CN102937520A - Fatigue life prediction method of mechanical component under variable amplitude loading - Google Patents
Fatigue life prediction method of mechanical component under variable amplitude loading Download PDFInfo
- Publication number
- CN102937520A CN102937520A CN2012104484813A CN201210448481A CN102937520A CN 102937520 A CN102937520 A CN 102937520A CN 2012104484813 A CN2012104484813 A CN 2012104484813A CN 201210448481 A CN201210448481 A CN 201210448481A CN 102937520 A CN102937520 A CN 102937520A
- Authority
- CN
- China
- Prior art keywords
- damage
- life
- span
- variable amplitude
- under
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention relates to a fatigue life prediction method of a mechanical component under variable amplitude loading and aims to disclose that the secondary load and overload strengthening can not be prevented in terms of material and structure failure mechanism under the variable amplitude loading and the material and structure fatigue life prediction under complex serving condition and the like. The method includes that on the basis of an S-N curve of the mechanical component, a damage line is introduced, service life in each process is predicted, finally the obtained fatigue life of the mechanical component under the variable amplitude loading is an accumulated sum of a strengthening process service life, a damage-free process service life and a damage process service life of the load, during the service life prediction process, the secondary load strengthening effect and overload damage-free effect under the variable amplitude loading are fully considered, and the load acceleration damage process is further considered. The prediction process is close to the test and actual conditions, and the method is remarkably superior to prior methods. The method is applicable to the service life prediction of steel mechanical component under high-cycle fatigue damage.
Description
Technical field
The present invention relates to a kind of forecasting fatigue method, particularly under a kind of variable amplitude loading based on the mechanical components Prediction method for fatigue life of lesion wire and stress life line.
Background technology
The load that most of component of machine bears in the engineering is luffing, and general variable amplitude loading had both comprised the overload that fatigue limit is above, comprises again inferior the carrying that fatigue limit is following.The research of fatigue life prediction is the important topic in the fatigue study always under the variable amplitude loading.
The Prediction method for fatigue life of Miner rule commonly used, correction Miner rule, bilinearity theory and Corton-Dolan theory etc. in engineering, too much consideration the damaging action of load, ignore the reinforcement of load, therefore, under prediction weak reinforcement loading spectrum or original load spectrum, existing methodical predicting the outcome compared the larger difference of existence with test findings, and it is too safe to predict the outcome, and is unfavorable for the lightweight of zero member.
A large amount of torture tests show, some load cycle that mechanical material and structure are born in the process under arms not only produces damage, also produce invigoration effect, particularly when load is near the fatigue limit or is slightly less than fatigue limit, reinforcing degree and the degree of injury of load are more approaching, even surpass degree of injury.The reinforcement of load can be divided into time year reinforcement (also claiming low load reinforcing, underloads, coaxing effects or understressing) and overload reinforcement (also claiming Overloading effect, overloads or overstressing) in the fatigue process.All can not avoid time carrying for the fatigue life prediction that discloses material and structure under material and structural damage mechanism under the variable amplitude loading, the complicated service condition of prediction etc. and strengthen and the overload reinforcement.
Summary of the invention
The present invention be directed to predicting the outcome of present mechanical components forecasting fatigue method and compare the problem of the larger difference of existence with test findings, mechanical components Prediction method for fatigue life under a kind of variable amplitude loading has been proposed, take the S-N curve of mechanical components as the basis, introduce lesion wire.In the life prediction process, taken into full account time year strengthening effect and the overload not damaged effect under the variable amplitude loading, consider again load acceleration damage process.Forecasting process will closer to test and actual conditions, obviously be better than existing method.
Technical scheme of the present invention is: the mechanical components Prediction method for fatigue life under a kind of variable amplitude loading specifically comprises the steps:
1) determines the stress life line of mechanical components, i.e. the S-N curve;
2) determine the lesion wire of mechanical components;
3) take green strength as reference, by lesion wire and S-N curve the effect of the above load of fatigue limit (being called for short overload) is divided into two large zones, be not damaged zone and damage field, the not damaged zone is the following zone of lesion wire, and damage field is the zone between lesion wire and the S-N curve;
4) according to lesion wire and S-N curve, the not damaged process life-span of computation overload and damage process life-span, determine the Damage coefficient of transshipping;
5) reinforcement and the damage of the following load of fatigue limit (being called for short inferior carrying) are calculated under the variable amplitude loading, determine the reinforcement potential of zero member under the variable amplitude loading, inferior year strengthening process life-span and damage process life-span;
6) fatigue life prediction of zero member under the variable amplitude loading, be the accumulation sum in strengthening process life-span, not damaged process life-span and the damage process life-span of load the fatigue lifetime of zero member under the variable amplitude loading,
1. strengthening process life-span: according to the reinforcement number of times that carries of homogeneous not of the method linear accumulation in the step 5);
2. not damaged process life-span: as fruit structure through time carry strengthen after, do not calculate the not damaged process life-span; Otherwise need the computation overload not damaged process life-span, the computing experience that carries the not damaged process life-span can be estimated according to linear accumulation.Overload not damaged cumulative frequency sum is 1, and when namely following formula was set up, overload not damaged process was finished, the accumulation of different loads and be exactly the entire life in not damaged zone,
3. damage process life-span: damage accumulation number of times sum is 1, and when namely following formula was set up, the damage process of load was finished, i.e. zero component failure,
, N wherein
SiBe the damage process life-span of i level load, m is load when arriving this grade load, zero component failure.
Beneficial effect of the present invention is: the mechanical components Prediction method for fatigue life under the variable amplitude loading of the present invention, take the S-N curve of mechanical components as the basis, introduce lesion wire.In the life prediction process, taken into full account time year strengthening effect and the overload not damaged effect under the variable amplitude loading, consider again load acceleration damage process.Forecasting process will closer to test and actual conditions, obviously be better than existing method.This method is applicable to the life prediction under the iron and steel class mechanical components high cycle fatigue destruction.
Description of drawings
Fig. 1 is S-N curve and damage line chart in the mechanical components Prediction method for fatigue life under the variable amplitude loading of the present invention;
Fig. 2 is overload damage figure in the mechanical components Prediction method for fatigue life under the variable amplitude loading of the present invention;
Fig. 3 time carries damage figure in the mechanical components Prediction method for fatigue life under the variable amplitude loading of the present invention.
Embodiment
Mechanical components Prediction method for fatigue life body implementation step based on lesion wire and stress life line under a kind of variable amplitude loading is as follows:
(1) determines the stress life line of mechanical components, i.e. the S-N curve;
The S-N curve of mechanical components can obtain by traditional torture test, also can estimate by S-N Curve.
Under log-log coordinate, the S-N curve of mechanical components is straight line.Typical S-N curve form is as follows:
In the formula: α, C---material constant.
(2) determine the lesion wire of mechanical components;
The lesion wire of determining material or part has two kinds of methods: the one, and test method(s), the 2nd, estimation algorithm.
1. test method(s): the line of the maximum overload cycle index that fatigue limit does not reduce is lesion wire, and namely overload does not produce the maximum times line of damage.
2. estimation algorithm: according to lesion wire and S-N curve definitions, they intersect in the S-N curve break, and as shown in Figure 1, a large amount of test figures shows that lesion wire also is straight line under double-log, and slope is about 2/3 of S-N curve.
The typical form of lesion wire is under the log-log coordinate:
In the formula: C '---material constant, can be tried to achieve by following formula.
In the formula: S
-1---the fatigue limit of material or part, N
0---the corresponding cycle index of S-N curve break, structural steel generally gets 10
7
(3) take green strength as reference, by lesion wire and S-N curve the effect of the above load of fatigue limit (being called for short overload) is divided into two large zone, i.e. not damaged zone and damage fields;
By lesion wire and S-N curve, the effect of overloading load can be divided into two zones, namely the following zone of lesion wire is the not damaged zone, the zone between lesion wire and the S-N curve is damage field.
(4) according to lesion wire and S-N curve, the not damaged process life-span of computation overload and damage process life-span, determine the Damage coefficient of transshipping;
1. according to lesion wire, can calculate the not damaged zone life-span of overload
In the formula: N
d---the not damaged zone life-span of overload.
2. according to lesion wire and S-N curvilinear equation, can calculate the damage field life-span of overload
In the formula: N
s---the damage field life-span of overload
In the situation of linear damage, the Damage coefficient of different loads is 1/N
sThe black solid line of damage process in as shown in Figure 2.
(5) reinforcement and the damage of the following load of fatigue limit (being called for short inferior carrying) are calculated under the variable amplitude loading, determine the reinforcement potential of zero member under the variable amplitude loading, inferior year strengthening process life-span and damage process life-span;
If contain the little load below the fatigue limit in the variable amplitude loading, for more accurately bimetry, at first consideration time year reinforcement and next year damage of variable amplitude loading.
Carry variable amplitude loading next time strengthen, strengthen potential according to existing low load reinforcing method process (list of references. the experimental study of cylindrical gear low load reinforcing. China Mechanical Engineering, 2005,16 (23): 2109-2111.), suppose reach strengthen potential after, the zero new parallel original S-N curve of S-N curve of member.The strengthening process life-span is the homogeneous linear accumulation sum of carrying strengthening process not.
Carrying variable amplitude loading next time damage process can determine according to test findings, also can simply process Damage coefficient as constant, such as accelerating 10 times etc.
Mechanical components will enter the damage passage after strengthening end under new S-N curve, and at this moment, all load will be in damage process, suppose that original overload damage coefficient is constant in new damage passage, and extension line 0 as shown in Figure 3 arrives-the K section.
(6) fatigue life prediction of zero member under the variable amplitude loading, be the accumulation sum in strengthening process life-span, not damaged process life-span and the damage process life-span of load the fatigue lifetime of zero member under the variable amplitude loading.
1. strengthening process life-span: according to the reinforcement number of times that carries of homogeneous not of the method linear accumulation in the step 5.
2. not damaged process life-span: as fruit structure through time carry strengthen after, do not calculate the not damaged process life-span; Otherwise need the computation overload not damaged process life-span, the computing experience that carries the not damaged process life-span can be estimated according to linear accumulation.Overload not damaged cumulative frequency sum is 1, and when namely formula (5) was set up, overload not damaged process was finished, the accumulation of different loads and be exactly the entire life in not damaged zone.
In the formula: n
i---every grade of load number of times; The progression of m---variable amplitude loading; N
Di---the i level load not damaged process life-span.
3. damage process life-span: damage accumulation number of times sum is 1, and when namely formula (6) was set up, the damage process of load was finished, i.e. zero component failure.
In the formula: N
Si---the damage process life-span of i level load.
Wherein, when m---load arrives this grade load, zero component failure.
4. be exactly the accumulation sum in strengthening process life-span, not damaged process life-span and damage process life-span the fatigue lifetime of mechanical components.
Claims (8)
1. the mechanical components Prediction method for fatigue life under the variable amplitude loading is characterized in that, specifically comprises the steps:
1) determines the stress life line of mechanical components, i.e. the S-N curve;
2) determine the lesion wire of mechanical components;
3) take green strength as reference, by lesion wire and S-N curve the effect of the above load of fatigue limit (being called for short overload) is divided into two large zones, be not damaged zone and damage field, the not damaged zone is the following zone of lesion wire, and damage field is the zone between lesion wire and the S-N curve;
4) according to lesion wire and S-N curve, the not damaged process life-span of computation overload and damage process life-span, determine the Damage coefficient of transshipping;
5) reinforcement and the damage of the following load of fatigue limit (being called for short inferior carrying) are calculated under the variable amplitude loading, determine the reinforcement potential of zero member under the variable amplitude loading, inferior year strengthening process life-span and damage process life-span;
6) fatigue life prediction of zero member under the variable amplitude loading, be the accumulation sum in strengthening process life-span, not damaged process life-span and the damage process life-span of load the fatigue lifetime of zero member under the variable amplitude loading,
1. strengthening process life-span: according to the reinforcement number of times that carries of homogeneous not of the method linear accumulation in the step 5);
2. not damaged process life-span: as fruit structure through time carry strengthen after, do not calculate the not damaged process life-span; Otherwise need the computation overload not damaged process life-span, the computing experience that carries the not damaged process life-span can be estimated according to linear accumulation;
Overload not damaged cumulative frequency sum is 1, and when namely following formula was set up, overload not damaged process was finished, the accumulation of different loads and be exactly the entire life in not damaged zone,
, in the formula: n
iBe every grade of load number of times, m is the progression of variable amplitude loading, N
DiIt is the i level load not damaged process life-span;
3. damage process life-span: damage accumulation number of times sum is 1, and when namely following formula was set up, the damage process of load was finished, i.e. zero component failure,
2. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 1 is characterized in that the S-N curve in the described step 1) can obtain by traditional torture test, also can estimate by S-N Curve.
3. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 1 is characterized in that the S-N curve is straight line in the described step 1) under log-log coordinate, and equation is as follows:
4. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 1, it is characterized in that, described step 2) lesion wire obtains with experimental method in: the line of the maximum overload cycle index that fatigue limit does not reduce is lesion wire, and namely overload does not produce the maximum times line of damage.
5. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 1 is characterized in that described step 2) in lesion wire obtain with estimation algorithm: lesion wire also is straight line under double-log, equation is as follows:
6. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 5 is characterized in that the not damaged process life-span of transshipping in the described step 4) calculates according to lesion wire:
, N
dBe the not damaged zone life-span of overload,, S wherein
-1Be the fatigue limit of material or part, N
0Be the corresponding cycle index of S-N curve break, α is material constant.
7. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 1 is characterized in that the damage field life-span of transshipping in the described step 4) calculates according to lesion wire and S-N curvilinear equation:
, N wherein
sBe the damage field life-span of overload, N
dBe the not damaged zone life-span of overload,
,
, S wherein
-1Be the fatigue limit of material or part, N
0Be the corresponding cycle index of S-N curve break, α is material constant, and in the situation of linear damage, the Damage coefficient of different loads is 1/N
s
8. the mechanical components Prediction method for fatigue life under the described variable amplitude loading according to claim 7 is characterized in that, variable amplitude loading carries damage process can determine according to test findings next time in the described step 5), also can process Damage coefficient as constant; Mechanical components will enter the damage passage after strengthening end under new S-N curve, and at this moment, all load will be in damage process, suppose that original overload damage coefficient is constant in new damage passage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012104484813A CN102937520A (en) | 2012-11-12 | 2012-11-12 | Fatigue life prediction method of mechanical component under variable amplitude loading |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012104484813A CN102937520A (en) | 2012-11-12 | 2012-11-12 | Fatigue life prediction method of mechanical component under variable amplitude loading |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102937520A true CN102937520A (en) | 2013-02-20 |
Family
ID=47696431
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012104484813A Pending CN102937520A (en) | 2012-11-12 | 2012-11-12 | Fatigue life prediction method of mechanical component under variable amplitude loading |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102937520A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103308297A (en) * | 2013-05-31 | 2013-09-18 | 深圳麦克维尔空调有限公司 | Judgment method for tubing of air conditioner |
| CN103778276A (en) * | 2013-12-27 | 2014-05-07 | 河海大学 | Reliability degree predication method for composite material based on fatigue life distribution |
| CN104089760A (en) * | 2014-06-18 | 2014-10-08 | 潍柴动力股份有限公司 | Fatigue test method of internal combustion engine part |
| CN104515685A (en) * | 2013-09-30 | 2015-04-15 | 上海汇众汽车制造有限公司 | Method of evaluating durability of torsion beam rear axle on basis of road load |
| CN104460339B (en) * | 2014-10-27 | 2017-02-15 | 上海理工大学 | Active load spectrum control method used for designing automobile transmission structures in lightweight mode |
| CN107271204A (en) * | 2017-03-30 | 2017-10-20 | 中车齐齐哈尔车辆有限公司 | Non- constant amplitude thresholding data compression method and device |
| CN108169013A (en) * | 2017-12-01 | 2018-06-15 | 中国航空工业集团公司沈阳飞机设计研究所 | A kind of fatigue life calibration method suitable for Multi-fasteners joint test specimen |
| CN111855446A (en) * | 2020-07-14 | 2020-10-30 | 天津钢管制造有限公司 | Prediction method of fatigue limit of titanium alloy |
| CN111881564A (en) * | 2020-07-17 | 2020-11-03 | 北京理工大学 | Method for predicting amplitude-variable fatigue life of mechanical structure |
| CN112197947A (en) * | 2020-09-25 | 2021-01-08 | 中国直升机设计研究所 | Method for calculating extension of service life curve of helicopter in low service life area |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5717607A (en) * | 1995-10-16 | 1998-02-10 | Ford Motor Company | Computer program, system and method to reduce sample size in accelerated reliability verification tests |
| CN102156066A (en) * | 2011-03-28 | 2011-08-17 | 上海理工大学 | Method for predicating fatigue life of mobile S-N (Stress-Life) curve on basis of strengthening and damage |
| US20120271566A1 (en) * | 2011-04-21 | 2012-10-25 | Vinayak Deshmukh | Method for the prediction of fatigue life for structures |
-
2012
- 2012-11-12 CN CN2012104484813A patent/CN102937520A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5717607A (en) * | 1995-10-16 | 1998-02-10 | Ford Motor Company | Computer program, system and method to reduce sample size in accelerated reliability verification tests |
| CN102156066A (en) * | 2011-03-28 | 2011-08-17 | 上海理工大学 | Method for predicating fatigue life of mobile S-N (Stress-Life) curve on basis of strengthening and damage |
| US20120271566A1 (en) * | 2011-04-21 | 2012-10-25 | Vinayak Deshmukh | Method for the prediction of fatigue life for structures |
Non-Patent Citations (5)
| Title |
|---|
| 卢曦 等: "考虑小载荷强化的汽车构件疲劳累积损伤试验研究", 《中国机械工程》, vol. 18, no. 8, 30 April 2007 (2007-04-30), pages 994 - 997 * |
| 才庆魁: "《金属疲劳断裂理论》", 30 September 1989, article "第六章 影响疲劳的因素", pages: 159 * |
| 李玉鹏 等: "疲劳损伤线的初步研究", 《上海理工大学学报》, vol. 32, no. 5, 31 December 2010 (2010-12-31), pages 454 - 456 * |
| 赵少汴 等: "《疲劳设计》", 31 October 1992, article "材料疲劳强度", pages: 13-15 - 84-90 * |
| 郁望达 等: "试验对象对低载强化特性影响的研究", 《机械科学与技术》, vol. 31, no. 5, 31 May 2012 (2012-05-31), pages 731 - 734 * |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103308297A (en) * | 2013-05-31 | 2013-09-18 | 深圳麦克维尔空调有限公司 | Judgment method for tubing of air conditioner |
| CN103308297B (en) * | 2013-05-31 | 2015-09-09 | 深圳麦克维尔空调有限公司 | The decision method of the pipe arrangement of air-conditioning |
| CN104515685A (en) * | 2013-09-30 | 2015-04-15 | 上海汇众汽车制造有限公司 | Method of evaluating durability of torsion beam rear axle on basis of road load |
| CN104515685B (en) * | 2013-09-30 | 2017-10-13 | 上海汇众汽车制造有限公司 | Torsion beam rear axle durability evaluation method based on road load |
| CN103778276A (en) * | 2013-12-27 | 2014-05-07 | 河海大学 | Reliability degree predication method for composite material based on fatigue life distribution |
| CN103778276B (en) * | 2013-12-27 | 2016-08-31 | 河海大学 | Composite Predicting Reliability method based on FATIGUE LIFE DISTRIBUTION |
| CN104089760A (en) * | 2014-06-18 | 2014-10-08 | 潍柴动力股份有限公司 | Fatigue test method of internal combustion engine part |
| CN104460339B (en) * | 2014-10-27 | 2017-02-15 | 上海理工大学 | Active load spectrum control method used for designing automobile transmission structures in lightweight mode |
| CN107271204A (en) * | 2017-03-30 | 2017-10-20 | 中车齐齐哈尔车辆有限公司 | Non- constant amplitude thresholding data compression method and device |
| CN107271204B (en) * | 2017-03-30 | 2019-07-23 | 中车齐齐哈尔车辆有限公司 | Non- constant amplitude thresholding data compression method and apparatus |
| CN108169013A (en) * | 2017-12-01 | 2018-06-15 | 中国航空工业集团公司沈阳飞机设计研究所 | A kind of fatigue life calibration method suitable for Multi-fasteners joint test specimen |
| CN108169013B (en) * | 2017-12-01 | 2020-04-14 | 中国航空工业集团公司沈阳飞机设计研究所 | Fatigue life calibration method suitable for multi-nail connection test piece |
| CN111855446A (en) * | 2020-07-14 | 2020-10-30 | 天津钢管制造有限公司 | Prediction method of fatigue limit of titanium alloy |
| CN111855446B (en) * | 2020-07-14 | 2023-07-04 | 天津钢管制造有限公司 | Method for predicting fatigue limit of titanium alloy |
| CN111881564A (en) * | 2020-07-17 | 2020-11-03 | 北京理工大学 | Method for predicting amplitude-variable fatigue life of mechanical structure |
| CN111881564B (en) * | 2020-07-17 | 2022-09-09 | 北京理工大学 | Method for predicting amplitude-variable fatigue life of mechanical structure |
| CN112197947A (en) * | 2020-09-25 | 2021-01-08 | 中国直升机设计研究所 | Method for calculating extension of service life curve of helicopter in low service life area |
| CN112197947B (en) * | 2020-09-25 | 2022-06-21 | 中国直升机设计研究所 | Method for calculating extension of service life curve of helicopter in low service life area |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102937520A (en) | Fatigue life prediction method of mechanical component under variable amplitude loading | |
| CN102156066A (en) | Method for predicating fatigue life of mobile S-N (Stress-Life) curve on basis of strengthening and damage | |
| Ince | A mean stress correction model for tensile and compressive mean stress fatigue loadings | |
| CN109635385B (en) | Part service life prediction method comprehensively considering fatigue strength influence factors | |
| CN109165407A (en) | A kind of predictor method for the mechanical component fatigue crack service life | |
| CN102967512B (en) | Low cycle fatigue life prediction method based on asymmetrical cyclic stress control load | |
| CN109855959B (en) | Prediction method for fatigue strength of metal material | |
| CN101122560A (en) | Mechanical structure crack expansion rate and crack expansion life span predication method | |
| CN109726411B (en) | Method for calculating fatigue strength of cabin structure of wind turbine | |
| CN109255202A (en) | A kind of predictor method for mechanical component fatigue crack initiation life | |
| CN105718606B (en) | A kind of vehicle heavy-duty gear method for predicting reliability considering Failure Mode Correlation | |
| CN110417013B (en) | Power system stabilizer parameter setting method and readable storage medium | |
| CN112711835A (en) | Metal material fatigue life prediction method based on corrected plastic strain energy | |
| Shi et al. | Prediction of fatigue crack growth based on low cycle fatigue properties | |
| CN111950094A (en) | Multi-load fatigue life constraint topology optimization method | |
| CN112784347B (en) | Cable-stayed bridge cable force reliability evaluation method based on bridge tower deformation and considering cable breakage | |
| CN111079225B (en) | Helicopter structure fatigue life curve calculation method and device | |
| JP5621414B2 (en) | Equipment management method | |
| CN111400922B (en) | Method for calculating stress-strain behavior of unidirectional ceramic matrix composite material by adding and removing random strain | |
| CN110390173B (en) | Time-varying reliability evaluation method for kilometer deep well elevator considering residual strength degradation | |
| CN110147643B (en) | Method and device for determining residual life of coupler body | |
| CN104612062A (en) | Structure prestress comprehensive reinforcement method utilizing action of environment temperature difference | |
| KR101257765B1 (en) | Method for designing optimized tunnel segment with high strength | |
| CN204325948U (en) | A kind of external prestressing unloading consolidation device utilizing assembly pulley principle | |
| Polishchuk et al. | Life time assessment of clamp-forming machine boom durability |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20130220 |