CN102253087A - Device and method for automatically measuring fatigue crack propagation velocity - Google Patents
Device and method for automatically measuring fatigue crack propagation velocity Download PDFInfo
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- CN102253087A CN102253087A CN 201110168553 CN201110168553A CN102253087A CN 102253087 A CN102253087 A CN 102253087A CN 201110168553 CN201110168553 CN 201110168553 CN 201110168553 A CN201110168553 A CN 201110168553A CN 102253087 A CN102253087 A CN 102253087A
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- 238000005259 measurement Methods 0.000 claims abstract description 52
- 239000013307 optical fiber Substances 0.000 claims abstract description 21
- 238000004590 computer program Methods 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims abstract description 15
- 238000012360 testing method Methods 0.000 claims abstract description 5
- 239000004020 conductor Substances 0.000 claims description 5
- 238000005336 cracking Methods 0.000 claims description 4
- 208000037656 Respiratory Sounds Diseases 0.000 claims description 3
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- 239000007769 metal material Substances 0.000 claims description 3
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention relates to a device and method for automatically measuring the fatigue crack propagation velocity, belonging to the technical field of material fatigue performance detection. The device provided by the invention comprises a break line (1) for marking fatigue crack propagation, a power supply or a light source, a wire or an optical fiber (2), a measuring device for measuring and recording current in the breakage line or the on-off of the optical fiber and a computer for converting the breakage measuring result of the breakage line into a computer program of the fatigue crack propagation velocity. The fatigue crack propagation parameters of a sample are obtained by measuring the condition that the breakage line is sequentially broken along with the fatigue crack propagation in the sample, and the fatigue crack propagation velocity is obtained through the processing of the computer. The device provided by the invention has the advantage of high accuracy, is simple and easy to operate and is suitable for fatigue crack propagation velocity measurement in corrosion media such as gas, liquid and the like and the fatigue crack propagation velocity measurement of samples, large-scale complicated test pieces or structures made of various materials such as metal, composite materials and the like.
Description
Technical field
The present invention relates to a kind of fatigue crack growth rate self-operated measuring unit and method, belong to fatigue of materials Performance Detection technical field.
Background technology
Fatigue failure is the one of the main reasons that causes engineering structure and mechanical failure.The purpose that fatigue crack growth rate is measured is the defective and the damage of obtaining in material, part or the structure, propagation law under the alternate load effect, so that the maintenance of given parts, structure and cycle in serviceable life, the security and the reliability of assurance parts or structure.
Existing fatigue crack growth rate measuring method has comprised ocular estimate, flexibility method, potential method etc.Ocular estimate is the most commonly used in these methods, but bears the fatigue load Oscillation Amplitude when big at sample, exists in the problem that is difficult to reading in the process of the test, must abort measure, and measuring accuracy is influenced by human factor; The corrosive medium transparency also directly influences the effect of this method in the corrosion fatigue, can't use ocular estimate that crack length is measured in the opaque medium; In labyrinth, personnel are difficult to observed position can't adopt ocular estimate, even by the auxiliary optical instrument, also will bring a series of problems such as illumination, space.Flexibility method and potential method are by reading the changing value conversion crack extending length of other physical quantity indirectly, but also exist restriction separately, at first both all need to demarcate before use crack extending length and survey relation between the physical quantity, and staking-out work itself is just comparatively complicated and loaded down with trivial details, and introduce error easily, reduce measuring accuracy; Secondly flexibility method also has certain requirement to the space, need tested position can hold the installation of extensometer on every side, may therefore be restricted in the use in labyrinth, in environment fatigue tests such as corrosion fatigue and high fatigue at low temperatures, also will increase the difficulty of experimental enviroment sealing; It is conductor that the current potential rule needs tested sample, is subject to the interference of various factors (as sample material electric conductivity, lead and sample link position, oxide and environmental impact etc.) and reduces measuring accuracy; Need additionally between sample and afterburner system, to take insulation measures; May cause the galvanochemistry influence when crack Propagation is measured in the water-bearing media.
Summary of the invention
In order to address the above problem, the invention provides a kind of fatigue crack growth rate self-operated measuring unit and method, precision is higher, simple, be applicable to that the fatigue crack growth rate in the corrosive mediums such as gas, liquid measures, also be applicable to the method that the fatigue crack growth rate of sample that multiple materials such as metal, compound substance make, large complicated testpieces or structure is measured.
The present invention adopts following technical scheme for solving its technical matters:
A kind of fatigue crack growth rate self-operated measuring unit, comprise the fracture line that are used to indicate crack Propagation, power supply or light source, lead or optical fiber, measure and the record fracture line in electric current or optical fiber break-make measurement mechanism and the fracture line measurement result that ruptures is converted into the computing machine of the computer program of fatigue crack growth rate, wherein, fracture line are enameled wire or optical fiber, stick on the sample, when the fracture line that are stuck are enameled wires, then enameled wire links to each other with the measurement mechanism of electric current in measurement and the record fracture line with power supply respectively by lead, and this measurement mechanism links to each other with the computing machine that measurement result that enameled wire is ruptured is converted into the computer program of fatigue crack growth rate by USB interface or serial ports; When the fracture line that are stuck are optical fiber, then optical fiber is connected with the measurement mechanism of light source with the optical fiber break-make respectively, and this measurement mechanism links to each other with the computing machine that optical fiber break-make measurement result is converted into the computer program of fatigue crack growth rate by USB interface or serial ports.
Described enameled wire is made up of conductor and insulation course two parts, and its material, shape and size are determined by tested sample.
The measurement mechanism of electric current or light break-make is made up of serial ports or USB interface that circuit board, programmable chip link to each other with computing machine in described measurement and the record fracture line.
The measuring method of described fatigue crack growth rate self-operated measuring unit comprises the steps:
Step 4, measure and note time of every fracture line fracture by the chip in the measurement mechanism;
Step 5, measurement mechanism are sent to measurement result in the computing machine that the computer program that is converted into fatigue crack growth rate has been installed by USB interface or serial ports;
Step 6, the computing machine by computer program are converted into crack length and time relation with rupture order and time relation of fracture line;
Step 7, with reference to the data processing method that GB/T6398-2000 " metal material fatigue crack growth rate test method " recommends, in computer program, crack length and time relation are converted into fatigue crack growth rate.
Beneficial effect of the present invention is as follows:
1, realized that whole-course automation is measured and directly exported the fatigue crack growth rate result, simplified the fatigue crack growth rate surveying work greatly.
2, the present invention is simple, and all component price is relatively low, obtain simple, and installation cost is low; The diameter of fracture line is little and consistent, and the current switching time of measuring by chip can be as accurate as millisecond, so the measurement result precision is higher.
3, under the prerequisite of the fracture line consistent, can be applied to various materials (comprising nonconducting compound substance), and not be subjected to extraneous factor and artificial factor such as medium and temperature with the measured material fracture strength.
4, be subjected to the restriction in space very little, the space that only needs to hold fracture line gets final product, and can be applicable to be subjected to space constraint can't use the position of ocular estimate or equivalent method observation and layout extensometer.
Description of drawings
The structural representation of Fig. 1 fatigue crack growth rate self-operated measuring unit, Fig. 1 (a) is for adopting the apparatus structure synoptic diagram of enameled wire as fracture line, and Fig. 1 (b) is for adopting the apparatus structure synoptic diagram of optical fiber as fracture line, and wherein, 1 is fracture line; 2 is lead; 3 is sample.
The synoptic diagram that Fig. 2 ruptures with crack Propagation for fracture line, wherein, 4 is fatigue crack.
Embodiment
Below in conjunction with accompanying drawing the invention is described in further details:
The present invention adopts device as shown in Figure 1 to implement the fatigue crack growth rate method for automatic measurement, when fracture line 1 adopt enameled wire, this device comprises the enameled wire 1 that is used for indicating crack Propagation, lead 2, power supply, measurement and writes down the measurement mechanism of fracture line current switching and the enameled wire measurement result that ruptures is converted into the computing machine of the computer program of fatigue crack growth rate as Fig. 1 (a) shown in.Wherein, enameled wire 1 links to each other with measurement mechanism with power supply by lead 2, and measurement mechanism links to each other the enameled wire computing machine that measurement result is converted into the computer program of fatigue crack growth rate that ruptures with having installed by USB interface or serial ports.
It is as follows to use this device to carry out the step that fatigue crack growth rate measures, and is that enameled wire is an example with fracture line 1:
Step 4, measure and note time of every fracture line fracture by the chip in the measurement mechanism;
Step 5, measurement mechanism are sent to measurement result in the computing machine that the computer program that is converted into fatigue crack growth rate has been installed by USB interface or serial ports;
Step 6, rupture order and time relation of fracture line is converted into crack length and time relation by computer program
Step 7, with reference to the data processing method that GB/T6398-2000 " metal material fatigue crack growth rate test method " recommends, in computer program, crack length and time relation are converted into fatigue crack growth rate.
In the said apparatus, described fracture line 1 can be selected enameled wire, and its conductor material can be selected the fracture toughness conductor close with measured material, preferred aluminium, copper, alloy; Insulating material according to operating ambient temperature, humidity, whether have factors such as corrosivity and choose preferred polyester and modified poly ester, polyester-imide/polyamide composite bed, polyester-imide/polyamidoimide composite bed.Fracture line 1 also can be selected optical fiber, at this moment, make power supply into light source, and light source need not link to each other with measurement mechanism again, and lead 2 changes optical fiber into, increase photoelectric induction device in the measurement mechanism and get final product.
As shown in Figure 2, fracture line 1 are pasted on sample 3 surface fatigue risk of crack districts, along with FATIGUE CRACK GROWTH, the fracture line 1 that are positioned at crack tip are elongated along with the specimen surface cracking and rupture successively, the transmission of electric current/light is interrupted immediately in the fracture line 1, measurement mechanism can convert through computer program by the concrete time of measuring and writing down electric current in each fracture line 1/light break-make, thereby obtained fatigue crack growth rate.
The measuring process that has fatigue crack growth rate method for automatic measurement of the present invention realizes robotization, device is easy to design and manufacturing, cost is low, precision is high, be not subject to extraneous factor and interference from human factor, be applicable to sample, structure and the parts advantages such as measurement in various environment that different materials is made, in suitable laboratory and the engineering site to the measurement of all kinds of samples, parts and structural fatigue crack growth rate.
Claims (4)
1. fatigue crack growth rate self-operated measuring unit, it is characterized in that comprising the fracture line (1) that are used to indicate crack Propagation, power supply or light source, lead or optical fiber (2), measure and the record fracture line in electric current or optical fiber break-make measurement mechanism and the fracture line measurement result that ruptures is converted into the computing machine of the computer program of fatigue crack growth rate, wherein, fracture line (1) are enameled wire or optical fiber, stick on the sample (3), when the fracture line that are stuck (1) are enameled wires, then enameled wire (1) links to each other with the measurement mechanism of electric current in measurement and the record fracture line with power supply respectively by lead (2), and this measurement mechanism links to each other with the computing machine that measurement result that enameled wire is ruptured is converted into the computer program of fatigue crack growth rate by USB interface or serial ports; When the fracture line that are stuck (1) are optical fiber, then optical fiber is connected with the measurement mechanism of light source with the optical fiber break-make respectively, and this measurement mechanism links to each other with the computing machine that optical fiber break-make measurement result is converted into the computer program of fatigue crack growth rate by USB interface or serial ports.
2. fatigue crack growth rate self-operated measuring unit according to claim 1 is characterized in that, described enameled wire is made up of conductor and insulation course two parts, and its material, shape and size are determined by tested sample.
3. fatigue crack growth rate self-operated measuring unit according to claim 1 is characterized in that, the measurement mechanism of electric current or light break-make is made up of serial ports or USB interface that circuit board, programmable chip link to each other with computing machine in described measurement and the record fracture line.
4. an application rights requires the measuring method of 1 described fatigue crack growth rate self-operated measuring unit, it is characterized in that, comprises the steps:
Step 1, fracture line (1) are sticked in tested sample (3) or the structure zone that easily produces fatigue crack;
Step 2, the fracture line (1) that paste are connected with measurement mechanism with power supply or light source respectively;
Step 3, beginning torture test apply alternate load to sample (3) or structure, and along with the germinating and the expansion of crackle, the fracture line (1) that stick on sample (3) or body structure surface rupture along with its surface below cracking;
Step 4, measure and note time of every fracture line fracture by the chip in the measurement mechanism;
Step 5, measurement mechanism are sent to measurement result in the computing machine that the computer program that is converted into fatigue crack growth rate has been installed by USB interface or serial ports;
Step 6, the computing machine by computer program are converted into crack length and time relation with rupture order and time relation of fracture line;
Step 7, with reference to the data processing method that GB/T6398-2000 " metal material fatigue crack growth rate test method " recommends, in computer program, crack length and time relation are converted into fatigue crack growth rate.
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| CN 201110168553 CN102253087A (en) | 2011-06-22 | 2011-06-22 | Device and method for automatically measuring fatigue crack propagation velocity |
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| CN 201110168553 CN102253087A (en) | 2011-06-22 | 2011-06-22 | Device and method for automatically measuring fatigue crack propagation velocity |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565140A (en) * | 2012-02-20 | 2012-07-11 | 南京航空航天大学 | Method for measuring fatigue crack growth rate on basis of potential method |
| CN105606617A (en) * | 2016-01-06 | 2016-05-25 | 武汉理工大学 | Device and method for measuring fatigue crack propagation rule of CFRP reinforced steel structure |
| CN106248682A (en) * | 2016-07-21 | 2016-12-21 | 大连海事大学 | A kind of miter gate's crackle on-line detecting system and detection method thereof |
| CN106596729A (en) * | 2016-12-22 | 2017-04-26 | 北京航空航天大学 | Method for monitoring fatigue crack propagation and evaluating hydrogen brittleness of 2.25Cr-1Mo steel based on sound emission |
| CN109556958A (en) * | 2018-12-07 | 2019-04-02 | 武汉科技大学 | A kind of test method of simple check line crack starter location and spreading rate at first |
| JP2020139814A (en) * | 2019-02-27 | 2020-09-03 | 三菱重工業株式会社 | Crack sensor system |
| CN115791460A (en) * | 2022-11-18 | 2023-03-14 | 中国矿业大学 | Sensor for propagation speed of blasting crack in rock material and testing method thereof |
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| CN1869640A (en) * | 2006-05-24 | 2006-11-29 | 浙江大学 | Method for investigating fatigue crack expansion |
| CN101544064A (en) * | 2009-05-08 | 2009-09-30 | 南京航空航天大学 | Intelligent structure self-healing method and health monitoring system based on light repairing technology |
| CN101936955A (en) * | 2010-08-06 | 2011-01-05 | 宁波大学 | Device and method for measuring propagation velocity of dynamic crack |
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2011
- 2011-06-22 CN CN 201110168553 patent/CN102253087A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1869640A (en) * | 2006-05-24 | 2006-11-29 | 浙江大学 | Method for investigating fatigue crack expansion |
| CN101544064A (en) * | 2009-05-08 | 2009-09-30 | 南京航空航天大学 | Intelligent structure self-healing method and health monitoring system based on light repairing technology |
| CN101936955A (en) * | 2010-08-06 | 2011-01-05 | 宁波大学 | Device and method for measuring propagation velocity of dynamic crack |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565140A (en) * | 2012-02-20 | 2012-07-11 | 南京航空航天大学 | Method for measuring fatigue crack growth rate on basis of potential method |
| CN105606617A (en) * | 2016-01-06 | 2016-05-25 | 武汉理工大学 | Device and method for measuring fatigue crack propagation rule of CFRP reinforced steel structure |
| CN106248682A (en) * | 2016-07-21 | 2016-12-21 | 大连海事大学 | A kind of miter gate's crackle on-line detecting system and detection method thereof |
| CN106248682B (en) * | 2016-07-21 | 2018-09-25 | 大连海事大学 | A kind of miter gate's crackle on-line detecting system and its detection method |
| CN106596729A (en) * | 2016-12-22 | 2017-04-26 | 北京航空航天大学 | Method for monitoring fatigue crack propagation and evaluating hydrogen brittleness of 2.25Cr-1Mo steel based on sound emission |
| CN109556958A (en) * | 2018-12-07 | 2019-04-02 | 武汉科技大学 | A kind of test method of simple check line crack starter location and spreading rate at first |
| JP2020139814A (en) * | 2019-02-27 | 2020-09-03 | 三菱重工業株式会社 | Crack sensor system |
| WO2020174760A1 (en) * | 2019-02-27 | 2020-09-03 | 三菱重工業株式会社 | Crack sensor system |
| JP7194046B2 (en) | 2019-02-27 | 2022-12-21 | 三菱重工業株式会社 | crack sensor system |
| CN115791460A (en) * | 2022-11-18 | 2023-03-14 | 中国矿业大学 | Sensor for propagation speed of blasting crack in rock material and testing method thereof |
| CN115791460B (en) * | 2022-11-18 | 2023-08-22 | 中国矿业大学 | Sensor for crack propagation speed of internal blasting of rock material and testing method thereof |
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Application publication date: 20111123 |