Issue 78

F. Veschi et alii, Fracture and Structural Integrity, 78 (2026) 44-73; DOI: 10.3221/IGF-ESIS.78.04

0.05 k  ). The reference

Figure 14: Statistical comparison of the predictive models under SoR loading with a wide-band background ( RFC probability density function is depicted as a shaded grey histogram in the first panel.

1 k  ). The dashed grey line

Figure 15: Comparison of pseudo-damage estimates under SoR loading with a wide-band background (

RFC PD ). Percentages above the bars indicate the relative error of each

represents the reference rainflow counting pseudo-damage (

predictive method.

The comparative analysis results in the following considerations:  The evidence suggests that even in the presence of wide-band noise, when spectral coincidence occurs between the harmonic and stochastic components, Rice's approach emerges as the most accurate overall. It overestimates the pseudo-damage by merely 10%, showing excellent adherence to the reference PDF, cumulative load spectrum, and damage integrand curves.  The Equivalent PSD approaches yield conservative damage estimates, with errors of 13% for Irvine, 22% for RMS Eqv, 18.6% for Lalanne, and 8.6% for the WN Approximation. Despite the numerical proximity of the final Damage Index, none of these methods accurately reproduces the morphology of the true Load Spectrum. Instead, they predict an excessive number of high-amplitude cycles that are entirely absent from the original signal.

64