CN104406867A - Fatigue crack propagation test method based on replication and small time scale life forecast - Google Patents
Fatigue crack propagation test method based on replication and small time scale life forecast Download PDFInfo
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Abstract
The invention discloses a fatigue crack propagation test method based on replication and small time scale life forecast. The method comprises the following steps: step 1, according to a theory of small time scale, on a sample, selecting five loading periods from a prefabricated gap position to the critical growth position of a crack, and respectively and symmetrically selecting ten test points in the loading and unloading processes of each loading period; step 2, obtaining the microtopography of each test point with a first replication method, putting the replicated sample under a scanning electron microscope for morphological observation and image collecting; when crack growth increment cannot be seen clearly under the scanning electron microscope, that the second replication of the step 3 needs to be conducted; step 3, putting the sample after being replicated for twice under a transmission electron microscope for morphological observation and image collecting, and measuring the fatigue crack growth increment and CTOD according to pictures.
Description
Technical field
The present invention relates to a kind of investigating fatigue crack expansion method, be specifically related to a kind of investigating fatigue crack expansion method towards replica and small time scales life prediction, be applicable to the hardware being in plane strain state.
Background technology
The problem of fatigue damage research caused about fatigue crack always is hot issue, and fatigue life prediction is one of them huge challenge.Traditional fatigue damage method is all the analytical approach based on cyclic loading, is according to S-N curve the earliest, because the method time scale is relatively large, therefore is generally used for the final fatigue lifetime describing material or structure.The mainstream research method of current fatigue lifetime is the model based on relation (Paris formula) between the average each cycle rate of rise of fatigue crack and stress intensity amplitude, reduce the spatial and temporal scales of Tiredness model largely, but its minimum time yardstick is still confined to a loading period, variable amplitude loading situation complicated in engineering structure cannot be applicable to.For this problem, there is scholar to propose small time scales Analysis of Fatigue Crack Growth method, namely using the continuous print time as minimum measurement scale, to study within a loading period folding of fatigue crack and the transient behavior of growth in any time.
Under above-mentioned small time scales, the analysis of crack Propagation adopts in situ fatigue test, taken pictures by the consecutive variations behavior of scanning electron microscope to crack tip, thus measure crack Propagation increment and CTOD (Crack Tip Opening Displacement, crack tip opening displacement).But the maximum load that can apply due in situ fatigue test machine is limited, and scanning electron microscope enlargement factor causes more greatly the scope that can observe less, therefore be only applicable to thinner less sample, but this sample is in plane stress state, but the component in engineering mostly is plane strain state, make studied object and engineering practical structures not quite identical, therefore, need be obtained by additive method and be in the Crack Extension data of conventional examples under small time scales of plane strain state.
Summary of the invention
In order to solve exist in existing investigating fatigue crack expansion method measuring accuracy out of true, estimate by the residual life of trial product inaccurate, the present invention by microcosmic observation to crack morphology, and characterizes Crack Extension behavior by numerical information; For solving in small time scales fatigue life prediction, cause specimen size to have limitation due to the restriction of experimental provision, propose a kind of for be in plane strain state hardware, based on the investigating fatigue crack expansion method of replica and small time scales life prediction.The method adopts small time scales theory to analyze with multiple video collection, but the pattern of specimen surface is obtained by replica method, thus measure crack Propagation increment and CTOD, to carry out the prediction of fatigue lifetime, improve the safe handling of hardware.
Technical scheme of the present invention is:
Step one, theoretical according to small time scales on sample, choose five loading periods the Critical growth position from prefabricated gap position to crackle, in the compression and decompression process within each loading period, symmetry chooses ten test points respectively;
Step 2, adopts replication method for the first time to obtain the microscopic appearance of each test point, and under the sample after described replica is placed in scanning electron microscope; When Crack Extension increment clearly can carry out morphology observation under scanning electron microscope, then gather image; When Crack Extension increment cannot be seen clearly under scanning electron microscope, the second time replica of step 3 need be carried out;
Step 3, carries out morphology observation image collection under being placed in transmission electron microscope by needing the sample after double replica; According to morphology observation radiographic measurement crack Propagation increment and CTOD.
A kind of investigating fatigue crack expansion method based on replica and small time scales life prediction that the present invention proposes, is applicable to the metal component fatigue crack extend testing being in plane strain state.
Advantage and the good effect of the inventive method are:
(A), under small time scales the analysis of crack Propagation is using the continuous print time as minimum time yardstick, and it have received as a set of new theoretical system and pays close attention to very widely.But, due to the restriction to specimen size of its test unit, this analytical approach can only be applicable to the component of plane stress state, and then many places are in plane strain state for the component in engineering reality, and this limitation hinders small time scales theory and can not be applicable in engineering completely.In the methods of the invention, by replication method, the fatigue crack pattern being in plane strain state sample has been transferred on acetate film.So, no matter sample why geomery, observes under all the pattern of its fatigue crack can being placed in scanning electron microscope.The inventive method cannot carry out a difficult problem for Analysis On Fatigue Crack to plane strain state component under having filled up small time scales, the perfect further system of small time scales Analysis of Fatigue Crack Growth method.
(B) although also can be obtained the Life Prediction Model under plane strain state by certain theory deduction by the result under plane stress state, its accuracy and validity need textual criticism.The inventive method is the Forecasting Methodology of carrying out crack expansion test completely based on plane strain state sample, actual result is obtained by these test figures, and itself and theory deduction are carried out contrasting and verifying, make theoretical prediction model more accurate by improving.
(C), the inventive method has versatility to metal materials such as all aluminium alloys, titanium alloy, high temperature alloy, structural steel, and the scope of application widely.
(D) structure, in engineering practical structures is subject to complicated variable amplitude loading more, but definition sequence loading period is very difficult.The investigating fatigue crack expansion method of small time scales be in research arbitrary loading period not in the same time under, the folding behavior of fatigue crack and fatigue crack growth behavior, set up the crack Propagation model based on small time scales, thus realize the fatigue life prediction of the lower structure of complex load spectrum.
Accompanying drawing explanation
Fig. 1 is the specification figure that the present invention selects sample.
Fig. 2 A is constant amplitude loading of the present invention spectrum.
Fig. 2 B is complicated variable amplitude loading spectrum of the present invention.
Fig. 2 C is measurement point selected in each loading period of the present invention is schematic diagram.
Fig. 3 is replica pattern photo of the present invention.
Fig. 4 A is the schematic diagram of specimen surface replica position of the present invention.
Fig. 4 B is the photo of measurement Crack Extension increment of the present invention.
Fig. 5 is the relation curve of Crack Extension of the present invention increment-CTOD.
Fig. 6 is the process flow diagram that the present invention measures Crack Extension increment.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in further detail.
Shown in Figure 6, the present invention adopts replica and small time scales means to carry out investigating fatigue crack expansion to aviation 7050 series aluminium alloy material, the object of test be in order to solve exist in existing investigating fatigue crack expansion method measuring accuracy out of true, estimate and caused life prediction to be forbidden by the residual life of trial product is inaccurate, the present invention is by the microcosmic observation to crack morphology, and characterize Crack Extension behavior by numerical information, thus measure crack Propagation increment and CTOD, to carry out the prediction of fatigue lifetime, improve the safe handling of hardware.
Prepare sample
In the present invention, sample adopts standard SE (B) sample in GBT6398-2000 " Fatigue Crack Growth Rate of Metallic Materials test method ".
For convenience of description, as shown in Figure 1, W represents the wide of sample to sample, and length is wide 4.2 times.For avoiding individual sample to test the error produced, at least process the investigating fatigue crack expansion that three samples carry out put forward the methods of the present invention.
Prefabricated breach on standard SE (B) sample, notch depth is 0.1W.
The investigating fatigue crack expansion method based on replica and small time scales life prediction that the present invention proposes, includes the following step:
Step one: selecting test point
On standard SE (B) sample, choose five loading periods from prefabricated notch length in the limit increase of crackle critical dimension, in the loading within each loading period and/or uninstall process, symmetry chooses ten test points respectively; Five loading periods as shown in Figure 2 A, N
1, N
2, N
3, N
4, N
5; Arbitrarily choose and carry out the test of complicated variable amplitude loading spectrum suitable loading period, as shown in Figure 2 B.
In the present invention, within each loading period, if Identical loading type, then in loading procedure, choose 10 test point i, namely i=1,2,3 ..., 10.
In the present invention, within each loading period, to the crack tip closing phenomenon under research constant amplitude loading or study complicated variable amplitude loading spectrum, then need loading procedure and uninstall process respectively symmetry choose ten test point i, as shown in Figure 2 C.
Carry out in process in test of the present invention, if find always there is no crack opening at front several test point place when loading, the crackle when stress level reaches certain value is only had just to start to open, then record this stress strength factor K corresponding to point, then can not carry out replica to the test point before this point in the test of several loading period after which.The reason producing this phenomenon is caused by crack closure phenomenon.Because the value of Crack Extension increment and CTOD increases all gradually, therefore for making measurement result more even, selected loading period and test point should be tried one's best and be tending towards intensive gradually.
Step 2: replica obtains the microscopic appearance of each test point for the first time
Step 21: when breach is positioned at N (N=N
1, N
2, N
3, N
4, N
5) in individual loading period i-th (i=1,2,3 ..., 10) individual test point time, stop cyclic loading also to apply static load to sample;
Step 22: with the cotton ball cleaning breach surface being moistened with acetone, respectively at N
1, N
2, N
3, N
4, N
5five loading periods carry out replica measurement, cellulose acetate film drips 1-2 and drips acetone, then it is attached to gently sample crackle side surface respectively.After the dry 5min of film, clamp the end of film with tweezers, peel off lentamente from breach surface from top to bottom;
In the present invention, for helping the orientation distinguishing film, one of them angle of film can be cut off.
Step 23: for ensureing to obtain effective replica result, carry out three replicas respectively at crackle two side surfaces respectively, replication method repeats step 22, and each test point obtains 6 acetate films altogether;
Step 24: be pasted onto the glass sheet posting two-sided scotch tape by smooth for the acetate film after replica, and stick corresponding replica sequence number, replica sequence number should be corresponding with the stress level in this loading period with number loading period.
In the present invention, note when carrying out step 24 ensureing straight, corner angle are clear and distortionless, avoid sustaining damage.
Step 25: all samples are placed under scanning electron microscope and observe and (can observe until replica sample for the first time from last replica sample, also can observe in turn), if sample has image clearly under scanning electron microscope, then directly its feature image to be gathered, according to morphology observation radiographic measurement crack Propagation increment and CTOD; If it is fuzzyyer that image ratio observed by sample under scanning electron microscope, then carry out second time replica.
Observe the crackle microscopic appearance after first time replica sample, as shown in Figure 3.Because the enlargement factor of scanning electron microscope is limited, enlargement factor is usually between 5000 ~ 10000 times, and the minimum length that can observe is generally 0.1 ~ 0.2 μm.
In the present invention, when Crack Extension is greater than 0.2 μm, observe under directly the sample after above-mentioned replica being placed in scanning electron microscope; And when Crack Extension is less than 0.1 μm, scanning electron microscope is difficult to the increment observing Crack Extension, now need to carry out double replica, be placed on transmission electron microscope under observe.
In the present invention, according to the data of crack length-circulation cycle that each sample after first time replica obtains in torture test, estimating at the Crack Extension increment of time i-th test point place sample of N number of circulating cycle and CTOD, judging that this sample is the need of carrying out double replica.The sample of 0.2 μm can not be greater than for Crack Extension increment and CTOD simultaneously, need to carry out double replica, be placed on transmission electron microscope under observe.
Step 3: second time replica obtains the microscopic appearance of each test point
The sample can not observed under scanning electron microscope after screening through step 25 is carried out surface and do the process of spray carbon, as shown in (a) in Fig. 4 A, attention should make carbon film 1 even application on sample matrix 2, and controls carbon film thickness (b as in Fig. 4 A) within 20 μm.The crack length that the cycle that circulates residing for this sample is corresponding, roughly determines the position of crack tip, sample is cut into the fritter that about 3mm is square, is placed in acetone reagent to dissolve acetate film.When carbon film floats about 2 minutes, carbon film is transferred in another measuring cup filling fresh acetone reagent, then rinsing 5 minutes.Then directly put in acetone measuring cup or by carbon film with sample trawlnet and fishing for after the distillation water surface launches, obtain crack tip conversion sample 3 (c as in Fig. 4 A) after drying, can observe under transmission electron microscope, and take pictures.
Crack Propagation increment and the CTOD of each crack tip conversion sample is measured, as shown in Figure 4 B according to photo captured under transmission electron microscope.Make the relation curve of the Crack Extension increment Delta a-CTOD in each circulation cycle, and with the maximum stress intensity factor K corresponding to this circulating cycle minor peaks stress
maxvalue characterizes this curve, as shown in Figure 5.In figure, the Crack Extension increment in four circulation cycles is respectively: the maximum stress intensity factor value of first cycle is designated as K
max1, second cycle maximum stress intensity factor value be designated as K
max2, the 3rd cycle maximum stress intensity factor value be designated as K
max3k is designated as with the maximum stress intensity factor value of the 4th cycle
max4.
Investigating fatigue crack expansion method towards replica and small time scales life prediction provided by the invention, for the sample be under plane strain state, by replica technique to material within a loading period in any time the folding of fatigue crack and increment behavior observe, the fatigue life prediction for material provides basis.The method not only breaches the defect that classic fatigue durability analysis method is analyzed based on cyclic loading, and under more small time scales, more essential observation and the problem of research cannot be carried out to fatigue crack, more solve the limitation that current small time scales analytical approach can only analyze the sample be under plane stress state, make actual breakdown diagnosis result and engineering structure more close, improve accuracy and the confidence level of Analysis of Fatigue.
Claims (4)
1., based on an investigating fatigue crack expansion method for replica and small time scales life prediction, the sample carrying out investigating fatigue crack expansion is standard SE (B) sample; It is characterized in that the step that investigating fatigue crack expansion comprises is:
Step one, theoretical according to small time scales on sample, choose five loading periods the Critical growth position from prefabricated gap position to crackle, in the compression and decompression process within each loading period, symmetry chooses ten test points respectively;
Step 2, adopts replication method for the first time to obtain the microscopic appearance of each test point, and under the sample after described replica is placed in scanning electron microscope; When Crack Extension increment clearly can carry out morphology observation under scanning electron microscope, then gather image, and according to morphology observation radiographic measurement crack Propagation increment and CTOD; When Crack Extension increment cannot be seen clearly under scanning electron microscope, the second time replica of step 3 need be carried out;
Step 3, carries out morphology observation image collection under being placed in transmission electron microscope by needing the sample after double replica; And according to morphology observation radiographic measurement crack Propagation increment and CTOD.
2. the investigating fatigue crack expansion method based on replica and small time scales life prediction according to claim 1, it is characterized in that step 2 first time replica treatment step be:
Step 21: when breach is positioned at any one loading period of N i-th test point, stops cyclic loading and applies static load to sample;
Step 22: with the cotton ball cleaning breach surface being moistened with acetone, carry out replica measurement five loading periods respectively, cellulose acetate film drips 1-2 and drips acetone, then it is attached to gently sample crackle side surface respectively.After the dry 5min of film, clamp the end of film with tweezers, peel off lentamente from breach surface from top to bottom;
Step 23: for ensureing to obtain effective replica result, carry out three replicas respectively at crackle two side surfaces respectively, replication method repeats step 22, and each test point obtains 6 acetate films altogether;
Step 24: be pasted onto the glass sheet posting two-sided scotch tape by smooth for the acetate film after replica, and stick corresponding replica sequence number, replica sequence number should be corresponding with the stress level in this loading period with number loading period;
Step 25: observe under all samples are placed in scanning electron microscope, if sample has image clearly under scanning electron microscope, then directly to gather its feature image, and according to morphology observation radiographic measurement crack Propagation increment and CTOD; If it is fuzzyyer that image ratio observed by sample under scanning electron microscope, then carry out the second time replica of step 3.
3. the investigating fatigue crack expansion method based on replica and small time scales life prediction according to claim 2, is characterized in that: first time the crackle microscopic appearance minimum length of replica sample be 0.1 ~ 0.2 μm.
4. the investigating fatigue crack expansion method based on replica and small time scales life prediction according to claim 1, is characterized in that: the metal component fatigue crack extend testing being applicable to be in plane strain state.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106644784A (en) * | 2016-12-31 | 2017-05-10 | 北京航空航天大学 | Turbine disc damage tolerance assessment method considering multiple parts and multiple failure modes |
| CN104777046B (en) * | 2015-04-23 | 2017-05-10 | 北京航空航天大学 | Fatigue crack propagation mechanism testing method based on small time scale |
| CN106644783A (en) * | 2016-12-31 | 2017-05-10 | 北京航空航天大学 | Turbine disc-based low-cycle fatigue crack propagation life prediction method |
| CN108375514A (en) * | 2018-01-22 | 2018-08-07 | 北京工业大学 | A kind of experimental method obtaining metal sheet fatigue crackle situation with acetyl cellulose film replica |
| CN109670278A (en) * | 2019-02-26 | 2019-04-23 | 沈阳建筑大学 | A kind of Probabilistic Fatigue crack growth rate statistical analysis technique based on Gaussian Profile |
| CN110095360A (en) * | 2019-05-10 | 2019-08-06 | 中国电子产品可靠性与环境试验研究所（（工业和信息化部电子第五研究所）（中国赛宝实验室）） | The quick unstable extension mechanism test method of fatigue crack and system |
| CN111141776A (en) * | 2020-01-21 | 2020-05-12 | 鞍钢股份有限公司 | Method for judging fiber rate of 9Ni steel fracture |
| CN112285140A (en) * | 2020-10-20 | 2021-01-29 | 北京航空航天大学 | Quantitative characterization method for early-stage propagation rate of internal crack of single crystal ultrahigh cycle fatigue |
| CN114441336A (en) * | 2022-01-14 | 2022-05-06 | 中国石油大学(北京) | Method for testing CTOD-delta a resistance curve of metal |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0862112A (en) * | 1994-06-16 | 1996-03-08 | Mitsubishi Heavy Ind Ltd | Method for testing fatigue crack propagation of composite material |
| CN103105406A (en) * | 2011-11-09 | 2013-05-15 | 北京有色金属研究总院 | Method for observing crack propagation path of titanium alloy under plane strain state |
| US20130152697A1 (en) * | 2011-02-21 | 2013-06-20 | Fracturelab, Llc | Fatigue and/or Crack Growth Test Sample |
-
2014
- 2014-12-01 CN CN201410717199.XA patent/CN104406867B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0862112A (en) * | 1994-06-16 | 1996-03-08 | Mitsubishi Heavy Ind Ltd | Method for testing fatigue crack propagation of composite material |
| US20130152697A1 (en) * | 2011-02-21 | 2013-06-20 | Fracturelab, Llc | Fatigue and/or Crack Growth Test Sample |
| CN103105406A (en) * | 2011-11-09 | 2013-05-15 | 北京有色金属研究总院 | Method for observing crack propagation path of titanium alloy under plane strain state |
Non-Patent Citations (2)
| Title |
|---|
| 刘绍伦等: "《中华人民共和国国家标准GB/T6398-2000》", 1 June 2001 * |
| 陈长征等: ""风电机组叶片裂纹故障特征提取方法"", 《中国电机工程学报》 * |
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| CN104777046B (en) * | 2015-04-23 | 2017-05-10 | 北京航空航天大学 | Fatigue crack propagation mechanism testing method based on small time scale |
| CN106644784A (en) * | 2016-12-31 | 2017-05-10 | 北京航空航天大学 | Turbine disc damage tolerance assessment method considering multiple parts and multiple failure modes |
| CN106644783A (en) * | 2016-12-31 | 2017-05-10 | 北京航空航天大学 | Turbine disc-based low-cycle fatigue crack propagation life prediction method |
| CN106644784B (en) * | 2016-12-31 | 2018-11-16 | 北京航空航天大学 | A kind of turbine disk damage tolerance appraisal procedure considering multiple location and multi-invalidation mode |
| CN108375514A (en) * | 2018-01-22 | 2018-08-07 | 北京工业大学 | A kind of experimental method obtaining metal sheet fatigue crackle situation with acetyl cellulose film replica |
| CN108375514B (en) * | 2018-01-22 | 2020-04-24 | 北京工业大学 | Experimental method for obtaining fatigue small crack condition of metal plate by using cellulose acetate film replica |
| CN109670278A (en) * | 2019-02-26 | 2019-04-23 | 沈阳建筑大学 | A kind of Probabilistic Fatigue crack growth rate statistical analysis technique based on Gaussian Profile |
| CN110095360A (en) * | 2019-05-10 | 2019-08-06 | 中国电子产品可靠性与环境试验研究所（（工业和信息化部电子第五研究所）（中国赛宝实验室）） | The quick unstable extension mechanism test method of fatigue crack and system |
| CN111141776A (en) * | 2020-01-21 | 2020-05-12 | 鞍钢股份有限公司 | Method for judging fiber rate of 9Ni steel fracture |
| CN111141776B (en) * | 2020-01-21 | 2023-04-07 | 鞍钢股份有限公司 | Method for judging fiber rate of 9Ni steel fracture |
| CN112285140A (en) * | 2020-10-20 | 2021-01-29 | 北京航空航天大学 | Quantitative characterization method for early-stage propagation rate of internal crack of single crystal ultrahigh cycle fatigue |
| CN114441336A (en) * | 2022-01-14 | 2022-05-06 | 中国石油大学(北京) | Method for testing CTOD-delta a resistance curve of metal |
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