Issue 41

Carpinteri A. et alii, Frattura ed Integrità Strutturale, 41 (2017) 40-44; DOI: 10.3221/IGF-ESIS.41.06 43 Figures 3-5 present overall damage comparisons, by plotting the ratio of expected fatigue damage per unit time, [ ] E D , to the reference damage per unit time, [ ] ref E D . Such a reference value [ ] ref E D depends on the spectra type: - for type (i), it represents the damage produced by two sinusoidal signals characterized by pulsations equal to ,11 c  and ,66 c  , respectively, and variance equal to 0,11  and 0,66  , respectively; - for types (ii) and (iii), it represents the damage produced by three sinusoidal signals characterized by pulsations equal to ,11 c  , ,66 c  , and ,16 c  , respectively, and variance equal to 0,11  , 0,66  and 0,16  , respectively. 0 1 100 ZERO ORDER MOMENTS RATIO,  0 ,r 0.0 0.5 1.0 1.5 2.0 DAMAGE RATIO, E [ D ] / E ref [ D ] 8 0.1 5.0 10.0  c,r Figure 3 : Comparison between [ ] E D and [ ] ref E D : totally separated spectra. 0 1 100 ZERO ORDER MOMENTS RATIO,  0 ,r 0.0 0.5 1.0 1.5 2.0 DAMAGE RATIO, E [ D ] / E ref [ D ] 8 0.00 0.25 0.50 r 16 0.75 1.00 Figure 4 : Comparison between [ ] E D and [ ] ref E D : completely overlapped spectra.