CN114441292A - Processing method of visual extensometer for automatically measuring specified plastic extension strength - Google Patents
Processing method of visual extensometer for automatically measuring specified plastic extension strength Download PDFInfo
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- CN114441292A CN114441292A CN202210102753.8A CN202210102753A CN114441292A CN 114441292 A CN114441292 A CN 114441292A CN 202210102753 A CN202210102753 A CN 202210102753A CN 114441292 A CN114441292 A CN 114441292A
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- extensometer
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- 230000000007 visual effect Effects 0.000 title claims abstract description 12
- 238000003672 processing method Methods 0.000 title abstract description 7
- 238000005259 measurement Methods 0.000 claims abstract description 12
- 238000012360 testing method Methods 0.000 claims description 18
- 238000009864 tensile test Methods 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 5
- 238000013519 translation Methods 0.000 claims description 3
- 229910000831 Steel Inorganic materials 0.000 claims description 2
- 239000010959 steel Substances 0.000 claims description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
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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
- G01N3/02—Details
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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
- G01N3/02—Details
- G01N3/04—Chucks
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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
- G01N3/02—Details
- G01N3/06—Special adaptations of indicating or recording means
- G01N3/068—Special adaptations of indicating or recording means with optical indicating or recording means
-
- 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
Abstract
The invention provides a processing method of a visual extensometer for automatically measuring specified plastic extension strength, which comprises the following steps: s1 distance-marking speckle characteristic point picking; s2 tracking the characteristic points; and S3 calculating the result. Efficiency is improved through automatic measurement, can realize measuring under high temperature and low temperature environment, enlarge video extensometer gauge length scope, and the non-contact measurement improves the security.
Description
Technical Field
The invention relates to the field of visual characteristic images, in particular to a processing method of a visual extensometer for automatically measuring specified plastic extension strength.
Background
The plastic elongation strength Rp is the stress corresponding to the plastic elongation rate equal to the specified extensometer gauge length percentage, for example, the stress corresponding to the plastic elongation length of 50mm 0.002 mm 0.1mm expressed by a 50mm extensometer in Rp0.2 is a common test item for metal products and samples without obvious yield strength after heat treatment, and the extensometer gauge length range adopted by the national standard for the plastic elongation strength Rp is 0.5L0-0.9LCMeanwhile, the contact extensometer can only carry out detection tests at normal temperature, and cannot participate in high temperature and low temperature.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a processing method of a visual extensometer for automatically measuring specified plastic elongation strength.
The invention is realized by the following modes:
the invention relates to a processing method of a visual extensometer for automatically measuring specified plastic extension strength, which comprises the following steps:
s1 scale speckle characteristic point picking: placing a sample to be detected on a clamping jaw of a tensile testing machine, recording characteristic points of the sample through a video camera, inputting the characteristic points into computer image software, and recording speckle characteristics of the characteristic points at two ends of a gauge length by setting an extensometer gauge length through the characteristic points;
s2 feature point tracking: the testing machine starts to stretch, the test sample is stretched by the testing machine, the characteristic points of the extensometer gauge length of the test sample are stretched accordingly, the computer image software tracks the image movement of the characteristic points of the extensometer gauge length of the test sample in real time, and the movement distance between the characteristic points is calculated in real time;
s3 calculation of results: the moving distance between the characteristic points is transmitted to a tensile testing machine in real time and stored in the tensile testing machine software of a computer, the tensile testing machine software is drawn into a stress-strain tensile curve chart by combining the stress data of the tensile testing machine, the line segment in the elastic stage is translated, and the stress corresponding to the intersection point of the translation straight line and the tensile curve is the result of the specified plastic elongation strength.
Further, in the step S1, the extensometer gauge length is set according to different steel grades and different specifications thereof.
Further, if the extensometer gauge length is set to 50mm in the step S1, the computer software automatically identifies the characteristic points of the sample at the two ends of the middle 50 mm.
In S3, the line segment of the elastic phase is translated, and if the plastic elongation strength is 0.2, the computer image software automatically translates 50mm by 0.002 to 0.1mm by using a 50mm extensometer.
The invention has the beneficial effects that: efficiency is improved through automatic measurement, can realize measuring under high temperature and low temperature environment, enlarge video extensometer gauge length scope, and the non-contact measurement improves the security.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention;
FIG. 2 is a schematic diagram of the speckle signature of the recorded feature points of the present invention;
FIG. 3 is a schematic diagram of calculating the moving distance between feature points in real time according to the present invention;
fig. 4 is a stress-strain tensile plot of the present invention.
Detailed Description
The invention will now be further described with reference to the accompanying figures 1-4 and examples of the invention.
The invention relates to a processing method of a visual extensometer for automatically measuring specified plastic extension strength, which comprises the following steps:
s1 scale speckle characteristic point picking: placing a sample to be detected on a clamping jaw of a tensile testing machine, recording characteristic points of the sample through a video camera, inputting computer image software, wherein video images can have obvious edge boundary lines of a real object and a background light source, the scale distance of the extensometer is set to be 50mm, and the computer software automatically identifies the speckle characteristics of the characteristic points of the sample at two ends of 50mm in the middle as shown in figure 2; in the step S1, the extensometer gauge length is set according to different steel types and different specifications thereof, and the extensometer gauge length range adopted for stipulating the plastic extension strength Rp is 0.5L0-0.9LCIn between, the image software adopts 5.65 √ S0Wherein S is0Calculating the cross section area of the sample, and taking or rejecting according to integral multiple of 10;
s2 feature point tracking: the testing machine starts to stretch, the test sample is stretched by the testing machine, the feature points at two ends of 50mm of the extensometer gauge length of the test sample are stretched accordingly, the computer image software tracks the image movement of the feature points at two ends of 50mm of the extensometer gauge length of the test sample in real time, and the movement distance between the feature points is calculated in real time, as shown in fig. 3;
s3 calculation of results: the moving distance between the characteristic points is transmitted to a tensile testing machine in real time and stored in the tensile testing machine software of a computer, the tensile testing machine software is drawn into a stress-strain tensile curve graph by combining the stress data of the tensile testing machine, as shown in fig. 4, the line segment of the elastic stage is translated, and the stress corresponding to the intersection point of the translation straight line and the tensile curve is the plastic elongation strength result Rp; e is the elongation, epIn order to specify the plastic elongation, R is stress, Rp is specified plastic tensile strength, in S3, the line segment of the elastic phase is translated, and according to the national standard, if the plastic tensile strength Rp is specified to be 0.2, a 50mm extensometer is used, and the computer image software automatically translates 50mm by 0.002-0.1 mm.
The invention has the beneficial effects that:
1. the efficiency is improved: the camera captures the speckle characteristics of the material and tracks the movement of the characteristic measurement scale distance characteristic points in real time, time-consuming measurement is not needed, the movement time of the contact type automatic extensometer is saved, and 30 seconds are saved for each sample.
2. The video extensometer has a large scale distance range: the maximum range of the video extensometer can reach 2000mm, which is far beyond 400mm of the contact extensometer, and the video extensometer can adapt to the detection of more varieties and multi-specification samples.
3. The temperature limitation that the contact extensometer cannot measure in high-temperature and low-temperature environments is overcome, and the video extensometer can be used for measuring low temperature, room temperature and high temperature.
4. Non-contact measurement: the non-contact measurement can not apply any external force to the sample and damage the surface of the sample, the slipping phenomenon does not exist, the whole test process is measured, and the safety of an operator is finally ensured through the non-contact measurement.
Claims (4)
1. A process for automatically measuring a visual extensometer of a specified plastic elongation strength comprising the steps of:
s1 scale speckle characteristic point picking: placing a sample to be detected on a clamping jaw of a tensile testing machine, recording characteristic points of the sample through a video camera, inputting the characteristic points into computer image software, and recording speckle characteristics of the characteristic points at two ends of a gauge length by setting an extensometer gauge length through the characteristic points;
s2 feature point tracking: the testing machine starts to stretch, the test sample is stretched by the testing machine, the characteristic points of the extensometer gauge length of the test sample are stretched accordingly, the computer image software tracks the image movement of the characteristic points of the extensometer gauge length of the test sample in real time, and the movement distance between the characteristic points is calculated in real time;
s3 calculation of results: the moving distance between the characteristic points is transmitted to a tensile testing machine in real time and stored in the tensile testing machine software of a computer, the tensile testing machine software is drawn into a stress-strain tensile curve chart by combining the stress data of the tensile testing machine, the line segment in the elastic stage is translated, and the stress corresponding to the intersection point of the translation straight line and the tensile curve is the result of the specified plastic elongation strength.
2. The process for the automatic measurement of the plastic elongation of a visual extensometer as claimed in claim 1, characterized in that: and in the S1, the extensometer gauge length is set according to different steel grades and different specifications thereof.
3. The process for the automatic measurement of the plastic elongation of a visual extensometer as claimed in claim 2, characterized in that: if the extensometer gauge length is set to be 50mm in S1, the computer software automatically identifies the characteristic points of the samples at the two ends of the middle 50 mm.
4. The process for the automatic measurement of the plastic elongation of a visual extensometer as claimed in claim 1, characterized in that: in S3, the line segment of the elastic phase is translated, for example, the plastic elongation strength is 0.2, and the computer image software automatically translates 50mm × 0.002 to 0.1mm by using a 50mm extensometer.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210102753.8A CN114441292A (en) | 2022-01-27 | 2022-01-27 | Processing method of visual extensometer for automatically measuring specified plastic extension strength |
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| CN202210102753.8A CN114441292A (en) | 2022-01-27 | 2022-01-27 | Processing method of visual extensometer for automatically measuring specified plastic extension strength |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101832895A (en) * | 2010-03-26 | 2010-09-15 | 北京纳克分析仪器有限公司 | Visual tensile testing system |
| CN103575227A (en) * | 2013-09-23 | 2014-02-12 | 西安新拓三维光测科技有限公司 | Vision extensometer implementation method based on digital speckles |
| CN103760025A (en) * | 2014-02-10 | 2014-04-30 | 深圳三思纵横科技股份有限公司 | Extensometer and measuring method thereof |
| CN113740155A (en) * | 2021-08-12 | 2021-12-03 | 黄继平 | Automatic measuring equipment for elongation after fracture, maximum force total elongation and reduction of area of metal material |
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2022
- 2022-01-27 CN CN202210102753.8A patent/CN114441292A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101832895A (en) * | 2010-03-26 | 2010-09-15 | 北京纳克分析仪器有限公司 | Visual tensile testing system |
| CN103575227A (en) * | 2013-09-23 | 2014-02-12 | 西安新拓三维光测科技有限公司 | Vision extensometer implementation method based on digital speckles |
| CN103760025A (en) * | 2014-02-10 | 2014-04-30 | 深圳三思纵横科技股份有限公司 | Extensometer and measuring method thereof |
| CN113740155A (en) * | 2021-08-12 | 2021-12-03 | 黄继平 | Automatic measuring equipment for elongation after fracture, maximum force total elongation and reduction of area of metal material |
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