CN114280157A - Sub-surface crack length quantitative detection method based on laser excitation surface wave - Google Patents
Sub-surface crack length quantitative detection method based on laser excitation surface wave Download PDFInfo
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- 238000001514 detection method Methods 0.000 title claims abstract description 33
- 230000005284 excitation Effects 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 33
- 239000000523 sample Substances 0.000 claims abstract description 30
- 238000010897 surface acoustic wave method Methods 0.000 claims abstract description 6
- 238000003754 machining Methods 0.000 abstract description 10
- 239000000463 material Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000002604 ultrasonography Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000012625 in-situ measurement Methods 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 230000005381 magnetic domain Effects 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
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Abstract
The invention discloses a subsurface crack length quantitative detection method based on laser excitation surface waves. The method comprises the following steps: 1) placing a pulse laser probe and a laser vibration meter probe on one side of the sub-surface crack of the workpiece, wherein the laser vibration meter probe is positioned between the pulse laser probe and the sub-surface crack; 2) the pulse laser probe emits pulse laser, excites the surface acoustic wave on the surface of the workpiece, and measures the surface wave echo signal reflected by the surface wave on the subsurface crack by using a laser vibration meter; 3) extracting the time t corresponding to the first trough of the echo signal of the surface waveR1And time t corresponding to the second troughR2(ii) a 4) Using time tR1And tR2Calculating the length l of the subsurface crack; the invention can be used for sub-surface crack length in the machining processIn-situ detection can also be used for detecting the length of the subsurface crack in special environments such as high temperature and high pressure.
Description
Technical Field
The invention relates to the field of quantitative nondestructive detection, in particular to a subsurface crack length quantitative detection method based on laser excitation surface waves.
Background
In precision/ultra-precision machining, although the machining force is small, it is also easy to cause some microcracks, such as indentations, below the surface of the material. These cracks, which are sub-surface cracks, are about a hundred microns deep below the surface and have a size of between a few microns and tens of microns. Because precision/ultra-precision machined parts are often used in important parts, such as blades of aircraft engines. The existence of subsurface cracks not only greatly reduces the strength of parts, but also can cause serious safety accidents, and cause serious economic loss. Therefore, numerous scholars are devoted to studying methods for detecting subsurface cracks. At present, methods for finding and locating subsurface cracks are well established, but quantitative detection of subsurface crack length remains a difficult problem.
In the existing research, Tanaka et al have set up a set of laser ultrasonic detection system based on confocal fabry-perot interference method. The system can detect the micro-defects with the defect diameter to ultrasonic wavelength ratio of about 0.07 by detecting the defects through transmitting longitudinal waves and transmitting transverse waves, has high sensitivity and resolution, but cannot realize quantitative detection. Steen et al have detected a weld crack in a chip, excited ultrasound from the chip surface, detected a crack echo by a michelson interferometer, imaged the weld area with a C scan, and detected a weld subsurface crack, but this systematic imaging method is not capable of quantitative crack measurement. Kenderian et al developed a non-contact non-destructive inspection system based on pulsed laser-excited ultrasound and air-coupled transducer-received ultrasound, the pulsed laser of which could be ultrasonically excited several meters away from the part under test, while the system could be used for ultrasonic detection of rough or black surfaces due to the use of air-coupled transducers. But the detection accuracy and resolution of the system still need to be improved. Other non-destructive inspection methods, such as laser scattering techniques, use the scattering properties of sub-surface cracks to laser light to cause changes to the polarization properties of the laser light to invert the crack information, but such techniques can only be used for crack detection of transparent or translucent engineering materials. The acoustic emission technology detects elastic waves generated by rapid release of local energy caused by crack propagation, stress relaxation, friction, leakage, magnetic domain wall motion and the like in a material to realize detection and evaluation of structural integrity of a sample, but is difficult to provide quantitative crack detection and imaging, has low signal-to-noise ratio and needs external excitation to generate an acoustic emission signal.
If the length of the subsurface crack can be quantitatively detected, the corresponding relation between the crack parameters and the processing parameters can be established, the processing technology is optimized, and the subsurface crack can be conveniently removed in the subsequent processing. Among the existing non-destructive testing methods, there are few methods that can quantitatively measure the length of sub-surface cracks. The method can be used for quantitatively measuring the length of the subsurface crack, and has the characteristics of simplicity, high detection speed and high precision. The invention also has the characteristic of non-contact detection, and can be used for in-situ measurement in the processing process or quantitative detection of the length of the subsurface crack in the extreme environment such as high temperature and high pressure.
Disclosure of Invention
The invention provides a method for quantitatively detecting the length of a subsurface crack based on a laser excitation surface wave, which aims to quantitatively detect the length of the subsurface crack generated in a machining process so as to establish a corresponding relation between a machining parameter and a subsurface crack parameter and guide subsequent machining to remove the subsurface crack. The specific scheme is as follows:
the subsurface crack length quantitative detection method based on the laser excitation surface wave comprises the following steps:
1) and placing a pulse laser probe and a laser vibration meter probe on one side of the measured subsurface crack, wherein the laser vibration meter probe is positioned between the pulse laser probe and the subsurface crack.
2) The pulse laser probe emits pulse laser to irradiate on a workpiece, the surface acoustic wave is excited on the surface of the workpiece, and a surface wave echo signal R reflected by the surface wave on the subsurface crack is measured by using a laser vibration meter.
3) Extracting the time t corresponding to the first trough of the surface wave echo signal RR1And time t corresponding to the second troughR2。
4) Calculating the length l-v of the subsurface crackR(tR2-tR1) 2; wherein v isRThe propagation speed of the ultrasonic surface wave on the surface of the workpiece to be measured.
Preferably, in the step 2), the excitation method of the ultrasonic surface wave is laser point source excitation, specifically, pulse laser emitted by a pulse laser probe is focused into point source laser through a convex lens, and the point source laser irradiates the surface of the workpiece and excites the ultrasonic surface wave.
Preferably, in the step 2), the excitation method of the surface acoustic wave is line source excitation, specifically, pulse laser emitted by a pulse laser probe is focused into line source laser through a cylindrical lens, and the line source laser irradiates the surface of the workpiece and excites the surface acoustic wave.
Preferably, the sub-surface crack to be detected is a rectangular crack, and the line source laser emitted by the pulse laser probe is parallel to the axial direction of the sub-surface crack.
Preferably, the propagation speed of the ultrasonic surface wave on the surface of the workpiece is obtained by searching the ultrasonic velocity table in advance.
Preferably, the length of the subsurface crack to be measured is greater than the wavelength of the excited surface wave.
Compared with the prior art, the invention has the beneficial effects that:
the method is simple to operate, the length of the subsurface crack can be obtained by one-time detection, the detection speed is high, and the detection precision is high. In addition, the invention is non-contact measurement, can be used for in-place detection in the machining process, does not need to take down a workpiece for detection, and improves the machining efficiency.
Drawings
FIG. 1 is a schematic diagram of the detection state of the present invention.
Fig. 2 is a diagram of ultrasonic signals detected by the laser vibrometer in the present invention.
In the figure, a workpiece 1, a subsurface crack 2, a pulse laser probe 3, and a laser vibrometer 4.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
The embodiment of the invention relates to a quantitative detection method for the length of a subsurface crack based on a laser excitation surface wave.
The basic principle of the subsurface crack length quantitative detection method based on the laser excitation surface wave is partially consistent with the content of the invention, and the method comprises the following specific steps:
1) the pulse laser probe 3 and the laser vibrometer probe 4 are placed on the same side of the subsurface crack 2 in the workpiece 1, and the laser vibrometer probe 3 is positioned between the pulse laser probe 4 and the subsurface crack 2.
2) The pulse laser probe 3 emits pulse laser to irradiate on the workpiece 2, the surface acoustic wave is excited on the surface of the workpiece, and a surface wave echo signal R reflected by the surface wave on the subsurface crack is measured by using a laser vibration meter.
3) Extracting the time t corresponding to the first trough of the surface wave echo signal RR1And time t corresponding to the second troughR2(ii) a The trough position is significantly different from other positions in other echo signals, and the technician can visually see in the ultrasonic signal diagram, as shown in fig. 2.
4) Using the obtained time tR1And tR2And calculating the length l of the subsurface crack. The calculation formula is as follows:
l＝vR(tR2-tR1)/2
wherein v isRThe propagation speed of the ultrasonic surface wave on the surface of the workpiece to be measured.
The subsurface crack length of a medium carbon steel block, which had a length of 100mm, a width of 50mm and a thickness of 5mm, was measured from the side of the workpiece using a Ginz VHX-600 optical microscope as a reference. And placing the steel block on a sample platform, exciting the surface wave and receiving the surface wave echo on the same side of the subsurface crack on the steel block by using a pulse laser probe and a laser vibration meter, and acquiring the arrival time of a first wave trough and a second wave trough of the surface wave echo for calculating the length of the subsurface crack.
Two subsurface cracks of 50.23 μm and 100.74 μm in length were measured by the above method, and the measurement results and their relative errors are shown in the following table:
as can be seen from the table, the method has high precision for the detection result of the length of the subsurface crack of the material, and the detection method is simple to operate, does not need scanning, only needs one-time detection at one point, and is very convenient and fast. Meanwhile, the method is non-contact detection, the workpiece does not need to be taken down from a machine tool and placed in a specific area for detection, and the method can be used for in-place detection in machining and improves machining efficiency.
Claims (6)
1. A subsurface crack length quantitative detection method based on laser excitation surface waves is characterized by comprising the following steps: the method comprises the following steps:
1) placing a pulse laser probe and a laser vibration meter probe on one side of the measured subsurface crack, wherein the laser vibration meter probe is positioned between the pulse laser probe and the subsurface crack;
2) the pulse laser probe emits pulse laser to irradiate on a workpiece, the surface acoustic wave is excited on the surface of the workpiece, and a surface wave echo signal R reflected by the surface wave on the subsurface crack is measured by using a laser vibration meter;
3) extracting the time t corresponding to the first trough of the surface wave echo signal RR1And the second trough of a waveCorresponding time tR2；
4) Calculating the length l-v of the subsurface crackR(tR2-tR1) 2; wherein v isRThe propagation speed of the ultrasonic surface wave on the surface of the workpiece to be measured.
2. The method of claim 1, wherein the sub-surface crack length is a function of a laser-excited surface wave, and wherein the method comprises: in the step 2), the excitation method of the ultrasonic surface wave is laser point source excitation, specifically, pulse laser emitted by a pulse laser probe is focused into point source laser through a convex lens, and the point source laser irradiates the surface of the workpiece and excites the ultrasonic surface wave.
3. The method of claim 1, wherein the sub-surface crack length is a function of a laser-excited surface wave, and wherein the method comprises: in the step 2), the excitation method of the ultrasonic surface wave is line source excitation, specifically, a pulse laser probe emits pulse laser, the pulse laser focuses the laser into line source laser through a cylindrical lens, irradiates the surface of the workpiece and excites the ultrasonic surface wave.
4. The method of claim 1, wherein the sub-surface crack length is a function of a laser-excited surface wave, and wherein the method comprises: the measured subsurface crack is a rectangular crack, and the line source laser emitted by the pulse laser probe is parallel to the axial direction of the subsurface crack.
5. The method of claim 1, wherein the sub-surface crack length is a function of a laser-excited surface wave, and wherein the method comprises: the propagation speed of the ultrasonic surface wave on the surface of the workpiece is obtained by searching an ultrasonic speed table.
6. The method of claim 1, wherein the sub-surface crack length is a function of a laser-excited surface wave, and wherein the method comprises: the length of the sub-surface crack being measured is greater than the wavelength of the excited surface wave.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115406384A (en) * | 2022-09-05 | 2022-11-29 | 天津大学 | Method for measuring opening width of crack on machined surface based on laser surface acoustic wave |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106017371A (en) * | 2016-06-29 | 2016-10-12 | 浙江大学 | Surface defect opening width measurement apparatus and method based on laser ultrasonic sound |
| CN107688051A (en) * | 2017-08-15 | 2018-02-13 | 浙江大学 | A kind of measuring method of the subsurface defect width based on Laser thermo-elastic generated surface acoustic waves |
| CN107747922A (en) * | 2017-09-30 | 2018-03-02 | 浙江大学 | A kind of sub-surface based on laser-ultrasound lacks the measuring method of buried depth |
| CN108169341A (en) * | 2017-12-29 | 2018-06-15 | 江苏共昌轧辊股份有限公司 | A kind of detection method of Heat Working Rolls roll surface micro-crack depth |
| CN113533504A (en) * | 2021-06-03 | 2021-10-22 | 杭州电子科技大学 | Sub-surface crack quantitative measurement method based on laser ultrasonic surface wave frequency domain parameters |
-
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106017371A (en) * | 2016-06-29 | 2016-10-12 | 浙江大学 | Surface defect opening width measurement apparatus and method based on laser ultrasonic sound |
| CN107688051A (en) * | 2017-08-15 | 2018-02-13 | 浙江大学 | A kind of measuring method of the subsurface defect width based on Laser thermo-elastic generated surface acoustic waves |
| CN107747922A (en) * | 2017-09-30 | 2018-03-02 | 浙江大学 | A kind of sub-surface based on laser-ultrasound lacks the measuring method of buried depth |
| CN108169341A (en) * | 2017-12-29 | 2018-06-15 | 江苏共昌轧辊股份有限公司 | A kind of detection method of Heat Working Rolls roll surface micro-crack depth |
| CN113533504A (en) * | 2021-06-03 | 2021-10-22 | 杭州电子科技大学 | Sub-surface crack quantitative measurement method based on laser ultrasonic surface wave frequency domain parameters |
Non-Patent Citations (4)
| Title |
|---|
| 冯若: "超声手册", 南京大学出版社, pages: 346 - 347 * |
| 合肥通用机械研究所五室探伤组: "对接焊缝超声波探伤中缺陷定量试验", 无损检测, 10 June 1979 (1979-06-10), pages 7 - 28 * |
| 徐春广等: "超声波检测基础", 31 March 2021, 北京理工大学出版社, pages: 122 * |
| 金长善: "超声工程", 31 July 1989, 哈尔滨工业大学出版社, pages: 346 - 347 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115406384A (en) * | 2022-09-05 | 2022-11-29 | 天津大学 | Method for measuring opening width of crack on machined surface based on laser surface acoustic wave |
| CN115406384B (en) * | 2022-09-05 | 2024-03-12 | 天津大学 | Machining surface crack opening width measuring method based on laser surface acoustic waves |
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