These slides were presented at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

Fibre-reinforced polymer laminates are nowadays increasingly used in many engineering industries due to their lightweight nature and the possibility to tailor laminate layups to achieve specific desired set of performance targets. Predicting the fatigue performance of structures made with such advanced materials is crucial to the design/analysis cycle, yet it remains challenging due to several reasons among which: (i) the complex microstructure and the high anisotropy of the composite materials, (ii) the variety of the damage mechanisms that occur under fatigue loadings, (iii) the non-linear relationships between the cyclic load amplitude and the fatigue life with a strong effect of the stress ratio and (iv) the complex and multiaxial nature of the loading during service conditions. This paper describes a predictive multiscale computational strategy for the assessment of the fatigue lifespan of composite structural parts made with any ply stacking sequence and subjected to fatigue loadings. The Integrated Computational Material Engineering (ICME) solution that will be presented addresses the above cited challenges. The methodology is built upon a combination of micromechanical and phenomenological models: On one hand, mean-field homogenization enables to accurately estimate the effective response of the composite at the ply level, taking into account the local fibres orientations (e.g. from draping simulation) and the constituents materials properties (elastic, viscoelastic and elastoplastic behavior). On the other hand, fatigue lifetime estimations are built on a cutting-edge, phenomenological multi-axial fatigue damage model that adapts to varying stress ratios. This advanced approach accounts for mean stress sensitivity and spatially varying stress ratio, ensuring precise and reliable predictions for durability under various loading conditions. This multiscale fatigue modelling approach allows to link the manufacturing process and the material'™s microstructure with the fatigue performance of the structural components enabling thus engineers to efficiently design optimized, yet safe parts that meet the desired durability.