Correlations among growth law of small cracks, low-cycle fatigue law and applicability of miner's rule

Murakami, Yukitaka; Harada, Syoji; Endō, Takeshi; Tani-Ishi, H.; Fukushima, Yoshihiro

doi:10.1016/0013-7944(83)90066-8

Cited by 70 publications

(43 citation statements)

References 9 publications

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“…ψ is a reduction of area. 0 a is pre-micro-crack value that is no effect to fatigue damage under prior cycle loading [10]. …”

Section: The Life Prediction Calculations In Short Crackmentioning

confidence: 99%

The Life Predicting Calculations in Whole Process Realized by Calculable Materials Constants from short Crack to Long Crack Growth Process

Yu¹

2015

IJMSA

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Abstract:To use the theoretical approach, to adopt the simple stress-, or strain-parameter method, by means of the conventional material constants, to establish some new calculation models in whole crack growth process for elastic-plastic steels, which are the equations of the driving forces and the life predictions from micro to macro crack; To provide yet several crack growth-rate-linking-equations and life calculating expressions in whole process, for which are under different loading conditions in high cycle and low cycle fatigue. For key parameters A 1 , A 2 and B 2 have proposed some new concept, and to define their physical and geometrical meanings. For the transition crack size from crack forming stage to crack growth stage, provide concrete calculation processes and methods. Thereby to realized the lifetime predicting calculations in whole process based on traditional calculable material parameters. The purpose is to try to make the modern fatigue-fracture discipline depended on tests become gradually calculable subjects as the traditional material mechanics. So that will be having practical significances for saving testing manpower and funds, for promoting applying and development relevant disciplines.

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“…ψ is a reduction of area. 0 a is pre-micro-crack value that is no effect to fatigue damage under prior cycle loading [10]. …”

Section: The Life Prediction Calculations In Short Crackmentioning

confidence: 99%

The Life Predicting Calculations in Whole Process Realized by Calculable Materials Constants from short Crack to Long Crack Growth Process

Yu¹

2015

IJMSA

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“…6 shows FCGR calculated from l-N curve, which is the relationship between the crack length l and number of cycles N. The FCGR in hydrogen gas of the cyclic pre-strained specimen was 1.1~1.5 times higher than that of non pre-strained one. Generally, fatigue cycle history does not clearly affect the FCGR (16), (17) . In this case, it is possible that the FCGR was accelerated by the IG damage which was caused by the cyclic pre-strain.…”

Section: Effects Of Cyclic Pre-strain On Intergranular Fracture Ratiomentioning

confidence: 99%

Investigation of Mechanism for Intergranular Fatigue Crack Propagation of Low Carbon Steel JIS S10C in Hydrogen Gas Environment

Nishikawa

Oda

Nishikawa

2011

JMMP

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In order to investigate the mechanism for the intergranular fatigue crack propagation of a low carbon steel in a low pressure hydrogen gas environment, two kinds of examinations were carried out. One examined the effect of the cyclic pre-strain on the crack growth behavior. The other was the in-situ observation of intergranular fatigue crack propagation in a hydrogen gas environment. The main results are as follows. (1) SEM observation of the specimen surface morphology of a plain specimen fatigued in hydrogen gas showed that a gap at the grain boundary was induced by slip behavior, but not in nitrogen gas. (2) A specimen cyclic-prestrained in hydrogen gas showed slight influences on the increase in the crack propagation rate. (3) Mating intergranular facets on the fatigue fracture surfaces showed the matching of a striation-like pattern in the manner anticipated from the damage mechanism of (1). (4) The environment-change test from hydrogen to nitrogen during the fatigue test showed that intergranular facets appeared even in nitrogen. Results (3) and (4) suggests that the damaging process of (1) is valid in an actual fatigue crack. (5) In-situ observation of the crack propagation behavior in hydrogen gas showed that a crack propagated faster along the grain boundary. However, no visible discontinuous crack advances appeared as a large number of load repetitions was required. Phenomena considered to be a damage process (1) appeared ahead of a crack tip. Based on these results, a convincing mechanism for the intergranular fatigue crack propagation process is as follows. Grain boundaries just ahead of a crack tip are damaged due to the large number of hydrogen-enhanced slip repetitions, therefore, the fatigue crack becomes easier to propagate along the grain boundary in hydrogen.

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“…The relationship between plastic strain range ∆ε p and respective strain levels ∆ε i measured by the MRC can be derived by the following three Eqs. (6) -(8) (12) .…”

Section: 1 Fatigue Damage Based On the Modified Miner Rulementioning

confidence: 99%

“…On the contrary, the strain histogram under Cross-flow vibration distributed widely and has large number of strain frequency n for the much small strain range. Figure 16 shows the variation of the crack size with increase in the value of D. The experimental results showed that the nature of fatigue damage corresponded to crack growth (12) . That is, the fatigue life was dominated by the crack propagation process.…”

Section: 2 Strain Histogram For Cross-flow Vibration and In-line Vmentioning

confidence: 99%

Fatigue Failure by In-line Flow-induced Vibration and Fatigue Life Evaluation

Odahara

Murakami

Inoue

et al. 2005

JSME Int. J., Ser. A

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The phenomenon of fatigue failure due to In-line flow-induced vibration has been investigated. In the experimental program an induced-vibration experimental set-up involving water flow was developed. This apparatus was used to produce fatigue failure resulting from In-line flow-induced vibration. The fatigue specimens were made of a medium carbon steel. A small hole was drilled into the specimen surface to localize the fatigue cracking process. A strain histogram recorder (Mini Rainflow Corder, MRC) was used to acquire the service strain histogram and also to detect any variations in natural frequency. The cumulative fatigue damage, D, as defined by the Modified Miner Rule, was determined by using the strain histogram of the early portion of the test record. The value of D was almost unity in the case of In-line vibration. In contrast, the value of D obtained in a previous investigation for the case of the Cross-flow vibration ranged approximately from 0.2 to 0.8.

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Correlations among growth law of small cracks, low-cycle fatigue law and applicability of miner's rule

Cited by 70 publications

References 9 publications

The Life Predicting Calculations in Whole Process Realized by Calculable Materials Constants from short Crack to Long Crack Growth Process

The Life Predicting Calculations in Whole Process Realized by Calculable Materials Constants from short Crack to Long Crack Growth Process

Investigation of Mechanism for Intergranular Fatigue Crack Propagation of Low Carbon Steel JIS S10C in Hydrogen Gas Environment

Fatigue Failure by In-line Flow-induced Vibration and Fatigue Life Evaluation

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