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CN102679931A - Novel method for measuring fatigue crack propagation length in situ - Google Patents

Novel method for measuring fatigue crack propagation length in situ Download PDF

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CN102679931A
CN102679931A CN2012101423697A CN201210142369A CN102679931A CN 102679931 A CN102679931 A CN 102679931A CN 2012101423697 A CN2012101423697 A CN 2012101423697A CN 201210142369 A CN201210142369 A CN 201210142369A CN 102679931 A CN102679931 A CN 102679931A
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fatigue
crack
length
fatigue crack
metallographic microscope
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CN102679931B (en
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刘鹏
刘霞
赵炳戈
高玉来
翟启杰
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University of Shanghai for Science and Technology
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Abstract

本发明涉及一种原位测量疲劳裂纹扩展长度的方法。本发明的优点和特征在于：a)将100倍金相显微镜、容栅传感器、信号处理系统、CCD摄像头、计算机等进行集成，实现了数据采集和处理一体化，实现了原位、实时测量疲劳裂纹扩展长度；b)解决了通常采用的普通读数法测量耗时长、操作繁琐、容易对后续测量产生不利影响的缺点；c)采用容栅传感器，将获取的位移信号转换成电信号，通过信号传输和转换设备得到最终的裂纹长度，实现了半自动测量；d)将CCD摄像头通过金相显微镜采集到的实时图像传递到计算机，实现了整个测试过程的可视化，解决了传统测量只能观察结果，无法直接观测过程的难题。

The invention relates to a method for measuring the extension length of fatigue cracks in situ. The advantages and features of the present invention are: a) 100 times metallographic microscope, capacitive sensor, signal processing system, CCD camera, computer, etc. are integrated to realize the integration of data acquisition and processing, and realize the in-situ and real-time measurement of fatigue Crack growth length; b) Solve the shortcomings of the common reading method that usually takes a long time to measure, cumbersome to operate, and easily have adverse effects on subsequent measurements; c) Use a capacitive sensor to convert the acquired displacement signal into an electrical signal, and pass the signal The transmission and conversion equipment obtains the final crack length, which realizes semi-automatic measurement; d) transmits the real-time image collected by the CCD camera through the metallographic microscope to the computer, realizing the visualization of the entire testing process, and solving the problem that traditional measurement can only observe the results, The problem of not being able to directly observe the process.

Description

The new method of in site measurement crack Propagation length
Technical field
The present invention relates to a kind of can be in the fatigue property test process new method of in site measurement crack Propagation length, can realize that fatigue classifies the real-time online measuring of extension length as.The invention belongs to the Measurement of Material Mechanical Performance field.
Background technology
Fatigue is meant material, part and member under CYCLIC LOADING, puts the permanent damage that produces the part at certain point or some, and after certain cycle index, forms crackle or make crackle further expand the phenomenon that ruptures up to fully.Citation (the American Society for Testing and Materials of American Society for Testing and Materials; ASTM) definition of being done in (EZ06-72) in " standard definition of the relational term of torture test and data statistic analysis ": bear at certain point or some point and to scratch dynamic stress; And abundant circulation scratch action with after form crackle or when rupturing fully; The evolution that the local permanent structure that is taken place in the material changes is called " fatigue ".
The phenomenon destroyed takes place under far below the cyclic loading effect of its strength degree in material, is called fatigure failure.Fatigure failure mainly contains following characteristic:
1) only bear cyclic loading at material and do the time spent, fatigue just can take place.
2) fatigue is one " evolution ", and this process occurred in a period of time." formation crackle " and " fracture " are the results of the continuous damage accumulation that forms in this evolution.
3) fatigue takes place in certain regional area usually, rather than is controlled by total or member.
4) fatigue process is the accumulation that the inside configuration permanent change causes damage.
The various aspects of engineering in modern times, critical part and member are worked under the effect of cyclic loading mostly, and fatigure failure is its main form of invalidation.Along with development of modern industry, the requirement of the fatigue behaviour of material is also progressively improved, so the fatigure failure mechanism of research material, thereby seek to improve the method for fatigue of materials performance, have obvious social and economic worth.
At present, the fatigue of materials drag index that adopts usually has fatigue strength, overload persistence value, tired notch sensitivity, fatigue crack growth rate and threshold in fatigue crack propagation etc.And the index that wherein adopts maximum evaluating material fatigue behaviours is fatigue crack growth rate (da/dN) and threshold in fatigue crack propagation (Δ K Th), Δ K especially ThBecome and weighed material and the most important index of vitals fatigue behaviour.According to the relevant regulations among the GB/T 6398-2000, the definition fatigue crack growth rate equals 1 * 10 -7The pairing stress intensity factor range value of mm/cycle is Δ K Th
The factor of tired threshold value that influences material is a lot, below with regard to the associated arguments that possibly relate in the testing fatigue process do brief account (with specified standard compact tension specimen among the GB/T6398-2000 (Compact Tension, CT) sample is an example):
1) period N: power round-robin number of times.
2) fatigue crack growth rate da/dN: the FATIGUE CRACK GROWTH amount of power circulation primary is expressed as the function of fatigue crack tip stress intensity factor Δ K in the GB.
3) stress strength factor K: the value of crack tip near zone elastic stress field strength.
4) crack length a: the straight leading edge crack length suitable with actual crack.For the CT sample, a begins to calculate from adding the line of force.
5) maximum load P Max: the maximum algebraic value of cyclic force.
6) minimum load P Min: the minimal algebra value of cyclic force.
7) power value range delta P: the difference between maximum and the minimum force, i.e. Δ P=P Max-P Min
8) stress ratio R: the ratio of minimum force and maximum, force, i.e. R=P Min/ P Max
9) maximum stress intensity factor K Max: corresponding to the stress intensity factor of maximum, force, and change along with the growth of crack length.
10) maximum stress intensity factor K Min: corresponding to the stress intensity factor of minimum force.
11) stress intensity factor range Δ K: maximum is poor with the minimum stress-intensity factor value, i.e. Δ K=K Max-K Min
For the CT sample,
Figure 2012101423697100002DEST_PATH_IMAGE002
（1）
In the formula: α=a/W (W is the distance of line of force to CT sample edge); B is the thickness of CT sample.
Can be known by formula (1): in whole test process, the accurate measurement of crack Propagation length is one of key factor.The method of the measurement fatigue crack that is adopted at present has common method of reading, strain gauge method, equivalent potential method etc., and is wherein higher relatively with common method of reading precision especially.
The operation steps of common method of reading is to measure its length under the metaloscope behind the circulation several times fatigue testing specimen being unloaded from fatigue tester and it is positioned over.This precision of method is higher, but has following defective:
Need shed load when 1) measuring crack extending length, the dismounting sample is measured its crack length at microscopically; Need reinstall sample after measurement finishes, reload.The whole operation process is loaded down with trivial details, wastes time and energy, and possibly cause the clamping of CT sample and medium parameter is changed, and influences the repeatability of test result.
2) dismounting sample process has been interrupted the effect of load, for follow-up fatigue crack growth rate da/dN bigger influence is arranged, and causes measured da/dN to depart from actual value.
3) rely on the da/dN value of upper level to estimate required period of carrying out, can't observe real-time crack extending length, reduced conventional efficient.In addition, the whole operation process requires than higher operating personnel's experience.
Therefore, seek more accurate measuring method and help to improve fatigue of materials threshold value test accuracy and repeatability undoubtedly.
The present invention is directed to fatigue crack and test the deficiency of common method of reading; Propose to adopt the combination of equipment such as metaloscope and capacitor grid transducer; Reaching the degree of accuracy that improves the crack Propagation linear measure longimetry and to realize, and concrete embodiment has been proposed to the visual purpose of Fatigue Cracks Propagation.
The inventor adopt fatigue crack+in site measurement (fatigue crack+in-situ measurement) as keyword retrieval United States Patent (USP) digest (USPTO), European patent digest (EP-PCT), " Chinese patent Information Network " and " State Intellectual Property Office of the People's Republic of China's patent retrieval " are not found patent family.
Summary of the invention
The new method and the device thereof that the purpose of this invention is to provide a kind of in site measurement crack Propagation length.More particularly; The purpose of this invention is to provide a kind of can be in the testing fatigue process method of in site measurement fatigue crack length and Real Time Observation crack Propagation; Thereby can more accurately confirm various fatigue stress indexs; So that weigh the fatigue behaviour of various materials under the different technology conditions better, this design and manufacturing to a lot of important components has realistic meaning.
The new method of a kind of in site measurement crack Propagation of the present invention length can be used in real time, the mensuration of crack Propagation length when accurately measuring fatigue property test; The method is characterized in that; Adopt metaloscope and electric charge coupling (Charge Couple Device; CCD) camera; Real-time follow-up fatigue crack tip extensions path is transformed into mechanical displacement the phase changing capacity of electric signal immediately through capacitor grid transducer, obtains accurate fatigue crack length after handling through metering circuit again; Its concise and to the point measuring method is following: (a) be clamped on the fatigue tester with anchor clamps with through the standard CT sample that polishes, measuring equipment base and support are positioned over the appropriate location; (b) regulate the location tooth bar, make the object lens alignment machine of metaloscope process prefabricated crack tip, in metaloscope, observe the centermost (intersection point of horizontal and vertical scale line) of machine work crack tip in the visual field.Crack length reading on the display is returned to zero; (c) connect the CCD camera, make on display, can clearly show the specimen surface image; (d) start fatigue tester, through the position of adjustment tooth bar conversion metaloscope, make the tip of fatigue crack be in all the time the CCD camera collection to picture in; Through the crack length in the photo of gathering in reading on the electronic display and the metaloscope, accurately confirm the length of true fatigue crack; Simultaneously, can also according to the CCD camera collection to photo analyze the reason that skew takes place for direction of crack propagation in its crack propagation process; The microstructure to sample in conjunction with behind the testing fatigue is carried out optical microscope and sem observation, can further analyze the fatigue fracture mechanism of the material of measuring and monitoring the growth of standing timber.
The used isolated plant of method of a kind of in site measurement crack Propagation of the present invention length is characterized in that including: standard CT sample, metaloscope, CCD camera, bradyseism base, capacitor grid transducer, anchor clamps, pin, data transmission system, positioning knob, location tooth bar and computing machine; The arrangement relation of each parts is following: standard CT sample, pin are connected on the fatigue tester with anchor clamps, and metaloscope and location tooth bar are synchronous, are directly installed on the bradyseism base, through its position of positioning knob adjustment; The CCD camera is connected on the metaloscope, the data that collect is passed on the computing machine through data transmission system handle, and obtains final fatigue crack length and fatigue crack surface topography photo.
Characteristics of the present invention
Equipment such as the inventive method joining gold phase microscope, location tooth bar, capacitor grid transducer, signal translating system, CCD camera, computing machine; The new method of in site measurement fatigue crack length has been proposed; Convert displacement signal to electric signal through capacitor grid transducer, realized the in site measurement of Fatigue Cracks Propagation in the whole fatigue experiment process and visual.Not only the fatigue crack length of any time be can accurately measure, and can instant observation and collection be carried out the fatigue crack tip extensions path.
The principle of work of in site measurement method is through 100 times of metaloscopes (through synchronous location tooth bar adjusting position) and CCD camera collection crack tip image, and the picture that collects is connected on the computing machine, realizes the visual of Fatigue Cracks Propagation.Simultaneously, the capacitor grid transducer synchronous with metaloscope converts displacement signal to electric signal, becomes digital signal through signal converter again, at last through obtaining fatigue crack length after the Computer Processing.
Description of drawings
Fig. 1 is the equipment synoptic diagram of in site measurement crack Propagation length.This equipment mainly is made up of metaloscope, capacitor grid transducer, CCD camera, location tooth bar, data acquisition and transmission system, bradyseism base etc.
Fig. 2 is the side view of the equipment of home position observation crack Propagation length.
Fig. 3 is the standard CT assay maps, adopts the method for line cutting to process according to the regulation of the size in the GB (GB/T 6398-2000).
Fig. 4 is the variation relation figure of stress intensity factor range Δ K of fatigue crack growth rate da/dN and the crack tip of material under each stress ratio of certain material.
Fig. 5 is the fitted figure of lg (da/dN) and lg Δ K under each stress ratio of this material.
Fig. 6 is this material crack expansion threshold value Δ K ThGraph of a relation with the stress ratio variation.
Embodiment
Below in conjunction with embodiment the present invention is elaborated:
Embodiment one
Concrete steps are following:
Threshold in fatigue crack propagation (Δ K Th) test adopt the K method of the falling measurement of stipulating among ASTM E647-08 and the GB/T 6398-2000.Detailed measuring process is following:
1) a certain size blank of intercepting from the test material goes out to meet specified standard CT and unit clamp among the GB/T 6398-2000 with the line cutting processing, and the concrete size of CT sample is seen Fig. 3.
2) anchor clamps that process are contained on the load fatigue tester, the distance between the adjustment fatigue tester pull bar places anchor clamps to clamp on the standard CT sample to correct position, and the acting force that the warranty test machine loads on the CT sample has good centering.
3) base with measurement mechanism is placed on suitable position with propping up, and makes micro objective over against the CT specimen surface, can clearly observe specimen surface in focusing knob to the eyepiece of adjusting metaloscope.
4) regulate the location tooth bar, make in the display the most advanced and sophisticated of display machines processing crackle clearly and it is adjusted to the center of visual field, and will this moment crack length zeroing in the display.
5) choose suitable stress ratio R and load p, carry out precrack.When the reading on the display is about 3 mm, stop to load the prefabricated end of crackle.Accurately write down fatigue crack length a and cycle index N.
6) adopt certain specific R of design in advance and choose suitable maximum load P Max, keep R invariable, reduce load step by step and carry out data acquisition, with the numerical value of a and N under each grade of new method accurate recording acting force of in site measurement crack Propagation length of the present invention, and calculate Δ K, K at this moment according to formula (1) MaxDeng parameter.In falling the process of carrying, make expansion increment Delta a under every grade of power greater than upper level K MaxThe plastic zone γ that (maximum stress intensity factor) is corresponding y4 ~ 6 times, up to average crack spreading rate Δ a/ Δ N near 1 * 10 -7During mm/cycle, fall the K experiment and finish.For the variation that guarantees image data in allowed band, every grade the amplitude of carrying of falling is no more than 10%, when da/dN 10 -6~ 10 -7In the time of in the mm/cycle interval, can suitably reduce to fall the amplitude of carrying to guarantee to have enough fitting data points.
According to the pairs formula:
Figure 2012101423697100002DEST_PATH_IMAGE004
（2）
Wherein, C with m is and the relevant constant of the character of material own.
Do can get lg (da/dN)=mlg Δ K+lgC after logarithm is handled, hence one can see that, and lg (da/dN) and lg Δ K are linear.According to da/dN 10 -6~ 10 -7The da/dN that obtains in the mm/cycle interval-Δ K corresponding relation makes its corresponding point in lg (da/dN)-lg Δ K coordinate system, the method through linear fit obtains C and m, carries it in the formula (2), and makes da/dN=1 * 10 -7Mm/cycle obtains Δ K, promptly desired threshold in fatigue crack propagation Δ K Th

Claims (2)

1.一种原位测量疲劳裂纹扩展长度的新方法，可用于实时、精确地测量疲劳性能测试时疲劳裂纹扩展长度的测定，该方法的特征在于，采用金相显微镜和电荷耦合（Charge Couple Device, CCD）摄像头，实时跟踪疲劳裂纹尖端扩展路径，通过容栅传感器即时将机械位移量转变成电信号的相位变化量，再通过测量电路处理后得到精确的疲劳裂纹长度；其简要的测量方法如下：（a）将夹具和经过抛光的标准CT试样装夹于疲劳试验机上，将测量设备底座和支架放置于适当位置；（b）调节定位齿条，使得金相显微镜的物镜对准机加工预制的裂纹尖端，在金相显微镜中观察到机加工裂纹尖端在视场的正中心(横向和纵向标尺线的交点)；将显示器上的裂纹长度读数调零；（c）连接CCD摄像头，使得在显示器上能够清晰地显示试样表面图像；（d）启动疲劳试验机，通过调整齿条变换金相显微镜的位置，使得疲劳裂纹的尖端始终处于CCD摄像头采集到的图片中；通过电子显示屏上的读数和金相显微镜中采集的照片中的裂纹长度，精确地确定真实疲劳裂纹的长度；同时，还可以根据CCD摄像头采集到的照片分析其裂纹扩展过程中裂纹扩展方向发生偏移的原因；结合疲劳测试后的对试样的显微组织进行光学显微镜和扫描电子显微镜观察，可进一步分析所测材料的疲劳断裂机理。 1. A new method for measuring the fatigue crack growth length in situ, which can be used to measure the fatigue crack growth length in real time and accurately during the fatigue performance test. The method is characterized in that a metallographic microscope and a charge coupled device are used , CCD) camera to track the propagation path of the fatigue crack tip in real time, and convert the mechanical displacement into the phase change of the electrical signal immediately through the capacitive sensor, and then obtain the accurate fatigue crack length after processing by the measurement circuit; the brief measurement method is as follows : (a) Clamp the fixture and the polished standard CT sample on the fatigue testing machine, and place the base and bracket of the measuring equipment in an appropriate position; (b) Adjust the positioning rack so that the objective lens of the metallographic microscope is aligned with the machined The prefabricated crack tip is observed in the metallographic microscope at the center of the field of view (the intersection of the horizontal and vertical scale lines); the crack length reading on the display is zeroed; (c) the CCD camera is connected so that The surface image of the sample can be clearly displayed on the monitor; (d) start the fatigue testing machine, and change the position of the metallographic microscope by adjusting the rack, so that the tip of the fatigue crack is always in the picture collected by the CCD camera; through the electronic display The readings on the computer and the crack length in the photos collected by the metallographic microscope can accurately determine the length of the real fatigue crack; at the same time, it can also analyze the reason for the deviation of the crack growth direction during the crack growth process based on the photos collected by the CCD camera Combining the optical microscope and scanning electron microscope observation of the microstructure of the sample after the fatigue test, the fatigue fracture mechanism of the tested material can be further analyzed. 2.一种原位测量疲劳裂纹扩展长度的方法所用的专用装置，其特征是包括有：标准CT试样（1）、金相显微镜（2）、CCD摄像头（3）、缓震底座（4）、容栅传感器（5）、夹具（6）、销钉（7）、数据传输系统（8）、调位旋钮（9）、定位齿条（10）、计算机（11）；各部件的布置关系如下：标准CT试样、销钉用夹具连接到疲劳试验机上，而金相显微镜和定位齿条同步，直接安装在缓震底座上，通过定位旋钮调整其位置；CCD摄像头连接于金相显微镜上，将采集到的数据通过数据传输系统传到计算机上进行处理，得到最终的疲劳裂纹长度以及疲劳裂纹表面形貌照片。 2. A special device for in-situ measurement of fatigue crack growth length, characterized in that it includes: standard CT sample (1), metallographic microscope (2), CCD camera (3), cushioning base (4 ), capacitive sensor (5), fixture (6), pin (7), data transmission system (8), adjustment knob (9), positioning rack (10), computer (11); the arrangement relationship of each component As follows: Standard CT samples and pins are connected to the fatigue testing machine with fixtures, while the metallographic microscope is synchronized with the positioning rack, directly installed on the cushioning base, and its position is adjusted by the positioning knob; the CCD camera is connected to the metallographic microscope. The collected data is transmitted to the computer through the data transmission system for processing, and the final fatigue crack length and fatigue crack surface topography photos are obtained.
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103954487A (en) * 2014-04-28 2014-07-30 浙江大学 Method for preparing in-situ tensile sample for transmission electron microscope
CN104833598A (en) * 2015-05-05 2015-08-12 上海工程技术大学 Observation system for fatigue crack expansion of metal material
CN104865139A (en) * 2015-06-01 2015-08-26 南昌航空大学 Fatigue crack three-dimensional expansion comparative analysis method for off-line CT detection condition
CN105334237A (en) * 2015-11-10 2016-02-17 西南交通大学 Fatigue testing machine and testing method capable of synchronously radiating light source for in-site imaging
CN105352968A (en) * 2015-11-19 2016-02-24 中国航空工业集团公司北京航空材料研究院 Method for measuring fatigue crack tip stress strength factor of organic glass
CN112964583A (en) * 2021-02-03 2021-06-15 天津大学 Method for detecting and representing crack evolution based on electric signal induction fatigue system
JP2021156778A (en) * 2020-03-27 2021-10-07 川崎重工業株式会社 Jig for fatigue sensor and attachment therefor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4878114A (en) * 1988-05-10 1989-10-31 University Of Windsor Method and apparatus for assessing surface roughness
CN1983023A (en) * 2004-12-13 2007-06-20 Hoya株式会社 Method and system for detecting corrugation defect and manufacturing method of photomask
CN101358930A (en) * 2008-10-09 2009-02-04 中国航空工业第一集团公司北京航空材料研究院 A test method for corrosion solution fatigue small crack growth
CN101441154A (en) * 2008-12-23 2009-05-27 华东理工大学 High precision microscopic fatigue tester
CN101666740A (en) * 2009-09-28 2010-03-10 清华大学 Measuring device of micro scale dynamic response

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4878114A (en) * 1988-05-10 1989-10-31 University Of Windsor Method and apparatus for assessing surface roughness
CN1983023A (en) * 2004-12-13 2007-06-20 Hoya株式会社 Method and system for detecting corrugation defect and manufacturing method of photomask
CN101358930A (en) * 2008-10-09 2009-02-04 中国航空工业第一集团公司北京航空材料研究院 A test method for corrosion solution fatigue small crack growth
CN101441154A (en) * 2008-12-23 2009-05-27 华东理工大学 High precision microscopic fatigue tester
CN101666740A (en) * 2009-09-28 2010-03-10 清华大学 Measuring device of micro scale dynamic response

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
潘典三: "研究型金相显微镜及其进展", 《武汉工学院学报》 *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103954487A (en) * 2014-04-28 2014-07-30 浙江大学 Method for preparing in-situ tensile sample for transmission electron microscope
CN104833598A (en) * 2015-05-05 2015-08-12 上海工程技术大学 Observation system for fatigue crack expansion of metal material
CN104865139A (en) * 2015-06-01 2015-08-26 南昌航空大学 Fatigue crack three-dimensional expansion comparative analysis method for off-line CT detection condition
CN104865139B (en) * 2015-06-01 2017-09-01 南昌航空大学 A comparative analysis method for three-dimensional fatigue crack growth under the condition of off-line CT detection
CN105334237A (en) * 2015-11-10 2016-02-17 西南交通大学 Fatigue testing machine and testing method capable of synchronously radiating light source for in-site imaging
CN105334237B (en) * 2015-11-10 2018-05-18 西南交通大学 The fatigue tester and test method of in situ imaging can be carried out with synchrotron radiation light source
CN105352968A (en) * 2015-11-19 2016-02-24 中国航空工业集团公司北京航空材料研究院 Method for measuring fatigue crack tip stress strength factor of organic glass
JP2021156778A (en) * 2020-03-27 2021-10-07 川崎重工業株式会社 Jig for fatigue sensor and attachment therefor
CN112964583A (en) * 2021-02-03 2021-06-15 天津大学 Method for detecting and representing crack evolution based on electric signal induction fatigue system

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