Issue 30
A. Fernà ndez-Canteli et alii, Frattura ed Integrità Strutturale, 30 (2014) 327-339; DOI: 10.3221/IGF-ESIS.30.40
between the experimental V values and those of the Miner number M is established, allowing the cdf predicted for the experimental Miner results to be established by simple mapping of the Miner numbers obtained for the experimental test failures into probabilities of failure, see Fig. 7. Accordingly, an approach for probabilistic lifetime prediction is established by means of the normalized variable V that improves the reliability provided by the conventional Miner rule.
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Probability of failure
Probability of failure
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Probability of failure
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Miner number
Miner number
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Probability of failure
V [normalized variable]
Figure 7: From the experimental Weibull cumulative distribution function for the normalized variable V (upper-right) and the established relation between V and M (down-right), the experimental cdf of the Miner number (down-left) is found for the fatigue of Holmen [5]. Now, the cumulative distribution function for the Miner number sample obtained from the results of the experimental program with varying stress range tests of Holmen is determined by applying any plotting point position rule. The Miner number values are ranged in increasing order and the corresponding probabilities of failure calculated. The resulting cdf is compared with that predicted from the normalized variable V distribution, as shown in Fig. 8.
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Probabilty of failure
Probabilty of failure
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Fitting acording to Weibull: p=0.5 & Scale factor=2.364 Experimental data p=0.5
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Fitting acording to Weibull: p=0.5 & Scale factor=1 Experimental data p=0.5
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Miner number
Miner number
(a)
(b)
336
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