A rotatable micro-scale in-situ material testing system

Abstract

The present invention discloses a rotatable miniature in-situ material testing system, which comprises a high-rigidity mainframe frame, a transmission system, a control system, a real-time data acquisition unit, a third-party synchrotron radiation X-ray system and a third-party synchrotron DIC system. The transmission system comprises a high-precision reciprocating linear motion mechanism and a rotary motion mechanism: the linear motion mechanism is used to perform tests including stretching, compression, unloading and reloading, and fatigue damage on material samples; the rotary motion mechanism is used to perform stepless rotation according to the test requirements of the third-party synchrotron radiation X-ray system, so that the material sample can be penetrated by the third-party synchrotron radiation X-ray system without obstacles within the effective field of view height; the present invention solves the problem that when the transmission method performs material mechanics tests, only monotonous tensile tests can be performed but compression tests cannot be performed; and solves the problem that when the prior art requires a CT machine to scan material samples, barrier-free scanning cannot be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of material mechanics experiments and tests, and in particular relates to a rotatable micro-sized in-situ material testing system. Background Art

[0002] In-situ CT technology is one of the key technologies for cross-scale mechanical characterization of materials, and the most critical step in this technology is to develop a rotatable micro-in-situ material testing system that can be used in conjunction with a non-contact DIC system and a high-precision synchrotron radiation X-ray system. The stability and reliability of the performance of a rotatable micro-in-situ material testing system is directly related to the level of mechanical characterization of materials.

[0003] However, the rotatable micro-in-situ material testing system is not a proportional reduction of the traditional large-scale standard material testing machine. It has its own unique properties, such as self-rotation during loading and the material being free of obstacles within the effective field of view height for CT penetration. As a result, the test bench built using the design ideas of the traditional large-scale standard material testing machine cannot meet the testing requirements of in-situ CT of materials.

[0004] The rotatable micro-in-situ material testing system is a non-standard product. There is little relevant standard information in China, and there is a lack of design ideas that can be used for reference. The only way is to explore design solutions based on relevant test theories and experience, which increases the difficulty of the design of the test and test system to a certain extent. In addition, the micro-in-situ material testing systems commonly used in the existing market are mostly simple devices, which can only be used to implement monotonic tensile tests on materials and roughly measure their tensile forces. There is no test of material compression, unloading and reloading, and dynamic fatigue damage performance, and there is no standardized data acquisition and processing system. As a result, the in-situ material testing system, data acquisition and processing system, third-party non-contact DIC system, and high-precision synchrotron radiation X-ray system are independent of each other and can only be manually triggered and operated, which will inevitably lead to the inaccurate correspondence of stress, strain and other test data on the time scale, which brings great difficulties to the mechanical characterization and evaluation of materials.

[0005] The problems with the in-situ material testing system of the prior art are: first, it can only perform relatively simple tensile tests, and cannot perform relatively complex tests including compression / unloading and reloading / fatigue damage. Because in the relatively complex compression / unloading and reloading / fatigue damage test, the two ends of the material sample are squeezed toward the middle during the force application process, and the upper and lower ends of the material sample are required to be highly aligned. Once the two ends of the material sample deviate from the center line of the axis, additional bending moment force will be generated between the two ends. This bending moment force will act on the material sample and cause inaccuracy of the material sample or fracture of the material sample. Since the prior art has not been able to find a way to prevent the generation of additional bending moment force, for a long time, the in-situ material testing system can only perform simple tensile tests. Second, the in-situ material testing system test equipment of the prior art cannot be penetrated unimpeded by a third-party CT machine when it rotates 360 degrees. Because the test equipment is equipped with multiple thick high-rigidity steel columns at the four corners as the main support frame, these thick steel columns become obstructions to the CT scanner during the 360-degree rotation, blocking the CT scanning line of sight. Therefore, when it is necessary to perform CT scanning on the material sample, the equipment can only be stopped when the test reaches a certain level, and then the material sample can be removed from the test machine and scanned on the CT scanning equipment. This causes the material sample for CT scanning to no longer be in its original state, and it cannot be scanned synchronously by a third-party CT scanning system during the test. Summary of the invention

[0006] In order to solve the problems of the prior art, the present invention proposes a rotatable micro-in-situ material testing system. The first purpose is to solve the problem that the existing in-situ material testing system can only perform relatively simple tensile tests but cannot perform relatively complex compression / unloading and reloading / fatigue damage mode tests; the second purpose is to solve the problem that the in-situ material testing system of the prior art cannot achieve 360-degree obstacle-free rotation in conjunction with a third-party CT scan.

[0007] The present invention proposes the following technical solutions to solve the technical problems:

[0008] A rotatable micro-sized in-situ material testing system, the system comprises a high-rigidity mainframe frame subsystem, a transmission subsystem, a control subsystem, a real-time data acquisition unit, and a third-party synchrotron radiation X-ray system and a third-party synchronous DIC non-contact full-field strain measurement system; the high-rigidity mainframe frame subsystem is used to support and connect the transmission subsystem and the control subsystem respectively; the transmission subsystem comprises a high-precision reciprocating linear motion mechanism and a rotary motion mechanism; the real-time data acquisition unit is used to send the collected data of the pressure sensor 4-1 and the displacement sensor 4-2 to the control subsystem; the control subsystem is used to start or stop the high-precision reciprocating linear motion mechanism and the rotary motion mechanism of the transmission subsystem, and send trigger and stop signals to the third-party synchrotron radiation X-ray system and the third-party synchronous DIC non-contact full-field strain measurement system; it is characterized in that:

[0009] The high-precision reciprocating linear motion mechanism is used to perform tests including tension, compression, unloading and reloading, and fatigue damage on material samples; the rotary motion mechanism is used to drive the high-rigidity host frame subsystem together with the material sample to perform stepless rotation according to the test requirements of the third-party synchrotron radiation X-ray system, so that the material sample can be penetrated by the third-party synchrotron radiation X-ray system without obstacles within the effective field of view height;

[0010] The control subsystem flexibly sets and controls the trajectory of compression, unloading and reloading, and fatigue damage tests in addition to the tensile test, and flexibly sets and controls the rotation interval time of the rotary motion mechanism.

[0011] Furthermore, the high-rigidity mainframe frame subsystem is composed, from top to bottom, of a top tie rod 1-6, a self-aligning ball head assembly around the top tie rod 1-6, a replaceable tie rod 1-7 at the lower end of the top tie rod 1-6, a cylindrical high-precision quartz glass bearing assembly 1-1, an anti-rotation disk 1-2, a bearing seat 1-3, a motor mounting seat 1-4, and a base 1-5; the upper portion of the quartz glass bearing assembly 1-1 is connected to the top tie rod 1-6 and the self-aligning ball head assembly, and the bottom portion is connected to the anti-rotation disk 1-2, the anti-rotation disk 1-2 is used to limit the lifting rod 2-4 to only translate upward or downward when the motor of the high-precision reciprocating linear motion mechanism rotates, the lifting rod 2-4 passes through the center of the anti-rotation disk 1-2, and the contact surface between the lifting rod 2-4 and the anti-rotation disk 1-2 is a plane, and the two constitute a moving pair.

[0012] Furthermore, the self-aligning ball head assembly includes a self-aligning ball head 1-8 and a self-aligning ball head accessory, wherein the self-aligning ball head accessory includes a ball head pressure plate 1-8-1 tightly attached to the upper surface of the self-aligning ball head 1-8, a ball head base plate 1-8-2 tightly attached to the lower surface of the self-aligning ball head 1-8, and a spline nut 1-8-3 and a spline nut 2 1-8-4; the top pull rod 1-6 passes through the center of the self-aligning ball head 1-8, and the top pull rod 1-6 exposes the upper and lower local areas of the self-aligning ball head 1-8 as external threads, which are tightened by the spline nut 1-8-3 and the spline nut 2 1-8-4.

[0013] Furthermore, the top tie rod 1-6 and the self-aligning ball head 1-8 form a whole, and the self-aligning ball head 1-8 can rotate in the ball head socket composed of the ball head base plate 1-8-2 and the ball head pressure plate 1-8-1, so that the lower replaceable tie rod 1-7 can be deflected at a certain angle relative to its vertical center line, ensuring that it is not affected by additional bending moment when pulling / pressing the specimen.

[0014] Furthermore, the anti-rotation disk 1-2 has 6 pressure blocks 1-2-1 and 6 limit blocks 1-2-2 evenly distributed on its upper edge, 4 weight-reducing holes 1-2-4 are opened inside, and the countersunk hole 1-2-3 is used to install screws so as to be connected and fastened with the bearing seat 1-3 at the bottom. 6 evenly distributed notches are opened on the edge of the bottom flange of the quartz glass bearing component 1-1, and the circumferential width of the notches is slightly larger than the width of both sides of the pressure blocks and limit blocks of the anti-rotation disk 1-2; during installation, the notches of the quartz glass bearing component 1-1 are aligned with the pressure blocks and limit blocks, and after passing through, the bottom plane of the flange is tightly attached to the top surface of the anti-rotation disk; the quartz glass bearing component 1-1 is rotated clockwise, and its bottom flange is just pressed by the pressure block until it stops by the limited block, thereby realizing the quick connection of the quartz glass cover and the anti-rotation disk.

[0015] Furthermore, the high-precision reciprocating linear motion mechanism for testing strip materials comprises a motor bracket 2-1, a fully digital servo motor system 2-2, a screw sleeve 2-3, a lifting rod 2-4, an anti-rotation plate 1-2 and a bearing seat 1-3; the fully digital servo motor system 2-2 drives a spiral pair consisting of a screw sleeve 2-3 and a lifting rod 2-4, and the spiral pair cooperates with the anti-rotation plate 1-2 to limit the lifting rod 2-4 to only be able to translate upward or downward, thereby converting rotational motion into linear motion, realizing the function of pulling / compressing specimens and outputting tension or pressure and displacement values ​​in real time; the screw sleeve 2-3 and the lifting rod 2-4 are threadedly connected.

[0016] Furthermore, when performing a tensile test on a material sample, the sample is installed between the replaceable pull rod 1-7 and the lifting rod 2-4, and the fully digital servo motor system 2-2 rotates forward, driving the screw sleeve 2-3 to rotate. Under the restriction of the anti-rotation disk 1-2, the lifting rod 2-4 can only translate downward, the sample is pulled, and the pressure sensor measures and outputs the tension data in real time.

[0017] Furthermore, when doing a compression test on a material sample, the fully digital servo motor system 2-2 reverses, driving the screw sleeve 2-3 to rotate. Under the restriction of the anti-rotation disk 1-2, the lifting rod 2-4 can only translate upward, the sample is compressed, and the pressure sensor measures and outputs the tension data in real time.

[0018] Furthermore, when performing material unloading and reloading, as well as specimen fatigue testing, the fully digital servo motor system 2-2 rotates forward / reverse, driving the screw sleeve 2-3 to rotate. Under the restriction of the anti-rotation disk 1-2, the lifting rod 2-4 translates upward / downward, and the specimen experiences tensile / compressive loads. The pressure sensor measures and outputs tensile / compressive load data in real time.

[0019] Furthermore, the rotating mechanism for driving the high-rigidity main frame together with the material sample to rotate steplessly includes a fully digital servo motor 3-1, a worm 3-2, a worm bracket 3-3, a worm wheel 3-4, a motor mounting seat 1-4, and a bearing seat 1-3; the worm 3-2 is driven by the fully digital servo motor 3-1, which drives the worm wheel 3-4 to rotate, and all components except the base 1-5 rotate steplessly accordingly.

[0020] Furthermore, the control subsystem includes: a stretching / compression / unloading reloading / fatigue mode selection module, a setting force / displacement module, a real-time data acquisition and receiving module, a force / displacement control mode selection module, a third-party trigger and stop command module, a start or stop linear motion mechanism / rotational motion mechanism module, and a central processing module; the central processing module receives data from the stretching / compression / unloading reloading / fatigue mode selection module to control whether the full digital servo motor system 2-2 is currently performing forward operation or reverse operation; according to the data of the setting force / displacement and real-time data acquisition and receiving modules, the controlled pressure or displacement of the current material sample is closed-loop controlled; according to the progress of the current material sample in the pressure interval / displacement interval fed back by the real-time data acquisition and receiving module, the linear motion mechanism / rotational motion mechanism is started or stopped, and trigger and stop commands are sent to the third party; according to the force / displacement control mode selection, it is determined whether the closed-loop control method is force closed-loop control or displacement closed-loop control.

[0021] Advantages and effects of the present invention

[0022] 1. The present invention adopts a reciprocating linear motion mechanism of a linear motor + an anti-rotating disk, which solves the problem that only monotonous tensile tests can be performed but not compression tests when testing material samples using the traditional method; and solves the problem of additional bending moments generated during complex tests such as compression / unloading and reloading / fatigue tests of material samples through the self-aligning ball head assembly, and solves the worry that the material sample may break when the maximum bearing capacity is loaded during complex tests. Thus, the existing technology material samples can only have a simple tensile test, which is expanded to include multiple tests such as compression / unloading and reloading / fatigue tests, and solves the problem that the micro-in-situ material testing systems commonly used in the current market are mostly simple devices, which can only be used to implement monotonous tensile tests on materials and roughly measure their tensile forces, and do not test the compression, unloading and reloading, and fatigue damage performance of the materials, achieving a leap from quantitative change to qualitative change.

[0023] 2. The present invention organically combines a reciprocating linear motion mechanism, a rotary motion mechanism, a self-aligning ball head assembly, a control subsystem, and a high-rigidity mainframe bracket, and realizes that the control subsystem randomly sends trigger instructions and stop instructions to a third-party CT system, thereby solving the problem in the prior art that when a CT machine is required to scan material samples, it cannot achieve barrier-free scanning and can only be shut down first, and then the material test material must be taken down and scanned on the CT, which is very inefficient; it also enables the third-party CT system to scan not only the results of simple tensile tests, but also the results of complex tests such as compression / unloading and reloading / fatigue damage tests, and solves the problem of accurate correspondence between multiple test quantities in the system on a time scale, achieving a leap from quantitative change to qualitative change. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1-1 This is a framework diagram of the micro-sized in-situ material testing system of the present invention;

[0025] Figure 1-2 This is a block diagram of the control subsystem of the present invention;

[0026] Figure 2 Schematic diagram of the closed-loop control subsystem of the present invention;

[0027] Figure 3 A schematic diagram showing the relationship between the system of the present invention and a third-party synchrotron radiation / DIC system;

[0028] Figure 4-1 This is a three-dimensional diagram of the structure of the high-rigidity mainframe frame and the transmission subsystem of the present invention;

[0029] Figure 4-2 This is a cross-sectional view of the high-rigidity mainframe frame and transmission subsystem structure of the present invention;

[0030] Figure 4-3 This is a partial enlarged view of the high-rigidity mainframe frame and transmission subsystem structure of the present invention;

[0031] Figure 5 It is a schematic diagram of the anti-rotation disc of the present invention;

[0032] Figure 6 This is a schematic diagram of a quartz glass bearing assembly of the present invention;

[0033] Figure 7 This is a schematic diagram of the matching process of the quartz glass bearing assembly and the anti-rotation disk of the present invention;

[0034] Figure 8-1 It is a schematic diagram of the tensile test of the present invention;

[0035] Figure 8-2 It is a schematic diagram of the compression test of the present invention;

[0036] Fig. 9 This is a schematic diagram of an unloading and reloading test of the present invention;

[0037] Fig.10 This is a schematic diagram of the fatigue damage test of the present invention;

[0038] In the figure: 1-1: quartz glass bearing assembly; 1-2: anti-rotation plate; 1-2-1: pressure block; 1-2-2: limit block; 1-2-3: countersink; 1-2-4: weight reduction hole; 1-3: bearing seat; 1-4: motor mounting seat; 1-5: base; 1-6: top pull rod; 1-7: replaceable pull rod; 1-8: self-aligning ball head; 1-8-1: ball head pressure plate; 1-8-2: ball head bottom plate; 1-8-3: spline nut one; 1-8-4: spline nut two; 2-1: motor bracket; 2-2: full digital servo motor system; 2-3: screw sleeve; 2-4: lifting rod; 3-1: full digital servo motor; 3-2: worm; 3-3: worm bracket; 3-4: worm wheel; 4-1: pressure sensor; 4-2: displacement sensor. DETAILED DESCRIPTION

[0039] The present invention will be further explained below in conjunction with the accompanying drawings.

[0040] Design principle of the present invention

[0041] 1. The original intention of the design of the present invention: The first point is to realize relatively complex tests including stretching, compression, dynamic unloading and reloading, fatigue damage, etc., to solve the problem that the existing technology can only perform simple tensile tests; the second point is to allow the material sample to be synchronously and unobstructedly penetrated by the third-party radiation X-ray system within the effective field of view. The first point and the second point are complementary to each other. Without one of them, the other has no meaning. If the CT scan is only for a relatively simple tensile test, it is of little significance. If there is no CT scan for complex material tests, the test effect cannot be verified. Therefore, the original intention of the design of the present invention is to realize the first point and the second point at the same time.

[0042] 2. Difficulties in the implementation of the present invention: One of the difficulties is that the high-rigidity quartz glass component, the self-aligning ball head component, the diameter of the lifting rod 2-4, the rigidity of the sleeve, and the torque of the servo motor system, these five parts jointly determine the maximum bearing capacity, and any problem among them will affect the realization of the maximum bearing capacity. The present invention uses a high-rigidity quartz glass component to replace the sturdy columns used for the four-corner support of the traditional material testing equipment. When the bearing capacity is maximum, if the high-rigidity quartz glass cover is too thin, the test bench is prone to deformation or even buckling. When the "house" itself tilts due to deformation, the material sample in the house also tilts. When the bearing capacity is maximum, this tilt is more obvious, resulting in the failure of the material sample test; if it is limited to focusing on the firmness and durability of the high-rigidity quartz glass component, although the "house" is firm, the material sample itself may deviate from the center line of the axis when the bearing capacity reaches the maximum in complex tests such as compression, dynamic unloading and reloading, and fatigue damage. The loading of the maximum bearing capacity is affected; even if the problem of misalignment of the two ends of the material is solved, the firmness of the "house" is also solved, but it is still necessary to solve the problem of misalignment of the two ends of the material. The output torque of the motor, the thread form / pitch of the lifting rod 2-4, and the sleeve must be coordinated. When the load-bearing capacity is maximum, it exceeds the rated torque of the servo motor and will cause the rotating shaft to break. There is no problem with the torque of the servo motor and the diameter of the shaft. If the sleeve breaks, it cannot protect the motor. When the sleeve cannot withstand the maximum load-bearing capacity, it will also cause damage to the motor shaft. The second difficulty lies in: complex material sample tests, such as the maximum stress load point, minimum stress load point, and unloading point in fatigue damage tests. The values ​​of these three points are not the only combination of positive, negative, and 0 standard tensile and compressive symmetry, but the maximum stress load, minimum stress load, and average load can be set according to the requirements of the fatigue test; the rotation interval of the rotating mechanism is not fixed, but is flexibly set according to needs, and the interval of the rotation motion can be dense or sparse. The prior art uses an eccentric shaft to realize the reciprocating motion of the lifting rod 2-4. Since the eccentric angle of the eccentric shaft is fixed, the reciprocating motion trajectory is also fixed. The reciprocating motion trajectory of the present invention needs to be flexibly set: it can be a monotonic tensile type, a monotonic tensile damage type, or a fatigue test sawtooth type, and these three types can be switched randomly; the prior art also uses an eccentric shaft + worm and turbine to realize reciprocating motion + rotational motion, but since the reciprocating motion trajectory is fixed, the material samples scanned by the third-party CT machine are also limited to two types of samples, tensile or compressed. For material samples with complex shapes such as "dynamic unloading and reloading, fatigue damage test" and complex trajectories, since the material samples of the prior art cannot run on complex trajectories, it is impossible for the third-party CT equipment to irradiate material samples with complex motion trajectories other than tension and compression.

[0043] 3. The solution of the present invention:

[0044] The solution to one of the difficulties: collaborative design from three aspects: power source, loading object, and quartz glass cover to ensure the determination of the maximum load-bearing capacity during the test. First, the design of the power source: the motor, lifting rod 2-4, and screw sleeve cooperate with each other: the motor torque when the maximum load-bearing force is set to meet the set requirements, and then the diameter of the lifting rod 2-4 when the maximum load-bearing force is set to meet the set requirements, and then the selection of the screw sleeve when the maximum load-bearing force is set to meet the set requirements, so that the screw sleeve plays a role in protecting the lifting rod 2-4; second, the design of the loading object: the self-aligning ball head assembly is set to include a self-aligning ball head and a self-aligning ball head accessory, which includes a ball head pressure plate, a ball head bottom plate, and a nut for fastening the pressure plate and the low plate; the top pull rod and the self-aligning ball head form a whole, and the self-aligning ball head can rotate in the ball head socket composed of the ball head bottom plate and the ball head pressure plate, so that the lower replaceable pull rod can be deflected at a certain angle relative to its vertical center line to ensure that the sample is not affected by additional bending moment when pulling / pressing. Third, the design of the shell: the calculated load on the quartz glass is much smaller than the compressive strength of the quartz glass. The above three aspects of the power source, the loading object, and the quartz glass cover support and depend on each other. If the stress of the power source cannot meet the maximum load-bearing capacity requirements, even if the loading object is not affected by the additional bending moment, the material test results at the maximum load-bearing capacity cannot be measured; if the diameter, thickness, and compressive strength of the quartz glass cover cannot meet the requirements at the maximum load-bearing capacity, the "house" will collapse. Although the loading object in the "house" can be fine-tuned using the self-aligning ball head assembly, it will be useless because it has exceeded the fine-tuning range of the self-aligning ball head assembly; if the "house" is strong and the power source also provides the maximum load-bearing capacity, the upper and lower ends of the loading object cannot be adjusted due to a certain angle relative to its vertical center line, and are subject to additional bending moments. The damage induced by this additional bending moment accumulates to a certain extent, such as when the fatigue test is repeated a million times, the material sample may break. At this time, even if there is no problem with the power source and the quartz glass cover, the test still fails. Therefore, the above three cannot exist independently but are interdependent.

[0045] The solution to the second difficulty: 1) The linear motion mechanism adopts the method of motor + lifting rod + anti-rotation disk. Since the anti-rotation disk only limits the downward or upward translation of the lifting rod, but does not limit the starting point and end point of the movement of the lifting rod, the starting point and end point of the movement of the lifting rod are controlled by the control subsystem, so the reciprocating motion trajectory can be a monotonic stretching type, a monotonic stretching damage type, a fatigue test sawtooth type, and other complex forms, which can solve the problem of complex reciprocating motion trajectories. 2) Due to the use of linear motion servo motor + lifting rod + anti-rotation disk + rotary motion servo motor + control subsystem, the control subsystem can stop linear motion and start rotary motion at set time intervals. Therefore, the third-party CT machine can not only scan material samples in simple tensile processes, but also scan material samples in complex forms such as "dynamic unloading and reloading, fatigue damage test".

[0046] Based on the above invention principle, the present invention designs a rotatable micro-sized in-situ material testing system. Figure 1-1 , Figure 1-2 , Figure 3 As shown, the system includes a high-rigidity mainframe frame subsystem, a transmission subsystem, a control subsystem, a real-time data acquisition unit, and a third-party synchrotron radiation X-ray system and a third-party synchronous DIC non-contact full-field strain measurement system; the high-rigidity mainframe frame subsystem is used to support and connect the transmission subsystem and the control subsystem respectively; the transmission subsystem includes a high-precision reciprocating linear motion mechanism and a rotary motion mechanism; the real-time data acquisition unit is used to send the collected data of the pressure sensor 4-1 and the displacement sensor 4-2 to the control subsystem; the control subsystem is used to start or stop the high-precision reciprocating linear motion mechanism and the rotary motion mechanism of the transmission subsystem, and send trigger and stop signals to the third-party synchrotron radiation X-ray system and the third-party synchronous DIC non-contact full-field strain measurement system;

[0047] Its features are:

[0048] The high-precision reciprocating linear motion mechanism is used to perform tests including tension, compression, unloading and reloading, and fatigue damage on the material sample; the rotary motion mechanism is used to drive the high-rigidity main frame together with the material sample to perform stepless rotation according to the test requirements of the third-party synchrotron radiation X-ray system, so that the material sample can be penetrated by the third-party synchrotron radiation X-ray system without obstacles within the effective field of view height;

[0049] The control subsystem flexibly sets and controls the trajectory of compression, unloading and reloading, and fatigue damage tests in addition to the tensile test, and flexibly sets and controls the rotation interval time of the rotary motion mechanism.

[0050] Supplementary Note 1:

[0051] 1. The tension, compression, unloading and reloading, and fatigue damage are respectively as follows: Figure 8-1 , 8-2 , Fig. 9 , Fig.10 As shown in the figure, the tensile and compression test curves are unidirectional pressure change curves. If the tensile direction is set as positive, the compression direction is reverse; the unloading and reloading test curves are shown in the figure. Fig. 9 The figure shows a bidirectional stress variation curve. The unloading is to reduce the stress from about 250 MPa to 0 MPa, and then stretch the stress from 0 MPa to about 250 MPa. When unloading, the full digital servo motor system 2-2 reverses, and when loading, the full digital servo motor system 2-2 rotates forward. The "fatigue damage" test curve is shown in FIG. Fig.10 As shown, the material sample is stretched to the maximum stress by the full digital servo motor system 2-2 rotating forward, and then the material sample is unloaded from the maximum stress to 0 stress by the full digital servo motor system 2-2 reversing, and then the full digital servo motor system 2-2 is reversed, from 0 stress to the reverse maximum stress, and the reverse maximum stress is the minimum stress in the forward direction, and the cycle is repeated. The number of fatigue damage tests is set according to the requirements, generally more than 1 million times, that is, Fig.10 The cumulative number of cycles on the horizontal axis reaches more than 1 million times.

[0052] 2. The fully digital servo motor system 2-2 includes a servo motor and a reducer. The servo motor is decelerated by the reducer and then drives the lifting rod 2-4 to perform linear motion.

[0053] The control subsystem can flexibly set and control the trajectory of compression, unloading and reloading, and fatigue damage tests in addition to the tensile test, and flexibly set and control the rotation interval time of the rotary motion mechanism.

[0054] The high rigidity host rack subsystem is as follows Figure 4-1 , Figure 4-2 As shown, from top to bottom, it is composed of a top tie rod 1-6, a self-aligning ball head assembly around the top tie rod 1-6, a replaceable tie rod 1-7 at the lower end of the top tie rod 1-6, a cylindrical high-precision quartz glass bearing assembly 1-1, an anti-rotation disk 1-2, a bearing seat 1-3, a motor mounting seat 1-4, and a base 1-5; the upper part of the quartz glass bearing assembly 1-1 is connected to the top tie rod 1-6 and the self-aligning ball head assembly, and the bottom is connected to the anti-rotation disk 1-2. The anti-rotation disk 1-2 is used to limit the lifting rod 2-4 to only translate upward or downward when the motor of the high-precision reciprocating linear motion mechanism rotates. The lifting rod 2-4 passes through the center of the anti-rotation disk 1-2, and the contact surface between the lifting rod 2-4 and the anti-rotation disk 1-2 is a plane, and the two constitute a moving pair.

[0055] The self-aligning ball head assembly is as follows Figure 4-3 As shown, it includes a self-aligning ball head 1-8 and a self-aligning ball head accessory, the self-aligning ball head accessory includes a ball head pressure plate 1-8-1 tightly attached to the upper surface of the self-aligning ball head 1-8, a ball head base plate 1-8-2 tightly attached to the lower surface of the self-aligning ball head 1-8, and a spline nut 1-8-3 and a spline nut 2 1-8-4; the top pull rod 1-6 passes through the center of the self-aligning ball head 1-8, and the upper and lower local areas of the top pull rod 1-6 exposed from the self-aligning ball head 1-8 are external threads, which are tightened by the spline nut 1-8-3 and the spline nut 2 1-8-4.

[0056] like Figure 4-2 As shown, the top tie rod 1-6 and the self-aligning ball head 1-8 form a whole. The self-aligning ball head 1-8 can rotate in the ball head socket composed of the ball head base plate 1-8-2 and the ball head pressure plate 1-8-1, so that the lower replaceable tie rod 1-7 can be deflected at a certain angle relative to its vertical center line to ensure that the sample is not affected by additional bending moment when being pulled / compressed.

[0057] The anti-rotation disc 1-2 is as follows Figure 5 As shown, 6 pressure blocks 1-2-1 and 6 limit blocks 1-2-2 are evenly distributed on its upper edge, 4 weight-reducing holes 1-2-4 are opened inside, and the countersunk hole 1-2-3 is used to install screws so as to connect and fasten with the bearing seat 1-3 at the bottom, as shown in FIG. Figure 6 , Figure 7 As shown, 6 evenly distributed notches are opened on the edge of the bottom flange of the quartz glass bearing component 1-1, and the circumferential width of the notches is slightly larger than the width of both sides of the pressing block and the limit block of the anti-rotation disk 1-2; during installation, the notches of the quartz glass bearing component 1-1 are aligned with the pressing block and the limit block, and after passing through, the bottom plane of the flange and the top surface of the anti-rotation disk are tightly attached; the quartz glass bearing component 1-1 is rotated clockwise, and its bottom flange is just pressed by the pressing block until it stops by being blocked by the limited block, thereby realizing the quick connection of the quartz glass cover and the anti-rotation disk.

[0058] The high-precision reciprocating linear motion mechanism for testing a strip is as follows: Figure 4-1 , 4-2 As shown, it includes a motor bracket 2-1, a full-digital servo motor system 2-2, a screw sleeve 2-3, a lifting rod 2-4, an anti-rotation plate 1-2 and a bearing seat 1-3; the full-digital servo motor system 2-2 drives a spiral pair composed of a screw sleeve 2-3 and a lifting rod 2-4, and the spiral pair cooperates with the anti-rotation plate 1-2 to limit the lifting rod 2-4 to only be able to translate upward or downward, thereby converting rotational motion into linear motion, realizing the function of pulling / pressing the sample, and outputting tension or pressure and displacement values ​​in real time; the screw sleeve 2-3 and the lifting rod 2-4 are threadedly connected.

[0059] When doing a tensile test on a material sample, the sample is installed between the replaceable pull rod 1-7 and the lifting rod 2-4, and the full digital servo motor system 2-2 rotates forward to drive the screw sleeve 2-3 to rotate. Under the restriction of the anti-rotation disk 1-2, the lifting rod 2-4 can only move downward, the sample is pulled, and the pressure sensor measures and outputs the tension data in real time.

[0060] When doing compression test on material sample, the full digital servo motor system 2-2 reverses, driving the screw sleeve 2-3 to rotate. Under the restriction of the anti-rotation plate 1-2, the lifting rod 2-4 can only translate upward, the sample is compressed, and the pressure sensor measures and outputs the tension data in real time.

[0061] When performing material unloading and reloading, as well as specimen fatigue testing, the fully digital servo motor system 2-2 rotates forward / reverse, driving the screw sleeve 2-3 to rotate. Under the restriction of the anti-rotation disk 1-2, the lifting rod 2-4 translates upward / downward, and the specimen experiences tensile / compressive loads. The pressure sensor measures and outputs tensile / compressive load data in real time.

[0062] The rotating mechanism for driving the high-rigidity mainframe frame and the material sample to perform stepless rotation is as follows: Figure 4-1 , 4-2 As shown, it includes a fully digital servo motor 3-1, a worm 3-2, a worm bracket 3-3, a worm wheel 3-4, a motor mounting seat 1-4, and a bearing seat 1-3; the worm 3-2 is driven by the fully digital servo motor 3-1, which drives the worm wheel 3-4 to rotate, and all parts except the base 1-5 rotate steplessly accordingly.

[0063] The control subsystem includes: a stretching / compression / unloading reloading / fatigue mode selection module, a setting force / displacement module, a real-time data acquisition and receiving module, a force / displacement control mode selection module, a third-party trigger and stop command module, a start or stop linear motion mechanism / rotational motion mechanism module, and a central processing module; the central processing module receives data from the stretching / compression / unloading reloading / fatigue mode selection module to control whether the full digital servo motor system 2-2 is currently performing forward operation or reverse operation; according to the data of the setting force / displacement and real-time data acquisition and receiving modules, the controlled pressure or displacement of the current material sample is closed-loop controlled; according to the progress of the current material sample in the pressure interval / displacement interval fed back by the real-time data acquisition and receiving module, the linear motion mechanism / rotational motion mechanism is started or stopped, and trigger and stop commands are sent to the third party; according to the force / displacement control mode selection, it is determined whether the closed-loop control method is force closed-loop control or displacement closed-loop control.

[0064] Supplementary Note 2

[0065] The control subsystem is a dual safety protection system such as Figure 2As shown, it includes: two closed-loop control subsystems, one is a closed-loop control subsystem based on force, and the other is a closed-loop control subsystem based on displacement. When one control mode is selected, the remaining mode automatically becomes the safety protection mode of the entire device.

[0066] The force-based closed-loop control subsystem is as follows Figure 2 As shown, it includes a pressure sensor 4-1, a full-digital servo motor system 2-2 and a full-digital servo motor 3-1, a microprocessor, a D / A converter, an A / D converter, a given force (set force of the control subsystem) signal module, and a controlled force signal acquisition module; the given force signal module, the microprocessor, the D / A converter, the full-digital servo motor system 2-2 and the full-digital servo motor 3-1, the material sample, the controlled force signal acquisition module (the controlled force signal acquisition module is a real-time data acquisition receiving module of the control subsystem), and the A / D converter together constitute a closed-loop feedback system, which compares the given force and the controlled force, thereby controlling the controlled force of the material sample.

[0067] The displacement-based closed-loop control subsystem is as follows Figure 2 As shown, it includes a displacement sensor 4-2, a full digital servo motor system 2-2 and a full digital servo motor 3-1, a microprocessor (central processing unit of the control subsystem), a D / A converter, an A / D converter, a given displacement module, and a controlled displacement signal acquisition module; the given displacement module (the set displacement of the control subsystem), the microprocessor (the central processing unit of the control subsystem), the D / A converter, the full digital servo motor system 2-2 and the full digital servo motor 3-1, the material sample, the controlled displacement signal acquisition module (the controlled displacement signal acquisition module is the real-time data acquisition receiving module of the control subsystem), and the A / D converter together constitute a closed-loop feedback system, which compares the data of the given displacement module and the controlled displacement module, thereby controlling the controlled displacement of the material sample.

[0068] Example 1: Design of maximum test load capacity

[0069] The maximum test load designed in this embodiment is no more than 5KN. The maximum test load capacity is jointly determined by the high-rigidity quartz glass component, the self-aligning ball head component, the diameter of the lifting rod 2-4 in the repeatable reciprocating motion mechanism, and the torque of the servo motor system. Any unreasonable selection or design of any component / assembly will affect the test load capacity of the entire system. That is, the thickness of the quartz glass component, the output torque of the servo motor system, and the thickness of the sleeve should be adjusted according to the maximum test load required for the test.

[0070] 1) Design of quartz glass cover: When the maximum test load is 5KN, the diameter of the quartz glass cover is designed to be 112mm and the thickness is 3mm. The calculated load on the quartz glass is 4.19 MPa, which is much smaller than the compressive strength of quartz glass, which is 785-1150 MPa. At this time, the strain value of the quartz glass cover is 0.5×10 -4 , meeting the precise testing requirements of material testing machines.

[0071] 2) Design of the self-aligning ball head assembly: The clearance between the self-aligning ball heads 1-8 and the ball head pressure plate and the ball head bottom plate of the self-aligning ball head assembly shall not be greater than 0.05mm;

[0072] 3) Design of the diameter of the lifting rod 2-4: For the reciprocating linear motion system, the diameter of the lifting rod 2-4 is designed to be 36mm, using a transmission trapezoidal metric coarse thread, and the transmission efficiency is 0.9.

[0073] 4) Design of motor torque: through The calculated torque of the motor is 15.92 N·m, which is less than the rated torque of 23.9 N·m of the currently selected Mitsubishi MITSUBISHI J4 series servo motor HG-SR. In addition, the rated speed is 2000 r / min, which meets the requirements of the fatigue test frequency.

[0074] 5) The threaded sleeve is a third-party product purchased from a third party, and its type selection matches the maximum test load of 5KN.

[0075] Example 2: A micro-scale in-situ material tension / compression test method

[0076] Using the above rotatable micro-sized in-situ material testing system, the present invention designs a micro-sized in-situ material tension / compression testing method as follows: comprising the following steps:

[0077] Step 1: Complete the initialization preparation work before the tension and compression test of the material sample;

[0078] The initialization work includes:

[0079] 1) Set the material sample mode to stress control mode or strain control mode;

[0080] 2) Set the maximum stress S of the material sample in the tension / compression test max and minimum stress S min ;

[0081] 3) Set the values ​​of stress / strain at each discrete point of the material sample on the coordinate axis;

[0082] 4) Installing the sample between the replaceable pull rod 1-7 and the lifting rod 2-4;

[0083] Step 2. Select the type of current test: tension, compression;

[0084] Step 3: If the current test type is selected as a tensile test, the control subsystem controls the linear motion mechanism full digital servo motor system 2-2 to rotate forward, driving the screw sleeve 2-3 to rotate; if the current test type is selected as a compression test, the control subsystem controls the linear motion mechanism full digital servo motor system 2-2 to rotate reversely, driving the screw sleeve 2-3 to rotate;

[0085] Step 4: When the tensile test is performed, the anti-rotation plate 1-2 restricts the lifting rod 2-4 to only move downward, and when the compression test is performed, the anti-rotation plate 1-2 restricts the lifting rod 2-4 to only move upward, thereby converting the rotational motion of the full digital servo motor system 2-2 into linear motion;

[0086] Step 5: Material specimens are subjected to tension / compression tests;

[0087] Step 6: When the two ends of the sample are misaligned and additional bending moments are generated during the pulling / pressing process, the self-aligning ball head 1-8 rotates in the ball head socket composed of the ball head bottom plate 1-8-2 and the ball head pressure plate 1-8-1, so that the lower replaceable pull rod 1-7 is tilted at a certain angle relative to its vertical center line to ensure that the sample is not affected by additional bending moments during pulling / pressing;

[0088] Step 7: The control subsystem determines whether the current stress value reaches the value of the next set stress / strain discrete point. If not, the control subsystem sends a trigger signal to the third-party synchronous DIC non-contact full-field strain measurement system, and the third-party synchronous DIC non-contact full-field strain measurement system takes a picture of the material sample between the previous stress discrete point and the next stress discrete point; at the same time, the control subsystem starts the closed-loop control subsystem to adjust the controlled force / displacement of the current material sample; the closed-loop control subsystem includes a force-based closed-loop control subsystem and a displacement-based closed-loop control word system;

[0089] Step 8: The control subsystem determines whether the current stress value reaches the value of the next set stress discrete point. If so, the control subsystem stops the linear motion mechanism, starts the rotary motion mechanism, and sends a trigger signal to the third-party synchrotron radiation X-ray system.

[0090] Step 9: The rotary motion mechanism drives the high-rigidity mainframe frame and the material sample to rotate steplessly. At the same time, the fully digital servo motor 3-1 of the rotary motion mechanism drives the worm 3-2, and the worm 3-2 drives the worm gear 3-4 to rotate. The worm gear 3-4 drives all components except the base 1-5 to rotate steplessly. At the same time, the third-party synchrotron radiation X-ray system takes 360-degree photos of the material sample at the current stress point.

[0091] Step 10: The control subsystem determines whether the current tensile / compressive stress value reaches the upper limit S of the stress test range. max Or the lower limit Smin If not, return to step 5. If the current tensile / compressive stress value reaches the upper limit S of the stress test interval max Or the lower limit S min , the test ends.

[0092] Furthermore, the high rigidity host rack subsystem is as follows Figure 4-1 , 4-2 As shown, from top to bottom, it is composed of a top tie rod 1-6, a self-aligning ball head assembly around the top tie rod 1-6, a replaceable tie rod 1-7 at the lower end of the top tie rod 1-6, a cylindrical high-precision quartz glass bearing assembly 1-1, an anti-rotation disk 1-2, a bearing seat 1-3, a motor mounting seat 1-4, and a base 1-5; the upper part of the quartz glass bearing assembly 1-1 is connected to the top tie rod 1-6 and the self-aligning ball head assembly, and the bottom is connected to the anti-rotation disk 1-2. The anti-rotation disk 1-2 is used to limit the lifting rod 1-6 to only translate upward or downward when the motor of the high-precision reciprocating linear motion mechanism rotates. The lifting rod 2-4 passes through the center of the anti-rotation disk 1-2, and the contact surface between the lifting rod 2-4 and the anti-rotation disk 1-2 is a plane, and the two constitute a moving pair.

[0093] Furthermore, the self-aligning ball head assembly is as follows Figure 4-3 As shown, it includes a self-aligning ball head 1-8 and a self-aligning ball head accessory, the self-aligning ball head accessory includes a ball head pressure plate 1-8-1 tightly attached to the upper surface of the self-aligning ball head 1-8, a ball head base plate 1-8-2 tightly attached to the lower surface of the self-aligning ball head 1-8), and a spline nut 1-8-3 and a spline nut 2 1-8-4; the top pull rod 1-6 passes through the center of the self-aligning ball head 1-8, and the upper and lower local areas of the top pull rod 1-6 exposed from the self-aligning ball head 1-8 are external threads, which are tightened by the spline nut 1-8-3 and the spline nut 2 1-8-4.

[0094] Furthermore, if Figure 4-3 As shown, the top tie rod 1-6 and the self-aligning ball head 1-8 form a whole. The self-aligning ball head 1-8 can rotate in the ball head socket composed of the ball head base plate 1-8-2 and the ball head pressure plate 1-8-1, so that the lower replaceable tie rod 1-7 can be deflected at a certain angle relative to its vertical center line to ensure that the sample is not affected by additional bending moment when being pulled / compressed.

[0095] Example 3: A micro-scale in-situ material fatigue test method

[0096] Using the above rotatable micro-sized in-situ material testing system, the present invention designs a micro-sized in-situ material fatigue testing method, comprising the following steps:

[0097] Step 1: Complete the initialization preparation work before the fatigue test of the material sample;

[0098] The initialization work includes:

[0099] 1) Setting the frequency of fatigue test; the frequency refers to the number of cycles completed per second, and the cycle is: stretching, unloading, compression, and unloading again as one cycle;

[0100] 2) Set the mode of the material sample to be stress control mode or strain control mode;

[0101] 3) Set the stress ratio R, S of the material sample max and S min , where R = S min / S max ,S max and S min are the maximum stress and minimum stress experienced by the material test during the fatigue cycle, respectively;

[0102] 4) Set the fatigue limit N according to your needs f ;

[0103] 5) Scheduled CT scans weekly number N CT_1 、N CT_2 ,……,N CT_i ;

[0104] 6) Predetermine the number of cycles N for DIC non-contact full-field strain measurement DIC_1 、N DIC_2 ,……,N DIC_j In principle, N CT_i With N DIC_j The difference is within 5 cycles;

[0105] 7) Installing the sample between the replaceable pull rod 1-7) and the lifting rod 2-4;

[0106] Step 2: Stretch the current material sample. The stress in this stage is (S max +S min ) / 2 changes to S max ;

[0107] Step 3: Unload the current material sample. In this stage, the stress changes from S max Change to (S max +S min ) / 2;

[0108] Step 4: compress the current material sample. The stress in this stage changes from (S max +S min ) / 2 changes to S min ;

[0109] Step 5: Re-unload the current material sample. In this stage, the stress changes from S minChange to (S max +S min ) / 2;

[0110] Step 6: Re-stretch the current material sample. The stress at this stage is (S max +S min ) / 2 changes to S max ;

[0111] Step 7: The central processing unit of the control subsystem adds 1 to the number of fatigue test completions;

[0112] Step 8: The control subsystem determines whether the current accumulated cycle number reaches the predetermined CT scanning cycle number. If so, the control subsystem stops the linear motion mechanism, starts the rotary motion mechanism, and sends a trigger signal to the third-party synchrotron radiation X-ray system.

[0113] Step 9: The rotary motion mechanism drives the high-rigidity mainframe frame and the material sample to rotate steplessly. At the same time, the fully digital servo motor 3-1 of the rotary motion mechanism drives the worm 3-2, and the worm 3-2 drives the worm gear 3-4 to rotate. The worm gear 3-4 drives all components except the base 1-5 to rotate steplessly. At the same time, the third-party synchrotron radiation X-ray system takes 360-degree photos of the material sample at the current stress point.

[0114] Step 10: The control subsystem determines whether the current cumulative cycle number reaches the predetermined CT scanning cycle number. If not, the control subsystem continues to perform the above-mentioned cycle actions of step 2 to step 5 until the material sample is fatigue-fractured or the cumulative cycle number reaches the predetermined fatigue limit.

[0115] The step 2 of stretching the current material sample is specifically as follows: the control subsystem starts the full digital servo motor system 2-2 of the linear motion mechanism to rotate forward, and during the stretching process, the stress changes from (S max +S min ) / 2 changes to S max ;

[0116] The step 3 of unloading the current material sample is as follows: the control subsystem starts the full digital servo motor system 2-2 of the linear motion mechanism to reverse, and during the unloading process, the stress changes from S max becomes (S max +S min ) / 2;

[0117] The fourth step of compressing the current material sample is as follows: the control subsystem controls the full digital servo motor system 2-2 of the linear motion mechanism to continue to reverse, and during the reverse compression process, the stress changes from (S max +S min ) / 2 changes to S min ;

[0118] The step 5 of re-unloading the current material sample is as follows: the control subsystem controls the all-digital servo motor system 2-2 of the linear motion mechanism to change from reverse to forward rotation, and during the re-unloading process, the stress changes from S min Change to (S max +S min ) / 2;

[0119] The step six of re-stretching the current material sample is specifically as follows: the control subsystem controls the full digital servo motor system 2-2 of the linear motion mechanism to continue to rotate forward, and during the re-stretching process, the stress is (S max +S min ) / 2 changes to S max ;

[0120] In the steps 2 to 6, the control subsystem controls the full digital servo motor system 2-2 of the linear motion mechanism to rotate forward or reverse, driving the screw sleeve 2-3 to rotate. When the screw sleeve 2-3 rotates,

[0121] 1) The anti-rotation plate 1-2 restricts the lifting rod 2-4 to only translate upward or downward, thereby converting the rotational motion of the all-digital servo motor system 2-2 into a vertical upward or vertical downward linear motion;

[0122] 2) During the test of stretching, unloading, compression, re-unloading, and re-stretching, when the two ends of the specimen are affected by additional bending moments due to misalignment, the self-aligning ball head 1-8 rotates in the ball head socket composed of the ball head base plate 1-8-2 and the ball head pressure plate 1-8-1, so that the lower replaceable pull rod 1-7 is deflected at a certain angle relative to its vertical center line to ensure that the specimen is not affected by additional bending moments during stretching / compression;

[0123] Supplementary Note 3:

[0124] The method of the present invention is designed for fatigue damage test. The test principle of unloading and reloading is the same as that of fatigue damage test. Fig. 9 As shown, both are bidirectional stress loading, the difference is: in the fatigue damage test, reverse compression continues after unloading, that is, the servo motor continues to reverse, while in the unloading and reloading test, the servo motor no longer continues to reverse after unloading, but changes from reverse to forward rotation.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A rotatable miniature in-situ material testing system, which includes a high-rigidity mainframe subsystem, a transmission subsystem, a control subsystem, a real-time data acquisition unit, a third-party synchrotron radiation X-ray system, and a third-party synchronous DIC non-contact full-field strain measurement system; The high-rigidity host frame subsystem is used to support and connect the transmission subsystem and the control subsystem respectively; the transmission subsystem includes a high-precision reciprocating linear motion mechanism and a rotary motion mechanism; the real-time data acquisition unit is used to send the collected pressure sensor (4-1) and displacement sensor (4-2) data to the control subsystem; the control subsystem is used to start or stop the high-precision reciprocating linear motion mechanism and the rotary motion mechanism of the transmission subsystem, and send trigger and stop signals to a third-party synchrotron radiation X-ray system and a third-party synchrotron DIC non-contact full-field strain measurement system; Features: The high-precision reciprocating linear motion mechanism is used to perform tests including tension, compression, unloading and reloading, and fatigue damage on material samples; the rotary motion mechanism is used to drive the high-rigidity host frame subsystem together with the material sample to perform stepless rotation according to the test requirements of the third-party synchrotron radiation X-ray system, so that the material sample can be penetrated by the third-party synchrotron radiation X-ray system without obstacles within the effective field of view height; The control subsystem flexibly sets and controls the trajectory of compression, unloading and reloading, and fatigue damage tests in addition to the tensile test, and flexibly sets and controls the rotation interval time of the rotary motion mechanism; The high-rigidity mainframe frame subsystem is composed of, from top to bottom, a top tie rod (1-6), a self-aligning ball head assembly around the top tie rod (1-6), a replaceable tie rod (1-7) at the lower end of the top tie rod (1-6), a cylindrical high-precision quartz glass bearing assembly (1-1), an anti-rotation disk (1-2), a bearing seat (1-3), a motor mounting seat (1-4), and a base (1-5); the upper part of the quartz glass bearing assembly (1-1) is connected to the top tie rod (1-6) and the self-aligning ball head assembly, and the bottom is connected to the anti-rotation disk (1-2); the anti-rotation disk (1-2) is used to limit the lifting rod (2-4) to only translate upward or downward when the motor of the high-precision reciprocating linear motion mechanism rotates; the lifting rod (2-4) passes through the center of the anti-rotation disk (1-2), and the contact surface between the lifting rod (2-4) and the anti-rotation disk (1-2) is a plane, and the two constitute a moving pair; The maximum test load capacity is jointly determined by the high-precision quartz glass bearing assembly, the self-aligning ball head assembly, the diameter of the lifting rod (2-4) in the high-precision reciprocating linear motion mechanism, and the torque of the full digital servo motor system; when the maximum test load is not greater than 5KN, the designs of each item are as follows: 1) Design of high-precision quartz glass bearing assembly: When the maximum test load is 5KN, the diameter of the quartz glass cover is designed to be 112mm and the thickness is 3mm. The calculated load on the quartz glass is 4.19 MPa, which is much smaller than the compressive strength of quartz glass, which is 785-1150 MPa. At this time, the strain value of the quartz glass cover is 0.5×10 -4 , meet the precise testing requirements of material testing machines; 2) Design of the self-aligning ball head assembly: The clearance between the self-aligning ball head (1-8) and the ball head pressure plate, as well as the ball head base plate of the self-aligning ball head assembly shall not be greater than 0.05mm; 3) Design of the lifting rod diameter: For the reciprocating linear motion system, the lifting rod (2-4) is designed to have a diameter of 36 mm, using a transmission trapezoidal metric coarse thread, and a transmission efficiency of 0.9; 4) Design of motor torque: The motor torque is 15.92N·m, which is less than the rated torque of 23.9N·m of the currently selected Mitsubishi MITSUBISHI J4 series servo motor HG-SR. In addition, the rated speed is 2000r / min, which meets the requirements of fatigue test frequency; 5) The selection of the screw sleeve should match the maximum test load of 5KN; The self-aligning ball head assembly comprises a self-aligning ball head (1-8) and a self-aligning ball head accessory, wherein the self-aligning ball head accessory comprises a ball head pressure plate (1-8-1) closely attached to the upper surface of the self-aligning ball head (1-8), a ball head bottom plate (1-8-2) closely attached to the lower surface of the self-aligning ball head (1-8), and a spline nut 1 (1-8-3) and a spline nut 2 (1-8-4); the top tie rod (1-6) passes through the center of the self-aligning ball head (1-8), and the upper and lower local areas of the top tie rod (1-6) exposed from the self-aligning ball head (1-8) are external threads, which are tightened by the spline nut 1 (1-8-3) and the spline nut 2 (1-8-4); The top pull rod (1-6) and the self-aligning ball head (1-8) form a whole, and the self-aligning ball head (1-8) can rotate in a ball head socket composed of a ball head bottom plate (1-8-2) and a ball head pressure plate (1-8-1), so that the lower replaceable pull rod (1-7) can be deflected at a certain angle relative to its vertical center line, ensuring that the sample is not affected by additional bending moment when being pulled / pressed; The anti-rotation disc (1-2) has 6 evenly distributed pressure blocks (1-2-1) and 6 limit blocks (1-2-2) on the upper edge, 4 weight-reducing holes (1-2-4) are opened inside, and the countersunk holes (1-2-3) are used for mounting screws and connecting and fastening with the bearing seat at the bottom. The bottom flange edge of the quartz glass bearing component (1-1) has 6 evenly distributed notches, and the circumferential width of the notches is slightly larger than the width of both sides of the pressure blocks and limit blocks of the anti-rotation disc (1-2). During installation, the notches of the quartz glass bearing component (1-1) are aligned with the pressure blocks and limit blocks, and after passing through, the bottom plane of the flange and the top surface of the anti-rotation disc are closely attached. The quartz glass bearing component (1-1) is rotated clockwise, and its bottom flange is just pressed by the pressure blocks until it stops due to being blocked by the limit blocks, thereby realizing the quick connection between the quartz glass cover and the anti-rotation disc. The high-precision reciprocating linear motion mechanism comprises a motor bracket (2-1), a fully digital servo motor system (2-2), a screw sleeve (2-3), and a lifting rod (2-4); the fully digital servo motor system (2-2) drives a screw pair consisting of a screw sleeve (2-3) and a lifting rod (2-4); the screw pair cooperates with an anti-rotation plate (1-2) to limit the lifting rod (2-4) to only be able to move upward or downward, thereby converting rotational motion into linear motion, achieving the functions of pulling / pressing a sample and outputting tension or pressure and displacement values ​​in real time; the screw sleeve (2-3) and the lifting rod (2-4) are threadedly connected; When performing a tensile test on a material sample, the sample is installed between the replaceable pull rod (1-7) and the lifting rod (2-4), and the full digital servo motor system (2-2) rotates forward to drive the screw sleeve (2-3) to rotate. Under the restriction of the anti-rotation plate (1-2), the lifting rod (2-4) can only move downward, the sample is pulled, and the pressure sensor measures and outputs the tension data in real time; When performing a compression test on a material sample, the fully digital servo motor system (2-2) reverses to drive the screw sleeve (2-3) to rotate. Under the restriction of the anti-rotation plate (1-2), the lifting rod (2-4) can only move upward, the sample is compressed, and the pressure sensor measures and outputs the tension data in real time; When performing material unloading and reloading, as well as sample fatigue testing, the fully digital servo motor system (2-2) rotates forward / reverse, driving the screw sleeve (2-3) to rotate. Under the restriction of the anti-rotation plate (1-2), the lifting rod (2-4) translates upward / downward, and the sample experiences tensile / compressive loads. The pressure sensor measures and outputs tensile / compressive load data in real time. The rotary motion mechanism comprises a fully digital servo motor (3-1), a worm (3-2), a worm support (3-3), and a worm wheel (3-4); the fully digital servo motor (3-1) drives the worm (3-2), which drives the worm wheel (3-4) to rotate, and all parts except the base (1-5) rotate steplessly accordingly.

2. A rotatable micro-scale in-situ material testing system according to claim 1, Features: The control subsystem includes: a stretching / compression / unloading reloading / fatigue mode selection module, a setting force / displacement module, a real-time data acquisition receiving module, a force / displacement control mode selection module, a third-party trigger and stop command module, a start or stop linear motion mechanism / rotational motion mechanism module, and a central processing module; The central processing module receives data from the stretching / compression / unloading reloading / fatigue mode selection module, thereby controlling whether the fully digital servo motor system (2-2) is currently executing forward operation or reverse operation; based on the data of the set force / displacement and real-time data acquisition and receiving module, the controlled pressure or displacement of the current material sample is closed-loop controlled; based on the progress of the current material sample in the pressure range / displacement range fed back by the real-time data acquisition and receiving module, the linear motion mechanism / rotational motion mechanism is started or stopped, and trigger and stop instructions are sent to a third party; based on the force / displacement control mode selection, it is determined whether the closed-loop control method is force closed-loop control or displacement closed-loop control.

Images