CN115290462A - Method for measuring deformation displacement of test piece in high-temperature tensile test - Google Patents
Method for measuring deformation displacement of test piece in high-temperature tensile test Download PDFInfo
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- CN115290462A CN115290462A CN202210894424.1A CN202210894424A CN115290462A CN 115290462 A CN115290462 A CN 115290462A CN 202210894424 A CN202210894424 A CN 202210894424A CN 115290462 A CN115290462 A CN 115290462A
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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
- G01N3/18—Performing tests at high or low temperatures
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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
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- G01N3/06—Special adaptations of indicating or recording means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
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Abstract
A method for measuring deformation displacement of a test piece in a high-temperature tensile test belongs to the technical field of experimental mechanics high-temperature testing, and solves the problems that an electronic element cannot resist high temperature and has low precision in the deformation displacement measurement in a high-temperature environment. The method is realized by a high-temperature displacement measuring module, a normal-temperature displacement measuring module and a connecting module. A pair of high-temperature resistant slide blocks are arranged in the high-temperature box, are respectively connected with the telescopic high-temperature contacts and can slide along a guide rod parallel to the axis of the test piece; each sliding block is connected to a lower normal-temperature sliding block and an upper normal-temperature sliding block which are arranged outside the high-temperature box and on the same axis in a staggered mode through a high-temperature-resistant and inelastic silk thread, and the displacement of the high-temperature environment is converted into the normal-temperature environment; and then measuring the dynamic relative displacement of the two normal-temperature slide blocks by a normal-temperature extensometer and introducing the relative displacement into a tensile test system. The method breaks through the limitation of a high-temperature environment on the displacement measurement electronic element, has the characteristics of wide application range, high measurement precision and low cost, and is suitable for measuring the deformation displacement of a metal tensile test in a large temperature range.
Description
Technical Field
The invention relates to a high-temperature test technology of experimental mechanics, in particular to a method for measuring deformation displacement of a test piece in a high-temperature tensile test.
Background
With the continuous improvement of the environment on the energy-saving requirement and the endurance requirement of the electric automobile, the light weight of the automobile is the trend of the future development of the automobile, and the automobile has great development potential. The forming of various lightweight materials such as high-strength automobile steel, aluminum alloy, magnesium alloy and the like becomes a hot spot in the prior art. These materials tend to be difficult to form at ordinary temperatures and have good formability under heating. The high-temperature mechanical property is the basis and necessary condition of material high-temperature forming process design and simulation analysis, the high-temperature tensile test is one of the most common methods for testing the high-temperature mechanical property of metal materials, the high-temperature tensile test is usually carried out in a closed high-temperature box equipped with a testing machine, deformation displacement measurement methods combined with an experimental system have two types of contact and non-contact, the contact type mainly adopts a extensometer to directly measure, and the non-contact type adopts digital image related technology to measure.
Compared with the normal temperature, the high-temperature tensile test has certain particularity: firstly, deformation displacement cannot be measured by using a common extensometer in a high-temperature environment, a special high-temperature extensometer is required, but the high-temperature extensometer is small in applicable temperature range and high in cost; secondly, the high-temperature deformation displacement is measured by adopting the digital image correlation technology, and the influence of the hot air flow disturbance in the high-temperature environment on the measurement precision is larger.
Therefore, some special clamps for warm forming tensile tests are developed in the market, for example, a clamp for a thermoforming tensile test is developed by New Sansi Material detection Limited company in Shenzhen, and the displacement in the heating furnace can be led out of the furnace; however, when the strain of the test piece is large, the protrusion of the gauge length position in the middle of the tensile test piece is easy to deform under the pulling of the leading-out rod, so that the displacement measurement precision is reduced. CN 101608988 discloses a unidirectional tensile test fixture for warm forming of metal sheet, which uses a displacement extraction rod to extract the deformation displacement of a high-temperature environment for measurement, but two problems need to be solved, firstly, the tension adjustment has significant influence on the measurement precision; secondly, the volume of the leading-out rod is large, and uneven temperature distribution is easily caused at an outlet.
Disclosure of Invention
The invention aims to solve the problems of small use temperature range, low measurement precision, high cost and the like in the prior art in deformation displacement measurement in a high-temperature tensile test, and provides a method for measuring the deformation displacement of a test piece in the high-temperature tensile test.
The invention is realized by adopting the following technical scheme: a method for measuring deformation displacement of a test piece in a high-temperature tensile test comprises the steps of leading out high-temperature deformation displacement through a high-temperature slide block, connecting the high-temperature deformation displacement to two normal-temperature slide blocks through a high-temperature resistant silk thread, measuring relative displacement between the two normal-temperature slide blocks through a normal-temperature extensometer, and leading displacement signals into a tensile test system after acquiring displacement signals.
Further, the method specifically comprises the following steps:
step one, installing a high-temperature displacement measuring module 2, and installing a test piece 23 between an upper high-temperature chuck 211 and a lower high-temperature chuck 212 in a high-temperature box 1; placing the upper high-temperature slide block 261 and the lower high-temperature slide block 262 on the high-temperature guide rod 27, and installing the high-temperature guide rod 27 between the upper fixed end 241 and the lower fixed end 242 of the high-temperature support; the upper high-temperature slide block 261 is connected with the upper fixed end 241 of the high-temperature bracket through an upper high-temperature spring 251, and the lower high-temperature slide block 262 is connected with the lower fixed end 242 of the high-temperature bracket through a lower high-temperature spring 252; the upper high-temperature contact 221 and the lower high-temperature contact 222 are respectively and fixedly arranged on an upper high-temperature slide block 261 and a lower high-temperature slide block 262, and the contacts are in contact with the surface of the test piece 23 to ensure certain contact force;
step two, installing a normal temperature displacement measurement module 5, placing an upper normal temperature slide block 521 and a lower normal temperature slide block 522 on the normal temperature guide rod 53 and enabling the upper and lower slide blocks to slide up and down, wherein the normal temperature guide rod 53 is fixedly installed between an upper fixed end 511 and a lower fixed end 512 of a normal temperature support, and the axis of the normal temperature guide rod 53 is required to be parallel to the axis of the test piece 23; the upper normal temperature slide block 521 is connected with the upper fixed end 511 of the normal temperature bracket through an upper normal temperature spring 541, and the lower normal temperature slide block 522 is connected with the lower fixed end 512 of the normal temperature bracket through a lower normal temperature spring 542;
thirdly, connecting the high-temperature displacement measuring module 2 and the normal-temperature displacement measuring module 5, and connecting the upper high-temperature slide block 261 and the lower high-temperature slide block 262 with the lower normal-temperature slide block 522 and the upper normal-temperature slide block 521 in a staggered manner through the upper high-temperature resistant wire 31 and the lower high-temperature resistant wire 32 respectively;
step four, the system is balanced and adjusted, and the upper tensioning wheel 41 and the lower tensioning wheel 42 are respectively rotated to tension the upper high-temperature-resistant wire 31 and the lower high-temperature-resistant wire 32; the upper high-temperature spring 251 and the lower normal-temperature spring 542 are adjusted to enable the upper high-temperature slide block 261 and the lower normal-temperature slide block 522 to be in a balanced state; adjusting the lower high-temperature spring 252 and the upper normal-temperature spring 541 to keep the lower high-temperature slider 262 and the upper normal-temperature slider 521 in a balanced state;
step five, respectively contacting an extensometer upper contact 611 and an extensometer lower contact 612 of the normal temperature extensometer 6 with an upper normal temperature slide block 521 and a lower normal temperature slide block 522; and the normal temperature extensometer 6 collects displacement signals and guides the displacement signals into a tensile test system to finish deformation displacement measurement.
Further, the test piece 23 in the step one is installed, and the axis of the test piece 23 is required to be consistent with the stretching direction; mounting the high-temperature guide rod 27 in the step one, wherein the axis of the high-temperature guide rod 27 is required to be parallel to the axis of the test piece 23;
preferably, the step one contacts the upper high temperature contact 221 and the lower high temperature contact 222 with the test piece 23 to ensure a certain contact force, and the contact force can be bound to the test piece 23 through a high temperature resistant spring.
Further, the equilibrium state in step four means that a small force is applied to the upper high temperature slider 261, and the upper high temperature slider 261 and the lower normal temperature slider 522 can move by the same small displacement.
Preferably, the step four is to tension the upper high temperature resistant wire 31 and the lower high temperature resistant wire 32 with a tension of 10N.
Preferably, in the fourth step, the extensometer upper contact 611 and the extensometer lower contact 612 are respectively in contact with the upper normal temperature slider 521 and the lower normal temperature slider 522, and are bound by rubber bands to generate a certain contact pressure.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the displacement measurement method, the displacement in the high-temperature environment is converted into the normal-temperature environment for measurement, compared with the traditional displacement measurement method, the influence of the high-temperature environment on an electronic element is overcome, the temperature application range is expanded, the measurement precision is improved, and the cost is reduced.
(2) The high-temperature displacement measuring module and the normal-temperature displacement measuring module are connected by the high-temperature resistant silk threads, the size of the lead-out hole of the high-temperature box is not required, the high-temperature displacement measuring module can be matched with most high-temperature boxes, and the application range is wide.
(3) The high-temperature sliding block and the normal-temperature sliding block are respectively connected to the corresponding fixed ends through springs, and the tension of the silk threads is balanced and adjusted by the tension wheel, so that the influence of external resistance on displacement change is eliminated, and the displacement measurement precision is obviously improved.
Drawings
FIG. 1 is a schematic diagram of the principle of the present invention for measuring the deformation displacement in a high temperature environment converted to a normal temperature environment.
Fig. 2 is an enlarged scale view of the displacement measuring module in the high temperature environment of fig. 1.
Fig. 3 is an enlarged scale view of the displacement measuring module in the normal temperature environment of fig. 1.
Description of the reference numerals
1-high temperature box, 2-high temperature displacement measuring module, 211-upper high temperature chuck, 212-lower high temperature chuck, 221-upper high temperature contact, 222-lower high temperature contact, 23-test piece, 241-upper high temperature support fixed end, 242-lower high temperature support fixed end, 251-upper high temperature spring, 252-lower high temperature spring, 261-upper high temperature slide block, 262-lower high temperature slide block, 27-high temperature guide rod; 31-upper high temperature resistant wire, 32-lower high temperature resistant wire, 41-upper tension wheel, 42-lower tension wheel, 5-room temperature displacement measuring module, 511-room temperature support upper fixing end, 512-room temperature support lower fixing end, 521-upper room temperature sliding block, 522-lower room temperature sliding block, 53-room temperature guide rod, 541-upper room temperature spring, 542-lower room temperature spring, 6-room temperature extensometer, 611-extensometer upper contact, 612-extensometer lower contact.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It is specifically pointed out that several variations and modifications are possible in the light of the above teachings and are within the scope of the invention.
In the embodiment, the sample is a 7075-T6 aluminum alloy plate, the thickness is 2mm, the gauge length is 50mm, and other sizes are made according to GB/T228.2-2015. The temperature range of the high-temperature box is 0-1000 ℃, and the high-temperature box is suitable for stretching most metal materials.
The embodiment provides a displacement measurement method suitable for a material high-temperature tensile test, the principle schematic diagram of the method is shown in fig. 1, and the method mainly comprises a high-temperature box 1, a high-temperature displacement measurement module 2 and a normal-temperature displacement measurement module 5, wherein the high-temperature tensile test is performed in the high-temperature box 1.
An enlarged view of the high temperature displacement measuring module 2 is shown in fig. 2. The test piece 23 is mounted between the upper high temperature chuck 211 and the lower high temperature chuck 212; the high-temperature guide rod 27 is fixedly arranged between the upper fixed end 241 and the lower fixed end 242 of the high-temperature support, and the axis of the high-temperature guide rod 27 is parallel to the axis of the test piece 23; the upper high-temperature slide block 261 and the lower high-temperature slide block 262 are arranged on the high-temperature guide rod 27 and can slide up and down along the high-temperature guide rod 27; the upper high temperature slider 261 is connected with the upper fixed end 241 of the high temperature support through an upper high temperature spring 251, and the lower high temperature slider 262 is connected with the lower fixed end 242 of the high temperature support through a lower high temperature spring 252; the upper high-temperature contact 221 is fixedly connected with the upper high-temperature slide block 261, and the lower high-temperature contact 222 is fixedly connected with the lower high-temperature slide block 262; the upper high-temperature contact 221 and the lower high-temperature contact 222 are respectively in contact with the surface of the test piece 23, the upper and lower intervals are 50mm, and the upper and lower intervals are bound by a high-temperature-resistant spring to provide certain contact pressure.
An enlarged view of the room temperature displacement measuring module 5 is shown in fig. 3. The normal temperature guide rod 53 in the normal temperature displacement measurement module 5 is fixedly arranged between the upper fixed end 511 and the lower fixed end 512 of the normal temperature bracket, and the upper normal temperature slide block 521 and the lower normal temperature slide block 522 are arranged on the normal temperature guide rod 53 and can slide up and down; the upper high-temperature slide block 261 and the lower high-temperature slide block 262 are connected with the lower normal-temperature slide block 522 and the upper normal-temperature slide block 521 in a staggered manner through the upper high-temperature resistant wire 31 and the lower high-temperature resistant wire 32 respectively; the extensometer upper contact 611 and the extensometer lower contact 612 are respectively contacted with the upper normal temperature slide block 521 and the lower normal temperature slide block 522 and are bound by rubber bands to keep certain contact pressure; and finally, the normal temperature extensometer 6 collects displacement signals and guides the displacement signals into a tensile test system. The method transfers the measurement of the deformation displacement of the sample in the high-temperature environment to the normal-temperature environment outside the high-temperature box, and adopts the normal-temperature extensometer to carry out the measurement, so that the method solves the problems that the electronic element cannot work in the high-temperature environment or has low precision, and the cost is greatly reduced.
Claims (6)
1. A method for measuring deformation displacement of a test piece in a high-temperature tensile test is characterized by comprising the following steps: step one, installing a high-temperature displacement measuring module, fixedly installing a test piece 23 between an upper high-temperature chuck 211 and a lower high-temperature chuck 212, placing an upper high-temperature slide block 261 and a lower high-temperature slide block 262 on a high-temperature guide rod 27, fixedly connecting an upper high-temperature contact 221 and a lower high-temperature contact 222 with the upper high-temperature slide block 261 and the lower high-temperature slide block 262 in the vertical direction respectively, and contacting the other ends with the surface of the test piece 23 respectively; step two, mounting a normal temperature displacement measurement module, namely vertically and fixedly mounting a normal temperature guide rod 53 between an upper fixed end 511 and a lower fixed end 512 of an upper normal temperature support, placing an upper normal temperature slide block 521 and a lower normal temperature slide block 522 on the normal temperature guide rod 53 to be capable of sliding up and down, respectively contacting an upper contact 611 of an extensometer and a lower contact 612 of the extensometer with the surfaces of the upper normal temperature slide block 521 and the lower normal temperature slide block 522, binding the upper contact with the upper normal temperature slide block and the lower normal temperature slide block through rubber bands to keep a certain contact pressure, and guiding signals of a normal temperature extensometer 6 into a test system; step three, connecting the upper high-temperature slide block 261 and the lower high-temperature slide block 262 with the lower normal-temperature slide block 522 and the upper normal-temperature slide block 521 in a staggered manner through the upper high-temperature resistant wire 31 and the lower high-temperature resistant wire 32 respectively; step four, adjusting the tension of the upper high-temperature resistant wire 31 and the lower high-temperature resistant wire 32; and step five, starting a tensile test system to start the test, and finishing the high-temperature tensile test.
2. A method for measuring specimen deformation displacement in high temperature tensile test according to claim 1, wherein the axis of the high temperature guide rod 27 in the first step is parallel to the axis of the specimen 23.
3. The method for measuring the deformation displacement of the test piece in the high-temperature tensile test according to claim 2, wherein in the step one, the upper high-temperature contact 221 and the upper high-temperature slide 261 are fixedly connected in the vertical direction, and have no relative displacement in the axial direction of the high-temperature guide rod 27 and can have relative displacement in the horizontal direction; the lower high temperature contact 222 and the lower high temperature slider 262 are not displaced relative to each other in the axial direction of the high temperature guide rod 27, and are displaced relative to each other in the horizontal direction.
4. The method for measuring the deformation displacement of the test piece in the high-temperature tensile test according to claim 3, wherein the dislocation connection in the third step is that the upper high-temperature slide block 261 is connected with the lower normal-temperature slide block 522, and the lower high-temperature slide block 262 is connected with the upper normal-temperature slide block 521.
5. The method for measuring the deformation displacement of the test piece in the high-temperature tensile test according to claim 4, wherein the tension adjusting in the fourth step is to rotate the upper tension wheel 41 to tension the upper high-temperature resistant wire 31, so that the upper high-temperature slide block 261 and the lower normal-temperature slide block 522 are in dynamic balance; the lower tension wheel 42 is rotated to tension the lower high temperature resistant wire 32, so that the lower high temperature slide block 262 and the upper normal temperature slide block 521 are in dynamic balance.
6. The method for measuring the deformation displacement of the test piece in the high-temperature tensile test according to claim 5, wherein the dynamic balance means that the lower normal-temperature slide 522 generates a reverse displacement with the same magnitude for any small displacement of the upper high-temperature slide 261; for any small displacement of the lower high temperature slide block 262, the upper normal temperature slide block 521 will generate a reverse displacement with the same magnitude.
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| CN202210894424.1A CN115290462A (en) | 2022-07-28 | 2022-07-28 | Method for measuring deformation displacement of test piece in high-temperature tensile test |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116296738A (en) * | 2023-05-17 | 2023-06-23 | 华北电力科学研究院有限责任公司 | Bolt thermal stress simulation experiment device and experiment method thereof |
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2022
- 2022-07-28 CN CN202210894424.1A patent/CN115290462A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116296738A (en) * | 2023-05-17 | 2023-06-23 | 华北电力科学研究院有限责任公司 | Bolt thermal stress simulation experiment device and experiment method thereof |
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