Clamping mechanism for pulse current assisted uniaxial tensile test

Abstract

The utility model relates to a clamping mechanism for a pulse current auxiliary uniaxial tensile test, which comprises an upper insulation clamping block and a lower insulation clamping block, the upper insulation clamping block is composed of two unit blocks, the opposite surfaces of the two unit blocks are both provided with trapezoidal grooves, a first clamping conductive piece and a second clamping conductive piece are respectively inserted in the trapezoidal grooves, and the first clamping conductive piece and the second clamping conductive piece are arranged in the lower insulation clamping block. The lower insulating block and the upper insulating block are symmetrically arranged and have the same structure, a tensile sample is clamped between the first clamping conductive part and the second clamping conductive part of the upper insulating block and the lower insulating block, and the end part of the first clamping conductive part is connected to a pulse current machine through a wire. Through the separated design, the tensile sample can be stably and firmly clamped, meanwhile, the clamping conductive piece is convenient to mount, dismount and replace, the use requirements of rod-shaped and plate-shaped samples can be met, and the application range is wide.

Description

Technical Field

[0001] This utility model belongs to the field of metal material deformation behavior testing technology, specifically relating to a clamping mechanism for pulse current assisted uniaxial tensile testing. Background Technology

[0002] Pulsed current-assisted stretching is a novel processing method that improves the plastic deformation capacity of metallic materials by applying high-density pulsed current. Its core principle is based on the electroplastic effect. This effect was first discovered by scientists VISpitsyn and OATroitskii in the 1960s during tensile experiments on zinc single crystals. Experiments showed that under the influence of current, the flow stress of the material was significantly reduced, and the elongation was significantly increased. This discovery opened up a new research direction in the field of metal plastic processing. With further research, the unique advantages of pulsed current have become increasingly apparent: it can not only reduce the deformation resistance of materials but also inhibit work hardening, reduce crack initiation, and improve the uniformity of the material's microstructure. Therefore, it shows broad application prospects in aerospace, new energy vehicles, and high-end equipment manufacturing. However, pulsed current-assisted tensile testing technology still has significant room for development. For example, Chinese patent CN201711225627 discloses a testing device for uniaxial tensile testing of a rod-shaped specimen assisted by pulsed current. This tensile testing machine includes tensile clamps fixedly connected to both ends of the rod-shaped specimen and a driving device for moving the clamps closer or further apart. Conductive rings connected to the positive and negative terminals of a pulsed power supply are provided at both ends of the rod-shaped specimen. The tensile clamps have wedge-shaped cavities, and each cavity contains two opposing insulating blocks. Slots are provided on the opposing surfaces of the two insulating blocks, and positioning blocks are located in each slot. Positioning grooves for accommodating the ends of the rod-shaped specimen and the conductive rings are provided on the opposing surfaces of the two positioning blocks. This invention has a complex structure, can only be used for tensile testing of rods, and requires specific treatment of the tensile specimen according to the clamp structure, lacking versatility. In summary, pulsed current significantly improves the processing performance and machinability of materials, but the following problems still exist in existing experimental research:

[0003] 1. Most existing pulse current assisted tensile testing devices are designed for rod-shaped or plate-shaped workpieces and are not universal. During the test, a complete set of corresponding fixtures needs to be replaced, which is cumbersome and costly.

[0004] 2. Most existing pulse current assisted tensile testing devices are one-piece structures. If the clamping surface is damaged during use, the entire set of clamps must be replaced, which causes a certain waste of natural resources.

[0005] 3. Existing pulse current assisted tensile testing devices have relatively complex structures due to considerations of insulation measures and power supply methods, resulting in cumbersome installation and use processes;

[0006] 4. Most existing pulse current assisted tensile testing devices require corresponding treatment of the tensile specimens, which increases the geometric dimensions and accuracy requirements of the tensile specimens.

[0007] Based on the problems encountered in the design of existing pulse current assisted tensile test insulation and energized clamps during practical use, it is necessary to develop a new clamping mechanism for pulse current assisted uniaxial tensile test. Utility Model Content

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a clamping mechanism for pulse current assisted uniaxial tensile testing.

[0009] The technical problem solved by this utility model is achieved through the following technical solution:

[0010] A clamping mechanism for pulse current-assisted uniaxial tensile testing includes an upper insulating clamp and a lower insulating clamp, which are respectively installed at both ends of a tensile testing machine. The upper insulating clamp consists of two unit blocks, each with a trapezoidal groove on its opposite surface. A first clamping conductive element and a second clamping conductive element are respectively inserted into the trapezoidal groove. The lower insulating block is symmetrically arranged with the upper insulating block and has the same structure. A tensile specimen is clamped between the first and second clamping conductive elements of the upper and lower insulating blocks. The end of the first clamping conductive element is connected to the pulse current machine via a wire.

[0011] Furthermore, the outer surface of the unit block of the upper insulating clamp is an inclined surface that slopes inward from top to bottom, and the outer surface of the unit block of the lower insulating clamp is an inclined surface that slopes inward from bottom to top. The two unit blocks of the upper insulating clamp form a trapezoidal structure, and the two unit blocks of the lower insulating block form a trapezoidal structure.

[0012] Furthermore, the inner side of the trapezoidal groove is a trapezoidal base.

[0013] Moreover, both the first and second clamping conductive elements are trapezoidal structures, and the contact surface with the upper insulating block or the upper insulating block is the bottom surface of the trapezoid.

[0014] Moreover, the trapezoidal groove is located in the middle of the upper insulating block or the lower insulating block and does not penetrate the upper insulating block or the lower insulating block.

[0015] Furthermore, the end of the unit block of the upper insulating clamp or the lower insulating clamp is integrally provided with a C-shaped groove, and the outer side of the C-shaped groove is provided with a chamfer.

[0016] Furthermore, the first and second clamping conductive elements are plate-shaped or rod-shaped clamping conductive elements, with the plate-shaped clamping conductive elements clamping the plate-shaped tensile specimen between them; the opposite surfaces of the rod-shaped clamping conductive elements are provided with V-shaped grooves, and the rod-shaped tensile specimen is clamped in the V-shaped grooves.

[0017] Furthermore, anti-slip knurling is provided on the opposing surfaces of the first and second clamping conductive components.

[0018] Furthermore, the V-shaped slot is provided with anti-slip texture.

[0019] Furthermore, both the upper and lower insulating clamps are made of high-strength insulating material polyetheretherketone, and both the first and second clamping conductive components are made of aluminum bronze.

[0020] The advantages and beneficial effects of this utility model are as follows:

[0021] 1. The clamping mechanism of this utility model includes an upper insulating clamping block and a lower insulating clamping block. The upper insulating clamping block is composed of two unit blocks. Each of the two unit blocks has a trapezoidal groove on its opposite surface. A first clamping conductive element and a second clamping conductive element are respectively inserted into the trapezoidal groove. The lower insulating block is symmetrically arranged with the upper insulating block and has the same structure. A tensile specimen is clamped between the first clamping conductive element and the second clamping conductive element of the upper insulating block and the lower insulating block. The separate design can not only achieve stable and firm clamping of the tensile specimen, but also facilitate the installation, disassembly and replacement of the clamping conductive elements. It can meet the usage requirements of rod-shaped and plate-shaped specimens and has a wide range of applications.

[0022] 2. The outer side of the unit block of the upper insulating clamping block of this utility model is an inclined surface that slopes inward from top to bottom, and the outer side of the unit block of the lower insulating clamping block is an inclined surface that slopes inward from bottom to top. The two unit blocks of the upper insulating clamping block form a trapezoidal structure, and the two unit blocks of the lower insulating block form a trapezoidal structure, which saves space and facilitates its installation and placement on the tensile testing machine.

[0023] 3. The inner side of the trapezoidal groove of the clamping mechanism of this utility model is a trapezoidal bottom surface, which better ensures the structural strength of the insulating clamp and avoids the possibility of the lower part of the insulating clamp falling off due to the upper and lower tensile forces during the stretching process.

[0024] 4. The first and second clamping conductive components of the clamping mechanism of this utility model are both trapezoidal structures, and the contact surface with the upper insulating block or the upper insulating block is the bottom surface of the trapezoid, which increases the contact area between the two. The wide contact surface at the bottom disperses the pressure, reduces the local stress peak at the interface between the two, and reduces the risk of brittle fracture of the insulating block. The matching design of the trapezoidal inclined surface and the insulating block forms a "wedge effect", which generates a self-locking effect when subjected to force, further improving the interface bonding force.

[0025] 5. The trapezoidal groove of the clamping mechanism of this utility model is located in the middle of the upper insulating block or the lower insulating block and does not penetrate the upper insulating block or the lower insulating block, thereby improving the insulation effect.

[0026] 6. The clamping mechanism of this utility model has a C-shaped groove integrally formed at the end of the unit block of the upper or lower insulating clamping block, and the outer side of the C-shaped groove is chamfered, which facilitates tight connection with the tensile testing machine, reduces material consumption, and improves operational safety.

[0027] 7. The clamping mechanism of this utility model has a first clamping conductive element and a second clamping conductive element, which are plate-shaped clamping conductive elements or rod-shaped clamping conductive elements. The plate-shaped clamping conductive elements clamp a plate-shaped tensile specimen between them. The opposite surfaces of the rod-shaped clamping conductive elements are provided with V-shaped grooves, and the rod-shaped tensile specimen is clamped in the V-shaped grooves. The clamping conductive elements can be disassembled and replaced at any time according to the needs of different specimens. The operation is convenient and the application range is wide.

[0028] 8. The clamping mechanism of this utility model has anti-slip knurling on the opposite surfaces of the first clamping conductive component and the second clamping conductive component, and anti-slip texture is provided in the V-shaped groove to ensure stable and firm clamping of the tensile specimen.

[0029] 9. The upper and lower insulating clamping blocks of the clamping mechanism of this utility model are both made of high-strength insulating material polyetheretherketone, and the first and second clamping conductive parts are both made of aluminum bronze, which can effectively prevent the influence of pulse current on the upper and lower insulating clamping blocks and improve the test accuracy of tensile test. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of this utility model;

[0031] Figure 2 This is a schematic diagram of the upper insulating clamping block used in the tensile test of the sheet metal according to this utility model.

[0032] Figure 3 This is a schematic diagram of the upper insulating clamping block used in the bar tensile test of this utility model;

[0033] Figure 4 This is a schematic diagram of the structure of the insulating clamp and the rod-shaped conductive clamp of this utility model.

[0034] Explanation of reference numerals in the attached figures

[0035] 1-Upper insulating clamp, 2-Wire, 3-First clamping conductive component, 4-Second clamping conductive component, 5-Lower insulating clamp, 6-Unit block, 7-Anti-slip knurling, 8-Chamfer, 9-C-groove, 10-Anti-slip texture, 11-V-groove, 12-Trapezoidal groove. Detailed Implementation

[0036] The present invention will be further described in detail below through specific embodiments. The following embodiments are only descriptive and not limiting, and should not be used to limit the protection scope of the present invention.

[0037] An innovative clamping mechanism for pulse current-assisted uniaxial tensile testing includes an upper insulating clamping block 1 and a lower insulating clamping block 5, which are respectively installed at both ends of a tensile testing machine. The upper insulating clamping block is composed of two unit blocks 6, and trapezoidal grooves 12 are provided on the opposite surfaces of the two unit blocks. A first clamping conductive element 3 and a second clamping conductive element 4 are respectively inserted into the trapezoidal grooves. The lower insulating block is symmetrically arranged with the upper insulating block and has the same structure. The tensile specimen is clamped between the first clamping conductive element and the second clamping conductive element of the upper and lower insulating blocks. The end of the first clamping conductive element is connected to the pulse current machine through a wire 2.

[0038] This invention, through its detachable design, not only achieves stable and secure clamping of tensile specimens, but also facilitates the installation, disassembly, and replacement of conductive components, meeting the needs of both rod-shaped and plate-shaped specimens and having a wide range of applications.

[0039] The outer surface of the unit block of the upper insulating clamp is an inclined surface that slopes inward from top to bottom, and the outer surface of the unit block of the lower insulating clamp is an inclined surface that slopes inward from bottom to top. The two unit blocks of the upper insulating clamp form a trapezoidal structure, and the two unit blocks of the lower insulating clamp form a trapezoidal structure, which saves space and facilitates its installation and placement on the tensile testing machine.

[0040] The inner side of the trapezoidal groove is a trapezoidal base, which better ensures the structural strength of the insulating clamp and avoids the possibility of the lower part of the insulating clamp falling off due to the tensile force during the stretching process.

[0041] Both the first and second clamping conductive components are trapezoidal structures, and their contact surfaces with the upper insulating block or the upper insulating block are trapezoidal base surfaces, which increases the contact area between the two. The wide contact surface at the bottom disperses the pressure, reduces the local stress peak at the interface between the two, and reduces the risk of brittle fracture of the insulating block. The matching design of the trapezoidal inclined surface and the insulating block forms a "wedge effect", which generates a self-locking effect when subjected to force, further enhancing the interface bonding force.

[0042] The trapezoidal groove is located in the middle of the upper or lower insulating block and does not penetrate through the upper or lower insulating block, thereby improving the insulation effect.

[0043] The end of the unit block of the upper or lower insulating clamp is integrally provided with a C-shaped groove 9, and the outer side of the C-shaped groove is provided with a chamfer 8, which facilitates a tight connection with the tensile testing machine, reduces material consumption, and improves operational safety.

[0044] The first and second clamping conductive components are plate-shaped or rod-shaped clamping conductive components, with a plate-shaped tensile specimen clamped between the plate-shaped clamping conductive components; V-shaped slots 11 are provided on the opposite surfaces of the rod-shaped clamping conductive components, and rod-shaped tensile specimens are clamped in the V-shaped slots. The clamping conductive components can be disassembled and replaced at any time according to the needs of different specimens, making operation convenient and applicable to a wide range of applications.

[0045] The first and second clamping conductive components are provided with anti-slip knurling 7 on their opposing surfaces, and anti-slip texture 10 is provided in the V-shaped groove to ensure stable and firm clamping of the tensile specimen.

[0046] Both the upper and lower insulating clamps are made of high-strength insulating material polyetheretherketone (PEEK), and the first and second clamping conductive components are made of aluminum bronze. This effectively prevents the influence of pulse current on the upper and lower insulating clamps and improves the test accuracy of the tensile test.

[0047] The working principle of this utility model is as follows:

[0048] When performing a tensile test on a sheet metal, the first and second clamping conductive components are inserted into the upper and lower insulating blocks, respectively, and the upper and lower insulating blocks are installed on the universal tensile testing machine. The sheet metal to be stretched is placed between the first and second clamping conductive components and clamped. The end of the first clamping conductive component is then connected to the pulse current generator via a wire. The pulse current generator is started to generate a pulse current and apply it to the sheet-shaped tensile specimen. At the same time, the tensile testing machine is started to perform axial stretching on the tensile specimen.

[0049] When conducting a bar tensile test, simply replace the first and second clamping conductive elements, and then place the bar specimen into the V-shaped groove on the opposite side of the first and second clamping conductive elements to perform the tensile test.

[0050] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A clamping mechanism for a pulsed current assisted uniaxial tensile test, characterized by: The upper and lower insulation clamping blocks are respectively installed at both ends of the tensile testing machine, the upper insulation clamping block is composed of two unit blocks, the opposite surfaces of the two unit blocks are respectively provided with trapezoidal grooves, the first and second clamping conductive parts are respectively inserted into the trapezoidal grooves, the lower insulation clamping block is symmetrically arranged with the upper insulation clamping block and has the same structure, the first and second clamping conductive parts of the upper and lower insulation clamping blocks clamp the tensile sample, and the end of the first clamping conductive part is connected to the pulse current machine through a wire.

2. The clamping mechanism for a pulse current-aided uniaxial tensile test according to claim 1, characterized by: The outer side surface of the unit block of the upper insulation clamping block is an inclined surface that inclines inward from top to bottom, the outer side surface of the unit block of the lower insulation clamping block is an inclined surface that inclines inward from bottom to top, the two unit blocks of the upper insulation clamping block form a trapezoidal structure, and the two unit blocks of the lower insulation clamping block form a trapezoidal structure.

3. The clamping mechanism for a pulse current-aided uniaxial tensile test according to claim 1, characterized by: The inner side surface of the trapezoidal groove is a trapezoidal bottom surface.

4. The clamping mechanism for a pulse current-aided uniaxial tensile test according to claim 1, characterized by: The first and second clamping conductive parts are trapezoidal structures, and the contact surfaces with the upper or lower insulation clamping block are trapezoidal bottom surfaces.

5. The clamping mechanism for a pulse current-aided uniaxial tensile test according to claim 1, characterized by: The trapezoidal groove is located in the middle of the upper or lower insulation clamping block and does not penetrate the upper or lower insulation clamping block.

6. The clamping mechanism for a pulse current- assisted uniaxial tensile test according to claim 1, characterized by: The end of the unit block of the upper or lower insulation clamping block is integrally provided with a C-shaped groove, and the outer side of the C-shaped groove is provided with a chamfer.

7. The clamping mechanism for a pulse current- assisted uniaxial tensile test according to claim 1, characterized by: The first and second clamping conductive parts are plate-shaped clamping conductive parts or rod-shaped clamping conductive parts, the plate-shaped clamping conductive parts clamp plate-shaped tensile samples therebetween, and the opposite surfaces of the rod-shaped clamping conductive parts are provided with V-shaped clamping grooves, and rod-shaped tensile samples are clamped in the V-shaped clamping grooves.

8. The clamping mechanism for a pulse current- assisted uniaxial tensile test according to claim 1, characterized by: The opposite surfaces of the first and second clamping conductive parts are provided with anti-slip knurls.

9. The clamping mechanism for a pulse current assisted uniaxial tensile test according to claim 7, characterized by: The V-shaped clamping groove is provided with an anti-slip pattern.

10. The clamping mechanism for a pulse current- assisted uniaxial tensile test according to claim 1, characterized by: The upper and lower insulation clamping blocks are made of high-strength insulation material polyether ether ketone, and the first and second clamping conductive parts are made of aluminum bronze.

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