A high-speed current-carrying strain experiment device

Abstract

The application discloses a high-speed current-carrying strain experiment device, which comprises a base, a protection tube and an electric wire. The protection tube is horizontally arranged on the top of the base and fixedly installed at both ends of the base. The electric wire is arranged in the protection tube and extends along the axis of the protection tube. The electric wire is insulated from the protection tube and the base. The arc part of a test piece is used for sleeving the outer circumferential surface of the axial middle part of the protection tube. Insulating pads are arranged between two long plates. The two long plates are provided with conductive blocks, insulating blocks and jacks in sequence on the side away from the insulating pads. The jacks are screw-connected with the base and used for pressing the long plates on the insulating pads. The bottom ends of the two conductive blocks are arranged outside the base and form wiring ends for connecting a power supply, so that the test piece can carry current when being impacted by a shock wave. The experiment device solves the problems that the upper limit of the strain rate that can be applied to the test piece by the current experiment device is low and the material cannot carry current under high strain rate.

Description

Technical Field

[0001] This invention relates to the field of experimental technology for the microstructure evolution of materials under current-carrying strain, and specifically to a high-speed current-carrying strain experimental device. Background Technology

[0002] The Hopkinson bar apparatus is commonly used to study the microstructure evolution of materials under dynamic loading conditions. The Hopkinson bar apparatus generates stress waves through the mechanical collision of an impact bar and an incident bar, causing the sample to deform at a certain strain rate. The evolution of the material's microstructure under dynamic loading conditions is then studied by characterizing the sample's microstructure. High-speed rail pantographs, electric motor brushes, and electromagnetic railguns all involve high-speed sliding electrical contact problems, where the material surface undergoes high strain rate strain under current-carrying conditions. In these cases, the Hopkinson bar apparatus exhibits two drawbacks:

[0003] 1. Because the Hopkinson bar test apparatus induces material deformation through stress waves generated by the mechanical collision between the impact bar and the incident bar, it can only produce a relatively low strain rate in the specimen, typically 10. 2 ~10 4 / s, which cannot meet the needs of studying the evolution of material microstructure under high-speed contact environments.

[0004] 2. The Hopkinson bar test apparatus cannot introduce current into the material specimen while applying strain, thus it cannot simultaneously study the microstructure evolution of the material under current-carrying and high strain rate conditions. Summary of the Invention

[0005] In view of this, the present invention provides a high-speed current-carrying strain experimental device. This experimental device uses electrical energy to generate shock waves through an electric wire to bombard the surface of the specimen, causing the material microstructure to produce high strain rate strain. At the same time, current is applied to the specimen, providing an experimental platform for studying the evolution of the microstructure of materials under high-speed sliding electrical contact environment. It solves the technical problems of the current experimental devices having a low upper limit of the strain rate that can be applied to the specimen and being unable to make the material carry current at high strain rate conditions.

[0006] The present invention adopts the following specific technical solution:

[0007] A high-speed current-carrying strain test apparatus, comprising a base, a protective tube, and an electric wire;

[0008] The base is provided with a cavity that is open at both the top and the bottom;

[0009] The protective tube spans the top of the base and is fixedly installed at both ends of the base for mounting the test specimen.

[0010] The electric wire is inserted inside the protective tube and extends along the axis of the protective tube. Both ends are used to connect to a power source so that the electric wire explodes and the shock wave generated by the explosion bombards the surface of the specimen evenly. The electric wire is insulated from the protective tube and the base.

[0011] The specimen includes an arc portion and two long strips connected side by side to both ends of the arc portion; the arc portion is used to fit onto the outer circumferential surface of the axial middle part of the protective tube; an insulating pad is sandwiched between the two long strips, and a conductive block, an insulating block and a set screw are sequentially arranged on the side of the two long strips away from the insulating pad;

[0012] The set screw is screwed into the base to press the long strip plate against the insulating pad through the insulating block and the conductive block;

[0013] The bottom ends of both conductive blocks extend out of the base and form terminals for connecting to a power source, so that the specimen carries current when bombarded by a shock wave.

[0014] Furthermore, it also includes insulating rings, plugs, and closing caps disposed at both ends of the protective tube;

[0015] The insulating ring is provided with an annular bushing, a flange fixedly connected to one end of the bushing, and a through hole that passes through the bushing and the flange along the axial direction.

[0016] The plug is provided with a small diameter end with the same inner diameter as the protective tube, a large diameter end with the same inner diameter as the through hole, and a central hole that extends axially.

[0017] The base has a top semi-circular groove with a top opening and a threaded hole at the top.

[0018] The closed cover is provided with a bottom semicircular groove that corresponds one-to-one with the top semicircular groove and has an opening at the bottom;

[0019] The closing cover is mounted on top of the base by a screw that is threaded into the threaded hole;

[0020] The small-diameter end of the plug is inserted into the protective tube, and the large-diameter end is fitted into the through hole of the insulating ring.

[0021] The end of the wire passes through the central hole of the plug, is bent, and fixed to the outer end face of the large-diameter end of the plug;

[0022] The bushing is housed within the corresponding bottom semicircular groove and the top semicircular groove, and is pressed against the base by the closing cover.

[0023] Furthermore, the end of the electric wire is fixed to the outer end face of the large-diameter end of the plug by copper foil.

[0024] Furthermore, the central hole of the plug is composed of a fine hole located in the small diameter end, a coarse hole located in the large diameter end, and a tapered hole connecting the fine hole and the coarse hole;

[0025] The fine hole is fitted with the wire with a gap to correct the coaxiality error between the wire and the axis of the protective tube.

[0026] The diameter of the coarse pore is larger than the diameter of the fine pore.

[0027] Furthermore, it also includes an H-shaped insulating block that fills the bottom of the cavity;

[0028] The H-shaped insulating block includes two elongated insulating blocks arranged opposite each other and an intermediate insulating block for connecting the two elongated insulating blocks;

[0029] The insulating pad is fixedly connected to the two elongated insulating blocks and the intermediate insulating block as a whole;

[0030] Both sides of the insulating pad are provided with through holes that penetrate the intermediate insulating block in a vertical direction;

[0031] The conductive block passes through the perforation on the corresponding side.

[0032] Furthermore, the protective tube, the insulating ring, the insulating block, the insulating pad, and the H-shaped insulating block are all made of insulating material.

[0033] Beneficial effects:

[0034] Compared with the existing Hopkinson bar test apparatus for studying the microstructure evolution of materials under dynamic loading conditions, the high-speed current-carrying strain test apparatus of this invention has the following characteristics:

[0035] 1. This method departs from the traditional approach of using mechanical impact to generate stress waves to deform the specimen. Instead, it employs a shock wave generated by the explosion of an electric wire to deform the specimen. When the strain rate applied to the specimen needs adjustment, only the circuit voltage needs to be adjusted, making control simple and quick. Furthermore, the shock wave generated by the electric wire explosion can induce strain in the surface structure of the specimen at high strain rates, up to 10. 4 ~10 5 / s, exceeding the strain rate limit of a typical Hopkinson bar experimental setup.

[0036] 2. It can simultaneously induce current in the specimen while generating a high strain rate, overcoming the limitations of traditional testing devices such as universal electronic tensile testing machines and Hopkinson bar testing apparatus, which cannot simultaneously apply 10... 4 The drawbacks of strain rate deformation and current on the order of / s.

[0037] Therefore, by using the above-mentioned high-speed current-carrying strain test device, the shock wave generated by the explosion of the electric wire is used to uniformly bombard the surface of the specimen, which increases the upper limit of the strain rate applied to the specimen and enables the specimen to carry current when bombarded by the shock wave. This solves the technical problem that the current test device has a low upper limit of the strain rate that can be applied to the specimen and cannot enable the material to carry current at high strain rates at the same time. Attached Figure Description

[0038] Figure 1 This is a three-dimensional structural schematic diagram of the high-speed current-carrying strain experimental device of the present invention;

[0039] Figure 2 for Figure 1 Top view of the medium-to-high speed current-carrying strain experimental setup;

[0040] Figure 3 for Figure 2 Sectional view of section AA;

[0041] Figure 4 for Figure 2 Sectional view of section BB;

[0042] Figure 5 This is a schematic diagram of the cross-sectional structure of the plug;

[0043] Figure 6 This is a three-dimensional structural diagram of the H-shaped insulating block and insulating pad.

[0044] Among them, 1-base, 2-protective tube, 3-electric wire, 4-cavity, 5-test piece, 6-insulating pad, 7-conductive block, 8-insulating block, 9-set screw, 10-insulating ring, 11-plug, 12-closing cover, 13-screw, 14-H-shaped insulating block, 51-arc portion, 52-long strip plate, 111-small diameter end, 112-large diameter end, 113-center hole, 1131-narrow hole, 1132-coarse hole, 1133-conical hole, 141-long strip insulating block, 142-intermediate insulating block, 143-perforation Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] This invention provides a high-speed current-carrying strain experimental apparatus, such as... Figure 1 and Figure 2 As shown in the structure, the high-speed current-carrying strain experimental device includes a base 1, a protective tube 2, and an electric wire 3; the protective tube 2 is made of insulating material.

[0047] like Figure 3 and Figure 4As shown, the base 1 is provided with a cavity 4 that is open at both the top and the bottom; the base 1 constitutes the frame of the entire high-speed current-carrying strain test device and can be a hollow U-shaped clamp; the top is used to support the protective tube 2 and the wire 3; the internal cavity 4 is used to install the specimen 5, the conductive block 7, the insulating block 8 and the top wire 9; the insulating block 8 is made of insulating material.

[0048] like Figure 1 and Figure 4 As shown, the protective tube 2 spans the top of the base 1, with both ends fixedly installed on the base 1, for mounting the test piece 5; the electric wire 3 passes through the protective tube 2 and extends along the axis of the protective tube 2, with both ends used to connect to the power supply so that the electric wire 3 explodes and the shock wave generated by the explosion evenly bombards the surface of the test piece 5; the electric wire 3 is insulated from both the protective tube 2 and the base 1.

[0049] like Figure 2 and Figure 3 As shown, the specimen 5 includes an arc-shaped portion 51 and two long strips 52 connected side-by-side to both ends of the arc-shaped portion 51; the arc-shaped portion 51 is used to fit onto the outer circumferential surface of the axial center of the protective tube 2; an insulating pad 6 is sandwiched between the two long strips 52, and the insulating pad 6 is made of insulating material; on the side of the two long strips 52 away from the insulating pad 6, a conductive block 7, an insulating block 8, and a set screw 9 are arranged in sequence, and the set screw 9 is screwed into the base 1 to press the long strip 52 tightly against the insulating pad 6 through the insulating block 8 and the conductive block 7; the bottom ends of the two conductive blocks 7 extend out of the base 1 and form terminals for connecting to a power source, so that the specimen 5 carries current when bombarded by a shock wave; The two long strips 52 of the test piece 5 are used to carry current during the experiment. The long strips 52 are separated by an insulating pad 6 to prevent the two leads of the test piece 5 from contacting or arcing, which would affect the current distribution on the test piece 5. The test piece 5 is electrically connected to the power supply through a conductive block 7 on the outside of the long strips 52. The insulating block 8 is pressed by the set screw 9 to apply pressure to the insulating block 8, so that the gap between the conductive block 7 and the test piece 5 is compacted, ensuring the efficiency of current conduction. The current flowing to the test piece 5 is isolated from the base 1 by the insulating block 8 and the insulating pad 6, ensuring the safety of the experiment and the stability of the current distribution on the test piece 5, and ensuring the stability and consistency of the experimental results.

[0050] In one specific implementation, such as Figure 4As shown, the aforementioned high-speed current-carrying strain test apparatus also includes insulating rings 10, plugs 11, and closing caps 12 disposed at both ends of the protective tube 2. That is, insulating rings 10, plugs 11, and closing caps 12 are disposed at both ends of the protective tube 2. The insulating ring 10 is provided with an annular bushing, a flange fixedly connected to one end of the bushing, and a through hole penetrating the bushing and the flange along the axial direction. The insulating ring 10 is made of insulating material and can isolate the base 1 from the current flowing to the wire 3. The plug 11 is provided with a small diameter end 111 with the same inner diameter as the inner diameter of the protective tube 2, a large diameter end 112 with the same inner diameter as the through hole of the flange, and a central hole 113 penetrating along the axial direction. The top of the base 1 is provided with a top semi-circular groove with a top opening and a threaded hole. The closing cap 12 is provided with a bottom semi-circular groove that corresponds one-to-one with the top semi-circular groove and has a bottom opening. The closing cap 12 is installed on the top of the base 1 by screws 13 that are threaded to the threaded hole. Figure 1 As shown, two opposing closed covers 12 are fixedly installed on the top of the base 1, and one closed cover 12 is provided at each end of the protective tube 2. Each closed cover 12 is connected to the base 1 by two screws 13. The top semi-circular groove and the bottom semi-circular groove that fit together form a space to accommodate an annular bushing. The bushing is accommodated in the corresponding bottom semi-circular groove and the top semi-circular groove, and is pressed onto the base 1 by the closed cover 12. The small diameter end 111 of the plug 11 is inserted into the protective tube 2, and the large diameter end 112 is transitionally fitted. Inside the through hole of the insulating ring 10, the protective tube 2 is limited and supported between the base 1 and the closed cover 12 by the plug 11 and the insulating ring 10; the end of the wire 3 passes through the central hole 113 of the plug 11 and is bent and fixed to the outer end face of the large diameter end 112 of the plug 11. The end of the wire 3 can be fixed to the outer end face of the large diameter end 112 of the plug 11 by copper foil. The plug 11 can be made of metal material. The two ends of the wire 3 are used to connect the power supply to realize the explosion of the wire 3. The two ends of the wire 3 outside the plug 11 can be covered with insulating sleeves.

[0051] Furthermore, such as Figure 5As shown, the central hole 113 of the plug 11 is composed of a fine hole 1131 located in the small diameter end 111, a coarse hole 1132 located in the large diameter end 112, and a tapered hole 1133 connecting the fine hole 1131 and the coarse hole 1132; the fine hole 1131 is clearance-fitted with the electric wire 3 to correct the coaxial error between the electric wire 3 and the axis of the protective tube 2; the diameter of the coarse hole 1132 is larger than the diameter of the fine hole 1131. During installation, the large-diameter end 112 of the plug 11 faces outward from the base 1, while the small-diameter end 111 is located inside the base 1. The large-diameter end 112 has a larger coarse hole 1132, which facilitates the insertion of the wire 3. The wire 3 is guided by the tapered hole 1133 to enter the fine hole 1131 of the small-diameter end 111. Since the inner fine hole 1131 has a smaller diameter and the wire 3 is in clearance fit with the fine hole 1131, the coaxiality of the wire 3 and the protective tube 2 axis can be corrected through the fine hole 1131, ensuring that the distance of the shock wave from each part of the wire 3 to the specimen 5 is basically equal, thereby improving the consistency and stability of the experiment.

[0052] like Figure 3 , Figure 4 and Figure 6 As shown, the above-mentioned high-speed current-carrying strain test device also includes an H-shaped insulating block 14 filled at the bottom of the cavity 4; the H-shaped insulating block 14 is made of insulating material and includes two elongated insulating blocks 141 arranged opposite each other and an intermediate insulating block 142 for connecting the two elongated insulating blocks 141. The arrangement direction of the two elongated insulating blocks 141 is consistent with the extension direction of the electric wire 3, and the intermediate insulating block 142 is fixedly connected between the two elongated insulating blocks 141; the insulating pad 6 is fixedly connected to the two elongated insulating blocks 141 and the intermediate insulating block 142 as a whole; a through hole 143 is provided on both sides of the insulating pad 6, which penetrates the intermediate insulating block 142 in a vertical direction; a conductive block 7 passes through the through hole 143 on one side of the insulating pad 6, and another conductive block 7 passes through the through hole 143 on the other side of the insulating pad 6. The two leads of the test piece 5, namely, the two long strips 52, are fitted on both sides of the middle insulating block 142; the lead of the conductive block 7 passes through the through hole 143 of the middle insulating block 142 and the bottom opening of the base 1 in sequence and extends out of the outside of the base 1, and the upper end of the conductive block 7 is in close contact with the long strips 52 of the test piece 5.

[0053] The H-shaped insulating block 14, which fills the bottom of the cavity 4 inside the base 1, can support the insulating pad 6 between the two long strips 52 of the specimen 5, thereby improving the stability and conductivity reliability of the specimen 5.

[0054] Compared with the existing Hopkinson bar test apparatus for studying the microstructure evolution of materials under dynamic loading conditions, the above-mentioned high-speed current-carrying strain test apparatus has the following characteristics:

[0055] 1. The aforementioned high-speed current-carrying strain test apparatus has a coaxial electric wire 3 installed inside the protective tube 2, with both ends of the electric wire 3 supported on the top of the base 1. This changes the traditional method of using mechanical collision to generate stress waves to deform the specimen 5, instead employing a shock wave generated by the explosion of the electric wire 3 to deform the specimen 5. When it is necessary to adjust the strain rate experienced by the specimen 5, only the circuit voltage needs to be adjusted, making control simple and quick. Furthermore, the shock wave generated by the explosion of the electric wire 3 can induce strain in the surface structure of the specimen 5 at a high strain rate, up to 10. 4 ~10 5 / s, exceeding the strain rate limit of a typical Hopkinson bar experimental setup.

[0056] 2. The aforementioned high-speed current-carrying strain test apparatus has two long strips 52 at the bottom of the specimen 5, with an insulating pad 6 sandwiched between them. On the side of the long strips 52 facing away from the insulating pad 6, a conductive block 7, an insulating block 8, and a set screw 9 are sequentially arranged. The set screw 9, in a screw engagement with the base 1, presses the insulating block 8, conductive block 7, and long strips 52 onto the insulating pad 6, allowing the specimen 5 to carry current while simultaneously generating a high strain rate strain. This overcomes the limitations of traditional test apparatuses such as the universal electronic tensile testing machine and the Hopkinson tensile test apparatus, which cannot simultaneously apply a 10-fold current to the specimen 5. 4 The drawbacks of strain rate deformation and current on the order of / s.

[0057] Therefore, the above-mentioned high-speed current-carrying strain experimental device utilizes electrical energy to generate shock waves through the explosion of the electric wire 3 to bombard the surface of the specimen 5, causing the material structure to produce high strain rate strain, thereby increasing the upper limit of the strain rate applied to the specimen 5. At the same time, the conductive block 7 enables the specimen 5 to carry current when bombarded by the shock wave, providing an experimental platform for studying the evolution of the microstructure of materials under high-speed sliding electrical contact environment. This solves the technical problems of the current experimental device having a low upper limit of the strain rate that can be applied to the specimen 5 and being unable to make the material carry current at high strain rate conditions.

[0058] Before the experiment, first connect the two plugs 11 to the positive and negative terminals of the power supply that powers the wire 3, respectively. Then connect the leads of the two conductive blocks 7 to the positive and negative terminals of the power supply that powers the specimen 5, respectively. During the experiment, connect the two power supplies simultaneously or separately as needed, so that the specimen 5 carries current while the wire 3 explodes, causing the specimen 5 to be impacted and deformed. After the explosion process is over, disconnect the circuit, replace the protective tube 2, the specimen 5, and the wire 3, and proceed to the next set of experiments.

[0059] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-speed current-carrying strain experimental apparatus, characterized in that, Includes base, protective tube, and wire; The base is provided with a cavity that is open at both the top and the bottom; The protective tube spans the top of the base and is fixedly installed at both ends of the base for mounting the test specimen. The electric wire is inserted inside the protective tube and extends along the axis of the protective tube. Both ends are used to connect to a power source so that the electric wire explodes and the shock wave generated by the explosion bombards the surface of the specimen evenly. The electric wire is insulated from the protective tube and the base. The specimen includes an arc portion and two long strips connected side by side to both ends of the arc portion; the arc portion is used to fit onto the outer circumferential surface of the axial middle part of the protective tube; an insulating pad is sandwiched between the two long strips, and a conductive block, an insulating block and a set screw are sequentially arranged on the side of the two long strips away from the insulating pad; The set screw is screwed into the base to press the long strip plate against the insulating pad through the insulating block and the conductive block; The bottom ends of both conductive blocks extend out of the base and form terminals for connecting to a power source, so that the specimen carries current when bombarded by a shock wave. It also includes insulating rings, plugs, and closing caps disposed at both ends of the protective tube; The insulating ring is provided with an annular bushing, a flange fixedly connected to one end of the bushing, and a through hole that passes through the bushing and the flange along the axial direction. The plug is provided with a small diameter end with the same inner diameter as the protective tube, a large diameter end with the same inner diameter as the through hole, and a central hole that extends axially. The base has a top semi-circular groove with a top opening and a threaded hole at the top. The closed cover is provided with a bottom semicircular groove that corresponds one-to-one with the top semicircular groove and has an opening at the bottom; The closing cover is mounted on top of the base by a screw that is threaded into the threaded hole; The small-diameter end of the plug is inserted into the protective tube, and the large-diameter end is fitted into the through hole of the insulating ring. The end of the wire passes through the central hole of the plug, is bent, and fixed to the outer end face of the large-diameter end of the plug; The bushing is housed within the corresponding bottom semicircular groove and the top semicircular groove, and is pressed against the base by the closing cover.

2. The high-speed current-carrying strain experimental apparatus as described in claim 1, characterized in that, The end of the wire is fixed to the outer end face of the large-diameter end of the plug by copper foil.

3. The high-speed current-carrying strain experimental apparatus as described in claim 1, characterized in that, The central hole of the plug is composed of a fine hole located in the small diameter end, a coarse hole located in the large diameter end, and a tapered hole connecting the fine hole and the coarse hole. The fine hole is fitted with the wire with a gap to correct the coaxiality error between the wire and the axis of the protective tube. The diameter of the coarse pore is larger than the diameter of the fine pore.

4. The high-speed current-carrying strain experimental apparatus as described in any one of claims 1-3, characterized in that, It also includes an H-shaped insulating block that fills the bottom of the cavity; The H-shaped insulating block includes two elongated insulating blocks arranged opposite each other and an intermediate insulating block for connecting the two elongated insulating blocks; The insulating pad is fixedly connected to the two elongated insulating blocks and the intermediate insulating block as a whole; Both sides of the insulating pad are provided with through holes that penetrate the intermediate insulating block in a vertical direction; The conductive block passes through the perforation on the corresponding side.

5. The high-speed current-carrying strain experimental apparatus as described in claim 4, characterized in that, The protective tube, the insulating ring, the insulating block, the insulating pad, and the H-shaped insulating block are all made of insulating material.

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