is strictly parallel to the mounting reference surface (end face of the connecting seat 15) of the micro-motion seat 5, when the micro-drive component 6 outputs driving force, the connecting longitudinal arm 13 and the connecting crossbeam 14 undergo controllable bending deformation. The connecting longitudinal arm 13 coordinates the displacement synchronization of the adjacent connecting crossbeam 14 through its own elastic deformation, avoiding the movement of the mover 7. Under the constraint of the elastic beam structure, the mover 7 generates nanometer-level precise displacement, driving the pressure head seat 11 and pressure head 12, which are rigidly connected to it, to move synchronously, so that the pressure head 12 makes precise contact with the test area of ​​the sample and applies the set load. According to the experimental requirements, the pressure or displacement state of the pressure head 12 is maintained to complete the in-situ mechanical test of the sample.

[0074] S4. Reset and Sampling Procedure: After the test, first control the micro-drive 6 to reverse its movement, causing the pressure head 12 to detach from the sample surface. The elastic beam structure returns to its initial shape, and the mover 7 returns to its initial micro-motion position. Then, start the macro-drive 2 to reverse the drive screw 3, causing the transmission seat 17 to drive the worktable 1 and the upper structure back to their initial position along the guide rail 16. The support seat 21 is completely located within the groove 20, and its top surface is lower than the movement trajectory of the worktable 1, thus avoiding motion interference. Finally, release the clamping structure of the sample fixing device 4, remove the tested sample, and complete one experimental cycle. Throughout the process, the "two-end limiting" structure formed by the first baffle 22 and the second baffle 23 provides installation space for each component and provides lateral protection for the macro-drive 2 through the second baffle 23, ensuring the safety of the device operation.

[0075] It should be noted that, for those skilled in the art, it is obvious that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this utility model is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0076] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An in-situ mechanical experimental apparatus, characterized in that, include: The macro-motion coarse adjustment module includes a worktable (1), a macro-motion drive (2) and a lead screw (3). The output end of the macro-motion drive (2) is connected to the lead screw (3) for transmission. The worktable (1) and the lead screw (3) are in transmission cooperation. A micro-motion fine-tuning module is provided on the workbench (1). The micro-motion fine-tuning module includes a micro-motion base (5), a micro-drive component (6), a flexible hinge, and a mover (7). The micro-motion base (5) has an installation groove (8). The main body of the micro-drive component (6) is embedded in the installation groove (8), and the driving end of the micro-drive component (6) protrudes from the micro-motion base (5). The flexible hinge includes a first elastic beam structure (9) and a second elastic beam structure (10) symmetrically connected to both sides of the mover (7). The fixed ends of the first elastic beam structure (9) and the second elastic beam structure (10) are fixedly connected to the side wall of the micro-motion base (5). The driving end of the micro-drive component (6) is connected to the mover (7). The pressure head assembly includes a pressure head seat (11) and a pressure head (12). The driving end of the micro-drive (6) is connected to the pressure head seat (11) through the mover (7). The top of the pressure head seat (11) is rigidly connected to the pressure head (12). And a sample fixing device (4) for fixing the sample to be tested, wherein the sample fixing area of ​​the sample fixing device (4) is arranged opposite to the pressure head (12).

2. The in-situ mechanical experimental apparatus according to claim 1, characterized in that, Both the first elastic beam structure (9) and the second elastic beam structure (10) include a right-angle flexible structure, which includes at least two connecting beams (14); and adjacent connecting beams (14) are connected by connecting longitudinal arms (13), the axis of which is perpendicular to the axis of the connecting beams (14).

3. The in-situ mechanical experimental apparatus according to claim 2, characterized in that, The connecting beam (14) at the outer end is fixedly connected to the side wall of the micro-motion seat (5) through the connecting seat (15), and the connecting beam (14) at the inner end is fixedly connected to the side wall of the mover (7) as the movable end. A preset gap is reserved between the connecting longitudinal arm (13) and the connecting beam (14) and the micro-motion seat (5).

4. The in-situ mechanical experimental apparatus according to claim 1, characterized in that, The macro-motion coarse adjustment module also includes a guide rail (16) and a transmission seat (17); the guide rail (16) is set on the base, and the axis of the guide rail (16) is parallel to the axis of the lead screw (3); the transmission seat (17) is sleeved on the outside of the lead screw (3) and threadedly engaged with the lead screw (3) to form a threaded pair; the transmission seat (17) is fixedly connected to the worktable (1); the lower surface of the worktable (1) is slidably engaged with the guide rail (16) through a slider (18).

5. The in-situ mechanical experimental apparatus according to claim 4, characterized in that, The base is provided with a support seat, which includes two symmetrically arranged bosses (19) and a groove (20) located between the two bosses (19); the top surface of each boss (19) is equipped with a guide rail (16); the axis of the groove (20) in the length direction is parallel to the axis of the guide rail (16), and the lead screw (3) is arranged along the axial direction of the groove (20).

6. The in-situ mechanical experimental apparatus according to claim 5, characterized in that, The lead screw (3) is provided with a support seat (21) at one end away from the macro drive component (2). The support seat (21) is located in the groove (20). The bottom of the support seat (21) is fixedly connected to the bottom surface of the groove (20). A bearing is provided on the support seat (21). The inner ring of the bearing is connected to the shaft end of the lead screw (3).

7. The in-situ mechanical experimental apparatus according to claim 6, characterized in that, Two sliders (18) are spaced apart on the guide rail (16) on the top surface of each boss (19).

8. The in-situ mechanical experimental apparatus according to claim 7, characterized in that, A support member (1801) is fixedly provided on the outer wall of the slider (18); the top surface of the support member (1801) is in contact with the bottom surface of the worktable (1) to form a surface contact support; the worktable (1) and the slider (18) are fixedly connected by bolts.

9. The in-situ mechanical experimental apparatus according to claim 5, characterized in that, The base is provided with a first baffle (22) and a second baffle (23) at its two ends along its length direction. The first baffle (22) and the second baffle (23) are both spaced apart from the support seat. The sample fixing device (4) is fixed on the side end face of the first baffle (22) facing the support seat. The macro drive (2) is disposed between the second baffle (23) and the support seat.

10. The in-situ mechanical experimental apparatus according to claim 1, characterized in that, The pressure head includes a conical head (1201) with an arcuate end.

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