Fatigue life estimation of structures under statistically and spectrally similar variable amplitude loading

• Published in: Mechanical systems and signal processing Vol. 161; p. 107856
• Main Authors: Li, He-Wen-Xuan, Chelidze, David
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2021
• Subjects: Cumulative damage rule; Fatigue life estimation; Load sequence effects; Nonlinear mechanical systems; Structural health monitoring; Surrogate data analysis; Variable amplitude loading; Cumulative damage rule; Variable amplitude loading; Structural health monitoring; Nonlinear mechanical systems; Fatigue life estimation; Load sequence effects; Surrogate data analysis
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2021.107856

•Enables the linear cumulative damage rule to consider load sequence effects.•Rainflow-counting based overload identification and residual stress variation modeling.•Accurate life prediction for statistically and spectrally similar variable amplitude loading.•Capability for damage prognosis to structures under in-service health monitoring.•No a priory knowledge to the applied load required. A new fatigue life prediction framework provides an improved life prediction under statistically and spectrally similar irregular variable-amplitude loading for a notched beam model. It enables the cumulative damage rule to account for the load sequence effects by modifying the probability density function of the stress-amplitude history through (1) identification of overloads based on the rainflow-counting algorithm; (2) analytical characterization of the overload retardation effects; and (3) correction to the damage rule using overload amplitude rate characterization. The fatigue lives estimated from experimentally acquired and synthetically generated load-time histories are compared to the ones generated from simulations that qualitatively reproduce the fatigue lives in physical experiments. The notable improvement in prediction accuracy outperforms the Palmgren–Miner’s rule and power-spectrum-based life estimation. The demonstrated application to the field acceleration data substantiates its use for in-service structural health monitoring and damage prognosis. This framework does not require a priory knowledge of the applied load, and it can be applied to other engineered structures with known structural and defect properties.