A pulse current assisted tensile and compression self-centering test device

Abstract

The present invention provides a pulse current assisted tensile and compression self-centering test device, which belongs to the technical field of material mechanics tensile and compression performance testing equipment, including a testing machine, a clamping fixture, a compression mechanism, a clamping mechanism, an electrode sheet, an anti-buckling mechanism and a centering clamping mechanism, so that the clamping fixture is connected to the testing machine and clamps the sample, and the compression mechanism pulls the clamping mechanism to move, so that the clamping mechanism can clamp the electrode sheet, so that the electrode sheet can provide a pulse current to the sample; the anti-buckling mechanism slides against the sample and prevents the sample from buckling, and the centering clamping mechanism can keep the sample centered in the length direction. The pulse current assisted tensile and compression self-centering test device provided by the present invention can enable the sample to achieve self-centering, ensure the safety and accuracy of the tensile and compression test process, and thus promote the widespread application of pulse current assisted tensile and compression test technology in material mechanics performance testing.

Description

Technical Field

[0001] The present invention belongs to the technical field of material mechanics tensile and compression performance testing equipment, and more specifically, relates to a pulse current assisted tensile and compression self-centering testing device. Background Art

[0002] In the field of material mechanical testing, pulsed current-assisted tensile and compression testing is an important means of evaluating material mechanical properties (such as strength and ductility). Its core value lies in the synergy of electrical and mechanical energy, surpassing the inherent deformation limits of materials and achieving the advanced manufacturing goals of "lighter, stronger, and more efficient." With the rapid development of new energy, aerospace, and other fields, pulsed current-assisted forming technology will become a key technology for the development of high-performance materials and the formation of complex components.

[0003] Electric-assisted stretching can deeply explore the influence of pulsed current on solid-state phase transitions, systematically revealing the mechanism of microstructural evolution under current-assisted conditions and laying a solid theoretical foundation for electric-assisted forming processes. Electric-assisted compression, on the other hand, can manipulate material deformation behavior through current, studying microstructural changes under stress-electric-thermal coupling and helping to optimize compression forming process parameters for complex components. Both experiments involve the influence of multiple factors, including temperature fields, electromagnetic fields, and mechanical changes. These experiments expand the application boundaries of electric-assisted forming technology from different dimensions, providing important support for resolving the pain points of traditional hot forming processes and promoting the upgrading of materials processing and manufacturing technologies.

[0004] Currently, traditional tensile testing equipment applies tensile force to specimens through mechanical loading. Conventional test fixtures have limitations when performing pulsed current-assisted tensile and compression tests, such as the on / off state of the pulse current, the insulation between the tensile machine and the energized specimen, and the alignment of the specimen relative to the testing machine. These limitations restrict test accuracy and safety. With the growing demand for high-performance materials in fields such as new energy and aerospace, there is an urgent need to develop a test fixture that integrates current-assisted, self-aligned, and buckling-resistant features. Summary of the Invention

[0005] The purpose of the present invention is to provide a pulse current assisted tensile and compression self-centering test device, which aims to solve the technical problems that traditional tensile testing equipment applies tension to the specimen through mechanical loading, and traditional test fixtures have limitations when testing pulse current assisted tensile and compression tests.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a pulse current assisted tensile and compression self-centering test device, comprising:

[0007] A testing machine having an upper chuck and a lower chuck;

[0008] A clamping fixture connected to the upper clamp and the lower clamp, the clamping fixture being suitable for clamping and fixing both ends of the sample;

[0009] a compression mechanism connected to the clamping fixture, the compression mechanism having a telescopic end with a degree of freedom of extension and contraction along the thickness direction of the specimen;

[0010] a clamping mechanism connected to the telescopic end of the compression mechanism, wherein the clamping mechanism has the freedom to move along the thickness direction of the sample by means of the compression mechanism;

[0011] The electrode sheet includes an upper electrode sheet and a lower electrode sheet, wherein the clamping mechanism is used to clamp and fix the upper electrode sheet and the lower electrode sheet, and the compression mechanism is used to make the upper electrode sheet and the lower electrode sheet respectively stick to the side walls of the sample, so that the electrode sheet provides a pulse current to the sample;

[0012] an anti-buckling mechanism, disposed between the upper chuck and the lower chuck, the anti-buckling mechanism being adapted to slidably clamp the specimen and prevent the specimen from buckling during a compression test;

[0013] A centering clamping mechanism is connected to the upper clamp or the lower clamp, and is suitable for clamping the anti-buckling mechanism during a compression test and clamping the sample during a tensile test, so that the sample is centered in its length direction.

[0014] In one possible implementation, the clamping fixture includes:

[0015] an upper clamping fixture connected to the upper chuck and adapted to clamp and fix one end of the sample, wherein the clamping force of the upper clamping fixture on the sample is adjustable;

[0016] The lower clamping fixture is connected to the lower clamping head and is suitable for clamping and fixing the other end of the sample. The clamping force of the lower clamping fixture on the sample can be adjusted.

[0017] In a possible implementation, the upper clamping fixture includes an upper left fixed clamp body and an upper right fixed clamp body fixedly connected to the upper clamp head and spaced apart, the upper left fixed clamp body is connected to an upper left movable clamp body on a side close to the upper right fixed clamp body, and the upper right fixed clamp body is connected to an upper right movable clamp body on a side close to the upper left fixed clamp body, and a clamping space for the specimen is formed between the upper left movable clamp body and the upper right movable clamp body;

[0018] The lower clamping fixture includes a lower left fixed clamp body and a lower right fixed clamp body which are fixedly connected to the lower clamp head and are spaced apart. The lower left fixed clamp body is connected to a lower left movable clamp body on one side close to the lower right fixed clamp body, and the lower right fixed clamp body is connected to a lower right movable clamp body on one side close to the lower left fixed clamp body. A clamping space for the sample is formed between the lower left movable clamp body and the lower right movable clamp body.

[0019] In a possible implementation, the compression mechanism includes:

[0020] an upper external compression mechanism connected to the clamping fixture and proximate to the upper chuck;

[0021] an upper inner compression mechanism connected to the clamping fixture and close to the upper clamping head, and arranged in parallel with the upper outer compression mechanism in the horizontal direction;

[0022] a lower external compression mechanism connected to the clamping fixture and proximate to the lower clamp;

[0023] a lower inner compression mechanism connected to the clamping fixture and close to the lower chuck, and arranged in parallel with the lower outer compression mechanism in the horizontal direction; the upper outer compression mechanism, the upper inner compression mechanism, the lower outer compression mechanism and the lower inner compression mechanism all have a telescopic end with a degree of freedom of extension and contraction along the thickness direction of the sample, and the telescopic end is arranged close to the sample;

[0024] The upper outer compression mechanism and the upper inner compression mechanism are used to extend and retract toward one end of the sample, and the lower outer compression mechanism and the lower inner compression mechanism are used to extend and retract toward the other end of the sample.

[0025] In a possible implementation, the upper external compression mechanism, the upper internal compression mechanism, the lower external compression mechanism, and the lower internal compression mechanism all include:

[0026] A compression base with a cavity inside;

[0027] A telescopic shaft is located in the cavity and is slidably plugged into one side of the compression base, and the telescopic shaft has freedom of movement along its axial direction;

[0028] A compression spring is sleeved on the outside of the telescopic shaft, and the compression spring is used to pull the telescopic shaft to move along its axial direction toward the inner side of the compression base;

[0029] A bolt is connected to the compression base, and the bolt is used to limit one end of the compression spring.

[0030] In one possible implementation, the clamping mechanism includes:

[0031] A screw rail base, one end of which is connected to an end of the telescopic shaft extending out of the compression base, and the screw rail base has the freedom to move axially along the telescopic shaft by means of the telescopic shaft;

[0032] A lead screw chuck is connected to the lead screw slide base, and the lead screw chuck is suitable for clamping and fixing the upper electrode sheet or the lower electrode sheet. The lead screw chuck moves with the help of the telescopic shaft to make the upper electrode sheet or the lower electrode sheet stick to the side wall of the sample.

[0033] In one possible implementation, the anti-buckling mechanism includes:

[0034] Buckling restraint plates, in two groups, are installed on both sides of the specimen;

[0035] Two groups of wear-resistant smooth insulating plates are provided on both sides of the specimen, the two groups of wear-resistant smooth insulating plates are located inside the two groups of anti-buckling plates, and the wear-resistant smooth insulating plates are used to slide against the specimen;

[0036] a centering assembly connected to one side of the specimen and located between the wear-resistant smooth insulating plate and the anti-buckling plate, wherein the centering assembly is suitable for clamping the wear-resistant smooth insulating plate and the specimen;

[0037] There are multiple connecting bolts used to lock and fix the two sets of anti-buckling plates, the two sets of wear-resistant smooth insulating plates, and the centering assembly;

[0038] There are multiple support springs that are respectively sleeved on the outside of the multiple connecting bolts. The support springs are used to elastically push the anti-buckling plates and lock the two groups of anti-buckling plates.

[0039] In one possible implementation, the centering component includes:

[0040] a first tooth comb-shaped clamping guide plate;

[0041] A second tooth-comb-shaped clamping guide plate is slidably connected to the first tooth-comb-shaped clamping guide plate, and a space suitable for clamping the wear-resistant smooth insulating plate is formed between the second tooth-comb-shaped clamping guide plate and the first tooth-comb-shaped clamping guide plate;

[0042] A centering spring, both ends of which are respectively connected to the first tooth comb-shaped clamping guide plate and the second tooth comb-shaped clamping guide plate. The centering spring is used to pull the first tooth comb-shaped clamping guide plate and the second tooth comb-shaped clamping guide plate toward each other, thereby adjusting the space width.

[0043] In one possible implementation, the centering clamping mechanism includes:

[0044] A base, connected to the upper chuck or the lower chuck;

[0045] a first guide rod, one end of which is hinged to the base, the first guide rod having a degree of freedom of rotation about the hinged end;

[0046] a second guide rod, one end of which is rotatably connected to the other end of the first guide rod, the second guide rod having a degree of freedom of rotation about its rotation end;

[0047] A bidirectional screw clamping and centering assembly is connected to the other end of the second guide rod. The bidirectional screw clamping and centering assembly is suitable for clamping the anti-buckling mechanism during a compression test and clamping the sample during a tensile test so that the sample is centered in its length direction.

[0048] In one possible implementation, the bidirectional screw clamping and centering assembly includes:

[0049] a right clamp, one side of which is connected to the end of the second guide rod;

[0050] A left clamp, one end of which is hinged to the right clamp, and a clamping space suitable for clamping and fixing the anti-buckling mechanism is formed between the left clamp and the right clamp;

[0051] A bidirectional screw passes through and is simultaneously screwed to the left clamp and the right clamp, and the bidirectional screw is used to adjust the width of the clamping space between the left clamp and the right clamp.

[0052] The beneficial effects of a pulse current assisted tensile and compression self-centering test device provided by the present invention are as follows: compared with the prior art, the pulse current assisted tensile and compression self-centering test device provided by the present invention includes a testing machine, a clamping fixture, a compression mechanism, a clamping mechanism, an electrode sheet, an anti-buckling mechanism and a centering clamping mechanism. By clamping the specimen with the clamping fixture and using the compression mechanism to push the clamping mechanism, the clamping mechanism can clamp and fix the electrode sheet, the anti-buckling mechanism can prevent the specimen from buckling and deformation, and the centering clamping mechanism can keep the specimen centered in the length direction. The pulse current assisted tensile and compression self-centering test device provided by the present invention can enable the specimen to achieve self-centering, ensure the safety and accuracy of the tensile and compression test process, thereby promoting the widespread application of pulse current assisted tensile and compression test technology in material mechanical property testing, solving the technical problem that traditional test fixtures have limitations when testing pulse current assisted tensile and compression tests, and has the ability to integrate current assistance, self-centering and anti-buckling functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 A schematic structural diagram of a pulse current assisted tensile and compression self-centering test device provided in an embodiment of the present invention;

[0055] Figure 2 A schematic structural diagram of an upper chuck of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0056] Figure 3 A schematic structural diagram of a lower chuck of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0057] Figure 4 A schematic structural diagram of an upper clamping fixture of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0058] Figure 5 A schematic structural diagram of a lower clamping fixture of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0059] Figure 6 A schematic structural diagram of a compression mechanism and a clamping mechanism of a pulse current assisted tension-compression self-centering test device provided by an embodiment of the present invention;

[0060] Figure 7 A schematic diagram of the explosion structure of the anti-buckling mechanism of a pulse current assisted tension and compression self-centering test device provided by an embodiment of the present invention;

[0061] Figure 8 for Figure 7 Schematic diagram of the connection structure between the centering assembly and the anti-buckling plate;

[0062] Figure 9 for Figure 7 The diagram of the anti-buckling mechanism in use;

[0063] Figure 10 A schematic structural diagram of a centering assembly of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0064] Figure 11 A schematic structural diagram of a centering assembly of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0065] Figure 12 A schematic structural diagram of a centering clamping mechanism of a pulse current assisted tensile and compression self-centering test device provided by an embodiment of the present invention;

[0066] Figure 13 A schematic structural diagram of a bidirectional screw clamping centering assembly of a pulse current assisted tensile and compression self-centering test device provided in an embodiment of the present invention.

[0067] Description of reference numerals:

[0068] 1. Upper chuck;

[0069] 2. Lower chuck;

[0070] 3. Compression mechanism; 31. Upper external compression mechanism; 311. Compression base; 312. Telescopic shaft; 313. Compression spring; 314. Bolt; 32. Upper internal compression mechanism; 33. Lower external compression mechanism;

[0071] 4. Clamping mechanism; 41. Screw guide rail base; 42. Screw chuck;

[0072] 5. Electrode sheet; 51. Upper electrode sheet; 52. Lower electrode sheet; 53. Bolt hole;

[0073] 6. Anti-buckling mechanism; 61. Anti-buckling plate; 62. Wear-resistant smooth insulating plate; 63. Centering assembly; 631. First comb-shaped clamping guide plate; 632. Second comb-shaped clamping guide plate; 633. Centering spring; 64. Connecting bolt; 65. Support spring; 66. Perspective window;

[0074] 7. Centering clamping mechanism; 71. Base; 72. First guide rod; 73. Second guide rod; 74. Two-way bolt clamping and centering assembly; 741. Left clamp; 742. Right clamp; 743. Two-way screw;

[0075] 8. Upper clamping fixture; 81. Upper left fixed clamp; 82. Upper right fixed clamp; 83. Upper left movable clamp; 84. Upper right movable clamp;

[0076] 9. Lower clamping fixture; 91. Lower left fixed clamp; 92. Lower right fixed clamp; 93. Lower left movable clamp; 94. Lower right movable clamp;

[0077] 10. Sample. DETAILED DESCRIPTION

[0078] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0079] In material mechanics tests, the specimen is kept centered during tension and compression tests, which means that the axis of the specimen in the fixture or other fixture of the testing machine coincides with the loading axis of the testing machine. Simply put, the specimen must be placed straight and not skewed. The alignment of the load chain can be simply understood as whether the center lines of the force sensor, fixture, adapter and specimen are in a straight line. In tensile tests, if the alignment of the load chain is not good, the test sample will be subjected to additional deflection force during loading, resulting in uneven force and affecting the authenticity of the test results. Therefore, when testing specimen 10, it is necessary to keep specimen 10 centered, which will help improve the accuracy of the test results.

[0080] Please also refer to Figures 1 to 13, now the pulse current assisted tensile compression self-centering test device provided by the present invention is described. The pulse current assisted tensile compression self-centering test device includes a testing machine, a clamping fixture, a compression mechanism 3, a clamping mechanism 4, an electrode sheet 5, an anti-buckling mechanism 6 and a centering clamping mechanism 7. The testing machine has an upper chuck 1 and a lower chuck 2; the clamping fixture is connected to the upper chuck 1 and the lower chuck 2, and the clamping fixture is suitable for clamping and fixing the two ends of the sample 10; the compression mechanism 3 is connected to the clamping fixture, and the compression mechanism 3 has a telescopic end with the freedom of extension and contraction along the thickness direction of the sample 10; the clamping mechanism 4 is connected to the telescopic end of the compression mechanism 3, and the clamping mechanism 4 has the freedom of movement along the thickness direction of the sample 10 with the help of the compression mechanism 3; the electrode sheet 5 includes an upper electrode sheet 51 and a lower electrode sheet 52. The electrode piece 52 and the clamping mechanism 4 are used to clamp and fix the upper electrode piece 51 and the lower electrode piece 52, and with the help of the compression mechanism 3, the upper electrode piece 51 and the lower electrode piece 52 are respectively pressed against the side walls of the sample 10 at both ends, so that the electrode piece 5 provides a pulse current to the sample 10; the anti-buckling mechanism 6 is arranged between the upper chuck 1 and the lower chuck 2, and the anti-buckling mechanism 6 is suitable for slidingly clamping the sample 10 and preventing the sample 10 from buckling during the compression test; the centering clamping mechanism 7 is connected to the upper chuck 1 or the lower chuck 2, and the centering clamping mechanism 7 is suitable for clamping the anti-buckling mechanism 6 during the compression test and clamping the sample 10 during the tensile test, so that the sample 10 remains centered in its length direction.

[0081] The present invention provides a pulse current assisted tensile and compression self-centering test device. Compared with the prior art, the present invention enables a clamping fixture to clamp the sample 10, connect the clamping fixture to the testing machine and clamp the sample 10, and pull the clamping mechanism 4 to move through the compression mechanism 3, so that the clamping mechanism 4 can clamp and fix the electrode sheet 5, so that the electrode sheet 5 can provide a pulse current to the sample 10; when the sample is subjected to a compression test, the anti-buckling mechanism 6 slides against the sample 10 and prevents the sample 10 from buckling. The centering clamping mechanism 7 clamps the anti-buckling mechanism 6 and the sample 10 respectively during the compression and tensile tests, so that the length direction of the sample 10 can be kept centered, ensuring the safety and accuracy of the tensile and compression test processes, thereby promoting the widespread application of pulse current assisted tensile and compression test technology in material mechanical properties testing, and solving the technical problem that traditional test fixtures have limitations in testing pulse current assisted tensile and compression tests.

[0082] In this embodiment, the testing machine is a universal testing machine that can perform tensile and compression tests on the sample 10. The clamping fixture is installed on the upper chuck 1 and the lower chuck 2 to achieve clamping and fixing of the upper and lower ends of the sample 10. The compression mechanism 3 and the clamping mechanism 4 cooperate to ensure that the electrode sheet 5 is always in contact with the sample 10, ensuring that a pulse current can be provided during the test, and pulse current-assisted tensile and compression can be achieved. At the same time, by using the anti-buckling mechanism 6 and the centering clamping mechanism 7, the sample 10 can be self-centered during the compression test, effectively improving the experimental accuracy and preventing the occurrence of misalignment. Bolt holes 53 are provided on both the upper electrode sheet 51 and the lower electrode sheet 52. The cable is connected to the electrode sheet 5 through the bolt hole 53 to form a pulse current loop. By changing the parameters of the pulse power supply, such as the current, pulse frequency and duty cycle, the influence of different current characteristics on the electroplastic effect of the material can be evaluated.

[0083] In some embodiments, see Figures 1 to 5 The clamping fixture includes an upper clamping fixture 8 and a lower clamping fixture 9. The upper clamping fixture 8 is connected to the upper chuck 1 and is suitable for clamping and fixing one end of the sample 10. The clamping force of the upper clamping fixture 8 on the sample 10 can be adjusted. The lower clamping fixture 9 is connected to the lower chuck 2 and is suitable for clamping and fixing the other end of the sample 10. The clamping force of the lower clamping fixture 9 on the sample 10 can be adjusted. The upper clamping fixture 8 and the lower clamping fixture 9 are arranged in a vertically aligned manner. Grooves are provided at the bottom of the upper chuck 1 and the top of the lower chuck 2. The upper clamping fixture 8 and the lower clamping fixture 9 are respectively arranged in the two grooves. They are connected to the upper chuck 1 or the lower chuck 2 by power. By providing power to the upper chuck 1 and the lower chuck 2, the upper clamping fixture 8 and the lower clamping fixture 9 can clamp and fix the sample 10. By providing different degrees of power, the clamping force of the sample 10 can be adjusted.

[0084] In some embodiments, see Figures 1 to 5The upper clamping fixture 8 includes an upper left fixed clamp body 81 and an upper right fixed clamp body 82 which are fixedly connected to the upper clamp head 1 and are spaced apart. The upper left fixed clamp body 81 is connected to an upper left movable clamp body 83 on one side close to the upper right fixed clamp body 82, and the upper right fixed clamp body 82 is connected to an upper right movable clamp body 84 on one side close to the upper left fixed clamp body 81. A clamping space for the sample 10 is formed between the upper left movable clamp body 83 and the upper right movable clamp body 84. The lower clamping fixture 9 includes a lower left fixed clamp body 91 and a lower right fixed clamp body 92 which are fixedly connected to the lower clamp head 2 and are spaced apart. The lower left fixed clamp body 91 is connected to a lower left movable clamp body 93 on one side close to the lower right fixed clamp body 92, and the lower right fixed clamp body 92 is connected to a lower right movable clamp body 94 on one side close to the lower left fixed clamp body 91. A clamping space for the sample 10 is formed between the lower left movable clamp body 93 and the lower right movable clamp body 94. The upper left fixed clamp 81 and the upper right fixed clamp 82 are symmetrically arranged, and the lower left fixed clamp 91 and the lower right fixed clamp 92 are symmetrically arranged. The upper left movable clamp 83 and the upper right movable clamp 84 are approximately symmetrically arranged, and their structures are slightly different. The lower left movable clamp 93 and the lower right movable clamp 94 are approximately symmetrically arranged, and their structures are slightly different. The above-mentioned fixed clamps are in a fixed state, and the movable clamps are in a movable state. They are dynamically connected to the upper chuck 1 or the lower chuck 2. By providing different degrees of power, the degree or force of the clamping between the above-mentioned movable clamps can be controlled, so that the sample 10 can be clamped and fixed.

[0085] In some embodiments, see Figures 1 to 6 The compression mechanism 3 includes an upper external compression mechanism 31, an upper internal compression mechanism 32, a lower external compression mechanism 33 and a lower internal compression mechanism (not shown in the figure), the upper external compression mechanism 31 is connected to the clamping fixture and is close to the upper chuck 1; the upper internal compression mechanism 32 is connected to the clamping fixture and is close to the upper chuck 1, and is arranged in parallel with the upper external compression mechanism 31 in the horizontal direction; the lower external compression mechanism 33 is connected to the clamping fixture and is close to the lower chuck 2; the lower internal compression mechanism is connected to the clamping fixture and is close to the lower chuck 2, and is arranged in parallel with the lower external compression mechanism 33 in the horizontal direction; the upper external compression mechanism 31, the upper internal compression mechanism 32, the lower external compression mechanism 33 and the lower internal compression mechanism all have a telescopic end with a degree of freedom of telescopic extension along the thickness direction of the sample 10, and the telescopic end is arranged close to the sample 10; wherein, the upper external compression mechanism 31 and the upper internal compression mechanism 32 are used to telescope toward one end of the sample 10, and the lower external compression mechanism 33 and the lower internal compression mechanism are used to telescope toward the other end of the sample 10. The upper external compression mechanism 31 and the upper internal compression mechanism 32 are a group and are arranged at intervals, and are arranged at the upper chuck 1, located on one side of the sample 10; the lower external compression mechanism 33 and the lower internal compression mechanism are a group and are arranged at intervals, and are arranged at the lower chuck 2, located on one side of the sample 10, and are located on the same side of the sample 10 as the upper external compression mechanism 31.

[0086] Specifically, a space for accommodating the upper external compression mechanism 31 and the upper internal compression mechanism 32 is provided on the upper left movable clamp 83, and a space for accommodating the lower external compression mechanism 33 and the lower internal compression mechanism is provided on the lower left movable clamp 93 without affecting the clamping and fixing of the sample 10.

[0087] In some embodiments, see Figures 1 to 6 The upper outer compression mechanism 31, the upper inner compression mechanism 32, the lower outer compression mechanism 33, and the lower inner compression mechanism each include a compression base 311, a telescopic shaft 312, a compression spring 313, and a bolt 314. The inner side of the compression base 311 has a cavity; the telescopic shaft 312 is located in the cavity and is slidably connected to one side of the compression base 311. The telescopic shaft 312 has the freedom to move along its axial direction; the compression spring 313 is sleeved on the outer side of the telescopic shaft 312 and is used to pull the telescopic shaft 312 along its axial direction toward the inner side of the compression base 311; the bolt 314 is connected to the compression base 311 and is used to limit one end of the compression spring 313. With the help of the elastic force of the compression spring 313, the telescopic shaft 312 can provide a driving force that always keeps the electrode sheet 5 against the wall of the sample 10. In this way, the current on the electrode sheet 5 can be transmitted to the sample 10, wherein the clamping mechanism 4 is made of insulating material to prevent current conduction. One end of the telescopic shaft 312 extends out of the compression base 311, while the other end resides within the compression base 311. A compression spring 313 provides a retractive force, causing the outer end of the telescopic shaft 312 (the end located outside the compression base 311) to be constantly pulled toward the interior of the compression base 311, thereby forcing the electrode sheet 5 against the surface of the specimen 10. Specifically, a bolt 314 is disposed within the compression base 311, distal from the clamping mechanism 4. One end of the compression spring 313 abuts against the bolt 314, while the other end is connected to the telescopic shaft 312, thereby pulling the telescopic shaft 312 to move. The telescopic end of the compression mechanism 3 is the outer end of the telescopic column.

[0088] In some embodiments, see Figures 1 to 6The clamping mechanism 4 includes a screw slide base 41 and a screw chuck 42. One end of the screw slide base 41 is connected to the end of the telescopic shaft 312 extending out of the compression base 311. The screw slide base 41 has the freedom of axial movement along the telescopic shaft 312 with the help of the telescopic shaft 312; the screw chuck 42 is connected to the screw slide base 41. The screw chuck 42 is suitable for clamping and fixing the upper electrode sheet 51 or the lower electrode sheet 52. The screw chuck 42 moves with the help of the telescopic shaft 312 to make the upper electrode sheet 51 or the lower electrode sheet 52 stick to the side wall of the sample 10. The screw rail base 41 is a conventional technology, including a base body provided with a slide rail, a screw threadedly connected to the base body, and a screw chuck 42 including a screw nut, a fixed chuck, and a movable chuck. The fixed chuck is fixedly connected to one side of the upper end of the base body, the screw nut is threadedly connected to the screw, and the screw nut is also slidably connected to the slide rail. By rotating the screw, the screw nut slides on the slide rail, and the movable chuck is connected to the screw nut. The movable chuck moves simultaneously with the screw nut, and the distance between the movable chuck and the fixed chuck can be adjusted, thereby adjusting the clamping and fixation of electrode sheets 5 of different thicknesses. The screw rail base 41 can be pulled by the compression spring 313, so that the electrode sheet 5 always moves in the direction close to the sample 10, and then closely adheres to the sample 10.

[0089] In some embodiments, see Figure 1 、 Figures 7 to 11 The anti-buckling mechanism 6 includes an anti-buckling plate 61, a wear-resistant smooth insulating plate 62, a centering assembly 63, a connecting bolt 64 and a support spring 65. The anti-buckling plates 61 are in two groups and are respectively arranged on both sides of the sample 10; the wear-resistant smooth insulating plates 62 are in two groups and are respectively arranged on both sides of the sample 10. The two groups of wear-resistant smooth insulating plates 62 are located on the inner sides of the two groups of anti-buckling plates 61. The wear-resistant smooth insulating plates 62 are used to slide against the sample 10; the centering assembly 63 is connected to one side of the sample 10 and Located between the wear-resistant smooth insulating plates 62 and the anti-buckling plates 61, the centering assembly 63 is adapted to clamp the wear-resistant smooth insulating plates 62 and the specimen 10. Multiple connecting bolts 64 are provided, locking and securing the two sets of anti-buckling plates 61. The two sets of wear-resistant smooth insulating plates 62 and the centering assembly 63 are clamped and secured. Multiple support springs 65 are respectively sleeved onto the outer sides of the multiple connecting bolts 64. The support springs 65 are used to elastically push against the anti-buckling plates 61 and lock the two sets of anti-buckling plates 61. The two sets of wear-resistant smooth insulating plates 62 clamp the specimen 10, allowing the specimen 10 to slide between them. The two sets of anti-buckling plates 61 are connected and secured by the connecting bolts 64, securing the two sets of wear-resistant smooth insulating plates 62 and the centering assembly 63. This prevents buckling deformation of the specimen 10 during the compression test and maintains the specimen 10's centering.

[0090] Specifically, grooves are provided on the inner side surfaces of the two sets of anti-buckling plates 61, and the wear-resistant smooth insulating plates 62 and the centering assembly 63 can be snapped into the grooves. A perspective window 66 is aligned in the middle of the anti-buckling plate 61 and the middle of the wear-resistant smooth insulating plate 62. The sample 10 can be seen through the perspective window 66, thereby facilitating the observation of changes in the sample 10 (which can be measured in combination with a DIC device).

[0091] In some embodiments, see Figures 8 to 11 The centering component 63 includes a first tooth comb-shaped clamping guide plate 631, a second tooth comb-shaped clamping guide plate 632 and a centering spring 633. One side of the first tooth comb-shaped clamping guide plate 631 is set to a tooth comb-shaped structure, and one side of the second tooth comb-shaped clamping guide plate 632 is also set to a tooth comb-shaped structure. The two groups of tooth comb-shaped structures are plugged into each other, and the second tooth comb-shaped clamping guide plate 632 and the first tooth comb-shaped clamping guide plate 631 form a sliding plug-in. A space suitable for clamping the wear-resistant and smooth insulating plate 62 is formed between the second tooth comb-shaped clamping guide plate 632 and the first tooth comb-shaped clamping guide plate 631; the two ends of the centering spring 633 are respectively connected to the first tooth comb-shaped clamping guide plate 631 and the second tooth comb-shaped clamping guide plate 632. The centering spring 633 is used to pull the first tooth comb-shaped clamping guide plate 631 and the second tooth comb-shaped clamping guide plate 632 toward each other, thereby adjusting the width of the space. The wear-resistant smooth insulating plate 62 can be clamped and fixed by the elastic pulling force of the centering spring 633 .

[0092] In some embodiments, see Figures 12 to 13 The centering clamping mechanism 7 includes a base 71, a first guide rod 72, a second guide rod 73 and a two-way bolt clamping centering assembly 74. The base 71 is connected to the upper chuck 1 or the lower chuck 2; one end of the first guide rod 72 is hinged to the base 71, and the first guide rod 72 has the freedom of rotation around its hinged end; one end of the second guide rod 73 is rotatably connected to the other end of the first guide rod 72, and the second guide rod 73 has the freedom of rotation around its rotating end; the two-way screw clamping centering assembly 74 is connected to the other end of the second guide rod 73, and the two-way screw clamping centering assembly 74 is suitable for clamping the anti-buckling mechanism 6 during the compression test and clamping the specimen during the tensile test, so that the specimen 10 remains centered in its length direction. By screwing the bidirectional screw clamping centering assembly 74, the specimen 10 and the anti-buckling mechanism 6 can be clamped, which is used for tensile testing and compression testing of the specimen 10 respectively. Since the specimen 10 can be kept centered only by the bidirectional screw clamping centering assembly 74 during tension, and the specimen 10 itself will deform during the compression test, it is necessary to use the anti-buckling mechanism 6 and make the bidirectional screw clamping centering assembly 74 clamp the anti-buckling mechanism 6, so that the centering setting of the specimen 10 can be maintained.

[0093] In some embodiments, see Figures 12 to 13The bidirectional screw clamping centering assembly 74 includes a left clamp 741, a right clamp 742 and a bidirectional screw 743. One side of the right clamp 742 ( Figure 12 The bottom of the middle) and the end of the second guide rod 73 ( Figure 12 The right clamp 742 is hinged to the left clamp 741 at one end close to the left clamp 741, and a clamping space suitable for clamping and fixing the anti-buckling mechanism 6 is formed between the left clamp 741 and the right clamp 742; the bidirectional screw 743 passes through and is screwed to the left clamp 741 and the right clamp 742 at the same time, and the bidirectional screw 743 is used to adjust the width of the clamping space between the left clamp 741 and the right clamp 742. The left clamp 741 and the right clamp 742 both have screw holes aligned with each other, and the bidirectional screw 743 passes through the two screw holes and extends from the outside of the left clamp 741. The left clamp 741 and the right clamp 742 are approximately symmetrical structures, similar to the structure of a clamp, with one end of the two forming a hinge and the other end forming a clamping space for contacting and clamping the anti-buckling mechanism 6 or the specimen 10 ( Figure 12-13 (The expansion or clamping action is performed in the horizontal direction).

[0094] Specifically, the bidirectional screw 743 has two parts of external threads with different spiral directions, which are respectively threadedly connected to the left clamp 741 and the right clamp 742. By screwing one end of the bidirectional screw 743, the left clamp 741 and the right clamp 742 can be rotated at the same time, thereby expanding or reducing the clamping space, which is beneficial to the clamping and fixation of the anti-buckling mechanism 6, so that the sample 10 remains in a centered state.

[0095] The process and embodiment of the tensile test of the present invention are as follows: the upper clamping fixture 8 is fixed to the upper chuck 1 of the universal testing machine, and the lower clamping fixture 9 is fixed to the lower chuck 2 of the universal testing machine; the upper electrode sheet 51 is installed to the upper clamping mechanism 4 and fixed by using the inner and outer clamping mechanisms 4; the lower electrode sheet 52 is installed to the lower clamping mechanism 4 and also fixed by using the inner and outer clamping mechanisms 4; the sample 10 is placed in the upper chuck 1 and the lower chuck 2 of the testing machine; the sample 10 is fixed by the centering clamping mechanism 7 (the anti-buckling mechanism 6 is not used when the tensile test is performed on the sample 10, and only the centering clamp is used). The tightening mechanism 7 is used to clamp the sample 10 to achieve its self-centering; the upper electrode sheet 51 is pulled outward, and the upper end of the sample 10 is clamped by the compressive force of the upper two compression mechanisms 3, and the lower electrode sheet 52 is pulled outward, and the lower end of the sample 10 is clamped by the compressive force of the lower two compression mechanisms 3; the anti-buckling mechanism 6 is not installed; the current switching and self-centering of the test piece during the stretching process are achieved through the above steps; the upper chuck 1 and the lower chuck 2 of the testing machine are clamped to achieve the installation of the sample 10; the stretching is started, and the DIC equipment is used to measure on the front of the sample to obtain the tensile test data assisted by the pulse current.

[0096] The process and embodiment of the compression test of the present invention are as follows: the upper clamping fixture 8 is fixed to the upper chuck 1 of the universal testing machine, and the lower clamping fixture 9 is fixed to the lower chuck 2 of the universal testing machine; the upper electrode sheet 51 is installed to the upper clamping mechanism 4 and fixed by the inner and outer clamping mechanisms 4; the lower electrode sheet 52 is installed to the lower clamping mechanism 4 and fixed by the inner and outer clamping mechanisms 4; the sample 10 is placed in the upper chuck 1 and the lower chuck 2 of the testing machine; the anti-buckling mechanism 6 is matched and installed with the sample 10, the centering component 63 of the anti-buckling mechanism 6 is pulled open, and the sample 10 is placed to achieve the centering position relationship between the sample 10 and the anti-buckling mechanism 6, and the sample 10 is clamped by the connecting bolt 64 and the support spring 65. The supporting strength of the support spring 65 and the tightening force of the connecting bolt 64 are adjusted according to the mechanical properties of the sample 10. The above steps complete the installation of the sample 10 and the anti-buckling mechanism 6, and realize the pre-clamping of the sample 10 and the centering relative to the anti-buckling mechanism 6; the anti-buckling mechanism 6 of the sample 10 is clamped by the centering clamping mechanism 7 to realize the self-centering of the sample 10 installed with the anti-buckling mechanism 6; the upper electrode sheet 51 is pulled outward, and the upper end of the sample 10 is clamped by the compression force of the upper two compression mechanisms 3, and the lower electrode sheet 52 is pulled outward, and the lower end of the sample 10 is clamped by the compression force of the lower two compression mechanisms 3; the current on and off during the compression process, the self-centering of the test piece and the anti-buckling during the compression process are realized through the above steps; the upper chuck 1 and the lower chuck 2 of the testing machine are clamped to realize the installation of the sample 10; when compression starts, the DIC equipment can be used to measure the front and side of the sample 10, verify the data integrity, and obtain the compression test data assisted by pulse current.

[0097] The present invention can meet the process requirements of multiple types and specifications of specimens 10, can simultaneously realize pulse current assisted tensile testing and pulse current assisted compression testing, and can ensure the self-centering of the specimen 10 with respect to the testing machine. The experimental results are highly accurate, and the consistency of the power-on environment can be ensured. The operation is convenient and the test versatility is strong.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pulse current assisted tensile and compression self-centering test device, characterized in that: include: A testing machine having an upper chuck and a lower chuck; A clamping fixture connected to the upper clamp and the lower clamp, the clamping fixture being suitable for clamping and fixing both ends of the sample; a compression mechanism connected to the clamping fixture, the compression mechanism having a telescopic end with a degree of freedom of extension and contraction along the thickness direction of the specimen; a clamping mechanism connected to the telescopic end of the compression mechanism, wherein the clamping mechanism has the freedom to move along the thickness direction of the sample by means of the compression mechanism; The electrode sheet includes an upper electrode sheet and a lower electrode sheet, wherein the clamping mechanism is used to clamp and fix the upper electrode sheet and the lower electrode sheet, and the compression mechanism is used to make the upper electrode sheet and the lower electrode sheet respectively stick to the side walls of the sample, so that the electrode sheet provides a pulse current to the sample; an anti-buckling mechanism, disposed between the upper chuck and the lower chuck, the anti-buckling mechanism being adapted to slidably clamp the specimen and prevent the specimen from buckling during a compression test; A centering clamping mechanism is connected to the upper clamp or the lower clamp, and is suitable for clamping the anti-buckling mechanism during a compression test and clamping the sample during a tensile test, so that the sample is centered in its length direction.

2. A pulse current assisted tensile and compression self-centering test device according to claim 1, characterized in that: The clamping fixture comprises: an upper clamping fixture connected to the upper chuck and adapted to clamp and fix one end of the sample, wherein the clamping force of the upper clamping fixture on the sample is adjustable; The lower clamping fixture is connected to the lower clamping head and is suitable for clamping and fixing the other end of the sample. The clamping force of the lower clamping fixture on the sample can be adjusted.

3. A pulse current assisted tensile and compression self-centering test device as claimed in claim 2, characterized in that: The upper clamping fixture includes an upper left fixed clamp body and an upper right fixed clamp body fixedly connected to the upper clamp head and spaced apart, the upper left fixed clamp body is connected to an upper left movable clamp body on one side close to the upper right fixed clamp body, and the upper right fixed clamp body is connected to an upper right movable clamp body on one side close to the upper left fixed clamp body, and a clamping space for the specimen is formed between the upper left movable clamp body and the upper right movable clamp body; The lower clamping fixture includes a lower left fixed clamp body and a lower right fixed clamp body which are fixedly connected to the lower clamp head and are spaced apart. The lower left fixed clamp body is connected to a lower left movable clamp body on one side close to the lower right fixed clamp body, and the lower right fixed clamp body is connected to a lower right movable clamp body on one side close to the lower left fixed clamp body. A clamping space for the sample is formed between the lower left movable clamp body and the lower right movable clamp body.

4. The pulse current assisted tensile and compression self-centering test device according to claim 1, characterized in that: The compression mechanism comprises: an upper external compression mechanism connected to the clamping fixture and proximate to the upper chuck; an upper inner compression mechanism connected to the clamping fixture and close to the upper clamping head, and arranged in parallel with the upper outer compression mechanism in the horizontal direction; a lower external compression mechanism connected to the clamping fixture and proximate to the lower clamp; a lower inner compression mechanism connected to the clamping fixture and close to the lower chuck, and arranged in parallel with the lower outer compression mechanism in the horizontal direction; the upper outer compression mechanism, the upper inner compression mechanism, the lower outer compression mechanism and the lower inner compression mechanism all have a telescopic end with a degree of freedom of extension and contraction along the thickness direction of the sample, and the telescopic end is arranged close to the sample; The upper outer compression mechanism and the upper inner compression mechanism are used to extend and retract toward one end of the sample, and the lower outer compression mechanism and the lower inner compression mechanism are used to extend and retract toward the other end of the sample.

5. A pulse current assisted tensile and compression self-centering test device as claimed in claim 4, characterized in that: The upper outer compression mechanism, the upper inner compression mechanism, the lower outer compression mechanism and the lower inner compression mechanism all include: A compression base with a cavity inside; A telescopic shaft is located in the cavity and is slidably plugged into one side of the compression base, and the telescopic shaft has freedom of movement along its axial direction; A compression spring is sleeved on the outside of the telescopic shaft, and the compression spring is used to pull the telescopic shaft to move along its axial direction toward the inner side of the compression base; A bolt is connected to the compression base, and the bolt is used to limit one end of the compression spring.

6. A pulse current assisted tensile and compression self-centering test device according to claim 5, characterized in that: The clamping mechanism comprises: A screw rail base, one end of which is connected to an end of the telescopic shaft extending out of the compression base, and the screw rail base has the freedom to move axially along the telescopic shaft by means of the telescopic shaft; A lead screw chuck is connected to the lead screw slide base, and the lead screw chuck is suitable for clamping and fixing the upper electrode sheet or the lower electrode sheet. The lead screw chuck moves with the help of the telescopic shaft to make the upper electrode sheet or the lower electrode sheet stick to the side wall of the sample.

7. The pulse current assisted tensile and compression self-centering test device according to claim 1, characterized in that: The anti-buckling mechanism comprises: Buckling restraint plates, in two groups, are installed on both sides of the specimen; Two groups of wear-resistant smooth insulating plates are provided on both sides of the specimen, the two groups of wear-resistant smooth insulating plates are located inside the two groups of anti-buckling plates, and the wear-resistant smooth insulating plates are used to slide against the specimen; a centering assembly connected to one side of the specimen and located between the wear-resistant smooth insulating plate and the anti-buckling plate, wherein the centering assembly is suitable for clamping the wear-resistant smooth insulating plate and the specimen; There are multiple connecting bolts used to lock and fix the two sets of anti-buckling plates, the two sets of wear-resistant smooth insulating plates, and the centering assembly; There are multiple support springs that are respectively sleeved on the outside of the multiple connecting bolts. The support springs are used to elastically push the anti-buckling plates and lock the two groups of anti-buckling plates.

8. The pulse current assisted tensile and compression self-centering test device according to claim 7, characterized in that: The centering assembly comprises: a first tooth comb-shaped clamping guide plate; A second tooth-comb-shaped clamping guide plate is slidably connected to the first tooth-comb-shaped clamping guide plate, and a space suitable for clamping the wear-resistant smooth insulating plate is formed between the second tooth-comb-shaped clamping guide plate and the first tooth-comb-shaped clamping guide plate; A centering spring, both ends of which are respectively connected to the first tooth comb-shaped clamping guide plate and the second tooth comb-shaped clamping guide plate. The centering spring is used to pull the first tooth comb-shaped clamping guide plate and the second tooth comb-shaped clamping guide plate toward each other, thereby adjusting the space width.

9. The pulse current assisted tensile and compression self-centering test device according to claim 1, characterized in that: The centering clamping mechanism comprises: A base, connected to the upper chuck or the lower chuck; a first guide rod, one end of which is hinged to the base, the first guide rod having a degree of freedom of rotation about its hinged end; a second guide rod, one end of which is rotatably connected to the other end of the first guide rod, the second guide rod having a degree of freedom of rotation about its rotation end; A bidirectional screw clamping and centering assembly is connected to the other end of the second guide rod. The bidirectional screw clamping and centering assembly is suitable for clamping the anti-buckling mechanism during a compression test and clamping the sample during a tensile test so that the sample is centered in its length direction.

10. The pulse current assisted tension and compression self-centering test device according to claim 9, characterized in that: The bidirectional screw clamping and centering assembly includes: a right clamp, one side of which is connected to the end of the second guide rod; A left clamp, one end of which is hinged to the right clamp, and a clamping space suitable for clamping and fixing the anti-buckling mechanism is formed between the left clamp and the right clamp; A bidirectional screw passes through and is simultaneously screwed to the left clamp and the right clamp, and the bidirectional screw is used to adjust the width of the clamping space between the left clamp and the right clamp.

Images