Issue 78

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

Fatigue damage assessment for Sine-on-Random: a comparative analysis of the predictive capability and application limits of spectral methods

Filippo Veschi, Filippo Foiani, Massimiliano Palmieri, Giulia Morettini, Filippo Cianetti Department of Engineering, University of Perugia, Via G. Duranti 93, 06125, Perugia (Italy) filippo.veschi1@studenti.unipg.it, filippo.foiani@dottorandi.unipg.it, massimiliano.palmieri@unipg.it, giulia.morettini@unipg.it, filippo.cianetti@unipg.it

Citation: Veschi, F., Foiani, F., Palmieri, M., Morettini, G., Cianetti, F., Fatigue damage assessment for Sine-on-Random: a comparative analysis of the predictive capability and application limits of spectral methods, Fracture and Structural Integrity, 78 (2026) 44-73.

A BSTRACT . Mechanical and electronic components, mainly in aerospace and rotating machinery environments, are generally subjected to Sine-on-Random (SoR) excitations, where deterministic sinusoidal tones are superimposed on a broadband random vibration. While international testing standards require the validation of components under these complex profiles, the numerical evaluation of fatigue damage poses a major analytical challenge. The time domain rainflow counting method is computationally prohibitive. Conversely, frequency-domain spectral methods rely on Gaussian assumptions that are explicitly violated by SoR loads, leading to inaccurate damage estimates. To bridge this gap, researchers have developed two main strategies: practical approaches that synthesize an equivalent random Power Spectral Density (PSD) based on damage or energy equivalence, and rigorous theoretical methods deriving analytical cycle distributions. This paper evaluates and compares the available methodologies, aiming to highlight the benefits and limitations of each. Ultimately, this comparative study serves as a practical guide for engineers to select the most appropriate tool for fatigue damage assessment under SoR vibrations. K EYWORDS . Vibration fatigue, Sine on Random, Structural dynamics, Non Gaussian vibrations

Received: 15.06.2026 Accepted: 08.07.2026 Published: 15.07.2026 Issue: 10.2026

Copyright: © 2026 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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