Qualification of SN curve by experiments: estimation of survival probability for a low number of experiments
Thibaux, P.; Tonesi, C. (2015). Qualification of SN curve by experiments: estimation of survival probability for a low number of experiments, in: Proceedings of the ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2015): Volume 3: Structures, Safety and Reliability. pp. 16. https://hdl.handle.net/10.1115/OMAE201541754
In: (2015). Proceedings of the ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2015): Volume 3: Structures, Safety and Reliability. ASME: New York. ISBN 9780791856499.

Beschikbaar in  Auteurs 

Documenttype: Congresbijdrage

Abstract 
Due to the cost of fatigue testing, qualification of new weld details or improved welding techniques is often performed by comparing the experimental results with a mean SN curve. The experimental dataset is considered to qualify for a given SN curve if the mean of the log of the experimental results is larger than the mean of the chosen SN curve plus an interval depending on the chosen confidence level. The confidence level is generally chosen arbitrary high, typically 75% or 90%. The survival estimation does not take into account the risk incurred by the fact that the actual mean has a probability of 25% or 10% of being lower than the theoretical SN curve. In the present paper, we propose a different methodology based on the design SN curve. The probability of failure for a given load level is computed by combining the probability of failure considering the mean value of the SN curve, and the probability of this mean value. Thanks to the present method it is possible to estimate the probability of failure without making an assumption on the confidence level, which reduces the arbitrary during the estimation of the test results, particularly when the number of experimental results is limited. 
