CN113310790B - End reinforcing method for bare conductor tensile test - Google Patents

End reinforcing method for bare conductor tensile test Download PDF

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CN113310790B
CN113310790B CN202010118645.0A CN202010118645A CN113310790B CN 113310790 B CN113310790 B CN 113310790B CN 202010118645 A CN202010118645 A CN 202010118645A CN 113310790 B CN113310790 B CN 113310790B
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reinforcing pipe
reinforcing
epoxy mortar
conductor
fixing device
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CN113310790A (en
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尹恒
郭力
袁飞
张思德
刘晓威
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Southeast University
China Energy Engineering Group Jiangsu Power Design Institute Co Ltd
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Southeast University
China Energy Engineering Group Jiangsu Power Design Institute Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/04—Chucks

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • General Health & Medical Sciences (AREA)
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  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Abstract

The invention discloses an end reinforcing method for a bare conductor tensile experiment, which comprises the steps of reserving the center of a tested bare conductor and a first layer of conductor outside the center, cutting off the rest of conductors, placing an inner layer reinforcing pipe on the outer surface which is lower than the end part of the rest of conductors by a set distance, and placing a fixing device on the outer surface of the inner layer reinforcing pipe; filling epoxy mortar in the gaps among the leads, the inner wall of the inner-layer reinforcing pipe and the gaps among the leads to form epoxy mortar filling sections, and standing to enable the epoxy mortar filling sections to reach the designed strength; and removing the fixing device on the outer surface of the inner reinforcing pipe, bending the central and peripheral wires, uniformly arranging the wires on the outer surface of the inner reinforcing pipe, arranging the outer reinforcing pipe on the outer surface of the bent wires, and placing the fixing device on the outer surface of the outer reinforcing pipe. The end part of the lead is not easy to break in the clamping end, the inner layer material and the outer layer material of the lead can be uniformly stressed, the length of a test piece of the bare lead can be shortened, the method has the advantages of high experiment efficiency, high measurement precision, wide application range and the like, and the experiment cost can be saved.

Description

End reinforcing method for bare conductor tensile experiment
Technical Field
The invention relates to the technical field of bare conductor mechanical property experiments, in particular to an end reinforcing method for a bare conductor tensile experiment.
Background
The tensile test of the bare conductor is an important link for detecting the mechanical property of the conductor. The untreated end of the wire is directly clamped on a testing machine, and the wire can be broken at the clamping end in the stretching process and cannot meet the requirements of experiments and the regulations of relevant specifications.
According to GB/T4909.3-2009, the sampling length of the test piece is 400 times of the diameter of the conducting wire and is not less than 10m. Aiming at the steel-cored aluminum strand type wire, the tensile test of the length sample is difficult to carry out, the sample is dangerous to break, and the mechanical properties are different due to different inner and outer layers of materials.
Disclosure of Invention
The invention aims to: the invention aims to provide an end reinforcing method for a bare conductor tensile test, which solves the problem that the deformation of two materials is inconsistent and the experimental result is influenced due to the fact that the steel wire and the aluminum wire on the inner layer and the outer layer are stressed unevenly or the inner steel wire slides when the untreated conductor end is directly clamped on a testing machine.
The technical scheme is as follows: the invention provides an end reinforcing method for a bare conductor tensile test, which comprises the following steps:
the center of the tested bare conductor and the first layer of conductor outside the center are reserved, the rest conductors are cut off, an inner layer reinforcing pipe is arranged on the outer surface which is lower than the end part of the rest conductors by a set distance, and a fixing device is arranged on the outer surface of the inner layer reinforcing pipe;
filling epoxy mortar into gaps among the leads, the inner wall of the inner-layer reinforcing pipe and gaps among the leads to form epoxy mortar filling sections, and standing to enable the epoxy mortar filling sections to reach the designed strength;
and removing the fixing device on the outer surface of the inner reinforcing pipe, bending the central and peripheral wires, uniformly arranging the wires on the outer surface of the inner reinforcing pipe, arranging the outer reinforcing pipe on the outer surface of the bent wire, and placing the fixing device on the outer surface of the outer reinforcing pipe.
Furthermore, the inner layer reinforcing pipe and the outer layer reinforcing pipe are formed by cutting aluminum pipes or steel pipes or are formed by rolling steel plates with certain rigidity close to the wires.
Furthermore, the fixing device is a hoop.
Furthermore, the placing direction of the inner layer reinforcing pipe and the outer layer reinforcing pipe is perpendicular to the placing direction of the fixing device.
Furthermore, before epoxy mortar is poured, the clamp does not completely tighten the screws, only the fixing position is needed, and the screws are tightened after pouring is completed.
Further, the inner reinforcing tube is placed on the outer surface of the truncated remaining conductor by 1cm below the end portion.
Furthermore, the bottom of the epoxy mortar pouring section is flush with the bottom of the inner-layer reinforced pipe, the height of the epoxy mortar pouring section is consistent with that of the inner-layer reinforced pipe, and the exposed and cut-off lead is poured into the top of the epoxy mortar pouring section.
Furthermore, the placing height of the outer layer reinforcing pipe is consistent with that of the inner layer reinforcing pipe, and the inner wall of the outer layer reinforcing pipe is tightly attached to the bent lead.
Furthermore, the deformable minimum diameter of the inner layer reinforcing tube and the diameter of the bare conductor are required to be different by less than 1mm.
The invention has the beneficial effects that: the invention can shorten the length of a test piece of a bare wire, the end part of the wire is not easy to break in the clamping end in the process of a tensile experiment on the existing testing machine, and the inner layer material and the outer layer material of the wire can be uniformly stressed, thereby having the advantages of high experiment efficiency, high measurement precision, wide application range and the like, and simultaneously saving the experiment cost.
Drawings
FIG. 1 is a schematic view of the anchor reinforcement stage of the present invention;
FIG. 2 is a top plan view of the anchor reinforcement stage of the present invention;
FIG. 3 isbase:Sub>A cross-sectional view taken along line A-A of FIG. 2;
FIG. 4 is an elevation view of the anchor reinforcement stage of the present invention;
FIG. 5 is a schematic view of the anchor forming stage of the present invention;
FIG. 6 is a top view of the anchor forming stage of the present invention;
FIG. 7 is a sectional view taken along line B-B of FIG. 6;
fig. 8 is a side view of the anchor formation stage of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
As shown in fig. 1 to 8, an end reinforcing method for a bare wire drawing test includes the steps of: two stages are as follows:
and (3) anchoring and strengthening stage:
step 1, reserving the center of a tested bare conductor and a first layer of conductor 1 outside the center, cutting off other conductors 2, placing an inner layer reinforcing tube 4 on the outer surface which is lower than the end part of the other conductors 2 by a set distance (for example, 1 cm), and placing a fixing device 5 on the outer surface of the inner layer reinforcing tube 4; the placing direction of the fixing device 5 is vertical to the placing direction of the inner layer reinforcing pipe 4;
step 2, filling epoxy mortar in gaps among the leads, the inner wall of the inner-layer reinforcing pipe and gaps among the leads to form an epoxy mortar filling section, and enabling the epoxy mortar filling section to reach the designed strength after standing;
the fixing device 5 does not need to completely screw the screws before epoxy mortar is poured, only needs to fix the position, and screws the screws after pouring is completed.
The bottom of the epoxy mortar pouring section is flush with the bottom of the inner-layer reinforced pipe, the height of the epoxy mortar pouring section is consistent with that of the inner-layer reinforced pipe, and the exposed lead can be poured into the top of the epoxy mortar pouring section.
And (3) an anchoring forming stage:
and 3, removing the fixing devices 5 on the outer surface of the inner reinforcing pipe 4, bending the central and peripheral wires, uniformly arranging the wires on the outer surface of the inner reinforcing pipe 4, arranging the outer reinforcing pipe 6 on the outer surface of the bent wires, and placing the fixing devices 5 on the outer surface of the outer reinforcing pipe 6.
The inner layer reinforcing pipe and the outer layer reinforcing pipe can be formed by cutting aluminum pipes or steel pipes or by rolling steel plates with certain rigidity close to the conducting wires, and the like, and the difference between the deformable minimum diameter of the inner layer reinforcing pipe and the diameter of the bare conducting wire needs to be less than 1mm.
The fixing device can use a clamp with a corresponding specification or other fixing device.
The stranded wires need to be tightly attached to the inner layer reinforcing pipe and the outer layer reinforcing pipe, the placing direction of the inner layer reinforcing pipe is perpendicular to the placing direction of the fixing device, and gaps are prevented from appearing at the joint of the reinforcing pipes and the contact positions of the reinforcing pipes and the conducting wires.
The placing height of the outer reinforcing pipe is consistent with the placing height of the inner reinforcing pipe, and the inner wall of the outer reinforcing pipe needs to be tightly attached to the bent wire, so that the integrity of the anchoring and reinforcing section of the bare wire is improved.
Example 2:
taking an aluminum conductor steel reinforced as an example, the end part reinforcing method for the tensile test of the bare conductor comprises the following steps: two stages are as follows:
and (3) anchoring and strengthening stage:
step 1, reserving the center of a tested steel-cored aluminum strand and a first layer of steel wire 1 outside the center, cutting off other aluminum wires 2, placing an inner layer reinforcing pipe 4 on the outer surface which is lower than the end part of the other wires 2 by a set distance (for example, 1 cm), and placing a fixing device 5 on the outer surface of the inner layer reinforcing pipe 4; the placing direction of the fixing device 5 is vertical to the placing direction of the inner layer reinforcing pipe 4;
specifically, the compound wires at the end parts of the test piece are untied, the compound wires are separated and carefully straightened by hand, the steel wires 1 in the center and around the bare conductor are reserved, the aluminum wires 2 on the outer three layers are cut off, whether the steel wires 1 are straight or not is observed, and if obvious bending is found, the steel wires 1 can be placed on a wooden pad and lightly tapped to be straight by a wooden mallet.
The inner layer reinforced pipe 4 is placed on the outer surface which is lower than the end part 1cm of the aluminum wire 2, meanwhile, one fixing device 5 is respectively placed on the upper surface and the lower surface of the inner layer reinforced pipe 4, the placing direction of the fixing device 5 is vertical to the placing direction of the inner layer reinforced pipe 4, and the screw of the fixing device 5 is not required to be completely screwed down and only needs to be fixed in position
Step 2, filling epoxy mortar in gaps among the leads, the inner wall of the inner-layer reinforcing pipe and gaps among the leads to form an epoxy mortar filling section, and enabling the epoxy mortar filling section to reach the designed strength after standing;
specifically, the inner layer steel wire 1 is separated, epoxy mortar 3 is poured into a gap between the steel wire 1 and the aluminum wire 2 and a gap between the aluminum wire 2 and the inner layer reinforcing pipe 4, the bottom of a pouring section is flush with the bottom of the inner layer reinforcing pipe 4, the height of the pouring section is consistent with that of the inner layer reinforcing pipe 4, and the exposed aluminum wire 2 can be poured into the top of the pouring section. The reinforcing pipe is lightly knocked by a mallet in the filling process to ensure that the colloid is compact and has no cavity. And after the pouring is finished, screwing down the screw of the fixing device 5, and standing for a certain time to solidify the epoxy mortar in the anchoring section.
And (3) an anchor forming stage:
and 3, removing the fixing devices 5 on the outer surface of the inner reinforcing pipe 4, bending the central and peripheral wires, uniformly arranging the wires on the outer surface of the inner reinforcing pipe 4, arranging the outer reinforcing pipe 6 on the outer surface of the bent wires, and placing the fixing devices 5 on the outer surface of the outer reinforcing pipe 6.
Specifically, the fixing device 5 outside the inner reinforcing pipe 4 is removed, the position of the inner reinforcing pipe 4 is kept still, the steel wire 1 at the center of a bare conductor and around the bare conductor is bent, the outer surface of the inner reinforcing pipe 4 is uniformly arranged, then the outer reinforcing pipe 6 is placed on the outer surface of the steel wire 1, the outer surface of the bent steel wire 1 and the inner reinforcing pipe 4 is in close contact with the inner surface of the outer reinforcing pipe 6, the outer reinforcing pipe 6 and the inner reinforcing pipe 4 are placed at a certain staggered angle in the joint position, and therefore a weak face is prevented from being formed. Meanwhile, the fixing devices 5 are respectively arranged on the upper part and the lower part of the outer surface of the outer layer reinforcing pipe 6, the arrangement direction of the fixing devices 5 is vertical to the arrangement direction of the outer layer reinforcing pipe 6, and the fixing devices 5 are screwed so as to reinforce the integral strength of the bare conductor anchoring section.
During the experiment, the anchoring and reinforcing section at the end part of the bare conductor obtained by the method is placed in a clamp of a testing machine, the loading rate of the testing machine is controlled to realize the uniform stress of the steel wire and the aluminum wire at the inner layer and the outer layer of the bare conductor, so that the bare conductor is not easy to break in the clamping end, and meanwhile, the length of a test piece can be shortened, thereby meeting the requirements of relevant specifications. The device has the advantages of high experimental efficiency, high measurement precision, wide application range and the like, and can save the experimental cost.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims (7)

1. An end reinforcing method for a bare conductor tensile test is characterized by comprising the following steps:
the center of the tested bare conductor and the first layer of conductor outside the center are reserved, the rest conductors are cut off, an inner layer reinforcing pipe is arranged on the outer surface which is lower than the end part of the rest conductors by a set distance, and a fixing device is arranged on the outer surface of the inner layer reinforcing pipe;
filling epoxy mortar in the gaps among the leads, the inner wall of the inner-layer reinforcing pipe and the gaps among the leads to form epoxy mortar filling sections, and standing to enable the epoxy mortar filling sections to reach the designed strength;
removing the fixing device on the outer surface of the inner reinforcing pipe, bending the central and peripheral wires, uniformly arranging the wires on the outer surface of the inner reinforcing pipe, arranging the outer reinforcing pipe on the outer surface of the bent wire, and placing the fixing device on the outer surface of the outer reinforcing pipe;
the placing direction of the inner layer reinforcing pipe and the outer layer reinforcing pipe is vertical to the placing direction of the fixing device;
the deformable minimum diameter of the inner reinforcing tube is required to be less than 1mm different from the diameter of the bare conductor.
2. The end reinforcing method for the tensile test of the bare conductor according to claim 1, wherein the inner and outer reinforcing pipes are cut from aluminum pipes or steel pipes or are made by rolling steel plates with certain rigidity close to the conductor.
3. The method of claim 1, wherein the fixture is a clamp.
4. The method for reinforcing the end part of the bare conductor tensile test according to claim 3, wherein the clamp does not completely tighten the screw before the epoxy mortar is poured, only needs to be fixed in position, and the screw is tightened after the epoxy mortar is poured.
5. The method of claim 1, wherein the inner reinforcing tube is disposed on the outer surface of the cut-off remaining conductor by 1cm below the end of the cut-off remaining conductor.
6. The method as claimed in claim 1, wherein the bottom of the epoxy mortar pouring section is flush with the bottom of the inner reinforcing pipe, the height of the epoxy mortar pouring section is consistent with that of the inner reinforcing pipe, and the top of the epoxy mortar pouring section is poured with the exposed and cut-off wires.
7. The end part reinforcing method for the bare conductor stretching experiment according to claim 1, wherein the placing height of the outer layer reinforcing tube is consistent with that of the inner layer reinforcing tube, and the inner wall of the outer layer reinforcing tube is tightly attached to the bent conductor.
CN202010118645.0A 2020-02-26 2020-02-26 End reinforcing method for bare conductor tensile test Active CN113310790B (en)

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CN113310790B true CN113310790B (en) 2023-03-28

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101764290B (en) * 2009-12-21 2012-03-28 中国电力科学研究院 Connecting tube used for large-section conducting wire
JP2011257289A (en) * 2010-06-10 2011-12-22 Tokyo Electric Power Co Inc:The Grip tool for tension tester
CN102980800A (en) * 2011-09-05 2013-03-20 远东电缆有限公司 Fixing device and method for breaking test of carbon fiber composite core aerial conductor
CN104344995A (en) * 2013-07-31 2015-02-11 中国科学院金属研究所 Tensile test method for bent aluminium alloy overhead stranded conductor used for power grids
CN104617516A (en) * 2015-01-30 2015-05-13 国家电网公司 Construction process for reversely pressing strain clamp of carbon fiber conductor
CN105181443A (en) * 2015-07-15 2015-12-23 国家电网公司 Horizontal tension tester's fixture for round wire concentric-lay-stranded overhead conductors

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