Ab&W-The effects of stress ratio on fatigue crack growth thresholds and low and intermediate fatigue crack growth r8tes are ex8mined on steels with ferri+pearlii and tempered martensite micros~c~s, tested in air. The analysis of available experimental data shows that simple empirical relationships c
The effect of load ratio on the threshold stresses for fatigue crack growth in medium carbon steels
โ Scribed by R.J. Cooke; C.J. Beevers
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 821 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0013-7944
No coin nor oath required. For personal study only.
โฆ Synopsis
A study of the effect of load ratio, R, on the low crack growth rates and the threshold stress conditions exhibited by five medium carbon steels has been conducted. It was found that decreased values of R retarded crack growth to an increasing degree as a defined threshold for crack growth was approached, such that this threshold showed a marked dependence on K max rather than AK. Comparisons of the five materials showed that the threshold increased as yield strength increased for a given R, but this effect could be normalised in terms of a constant value of the maximum plastic zone size at the crack tip.
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Centrally cracked specimens of JIS SM58Q and I-IT80 steels were fatigued. The fatigue crack growth rates, da/dn, and the stress intensity threshold levels, AK,, were measured over the range of stress ratio, R, from -1 to 0.8 by the use of an automatic method of continuously decreasing stress intensi
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I SHOULD like to compliment Dr Beevers and his co-workers on their paper. It is pleasing to see at last some mechanistic basis to the problem of fatigue crack propagation in steels at stresses approaching the threshold stress intensity for crack growth. Such data are still extremely scarce in the li