Probabilistic approach to predict the very high-cycle fatigue behaviour of spheroidal graphite cast iron structures

Abstract

A new probabilistic approach is developed to study structures made of spheroidal graphite cast iron and subjected to very high-cycle fatigue. Until now, the probabilistic approach was based on S-N curves obtained from experiments carried out only until 107 cycles. To validate this approach, failure predictions relating to the safety of components are computed and compared to experimental results. In addition to this development, an extension is proposed in order to improve the very long life assessment of complex structures. An extrapolation of the previous fatigue results to 109-1011 cycles illustrates the error made on cumulative failure probabilities. Finally, the respective influence of the casting flaw distribution, volume and stress field heterogeneity within specimens and industrial components is studied.