Issue 41

M.V.C Sá et alii, Frattura ed Integrità Strutturale, 41 (2017) 90-97; DOI: 10.3221/IGF-ESIS.41.13 94 Figure 3: Scheme of the life estimation methodology used in the multiaxial fatigue tests. (a) (b) Figure 4: σ-N and τ-N curves of plain and notched specimens performed under fully reversed (a) push-pull and (b) torsion conditions. The trend line and the scatter bands sketched in these diagrams are characterized by a significance level equal to 95% (it was assumed, by hypothesis, that a log-normal distribution represents the number of cycles to failure). The synthesis of the generated results, carried out according to the above statistical procedure, is summarized in Tab. 2. The endurance limits reported in such a Table were raised based on the parallel projection method (considering a number of cycles for Gross Amplitude Stress, a [ MPa ] 10 3 10 4 10 5 10 6 10 7 10 8 Number of Cycles to Failure , N f 10 100 20 30 40 50 60 70 80 90 200 300 400 500 Sample Observations - Unnotch Sample Observations - Notch Trend Line - Unnotch Trend Line - Notch 95% Prediction Intervals