An investigation of the location of fatigue initiation - Deterministic and probabilistic aspects
2014 (English)In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 66, 65-77 p.Article in journal (Refereed) Published
Fatigue limit tests where there are two competing fatigue failure locations, two notches of different size, are performed in this paper. The normal distribution is used for describing the experimental outcome, where the largest occurring stress value or the gradient adjusted stress is used as a stress measure. Another model for describing the experimental outcome is the Weakest Link (WL)-integral where the integration is performed over the specimen surface area or the specimen volume. In addition, the positions of the fatigue failure initiation sites are measured and investigated. The predictive capabilities of the different models are evaluated with respect to determination of the longitudinal failure location. A notable result is that the longitudinal location of fatigue failure differs considerably from one experiment to the other, even when they are numerically equal. Nominally the stress at the fatigue failure site is much lower than the maximal stress. The load cases where there should be an equal amount of failures in both notches according to the models used do not agree with the experimental findings. Neither the point stress model nor the gradient adjusted point stress, nor the WL-integral can explain the experimental outcome from the competing notch tests.
Place, publisher, year, edition, pages
2014. Vol. 66, 65-77 p.
Experiments, Probabilistic model, Stress gradients, Weakest link integral, Competing failure locations
IdentifiersURN: urn:nbn:se:kth:diva-148598DOI: 10.1016/j.ijfatigue.2014.03.010ISI: 000338622000008ScopusID: 2-s2.0-84901985312OAI: oai:DiVA.org:kth-148598DiVA: diva2:737217
QC 201408122014-08-122014-08-112014-08-12Bibliographically approved